Irregular Configuration Research Articles

Equivalent frame discretisation for URM fa\xe7ades with irregular opening layouts

Researchers and practitioners widely employ simplified Equivalent Frame Models (EFM) for reproducing the in-plane governed response of unreinforced brick masonry (URM) structures, as they typically represent an acceptable compromise between numerical accuracy and computational cost. However, when considering URM structural systems with irregular opening distribution, the definition of the effective height and length of deformable components (i.e. pier and spandrel elements) still represents an open challenge. In this work, the influence of irregular distribution of openings on the predicted lateral response of full-scale URM façades was investigated. To this end, several geometrical combinations characterised by various degrees of irregularity were considered and idealised according to commonly employed EF discretisation approaches. Then, after a preliminary calibration process against experimental tests on both individual piers and a full-scale building façade, EFM results were compared with micro-modelling predictions, carried out within the framework of the Applied Element Method and used as a benchmark. Although in specific irregular configurations using some discretisation approaches, macro and micro-models converge to similar results, non-negligible differences in terms of initial lateral stiffness, base-shear and damage distribution were observed with other EF schemes or opening layouts, thus indicating that a careful selection of appropriate criteria is indeed needed when performing in-plane analyses of URM systems with irregular opening distributions. Finally, building on inferred simulated data, potential solutions are given to overcome typical EF discretisation issues and better approximate micro-modelling outcomes.

Negative tension controls stability and structure of intermediate filament networks

Networks, whose junctions are free to move along the edges, such as two-dimensional soap froths and membrane tubular networks of endoplasmic reticulum are intrinsically unstable. This instability is a result of a positive tension applied to the network elements. A paradigm of networks exhibiting stable polygonal configurations in spite of the junction mobility, are networks formed by bundles of Keratin Intermediate Filaments (KIFs) in live cells. A unique feature of KIF networks is a, hypothetically, negative tension generated in the network bundles due to an exchange of material between the network and an effective reservoir of unbundled filaments. Here we analyze the structure and stability of two-dimensional networks with mobile three-way junctions subject to negative tension. First, we analytically examine a simplified case of hexagonal networks with symmetric junctions and demonstrate that, indeed, a negative tension is mandatory for the network stability. Another factor contributing to the network stability is the junction elastic resistance to deviations from the symmetric state. We derive an equation for the optimal density of such networks resulting from an interplay between the tension and the junction energy. We describe a configurational degeneration of the optimal energy state of the network. Further, we analyze by numerical simulations the energy of randomly generated networks with, generally, asymmetric junctions, and demonstrate that the global minimum of the network energy corresponds to the irregular configurations.

Configuration Optimization of Optical Tomography Based on Fan-Beam Lasers

Sensor configuration of optical tomography refers to the arrangement of laser emitters and light receivers, which is a key factor for the reconstruction performance. This work proposes an optimization method for the tomography configuration based on fan-beam lasers. Firstly, the angular arrangement of the emitters and receivers is organized into a vector. Then, the uniformity coefficient of the sensitivity map is selected as the predictor of the reconstruction performance. Its effectiveness has been investigated and verified in this work. Finally, Genetic algorithm (GA) is used to search for the optimal solution of the vector. The fitness function of GA is the uniformity coefficient. The number of the emitters and receivers is both predetermined as 25 according to our previous work. The optimized solution provided by GA is an irregular configuration with uniformity coefficient of 0.295. Reconstruction for randomly generated distributions and some specific distributions has been conducted. The reconstruction results verify the superiority of the optimized configuration over other random and regular configurations. The optimized configuration can reconstruct practical distribution effectively with mean error of 16.9%, and the ’ soft-edge ’ and ’hard-edge’ phantoms can be clearly reconstructed. Meanwhile, a practical tomography system is developed based on the optimized configuration and its effectiveness has also been verified according to static experiments.

Dynamic Behaviour Comparison of an Irregular Edifice with Different Locations of Floating Column and Shear Wall

Abstract: Architects nowadays develop attractive edifices, and floating columns are widely employed in this process. Floating columns are used not only to provide a magnificent perspective but also when a vast open area is necessary. Edifices with irregular configurations are more vulnerable to earthquakes and hence, suitable shear wall placement is required to ensure the edifice's stability. Many multi-storey edifices collapsed in seconds after the Bhuj Earthquake (Jan 26, 2001), due to the presence of soft stories, floating columns, and mass anomalies. As a result, knowing the seismic reactions of these buildings are vital for constructing earthquake-resistant assemblies. The relevance of a Floating Column and the existence of a shear wall in an irregular multistorey building is highlighted in this study. Dynamic seismic behaviour of a G+18 irregular edifice with different locations of the floating column and different positions of the shear wall is explored in this research. The edifice is analysed and compared with the model without shear walls and floating columns to examine the alterations. The dynamic analysis is carried out using Response Spectrum Analysis and storey drift, storey displacement and base shear are calculated and finally, software compression is computed for different zones. The analysis is carried out by Indian standardized codes IS 1893:2016 and IS 456:2000 which are the codes specified by the Bureau of Indian Standards for earthquake resistance edifice design and plain and reinforcement concrete design respectively. Keywords: Floating Column, Shear Wall, Irregular Edifice, Seismic behaviour, Response Spectrum Analysis, storey drift, storey displacement, base shear.

Comparative analysis of behaviour of horizontal and vertical irregular buildings with and without using shear walls by ETABS software

At present days building a structure with all the regular configurations is not feasible in most of the cases due to the irregular plot dimensions, aesthetic visual and functional requirements in the urban cities. The structure with more irregular configuration either horizontally or vertically are more vulnerable to earthquake & wind forces which leads to collapses of structure, property loss and casualties. Although a considerable amount of research effort was made on capturing the responses of irregular configuration structures under the earthquake forces, but well-accepted guidelines for multi storey irregular configuration structures are still yet to be framed. In this aspect a question might arise in the mind of structural engineers designing a high-rise structure i.e., which irregular configuration of structures and type of structures provide considerably good responses to the earthquake forces in reducing the damage caused by earthquakes and cost effective in implementing. A well-known answer is that shear walls provide good response to resist lateral forces when added to a structure.In the present study a structure with horizontal irregularity, vertical irregularity, Stiffness irregularity and Mass irregularity buildings with and without shear wall is considered and responses of the buildings are compared. Modeling of these 4 types of models with and without shear walls are done with ETABS software for G + 15 storey. The goal of the study is to compare model results like Stiffness, Displacement, Shear & Drift values and find out which model performs better. Vertical geometrical irregular building with shear wall has shown considerably better performance than other irregular buildings.

Socio-Spatial Relation in Small Island (Case Study: Karanrang Island, South Sulawesi, Indonesia)

Social interaction is an influential factor in shaping a community in a small island. There is a lack of study on how multi-ethnic groups of people living in a small island have shaped their community and maintained social harmony. This study identifies and analyzes the social interaction of residents in Karanrang Island in South Sulawesi, Indonesia. It focuses on how the social behavior of the residents has formed the spatial pattern of residential and community areas, including open spaces. Data of the residents' social behavior, activities, spatial layout of buildings, pathways, and major amenities were gathered from spatial mapping and on-site surveys. The analysis of socio-spatial patterns used the space syntax analysis method, namely Axial Analysis and Visibility Graph Analysis (VGA). The result shows that socio-spatial integration tends to occur in the irregular spatial configuration of residential areas, whereas socio-spatial segregation tends to occur in the regular spatial configuration. Furthermore, from the viewpoint of socio-spatial relation, the factors of activity location, residential density, and distance between houses significantly relate to social aspects such as community participation in social activities and willingness to assist neighbors. These findings are expected to provide consideration for the development of the socio-spatial structure that is suitable with the characteristics of small island communities, also to contribute to the sustainability of social order in the residential neighborhood of small islands.

Seismic behaviour of irregular steel frames with beam and joint energy dissipation

This paper investigates the seismic performance of steel moment resisting frames, exploring the potential for energy dissipation not only in the beams but in the beam-to-column joints too. Such an approach practically doubles the possible locations for dissipative zones in the structure but on the other hand places requirements for ductile behaviour on the connections. A design methodology that facilitates the formation of plastic hinges in the beam-to-column joints and the beams at the same time, is presented and examined in comparison to typically designed frames with rigid joints. A number of 24, 2D regular and irregular frame configurations are studied numerically, employing both nonlinear static and dynamic analyses. The examined configurations involve either irregular mass distribution across the floors or stiffness discontinuities of the framing across the floors and the bays. The results indicate a great reduction in ductility demands for the frames with energy dissipation in the beams and the joints concurrently, while other metrics of their seismic response, such as interstorey drifts and lateral capacity remain practically unaffected.

The value of having an initial word recognition score for a precise prognosis of idiopathic sudden sensorineural hearing loss

ObjectiveAlthough the hearing thresholds of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) closely relate to the prognosis that results in progressive floor effects, many studies have usually used hearing thresholds as the main outcome of the measurement of prognostic factors. The present study aimed to identify the prognostic factors related to initial hearing tests and speculates the effects of word recognition score (WRS) on the prognoses for patients with ISSNHL. MethodsBetween March 2011 and November 2020, we retrospectively reviewed chart profiles of 2,636 ISSNHL patients. The 180 patients who met the inclusion criteria were asked to participate in the present study. Based on their initial WRS, all these patients were divided into good WRS (GW) and poor WRS (PW) groups with 52% as the cut-off points. Demographic, clinical, and audiological variables, such as age, onset time, duration of treatment, gender, ear side, comorbidities (i.e., hypertension, diabetes mellitus, tinnitus, dizziness), hearing configuration (i.e., ascending, descending, flat, irregular, and profound), treatment options (i.e., systemic corticosteroid therapy per oral, intratympanic steroid injection, and hyperbaric oxygen therapy), and WRS were analyzed as being underlying prognostic factors. ResultsBoth groups showed significantly different distributions for hearing thresholds and hyperbaric oxygen therapy (HBOT) as general characteristics. The results of a multivariate logistic regression analysis showed that the odds ratio (OR) of age (OR: 0.96, 95% CI: 0.59 – 24.25), duration of treatment (OR: 0.98, 95% CI: 0.96 – 1.00), ascending configuration (OR: 4.97, 95% CI: 1.64 – 16.62), irregular configuration (OR: 4.58, 95% CI: 1.62 – 13.79), and WRS (OR: 1.01, 95% CI: 1.00 – 1.02) were the significant prognostic factors for all the patients. Further analysis of those patients with WRS under 52% cut-off points showed that an ascending configuration (OR: 5.87, 95% CI: 1.18 – 35.99), irregular configuration (OR: 8.03, 95% CI: 1.69 – 46.30), and WRS (OR: 1.05, 95% CI: 1.01 – 1.10) significantly affected the prognosis. As the initial WRS of ISSNHL patients decreased, the OR of the WRS itself increased. These results suggested that the importance of WRS as the prognostic factor was stressed for PW patients. ConclusionThe age, duration of treatment, initial hearing configuration (ascending and irregular types), and WRS were the significant prognostic factors for patients with ISSNHL. It was learned that WRS could be a remarkable prognostic factor to consider, especially for ISSNHL patients with poor WRS.

Direct numerical simulation of deformable rising bubbles at low Reynolds numbers

We investigate numerically the dynamics of freely rising gas bubbles driven by buoyancy at low Reynolds numbers, focusing on two distinct characteristics: the clustering morphology and the probability density functions (p.d.f.) of the velocity fluctuations for bubbles. A modified Volume-of-fluid (VOF) method is implemented in our direct numerical simulations to circumvent the nonphysical coalescence between bubbles. Four values of the gas fraction are studied: 5%, 10%, 15%, and 20%. The Eötvös number and the Galileo number are fixed at Eo = 2 and Ga = 855, respectively. For a single rising bubble, the Reynolds number according to the terminal velocity and the bubble diameter is around 27, displaying an ellipsoidal shape. For a swarm of bubbles, both irregular and regular clustering configurations are observed in our numerical simulations as we vary the gas fraction, which can only be realized at high Reynolds numbers in the previous experiments due to the low gas fraction limit. Moreover, we find that the p.d.f.s for bubble velocity fluctuations exhibit distinctly different behavior from the high Reynolds number experiments. The horizontal components for these p.d.f.s approach Gaussian distributions only when the gas fraction is high, i.e., α=15% and 20%. It suggests that the strong bubble–bubble interaction through their flow wakes is an efficient way to trigger the flow into turbulent states.

Curlometer Technique and Applications

AbstractWe review the range of applications and use of the curlometer, initially developed to analyze Cluster multi‐spacecraft magnetic field data; but more recently adapted to other arrays of spacecraft flying in formation, such as MMS small‐scale, 4‐spacecraft configurations; THEMIS close constellations of 3–5 spacecraft, and Swarm 2–3 spacecraft configurations. Although magnetic gradients require knowledge of spacecraft separations and the magnetic field, the structure of the electric current density (for example, its relative spatial scale), and any temporal evolution, limits measurement accuracy. Nevertheless, in many magnetospheric regions the curlometer is reliable (within certain limits), particularly under conditions of time stationarity, or with supporting information on morphology (for example, when the geometry of the large scale structure is expected). A number of large‐scale regions have been covered, such as: the cross‐tail current sheet, ring current, the current layer at the magnetopause and field‐aligned currents. Transient and smaller scale current structures (e.g., reconnected flux tube or dipolarisation fronts) and energy transfer processes. The method is able to provide estimates of single components of the vector current density, even if there are only two or three satellites flying in formation, within the current region, as can be the case when there is a highly irregular spacecraft configuration. The computation of magnetic field gradients and topology in general includes magnetic rotation analysis and various least squares approaches, as well as the curlometer, and indeed the added inclusion of plasma measurements and the extension to larger arrays of spacecraft have recently been considered.

Behavior of vertically irregular structures near mines: Comparison of responses under seismic and mine blast‐induced ground motion

SummaryDue to architectural and functional considerations, buildings with irregular configurations are frequently constructed with rapid urbanization. During a seismic or blast activity, the performance of a building depends on various factors like adequate lateral strength, stiffness, ductility, regularity, and the extent of simplicity in the configuration. The irregular distributions of the stiffness, mass, and strength in the plan and height of the building create irregularity within the structures. The purpose of this study is to understand the nature of response under seismic ground motion and that obtained from ground vibration generated due to mine blasts if such buildings are situated near mines. This study also emphasizes on identifying the critical location of stress concentration of the structures under both seismic and mine blast‐induced ground motion. Base shear, fundamental natural periods, mode shapes, and member forces for a few buildings with typical irregular configurations and similar buildings with regular counterparts are obtained. Nonlinear dynamic analysis has been carried out on irregular buildings for confirming the trends in behavior observed from linear dynamic analysis. Since the mine blasts take place sequentially, the study also aims to prescribe a suitable delay interval between such series blasts to minimize the vulnerability of vertically irregular seismic structures to the possible extent.

A local meshless analysis of dynamics problems / Uma análise local desordenada dos problemas dinâmicos

This paper is concerned with new formulations of local meshfree numerical method, for the solution of dynamic problems in linear elasticity, Integrated Local Mesh Free (ILMF) method. The key attribute of local numerical methods is the use of a modeling paradigm based on a node-by-node calculation, to generate the rows of the global system of equations of the body discretization. In the local domain, assigned to each node of a discretization, the work theorem is kinematically formulated, leading thus to an equation of mechanical equilibrium of the local node, that is used by local meshfree method as the starting point of the formulation. The main feature of this paper is the use of a linearly integrated local form of the work theorem. The linear reduced integration plays a key role in the behavior of local numerical methods, since it implies a reduction of the nodal stiffness which, in turn, leads to an increase of the solution accuracy. As a consequence, the derived meshfree and finite element numerical methods become fast and accurate, which is a feature of paramount importance, as far as computational efficiency of numerical methods is concerned. The cantilever beam was analyzed with this technique, in order to assess the accuracy and efficiency of the new local numerical method for dynamic problems with regular and irregular nodal configuration. The results obtained in this work are in perfect agreement with Mesh-Free Local Petrov-Galerkin (MLPG) and the Finite Element Method (FEM) solutions.

S2972 Primary Squamous Cell Carcinoma of the Ileum - A Rare Entity

Introduction: The small intestine is the most common site for metastatic spread in the gastrointestinal tract. Squamous cell carcinoma (SCC) from a wide variety of sites can metastasize to the small intestine. Primary SCC of the small intestine are rare. We present a rare case of primary SCC of the ileum. Case Description/Methods: A 70-year-old male presented with complaints of abdominal pain for 5 days. Physical exam revealed tenderness on palpation on the right lower quadrant. Labs significant for WBC count of 13k/ul and lactic acid of 10.9 mmol/l. CT Abdomen revealed small bowel obstruction and suspected perforated mass within the ileum. (figure A). Mesenteric lymphadenopathy concerning for metastasis. Laparoscopy revealed an ileal perforation with a matted mass of the distal small intestine which was resected and ileocolonic anastomosis was performed. Gross exam revealed a 6.8*4.7cm ill-defined mass, irregular in appearance with tan pink and nodular texture with areas of necrosis. The mass was submucosal in location, extending to the adjacent mesenteric soft tissue. Histology revealed an invasive poorly differentiated SCC with perforation and invasion of the mesenteric lympho-vascular spaces (figure B). Neoplastic cells were positive for p40(figure C), p63(figure D), ck5/6 and pancytokeratin while negative for ck7, ck20, cdx2, ttf1, synaptophysin, chromogranin, cd45 and S100. The patient had a prolonged postoperative course with multi organ failure, was made palliative on postoperative day 14 and he expired on the same day. Discussion: Several mechanisms have been proposed for primary SCC of the small bowel. Some of which include submucosal squamous epithelium undergoing malignant transformation, aberrant transformation of stem cells into squamous cells with subsequent malignant change. It is difficult to differentiate between primary versus metastatic squamous cell carcinoma of the small bowel. In our patient, imaging studies, immune-histochemical staining and histology results points towards a primary SCC of the ileum. We believe that our patient had primary SCC of the terminal ileum without underlying adenoma, inflammatory disease, or duplication. Optimal treatment and the prognosis are unknown because of the rarity of this condition. Surgery is the mainstay in the management of the disease. Due to the small number of cases available in the literature, the effects of chemotherapy and radiotherapy on the survival and recurrence are unknown.Figure 1.: A CT abdomen axial view showing irregular configuration of a loop of small bowel with adjacent air bubbles suspicious for a perforated mass located within the ileum. B Histology demonstrating tumor nests, composed of large cells with hyperchromatic, pleomorphic nuclei and eosinophilic cytoplasm infiltrating the muscularis propria. Neoplasm is diffusely positive for P40 (C) and p63 (D)-indicating squamous cells

Rapid decision-making tool of piloti-type RC building structure for seismic performance evaluation and retrofit strategy using multi-dimensional structural parameter surfaces

Piloti-type reinforced concrete building structures have vertically irregular configurations composing a moment frame for parking spaces in the lower story and heavy-weight shear wall system for residential spaces in the upper stories. Due to these vertically irregular configurations, such building structures are governed by a soft-story mechanism, damage concentration on the first story. Since the 2017 Pohang earthquake led to severe damage to the piloti-type building structures on a regional level, a decision-making tool mitigating the seismic damage for future events is needed. This paper aimed to propose a rapid decision-making tool promptly estimating seismic damage with simple information and determining a retrofit scheme using a pre-developed extensive database, i.e., multi-dimensional structural parameter surfaces. The multi-dimensional surfaces were created using a simplified modeling approach with five structural parameters: period, strength ratio, and ductility controlling failure modes as the input, and peak inter-story drift ratio and demand-to-capacity ratio as the output. The proposed methodology was validated using a finite element model for the piloti-type building structure with a soft-story mechanism. The seismic responses detected from the multi-dimensional surfaces have a slight difference from those of the numerical model. Nevertheless, the rapid tool predicted a reasonable agreement with performance evaluation from the finite element simulation. In addition, the rapid tool provided feasible retrofit options to meet target performance using brief structural information. Due to its simplified process, the proposed tool can be implemented to the regional seismic assessment for the residential areas where the piloti-type building structures were highly concentrated.

Comparison of Analysis and Design of Regular and Irregular Configuration of Multi Story Building in Seismic Zones

Abstract: This paper is concerned with the effects of various vertical irregularities on the seismic response of a structure. The objective of the project is to carry out Response spectrum analysis (RSA) and Time history Analysis (THA) of vertically irregular RC building frames and to carry out the ductility based design using IS 13920 corresponding to Equivalent static analysis and Time history analysis. Comparison of the results of analysis and design of irregular structures with regular structure was done. The scope of the project also includes the evaluation of response of structures subjected to high, low and intermediate frequency content earthquakes using Time history analysis. Three types of irregularities namely mass irregularity, stiffness irregularity and vertical geometry irregularity were considered. According to our observation, the storey shear force was found to be maximum for the first storey and it decreases to minimum in the top storey in all cases. The mass irregular structures were observed to experience larger base shear than similar regular structures. The stiffness irregular structure experienced lesser base shear and has larger inter-storey drifts. The absolute displacements obtained from time history analysis of geometry irregular structure at respective nodes were found to be greater than that in case of regular structure for upper stories but gradually as we moved to lower stories displacements in both structures tended to converge. . Lower stiffness results in higher displacements of upper stories. In case of a mass irregular structure, time history analysis gives slightly higher displacement for upper stories than that in regular structures whereas as we move down lower stories show higher displacements as compared to that in regular structures. When time history analysis was done for regular as well as stiffness irregular structure, it was found that displacements of upper stories did not vary much from each other but as we moved down to lower stories the absolute displacement in case of soft storey were higher compared to respective stories in regular structure. Tall structures were found to have low natural frequency hence their response was found to be maximum in a low frequency earthquake. It is because low natural frequency of tall structures subjected to low frequency earthquake leads to resonance resulting in larger displacements. If a high rise structure (low natural frequency)is subjected to high frequency ground motion then it results in small displacements. Similarly, if a low rise structure (high natural frequency) is subjected to high frequency ground motion it results in larger displacements whereas small displacements occur when the high rise structure is subjected to low frequency ground motion.

Correlation of choriocapillaris hemodynamic data from dynamic indocyanine green and optical coherence tomography angiography

To investigate the correlation between posterior pole choroidal blood flow evaluated with digital subtraction indocyanine green angiography and enface optical coherence tomography angiography (OCTA). Imaging in animal study. The anatomy of 2 cynomogulus monkeys was studied. Each monkey was given a 0.75 mg/kg injection of indocyanine green in the saphenous vein. The dynamic angiographic filling sequence was recorded at 15 frames per second using the Heidelberg Spectralis. After image registration, sequential frame subtraction was used to image the dye front moving through the choroid. The OCTA was obtained by frame averaging nine separate choriocapillaris slab flow images obtained from the Zeiss Plex Elite 9000. Posterior pole choriocapillaris filling pattern in relation to the choriocapillaris anatomy as imaged by OCTA. In the posterior pole, the choriocapillaris fills in the pattern of discrete units with variable sizes and shapes. The cycle of dye filling begins in the peripapillary area and progresses toward the periphery in a wavelike manner. This filling pattern repeats in a cyclical manner, consistent with the cardiac cycle. OCTA shows a uniform mesh of vessels. While OCTA shows a uniform meshwork appearance of the choriocapillaris, the dynamic dye angiography suggests an irregular configuration of functional units partitioned by pressure gradients as opposed to structural boundaries. Disturbance of local perfusion pressure within choroidal vasculature may result in abnormal flow patterns, which could be evaluated in the clinic using commercially available equipment.

On the Effectiveness of Rotation-Based Arrangement Optimization in the Pattern Synthesis of Subarrayed Phased Array

This letter presents a rotation-based optimization method for pattern synthesis of subarrayed phased arrays. In order to keep a good beam scanning ability at different steering angles, the optimization problem is reasonably defined where the objective is taken as minimizing the maximum sidelobe level at a series of steering angles, and both the arrangement variables and the scanning variables are optimized simultaneously. The mutual coupling of the iteratively rotated arrays is rigorously considered in the synthesis. In order to solve the synthesis problem effectively, the design sensitivities are derived analytically and the synthesis is actualized by using a gradient-based algorithm. Typical examples, with considering different regular subarray configurations and the state-of-art irregular subarray configurations, are provided to validate the effectiveness of the proposed approach.

Fragility analysis of steel MRFs: Effects of frequency-content components of near-fault pulse-like ground motions and setbacks

Near-fault (NF) pulse-like ground motions may contain long-period velocity pulses and high-frequency acceleration records, which impose significant damage on structures. This paper attempts to investigate the effects of forward directivity pulses and the high-frequency (residual) components of such records on the seismic performance of regular and setback structures. To this end, a group of ten-story steel moment-resisting frames with regular and irregular configuration were subjected to 55 NF records and their corresponding components. The records were classified into four groups to evaluate the effects of the ratio of the pulse period to the fundamental period of the structure, TP/T1, which is known to have critical effects on structural responses. Incremental dynamic analyses were carried out to develop fragility curves. The results revealed that pulse records with TP/T1 ≠ 1 can be the representatives of original NF pulse-like records to develop fragility curves for the regular structures. However, the fragility curves for setback frames should be developed under the original NF earthquake records, when TP/T1 ≤ 1. The residual part is the predominant component for the regular structure only when TP/T1 ≈ 1. However, in some setback frames, the effects of the residual part in exceeding the performance level are considerable even when TP/T1 > 1. Meanwhile, pulse records with TP/T1 ≈ 0.5 are the most damaging directivity pulses in the IO limit state of regular and setback structures, while the pulse records with TP/T1 ≈ 2 and TP/T1 ≥ 2 are the most critical pulses in the LS and CP performance levels of regular and setback frames, respectively.

Magnetic Resonance Arthrographic Findings After Hip Labrum Resection Versus Refixation

The aim of this study was to evaluate whether new tissue formation occurs after labral debridement/excision, and, if so, which morphological features are typical for a neo-labrum. The authors further compared the findings after labrum resection with those seen after labrum refixation. Patients with femoroacetabular impingement who underwent hip arthroscopy or surgical hip dislocation to address a labrum pathology were retrospectively included, and postoperative magnetic resonance arthrography studies were assessed. Forty-two patients had undergone either labrum resection (n=25) or refixation (n=17), performed arthroscopically (47.6%) or via surgical hip dislocation (52.4%). In the subgroup of patients after debridement/resection, there was anterosuperior/superior scar tissue in 83.5%, with amorphous configuration in 92%, irregular surface in approximately two-thirds of the cases, and a mean±SD thickness of 7.0±2.7 mm. A labrum-like shape of the scar plate was seen in 7.7%. Regarding the subgroup of patients who had undergone labral refixation, an irregular or rounded labrum shape was noted in 26.5% and 51.3% of cases, respectively, with a triangular shape in less than one-fourth of cases. Labrum re-tears (35.7%) were mainly observed at the base (71.7%), rather than within the labral substance (28.4%). New tissue formation can be observed in the majority of cases after excision of the hip labrum, with amorphous and irregular surface configuration compared with a native labrum. This new tissue should therefore be referred to as scar tissue rather than as neo-labrum. Whether scar tissue is inferior to a refixed labrum needs to be further elucidated in follow-up studies. [Orthopedics. 2021;44(4):e607-e613.].

Seismic Analysis of RCC Structure with Change in Vertical Irregularities Floor Wise

Multi-storey RC Structure has subjected to most dangerous earthquakes. It was found that a main reason for the failure of RC building is irregular distributions of the mass, stiffness and strength or due to irregular geometrical configurations. In a reality, many existing buildings contain an irregularity due to functional and aesthetic requirements. However, past earthquake records show the poor seismic performance of this structure. This is due to an ignorance of the irregularity aspect in formulating the seismic design methodologies by the seismic codes The review of seismic design codes and reported research studies show that the irregularity has been quantified in terms of magnitude ignoring the effect of a location of an irregularity. In the present work vertical Irregularities were analysed at various floor levels and comparative results were plotted from this it is found that a more amount of research can be done on this topic.