Static Procedure Research Articles

Influence of the P-delta Effect and Stiffness Irregularity on the Structural Behavior of Reinforced Concrete Buildings

In this research, the influence of the stiffness irregularity and the p-delta effect on the structural behavior of a reinforced concrete building is analyzed. The main objective is to determine the impact of the stiffness irregularity and the p-delta effect on the structural behavior in regular and irregular buildings. First, the linear dynamic analysis procedure is performed in order to determine the structural response in terms of drifts, shear force and moments per floor. Subsequently, we proceed with the nonlinear static analysis procedure to obtain the capacity curve of the structure. The post elastic stiffness and the overall ductility of the structure are determined from the capacity curve. Finally, a comparative analysis of the responses from the linear and nonlinear analysis is carried out to determine the percentage variation of the results. When analyzing the structures that consider the stiffness irregularity and the p-delta effect, variations of up to 16.50%, 11.00% and 14.00% have been obtained in drifts, shear force and moments per floor respectively, which are considerable values. When the p-delta effect is considered in structures with the presence of stiffness irregularity, there is a variation in stiffness of up to 59.85%. With this result it is explained that the p-delta effect produces a greater degradation of the overall stiffness of the structure.

Direct Displacement Based Design for Reinforced Concrete Framed Structures with Seismic Isolation

Direct displacement-based design is a nonlinear static procedure and has to check the suitability of the method against different types of ground motions namely far field, near field forward directivity and near field fling step. The method is applied for the buildings supported on a fixed base and hysteretic isolation bearings. Seismic isolators are provided between the foundation and the superstructure to minimize the influence of ground motion on the superstructure. The method is applied for four, eight and twelve storey reinforced concrete frame structures equipped with and without seismic isolators. Lead rubber bearing is used as seismic isolators. An equivalent damping ratio, derived from the particular characteristics of buildings supported on isolation bearings, is suggested. The energy dissipation mechanism in the isolators controls the displacement of the structure within acceptable limits at the level of the isolator. The results were validated with nonlinear time history analysis and were found to be in good agreement with the Direct displacement-based design methodology for far field ground motions. The performance of the building was measured for interstorey drift ratio, time period, acceleration of top floor, base shear, isolator displacement. This is an attempt to link the direct displacement-based design of the reinforced concrete building with seismic isolators subjected to the far field, near field forward directivity, near field fling step ground motions.

A Comprehensive Approach to Facial Reanimation: A Systematic Review.

Purpose: To create a systematic overview of the available reconstructive techniques, facial nerve grading scales, physical evaluation, the reversibility of paralysis, non-reconstructive procedures and medical therapy, physical therapy, the psychological aspect of facial paralysis, and the prevention of facial nerve injury in order to elucidate the gaps in the knowledge and discuss potential research aims in this area. A further aim was to propose an algorithm simplifying the selection of reconstructive strategies, given the variety of available reconstructive methods and the abundance of factors influencing the selection. Methodological approach: A total of 2439 papers were retrieved from the Medline/Pubmed and Cochrane databases and Google Scholar. Additional research added 21 articles. The primary selection had no limitations regarding the publication date. We considered only papers written in English. Single-case reports were excluded. Screening for duplicates and their removal resulted in a total of 1980 articles. Subsequently, we excluded 778 articles due to the language and study design. The titles or abstracts of 1068 articles were screened, and 134 papers not meeting any exclusion criterion were obtained. After a full-text evaluation, we excluded 15 papers due to the lack of information on preoperative facial nerve function and the follow-up period. This led to the inclusion of 119 articles. Conclusions: A thorough clinical examination supported by advanced imaging modalities and electromyographic examination provides sufficient information to determine the cause of facial palsy. Considering the abundance of facial nerve grading scales, there is an evident need for clear guidelines regarding which scale is recommended, as well as when the postoperative evaluation should be carried out. Static procedures allow the restoral of facial symmetry at rest, whereas dynamic reanimation aims to restore facial movement. The modern approach to facial paralysis involves neurotization procedures (nerve transfers and cross-facial nerve grafts), muscle transpositions, and microsurgical free muscle transfers. Rehabilitation provides patients with the possibility of effectively controlling their symptoms and improving their facial function, even in cases of longstanding paresis. Considering the mental health problems and significant social impediments, more attention should be devoted to the role of psychological interventions. Given that each technique has its advantages and pitfalls, the selection of the treatment approach should be individualized in the case of each patient.

Anti-polyphenol oxidase mechanism of oligomeric procyanidins and its application on browning control of “Baiyu” loquat during storage

The harvested loquat fruits are prone to browning, leading to a decline in fruit quality. Inhibiting activity of polyphenol oxidase (PPO) is an important way to prevent browning. In this study, we evaluated the inhibitory impact of oligomeric procyanidins (OPC) on hydroxylation of monophenol and oxidation of o-diphenol catalyzed by PPO and effect of OPC on loquat fruits storage. The obtained results revealed that OPC could attenuate the activity of monophenolase and diphenolase. For monophenolase activity, the inhibition rate was observed to be dose-dependent with an IC50 of 11.6 ± 3.4 μg/mL for the steady-state rate. For diphenolase activity, OPC inhibited PPO activity (IC50 = 15.75 ± 2.1 μg/mL) with a reversible and competitive mechanism and quenched fluorescence of PPO by forming OPC-PPO complex with one binding site in a static procedure. In addition, the data obtained from storage assays revealed that OPC could enhance the quality of harvested loquat fruits by attenuating the PPO activity, augmenting the content of total phenolics and flavonoids, and simultaneously delaying the browning of loquats. In this research, we identified a potent PPO inhibitor and expanded its potential as a food preservative.

Delamination onset in composite materials due to fatigue loading

An experimental program has been carried out for the evaluation of the delamination onset condition of various composite material systems, under the application of constant amplitude cyclic loading. Standard Double Cantilever Beam End Notch Flexure and Mixed Mode Bending specimens were used; the assessment of resistance to fatigue delamination onset has been performed by means of procedures defined in similitude with the standard static test procedures, introducing appropriate variants, where necessary. Three materials systems have been investigated: two carbon epoxy unidirectional materials and a carbon epoxy 5-harness satin. Normalised curves show a common trend and allow the identification of onset values for the evaluation of defects tolerance in the “no growth” approach. A similitude with the interlaminar fracture toughness measured in static tests, as a function of mode-mix ratio, has been highlighted with a higher influence of the mode I component. A modification of the Benzeggagh–Kenane relationship is proposed, that captures more faithfully the trend of the onset results.

A Historical Perspective on the Management of Facial Paralysis: From Ancient Civilizations to the Modern Era.

Documented evidence of facial nerve paralysis (FNP) and its treatment have been discovered in many early civilizations dating back centuries. Early records are present in art and scripts across ancient civilizations and have laid the groundwork for the implementation of many managements used in modern practice. Although the current management of FNP is still evolving, it includes a complex and multimodal spectrum of options ranging from pharmacologic therapy to facial physical therapy and neuromuscular training, and surgical facial reanimation interventions via static and dynamic procedures. The aim of this review is not to provide an up-to-date glossary of modern management options but rather to discuss the historical evidence of FNP and treatments leading up to current techniques and practices.

IMPA versus Cloud Analysis and IDA: Different Methods to Evaluate Structural Seismic Fragility

Well-known methods for seismic performance assessment, such as incremental dynamic analysis (IDA), multi-stripes analysis (MSA) and the cloud method, involve nonlinear response time-history analyses to characterize the relationship between the chosen damage measure versus intensity measure. Over the past two decades, many authors have proposed simplified procedures or nonlinear static approaches to develop fragility. In these procedures, the capacity of the system is evaluated by nonlinear static procedures (i.e., the capacity spectrum method (CSM), the N2 method, modal pushover analysis (MPA)) and the demand is derived by response spectra. In addition to the familiar ones, incremental modal pushover analysis (IMPA) is a novel nonlinear static procedure proposed in recent years, and it is used in this research to present an IM-based fragility estimation. The accuracy and effectiveness of different methods to assess vulnerability are investigated by comparing fragility curves derived by MPA-based cloud analysis, IMPA and cloud analysis against IDA. The comparison gives valuable insights on the influence of scaling on different sets of records; however, a more extended validation is needed to confirm the obtained results and draw more general conclusions. Results arise from two relatively small bins of record motions differing by ranges of Joyner-Boore distance and scattered in a range of magnitude are presented.

Eye Sphincter Reanimation in Facial Paralysis: Evaluation, Indications, Techniques, and Outcomes.

Facial nerve paralysis (FNP) sequela includes dysregulation of the ocular surface protective mechanism, nasolacrimal system pump failure and punctal eversion causing chronic epiphora, foreign body sensation, corneal injury, and, in the most severe cases, visual loss, particularly in the presence of comorbid corneal hypesthesia. Concerns over the ocular surface protection in FNP patients have led to the development of numerous static and dynamic procedures. While initial assessment of the FNP patients is complex and requires a comprehensive understanding of the blink reflex physiology, clinical evaluation and the use of additional work should be directed toward potential eye sphincter reanimation using a multidisciplinary approach. As with any treatment algorithm, numerous factors must be considered to provide an individualized treatment plan. In the case of FNP, it is important to consider denervation time, patient age, cause of paralysis, and neurologic severity of the paralysis. The aim of this article is to provide a thorough review of the physiology of the blink reflex, evaluation of the eye sphincter mechanism in FNP, and a comprehensive treatment algorithm incorporating static and dynamic procedures, along with a historical perspective.

On the Applicability of Conventional Seismic Design Methodologies to Hybrid RC‐Steel Systems

AbstractThis paper analyses the adequacy of the q‐factor approach when applied to hybrid RC‐steel systems. This approach is prescribed by EC8‐1 as the basic design method, and usually referred to as the most conservative. However, due to its simplicity and popularity for the design of new structures, practitioners are more likely to resort to it, than to the more complex nonlinear static and dynamic procedures, when dealing with the seismic assessment and strengthening of existing RC buildings. A case‐study application is thus presented to analyse and discuss the difficulties a practitioner will face when assessing the efficiency of a steel‐brace retrofitting system designed within the framework of EC8‐1.

Effect of Elastomeric Bearings in Bridge Piers

In this paper, the influence of elastomeric bearings is investigated in terms of seismic responses and presented under effects of severe ground motions. For this purpose, seismic performance of an isolated pier system is analytically studied by using time history analyses. The isolation system is assembled by elastomeric bearings composed of rubber layers and steel-shims. The bearings are located between pier-top ends and box-girder of the bridge deck. Seismic solutions are obtained for isolated system and non-isolated pier system known as rigid connection. Time-dependent response quantities are obtained in transverse direction for two strong quakes. Additionally, nonlinear static procedure is carried out to obtain lateral seismic capacity. Thus, the displacement and shear force capacity are determined for the considered pier systems. Seismic responses are comparatively presented in terms of superstructure and base response values. Thanks to the isolation system, the bearings have yielded lower peak displacements and base responses with seismic demand as well. On the other hand, higher seismic capacity has been obtained in case of isolation system and the results are presented by computed lateral capacity curves. The results show that the elastomeric bearing is an effective tool in lateral strength and modal behavior of the pier system as well.

Potential of remote sensing data to support the seismic safety assessment of reinforced concrete buildings affected by slow-moving landslides

Different forms of hazard can affect structures throughout their existence. The occurrence of a seismic event in areas exposed to different risks or already affected by other phenomena is highly likely, especially in countries characterized by high seismicity and equally high hydrogeological risk, as Italy. Nevertheless, the seismic safety assessment of reinforced concrete (RC) structures is commonly carried out considering the seismic action only, generally applied to an analytical model, neglecting the stress–strain state induced by previous ongoing phenomena. The aim of this work is to highlight the importance of the seismic safety assessment in a multi-hazard analysis, cumulating the action coming from two different hazards: landslide and earthquake. An existing RC building, located in an area affected by an intermittent landslide phenomenon with slow kinematics, that may also be subjected to strong earthquakes, is used as case study. The Differential Synthetic Aperture Radar Interferometry (DInSAR) approach is used to monitor the evolution in time of the landslide. DInSAR deformation data are used to detect surface ground movements applied to building foundations. A non-linear static analysis procedure is implemented for the code-based seismic safety assessment, in two different scenarios. The seismic assessment of the case-study building is implemented in a condition of structure deformed only for gravity loads, and, then, in a state of known landslide-induced deformed configuration. A comparison is proposed between the building seismic safety assessment performed in both cases, with or without the consideration of the landslide-induced displacements, showing the importance of a multi-hazard evaluation.

Fragility curves for different classes of existing RC buildings under ground differential settlements

Existing reinforced concrete (RC) buildings can be affected by different actions that can induce permanent or transient effects on them. While applications concerning the seismic vulnerability of existing RC buildings have been largely proposed in literature, the evaluation of the structural vulnerability because of hazards different from earthquake has been less dealt with. The focus of this work is to estimate the probability that the simulated RC buildings stock could reach a given Limit State for a certain intensity of imposed monotonically increasing ground differential settlements. A set of simulated FEM models, considering the geometrical and mechanical uncertainties in the representation of the existing RC frame buildings designed only for gravitational loads, has been created. The structural frames differ from each other for geometrical features and mechanical materials properties, obtained through a simulation process. The non-linear behavior of columns and beams is considered by applying a modeling approach specifically elaborated for RC members with plain bars. A FEM model for each simulated structural frame has been developed using the Open Application Programming Interface by using the programming and numeric computing platform MATLAB to run the modelling software SAP2000. Time by time, by scaling up the amplitude of the imposed base displacements, a non-linear static incremental procedure has been implemented. At each step of the analysis, a code-based seismic safety assessment has been carried out with reference to a specific ultimate Limit State considered in the Italian and European codes. The goal of the analysis has been to find the values of the significative structural response parameters (identified in this work as the maximum differential settlement and the deflection ratio) at the onset of the selected Limit State by using the critical demand to capacity ratio. Considering that these values are lognormally distributed, the structural fragility is then derived, showing how the vulnerability of the considered RC buildings stock is affected by the impact of the geometrical features and by the application direction of the differential settlements.

Static condensation of peridynamic heat conduction model

A model order reduction methodology for reducing the order of the peridynamic transient heat model is proposed. This methodology is based on the static condensation procedure. To set the development of the model reduction procedure on a sound mathematical setting, a nonlocal vector calculus was employed in the formulation of the heat transport problem. The model order reduction framework proposed in this study provides a technique to reduce the dimensionality of a peridynamic transport model while still maintaining accurate prediction of the model response. Moreover, the methodology can be adaptively applied to accommodate different resolution requirements for different sections of the model. Using numerical experiments, the proposed methodology is shown to be capable of accurately reproducing results of the full peridynamic transient heat transport problem.

Review of the energy-based design theory: Towards the application to self-centering systems

Self-centering systems exhibit superior performance during earthquake shaking with lower damage and less residual deformations. Although the equivalent static force design procedure is the commonly used one for most structural systems for seismic applications, the cumulative damage and the effective duration of earthquakes cannot be explicitly considered, which has significantly affected the behaviors and post-earthquake performance of self-centering systems. Energy-based design theory (EBDT), which introduces the energy demand as the critical parameter to establish relations with structural damage, has gained attention around the world in recent decades. The EBDT can provide comprehensive considerations for structural responses and damage in design procedures, especially for self-centering systems. However, few researches and actual energy design projects focus on the use of EBDT for self-centering systems. This paper intends to present thorough review of several critical issues in EBDT. Meanwhile, pivotal gaps that need to be further investigated towards the application of EBDT to self-centering systems are identified and discussed in the paper.

Static and Dynamic Assessment of Intelligence in ADHD Subtypes.

There is a debate about the measure of IQ in children with ADHD. Some studies report that, compared to static assessment procedures, dynamic assessment of intelligence can better measure cognitive modifiability and plasticity. The present study was designed to examine children belonging to different ADHD subtypes (inattentive, hyperactive/impulsive, and combined) in terms of both static (WISC scores) and dynamic measures (Modifiability index). Thirty-four children (12 ADHD-I, 10 ADHD-H, and 12 ADHD-C) were compared to a sample of 27 typically developing children. Results indicate that only the inattentive and the combined subtypes, compared with the normative sample, show lower IQ scores. The ADHD-I group presents generally low WISC scores and ADHD-H presents generally high WISC scores. Moreover, the ADHD-C group shows a low static score and a high dynamic score, indicating a wide breadth of Vygotskian children’s zone of proximal development. Static and dynamic measurements together can indeed be considered a comprehensive examination of intelligence levels in ADHD children and may be essential in predicting learning capacities.

Behavioural and Histological Abnormalities Observed in Heteroclarias Juveniles Exposed to Aqueous Extract of Ricinus communis Leaf Meal

The study evaluated the toxicity of aqueous extracts of Ricinus communis leaf on the juveniles of Heteroclarias, with mean weight 24.00 ± 0.25 g. Fish were exposed to varying concentrations of C (0.0, 2.0, 3.0, 4.0., 5.0 and 6.0 g/l), in a static bio-assay procedure for 96 hours. The 96 hours LC50 values were calculated at 4.37 g/l. Results indicated varying concentrations of R. communis resulted in different pathological alterations in the juveniles of Heteroclarias. Behavioural responses observed in experimental fish includes; erratic swimming, twitching, gaping, mucous discharge, skin discoloration and death. These responses and mortalities were significantly different (P˂0.05) in treatments with increasing concentration of R. communis when compared with the control. Experimental water showed increase in temperature (°C), pH and conductivity (µS/cm) with increase in test ingredient concentration while reverse was the case with dissolved oxygen (mg/l). Histolopathological assay of gills, liver and kidney, revealed different alterations in architecture, fragmentation and haemorrhage of gill filaments, fusion of the primary and secondary lamellae. Liver showed congestion of hepatic veins and foci hepatocellular degeneration while kidney revealed congestion of the renal artery, inflammation of the renal tubules, haematopoietic cells and nephrons, hyperplasia of the glomerular vessels, pyknotic nephrons and degenerated renal corpuscle.

Bovine Serum Albumin as a Potential Carrier for the Protection of Bioactive Quercetin and Inhibition of Cu(II) Toxicity.

Considering the protective ability of proteins and the potential toxicity of free Cu(II), it was proposed herein that the co-presence of protein could play an important role in suppressing the toxicity of free Cu(II) to the stability of bioactive quercetin if a flavonoid-protein-Cu(II) complex could be formed. In this study, the interaction between quercetin (a major flavonoid in the human diet) and bovine serum albumin (BSA) was investigated in the absence and presence of free Cu(II). The results demonstrated that both quercetin and free Cu(II) had a strong ability to quench the intrinsic fluorescence of BSA through a static procedure (i.e., formation of a BSA-monoligand complex). Site marker competitive experiments illustrated that the binding of both quercetin and Cu(II) to BSA mainly took place in subdomain IIA. The quenching process of free Cu(II) with BSA was easily affected by quercetin, and the increased binding capacity possibly resulted from the generation of a ternary quercetin-BSA-Cu(II) complex. The stability and free radical scavenging activity of bioactive quercetin during incubation was promoted in the BSA-diligand complex relative to a quercetin-Cu(II) complex. A quercetin-Cu(II) system could generate reactive oxygen species such as hydrogen peroxide (H2O2) and hydroxyl radicals (•OH), which were significantly inhibited upon BSA binding. Consistently, the cytotoxicity of the quercetin-Cu(II) system to endothelial cells was decreased in the BSA-diligand complex, where the co-presence of BSA played an important role. These results suggest the possibility and advantage of developing albumin-based carriers for the protection of bioactive components and suppression of Cu(II) toxicity in their biomedical and nutritional applications.

Cannabis sativa Extract Induces Apoptosis in Human Pancreatic 3D Cancer Models: Importance of Major Antioxidant Molecules Present Therein.

In recent years, interest in Cannabis sativa L. has been rising, as legislation is moving in the right direction. This plant has been known and used for thousands of years for its many active ingredients that lead to various therapeutic effects (pain management, anti-inflammatory, antioxidant, etc.). In this report, our objective was to optimize a method for the extraction of cannabinoids from a clone of Cannabis sativa L. #138 resulting from an agronomic test (LaFleur, Angers, FR). Thus, we wished to identify compounds with anticancer activity on human pancreatic tumor cell lines. Three static maceration procedures, with different extraction parameters, were compared based on their median inhibitory concentration (IC50) values and cannabinoid extraction yield. As CBD emerged as the molecule responsible for inducing apoptosis in the human pancreatic cancer cell line, a CBD-rich cannabis strain remains attractive for therapeutic applications. Additionally, while gemcitabine, a gold standard drug in the treatment of pancreatic cancer, only triggers cell cycle arrest in G0/G1, CBD also activates the cell signaling cascade to lead to programmed cell death. Our results emphasize the potential of natural products issued from medicinal hemp for pancreatic cancer therapy, as they lead to an accumulation of intracellular superoxide ions, affect the mitochondrial membrane potential, induce G1 cell cycle arrest, and ultimately drive the pancreatic cancer cell to lethal apoptosis.

Pushover analysis of reinforced concrete building seismically designed based on SNI 1726-2019

Indonesia has experienced many earthquakes due to its geographic location. Therefore, the Indonesian National Standard (SNI) for seismic design has recently been released for immediate application. In this study, nonlinear static analysis procedure is adopted to evaluate the seismic performance of reinforced concrete frame structures seismically designed using SNI. The main purpose of this study is to assess the safety level of the building under an earthquake. Three typical building with different height have been evaluated. The analysis is conducted using the commercial finite element ETABS. The performance level is determined according to ASCE41-17 acceptance criteria. The results revealed that the SNI designed building generally comply with to the acceptance criteria.

Displacement-based seismic performance assessment of multi-span steel truss bridges

Simplified mechanics-based approaches for the seismic performance analysis are used for the risk assessment of large bridge portfolios. This study evaluates the applicability and effectiveness of displacement-based assessment (DBA) and nonlinear static procedures for multi-span railway steel truss bridges. Although built in the first part of the last century, these historical bridges are currently in service within the European railway networks, and their seismic performance is poorly investigated in the literature. Direct DBA algorithms and pushover-based procedures aimed at seismic performance assessment and fragility analysis of bridges are presented and tested within a set of case studies parametrically generated by using an archetype steel truss bridge. The first part of this study focuses on the seismic analysis of steel braced towers which, in many situations, compose the substructure of steel truss multi-span bridges. A simplified pseudo-pushover and an accurate equivalent viscous damping formulation are proposed to be used for the approximate performance displacement assessment of these structural components. The second part discusses the accuracy of the investigated approaches for multi-span steel truss bridges through comparisons with nonlinear time history analysis. The results of the parametric analysis are used to propose recommendations for an appropriate DBA or pushover-based strategy for the deterministic performance assessment and fragility analysis with reference to the damage state of the supporting towers or bridge serviceability in terms of superstructure transverse deformation.