Cyclic Protocol Research Articles

A proposal for the optimization of the geometric configuration of a hollow cylindrical steel damper with slots

The energy dissipation capacity (EDC) of most current configurations of yielding steel dampers is susceptible to be improved by applying optimization concepts. Thus, this study proposes a methodology to enhance the EDC of a slotted hollow cylinder steel (HCS) damper under a cyclic displacement protocol while keeping the same quantity of material via shape optimization. The simulated annealing algorithm was selected for solving the optimization problem as it uses only one candidate solution per iteration, reducing the computational cost associated with the EDC computation. In addition, the finite element software ABAQUS is used to model the behavior of the steel damper under cyclic loads. A code is elaborated using the Python programming language for the optimization process, containing the instructions to be executed in ABAQUS. Five slot configurations were proposed for the initial damper to determine the effect of the initial solution on the optimized HCS damper. The results show that the proposed optimization process obtains optimized models with stable hysteretic behavior and a significantly higher energy dissipation capacity than the initial models. The optimal configuration presented an EDC of 5543 J, 16% higher than the HCS damper without slots and with the same material quantity. The material is mainly located parallel to the beam, simulating two 2D shear steel plates. The difference in EDC with other optimized configurations reaches 955 J, indicating the dependence of the solution on the initial damper configuration. In addition, the difference in the optimized damper topologies proves the multi-modality characteristic of the problem. The proposed algorithm is easy to implement in a computer and reaches the optimal solution with less than 50 iterations.

EFEITOS DO MÉTODO DE TREINAMENTO CÍCLICO SOBRE A GINÁSTICA AERÓBICA

ABSTRACT Introduction: The results of the exercises provide an important parameter for evaluating the impact of aerobic activities on athletes. Cyclic training is believed to perform better due to its combination of functional movements. Objective: Study how cyclic training affects fitness in the performance of aerobic gymnastic movements in its practitioners. Methods: 90 athletes practicing aerobic gymnastics were selected, and randomly divided into experimental and control groups, for a 9-week experiment. While the control group practiced the daily exercises, the experimental group added a cyclic training protocol. Tests were performed before and after the intervention to measure any variation in the athletes' fitness. Results: The rate of ground weight lifting in one minute in the experimental group increased from 16.72±4.98 to 18.37±4.16, the number of lifts per minute was increased from 38.56±8.50 to 39.38±7.35, the number of rope jumps in one minute also increased from 149.90±14.67 to 158.30±11.52, and the gain in the exercise of vertical and horizontal supports in 30 seconds evolved from 16.96±2.21 to 17.33±2.42. The experimental group also achieved significant improvements after the circulation training. In contrast, the changes in the data of both groups in the control group were not as evident as those in the experimental group. Conclusion: The combination of cycling and daily training can effectively improve the functional performance of aerobic gymnasts. Level of evidence II; Therapeutic studies -investigation of treatment outcomes.

Biomechanical comparison of ulnar collateral ligament reconstruction with single-tunnel proximal suspensory fixation versus modified docking technique

Despite technical advancement, elbow ulnar collateral ligament (UCL) reconstruction is a challenging procedure due to the limitations regarding the challenging tunnel placement and potential injury to the ulnar nerve. Furthermore, current techniques for reconstruction and repair are inferior functionally and biomechanically when compared to native UCL tissue. A modified docking technique using a single-tunnel proximal suspensory fixation may reduce complications and potentially provide a technique for UCL reconstruction that is biomechanically superior. Decreasing the number of bone tunnels decreases the number of places that bone tear through could occur. The purpose was to evaluate and compare the biomechanical performances for 2 elbow UCL reconstruction techniques: (1) standard docking technique (SD) and (2) a proximal single tunnel (PST) technique using a suspensory fixation. We hypothesized that the PST technique would be biomechanically superior to the SD technique. Twelve matched pairs of cadaveric elbows were dissected and fixed at 70 degrees for biomechanical testing. Gracilis grafts were used for a docking reconstruction and the modified reconstruction with a PST suspensory fixation. A cyclic valgus torque protocol was used to precondition specimens for either reconstruction technique and the ulnohumeral gapping was then assessed. Following gapping measurements, postsurgical specimens underwent a valgus rotation applied at a rate of 5°/s until the anterior band of the UCL failed or fracture occurred. Ultimate load to failure, stiffness, and mode of failure were recorded. There were no statistical differences between the two groups. Mean rotational stiffness of the SD (2.3±0.6 Nm/deg) compared to the PST (1.9±0.7 Nm/deg) (P=.41) and mean ultimate failure torque of the SD (30.5±9.2 Nm) compared to the PST (30.9±8.6 Nm) (P=.86) were similar. There was also no statistically significant difference (P=.83) when comparing the native UCL ulnohumeral gapping (6.0±2.0 mm) to the mean ulnohumeral gapping of the SD reconstruction (6.0±1.8 mm). This study compares the biomechanical strength of elbow UCL reconstructions performed using the SP technique to that of a PST technique. Among all tested parameters, including ultimate failure torque, stiffness, and ulnohumeral gapping, there were no statistically significant differences between the 2 techniques.

Multi-party controlled cyclic hybrid quantum communication protocol in noisy environment

Multi-party controlled cyclic hybrid quantum communication protocol in noisy environment

Successful 3-day lung preservation using a cyclic normothermic ex vivo lung perfusion strategy.

SummaryBackgroundCold static preservation (CSP) at higher temperatures (10°C) has been recently shown as an optimal strategy up to 24-36h of preservation. Here, we hypothesized that alternating 10°C static storage with cycles of normothermic ex vivo lung perfusion (EVLP) would provide conditions for cellular “recharge”, allowing for multi-day lung preservation.MethodsDonor lungs from male Yorkshire pigs were preserved using 10°C CSP with two cycles of 4h EVLP. After a total of 3 days of preservation, a left lung transplant was performed followed by 4h of graft evaluation. As controls, 2 lungs were preserved solely with continuous 10°C preservation for 3 days and transplanted.FindingsFor animals receiving lungs preserved using a cyclic EVLP protocol, lung function and histological structures were stable and the recipient systemic partial pressure of oxygen/fraction of inspired oxygen (P/F Ratio) after excluding the contralateral lung was 422 ± 61 mmHg. In contrast, lungs preserved solely in continuous cold static storage at 10°C for 72h developed massive lung failure, resulting in recipient death. Metabolomic analysis revealed that EVLP plays a critical role in the re-vitalization of key central carbon energy metabolites (Glucose, Succinate, N-Acetyl Aspartate) and reducing the expression of the inflammasome activation marker CASP1.InterpretationIn conclusion, we demonstrate for the first time the feasibility of 3-day lung preservation leading to excellent early post-transplant outcomes. The thoughtful combination of cold storage (10°C) and intermittent EVLP can open new opportunities in organ transplantation.FundingThis work was supported by the UHN Foundation (Grant#1013612).

Local dynamic stability of the trunk after prolonged seating with axial load

Fatigue from prolonged seating with an axial load on the trunk may impair neuromuscular control and spine stability which may elevate risk of low back pain (LBP) for dynamic tasks following seating. The objective of this study was to assess local dynamic trunk stability using the maximum Lyapunov exponent (λMAX) with corresponding coactivation patterns to understand possible effects from prolonged seating. An increase in λMAX would indicate decreased stability. Twenty participants (10 male, 10 female) performed a controlled, cyclic sagittal flexion task at 40 cycles per minute before and after three hours of seating in a simulated helicopter-seating environment with a weighted vest. A statistically significant decrease was seen in λMAX (bits/s) (Pre-Test = 0.654 ± 0.172; Post-Test = 0.829 ± 0.268, p = 0.002), trunk cumulative coactivation index (unitless/s) (Pre-Test = 1.71 ± 0.97; Post-Test = 1.59 ± 0.96, p = 0.0095), and abdominal activation (normalized) (Pre-Test = 0.46 ± 0.17, Post-Test = 0.41 ± 0.18, p = 0.0146) post-seating exposure. Trunk extension was reduced (∼4°, p = 0.0004) during the post-seating cyclic test with slight corresponding increases in flexion. This study provides evidence of potential effects of fatigue from prolonged seating to neuromuscular control, which may have implications for occupations requiring highly dynamic tasks after prolonged seated postures. Future studies would repeat the tests with dynamic environments (i.e., vibration), test the cyclic flexion protocols with different seating interventions, and continue to test the approach to develop a tool to assess back impairment or intervention effectiveness.

Chemomechanics of Rechargeable Batteries: Status, Theories, and Perspectives.

Chemomechanics is an old subject, yet its importance has been revived in rechargeable batteries where the mechanical energy and damage associated with redox reactions can significantly affect both the thermodynamics and rates of key electrochemical processes. Thanks to the push for clean energy and advances in characterization capabilities, significant research efforts in the last two decades have brought about a leap forward in understanding the intricate chemomechanical interactions regulating battery performance. Going forward, it is necessary to consolidate scattered ideas in the literature into a structured framework for future efforts across multidisciplinary fields. This review sets out to distill and structure what the authors consider to be significant recent developments on the study of chemomechanics of rechargeable batteries in a concise and accessible format to the audiences of different backgrounds in electrochemistry, materials, and mechanics. Importantly, we review the significance of chemomechanics in the context of battery performance, as well as its mechanistic understanding by combining electrochemical, materials, and mechanical perspectives. We discuss the coupling between the elements of electrochemistry and mechanics, key experimental and modeling tools from the small to large scales, and design considerations. Lastly, we provide our perspective on ongoing challenges and opportunities ranging from quantifying mechanical degradation in batteries to manufacturing battery materials and developing cyclic protocols to improve the mechanical resilience.

Asymmetric cyclic controlled quantum teleportation by using a quantum channel composed of six G states

In the existing research on cyclic teleportation protocols, it is generally discussed that the teleportation of single particle, two particle unknown quantum states with symmetrical structure or asymmetric special unknown quantum states (such as GHZ state) with three or four participants. In contrast, the scheme proposed in this paper has universality and stronger practicability. In this paper, we propose a novel scheme of asymmetric cyclic controlled teleportation. In our scheme, Alice can teleport an arbitrary single-qubit entangled state to Charlie, Charlie can teleport an arbitrary three-qubit entangled state to Bob and at the same time Bob can teleport an arbitrary two-qubit entangled state to Alice under the control of a controller David. It only needs Bell measurement and local unitary operation, and can realize three-party cyclic transmission with probability 1 by using a quantum channel composed of any six of the 16 G states.

Influence of high cyclic ambient temperature and water drinker design on growth performance and water disappearance of growing-finishing pigs.

The objective of this study was to determine effects of room temperature and drinker design on growth and water disappearance of growing-finishing pigs (26.9 ± 3.67 to 130.9 ± 5.10 kg live body weight). A split-plot design was used with a 2 × 2 factorial arrangement of treatments: Room Temperature (RT) [Thermoneutral (TN) vs. High (HI); main plot], Drinker Design (DD; Nipple vs. Cup; sub-plot). A total of 316 pigs were used, housed in 32 pens in 4 rooms (8 pens/room; 7 pens of 10 pigs and 1 pen of 9 pigs). Two rooms were on each RT treatment. Room temperature for the TN treatment was constant throughout each day but decreased from 24°C at the start to 20°C and 18°C on d 14 and 45 of the study period, respectively. For the HI treatment, a single, cyclic RT protocol was used throughout the study (30°C from 08:00 to 19:00 h and 20°C from 20:00 to 07:00 h, with 1-h transition periods). Pens had fully-slatted concrete floors and 1 feeder and drinker (either nipple or cup); floor space was 0.67 m2/pig. Pigs had ad libitum access to standard corn-soybean diets, formulated to meet or exceed NRC (2012) nutrient requirements. Water disappearance was measured using a meter fitted to the water line supplying each drinker. There were no interactions (P > 0.05) between RT and DD treatments. Drinker Design did not affect (P > 0.05) growth performance; water disappearance was 7.3% greater (P ≤ 0.05) for Nipple than Cup drinkers. Compared to the TN treatment, the HI treatment had no effect (P > 0.05) on gain:feed ratio, but resulted in lower (P ≤ 0.05) average daily gain (6.5%) and average daily feed intake (5.5%) and greater (P ≤ 0.05) average daily water disappearance (16.8%). These results suggest that both drinker design and RT can affect water disappearance, and that the high, cyclic RT regime used reduced growth performance of growing-finishing pigs. Further research is needed to determine the contribution of water intake and wastage to treatment differences in water disappearance.

Folding Free Energy Determination of an RNA Three-Way Junction Using Fluctuation Theorems.

Nonequilibrium work relations and fluctuation theorems permit us to extract equilibrium information from nonequilibrium measurements. They find application in single-molecule pulling experiments where molecular free energies can be determined from irreversible work measurements by using unidirectional (e.g., Jarzynski’s equality) and bidirectional (e.g., Crooks fluctuation theorem and Bennet’s acceptance ratio (BAR)) methods. However, irreversibility and the finite number of pulls limit their applicability: the higher the dissipation, the larger the number of pulls necessary to estimate G within a few . Here, we revisit pulling experiments on an RNA three-way junction (3WJ) that exhibits significant dissipation and work-distribution long tails upon mechanical unfolding. While bidirectional methods are more predictive, unidirectional methods are strongly biased. We also consider a cyclic protocol that combines the forward and reverse work values to increase the statistics of the measurements. For a fixed total experimental time, faster pulling rates permit us to efficiently sample rare events and reduce the bias, compensating for the increased dissipation. This analysis provides a more stringent test of the fluctuation theorem in the large irreversibility regime.

High-strength steel deep H-shaped and box columns under proposed near-fault and post-earthquake loadings

This paper presents the seismic evaluation of high-strength steel first-story columns in a seven-story dual system, composed of a special moment-resisting frame (SMRF) and buckling-restrained braced frame (BRBF), in near-fault and post near-fault earthquakes. Nonlinear time history analyses were conducted on the frame to develop loading protocols that represent seismic demands on the first-story columns in the dual system. The proposed near-fault displacement protocol has a large displacement pulse from -2 to +4% drift, followed by small displacement cycles oscillated at a residual drift of 2.5%. The proposed far-field displacement protocol is an increasingly cyclic displacement protocol with one cycle after a drift of 2%. Two built-up H-shaped column specimens (HC-20-B and HC-20-C) and two built-up box column specimens (HBC-40-B and HBC-40-C), representing the first-story columns in the dual system, are tested under constant axial force (0.2Py or 0.4Py) and lateral drifts based on the proposed loading protocols. These specimens that satisfy the compactness requirement of highly ductile members in AISC 341-16 (2016) show acceptable seismic performance under the near-fault earthquake loading. However, the flexural strength of HC specimens decreases with increasing drift, and that of HBC specimens increases without strength degradation. The HBC specimens can perform well in the subsequent near-fault or far-fielding earthquake loading, which is not the case for the HC specimens due to significant local buckling. The NIST (2017) backbone curve reasonably predicts the test envelope of the HC specimens, but significantly underestimates the test envelope of the HBC specimens.

Microwave-Free Dynamic Nuclear Polarization via Sudden Thermal Jumps.

Dynamic nuclear polarization (DNP) presently stands as the preferred strategy to enhance the sensitivity of nuclear magnetic resonance measurements, but its application relies on the use of high-frequency microwave to manipulate electron spins, an increasingly demanding task as the applied magnetic field grows. Here we investigate the dynamics of a system hosting a polarizing agent formed by two distinct paramagnetic centers near a level anticrossing. We theoretically show that nuclear spins polarize efficiently under a cyclic protocol that combines alternating thermal jumps and radio-frequency pulses connecting hybrid states with opposite nuclear and electronic spin alignment. Central to this process is the difference between the spin-lattice relaxation times of either electron spin species, transiently driving the electronic spin bath out of equilibrium after each thermal jump. Without the need for microwave excitation, this route to enhanced nuclear polarization may prove convenient, particularly if the polarizing agent is designed to feature electronic level anticrossings at high magnetic fields.

Experimental assessment of the behavior of expanded glass lightweight reinforced concrete walls

Structural lightweight concrete (LWC) can significantly reduce the dead loads of reinforced concrete (RC) structures and therefore the associated seismic forces. A new LWC was made using expanded glass as lightweight aggregate (LWA), which is comparatively much lighter than conventional LWAs, and might lead to different performance in lightweight RC elements. An experimental study was conducted to evaluate the structural behavior of expanded glass LWC RC walls. Two types of RC walls were built and tested under cyclic displacement protocol: slender confined and squat unconfined walls. For each type of wall, four specimens were considered: two with LWCs with fc′ of 30 and 40 MPa (i.e., L30 and L40) and densities of 1200 and 1700 kg/m3, respectively; and two with normal weight concretes (NWC) with the same specified strengths acting as control specimens (i.e., N30 and N40) and a density of about 2400 kg/m3. These walls were analyzed in terms of yield drifts and strengths, maximum drifts and strengths, ductility and energy dissipation. Results show that slender confined walls made with L30 mixture showed reductions in ductility and energy dissipation of about 56 and 34%, respectively when compared to N30 specimens. Meanwhile, L40 specimens showed the same tendency, but with smaller reductions compared to N40 of about 36% of ductility and 10% of energy dissipation. In squat unconfined walls, a significant reduction of strength was observed for both types of LWCs, although a bigger difference was observed in L30 concrete. Overall, expanded glass LWC showed promising structural behavior, especially L40 mixture, which presented relatively small differences compared to its NWC counterpart and had only 70% of its unit weight.

Characterization of glial responses in Alzheimer’s disease with cyclic multiplex fluorescent immunohistochemistry and machine learning

Aβ plaques and neurofibrillary tangles in Alzheimer's disease (AD) are associated with reactive astrocytes and microglia. Recent single nuclei RNA-seq studies have reported several transcriptomic phenotypes or states of these glial cells in normal aging and AD. We tested whether multiple astrocyte and microglia states can be detected in human postmortem brain sections from cognitively healthy control and AD subjects using a novel cyclic multiplex fluorescent immunohistochemistry protocol. Single formalin-fixed paraffin-embedded sections from the temporal association cortex (BA38) of n=7 AD and n=7 control individuals were subjected to 8 cycles of multiplex fluorescent immunohistochemistry, totaling 16 primary antibodies (astrocytes: ALDH1L1, EAAT1/GLAST, EAAT2/GLT-1, GFAP, glutamine synthetase [GS], TSPO, vimentin, and YKL-40; microglia: CD68, ferritin, IBA1, MHC2, TMEM119, and TSPO; neurons: HuC/D; and Aβ/phospho-tau). Between successive cycles, we scanned sections in an epifluorescence microscope, denatured/stripped antibodies, and quenched remaining fluorescence. Our analysis pipeline consisted of: (1) image alignment and co-registration across cycles; (2) background subtraction; (3) manual annotation of individual ALDH1L1+ astrocytes and IBA1+ microglia; (4) local thresholding and segmentation, resulting in 5,172 astrocytic and 6,226 microglial profiles; and (5) unsupervised spectral clustering on the normalized intensity values for the above combinations of markers. We identified three broad phenotypes of astrocytes and microglia: "homeostatic," "intermediate," and "reactive." Homeostatic and reactive glia were predominant in control and AD subjects, respectively, whereas intermediate were equally distributed across both groups. Compared to homeostatic, reactive astrocytes contain substantially higher GFAP and YKL-40 levels, modestly elevated vimentin and TSPO as well as EAAT1/GLAST, and reduced GS. Intermediate astrocytes are defined by markedly increased EAAT2/GLT-1, moderately increased GS, and intermediate GFAP and YKL-40 levels. Relative to homeostatic, reactive microglia show increased expression of all markers, including surprisingly TMEM119, whereas intermediate microglia exhibit increased ferritin and TMEM119 as well as intermediate CD68 levels. Cyclic multiplex fluorescent immunohistochemistry allows the deep phenotyping of glia at single-cell resolution in postmortem brain specimens to identify distinct states in health and disease. Besides the homeostatic and reactive, we identified a novel "intermediate" state of both astrocytes and microglia, which may represent a resilience mechanism or, alternatively, a transitional state between homeostatic and reactive.

Energy harvesting from anisotropic fluctuations.

We consider a rudimentary model for a heat engine, known as the Brownian gyrator, that consists of an overdamped system with two degrees of freedom in an anisotropic temperature field. Whereas the hallmark of the gyrator is a nonequilibrium steady-state curl-carrying probability current that can generate torque, we explore the coupling of this natural gyrating motion with a periodic actuation potential for the purpose of extracting work. We show that path lengths traversed in the manifold of thermodynamic states, measured in a suitable Riemannian metric, represent dissipative losses, while area integrals of a work density quantify work being extracted. Thus, the maximal amount of work that can be extracted relates to an isoperimetric problem, trading off area against length of an encircling path. We derive an isoperimetric inequality that provides a universal bound on the efficiency of all cyclic operating protocols, and a bound on how fast a closed path can be traversed before it becomes impossible to extract positive work. The analysis presented provides guiding principles for building autonomous engines that extract work from anisotropic fluctuations.

Co‐Electrodeposition of Nanostructured Ce‐NiOx on Stainless‐Steel Substrates for the Oxygen Evolution Reaction under Alkaline Conditions

AbstractThe development of cost‐effective catalysts that can be fabricated at scale for electrochemical water oxidation is an ongoing challenge. Here it is shown that stainless‐steel AISI316 is an appropriate support electrode for a co‐electrodeposited Ni‐CeOx catalyst for the oxygen evolution reaction (OER) under alkaline conditions. Optimal OER performance is achieved via a cyclic voltammetric deposition protocol rather than constant potential deposition for the catalyst layer. An overpotential of 300 mV at a current density of 10 mA cm−2 is recorded with a Tafel slope of 43 mV dec−1 while the catalyst also demonstrates long‐term stability. It is also found that the catalyst layer changes significantly after the OER. This includes changes to the catalyst morphology, distribution of oxidation state, and speciation as well as the transformation from an entirely amorphous material into one containing crystalline regions. This simple one‐step electrodeposition process on a cost‐effective substrate should, in principle, facilitate the fabrication of low‐cost electrolyzers.

Cyclic Behavior of Tubular Steel Columns with High Yield‐to‐Tensile Strength Ratio under Asymmetric Loading Protocols

AbstractThis paper investigates the cyclic behavior of steel columns subjected to single‐sided cyclic loading protocols driven by residual deformations. First, nonlinear time‐history analyses are performed to steel framed structures using a set of repeated earthquakes. Then, based on the dynamic analysis results, a set of single‐sided loading protocols is developed to envelop the asymmetric seismic behavior of the examined frames. The developed protocols are used to identify the new single‐sided capacity margins of steel columns in terms of strength and ductility as well as evaluate the potential of using novel high‐strength materials. In this paper: (a) the new asymmetric loading protocols are proposed based on the seismic behavior of three medium‐rise frame buildings with different beam‐to‐column strength ratios (i.e. Mpc/Mpb) which are analyzed with the aid of the finite element analysis (FEA) software ABAQUS; (b) a computational databank of the inelastic responses of square tubular steel columns with high yield‐to‐tensile (YT) strength ratio is developed by subjecting column FEA models with various width‐to‐thickness ratio and axial loads to both conventional and asymmetric cyclic loading protocols. Due to the asymmetrical nature of the cyclic protocols, a lower post‐peak strength deterioration was observed in columns that enables the definition of new, extended, ductility capacity margins. The ductility capacity ratios under the asymmetric loading protocols were found to be 1.15 to 1.71 higher than those obtained under the conventional protocols enabling the use of high‐strength steels in steel columns of smaller width‐to‐thickness ratio.

Comparison Between Two Types of Seismic Tests of Racking Systems

AbstractThis paper is the result of both experimental and numeric analyses on pallet rack components. Two cyclic testing protocols for beam‐end connectors of adjustable racking systems are compared; such experiments are named as “code type” and “Castiglioni”. Both protocols share the same test mock‐up: an assembly of a doubly‐pinned upright segment with a cantilever beam specimen. These tests consist in an up‐to‐failure increasing push‐pull process at the free beam end. In the “code type” test, the imposed displacement loops are centered around zero; conversely, in the “Castiglioni” tests, both upward and downward displacement segment runs are centered around a vertical static equilibrium situation (to take the gravitational load into account). The “code type” test is expected to result in a higher number of cycles than the “Castiglioni” one because of the two following features of the latter: (i) the gravitational load is always present, thus resulting in a higher demanding test, and (ii) the failure point is precisely predefined and usually produced before the total breakdown. This paper describes and compares experiments using both protocols. Additionally, these tests are numerically simulated.

Data-driven classification of elementary rearrangement events in silica glass

Reliable classification and prediction of elementary rearrangement events is a crucial step towards a profound understanding of the mechanical behavior of silica glass. Using various cyclic athermal quasistatic shear deformation protocols, we detect angle-changing and bond-breaking events in silica glass, both of which do or do not recover within a defined deformation protocol. We show in this contribution that data-driven approaches using rigorous statistical analyses and polynomial regression provide valuable insights into the mechanics of the marginally stable strain state of silica glass. We classify if a particular event recovers within a defined deformation protocol with up to 90% accuracy and predict the recovering strain with up to 95% accuracy.

Experimental study of the shear behaviour of floor diaphragms in light steel residential buildings

Steel housing solutions made of thin-walled cold-formed steel profiles (CFS) appear to be competitive in seismic areas because of their light weight and the associated reduced mass. This non-negligible advantage on top of their competitive costs and the ease with which they are built have made this type of building popular. In addition, several in-depth studies into the lateral response of shear walls have been carried out in recent years in order to analyse the potential of these structural systems. However, little attention has been paid to the behaviour of floor diaphragms and to their contribution to the overall building response. In an attempt to address this issue, the University of Trento has conducted research into the response of CFS floor systems subjected to in-plane shear loading, as part of a broader research project aimed at the development of a residential building system made of CFS profiles. This involved testing six types of floors featuring two different beam systems and three different types of deck, using monotonic and cyclic protocols. The results of the experiments provide a background to FE model calibration, simulating both the floor components and the whole floor. In this paper, the main features and outcomes of these tests are presented and discussed.