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•Optimization study based on the maximum activation of latent heat fusion.•Optimization of PCM location, melting temperature (Tm) and thickness (L) for Turkey.•Investigation of energy ...saving, decrement factor and time lag.•Optimum Tm and L vary 6–34 °C and 1–20 mm depending on climatic conditions.•Up to 13.3 h increment in time lag and 18% of energy saving can be obtained.
Integration of the phase change materials (PCM) into the external building walls is an efficient method for reduction of energy consumption and regulation of energy demands due to increasing thermal inertia of the walls. This study aims to reveal the contribution of latent heat to the thermal performance of the wall and to determine the location, thickness and melting temperature of PCM for the maximum exploitation of latent heat for different climatic conditions. A comparative study is carried out for the wall coupled with PCM and the wall with Phase Stabilized PCM (PSM) to reveal the improvement provided by the latent heat. The influence of location, fusion temperature and layer thickness of PCM on energy saving, decrement factor and time lag was examined. The annually optimized PCM fusion temperature and layer thickness which utilizes the latent heat at maximum level considering both heating and cooling loads are determined for three cities of Turkey. The computed results show that the monthly optimized PCM melting temperature and PCM layer thickness vary from 6 to 34 °C, from 1 to 20 mm depending on climatic conditions. It was concluded that an optimization study should be conducted in order to prevent PCM behaves like PSM.
•The Beam Truss Model is validated for analysis of RC coupled walls.•To enhance the capabilities of the BTM is considered bond-slip and dowel action.•Force – Displacement response of RC coupled walls ...is well captured by the EBTM.•The EBTM can capture sliding shear failures in coupling beams.•The leading pier carries most of the base shear in the coupled walls.
The use of an enhanced version of the Beam-Truss Model proposed in a previous study to compute the nonlinear response of reinforced concrete coupled walls is discussed in this paper. The results of the cyclic tests of two seven-story one-quarter scale coupled walls tested in New Zealand are used for model validation. Except for the coupling beams, the specimens were identical. One of the specimens (Wall A) had a conventional arrangement of reinforcement in the coupling beams, whereas the other (Wall B) had beams with diagonal bars. Specimen Wall A showed lateral force–displacement response degradation after reaching a 1.6% roof drift ratio. The degradation in specimen Wall A was due to sliding shear of the beams. Specimen Wall B exhibited stable hysteretic response throughout the test.
The authors use two kinds of Beam-Truss Models and compare computed and measured key responses in these tests. Computed responses, measured and not measured in the tests, are also compared with the results of Nonlinear Truss Models reported in the literature.
This paper shows that the relatively simple and computational-efficient Beam-Truss Models predicted well important aspects of the response, such as the lateral force–displacement envelope, the sliding shear of the coupling beams in specimen Wall A and the ductile behavior of specimen Wall B.
The design of complex, competing effects in magnetic systems-be it via the introduction of nonlinear interactions
, or the patterning of three-dimensional geometries
-is an emerging route to achieve ...new functionalities. In particular, through the design of three-dimensional geometries and curvature, intrastructure properties such as anisotropy and chirality, both geometry-induced and intrinsic, can be directly controlled, leading to a host of new physics and functionalities, such as three-dimensional chiral spin states
, ultrafast chiral domain wall dynamics
and spin textures with new spin topologies
. Here, we advance beyond the control of intrastructure properties in three dimensions and tailor the magnetostatic coupling of neighbouring magnetic structures, an interstructure property that allows us to generate complex textures in the magnetic stray field. For this, we harness direct write nanofabrication techniques, creating intertwined nanomagnetic cobalt double helices, where curvature, torsion, chirality and magnetic coupling are jointly exploited. By reconstructing the three-dimensional vectorial magnetic state of the double helices with soft-X-ray magnetic laminography
, we identify the presence of a regular array of highly coupled locked domain wall pairs in neighbouring helices. Micromagnetic simulations reveal that the magnetization configuration leads to the formation of an array of complex textures in the magnetic induction, consisting of vortices in the magnetization and antivortices in free space, which together form an effective B field cross-tie wall
. The design and creation of complex three-dimensional magnetic field nanotextures opens new possibilities for smart materials
, unconventional computing
, particle trapping
and magnetic imaging
.
•A novel dual-pinned self-centering coupled CLT shear wall (DSCW) is introduced.•An equivalent energy design procedure (EEDP) is proposed for the DSCW.•The EEDP is used to design the DSCWs of a ...12-story prototype building.•A detailed finite element model of the DSCW is developed.•The seismic performance of the DSCW is assessed using NTHA and IDA.
The use of mass timber structures has considerably grown in recent years. This has increased the demand for sustainable, resilient and high-performance mass timber structural systems. In this paper, a novel self-centering balloon-type cross-laminated timber (CLT) shear wall system, called the dual-pinned self-centering coupled CLT shear wall (DSCW), is proposed for tall building applications. The DSCW consists of two sets of CLT panels that are coupled to one another using self-centering friction dampers and are either pinned at their base or sit on V-shaped truss assemblies. This paper also introduces an equivalent energy design procedure (EEDP) that can be used to design the DSCW such that it meets different performance objectives and roof displacement targets at various earthquake intensities. The procedure was used to design the DSCWs of a 12-story prototype building located in Vancouver (Canada). The DSCWs of the prototype building were numerically modeled and subjected to extensive nonlinear time history and incremental dynamic analyses. The results of these analyses show that the proposed EEDP can be efficiently used to design the DSCW such that it achieves the target roof displacements and performance objectives. The results also show that the DSCWs of the prototype building meet the seismic performance requirements of FEMA P695. Overall, the results presented in this paper demonstrate that EEDP-designed DSCWs have excellent seismic performance and can be safely used in tall buildings located in high-seismicity regions.
•Cyclic loading tests were conducted on self-centering and conventional walls to compare their behaviors.•A tension–compression-coupled disc spring device (TCCDSD) is proposed to install at wall ...corners.•TCCDSD exhibits asymmetric flag-shaped cyclic response without residual displacement.•Mechanical model of TCCDSD is developed.•The self-centering shear wall with TCCDSD shows excellent seismic performance with less residual drift.
A strong self-centering ability and robust ductility have previously been observed in the pseudo-static cyclic loading test conducted on a self-centering shear wall (SCSW) with disc spring devices (DSD). However, the bearing capacity and initial stiffness of the wall are reduced by 34.18% and 53.72% respectively compared with the conventional reinforced concrete wall. Therefore, this paper develops a tension–compression-coupled DSD (TCCDSD) to enhance the bearing capacity of the SCSW. The static cyclic responses of the TCCDSD and the SCSW-TCCDSD are investigated through numerical models. TCCDSD exhibits high first and soft second stiffness values during loading, as well as an asymmetric flag-shaped cyclic response. The mechanical model proposed in the paper demonstrates a high accuracy. Compared with the previous SCSW-DSD, the bearing capacity and initial stiffness of the SCSW-TCCDSD increase by 18.12% and 43.53%, respectively, yet the maximum residual drift ratio only increases by 0.044%. Parametric analysis reveals that increasing the first tensile stiffness or the first compressive stiffness of the TCCDSD can enhance the initial stiffness of the wall. Increasing the second compressive stiffness of the TCCDSD can reduce the residual drift of the SCSW, while a higher second tensile stiffness will result in an obvious residual drift. Moreover, a steel plate reinforcer (SPR) is designed to control the damage of the wall. Despite the reduction damage of the region covered by the SPR, severe shear deformation is concentrated on the interface between the wall and foundation as the SPR is not embedded into the foundation.
The desire of using sustainable materials has reignited the interest in timber-based construction. Researchers and practitioners are developing novel timber-based structural solutions. ...Cross-laminated timber (CLT)-coupled wall is a recently proposed system for potential use in mid- and high-rise timber construction. The National Building Code of Canada, however, does not include this system and, consequently, the seismic force modification factors are not available. This study evaluated the ductility-related force modification factor (R.sub.d) using the FEMA P-695 procedure. Nine archetype buildings were designed considering different design parameters: building storey height, CLT wall configuration, and coupling ratios. Using 30 ground motion records (bi-directional), rigorously selected for seismicity of Vancouver, BC, Canada, incremental dynamic analyses were performed. Collapse margin ratios were calculated to assess the adequacy of the trial Rd factors. Using an over-strength factor of 1.5, R.sub.d = 4 is found to be acceptable for this system.
This article proposes a miniaturized antenna in package (AiP) for 5G millimeter-wave smartphone that incorporates broadside and endfire arrays and supports a dual band covering 28 and 39 GHz. This ...article demonstrates that the proposed AiP is <inline-formula> <tex-math notation="LaTeX">5.8\,\,\text {mm} \times 19\,\,\text {mm} \times 1.122 </tex-math></inline-formula> mm. It is believed that this is the smallest 5G AiP that can support a 10 dBi antenna gain, a 10 dB return-loss bandwidth of 3 GHz, and more than 10 dB isolation for both broadside and endfire arrays. AiP consists of a <inline-formula> <tex-math notation="LaTeX">1\times 4 </tex-math></inline-formula> patch antenna array for broadside radiation and a <inline-formula> <tex-math notation="LaTeX">1 \times 4 </tex-math></inline-formula> dipole antenna array for endfire radiation. To miniaturize the patch antenna elements, a multilayer Reactive Impedance Surface (RIS) is embedded between the patch layer and the ground plane. This multilayer RIS idea greatly fits in 5G PCB-stack-up antennas where each stack-up layer essentially requires certain portion of copper area. For the endfire array antenna, miniaturization with bandwidth improvement is achieved by modifying the vertically bent folded dipole antenna (VBFDA) and adding a tightly coupled T-shape side via wall. The AiP achieves a 10 dB return-loss bandwidth of 26.22 to 29.57 GHz and 35.18 to 41.00 GHz for Multilayer RIS Patch Antenna (MLRPA), and 26.40 to 29.74 GHz and 36.65 to 40.72 GHz for VBFDA. The antenna gain is 11.6 dBi for MLRPA and 10.0 dBi for VBFDA.
Magnetic domain walls are objects whose dynamics is inseparably connected to their structure. In this Letter, we investigate magnetic bilayers, which are engineered such that a coupled pair of domain ...walls, one in each layer, is stabilized by a cooperation of Dzyaloshinskii-Moriya interaction and flux-closing mechanism. The dipolar field mediating the interaction between the two domain walls links not only their position but also their structure. We show that this link has a direct impact on their magnetic-field-induced dynamics. We demonstrate that in such a system the coupling leads to an increased domain wall velocity with respect to single domain walls. Since the domain wall dynamics is observed in a precessional regime, the dynamics involves the synchronization between the two walls to preserve the flux closure during motion. Properties of these coupled oscillating walls can be tuned by an additional in-plane magnetic field enabling a rich variety of states, from perfect synchronization to complete detuning.
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