Performance of a multi-story structure with a resilient-friction base isolation system

Complex frequency response functions and excitation-response relations for stationary random process are formulated to estimate responses of multi-story superstructures isolated with resilient-friction base isolation (R-FBI) system. The equivalent linearization technique is also used to linearize the nonlinear governing equations of motion of R-FBI system occurred between the parallel actions of the resiliency of rubber and friction of Teflon-coated plates. In this approach, the spectral density functions for both the relative displacement response and absolute acceleration response of N degrees of freedom systems are derived. The applicability and accuracy of the proposed methodology are examined by comparing the resulting responses obtained from this study with those calculated from time history analysis based method. These two studies demonstrate good agreement in terms of characteristics of peak responses. Extensive sensitivity analysis to find the influence of various important structural parameters on the behavior of structures isolated with R-FBI system is also carried out.     

Flexible time–temperature indicator: a versatile platform for laminated paper-based analytical devices

Time–temperature indicators are devices employed for monitoring thermal history of perishable food products from storage to consumption. As the food industry has opted for intelligent packaging, which also involves thin foldable wrappings, a requirement arises for a flexible device capable of attaching and sensing on a curved product surface. In this study, we have fabricated a distance-based flexible time–temperature indicator (FTTI) by employing electronic cutting machine and through press lamination of thermoplastic films; we have incorporated the FTTI with a unique starting actuation switch made of thin (150 μm) cover glass. Flow profile in 0.45 μm nitrocellulose membrane is measured for oleic, octanoic, and decanoic acids representing test temperatures of 5, 15 and 30 °C, respectively. Results demonstrate the sensor to be robust and flexible with precise responsiveness to oscillating temperature conditions. Further improvement in time-scale is achieved by employing a series of fan-shaped cut channels. This two-dimensional flow increases the device time by 170% in comparison with straight channel and improves scale readability by achieving a linear distance-time relation in the porous membrane. The advantages of low cost, simple design, freedom from equipment, robustness, and flexibility render the FTTI a versatile platform for distance-based diagnostics, food quality control, and environmental monitoring devices.     

A new apartment construction technology with effective CO2 emission reduction capabilities

This construction industry is responsible for over 30% of the total industrial CO₂ emission in Korea, and bearing wall apartment housing represents more than 50% of all housing in Korea. A new multi-residential Modularized Hybrid System (MHS) for construction of apartment housing may reduce the amounts of construction material used as well as the amounts of CO₂ emission. This paper collected and compared data on the CO₂ emission properties of construction materials for bearing wall and new MHS apartments including concrete, reinforcing steels, formwork, and gypsum board. MHS construction techniques reduce CO₂ emission by 25.1% by requiring less concrete and reinforcing steels for slabs and walls that would otherwise be needed in conventional bearing wall structures. This paper also shows that migration to a Rahmen structure utilizing an MHS frame can provide an alternative solution to reducing CO₂ emission.     

An on-chip cache compression technique to reduce decompression overhead and design complexity

This research explores a compressed memory hierarchy model which can increase both the effective memory space and bandwidth of each level of memory hierarchy. It is well known that decompression time causes a critical effect to the memory access time and variable-sized compressed blocks tend to increase the design complexity of the compressed memory systems. This paper proposes a selective compressed memory system (SCMS) incorporating the compressed cache architecture and its management method. To reduce or hide decompression overhead, this SCMS employs several effective techniques, including selective compression, parallel decompression and the use of a decompression buffer. In addition, fixed memory space allocation method is used to achieve efficient management of the compressed blocks. Trace-driven simulation shows that the SCMS approach can not only reduce the on-chip cache miss ratio and data traffic by about 35% and 53%, respectively, but also achieve a 20% reduction in average memory access time (AMAT) over conventional memory systems (CMS). Moreover, this approach can provide both lower memory traffic at a lower cost than CMS with some architectural enhancement. Most importantly, the SCMS is a more attractive approach for future computer systems because it offers high performance in cases of long DRAM latency and limited bus bandwidth.     

Use of laminated mechanical joints with metal and concrete plates for precast concrete columns

This study investigated the structural behavior of a mechanical joint with laminated concrete and metal plates for moment connections which can be used for the rapid erection of reinforced concrete precast columns. A concrete filler plate was placed between the metal column plates to transfer loads and protect nuts threaded with rebars. Nonlinear numerical finite element analyses considering concrete damaged plasticity was also performed to evaluate the load–displacement relationship, plate deformation of the joints with concrete filler plates, and rates of strain increase of the structural components. The influence of the column and concrete filler plates on the rate of strain increase of the structural components attached to the column plates was explored to determine how concrete, rebars, and steel sections, were activated relative to the stiffness of the metal plates. The strain values of structural elements that were attached to plates with sufficient stiffness values were found to be higher than those of the structural elements that were attached to plates with smaller stiffness values. These strains were evident in the nonlinear finite element analyses and experimental investigations. It can be inferred that laminated mechanical plates consisting of metal and concrete plates can be implemented and used to replace conventional precast connections.     

Topoisomerase IIIβ Deficiency Induces Neuro-Behavioral Changes and Brain Connectivity Alterations in Mice

Topoisomerase IIIβ (Top3β), the only dual-activity topoisomerase in mammals that can change topology of both DNA and RNA, is known to be associated with neurodevelopment and mental dysfunction in humans. However, there is no report showing clear associations of Top3β with neuropsychiatric phenotypes in mice. Here, we investigated the effect of Top3β on neuro-behavior using newly generated Top3β deficient (Top3β^−/−) mice. We found that Top3β^−/− mice showed decreased anxiety and depression-like behaviors. The lack of Top3β was also associated with changes in circadian rhythm. In addition, a clear expression of Top3β was demonstrated in the central nervous system of mice. Positron emission tomography/computed tomography (PET/CT) analysis revealed significantly altered connectivity between many brain regions in Top3β^−/− mice, including the connectivity between the olfactory bulb and the cerebellum, the connectivity between the amygdala and the olfactory bulb, and the connectivity between the globus pallidus and the optic nerve. These connectivity alterations in brain regions are known to be linked to neurodevelopmental as well as psychiatric and behavioral disorders in humans. Therefore, we conclude that Top3β is essential for normal brain function and behavior in mice and that Top3β could be an interesting target to study neuropsychiatric disorders in humans.     

Post-yield behavior of fixed steel beams encased in concrete with plastic rotation capability under monotonic loads

Flexural strength calculated based on only curvature at sections shows some inconsistencies at large strains compared with nonlinear finite element analyses which considered damaged concrete plasticity. The prediction of the post-yield behavior of steel–concrete composite structures has been a complex issue, rendering analytically inaccurate prediction of the post-yield deflection of composite beams when plastic flows were not considered. The accurate prediction of the post-yield deformation of composite steel beams encased in structural concrete should account for the strain based on plastic rotation. The plastic rotation is influenced by the inelastic energy dissipation. The post-yield behavior of steel–concrete composite structures is affected by the inclination of diagonal cracks of concrete, and the stiffening effect of concrete tension between cracks. Plastic strain occurring in the steel section also contributes to in-elastic behavior of composite structures. The aim of this study was to idealize plastic flow of steel beams encased in structural concrete at fixed foundation. Plastic flows were calculated by non-linear finite element analysis including the consideration of concrete plasticity. The post-yield deflection was, then, predicted in a manner reflecting plastic deformation. The proposed idealization agreed well with numerical data obtained by means of nonlinear finite element analysis, providing a simplified but reliable procedure for practicing engineers designing composite structures in the inelastic region.