This study aims to assess the effectiveness of inter-storey isolation structures in reducing seismic responses in super high-rise buildings, with a focus on analyzing the impact of soil-structure interaction (SSI) on the dynamic performance of the buildings. Utilizing the lumped parameter SR (Sway-Rocking) model, which separately simulates the overall displacement of the super high-rise structure and the rotational motion of the foundation, the dynamic characteristic parameters of the simplified model are derived. The natural frequencies of the system are calculated by solving the equations of motion. The study examines the influence of parameters such as soil shear wave velocity and structural damping ratio on the dynamic response of the structure, with particular emphasis on displacement transfer rates. The findings indicate that inter-storey isolation structures are highly effective in reducing displacement responses in super high-rise buildings, especially when considering SSI effects. Specifically, for high-damping inter-storey isolation structures, modal frequencies decrease as soil shear wave velocity decreases. In non-isolated structures, the damping ratio increases with decreasing soil shear wave velocity, whereas for isolated structures, the damping ratio decreases, with a more pronounced reduction at higher damping ratios. Increasing damping significantly reduces inter-storey displacement and damage indices. However, under low shear wave velocity conditions, inter-storey isolation structures may experience increased displacement and damage.

This study presents a novel seismic control system, the Mega-Sub Controlled Structure System (MSCSS), to address vibration control challenges in tall and super-tall buildings under intense seismic excitations. The proposed hybrid VD-TFPB-controlled MSCSS integrates Triple Friction Pendulum Bearings (TFPBs) as base isolators with Viscous Dampers (VDs) between the mega frame and the vibration control substructure, enhancing damping and seismic performance. MSCSS without VD and MSCSS with VD models are established and verified using an existing benchmark. The hybrid VD-TFPB-controlled MSCSS is then developed to evaluate its vibration control response while considering soil-structure interaction (SSI). Numerical analyses with earthquake records demonstrate its superior performance compared to MSCSS without and with VD systems. Nonlinear dynamic analyses reveal that the hybrid system significantly improves vibration control. However, under SSI, increased structural flexibility leads to higher frame stress and more plastic hinges, particularly on soft soil, which amplifies vibrations. Despite these challenges, the hybrid VD-TFPB-controlled MSCSS effectively enhances seismic resilience, offering a robust solution for tall buildings.

Determining the optimal damping value of the isolation system in tall structures is challenging as it requires parametric studies and time-consuming nonlinear time-history analyses. Consequently, the influence of different parameters, such as displacement limitation, on the optimal damping of isolators in tall structures remains unclear. This study aims to investigate the optimal damping of isolators in tall structures under two scenarios: a) changing the displacement capacity of the isolators in proportion to the increase of damping (variable gap); b) maintaining a constant displacement capacity of the isolators as the damping increases (constant gap). The study also explores the influence of two additional parameters on the optimal damping of the isolation system, namely the ratio of isolator to superstructure period (TM/TS) and the soil type. The optimal design procedure is illustrated with reference to a case-study 14-story isolated steel structure with an ordinary concentrically braced frames (OCBF) system, isolated with the triple friction pendulum isolator (TFPI) system. The modified endurance time (MET) method is utilized to analyze the seismic response of the case-study structure under increasing levels of earthquake hazard. The analysis reveals that increasing damping in both constant and variable gap modes can effectively reduce the damage level of the structure. However, the effectiveness of increasing damping is limited and influenced by factors such as soil softness and the TM/TS ratio. The optimal damping values are determined based on the desired performance levels for both structural and nonstructural acceleration-sensitive components.

Highlights What are the main findings? The bast fibers extracted from the second generation of energy crop L. biomass have consistent yield and stable productivity across different seasons; Sida hermaphroditaThe results revealed a favorable moisture content, strength, and toughness, suitable for storage and processing. What are the implications of the main findings? fibers are suitable for use in a wide range of industrial applications, where a combination of lightness, strength, and toughness is required; Sida hermaphroditaAccording to the circular economy principles, a high percentage of side streams after fiber isolation are successfully applied for biofuel production.Highlights What are the main findings? The bast fibers extracted from the second generation of energy crop L. biomass have consistent yield and stable productivity across different seasons; Sida hermaphroditaThe results revealed a favorable moisture content, strength, and toughness, suitable for storage and processing. What are the implications of the main findings? fibers are suitable for use in a wide range of industrial applications, where a combination of lightness, strength, and toughness is required; Sida hermaphroditaAccording to the circular economy principles, a high percentage of side streams after fiber isolation are successfully applied for biofuel production.Abstract Virginia mallow or Sida hermaphrodita (L.) Rusby (SH) is a perennial plant from the Malvaceae family (mallows) that is used for medicinal purposes, reducing soil erosion, cleaning soil, and most recently for energy production. The potential of sustainable lignocellulosic agro-waste is immense as it represents Earth's most abundant organic compound. This paper explores fibers isolated from SH stems, a plant with significant industrial application potential, including technical textiles and biocomposites. The fibers were harvested in January, March, and November of 2020 and in January and March of 2021, and their yield, mechanical properties, moisture content, and density were thoroughly analyzed. The fiber yield showed slight variations depending on the harvest time, with consistent results observed across different years, suggesting stable productivity. The SH fibers demonstrated a favorable moisture content, making them suitable for storage and processing, and their density ranged between 1.52 and 1.58 g/cm3, comparable to that of other natural fibers. According to this research, the best mechanical properties were observed in the winter harvest. Furthermore, the high percentage of solid residue left after fiber extraction shows promise for sustainable utilization, primarily for biofuel production. This study underscores the versatility and sustainability of SH fibers, positioning them as a valuable resource for a wide range of industrial applications.

Geotechnical seismic isolation (GSI) is a new concept that has been proposed recently. The injection of polyurethane into the soil layer (non-intrusive GSI) reduces seismic fragility without altering the original structure, which may provide an effective seismic isolation solution for existing bridge structures. The purpose of this study was to investigate the seismic isolation effect and isolation mechanism of non-invasive GSI applied to existing bridges. First, a noninvasive GSI site modeling method is described based on the results of existing soilpolyurethane resonance column tests and the OpenSees computational platform. Subsequently, a refined dynamic analysis model of site-existing bridge interactions was established by combining the rusting theory. The seismic isolation effect of the non-invasive GSI and its effect on the seismic response of the bridge were explored using a nonlinear dynamic time-course analysis. The results showed that non-invasive GSI soils can change the characteristic period of ground motion, thus reducing the site effect. The seismic isolation effect was positively correlated with the percentage of injected polyurethane. Altering the characteristic period of the site and avoiding as many of the preeminent periods of ground motion as possible is the result of noninvasive GSI. The non-invasive GSI soil layer reduces the structural response and provides seismic isolation throughout the life cycle of corroded piers, and its fragility is significantly reduced. Especially, the old piers have significant seismic isolation effect, effectively limiting serious damage or even collapse under earthquakes. The results of this study provide a reference for noninvasive GSI design of existing bridge structures.

The study of vibration isolation devices has become an emerging area of research in view of the extensive damage to buildings caused by earthquakes. The ability to effectively isolate seismic vibrations and maintain the stability of a building is thus addressed in this paper, which evaluates the effect of horizontal ground excitation on the response of a structure isolated by a coupled isolation system consisting of a non-linear damper (QZS) and a friction pendulum system (FPS). A single-degree-of-freedom system was used to model structures whose bases are subjected to seismic excitation in order to assess the effectiveness of the QZS-FPS coupling in reducing the structural response. The results obtained revealed significant improvements in structural performance when the QZS-FPS system uses a damper of optimum stiffness. A 30% reduction in displacement was recorded compared with QZS alone for two signals, one harmonic and the other stochastic. The response of the QZS-FPS system with soft stiffness to a harmonic pulse reveals amplitudes reaching around eight times those of the pulse at low frequencies and approaching zero at high frequencies. In comparison, the rigid QZS-FPS coupling has amplitudes 0.9 and 3.5 times higher than those of the harmonic signal. Thus, the resonance amplitudes observed for the QZS-FPS system are lower than those reported in other studies. This analysis highlights the performance differences between the two types of stiffness in the face of harmonic pulses, underlining the importance of the choice of stiffness in vibration management applications. The stochastic results show that on both hard and soft soils, the new QZS-FPS system causes structures to vibrate horizontally with maximum amplitudes of the order of 0.003 m and 0.007 m respectively. So, QZS-FPS coupling can be more effective than all other isolators for horizontal ground excitation. In addition, the study demonstrated that the QZS-FPS combination can offer better control of building vibration in terms of horizontal displacements.

(1) Background: Plastic contamination is on the rise, despite ongoing research focused on alternatives such as bioplastics. However, most bioplastics require specific conditions to biodegrade. A promising alternative involves using microorganisms isolated from landfill soils that have demonstrated the ability to degrade plastic materials. (2) Methods: Soil samples were collected, and bacteria were isolated, characterized, and molecularly identified. Their degradative capacity was evaluated using the zone of clearing method, while their qualitative and structural degradative activity was assessed in a liquid medium on poly(butylene succinate) (PBS) films prepared by the cast method. (3) Results: Three strains-Bacillus cereus CHU4R, Acinetobacter baumannii YUCAN, and Pseudomonas otitidis YUC44-were selected. These strains exhibited the ability to cause severe damage to the microscopic surface of the films, attack the ester bonds within the PBS structure, and degrade lower-weight PBS molecules during the process. (4) Conclusions: this study represents the first report of strains isolated in Yucat & aacute;n with plastic degradation activity. The microorganisms demonstrated the capacity to degrade PBS films by causing surface and structural damage at the molecular level. These findings suggest that the strains could be applied as an alternative in plastic biodegradation.

To mitigate the metro-induced vertical vibration of the indoor substation structure, this study proposes a gas-spring quasi-zero stiffness air damping isolator (AD-QZSI) with excellent low dynamic stiffness and high-static stiffness characteristics. The working principle and mechanical properties of the AD-QZSI are introduced and studied through theoretical and numerical methods. A model for substation considering soil-structure-equipment interaction is established using the software ABAQUS, its accuracy is validated based on a series of measured data from actual projects, and the AD-QZSI's simulation method and parameter design method are described in detail. The air damper's stiffness ka is integrated into the isolator's mechanical model, theoretically and numerically achieving an accurate simulation of AD-QZSI's nonlinear mechanical properties. The numerical results have an error of less than 5% with the measured data, indicating that the model is able to better capture the actual structure's dynamic characteristics and is reasonable to be employed for subsequent analysis. Numerical results show that AD-QZSI can significantly reduce the structural vertical vibration, and its control effect is better in the whole frequency band, in particular, the effect is also visible in the low-frequency band, indicating that its vibration isolation frequency band is wider than that of traditional QZS isolator. With the vibration source distance increasing, the control effect of AD-QZSI presents a tendency to decrease and then level off, and its vibration isolation gain is weakened by the continuous increase of the damping ratio greater than 0.01. Moreover, the equipment's dynamic amplification factor of the isolated structure decreases significantly. Finally, the proposed AD-QZSI can obtain ideal quasi-zero stiffness characteristics by adjusting the air pressure, and the adopted air damper belongs to the green low-carbon components, featuring great practical value and application prospects.

The damage behaviour of structures depends not only on the superstructure but also on the underlying soil. However, in traditional design, the soil-structure interaction (SSI) effect is often neglected, which can affect the seismic response patterns and the analysis of damping performance. In this study, a finite element model of split-foundation (SF) structures is established, and the SSI effect is simulated using the lumped parameter model (LPM). Simultaneously, we introduce the popular mid-story isolation (MSI) technology in recent years. The seismic response patterns of non-isolated (NI) structures and MSI structures under the influence of SSI effects, as well as the damping performance of MSI, are explored. Additionally, we alter the span form of the structure and analyze the sensitivity of the structure to SSI effects and damping performance, making the research more comprehensive. The results indicate that NI structures are more affected by SSI effects, and the significance of SSI effects increases as the soil becomes softer. MSI is insensitive to the SSI effect experienced by the structure. MSI exhibits good damping performance in SF structures.

The growing accumulation of agricultural waste, particularly groundnut shells, presents significant environmental concerns due to methane emissions and greenhouse gas release from crop residue burning. Groundnut shell powder, a biodegradable byproduct, offers potential as a raw material for bio-nanocomposite films. This study focuses on the development of biodegradable packaging films from groundnut shell powder, evaluating their physicochemical and mechanical properties while optimizing process parameters. Experiments were conducted to optimize the process parameters, viz., shaker time (6, 12, and 18 h), shaker speed (160, 180, and 240 rpm), and concentration of laccase enzyme (80, 100, and 120 mg) to leach out maximum lignin content in short duration. Further, to stop enzymatic reaction, drying time, drying temperature, and storage condition (dark or light) were optimized to minimize the time of operation, maximize cellulose, and minimize lignin content for isolation of cellulose microfibers from peanut shell powder. The biodegradable film from groundnut shell powder was developed by solution casting method. The three types of films, viz., agar powder-based (AG), mixture of agar powder and peanut shell powder (PSP), and mixture of agar powder and cellulose microfiber (CMF), were developed at optimized conditions. The maximum thickness was achieved by the cellulose microfiber-based film. The transmittance value of agar film was lesser than that of CMF film and PSP. The CMF film's water solubility and tensile strength was observed highest in comparison to that of the other two films. CMF and PSP films had a higher opacity value than agar films. Due to the presence of lignin, it was found that PSP loses less weight than CMF film during the soil burial degradation test. Therefore, the findings suggested that CMF film possesses not only improved biodegradability but also superior physical and mechanical properties, which may be suitable for use as a food packaging material.