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In this study, four-point load tests were conducted to evaluate the shear performance of factory-produced precast prestressed concrete hollow core slabs (HCS) assembled on-site. The test specimens were fabricated using compression molding and comprised six samples, with variables being the presence or absence of topping concrete and the shear reinforcement. According to the experimental variables, experiments were conducted using simple support beams to evaluate the shear performance and ultimate strength of HCSs. The results showed that HCSs, regardless of whether they included topping concrete or not, exhibited average values of shear strength more than 10% higher than the factored shear strength specified by concrete structure standards, confirming that these materials satisfy existing design standards. According to current standards, the overall reinforcement length should be increased to meet the minimum shear rebar placement requirements. However, the nominal shear strength of PS concrete hollow slabs exceeded the hollow design, with the ratio of experimental results ranging from 1.26 to 1.87 on average, satisfying the required performance. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the flexural behavior characteristics of prestressed concrete hollow-core slabs (HCSs) through bending experiments. Six specimens were used as variables, both with and without reinforced concrete, in the HCS. A four-point load was applied in the form of a simple support beam to assess the flexural behavior and ultimate strength of HCS. The results demonstrate that, compared to non-reinforced specimens, the reinforced HCS exhibited higher maximum loads and better ductility performance. The experimental outcomes demonstrate that HCS showed an average of 10% higher capacity than the maximum load of the concrete structure standards (KDS 14 20 20, ACI 318-19, and PCI handbook), with or without reinforced concrete, leading to relatively safe predictions. This study's experimental findings are anticipated to aid in evaluating structural safety in a relatively secure way. The findings indicate that the HCS structural system is excellent at sustaining the weight of a structure and ensuring its safety. Additionally, this investigation is anticipated to furnish practical guidance for optimizing the use of HCS systems in structural design and construction. [ABSTRACT FROM AUTHOR]

Stretchable lithium batteries have attracted considerable attention as components in future electronic devices, such as wearable devices, sensors, and body‐attachment healthcare devices. However, several challenges still exist in the bid to obtain excellent electrochemical properties for stretchable batteries. Here, a unique stretchable lithium full‐cell battery is designed using 1D nanofiber active materials, stretchable gel polymer electrolyte, and wrinkle structure electrodes. A SnO2/C nanofiber anode and a LiFePO4/C nanofiber cathode introduce meso‐ and micropores for lithium‐ion diffusion and electrolyte penetration. The stretchable full‐cell consists of an elastic poly(dimethylsiloxane) (PDMS) wrapping film, SnO2/C and LiFePO4/C nanofiber electrodes with a wrinkle structure fixed on the PDMS wrapping film by an adhesive polymer, and a gel polymer electrolyte. The specific capacity of the stretchable full‐battery is maintained at 128.3 mAh g−1 (capacity retention of 92%) even after a 30% strain, as compared with 136.8 mAh g−1 before strain. The energy densities are 458.8 Wh kg−1 in the released state and 423.4 Wh kg−1 in the stretched state (based on the electrode), respectively. The high capacity and stability in the stretched state demonstrate the potential of the stretchable battery to overcome its limitations. [ABSTRACT FROM AUTHOR]

Porous TiO2 nanofibers (PTFs) and dense TiO2 nanofibers (DTFs) were prepared using simple electrospinning for application in dye-sensitized solar cells (DSSCs). TiO2 nanoparticles (TNPs) were prepared using a hydrothermal reaction. The as-prepared PTFs and DTFs (with a fiber diameter of around 200 nm) were mixed with TNPs such as TNP-PTF and TNP-DTF nanocomposites used in photoelectrode materials or were coated as light scattering layers on the photoelectrodes to improve the charge transfer ability and light harvesting effect of the DSSCs. The as-prepared TNPs showed a pure anatase phase, while the PTFs and DTFs showed both the anatase and rutile phases. The TNP-PTF composite (TNP:PTF = 9:1 wt.%) exhibited an enhanced short circuit photocurrent density (Jsc) of 14.95 ± 1.03 mA cm−2 and a photoelectric conversion efficiency (PCE, η) of 5.4 ± 0.17% because of the improved charge transport and accessibility for the electrolyte ions. In addition, the TNP/PTF photoelectrode showed excellent light absorption in the visible region because of the mountainous nature of light induced by the PTF light scattering layer. The TNP/PTF photoelectrode showed the highest Jsc (16.96 ± 0.79 mA cm−2), η (5.9 ± 0.13%), and open circuit voltage (Voc, 0.66 ± 0.02 V). [ABSTRACT FROM AUTHOR]