Springer Science and Business Media LLC

This study investigates the pressure-drop behaviour associated with airflow through bulk and structurally tailored multi-layered, open-cell porous Inconel structures over a wide airflow velocity range (0–50 m s−1). The effect of airflow velocity on the pressure-drop behaviour as a function of the sample thickness is presented and related to the flow behaviour corresponding to the relevant flow regimes (Darcy, Forchheimer, Turbulent and Post-turbulent). Entrance effects are highlighted as a source of the pressure-drop increase for porous structures with air gaps, regardless of their sizes, as long as they are larger than those generated by loosely-stacked structures. The pressure-drops for gapped porous structures and the mathematical-summation of the pressure drop for the corresponding individual components, were in very good agreement, at lower airflow velocities. The potential for mass-efficient porous structures, providing a high pressure-drop, was demonstrated using multiple thin porous laminates separated by air gaps.

Mesoporous silica SBA-15 was synthesized using H3PO4 and functionalized with ethylendiaminopropyltrimethoxysilane (H2N–(CH2)2–NH–(CH2)3–) by grafting method. A variety of transition metals such as Co and Mn have been coordinated with amine-functionalized silica SBA-15. The materials have been characterized by XRD, FT-IR, BET, TGA, 13C-NMR, DR UV–Vis, atomic absorption spectroscopy (AAS) and back titration using NaOH (0.1 N). The catalytic performance of obtained catalyst was determined for hydroxylation of benzene using H2O2 as oxidant in the presence of O2 atmosphere. At optimized conditions, the Mn-amine-functionlized mesoporous silica SBA-15 exhibited high catalytic activity at room temperature in the absence of solvent.

We study theoretically the properties of CdS clusters in zeolite Y. We first study free space CdS clusters to establish which geometry is preferred without the influence of the zeolite cage. We next investigate the maximum number of CdS basic units in the supercage of zeolite Y, and the possibility of O substitution for S of (CdS) clusters.

Flexible pressure sensor plays a crucial role in wearable devices since it converts the physical signals of human motions into electrical signals. Among various pressure sensors, foam-based pressure sensors received great attention due to their excellent flexibility, low weight, and pressure resistance. However, the sensitivity of the foam-based pressure sensor is still not large enough, and the sensing range is also urged to be further improved. Herein, we proposed a high-performance foam-based pressure sensor composed of polydimethylsiloxane (PDMS), multi-walled carbon nanotubes (MWCNT), and nanofibers (FIBER). The PDMS/FIBER@MWCNT foam-based pressure sensor possessed outstanding sensitivity up to 4.07 kPa− 1 and a wide sensing range of 0–70 kPa. The pressure sensor also presented excellent linearity during 0–20 kPa and 20–70 kPa, respectively. And 2000 cyclic compression tests shown good cyclic stability. Meanwhile, the pressure sensor worked efficiently in monitoring subtle and large human motions, such as finger bending, wrist bending, throat vocal signals, and various pressures. In addition, the pressure sensor owned significant discrimination and high efficiency against different pressure, which is beneficial in human complex motion monitoring and signal analysis of wearable devices. Consequently, the PDMS/FIBER@MWCNT foam-based pressure sensor may possess promising prospects and potential in the applications of artificial electrical skin and wearable devices.

Over the years, as the economy has grown, numerous new materials have been developed to replace traditional ones. Among these materials, aerogels have become a topic of intensive research. However, the growth of the economy has also had negative impacts on the natural environment, particularly in industries like automotive and energy, which generate a significant amount of waste tire and coal ash. To address these problems, our research has been focused on synthesizing an advanced aerogel using waste tire rubber powder (WTRP) and coal ash (CA), which not only helps to solve the dual problems of the environment but also produces a green material with high applicability. The resulting aerogel has an ultra-low density (0.055 g/cm3) and high porosity (95.6%), making it an excellent insulator with a thermal conductivity of 0.027 W/m.K. Additionally, the aerogel exhibits significantly enhanced rigidity, with a Young modulus of Eavg = 1.206 MPa. Furthermore, the composite aerogel also possesses a good noise reduction coefficient (NRC) of 0.414. The exceptional properties of the aerogel suggest that it holds great promise as a new generation of sustainable, effective, and low-cost materials for thermal and sound insulation.

Highly ordered, conical-pore anodic alumina (AAO) membranes with interpore distance (D c ) between ca. 530 and 620 nm and thickness ranging between 2.4 and 7.8 μm, were produced. In the fabrication process aluminum surface was first pre-patterned by the anodization in etidronic acid solution. Then, the regular arrays of Al concaves were used as nucleation sites to grow AAO during the second anodization, which was carried out in highly concentrated citric acid solution (20 wt%) and at relatively high temperature (33–35 °C). The conical pore shape was engineered by a multistep process combining anodization in the citric acid electrolyte and the subsequent chemical pore broadening in phosphoric acid solution. The morphological analyses has revealed that the geometrical parameters of the Al concaves were successfully transferred to the AAO membranes. Furthermore, FTIR spectra analysis confirmed that the electrolyte species, such as phosphonate and citric ions, are being embedded into the AAO framework during the anodization. The graded-index structure formed in AAO can be used for a production of antireflective coatings operating in a broad spectral range.