A facile method to grow V-doped TiO2 hydrophilic layers with nano-sheet morphology

V-doped titania layers with a novel morphology and a rough surface were grown the via micro arc oxidation process in the electrolytes consisting of sodium vanadate under various voltages. Morphological investigations, performed by SEM, revealed that the layers had a sheet-like structure whose average thickness was less than 100 nm depending on the applied voltage. Our XRD and XPS results showed that the layers consisted of anatase, rutile, and vanadia phases with a varying fraction depending on the voltage. Hydrophilicity of the layers was also studied by measuring the water contact angle on their surfaces under ultraviolet and visible illuminations. The layer synthesized under the voltage of 450 V exhibited the highest hydrophilicity.     

Formability Prediction of Two-Layer Sheets Based on Ductile Fracture Criteria

Two-layer sheets which consist of dissimilar metallic components are widely used in various industries. In this paper, formability of Al3105–St14 two-layer sheet is evaluated numerically and experimentally. Freudenthal, Cockroft & Latham, Oh and Brozzo ductile fracture criteria are implemented to predict forming limits in the numerical approach. Numerical FLDs and FLSDs are compared with experimental observations for Al3105–St14 two-layer sheet, and a good agreement is seen. The results show that the prediction of forming limits based on Oh and Brozzo ductile fracture criteria are more accurate than the predictions based on Freudenthal and Cockroft criteria.     

High Ionic Conductivity Motivated by Multiple Ion-Transport Channels in 2D MOF-Based Lithium Solid State Battery

Metal-organic frameworks (MOFs) have been proposed as novel fillers for constructing polymer solid electrolytes based composite electrolytes. However, MOFs are generally used as passive fillers, in-depth revealing the binding mode between MOFs and polyethylene oxide (PEO), the critical role of MOFs in facilitating Li⁺ transport in solid electrolytes is full of challenges. Herein, inspired by density functional theory (DFT) the 2D-MOF with rich unsaturated metal coordination sites that can bind the O atom in PEO through the metal–oxygen bond,  anchor TFSI⁻ to release Li⁺, resulting in a remarkable Li⁺ transference number of 0.58, is reported according well with the experimental results and molecular dynamics (MD) simulation. Impressively, after the introduction of the 2D-MOF, the Li⁺ can rapidly hop along the benzene ring center within the 2D-MOF plane, and the interface between the benzene ring and PEO can also serve as a fast Li⁺ migration pathway, delivering multiple ion-transport channels, which present a high ion conductivity of 4.6 × 10⁻⁵ S cm⁻¹ (25 °C). The lithium symmetric battery is stable for 1300 h at 60 °C, 0.1 mA cm⁻². The assembled lithium metal solid state battery maintains high capacity of 162.8 mAh g⁻¹ after 500 cycles at 60 °C and 0.5 C. This multiple ion-transport channels approach brings new ideas for designing advanced solid electrolytes.     

Improved Cytotoxicity and Induced Apoptosis in HeLa Cells by Co-loading Vitamin E Succinate and Curcumin in Nano-MIL-88B-NH2

One of the strategies for improved therapeutic effects in cancer therapy is combination chemotherapy. In this study, a flexible nano-MOF (Fe-MIL-88B-NH₂) was synthesized in a sonochemical process, then co-loaded with α-tocopheryl succinate (TOS) and curcumin (CCM). The anticancer activity of co-loaded Fe-MIL-88B-NH₂ (Fe-MIL-88B-NH₂/TOS@CCM) against the HeLa cells was compared with that of the single-loaded counterpart (Fe-MIL-88B-NH₂@CCM). MTT analysis indicates improved cytotoxicity of Fe-MIL-88B-NH₂/TOS@CCM. The data from the cell apoptosis assay indicated more apoptosis in the case of the co-loaded nano-MOF. This study indicates the positive effect of the presence of TOS on enhancing the anticancer effect of Fe-MIL-88B-NH₂@CCM to prepare a more efficient drug delivery nanosystem.     

ICT and environmental sustainability: A global perspective

The positive and negative environmental impacts of information and communication technologies (ICTs) are widely debated. In theory, ICT is among the sources contributing to the increasing levels of CO₂ emissions in terms of production of ICT machinery and devices, energy consumption, and recycling of electronic waste. However, ICT is also expected to reduce CO₂ emissions on a global scale by developing smarter cities, transportation systems, electrical grids, industrial processes, and energy saving gains. These two effects work in opposite direction, creating an inverted-U relationship between ICT and CO₂ emissions. The aim of this study is to investigate this non-linear relationship between ICT and CO₂ emissions on a global scale. Given that global warming is a global issue, it is necessary to look at this relationship in countries at all levels of development. To this end, we use a panel data set consisting of 142 economies, split into 116 developing and 26 developed countries, over the period 1995–2010. The results of our empirical study confirm that the relationship between ICT and CO₂ emissions is an inverted U-shaped relationship. Moreover, while for the sample of developing countries, the ICT turning point is well above the mean value, the opposite is true for the sample of developed countries. This implies that many developed countries have already attained the level of ICT development, at which CO₂ emissions decreases as the level of ICT development improves further.     

Analyzing the capacity of wireless ad hoc networks

In this paper we develop analytical closed form expression for the capacity of a wireless ad hoc network. First, for the general case when nodes can adapt their communication rates to the link quality, a proper formulation for the total network capacity is presented based on the cumulative distribution function (CDF) of the signal to interference power ratio (SIR). Then, a closed form expression for this CDF is analytically derived. This closed form is further studied by fitting it to a normal distribution. Afterwards, the capacity of the network is investigated. By examining the effect of the outage threshold, it is shown that in order to obtain a higher capacity, one may use simple non-adaptive transceivers with higher threshold on the received SIR. These results are obtained by conducting analytical and simulation studies.     

High Surface Area MoS2/Graphene Hybrid Aerogel for Ultrasensitive NO2 Detection

A MoS₂/graphene hybrid aerogel synthesized with two‐dimensional MoS₂ sheets coating a high surface area graphene aerogel scaffold is characterized and used for ultrasensitive NO₂ detection. The combination of graphene and MoS₂ leads to improved sensing properties with the graphene scaffold providing high specific surface area and high electrical and thermal conductivity and the single to few‐layer MoS₂ sheets providing high sensitivity and selectivity to NO₂. The hybrid aerogel is integrated onto a low‐power microheater platform to probe the gas sensing performance. At room temperature, the sensor exhibits an ultralow detection limit of 50 ppb NO₂. By heating the material to 200 °C, the response and recovery times to reach 90% of the final signal decrease to <1 min, while retaining the low detection limit. The MoS₂/graphene hybrid also shows good selectivity for NO₂ against H₂ and CO, especially when compared to bare graphene aerogel. The unique structure of the hybrid aerogel is responsible for the ultrasensitive, selective, and fast NO₂ sensing. The improved sensing performance of this hybrid aerogel also suggests the possibility of other 2D material combinations for further sensing applications.     

Enhanced thermal stability by introducing TiN diffusion barrier layer between W and SiC

The combination of W and SiC has many applications such as a hot cell of a thermionic energy converter, nuclear material, and high temperature microelectronics. In this study, a 2 µm thick TiN film is introduced as a diffusion barrier between SiC and W to avoid the inter-diffusion reaction at high temperature. The effect of annealing temperature on the surface morphology and microstructure of the TiN film is studied to explore its high temperature stability. Then 500 nm W film is sputtered on the TiN film to characterize the inter-diffusion and stability of the W/TiN/SiC multilayer at 1100°C by XRD, Raman spectroscopy and cross-sectional EDS mapping techniques. The results indicate that the W/TiN/SiC multilayer is very stable even when heated at 1100°C for 25 hours.