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.     

Comprehensive energy and economic transient analysis of an off-grid hydrogen car-integrated zero energy building

Clean Technologies and Environmental Policy - In this study, for the first time, an off-grid zero-energy building with hydrogen energy storage integrated with two hydrogen cars is simulated and...     

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.     

Trapping Lithium Selenides with Evolving Heterogeneous Interfaces for High-Power Lithium-Ion Capacitors

Transition metal selenides anodes with fast reaction kinetics and high theoretical specific capacity are expected to solve mismatched kinetics between cathode and anode in Li-ion capacitors. However, transition metal selenides face great challenges in the dissolution and shuttle problem of lithium selenides, which is the same as Li-Se batteries. Herein, inspired by the density functional theory calculations, heterogeneous can enhance the adsorption of Li₂Se relative to single component selenide electrodes, thus inhibiting the dissolution and shuttle effect of Li₂Se. A heterostructure material (denoted as CoSe₂/SnSe) with the ability to evolve continuously (CoSe₂/SnSe→Co/Sn→Co/Li₁₃Sn₅) is successfully designed by employing CoSnO₃-MOF as a precursor. Impressively, CoSe₂/SnSe heterostructure material delivers the ultrahigh reversible specific capacity of 510 mAh g⁻¹ after 1000 cycles at the high current density of 4 A g⁻¹. In situ XRD reveals the continuous evolution of the interface based on the transformation and alloying reactions during the charging and discharging process. Visualizations of in situ disassembly experiments demonstrate that the continuously evolving interface inhibits the shuttle of Li₂Se. This research proposes an innovative approach to inhibit the dissolution and shuttling of discharge intermediates (Li₂Se) of metal selenides, which is expected to be applied to metal sulfides or Li-Se and Li-S energy storage systems.