Sharif Digital Repository

The effect of moisture on Shengli lignite breakage behavior and energy efficiency was studied experimentally using a standard Hardgrove mill fitted with a wattmeter. The grinding process concerned both the inputs, namely the occurrence and content of water and instantaneous energy consumption and the outputs, size-reduction and product fineness. Results show that the energy-size reduction process for grinding lignite is markedly influenced by moisture occurrence and content. Removing surface moisture from 37.90% to 16.61% (the air-dried condition) resulted in a slight increase of input energy by 0.04 kWh.t−1 per 10 s. However, with further drying inherent moisture to 0%, the consumed energy... 

Because of the compatibility with tandem devices and the ability to be manufactured at low temperatures, inverted perovskite solar cells have generated far-ranging interest for potential commercial applications. However, their efficiency remains inadequate owing to various traps in the perovskite film and the restricted hole blocking ability of the electron transport layer. Thus, in this work, a wide-bandgap n-type semiconductor, 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-phenylpyrimidine (B4PyPPM), to modify a perovskite film via an anti-solvent method is introduced. The nitrogen sites of pyrimidine and pyridine rings in B4PyPPM exhibit strong interactions with the undercoordinated lead ions in... 

This research explored the influences of shielding gases on the appearance of weld beads and the microstructures and mechanical properties of thin-wall samples using conventional gas metal arc welding as the heat source by using 5356 aluminium alloy welding wire as the raw materials and nitrogen (N2) and argon (Ar) as the shielding gases. The results showed that under the same parameters and after mono-layer single-bead welding was performed using N2 as the shielding gas, the bead height was higher, the bead width was narrower, and the penetration depth was shallower. The grain size of the thin-wall sample protected by N2 was 43.5–47.8 % smaller than that obtained under Ar protection.... 

In the current work, the role of Co and Ag co-doping on the electric, optical, and sensing performance of tin dioxide nano particles was investigated. Hydrothermally (co-)precipitation of the dopants was utilized to fabricate pure SnO2 and Sn0.96-xCo0.04AgxO2 (x = 0, 0.02, 0.04) nanoparticles. The crystal structure and microstructure of SnO2 particles was almost unchanged although Co-Ag co-doping reduced particle size from 51.8 nm to 41.6 nm and the unit cell dimensions changed. Overall, Co and Ag resulted in significant rise in oxygen vacancy of SnO2 so that defects compensate unbalanced electron charge induced by dopants. It was also figured out that Co-Ag co-doping improved the... 

We investigate the reconstruction of 3D human-object interactions from images, encompassing 3D human shape and pose estimation as well as object shape and pose estimation. To address this task, we introduce an autoregressive transformer-based variational autoencoder capable of learning a robust shape prior from extensive 3D shape datasets. Additionally, we leverage the reconstructed 3D human body as supplementary features for object shape and pose estimation. In contrast, prior methods only predict object pose and rely on shape templates for shape prediction. Experimental findings on the BEHAVE dataset underscore the effectiveness of our proposed approach, achieving a 40.7cm Chamfer distance... 

The adhesion and mechanical properties of hydrogels used for vascular wound repair often deteriorate dramatically on wet surfaces, resulting in ineffective repair. In this work, a poly(N-isopropyl acrylamide-co-dopamine methacrylamide) nanogel with dopamine groups was synthesized and introduced into a polyacrylamide (PAAm) hydrogel to produce temperature-responsive hydrogels, which greatly improved mechanical and adhesive properties of PAAm hydrogels. Nanogel-reinforced PAAm (NR-PAAm hydrogel) can adhere to the surface of various solid materials and biological tissues through special physical interactions, which exhibited different mechanical and adhesion properties as temperature changes... 

Experiments were conducted to investigate the effect of adding fines on the tribo-charging of coarse glass beads. Four types of fines, i.e., copper, stainless steel, uncoated and silver-coated fine glass beads, mixed with 240–830 μm glass beads were conveyed by air through a stainless-steel spiral pipe acting as a tribo-charger. Regardless of the type or electrical conductivity of the fine particles tested, adding small amounts of fines (up to 10 wt%) to coarse glass beads resulted in a sharp increase in the mass and surface charge densities of the particles. In general, the profiles of the mass and surface charge densities of the fine–coarse particle mixtures as a function of the mixture... 

Animal models and traditional cell cultures are essential tools for drug development. However, these platforms can show striking discrepancies in efficacy and side effects when compared to human trials. These differences can lengthen the drug development process and even lead to drug withdrawal from the market. The establishment of preclinical drug screening platforms that have higher relevancy to physiological conditions is desirable to facilitate drug development. Here, a heart-on-a-chip platform, incorporating microgrooves and electrical pulse stimulations to recapitulate the well-aligned structure and synchronous beating of cardiomyocytes (CMs) for drug screening, is reported. Each chip... 

Recently, an inequality satisfied by noncontextual hidden-variable models and violated by quantum mechanics for all states of a four-level system has been derived based on an information-theoretic distance approach to nonclassical correlations. In this Rapid Communication, we experimentally demonstrate the violation of this inequality with single photons. Our experiment offers a method to study a distinction between quantum and classical correlations from an information-theoretic perspective. © 2020 American Physical Society  

Urea is a major source of nitrogen pollution in domestic sewage and its denitrification is difficult since it is very likely to be converted into ammonia or nitrate instead of expected N2. Herein, we propose an exhaustive denitrification method for urea via the oxidation of amine/ammonia-N with chlorine oxide radical, which induced from a bi-functional RuO2//WO3 anode, and the highly selective reduction of nitrate-N on cathode in photoelectrochemical cell (PEC). Under illumination, the WO3 photoanode side promotes the quantities hydroxyl and reactive chlorine radical, and these radicals are immediately combined to stronger chlorine oxide radical by RuO2 side, which obviously enhances the... 

Microchannels in hydrogels play an essential role in enabling a smart contact lens. However, microchannels have rarely been created in commercial hydrogel contact lenses due to their sensitivity to conventional microfabrication techniques. Here, we report the fabrication of microchannels in poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels that are used in commercial contact lenses with a three-dimensional (3D) printed mold. We investigated the corresponding capillary flow behaviors in these microchannels. We observed different capillary flow regimes in these microchannels, depending on their hydration level. In particular, we found that a peristaltic pressure could reinstate flow in... 

The main motivation of this study is to address the challenges due to high penetration of renewable distributed energy resources (DERs) and efficiently benefit from DERs in distribution system planning (DSP). This paper considers a decentralized enhanced platform for DSP which is coordinated with bulk power system planning (PSP) to keep the optimality and security of the whole power system. In the proposed coordinated approach, distribution system operators (DSOs) plan and operate DERs to upgrade their local distribution areas (LDAs), supply forecasting local load growth, and avoid or defer costly generation and transmission expansion planning at the bulk power system. The proposed DSP model... 

A new magnetic quaternary photocatalyst, K4Nb6O17/α-Fe2O3/Fe3N/g-C3N4, was synthesized via a simple one-step thermal pyrolysis process. The prepared photocatalyst was well characterized, and its photocatalytic activity was evaluated towards acetamiprid pesticide degradation, CO2 reduction reaction, and U87-MG cell eradication. The coexistence of four different crystalline structures in the prepared photocatalyst could simultaneously facilitate photoelectron transport and suppress charge recombination through their coupled heterogeneous interfaces. Because of the coexistence of various photosensitive compounds, the prepared photocatalyst showed the excellent capability to harvest the visible... 

Copper phthalocyanine can effectively act as alternative small molecule hole transporting material in perovskite solar cells. In order to produce solution processed devices, a soluble copper phtalocyanine has been synthesized by n-butyl substitution and it was compared to commercially available tert-butyl substituted copper phthalocyanine. It was found that the configuration of the butyl chain plays a very important role in film conductivity and in the subsequent efficiency of solar cells, n-bytyl derivative being the most effective hole transporter. Such a result is due to the fact that n-butyl derivative allows better packing of the molecules in the film and stronger π-π interaction  

A pragmatic distributed algorithm (PDA) is proposed for supporting the ef-cient spectral access of multiple Primary Users (PUs) and Cognitive Users (CUs) in cooperative Cognitive Radio (CR) networks. The CUs may serve as relay nodes for relaying the signal received from the PUs to their destinations, while both the PUs' and the CUs' minimum rate requirements are satis-ed. The key idea of our PDA is that the PUs negotiate with the CUs concerning the speci-c amount of relaying and transmission time, whilst reducing the required transmission power or increasing the transmission rate of the PU. Our results show that the cooperative spectral access based on our PDA reaches an equilibrium, when it... 

To limit the peak power consumption of a cluster, a centralized power capping system typically assigns power caps to the individual servers, which are then enforced using local capping controllers. Consequently, the performance and throughput of the servers are affected, and the runtime of jobs is extended as a result. We observe that servers in big data processing clusters often execute big data applications that have different tolerance for approximate results. To mitigate the impact of power capping, we propose a new power-Capping aware resource manager for Approximate Big data processing (CAB) that takes into consideration the minimum Quality-of-Result (QoR) of the jobs. We use... 

At present, nanoparticles are used for various biomedical applications where they facilitate laboratory diagnostics and therapeutics. More specifically for drug delivery purposes, the use of nanoparticles is attracting increasing attention due to their unique capabilities and their negligible side effects not only in cancer therapy but also in the treatment of other ailments. Among all types of nanoparticles, biocompatible superparamagnetic iron oxide nanoparticles (SPIONs) with proper surface architecture and conjugated targeting ligands/proteins have attracted a great deal of attention for drug delivery applications. This review covers recent advances in the development of SPIONs together... 

Traditional fluorescence switching molecules achieving the state change between on and off states commonly based on UV irradiation. However, it is worth noting that UV irradiation is harmful to both the cancer cells and the normal cells. To achieve fluorescence switching under visible wavelength and avoid complicate molecular design, a fluorophore of 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene (4CzIPN) and a quencher of diarylethene (DAE) were physically incorporated within the biocompatible block copolymer poly(lactic-co-glycolic acid)-b-poly(ethylene glycol) (PLGA-b-PEG) to form 4CzIPN-DAE nanoparticles (NPs) through flash nanoprecipitation (FNP). By using the FNP method, the NPs... 

We propose and theoretically and experimentally demonstrate a novel tunable spurious-free single-loop optoelectronic oscillator (OEO) with low drift and low-phase noise. In the proposed transposed-frequency OEO (TF-OEO), a nonreciprocal bias unit and an optical phase modulator in a fiber Sagnac interferometer function jointly as an intrinsically drift-free intensity modulator, which improves the long-term drift. Besides, a transposed-frequency low-noise filtered amplifier is used which replaces the conventional radio frequency (RF) bandpass filter (BPF) and RF amplifier with an intermediate frequency (IF) BPF, an ultralow phase noise IF amplifier, and a tunable local oscillator, to attain...