Low-loss 25.3km few-mode ring-core fibre for mode-division multiplexed transmission

We report the design, fabrication and characterisation of a few-mode ring-core fibre supporting 4 mode groups. The low loss (~0.3dB/km) and length (25.3km) are both records for a ring-core fibre

Alite calcium sulfoaluminate cement: chemistry and thermodynamics

Calcium sulfoaluminate (C$A) cement is a binder of increasing interest to the cement industry and is undergoing rapid development. Current formulations do not contain alite; however, alite calcium sulfoaluminate (a-C$A) cements can combine the favourable characteristics of Portland cement (PC) with those of C$A cement while also having a lower carbon dioxide footprint than the current generation of PC clinkers. This paper presents two results on the formation of a-C$A clinkers. The first is a thermodynamic study demonstrating that the production of a-C$A clinker is possible without the use of mineralisers, doping with foreign elements, or using multiple stages of heating. It is established that a-C$A clinker can be readily produced in a standard process by controlling the oxygen and sulfur dioxide fugacity in the atmosphere. This allows for the stabilisation of ye’elimite to the higher temperatures required for alite stability. The second result establishes that when using fluorine to mineralise a-C$A clinker production, the iron content in the clinker is also an important variable. Although the exact mechanism of alite stabilisation is not known, it is shown that alite formation increases with the combination of calcium fluoride and iron (III) oxide in the mix

CFD investigation of gas-solids flow in a new fluidized catalyst cooler

In our previous work, a new concept of annular catalyst cooler (ACC) was proposed and validated experimentally, which showed that an internal circulation of solids could be formed by using two gas distributors and both hydrodynamics and heat transfer could be largely improved. The current work simulated detailed hydrodynamics of gas-solids flow to advance our understanding of the ACC by using the two-fluid model. The influences of effective particle diameter dp⁎ and specularity coefficient φ were examined and compared with experimental data. Optimum values of dp⁎ = 170 μm and φ = 0.3 were determined and used in the simulations. Detailed hydrodynamics of gas-solids flow were then obtained, and the influential parameters were examined. The results showed that the proper selection of the ratio of gas velocities and the position of the heat transfer tube were needed to form a stable internal solids circulation in the ACC. The ACC had a combined hydrodynamic feature of up-flow and down-flow catalyst coolers with bigger solids volume fraction and smaller particle resident time, which are beneficial for improving the heat transfer between solids and wall

The benefit of sequentiality in social networks *

Abstract This paper examines the benefit of sequentiality in the social networks. We adopt the elegant theoretical framework proposed by We then examine the structure of optimal mechanism and allow for arbitrary sequence of players' moves. We show that starting from any fixed sequence, the aggregate contribution always goes up while making simultaneous-moving players move sequentially. This suggests a robust rule of thumbs -any local modification towards the sequential-move game is beneficial. Pushing this idea to the extreme, the optimal sequence turns out to be a chain structure, i.e., players should move one by one. Our results continue to hold when either players exhibit strategic substitutes instead or the network designer's goal is to maximize the players' aggregate payoff rather than the aggregate contribution

Dystroglycan versatility in cell adhesion: a tale of multiple motifs

Dystroglycan is a ubiquitously expressed heterodimeric adhesion receptor. The extracellular a-subunit makes connections with a number of laminin G domain ligands including laminins, agrin and perlecan in the extracellular matrix and the transmembrane b-subunit makes connections to the actin filament network via cytoskeletal linkers including dystrophin, utrophin, ezrin and plectin, depending on context. Originally discovered as part of the dystrophin glycoprotein complex of skeletal muscle, dystroglycan is an important adhesion molecule and signalling scaffold in a multitude of cell types and tissues and is involved in several diseases. Dystroglycan has emerged as a multifunctional adhesion platform with many interacting partners associating with its short unstructured cytoplasmic domain. Two particular hotspots are the cytoplasmic juxtamembrane region and at the very carboxy terminus of dystroglycan. Regions which between them have several overlapping functions: in the juxtamembrane region; a nuclear localisation signal, ezrin/radixin/moesin protein, rapsyn and ERK MAP Kinase binding function, and at the C terminus a regulatory tyrosine governing WW, SH2 and SH3 domain interactions. We will discuss the binding partners for these motifs and how their interactions and regulation can modulate the involvement of dystroglycan in a range of different adhesion structures and functions depending on context. Thus dystroglycan presents as a multifunctional scaffold involved in adhesion and adhesion-mediated signalling with its functions under exquisite spatiotemporal regulation

Performance Study of a Leaf-Vein-like Structured Vapor Chamber

As optoelectronic products continue to advance rapidly, the need for effective heat dissipation has become increasingly crucial due to the emphasis on miniaturization and high integration. The vapor chamber is widely used for cooling electronic systems as a passive liquid–gas two-phase high-efficiency heat exchange device. In this paper, we designed and manufactured a new kind of vapor chamber using cotton yarn as the wick material, combined with a fractal pattern layout of leaf veins. A comprehensive investigation was conducted to analyze the performance of the vapor chamber under natural convection circumstances. SEM showed that many tiny pores and capillaries were formed between the cotton yarn fibers, which are very suitable as the wick material of the vapor chamber. Additionally, experimental findings demonstrated the favorable flow and heat transfer characteristics of the cotton yarn wick within the vapor chamber, which makes the vapor chamber have significant heat dissipation capability, compared to the other two vapor chambers; this vapor chamber has a thermal resistance of only 0.43 °C/W at a thermal load of 8.7 W. In addition, the vapor chamber showed good antigravity capability, and its performance did not show significant changes between horizontal and vertical positions; the maximum difference in thermal resistance at four tilt angles is only 0.06 °C/W. This paper also studied the influence of vacuum degree and filling amount on the performance of the vapor chamber. These findings indicate that the proposed vapor chamber provides a promising thermal management solution for some mobile electronic devices and provides a new idea for selecting wick materials for vapor chambers

Fabrication of Cu-adhered silicon carbide particles and its effect on properties of Fe-based matrix composites

In present study, copper powders (Cu) and silicon carbide (SiC) particles were used to produce Cu-adhered SiC particles (Cu/SiC), which were used to reinforce Fe-based matrix materials to modify properties. The orthogonal experimental design was used to investigate the relationship between ball mill parameters and particle size. Next, the mixed powders were pressed at 500 MPa using a hydraulic press. Then, the green compacts were wrapped in graphite powders, and sintered using a resistance furnace. Metallurgical microscopy, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffraction were employed to investigate the microstructures, element distribution, and phase of SiC-reinforced Fe-based matrix composites. The properties of the SiC-reinforced metal matrix composites were determined using the Microhardness test and Charpy pendulum impact test. The orthogonal experimental results indicated that the influence degree of milling parameters on particle size was the powder to ball ratio>milling time>milling speed. The milling parameters to obtain the smallest Cu/SiC particle were powder to ball ratio of 20:1, milling time of 15 h, and milling speed of 300 r min ^−1 . However, the adhesive effect was bad. The properties test results indicated that Cu/SiC particles reinforced with Fe matrix composites had better properties. Furthermore, the hardness and impact toughness improved up to 239.97 HV0.5 and 12.1 KJ·m ^−2 , respectively. Moreover, compared to raw SiC particles, the hardness and impact toughness increased by 12% and 15%, respectively. The improvement in properties was attributed to the Cu adhesion to the SiC surface, which effectively alleviated the difference in thermal expansion coefficient between SiC and Fe, and formed a chemical bond at the interface to improve the interfacial bindin