ELID grinding of silicon wafers: A literature review

Silicon wafers are the most widely used substrates for fabricating integrated circuits. There have been continuous demands for higher quality silicon wafers with lower prices, and it becomes more and more difficult to meet these demands using current manufacturing processes. In recent years, research has been done on electrolytic in-process dressing (ELID) grinding of silicon wafers to explore its potential to become a viable manufacturing process. This paper reviews the literature on ELID grinding, covering its set-ups, wheel dressing mechanism, and experimental results. It also discusses the technical barriers that have to be overcome before ELID grinding can be used in manufacturing.     

Design of laminate composite layups using genetic algorithms

Fibre-reinforced laminate composites have attractively high stiffnesses and strengths and low densities. However, designing with laminate composites is more difficult than designing with metals because (a) it involves the design of the material itself, and its manufacturing route, at the same time, (b) laminates are highly anisotropic, and (c) they have complex failure modes. The failure modes and anisotropy combine to make design details unintuitively important and small detailed-design oversights have been responsible for most failures in composite structures. Design is the process of converting an idea into information from which a product can be made. Thus the central role of information processing in any design activity implies that software should be able to help. Here we show three different ways in which laminate stacking sequences can be designed.     

The amplitude dependence of the velocity of nonlinear second sound in helium II nearT λ

The amplitude dependence of the velocity of nonlinear second sound in Helium II, as given by the Khalatnikov nonlinear coefficient, was measured nearT using a single-pulse travel-time technique. Using nonplanar pulses which were amplified and focused by a spherical reflector, the confirmation of Khalanikov's second order two fluid model prediction was extended to within 7 mK of T much closer to the critical temperature than previously reported. This study was restricted to single pulses of second sound in order to ensure that the measurement pertained only to an undisturbed, vortextangle-free sample of Helium II.     

Ambient temperature CO oxidation using copper manganese oxide catalysts prepared by coprecipitation: effect of ageing on catalyst performance

Copper manganese oxides are prepared using a coprecipitation procedure and studied for the oxidation of CO at ambient temperature. In particular, the effect of the ageing tune, i.e. the time that the precipitate remains in contact with the precipitating medium, is investigated. It is shown that this parameter is of crucial importance in controlling the catalytic performance and that catalysts which are aged for 30 min or 300 min give the best performance. Preliminary characterisation using powder X-ray diffraction indicates that a combination between CuO and copper manganese oxide may be responsible for the enhanced activity observed with these samples.     

Inter-Flake Quantum Transport of Electrons and Holes in Inkjet-Printed Graphene Devices

2D materials have unique structural and electronic properties with potential for transformative device applications. However, such devices are usually bespoke structures made by sequential deposition of exfoliated 2D layers. There is a need for scalable manufacturing techniques capable of producing high-quality large-area devices comprising multiple 2D materials. Additive manufacturing with inks containing 2D material flakes is a promising solution. Inkjet-printed devices incorporating 2D materials have been demonstrated, however there is a need for greater understanding of quantum transport phenomena as well as their structural properties. Experimental and theoretical studies of inkjet-printed graphene structures are presented. Detailed electrical and structural characterization is reported and explained by comparison with transport modeling that include inter-flake quantum tunneling transport and percolation dynamics. The results reveal that the electrical properties are strongly influenced by the flakes packing fraction and by complex meandering electron trajectories, which traverse several printed layers. Controlling these trajectories is essential for printing high-quality devices that exploit the properties of 2D materials. Inkjet-printed graphene is used to make a field effect transistor and Ohmic contacts on an InSe phototransistor. This is the first time that inkjet-printed graphene has successfully replaced single layer graphene as a contact material for 2D metal chalcogenides.     

Employing the Dynamics of the Electrochemical Interface in Aqueous Zinc-Ion Battery Cathodes

Intrinsically stable materials are desirable for constructing energy storage devices, which aim to demonstrate durability under the harsh electrochemical conditions that are detrimental to their lifespan. However, it is demonstrated here that the intrinsic instability of an electrochemical interface can be converted from an obstacle into an advantage. In aqueous zinc-ion batteries, manganese oxide (MnO₂) exhibits considerable dissolution even in electrolyte containing Mn²⁺ salt. Balancing with redeposition alleviates the harmful impact of dissolution on performance and alters the trajectory of the active phase. Inclusion of Mn²⁺ salt in the electrolyte induces MnO₂ deposition on all conductive surfaces, requiring that distracting side reactions be eliminated to isolate the dynamics of the active phase. Under conditions favoring dissolution, capacity decreases dramatically and a highly crystalline tetragonal ZnMn₂O₄ phase forms, while redeposition helps maintain capacity and promotes a disordered cubic Zn-rich phase. Ultimately, this work aims to illuminate a path forward to unlock the potential of batteries made with materials that are fundamentally unstable in their operating environment.     

3D‐Printable Photochromic Molecular Materials for Reversible Information Storage

The formulation of advanced molecular materials with bespoke polymeric ionic‐liquid matrices that stabilize and solubilize hybrid organic–inorganic polyoxometalates and allow their processing by additive manufacturing, is effectively demonstrated. The unique photo and redox properties of nanostructured polyoxometalates are translated across the scales (from molecular design to functional materials) to yield macroscopic functional devices with reversible photochromism. These properties open a range of potential applications including reversible information storage based on controlled topological and temporal reduction/oxidation of pre‐formed printed devices. This approach pushes the boundaries of 3D printing to the molecular limits, allowing the freedom of design enabled by 3D printing to be coupled with the molecular tuneability of polymerizable ionic liquids and the photoactivity and orbital engineering possible with hybrid polyoxometalates.     

A cost‐effective sparse communication strategy for networked linear control systems: an SVD‐based approach

In networked control, there is often an incentive to communicate only what is absolutely necessary to achieve the desired performance goals. This is true to both the downlink (between a control base station and actuators) and the uplink (between the sensors and base station). Here, we present a strategy aimed at this problem based on a singular value decomposition of the Hessian of the quadratic performance index generally considered in Model Predictive Control. The singular vectors are employed to generate an orthonormal basis function expansion of the unconstrained solution to the finite horizon optimal control problem. These are preloaded into each actuator and each sensor. On the downlink, the actuators are informed, in real‐time, about which basis functions they should use. On the uplink, after a ‘burn in period’, the sensors need only communicate when their response departs from that pre‐calculated for the given basis functions. We show that this strategy facilitates communication in both the downlink and uplink in a cost‐effective fashion. We also show that the strategy can be modified so that input constraints are satisfied. We illustrate the proposed results by applying them to a simulation of the cross direction control of a paper machine. Potential extensions and other applications of the proposed strategy are also discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

The nutritional role of free sialic acid,a human milk monosaccharide,and its application as a functional food ingredient

N-Acetyl-d-neuraminic acid (NANA), more commonly known by its trivial name sialic acid, is an endogenous human and ubiquitous nutritional monosaccharide. As a bound sugar at the terminal positions of glycans NANA is known to play important roles in many biological events. The data that exist on the occurrence of the free monosaccharide in breast milk and nutrition, however, are less commonly discussed. In most foods of animal origin, sialic acid occurs as a mixture of NANA and N-glycolyl-d-neuraminic acid (NGNA), a hydroxylated derivative of NANA that is not found in humans. The dietary intake of NGNA has been identified as a risk factor for long-term adverse health effects. Therefore, we present summaries on the biochemistry, metabolism, bioavailability, and the data on NANA and NGNA levels that occur in diverse foods. Finally, we discuss the emerging data demonstrating that free NANA is linked to positive nutritional effects including pronounced antioxidative properties. These data and the extremely high safety profile of NANA justify dietary enrichment at levels that correspond to the dietary intake of NANA in infants through breast milk.