Carbon-Methanol Based Adsorption Heat Pumps: Identifying Accessible Parameter Space with Carbide-Derived Carbon Model Materials

In adsorption heat pumps, the properties of the porous adsorbent and the refrigerant determine the performance. Major parameters for this working pair are the total uptake of the adsorptive, its kinetics, and the heat transfer characteristics. In the technical application despite powdered adsorbents, thin consolidated layers of the adsorbent can be attractive and obtained by a binder-based approach but likely result in competing material properties. Thus, for a process optimization, the accessible parameter space and interdependencies have to be known and were deduced in this work for model porous carbons (carbide-derived carbons derived from TiC and ZrC) and methanol as well as the addition of different amounts of boron nitride, silver, and graphite as heat-conductive agents and the use of two binders.     

Monetary‐based availability: A novel approach to assess the performance of wind turbines

With the background of numerous wind turbines phasing out of fixed feed‐in tariffs in the following years and an increasing share of negative electricity market prices on the spot market, the availability definitions of “time‐based” and “production‐based” availability are possibly no longer suitable for assessing the overall performance of a wind turbine. This paper introduces a novel definition: the “monetary‐based” availability. The differences between the established definitions and the “monetary‐based” availability are highlighted by comparing the measures on an empirical data set. Furthermore, results on the impact of scheduling planned downtimes towards a monetary‐based optimum show that revenues can be increased. By shifting only a small share of the annual downtime to an optimum to maximize the revenue from electricity, a strong increase in additional earnings and thereby an increasment of the monetary‐based availability can be achieved.     

Joint academic and industrial efforts towards innovative and efficient solutions for clinical needs

The 4^th Translational Research Symposium (TRS) was organised at the annual meeting of the European Society for Biomaterials (ESB) 2017, Athens, Greece, with a focus on ‘Academia—Industry Clusters of Research for Innovation Catalysis’. Collaborations between research institutes and industry can be sustained in several ways such as: European Union (EU) funded consortiums; syndicates of academic institutes, clinicians and industries; funding from national governments; and private collaborations between universities and companies. Invited speakers from industry and research institutions presented examples of these collaborations in the translation of research ideas or concepts into marketable products. The aim of the present article is to summarize the key messages conveyed during these lectures. In particular, emphasis is put on the challenges to appropriately identify and select unmet clinical needs and their translation by ultimately implementing innovative and efficient solutions achieved through joint academic and industrial efforts.     

Discrete adjoint gradient evaluations for linear stress and vibration analysis

This paper presents methods used to perform discrete adjoint gradient evaluations for linear stress and vibration analysis. The methods are implemented within the framework of a discrete adjoint structural solver being developed for multidisciplinary adjoint optimizations of turbomachinery components. The code is differentiated using the algorithmic differentiation tool CoDiPack in tandem with manual treatment of the iterative solvers. Stress analysis leads to a linear system of equations that is typically solved by an iterative solver (e.g. GMRES). To ensure accuracy, the adjoint problem is formulated as a new linear system of equations to be solved. Vibration analysis results in a generalized eigenvalue problem that is also typically solved by an interative solver. The adjoint problem takes out the generalized eigenvalue solve and replaces it by one outer product per eigenfrequency, leading to significantly cheap eigenfrequency gradients for vibration analysis.

     

Strain-Induced Dissolution of Cementite in Cold-Drawn Pearlitic Steel Wires

Metallurgical and Materials Transactions A - Strain-induced dissolution of cementite is one of the most important microstructural changes undergone by a pearlitic steel wire during cold drawing,...     

Limits of High Recovery Inland Desalination: Closed-Circuit Reverse Osmosis – a Viable Option?

Cost-efficient operation of inland brackish water reverse osmosis (BWRO) demands a high recovery. As recovery of BWRO is often limited to scaling, antiscalants (AS) are applied, whose environmental impact is disputed. In this paper, different systems (conventional single- and two-stage plug flow RO (PFRO) and closed-circuit RO (CCRO)) were simulated in various configurations (AS dosing, ion exchange (IEX) pretreatment, elements per vessel) to determine the recovery limiting factor for a hard feed. The novel proposed IEX-CCRO reached the highest recovery without AS dosing. PFRO configurations had lower recoveries, mainly due to hydraulic limitations. Utilizing RO brine reduced both the water demand and salts necessary for IEX regeneration.     

Investigation of microstructure-property relantionships of magnesia-hercynite refractory composites by a refined digital image correlation technique

Industrial magnesia-spinel bricks destined for thermal shock applications often show more flexibility and improved crack growth resistance. Components from the spinel structure group are usually added to promote microcracking coming from thermal expansion mismatch. This leads to the development of toughening mechanisms that are very effective in improving the crack propagation resistance.Magnesia-hercynite composites were investigated in order to highlight their fracture process, with regard to their microstructure, by using Digital Image Correlation (DIC). The direct measurement of displacement fields between digital images of the reference state and the deformed one has provided valuable information on material deformation during loading. The aim of this work was to investigate the fracture behaviour of refractories through the coupling of the Wedge Splitting Test (WST) and DIC. By using a refined DIC process transformation taking into account a discontinuity of displacement, called 2P-DIC, a more effective characterisation of the fracture behaviour was achieved.     

A new approach to nonlinear optimal feedback law

For a fixed-time free endpoint optimal control problem it is shown that the optimal feedback control satisfies a system of ordinary differential equations. They are obtained using an elimination procedure of the adjoint vector which appears linearly in a set of differential equations. These equations, involving Lie brackets of vector fields, are derived from the Maximum Principle. An application of this approach to robotics is given.     

Technology report: Work product retrieval systems in today's law offices

Contemporary law offices use many different technologies for storing and retrieving documents produced in the course of legal work. This article examines two approaches in detail: document management, as exemplified by SoftSolutions, and electronic publishing, as exemplified by Folio VIEWS. Some other approaches are reviewed, and the pragmatics, politics, economics, and legalities of legal work product retrieval are discussed.