Partitioning of MCHP‐TES system run time to incorporate transient system behaviour: a comprehensive exergy‐based analysis using simulation

By combining heat and power generation, mini‐combined and micro‐combined heat and power systems (MCHP) provide an efficient, decentralised means of power generation that can complement the composition of the electricity generation mix. Dynamic tools capable of handling transient system behaviour are required to assess MCHP efficiency beyond a mere static analysis based on steady‐state design parameters. Using a simulation of a cogeneration system, we combine exergetic definitions for different operational system states to quantify the overall system efficiency continuously over the whole period of operation. The concept of exergy allows direct comparison of different forms of energy. A sensitivity analysis was performed where we quantified the effect on MCHP overall performance under varying engine rotational speed, thermal energy storage size and fluid storage temperature in a range of MCHP simulations. We found that the exergetic quantity of natural gas used by the MCHP decreased slightly at higher engine speeds (?2% to ?4%). While the total amount of electricity generated is almost constant across the range of different engine output, more thermal exergy (up to +21%) can be recovered when the engine is operating at elevated speeds. Furthermore, selection of specific optimal thermal storage fluid temperatures can aid in improving system efficiency. Copyright © 2016 John Wiley & Sons, Ltd.     

Interference from retrieval cues in Parkinson's disease.

Objective: Existing studies on memory interference in Parkinson's disease (PD) patients have provided mixed results and it is unknown whether PD patients have problems in overcoming interference from retrieval cues. We investigated this issue by using a part-list cuing paradigm. In this paradigm, after the study of a list of items, the presentation of some of these items as retrieval cues hinders the recall of the remaining ones. Method: We tested PD patients' (n = 19) and control participants' (n = 16) episodic memory in the presence and absence of part-list cues, using initial-letter probes, and following either weak or strong serial associative encoding of list items. Results: Both PD patients and control participants showed a comparable and significant part-list cuing effect after weak associative encoding (13% vs. 12% decrease in retrieval in part-list cuing vs. no part-list cuing -control- conditions in PD patients and control participants, respectively), denoting a similar effect of cue-driven interference in the two populations when a serial retrieval strategy is hard to develop. However, only PD patients showed a significant part-list cuing effect after strong associative encoding (20% vs. 5% decrease in retrieval in patients and controls, respectively). Conclusions: When encoding promotes the development of an effective serial retrieval strategy, the presentation of part-list cues has a specifically disruptive effect in PD patients. This indicates problems in strategic retrieval, probably related to PD patients' increased tendency to rely on external cues. Findings in control conditions suggest that less effective encoding may have contributed to PD patients' memory performance. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Controlled Folding of 2D Au–Polymer Brush Composites into 3D Microstructures

Microscale, quasi‐2D Au–polymer brush composite objects are fabricated by a versatile, controllable process based on microcontact printing followed by brush growth and etching of the substrate. These objects fold into 3D microstructures in response to a stimulus: crosslinked poly(glycidyl methacrylate) (PGMA) brushes fold on immersion in MeOH, and poly(methacryloxyethyl trimethylammonium chloride) (PMETAC) brushes fold on addition of salt. Microcages and microcontainers are fabricated. A multistep microcontact printing process is also used to create sheets of Au–PGMA bilayer lines linked by a PGMA film, which fold into cylindrical tubes. The bending of these objects can be predicted, and hence predefined during the synthesis process by controlling the parameters of the gold layer, and of the polymer brush.     

Influence of the turning process on the distortion of disks for gear manufacture

This study presents investigations on the fundamental mechanisms of part distortion during the machining of disks (cylindrical gear base bodies). The work focuses on the effects of machining induced residual stresses and inhomogeneous material removal. In this context the workpiece clamping was investigated as a major impact factor on the distortion. In order to analyze and describe the complex shape deviations, an appropriate distortion characterization method was developed. Since the distortion of disks directly affects the gear wheel quality, the results will help to understand the formation of gear distortion as well as to reduce and compensate it.     

Enhanced Electron Mobility Due to Dopant‐Defect Pairing in Conductive ZnMgO

The increase of the band gap in Zn_1‐xMg_xO alloys with added Mg facilitates tunable control of the conduction band alignment and the Fermi‐level position in oxide‐heterostructures. However, the maximal conductivity achievable by doping decreases considerably at higher Mg compositions, which limits practical application as a wide‐gap transparent conductive oxide. In this work, first‐principles calculations and material synthesis and characterization are combined to show that the leading cause of the conductivity decrease is the increased formation of acceptor‐like compensating intrinsic defects, such as zinc vacancies (V_Zn), which reduce the free electron concentration and decrease the mobility through ionized impurity scattering. Following the expectation that non‐equilibrium deposition techniques should create a more random distribution of oppositely charged dopants and defects compared to the thermodynamic limit, the paring between dopant Ga_Zn and intrinsic defects V_Zn is studied as a means to reduce the ionized impurity scattering. Indeed, the post‐deposition annealing of Ga‐doped Zn_0.7Mg_0.3O films grown by pulsed laser deposition increases the mobility by 50% resulting in a conductivity as high as σ = 475 S cm^‐1.     

A multidimensional wave digital filter bank for video-based motion analysis

Multidimensional wave digital filters (MDWDF) exhibit the same desirable properties as 1D WDFs, most notably including passivity and therefore guaranteed stability as well as high robustness. A possible application for such MDWDFs may be found in motion analysis of image sequences by means of filters with fan-shaped transfer functions, where content with specific movement information can be extracted. For that matter, a parallel filter bank is needed to differentiate object motion into separate classes. In this paper, a new specialized MDWDF fan filter structure is introduced, possessing both reduced computational complexity and memory requirements compared to existing approaches. Additionally, part of the processing can be shared among all bands, further increasing efficiency.     

Monetite and brushite coated magnesium: in vivo and in vitro models for degradation analysis

The use of magnesium (Mg) as a biodegradable metallic replacement of permanent orthopaedic materials is a current topic of interest and investigation. The appropriate biocompatibility, elastic modulus and mechanical properties of Mg recommend its suitability for bone fracture fixation. However, the degradation rates of Mg can be rapid and unpredictable resulting in mass hydrogen production and potential loss of mechanical integrity. Thus the application of calcium phosphate coatings has been considered as a means of improving the degradation properties of Mg. Brushite and monetite are utilized and their degradation properties (alongside uncoated Mg controls) are assessed in an in vivo subcutaneous environment and the findings compared to their in vitro degradation behaviour in immersion tests. The current findings suggest monetite coatings have significant degradation protective effects compared to brushite coatings in vivo. Furthermore, it is postulated that an in vitro immersion test may be used as a tentative predictor of in vivo subcutaneous degradation behavior of calcium phosphate coated and uncoated Mg.