Comparison of direct electrocaloric characterization methods exemplified by 0.92 Pb(Mg1/3Nb2/3)O3‐0.08 PbTiO3 multilayer ceramics

Electrocaloric device structures have been developed as multilayer ceramics (MLCs) based on fundamental research carried out on PMN‐8PT bulk ceramics. Two different MLC structures were prepared with nine layers each and layer thicknesses of 86 μm and 39 μm. The influence of the device design on its properties has been characterized by microstructural, dielectric, ferroelectric, and direct electrocaloric measurement. For direct characterization two different methods, ie temperature reading (thermistor and thermocouple) and heat flow measurement (differential scanning calorimetry), were used. A comparison of results revealed a highly satisfactory agreement between the different methods. This study confirms that MLCs are promising candidates for implementation into energy‐efficient electrocaloric cooling systems providing large refrigerant volume and high electrocaloric effect. Due to their micron‐sized active layers, they allow for the application of high electric fields under low operation voltages. We measured a maximum electrocaloric temperature change of ΔT=2.67 K under application/withdrawal of an electric field of ΔE=16 kV mm^?1, which corresponds to operation voltages below 1.5 kV.     

Studies on the thermal stability of poly/vinyl chloride/ and vinyl chloride - carbon monoxide copolymers

Thermal stability of vinyl chloride/carbon monoxide copolymers synthetized in the presence of different proportions of carbon monoxide was studied in nitrogen, oxygen or air stream at 180°C. Dehydrochlorination rate increases proportionally to the incorporated carbonyl content. Effect of air and oxygen on acceleration of the decomposition is higher for PVC samples of regular structure than for the vinyl chloride/carbon monoxide copolymers. In the infra-red spectra recorded after the thermal oxidative decomposition, a broad absorption band appears between 1600 and 1800 cm^?1. Two peaks show the most emphasized increase: one at 1720 to 1730 cm^?1 assigned to the carbonyl group and another at about 1770 cm^?1 of unidentified origin. Additional oxidation products from the polyene yield a “shoulder” in the spectrum between 1600 and 1690 cm^?1.     

Switching on the photochemical reactivity in heterodimetallic Os–Ru bipyridyl complexes containing a bis(bidentate) phosphine

For the first time the excited states of the RuP₂N₄ moiety belonging to a new heterodimetallic Os^II–Ru^II bipyridyl complex are successfully designed in order to introduce photochemical reactivity. This dramatic effect is achieved via the use of the sterically demanding bis(bidentate) phosphine cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb). Thus, the temperature dependence of the luminescence lifetimes ranging from 77 to 298 K for the novel homodimetallic species meso-(ΔΛ/ΛΔ)-[Os₂(dppcb)(bpy)₄](PF₆)₄ (1) and rac-(ΔΔ/ΛΛ)-[Os₂(dppcb)(bpy)₄](PF₆)₄ (2) clearly indicates that the d–d state responsible for photochemistry is not populated. By contrast, the analogous temperature dependence for the new heterodimetallic species ΔΛ/ΛΔ-[Os(bpy)₂(dppcb)Ru(bpy)₂](PF₆)₄ (3) and ΔΔ/ΛΛ-[Os(bpy)₂(dppcb)Ru(bpy)₂](PF₆)₄ (4) unequivocally shows that as a consequence of the population of the d–d state the photochemical reactivity is switched on. Since single crystal X-ray structure analyses are a major clue to the understanding of photophysical and photochemical properties, also the X-ray structures of 1–3 are given.     

Allocation Information and Operational Strategies

Abstract

This paper investigates firms' management of reported allocated overhead information and the relationship between operational strategies and overhead costs allocation. Using data from California hospitals for the years 1981–1991, I find that hospitals reallocate more overhead costs to cost-based services when they are subject to a dual payment system featuring both cost-based and fixed-rate payers. This management of reported overhead cost information does not involve a change in real expenses. Furthermore, the evidence also shows that under a dual payment system, hospitals adopt cost-increasing operational strategies, which increase direct costs of cost-based services and then reallocate costs when they have sufficient bargaining power to charge higher prices for their services. When hospitals are not able to negotiate a high price, they control costs while continuing to reallocate overhead costs among services.     

Delay-sensitive approaches for anonymizing numerical streaming data

Streaming data are widely used in today’s world. Data come from different sources in streams and must be processed online and with minimum delay. These data stream can contain confidential data such as customers’ purchase information and need to be mined in order to reveal other useful information like customers’ purchase patterns. Privacy preservation throughout these processes plays a crucial role. K-anonymity is a well-known technique for preserving privacy. The principle issues in k-anonymity are information loss and running time. Although some of the existing k-anonymity techniques are able to generate anonymized data with acceptable information loss, their main drawback is that they are very time-consuming and are not applicable in a streaming context since streaming data are usually very sensitive to delay and need to be processed quite fast. In [32], we proposed a cluster-based k-anonymity algorithm called fast anonymizing algorithm for numerical streaming data (FAANST) which can anonymize numerical streaming data quite fast while providing an admissible information loss. The main drawback of FAANST is that some tuples may remain in the system for a long time and are output when they might be considered to have expired. In this paper, we propose two extensions for FAANST, passive and proactive solutions. These two solutions put a soft deadline, called $delay$ , on the time each tuple can stay in the system, and if a tuple passes this deadline, these algorithms force the tuple to be output. The proactive solution goes even one step further and utilizes a simple heuristic function to predict when a tuple in the system may expire and outputs the tuple if it will expire in the next round of the algorithm’s execution.     

Computing confidence intervals for point process models

Characterizing neural spiking activity as a function of intrinsic and extrinsic factors is important in neuroscience. Point process models are valuable for capturing such information; however, the process of fully applying these models is not always obvious. A complete model application has four broad steps: specification of the model, estimation of model parameters given observed data, verification of the model using goodness of fit, and characterization of the model using confidence bounds. Of these steps, only the first three have been applied widely in the literature, suggesting the need to dedicate a discussion to how the time-rescaling theorem, in combination with parametric bootstrap sampling, can be generally used to compute confidence bounds of point process models. In our first example, we use a generalized linear model of spiking propensity to demonstrate that confidence bounds derived from bootstrap simulations are consistent with those computed from closed-form analytic solutions. In our second example, we consider an adaptive point process model of hippocampal place field plasticity for which no analytical confidence bounds can be derived. We demonstrate how to simulate bootstrap samples from adaptive point process models, how to use these samples to generate confidence bounds, and how to statistically test the hypothesis that neural representations at two time points are significantly different. These examples have been designed as useful guides for performing scientific inference based on point process models.     

Personality factors related to shift work tolerance in two- and three-shift workers

This study aimed to investigate whether different personality variables were associated with shift work tolerance, and whether these potential associations were moderated by various types of shift work. The sample comprised 1505 nurses who worked either two or three rotating shifts. Personality traits were measured in terms of morningness, flexibility, languidity and hardiness. Morningness reflects the tendency to be alert relatively early in the morning and sleepy relatively early in the evening. Flexibility denotes the ability to both work and sleep at odd times of the day, while languidity concerns the tendency to become tired/sleepy when cutting down on sleep. Hardiness relates to resilience to stressful life events. The dependent variables in this study comprised of measures of insomnia, sleepiness, depression and anxiety. Hierarchical regression analyses, which controlled for demographic variables and work load, revealed that Morningness was significantly and negatively related to insomnia. The Morningness by Shift type interaction was overall significant for depressive symptoms. Morningness was near significantly associated with lower levels of depressive symptoms in three-shift workers, but unrelated to depressive symptoms in two-shift workers. Flexibility was associated with higher levels of depressive symptoms. Flexibility by Shift type interaction was significant for insomnia, indicating that flexibility was negatively associated with insomnia for three-shift workers and unrelated with insomnia for two-shift workers. Languidity was associated with higher levels of sleepiness, depressive and anxiety symptoms. Hardiness was associated with lower levels of all four dependent variables.     

Nanocomposites for electronic applications that can be embedded for textiles and wearables

In the present review, we have selected advances in electrospinning nanofibers that we envision to be embedded in textiles and wearables. These nanofibers have been proven to be excellent options for applications such as power generation, sensing, and communication. Their similitude with already known woven meshes makes these fibers perfect for electronically active textiles.These fibers offer well known characteristics such as mechanical flexibility, high surface area-to-volume ratio, light weight and can be tuned by carefully selecting the active materials in the precursor solution. Here we will discuss polymers with electroactive, piezoelectric, triboelectric and their composites that have been used in fiber structures by using the electrospinning technique.     

Introducing the qualitative performance gap: stories about a sustainable building

ABSTRACT

In the design and operations industries, the performance gap is a common discrepancy found between predicted building energy performance and actual energy performance. The performance gap is considered to have negative impacts for the brand of ‘green’ buildings, designers and operators. A socially based analogue is proposed here: the qualitative performance gap, defined as the perceived gap between what inhabitants expect and their actual experience of the building environment. This concept is explored at a regenerative Living Lab: the Centre for Interactive Research on Sustainability (CIRS) in Vancouver, Canada. ‘Official’ and ‘lived’ stories about the building were interpreted from sources of building information and interviews. Expectations about and forgiveness of building performance were gained from pre- and post-occupancy evaluations and interviews. The solution to the qualitative performance gap is not to eliminate it, but, in line with the concept of interactive adaptivity, to use the gap to generate new stories and new consequences for human wellbeing. The qualitative performance gap is thus conceived as positively generative, of new stories of place and identity. This work recommends crafting an ‘official story’ of social aspirations, and a communication feedback loop amongst designers, operators and building inhabitants, transparently sharing successes and failures.     

Fabrication of particle and composition gradients by systematic interaction of sedimentation and electrical field in electrophoretic deposition

The systematic interaction of sedimentation and electrical field in electrophoretic deposition allows the tailoring of specific properties of deposited green bodies. This technique permits a selective deposition of the nanosized fraction of conventional powders with broad or non-monomodal particle size distribution, thus making preceding classification obsolete. Potential applications are coatings with a very smooth surface or the replication of microstructures or moulds which are filled with nanosized particles and subsequently with coarser particles as support in one process step. Also, graded structures can be fabricated with regard to particle size distribution, porosity and composition (e.g. zirconia toughened alumina). In this paper, the interaction of sedimentation and electrical field in electrophoretic deposition is described. In addition the effectiveness of the combined process will be shown.