Field Performance Of Domestic Heat Pumps For Heating And Hot Water In Switzerland Part I: Technology, Methods And State Of The Art Of The Field Studies

carried out by the Heat Pump Test Center (WPZ) in Buchs SG, Switzerland. In the current study, heat pumps for hydronic heating systems in single family houses within Switzerland have been investigated since 2016. So far, over 20 air-source and geothermal heat pumps have been added to this governmental quality assurance program (Swiss Federal authority EnergieSchweiz). For each heat pump system, more than 40 measured variables are recorded at a time interval of 10 s with calibrated sensors with very low measurement uncertainty. The aim of this field study is to record the real heat pump system efficiency in operation and to draw comparisons with characteristic values from laboratory measurements and manufacturer data. The study presented, is divided into two parts. The first part that is entitled “Technology, Methods and State of the Art of the field studies” focuses on the procedure, system boundaries and measuring technology of past and current field studies at WPZ Buchs and provides an insight to the state of the art of field performance measurements of domestic heat pumps carried out in Switzerland. The second part is entitled “Results, Analysis and Optimization of current field studies” and concentrates on various measured figures and the improvement potential of the investigated heat pump systems. Compared to the former studies made in the 1990s and early 2000s, the measurement methodology and data acquisition have changed considerably to date. Nowadays, thanks to digitalization, much more data is available. Short sampling intervals are used to describe temporal processes in heat pump systems in detail, enabling an easier detection of defects such as heat losses and unwanted circulation. Thanks to carefully defined system boundaries like JAZ, WNG and SNG heat pump systems can be compared and optimized effectively. Great importance is attached to the measurement of temperature because of its major influence on the overall uncertainty. Therefore, temperature is measured with an uncertainty of ±0.1 K/±0.02 K (absolute/relative) using directly immersed PT-100 sensors and four wire technology. Together with the prior calibration of the whole measuring equipment in the laboratory, an overall uncertainty of the target values (COP, JAZ) of 10% was achieved

Field Performance Of Domestic Heat Pumps For Heating And Hot Water In Switzerland Part II: Results, Analysis And Optimization

This study presents the development, the methods, and the state of the art of heat pump field trials as they are currently carried out by the Heat Pump Test Center (WPZ) in Buchs SG, Switzerland. In the current study, heat pumps for hydronic heating systems in single family houses within Switzerland have been investigated since 2016. So far, over 20 air-source and geothermal heat pumps have been added to this governmental quality assurance program (Swiss Federal authority EnergieSchweiz). For each heat pump system, more than 40 measured variables are recorded at a time interval of 10 s using calibrated sensors with very low measurement uncertainty. The aim of this field study is to record the real system efficiency in operation and to draw comparisons with characteristic values from laboratory measurements and manufacturer data. The study presented is divided into two parts. The first part entitled “Technology, Methods and State of the Art of the field studies” focuses on the procedure and measuring technology of field studies performed at WPZ Buchs. The second part is entitled “Results, Analysis and Optimization of current field studies” and presents meaningful results of the current field study as well as identification and optimization of possible deficiencies in the planning, installation and handling of the investigated heat pump systems. Heat pumps installed in new and refurbished buildings have been investigated with different system boundaries. In terms of performance, the current study shows an average annual coefficient of performance (SPF) of 3.6 and a span from 3.5 to 3.7 for floor heating and domestic hot water production using air/water heat pumps. Geothermal heat pump systems reach an average annual coefficient of performance of almost 5. Although the systems are running quite satisfying overall, the results also show considerable differences between the systems as well as typical mistakes in the installation and handling of the heat pumps. A controller that does not work optimally in terms of application and consumption is a frequently found cause of decreased performance. After evaluating the baseline performance for two years, the systems are optimized to increase performance and avoid poor operation. The collected data is also used to better define guidelines for planner and installers

Design for success: Identifying a process for transitioning to an intensive online course delivery model in health professions education.

Intensive courses (ICs), or accelerated courses, are gaining popularity in medical and health professions education, particularly as programs adopt e-learning models to negotiate challenges of flexibility, space, cost, and time. In 2014, the Department of Clinical Research and Leadership (CRL) at the George Washington University School of Medicine and Health Sciences began the process of transitioning two online 15-week graduate programs to an IC model. Within a year, a third program also transitioned to this model. A literature review yielded little guidance on the process of transitioning from 15-week, traditional models of delivery to IC models, particularly in online learning environments. Correspondingly, this paper describes the process by which CRL transitioned three online graduate programs to an IC model and details best practices for course design and facilitation resulting from our iterative redesign process. Finally, we present lessons-learned for the benefit of other medical and health professions\u27 programs contemplating similar transitions. ABBREVIATIONS: CRL: Department of Clinical Research and Leadership; HSCI: Health Sciences; IC: Intensive course; PD: Program director; QM: Quality Matters

Developmental conduction aphasia after neonatal stroke

Objective Impairment of speech repetition following injury to the dorsal language stream is a feature of conduction aphasia, a well-described “disconnection syndrome” in adults. The impact of similar lesions sustained in infancy has not been established. Methods We compared language outcomes in term-born individuals with confirmed neonatal stroke (n = 30, age = 7–18 years, left-sided lesions in 21 cases) to matched controls (n = 40). Injury to the dorsal and/or ventral language streams was assessed using T1- and T2-weighted magnetic resonance imaging (MRI) and diffusion tractography. Language lateralization was determined using functional MRI. Results At the group level, left dorsal language stream injury was associated with selective speech repetition impairment for nonwords (p = 0.021) and sentences (p < 0.0001). The majority of children with significant repetition impairment had retained left hemisphere language representation, but right hemisphere dominance was correlated with minimal or absent repetition deficits. Post hoc analysis of the repetition-impaired group revealed additional language-associated deficits, but these were more subtle and variable. Interpretation We conclude that (1) despite the considerable plasticity of the infant brain, early dorsal language stream injury can result in specific and long-lasting problems with speech repetition that are similar to the syndrome of conduction aphasia seen in adults; and (2) language reorganization to the contralateral hemisphere has a protective effect. Ann Neurol 2018;83:664–675 Ann Neurol 2018;83:664–67

Nonclassical statistics of intracavity coupled χ(2)\chi^{(2)} waveguides: the quantum optical dimer

A model is proposed where two $\chi^{(2)}$ nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These violations are particularly strong when two instabilities are competing, where twin-beam behavior is found as almost complete noise suppression in the difference of the fundamental intensities. Moreover, close to bistable transitions perfect twin-beam correlations are seen in the sum of the fundamental intensities, and also the self-pulsing instability as well as the transition from symmetric to asymmetric states display nonclassical twin-beam correlations of both fundamental and second-harmonic intensities. The results are based on the full quantum Langevin equations derived from the Hamiltonian and including cavity damping effects. The intensity correlations of the output fields are calculated semi-analytically using a linearized version of the Langevin equations derived through the positive-P representation. Confirmation of the analytical results are obtained by numerical simulations of the nonlinear Langevin equations derived using the truncated Wigner representation.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

Fingerprints of Kitaev physics in the magnetic excitations of honeycomb iridates

In the quest for realizations of quantum spin liquids, the exploration of Kitaev materials - spin-orbit entangled Mott insulators with strong bond-directional exchanges - has taken center stage. However, in these materials the local spin-orbital j=1/2 moments typically show long-range magnetic order at low temperature, thus defying the formation of a spin-liquid ground state. Using resonant inelastic x-ray scattering (RIXS), we here report on a proximate spin liquid regime with clear fingerprints of Kitaev physics in the magnetic excitations of the honeycomb iridates alpha-Li2IrO3 and Na2IrO3. We observe a broad continuum of magnetic excitations that persists up to at least 300K, more than an order of magnitude larger than the magnetic ordering temperatures. We prove the magnetic character of this continuum by an analysis of the resonance behavior. RIXS measurements of the dynamical structure factor for energies within the continuum show that dynamical spin-spin correlations are restricted to nearest neighbors. Notably, these spectroscopic observations are also present in the magnetically ordered state for excitation energies above the conventional magnon excitations. Phenomenologically, our data agree with inelastic neutron scattering results on the related honeycomb compound RuCl3, establishing a common ground for a proximate Kitaev spin-liquid regime in these materials.Comment: 13 pages, 14 figure