Nonperturbative Approach to Circuit Quantum Electrodynamics

We outline a rigorous method which can be used to solve the many-body Schroedinger equation for a Coulomb interacting electronic system in an external classical magnetic field as well as a quantized electromagnetic field. Effects of the geometry of the electronic system as well as the polarization of the quantized electromagnetic field are explicitly taken into account. We accomplish this by performing repeated truncations of many-body spaces in order to keep the size of the many particle basis on a manageable level. The electron-electron and electron-photon interactions are treated in a nonperturbative manner using "exact numerical diagonalization". Our results demonstrate that including the diamagnetic term in the photon-electron interaction Hamiltonian drastically improves numerical convergence. Additionally, convergence with respect to the number of photon states in the joint photon-electron Fock space basis is fast. However, the convergence with respect to the number of electronic states is slow and is the main bottleneck in calculations.Comment: Revtex, pdflatex, 8 pages, with 5 included pdf figure

Content Analysis of Four Fear of Falling Rating Scales by Linking to the International Classification of Functioning, Disability and Health.

OBJECTIVE: To gain a deeper understanding of the content of 4 fear of falling (FOF) rating scales by linking them to the International Classification of Functioning, Disability and Health (ICF). DESIGN: Linking study according to the ICF linking rules. SETTING: Not applicable. PATIENTS: Not applicable. METHODS: The rating scales were the Falls Efficacy Scale-International (FES-I), the Swedish version of the Falls Efficacy Scale (FES[S]), the Activities-specific Balance Confidence Scale (ABC), and the modified Survey of Activities and Fear of Falling in the Elderly (SAFFE). The process followed the established and updated linking rules. Three linkers independently identified all meaningful concepts in the rating scales and linked them to the most precise ICF categories. The linkers then discussed their results to reach consensus. If consensus was not attained, the linkers pursued the discussions with a fourth person to reach consensus. MAIN OUTCOME MEASUREMENTS: Not applicable. RESULTS: Most meaningful concepts from the overall questions were linked to the ICF component of body functions. Of the 62 items, all but one meaningful concept were linked to the component of activities and participation. All 4 rating scales covered the chapters of mobility and domestic life and had most linkages to the mobility chapter. CONCLUSIONS: The linking process revealed similarities and differences between the 4 FOF rating scales, as well as methodologic challenges in linking instruments to the ICF. By providing a content description that allows for a direct comparison of the rating scales, the results may be helpful when choosing an appropriate rating scale assessing FOF in clinical practice and research. A further head-to-head comparison through psychometric analyses is required to recommend appropriate FOF rating scales. Studies are also needed to investigate how the overall question and response categories of a rating scale affect respondents' answers

Energy reduction by power loss minimisation through wheel torque allocation in electric vehicles: a simulation-based approach

As vehicles become increasingly electrified, electrical machines for propulsion can be divided into many sources making the vehicle highly over-actuated. For over-actuated vehicles, the allocation of a propulsive force is an underdetermined process with respect to both the number of wheels and electrical machines. Hence, the allocation can be made to favour particular attributes such as energy consumption. In this study, a vehicle equipped with four identical electric motors with a fixed transmission ratio connected through a half-shaft and a coupling to one wheel respectively is driven a 2-h-long city cycle in the vicinity of G\uf6teborg. Two different control allocation methods are presented to distribute torque momentaneously based on driver request while minimising power losses in electric motor and inverter as well as tyres. One method is a quadratic programming optimisation and the other is an offline exhaustive search method resulting in a look-up table based on requested torque and actual speed. The two methods are compared to other torque distribution strategies based on fixed distribution ratio and equal tyre-to-road friction utilisation. It was found that using the developed optimisation algorithms, a reduction of up to 3.9% in energy consumption can be obtained

Compendium in Vehicle Motion Engineering

This compendium is written for the course “MMF062 Vehicle Motion Engineering” at Chalmers University of Technology. The compendium covers more than included in that course; both in terms of subsystem designs and in terms of some teasers for more advanced studies of vehicle dynamics. Therefore, it is also useful for the more advanced courses, such as “TME102 Vehicle Modelling and Control”.The overall objective of the compendium is to educate engineers that understand and can contribute to development of good motion and energy functionality of vehicles. The compendium focuses on road vehicles, primarily passenger cars and commercial vehicles. Smaller road vehicles, such as bicycles and single-person cars, are only very briefly addressed. It can be mentioned that there exist a lot of ground-vehicle types not covered at all, such as: off-road/construction vehicles, tracked vehicles, horse wagons, hovercrafts, and railway vehicles.Functions are needed for requirement setting, design and verification. The overall order within the compendium is that models/methods/tools needed to understand each function are placed before the functions. Chapters 3-5 describes (complete vehicle) “functions”, organised after vehicle motion directions:\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 3:\ua0Longitudinal\ua0dynamics\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 4:\ua0Lateral\ua0dynamics\ub7\ua0\ua0\ua0\ua0\ua0\ua0\ua0\ua0 Chapter 5:\ua0Vertical\ua0dynamicsChapter 1 introduces automotive industry and the overall way of working there and defines required pre-knowledge from “product-generic” engineering, e.g. modelling of dynamic systems.Chapter 2 also describes the subsystems relevant for vehicle dynamics:• Wheels and Tyre\ua0• Suspension\ua0• Propulsion\ua0• Braking System\ua0• Steering System\ua0• Environment Sensing SystemThe compendium is released in a new version each year, around October, which is the version your read now. A "latest draft" is more frequently updated and often includes some more, sometimes unfinished, material: https://chalmersuniversity.box.com/s/6igaen1ugcjzuhjziuon08axxiy817f

Reconstruction of Random Colourings

Reconstruction problems have been studied in a number of contexts including biology, information theory and and statistical physics. We consider the reconstruction problem for random $k$-colourings on the $\Delta$-ary tree for large $k$. Bhatnagar et. al. showed non-reconstruction when $\Delta \leq \frac12 k\log k - o(k\log k)$ and reconstruction when $\Delta \geq k\log k + o(k\log k)$. We tighten this result and show non-reconstruction when $\Delta \leq k[\log k + \log \log k + 1 - \ln 2 -o(1)]$ and reconstruction when $\Delta \geq k[\log k + \log \log k + 1+o(1)]$.Comment: Added references, updated notatio

Phase Transition in Ferromagnetic Ising Models with Non-Uniform External Magnetic Fields

In this article we study the phase transition phenomenon for the Ising model under the action of a non-uniform external magnetic field. We show that the Ising model on the hypercubic lattice with a summable magnetic field has a first-order phase transition and, for any positive (resp. negative) and bounded magnetic field, the model does not present the phase transition phenomenon whenever $\liminf h_i> 0$, where ${\bf h} = (h_i)_{i \in \Z^d}$ is the external magnetic field.Comment: 11 pages. Published in Journal of Statistical Physics - 201

Needs for Physical Models and Related Methods for Development of Automated Road Vehicles

Road vehicle automation is a trendy topic in research and media. Some automation such as adaptive cruise control and lane keeping is already on market, while totally driverless vehicles in real everyday transportation tasks is still only a vision. How far the products will reach and when can be debated, but any step forward will benefit of, or need, support of modelling formats and related methods.The presentation will explain typical functional/control architecture for vehicles and then focus on development of the partitions Traffic Situation Management and Vehicle Motion Management, assuming that the partition Environment Observation (image processing etc.) comes in place to a certain known maturity. Models will be used with methods for on-line optimization, on-line predictive simulation, virtual off-line verification for right and faulty function, system safety, simulations for legal assessment of long combination vehicles, etc. A goal for novel methods is that, with physical non-causal models, one can avoid some of the enormous amount of verification simulations needed if only input/output (fixed causality) models are used.Examples from heavy vehicles and passenger cars will be given; what is achieved and what are the challenges for next steps

Evaluation of a Commercial Enzyme Linked Immunosorbent Assay (ELISA) for the Determination of the Neurotoxin BMAA in Surface Waters

The neurotoxin ß-N-methylamino-L-alanine (BMAA) is suspected to play a role in Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Because BMAA seems to be produced by cyanobacteria, surface waters are screened for BMAA. However, reliable analysis of BMAA requires specialized and expensive equipment. In 2012, a commercial enzyme-linked immunosorbent assay (ELISA) for determination of BMAA in surface waters was released. This kit could enable fast and relatively cheap screening of surface waters for BMAA. The objective of this study was to determine whether the BMAA ELISA kit was suitable for the determination of BMAA concentrations in surface waters. We hypothesised that the recovery of spiked samples was close to 100% and that the results of unspiked sample analysis were comparable between ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. However, we found that recovery was higher than 100% in most spiked samples, highest determined recovery was over 400%. Furthermore, the ELISA gave a positive signal for nearly each tested sample while no BMAA could be detected by LC-MS/MS. We therefore conclude that in its current state, the kit is not suitable for screening surface waters for BMAA

First observations of high-temperature submarine hydrothermal vents and massive anhydrite deposits off the north coast of Iceland

High-temperature (250°C) hydrothermal vents and massive anhydrite deposits have been found in a shallow water, sediment-filled graben near 66°36′N in the Tjornes Fracture Zone north of Iceland. The site is located about 30 km offshore, near the small island of Grimsey. The main vent field occurs at a depth of 400 m and consists of about 20 large-diameter (up to 10 m) mounds and 1–3 m chimneys and spires of anhydrite and talc. A north–south alignment of the mounds over a 1-km strike length of the valley floor suggests that their distribution is controlled by a buried fault. Widespread shimmering water and extensive white patches of anhydrite in the sediment between the mounds indicates that the entire 1-km2 area occupied by the vents is thermally active. A 2-man research submersible JAGO was used to map the area and to sample vent waters, gases, and chimneys. Actively boiling hydrothermal vents occur on most of the mounds, and extensive two-phase venting indicates that the field is underlain by a large boiling zone (200×300 m). The presence of boiling fluids in shallow aquifers beneath the deposits was confirmed by sediment coring. The highest-temperature pore fluids were encountered in talc- and anhydrite-rich sedimentary layers that occur up to 7 m below the mounds. Baked muds underlie the talc and anhydrite layers, and pyrite is common in stockwork-like fractures and veins in the hydrothermally altered sediments. However, massive sulfides (pyrite–marcasite crusts) were found in only one relict mound. Subseafloor boiling has likely affected the metal-carrying capacity of the hydrothermal fluids, and deposition of sulfides may be occurring at greater depth. Although the mounds and chimneys at Grimsey resemble other deposits at sedimented ridges (e.g. Middle Valley, Escanaba Trough, Guaymas Basin), the shallow water setting and extensive boiling of the hydrothermal fluids represent a distinctive new type of seafloor hydrothermal system