Multipole charge conservation and implications on electromagnetic radiation

It is shown that conserved charges associated with a specific subclass of gauge symmetries of Maxwell electrodynamics are proportional to the well known electric multipole moments. The symmetries are residual gauge transformations surviving after fixing the Lorenz gauge, and have nontrivial charge. These "Multipole charges" receive contributions both from the charged matter and electromagnetic fields. The former is nothing but the electric multipole moment of the source. In a stationary configuration, there is a novel equipartition relation between the two contributions. The multipole charge, while conserved, can freely interpolate between the source and the electromagnetic field, and therefore can be propagated with the radiation. Using the multipole charge conservation, we obtain infinite number of constraints over the radiation produced by the dynamics of charged matter.Comment: 21 pages, 2 figures; v2: section 4.2 added, minor correction

Design and performance assessment for a novel friction smoke generator : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Chemical and Bioprocessing at Massey University, Palmerston North, New Zealand

Figures 2.1, 2.2, 2.3, 2.4, 2.6, 2.7, 2.8, 2.9, 2.11, 2.14, 2.15 & 2.16 have been removed for copyright reasons but may be accessed via their source listed in the References.Friction is one of the methods used to generate smoke for food smoking applications. The method involves pressing a plank of wood against a spinning wheel, roughened to provide frictional heating. The heating raises the interface temperature above 240 °C, where smouldering occurs. The primary objective of this project was to understand the dynamics of a novel friction smoke generator, designed in a prior project, but optimised here. Subobjectives included understanding the frictional system and its thermodynamic behaviour, and preliminary attempts to define the composition of the smoke. The novel aspect of the design is supplementary heating additional to the heat generated by friction. This means the interface temperature is less dependent on frictional heating. A system control strategy was developed to control temperature and force. Twenty seven experiments were carried out. Nine of them investigated the smouldering limits without supplementary heating for various pressing forces and sliding speeds. The other twelve runs were conducted with supplementary heating for 100, 150 and 200 ˚C and various forces at constant sliding speed. The last six experiments were selected runs from the previous experiments where smoke was collected for composition analysis. With no supplementary heating, pyrolysis takes place when the pressing force is ≥49.1 N and the wheel speed is at ≥2500 rpm. These conditions generate interfacial temperatures within the pyrolysis range. When the system was heated, the limit where smouldering starts when 9.81 N and 200 ˚C were applied. Two significant results were obtained. First, the progression of smouldering, resulted in a low and high wear rate of wood. The shift between these is proposed to be an endothermic to exothermic transition. Second, the time to reach this shift is a function of the pressing force and system temperature, becoming instantaneous at 200°C for forces > 29.4 N. These allowed insight to be gained into the dynamics of heat and mass transfer during friction smoking. The smoke composition analysis indicates that controlling the volatiles formation is highly achievable by varying the smoking conditions (i.e. auxiliary heat, pressing force). The current design has some limitations, which include uncertainties in the conversion of electrical to mechanical power, vibration of the wood plank, conduction along the motor shaft and ingress of air. Recommendations are to address these by placing a thermal break on the shaft, preventing ambient air ingress into the chamber and adding a torque transducer. Further study is also recommended on the roughness and design of the friction wheel, and on scale up

Gender, mentoring and social capital in the National Health Service (NHS) in Scotland, UK

This chapter investigates the role of gender, mentoring and social capital and contributes to literature about the career development of women in senior management roles in the National Health Service of the UK. It draws on a doctoral study of senior-level managers in a Scottish NHS Board. The data collected are: (i) documentary; (ii) quantitative; and (iii) qualitative. The quantitative data are collected through questionnaires, while the source of qualitative data is in-depth semi-structured interviews. The doctoral study is embedded within an interpretivist and feminist paradigm. Although access to mentoring and social capital was seen as likely to enhance the career progression of females to senior managerial roles, gendered work and family expectations, gendered organisational culture, and normative performances of gendered senior management were identified as obstacles in taking advantages of mentoring and social capital. To the best of our knowledge, this is the only piece of work that explicitly investigates the role of mentoring and social capital in managing gender diversity at the senior managerial positions of the NHS

Gravitational multipole moments from Noether charges

We define the mass and current multipole moments for an arbitrary theory of gravity in terms of canonical Noether charges associated with specific residual transformations in canonical harmonic gauge, which we call multipole symmetries. We show that our definition exactly matches Thorne's mass and current multipole moments in Einstein gravity, which are defined in terms of metric components. For radiative configurations, the total multipole charges -- including the contributions from the source and the radiation -- are given by surface charges at spatial infinity, while the source multipole moments are naturally identified by surface integrals in the near-zone or, alternatively, from a regularization of the Noether charges at null infinity. The conservation of total multipole charges is used to derive the variation of source multipole moments in the near-zone in terms of the flux of multipole charges at null infinity.Comment: v1: 22 pages + 13 pages of appendices, 1 figure; v2: published version in JHE

Teaching Engineering Ethics in the Classroom through a Town Hall Meeting Activity

Engineers often contribute to projects that impact many people and have ethical implications. Some may even move to a career of political advocacy and policy-making. However, most engineering curricula have a strongly technical focus and do not require students to think critically about ethical issues related to engineering. To bridge this gap, we developed a classroom-based town hall meeting activity that demonstrates the ethical issues that may arise when engineers are advocating for or helping craft public policies. Our town hall meeting scenario, which was set in a fictional tourist town called Rainbow Town, divided a class of twenty engineering students into groups of engineers, politicians, and voters. There were two opposing political groups and two engineering groups with competing interests. The voters had individual characters with varying careers and objectives. The town hall meeting was a debate on whether Rainbow Town should undertake a construction project that would bring jobs to the city, but could potentially adversely impact fish population at the town’s natural heritage site, the main source of income for the town. The objective of the activity varied based on what role each student was playing. The politicians’ job was to further the objectives of their own party while simultaneously keeping their voter base happy. The engineers’ job was to help voters make an informed decision about which policy (or party) to vote for, while helping politicians craft the right policy. The voters’ job was to protect their own livelihoods. Despite the simplicity of the town hall meeting scenario, the students wholeheartedly donned the mantle of their assigned role, taking the objectives of their role seriously. At the post-activity debrief, students commented that the activity was harder on the engineers since they had to prove everything with facts, but the politician groups did not.Cockrell School of Engineerin

Near Horizon Extremal Geometry Perturbations: Dynamical Field Perturbations vs. Parametric Variations

In arXiv:1310.3727 we formulated and derived the three universal laws governing Near Horizon Extremal Geometries (NHEG). In this work we focus on the Entropy Perturbation Law (EPL) which, similarly to the first law of black hole thermodynamics, relates perturbations of the charges labeling perturbations around a given NHEG to the corresponding entropy perturbation. We show that field perturbations governed by the linearized equations of motion and symmetry conditions which we carefully specify, satisfy the EPL. We also show that these perturbations are limited to those coming from difference of two NHEG solutions (i.e. variations on the NHEG solution parameter space). Our analysis and discussions shed light on the "no-dynamics" statements of arXiv:0906.2380 and arXiv:0906.2376.Comment: 38 page

Cerebral Synchrony Assessment Tutorial: A General Review on Cerebral Signals' Synchronization Estimation Concepts and Methods

The human brain is ultimately responsible for all thoughts and movements that the body produces. This allows humans to successfully interact with their environment. If the brain is not functioning properly many abilities of human can be damaged. The goal of cerebral signal analysis is to learn about brain function. The idea that distinct areas of the brain are responsible for specific tasks, the functional segregation, is a key aspect of brain function. Functional integration is an important feature of brain function, it is the concordance of multiple segregated brain areas to produce a unified response. There is an amplified feedback mechanism in the brain called reentry which requires specific timing relations. This specific timing requires neurons within an assembly to synchronize their firing rates. This has led to increased interest and use of phase variables, particularly their synchronization, to measure connectivity in cerebral signals. Herein, we propose a comprehensive review on concepts and methods previously presented for assessing cerebral synchrony, with focus on phase synchronization, as a tool for brain connectivity evaluation

Pedagogic strategies to support practice learning in specialised clinical learning environments: A Grounded Theory Approach.

The aims of my study were to explore and identify, from the experiences of mentors and mentees, the ways specialised clinical learning environments are constructed and the potential impact this has on practice learning; learn about the effects that pedagogic strategies have on the mentor/mentee relationship, to engage with clinical practice and the use of learning strategies to maximise practice learning that support and enable students to translate practice and vice versa. The literature review demonstrated that mentoring in nursing is wide ranging and provided a strong rationale for this thesis to explore pedagogy in specialised clinical learning environments. Grounded theory methodology was used for this research study. The ethical considerations associated with this methodology, the participant selection, the sampling process, data collection and analysis and issues of data credibility and the concept of trustworthiness in grounded theory were also explored. Two main codes emerged from the data analysis of 11 in-depth interviews: Transaction’ and ‘Motivation’. There were also three sub codes: ‘Value’, ‘Culture’ and ‘Engaging’. The findings suggest that the relationship between mentors and mentees in the clinical learning environment was a mutual collaboration and exchange, which was developmental on both a personal and professional level. A substantive theory emerged: ‘Transactional Motivation’ which will contribute to the body of existing knowledge and provide an opportunity to generate further research into other relevant areas of clinical practice. The theory will also contribute a significantly innovative dimension to the theories of humanistic learning and introduce a new debate to the construct of mentoring in specialised clinical learning environments