Spatial relations, histories from below and the makings of agency: Reflections on The Making of the English Working Class at 50

In this paper we propose a conversation between work in labour history and labour geography, in part centring on the formative contribution of E.P. Thompson. We contend that the commitment to multiple and political forms of agency and working-class experience and the positioning of class as process, which are lasting contributions of The Making of the English Working Class, offer resources for re-invigorating debates on agency within labour geography and beyond. The paper scrutinizes the spatial politics at work in Thompson’s account of agency and experience through drawing on critiques of Thompson by feminist and post-colonial scholars. The paper explores the significance of Thompson’s work for asserting a spatial politics of labour and argues for attention to the diverse agentic spatial practices shaped through labour organizing and struggles. The paper concludes by setting out some key aspects of the terms of a conversation between labour geographies and labour histories

Selected microgravity combustion diagnostic techniques

During FY 1989-1992, several diagnostic techniques for studying microgravity combustion have moved from the laboratory to use in reduced-gravity facilities. This paper discusses current instrumentation for rainbow schlieren deflectometry and thermophoretic sampling of soot from gas jet diffusion flames

Communication System For Firefighters

Currently firefighters use two-way radios to communicate on the job, and they are forced to write reports based on their memory because there is not an easy way to record the communications between two-way radios. Firefighters need a system to automatically document what happened while they were responding to a call. To save them a significant amount of time when creating reports, our solution is to implement an application that allows firefighters to take pictures, record video and communicate in real time with their team of on-site responders. The proposed system will use a Wireless Local Area Network (WLAN) hosted on the fire truck itself to act as an access point (AP) to which the firefighters can connect. This AP will also save communication between firefighters to a local storage location. Upon return to the fire station, the AP will route all of the information stored locally to a larger database. For now, Wi-Fi will be our communication medium, with a prediction that our technology can eventually be extended to include radio signal

Doppler radar with multiphase modulation of transmitted and reflected signal

A microwave radar signal is generated and split by a circulator. A phase shifter introduces a series of phase shifts into a first part of the split signal which is then transmitted by antenna. A like number of phase shifts is introduced by the phase shifter into the return signal from the target. The circulator delivers the phase shifted return signal and the leakage signal from the circulator to a mixer which generates an IF signal output at the Doppler frequency. The IF signal is amplified, filtered, counted per unit of time, and the result displayed to provide indications of target sense and range rate. An oscillator controls rate of phase shift in the transmitted and received radar signals and provides a time base for the counter. The phase shift magnitude increases may be continuous and linear or discrete functions of time

Laser cooling with a single laser beam and a planar diffractor

A planar triplet of diffraction gratings is used to transform a single laser beam into a four-beam tetrahedral magneto-optical trap. This `flat' pyramid diffractor geometry is ideal for future microfabrication. We demonstrate the technique by trapping and subsequently sub-Doppler cooling 87Rb atoms to 30microKelvin.Comment: 3 pages, 4 figure

The analysis of rigid-viscoplastic plane structures subjected to large impulsive loading

This thesis is concerned with the analysis of plane ductile beams and frames which are subjected to large impulsive loading. The elastic response is ignored, and the material is considered as rigidviscoplastic in order to take rate effects into account. Computational advantage is obtained by modelling this behaviour by a homogeneous viscous constitutive relation, as the rigid phase is absent. As opposed to the standard displacement method finite element formulation where interpolation functions describing the velocity field across elements are given, a formulation is used in which nodal velocities, moments and element axial forces are carried as parameters. Three methods of analysis are presented; firstly, the mode approximation technique is described, where the actual behaviour of the structure is approximated in closed form by the product of a mode shape and a function of time. A new algorithm for the determination of the mode shape is presented. The mode technique is then extended to include geometric effects by means of the instantaneous mode solution technique. Secondly, a method is given whereby at each instant the accelerations (by the Tamuzh principle) and the rates of change of moment (by virtual velocities formulation) are found, and velocities and moments are integrated forward independently to obtain a solution. Finally, a direct method of analysis is described, where nodal forces conjugate to a given velocity field are calculated (by the principle of virtual velocities), and hence from the equations of motion, accelerations are determined. An implicit forward integration scheme is employed to advance the solution in time. Illustrative examples are presented which show that these techniques give very good and computationally efficient predictions of the displaced shape of the structures under consideration, even when displacements are in the order of the dimensions of the structure

Laser cooling and loading of Rb into a large period, quasi-electrostatic, optical lattice

This thesis reports on the design and construction of, and results from, an optical-dipole trapping apparatus developed to confine ultracold rubidium atoms in a conservative, large period, optical-dipole trap. An ultra-high vacuum system was designed and constructed to create a very low- background pressure. A new technique of viewport construction was developed, allowing for the fabrication of economical, high-quality windows for transmission of mid-infra-red laser radiation. The construction of a magneto-optical trap (MOT) and an optical molasses, and the subsequent characterisation, are discussed. A theory for the ac-Stark shift of atoms in a far-detuned laser field was developed. The nature of the scalar and tensorial light-shifts of the ground and first excited states of alkali atoms - the 5s(^2)S1/2 and 5p(^2)P3/2 states of Rb - has been examined. The effect of the differential light-shifts between these states on the operation of efficient laser cooling is discussed. A quasi-electrostatic dipole trap (QUEST) was formed from 50 W of CO2 laser power (٢ = 10.6 μm), focussed to <100 μm. The transfer of ultra-cold atoms from the MOT and optical molasses to the QUEST have been examined. Single beam and standing wave geometries of the QUEST have been implemented, with lifetimes of many seconds. The theory for the ac-Stark effect due to a single laser field has been further developed to consider orthogonally polarised fields with independent wavelengths. The use of an auxiliary laser field, a Nd:YAG laser at λ = 1.064 μm, to enhance the number and density of atoms loaded into the QUEST has been proposed and realised