Gas Metal Arc /GMA/ weld torch proximity control

Adjustable transducer probe, which is attached to a welding torch and maintains a preset touch-to-work distance, accurately follows irregular surfaces, is less sensitive to heat and static interference, and has more positive response because of electro-mechanical control

Technology-rich modelling of micro combined heat and power for economic, environmental, and policy assessment

Imperial Users onl

Numerical methods for coupled reconstruction and registration in digital breast tomosynthesis.

Digital Breast Tomosynthesis (DBT) provides an insight into the fine details of normal fibroglandular tissues and abnormal lesions by reconstructing a pseudo-3D image of the breast. In this respect, DBT overcomes a major limitation of conventional X-ray mam- mography by reducing the confounding effects caused by the superposition of breast tissue. In a breast cancer screening or diagnostic context, a radiologist is interested in detecting change, which might be indicative of malignant disease. To help automate this task image registration is required to establish spatial correspondence between time points. Typically, images, such as MRI or CT, are first reconstructed and then registered. This approach can be effective if reconstructing using a complete set of data. However, for ill-posed, limited-angle problems such as DBT, estimating the deformation is com- plicated by the significant artefacts associated with the reconstruction, leading to severe inaccuracies in the registration. This paper presents a mathematical framework, which couples the two tasks and jointly estimates both image intensities and the parameters of a transformation. Under this framework, we compare an iterative method and a simultaneous method, both of which tackle the problem of comparing DBT data by combining reconstruction of a pair of temporal volumes with their registration. We evaluate our methods using various computational digital phantoms, uncom- pressed breast MR images, and in-vivo DBT simulations. Firstly, we compare both iter- ative and simultaneous methods to the conventional, sequential method using an affine transformation model. We show that jointly estimating image intensities and parametric transformations gives superior results with respect to reconstruction fidelity and regis- tration accuracy. Also, we incorporate a non-rigid B-spline transformation model into our simultaneous method. The results demonstrate a visually plausible recovery of the deformation with preservation of the reconstruction fidelity

Performance assessment of tariff-based air source heat pump load shifting in a UK detached dwelling featuring phase change-enhanced buffering

Using a detailed building simulation model, the amount of thermal buffering, with and without phase change material (PCM), needed to time-shift an air source heat pump's operation to off-peak periods, as defined by the UK 'Economy 10' tariff, was investigated for a typical UK detached dwelling. The performance of the buffered system was compared to the case with no load shifting and with no thermal buffering. Additionally, the load shifting of a population of buffered heat pumps to off-peak periods was simulated and the resulting change in the peak demand on the electricity network was assessed. The results from this study indicate that 1000 L of hot water buffering or 500 L of PCM-enhanced hot water buffering was required to move the operation of the heat pump fully to off-peak periods, without adversely affecting the provision of space heating and hot water for the end user. The work also highlights that buffering and load shifting increased the heat pump's electrical demand by over 60% leading to increased cost to the end user and increased CO2 emissions (depending on the electricity tariff applied and time varying CO2 intensity of the electricity generation mix, respectively). The study also highlights that the load-shifting of populations of buffered heat pumps wholly to off-peak periods using crude instruments such as tariffs increased the peak loading on the electrical network by over 50% rather than reducing it and that careful consideration is needed as to how the load shifting of a group of heat pumps is orchestrated

Finding the "Early Medieval" in South Asian Archaeology

The concept of an “early medieval” period (c. 600–1300 c.e.) in the study of South Asia’s past is well established, yet remains ill defined and poorly understood. As a result, debates regarding grand explanative frameworks, not to mention the meaning and use of the term medieval, have dominated the study of the period. Important though these concerns are, what underpins them, and something that is rarely considered, is how sources and methodologies affect the study of the period. Historiographic review of scholarship on the early medieval reveals that from its inception, the period has been studied exclusively through the examination of documentary sources and monumental remains within the fields of history, literary and religious studies, and art history. Archaeology has been used to support historical theories, largely in order to provide further empirical “proof ” of a perceived decline in trade and urbanism. The continued use of archaeological evidence in this way has meant that the full potential of archaeological inquiry has not been fulfilled, and the impetus for new archaeological research has been stifled. As a result, the early medieval is arguably the most poorly represented period archaeologically in the entire subcontinent. Critical assessment of the limited amount of archaeological evidence that does exist reveals a number of methodological and theoretical concerns that bring into question its applicability and use. These shortcomings not only force one to question historical interpretations, but also limit what can be said, archaeologically, about the period. It is argued that many of the wider uncertainties surrounding the definition and meaning of the early medieval stem from this absence of archaeological research. What is urgently needed is a revitalization of the archaeological approach to the study of the period; some ways are suggested in which this might be achieved in terms of methodological approaches, and questions that could be asked

MEASURING NET BENEFITS RESULTING FROM UNIVERSITY-INDUSTRY COLLABORATION: AN EXAMPLE FROM THE NEW MEXICO CHILE TASK FORCE

Research and Development/Tech Change/Emerging Technologies,