Statistical Image Reconstruction for High-Throughput Thermal Neutron Computed Tomography

Neutron Computed Tomography (CT) is an increasingly utilised non-destructive analysis tool in material science, palaeontology, and cultural heritage. With the development of new neutron imaging facilities (such as DINGO, ANSTO, Australia) new opportunities arise to maximise their performance through the implementation of statistically driven image reconstruction methods which have yet to see wide scale application in neutron transmission tomography. This work outlines the implementation of a convex algorithm statistical image reconstruction framework applicable to the geometry of most neutron tomography instruments with the aim of obtaining similar imaging quality to conventional ramp filtered back-projection via the inverse Radon transform, but using a lower number of measured projections to increase object throughput. Through comparison of the output of these two frameworks using a tomographic scan of a known 3 material cylindrical phantom obtain with the DINGO neutron radiography instrument (ANSTO, Australia), this work illustrates the advantages of statistical image reconstruction techniques over conventional filter back-projection. It was found that the statistical image reconstruction framework was capable of obtaining image estimates of similar quality with respect to filtered back-projection using only 12.5% the number of projections, potentially increasing object throughput at neutron imaging facilities such as DINGO eight-fold

Susceptibility of personal computer systems to electromagnetic pulses with double exponential character

In this paper the susceptibility of personal computer systems to fast transient electromagnetic pulses with double exponential pulse shapes (EMP, UWB) is determined. The influence of the computer generation, RAM-values, different program states and the pulse shape, as well as the destruction thresholds of single PC-components (CPU, RAM, BIOS, Mainboard) have been investigated. © 2004 Copernicus GmbH.Armed Forces Scientific Institute for Protection Technologies – ABC-Protection (Munster, Germany

School Lunch Participation and Youth School Failure: A Multi-Racial Perspective

In the United States, students from low-socioeconomic status and minority ethnic groups graduate from high school at lower rates than their peers. Limited studies exist about the risk and protective factors that affect the disproportionate graduation rates by income and ethnicity. Using the 2016 Arizona Youth Survey data (N = 32,178), this study aims to explore the relationship between the National School Lunch Program (NSLP) participation and school failure, and other risk and protective factors from a multi-racial perspective. Logistic regressions were conducted on the total sample and the six ethnic subsamples (i.e., White, Latino, Black, American Indian, Asian/Pacific Islander, and Mixed). Results showed a significant difference in school failure between free lunch participants and nonparticipants for the total youth sample and for the White, Latino, Black and Mixed subsamples. However, a significant difference in school failure between free lunch participants and reduced price lunch participants was only found for the total sample but not for any of the six ethnic subsamples. Significant risk factors across most ethnic groups include the participant being suspended from school and peer suspension/dropout. Protective factors across most ethnic groups were family management and school commitment. Findings highlight the need for more culturally responsive interventions to target school failure for low-income students across ethnic groups

Critical Quantum Metrology with a Finite-Component Quantum Phase Transition

Physical systems close to a quantum phase transition exhibit a divergent susceptibility, suggesting that an arbitrarily high precision may be achieved by exploiting quantum critical systems as probes to estimate a physical parameter. However, such an improvement in sensitivity is counterbalanced by the closing of the energy gap, which implies a critical slowing down and an inevitable growth of the protocol duration. Here, we design different metrological protocols that exploit the superradiant phase transition of the quantum Rabi model, a finite-component system composed of a single two-level atom interacting with a single bosonic mode. We show that, in spite of the critical slowing down, critical quantum optical probes can achieve a quantum-enhanced time scaling of the sensitivity in frequency-estimation protocols

Shielding of electronic systems against transient electromagnetic interferences

In order to protect electronic systems against the effects of transient electromagnetic interferences, shields made of electrically conductive material can be used. The subject of this paper is an electrically conductive textile. When applying the shield, a reliable measure is needed in order to determine the effectiveness of the shield to protect against electromagnetic pulses. For this purpose, a time domain measurement technique is presented using double exponential pulses. With these pulses, the susceptibility of an operating electronic device with and without the shield is determined. As a criterion of quality of a shield, the breakdown failure rate found in both cases is compared. © 2004 Copernicus GmbH

Fault tree analysis for system modeling in case of intentional EMI

The complexity of modern systems on the one hand and the rising threat of intentional electromagnetic interference (IEMI) on the other hand increase the necessity for systematical risk analysis. Most of the problems can not be treated deterministically since slight changes in the configuration (source, position, polarization, ...) can dramatically change the outcome of an event. For that purpose, methods known from probabilistic risk analysis can be applied. One of the most common approaches is the fault tree analysis (FTA). The FTA is used to determine the system failure probability and also the main contributors to its failure. In this paper the fault tree analysis is introduced and a possible application of that method is shown using a small computer network as an example. The constraints of this methods are explained and conclusions for further research are drawn

Portable inhalation systemfor a dosed insulin supply

Интенсивная инсулинотерапия необходима для контроля состояния пациентов с диабетом.Несмотря на постоянное усовершенствование инсулинотерапии, все ещ? существует проблема неудобства режимов многократных инъекций инсулина. Целью данной работы является создание системы, позволяющей осуществлять ингаляцию инсулина.Intensive insulin therapy is necessary for the control of a condition diabetic patients. Despite the constant improvement of insulin therapy, there is still the problem of discomfort repeated regimes of insulin injections. The objective of this work is to create a system that allows the inhalation of insulin

Exploring patterns of recurrent melanoma in Northeast Scotland to inform the introduction a digital self-examination intervention

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