Development of milli-Kelvin ADR technology for space missions

Cryogenics is increasingly required for space applications as new detector technologies emerge offering improved performance, as is exemplified by future X-ray astronomy missions. The IXO1 (International X-ray Observatory) mission will carry an X-ray Microcalorimeter Spectrometer (XMS), requiring a 50mK operating temperature. Two space-demonstrated technologies are capable of maintaining milli--Kelvin temperatures: Adiabatic Demagnetisation Refrigerators (ADRs) and open-cycle Dilution refrigerators. ADRs are simpler, more reliable, and have a longer lifetime than open-cycle dilution refrigerators which deplete their Helium stores after ~3 years. For long-life (>5 year) missions, ADRs are the best practical choice. MSSL have built an engineering model ADR for the XEUS (X-ray Evolving Universe Spectroscopy) mission. However, the ADR cannot achieve the required hold time and recycle time. This thesis shows how a magnetoresistive heat switch can improve performance such that the required hold time can be achieved. Tungsten Magnetoresistive heat switch technology is developed through experimental investigation. Heat switch performance is found to be a function of purity; the difference between an otherwise identical 99.992% and a 99.999% pure sample is very significant, with switching ratios of 437 and 1×104 respectively at ~4K. The ‘on’ state thermal conductivity is limited by sample size as it is reduced to the electron mean free path and below. A Tungsten magnetoresistive heat switch mounted in the XEUS ADR via bolted joints lined with 0.13mm thick Indium foil can improve its performance to meet the design requirements. MSSL are developing an ADR targeting the IXO XMS. The cooling chain required to support the ADR is presented. The design feasibility and compliance to requirements are verified by thermal and mechanical analyses, and it is shown that the ADR can be supported during holding and recycling for both warm and cold redundancy modes of higher temperature stage coolers in the chain. [1] NOTE: During the writing of this thesis, the IXO mission ceased to be a candidate of the L-class missions under consideration by ESA. However, due to the strong science case of IXO; ESA, Astrium and the scientific community are investigating to what extent a European-led mission could preserve the original science goals of IXO. This new study is ATHENA (Advanced Telescope for High ENergy Astrophysics)

Supporting Positive Outcomes For Youth Involved With The Law

This report reviews literature that helps us understand how to better support positive outcomes for youth involved with the law. The report is meant to serve as a resource and guide for evidence-based practice for programs that work with youth. The report explores the impact of the Youth Criminal Justice Act (YCJA), the legal statute that governs youth justice programs and systems in Canada. The YCJA's emphasis on using extrajudicial measures to divert first-time or less serious and non-violent offenders away from the criminal justice system has successfully shifted the focus of the youth justice system from being more punitive to being more rehabilitative. Nonetheless, the YCJA is only regarded as a "qualified success" because the incarceration rate of Indigenous youth has not decreased, and there have been unintended adverse impacts on youth from racialized groups. This report explores the outcomes of this legislation, reviews "what works" from the literature, and provides recommendations and evidence-based guidelines and principles for practitioners and program developers to support positive outcomes for youth involved with the law

Experiencing Mental Health when Treating Others. Experiences of Mental Health Workers in Relation to Mental Health Problems: Stigma, Perception, and Employment

Introduction: Mental health problems are among the leading causes of disability, with one in four adults in the UK experiencing a mental health disorder. Even with the increasing knowledge concerning mental health disorders, two-thirds of those experiencing concerns are reluctant to disclose their condition and seek professional help. This perceived stigma has a strongly negative correlation with help-seeking behavior, and disproportionately affects healthcare professionals; 26% of mental health professionals in England are reported to be resigning due to a reduction of well-being. Aims: This paper seeks to compare the effects of stigma perceived by mental health and non-mental health professionals, the barriers perceived, and the impact of specific disorders on this stigma. Methods: Using a mixed-methods approach, a survey was conducted to determine the stigma levels and perceived barriers of 108 people; 50% of these participants were professionals working within mental health services. Two focus groups were conducted, one for mental health professionals and one for non-mental health professionals, with four participants in each group. Results: The survey reported that mental health professionals had a lower level of stigma for specific disorders, although male mental health professionals working for less than five years reported a higher level of stigma and perceived barriers than did females with the same experience – with these then reducing after five years. The overarching focus group theme was “changes needed for disclosure”, with each group having four subthemes. Conclusions: Disclosure stigma remains an issue, with further research needing to be conducted to adapt to a minimally stigmatizing service for mental health professionals

Interactive scenario design: The value of flowcharts and schemas in developing scenario-based lessons for online and flexible learning contexts

A web-delivered problem-based scenario was designed for use in a distance education professional development workshop for academics, and also as a stand-alone module. Early scenario design and development was assisted with flowcharts and iterative table-based schemas, which formalised and documented the process before authoring in the e-tool, SBL Interactive. It is well established that such planning techniques can scaffold the course development process. While the flowcharts and schemas described in this paper are designed for use with this tool, the methodology described for their use as planning tools applies generally to the design of interactive electronically-delivered problem-based scenarios. They also allow scenario descriptions and content to be archived and shared in an easily accessible form. The paper illustrates the basic principle that, when designing a course, there are many choices about what, when, where, and how to teach. It provides an account of how conventional design techniques can be used alongside new e-tools to systematically select and optimise the most appropriate instructional blend for a particular learning context

Frequency-Modulated Orocutaneous Stimulation Promotes Non-nutritive Suck Development in Preterm Infants with Respiratory Distress Syndrome or Chronic Lung Disease

Background—For the premature infant, extrauterine life is a pathological condition which greatly amplifies the challenges to the brain in establishing functional oromotor behaviors. The extent to which suck can be entrained using a synthetically patterned orocutaneous input to promote its development in preterm infants who manifest chronic lung disease is unknown. Objective—To evaluate the effects of a frequency-modulated orocutaneous pulse train delivered through a pneumatically-charged pacifier capable of enhancing non-nutritive suck (NNS) activity in tube-fed premature infants. Methods—A randomized trial to evaluate the efficacy of pneumatic orocutaneous stimulation 3x/day on NNS development and length of stay (LOS) in the NICU among 160 newborn infants distributed among 3 subpopulations, including healthy preterm infants (HI), respiratory distress syndrome (RDS), and chronic lung disease (CLD). Study infants received a regimen of orocutaneous pulse trains through a PULSED pressurized silicone pacifier or a SHAM control (blind pacifier) during gavage feeds for up to 10 days. Results—Mixed modeling, adjusted for the infant’s gender, gestational age, postmenstrual age, and birth weight, was used to handle interdependency among repeated measures within subjects. A significant main effect for stimulation mode (SHAM pacifier vs PULSED orosensory) was found among preterm infants for NNS Bursts/minute (p=.003), NNS events/minute (p=.033), and for Total Oral Compressions/minute [NNS+nonNNS] (p=.016). Pairwise comparison of adjusted means using Bonferroni adjustment indicated RDS and CLD infants showed the most significant gains on these NNS performance indices. CLD infants in the treatment group showed significantly shorter LOS by an average of 2.5 days

Frequency-Modulated Orocutaneous Stimulation Promotes Non-nutritive Suck Development in Preterm Infants with Respiratory Distress Syndrome or Chronic Lung Disease

Background—For the premature infant, extrauterine life is a pathological condition which greatly amplifies the challenges to the brain in establishing functional oromotor behaviors. The extent to which suck can be entrained using a synthetically patterned orocutaneous input to promote its development in preterm infants who manifest chronic lung disease is unknown. Objective—To evaluate the effects of a frequency-modulated orocutaneous pulse train delivered through a pneumatically-charged pacifier capable of enhancing non-nutritive suck (NNS) activity in tube-fed premature infants. Methods—A randomized trial to evaluate the efficacy of pneumatic orocutaneous stimulation 3x/day on NNS development and length of stay (LOS) in the NICU among 160 newborn infants distributed among 3 subpopulations, including healthy preterm infants (HI), respiratory distress syndrome (RDS), and chronic lung disease (CLD). Study infants received a regimen of orocutaneous pulse trains through a PULSED pressurized silicone pacifier or a SHAM control (blind pacifier) during gavage feeds for up to 10 days. Results—Mixed modeling, adjusted for the infant’s gender, gestational age, postmenstrual age, and birth weight, was used to handle interdependency among repeated measures within subjects. A significant main effect for stimulation mode (SHAM pacifier vs PULSED orosensory) was found among preterm infants for NNS Bursts/minute (p=.003), NNS events/minute (p=.033), and for Total Oral Compressions/minute [NNS+nonNNS] (p=.016). Pairwise comparison of adjusted means using Bonferroni adjustment indicated RDS and CLD infants showed the most significant gains on these NNS performance indices. CLD infants in the treatment group showed significantly shorter LOS by an average of 2.5 days

Low temperature ignition of biomass

Abstract Biomass is an especially reactive fuel. There have been large increases in the transportation and utilization of biomass fuels over the past 10 years and this has raised concerns over its safe handling and utilization. Fires, and sometimes explosions, are a risk during all stages of fuel production as well as during the handling and utilization of the product. This paper presents a method for assessing ignition risk and provides a ranking of relative risk of ignition of biomass fuels. Tests involved single particle measurements, thermal analysis, dust layer and basket ignition tests. In all cases, smouldering combustion was observed, whereby the fuels pyrolyse to produce a black char, which then subsequently ignites. Low temperature pyrolysis kinetics have been utilised to predict ignition delay times at low temperatures. A method for evaluating risk was explored based on the activation energy for pyrolysis and a characteristic temperature from {TGA} analysis. Here, olive cake, sunflower husk and Miscanthus fall into the high risk category, while the woods, plane, pine, mesquite and red berry juniper, fall into the medium risk category. This method is able to capture the impact of low activation energy for pyrolysis on the increased risk of ignition

Developing content to promote desistance in men who have committed intimate partner violence in same-sex relationships

This article provides an overview of service development processes used to design a therapeutic approach that promotes desistance amongst men who have committed acts of Intimate Partner Violence (IPV) against their male partner or ex-partner. The article aims to explore how inclusive therapeutic service provision can be developed using the best available evidence, stakeholder consultation, co-production and technology. It does so by presenting a two-part study that draws upon a review of inclusive IPV theory alongside responses to a consultation designed to canvas stakeholder opinions (n = 14) of a proposed IPV service. It also provides a case study (n = 1) of the co-production of digital media with someone from the target group for that service. Implications for future service design for marginalised groups in the Criminal Justice System and provisions for people who have committed IPV are discussed. This article represents the views of the authors’ and not those of Her Majesty’s Prison and Probation Service (HMPPS)

Low Temperature Ignition of Biomass

Biomass is an especially reactive fuel. There have been large increases in the transportation and utilisation of biomass fuels over the past 10 years and this has raised concerns over its safe handling and utilisation. Fires, and sometimes explosions, are a risk during all stages of fuel production as well as during the handling and utilisation of the product. This paper presents a method for assessing ignition risk and provides a ranking of relative risk of ignition of biomass fuels. Tests involved single particle measurements, thermal analysis, dust layer and basket ignition tests. In all cases, smouldering combustion was observed, whereby the fuels pyrolyse to produce a black char, which then subsequently ignites. Low temperature pyrolysis kinetics have been utilised to predict ignition delay times at low temperatures. A method for evaluating risk was explored based on the activation energy for pyrolysis and a characteristic temperature from TGA analysis. Here, olive cake, sunflower husk and Miscanthus fall into the high risk category, while the woods, plane, pine, mesquite and red berry juniper, fall into the medium risk category. This method is able to capture the impact of low activation energy for pyrolysis on the increased risk of ignition

Changes in the mechanical properties of biomass wood pellets during artificial degradation in a laboratory environment

In stockpiles exposed to high relative humidity (RH) and rainfall, woody biomass pellets lose structural integrity, often assumed to be due to the uptake of moisture from the environment. In this study three different types of biomass pellet were artificially degraded in a laboratory environment under controlled exposure to RH (10% and 90% RH ) and temperature (range of 10 to 30°C). White, torrefied and steam-exploded wood pellets were investigated. Daily shear tests were conducted with durability and moisture content measured. The exposure of all three pellet types to high RH coupled with elevated temperatures caused a substantial decrease of shear modulus with values of 50% to 92% decrease compared to fresh pellets after 4 days exposure. The steam exploded pellets saw the lowest drop in mechanical durability (5%) but saw the largest decrease in shear modulus, whilst the white wood pellets disintegrated in situ after 4 days. In contrast storage at 10% RH did not cause any observable degradation, with mechanical behaviour of steam exploded and torrefied pellets showing an improvement. This paper presents both testing methodology as well as clear indication of the behaviour of three woody biomass pellets on exposure to high relative humidity