Design and Experimentation of a Premixed Rotating Detonation Engine

Desire for a more efficient air breathing engine has shifted research attention to the Rotating Detonation Engine (RDE). Detonation is a more efficient combustion process than deflagration and provides a pressure gain. The RDE detonation cycle occurs in a compact volume to produce a high specific impulse engine. Computational fluid dynamic (CFD) models have predicted higher specific impulse and detonation wave speeds than has been seen in experimental RDE. The CFD models frequently assume premixed reactants and ignore inlet geometries to facilitate rapid computation. An experimental premixed RDE was sought to test if the premixed assumption in CFD was the root cause of the discrepancy between computational and experimental results. Design of a successful premixed RDE employed a feed system that simultaneously arrested flashback into the premixture while it fed the detonation. Flashback arresting feed designs were explored with single injector tests and validated with a fully premixed RDE. A relationship between arresting length and detonation feed requirements was derived and used to design a premixed RDE that fed premixture through feed slots that were 2.5 cm long and 0.5 mm high and operated on ethylene fuel and air oxidizer. The premixed RDE operated within a narrower region of equivalence ratio than a non-premixed RDE. Chemiluminescence video indicated that the premixed RDE experience combustion reactant-product mixing, and supports the theory that mixing delays are the root cause of slower wave speeds in experimental RDE. Time averaged chemiluminescence results indicate that RDE detonations to not complete the reaction within the detonation wave, and suggest that future CFD studies should assume unmixed reactants, model the full injection geometry, and include a comprehensive chemical mechanism

Comparative Analysis of a High Bypass Turbofan using a Pulsed Detonation Combustor

It has been proposed that the implementation of a pulsed detonation combustor in a high-bypass turbofan engine would result in an engine that is both more efficient and more reliable. The validity of the performance claims are evaluated based on a comparison between the baseline and hybrid turbofans. The hybrid pulsed detonation engine was modeled in the Numerical Propulsion Simulation System (NPSS) and shares a common architecture with the baseline turbofan model, except that the combustor of the baseline engine is replaced with a pulsed detonation combustor. Detonation effects are calculated using a closed form solution of the Chapman-Jouguet Mach number with a total energy correction applied. Cycle time is calculated to provide a reasonable estimate of frequency for the user input geometry, and the losses due unsteady flow are accounted for by applying pressure and temperature losses to the fluid. A parametric study was performed to evaluate the effects of these losses on net thrust and TSFC. There is a definite level of acceptable loss that if surpassed makes pulsed detonation combustion a good candidate for inclusion into a hybrid turbofan engine

Kinematic analysis of conically scanned environmental properties

A method for determining the velocity of features such as wind. The method preferably includes producing sensor signals and projecting the sensor signals sequentially along lines lying on the surface of a cone. The sensor signals may be in the form of lidar, radar or sonar for example. As the sensor signals are transmitted, the signals contact objects and are backscattered. The backscattered sensor signals are received to determine the location of objects as they pass through the transmission path. The speed and direction the object is moving may be calculated using the backscattered data. The data may be plotted in a two dimensional array with a scan angle on one axis and a scan time on the other axis. The prominent curves that appear in the plot may be analyzed to determine the speed and direction the object is traveling

Prenatal Attachment in Twin Pregnancy

Twin births are associated with several medical, healthcare, socio-emotional, psychological and developmental consequences for families. Parents generally describe twin pregnancies as physically and emotionally difficult. Moreover, compared to singleton pregnancies, twin pregnancies are reported to carry higher maternal as well as perinatal morbidity and mortality. The aim of this chapter is to review literature on twin pregnancy and to give a comprehensive framework about parents’ experience of expecting twins. An important issue related to the psychological adjustment during twin pregnancies is prenatal attachment. During pregnancy, mothers use to think about their child-to-be, and they start to create representation of themselves as mothers. Prenatal attachment in twin pregnancies may differ from that in singleton ones. During a twin pregnancy, the mother-to-be has to deal with an identification process with two children at the same time and have to create a mental space that allow her to make representation of both children. The monitoring of these pregnancies is important for the creation and the consolidation of these maternal representations: ultrasound examinations revealed the fetal gender that facilitates naming the unborn twins and thinking to them as individuals and this is particularly important in the case of complicated twin pregnancies

Using the Transformative Storytelling Technique to Generate Empowering Narratives for Informal Caregivers:Semistructured Interviews, Thematic Analysis, and Method Demonstration

Background: The transformative storytelling technique is an innovative top-down approach to narrative therapy that aims to provide building blocks for creating flourishing narratives for target groups or populations. This approach acts as a facilitator for implementing the human-centered design in developing digital self-help tools for larger samples or target groups.Objective: This study applied the transformative storytelling technique, as a new approach in mental health, to develop empowering audio narratives for informal caregivers.Methods: A narrative inquiry was conducted with 17 informal caregivers (16 women and 1 man) who completed a semistructured interview, “Caregiver Life Story,” acquiring information about the beginning of the role, rising action, and critical point of the role. The participants' ages ranged from 41 to 84 years, with all participants providing care for at least a 6-month period. This inquiry was guided by the transformative storytelling technique, and aimed to collect data relevant to creating fictional stories based on real-life themes.Results: Twenty-five overall themes were distinguished across three a priori-set categories, providing narrative building blocks for the informal caregiver life stories. The final empowering caregiver life story was created as an example for this study, demonstrating the application of the transformative storytelling technique in an informal care context.Conclusions: The creation of empowering stories for populations or target groups in mental health care requires a unified and guided approach that will follow clear guidelines and storytelling principles. The transformative storytelling technique is a first of its kind in the mental health context, representing an initial step in enabling and supporting the creation of meaningful stories and the development of relatable, but productive, narratives. Such narratives have the potential to serve across media and digital platforms for supporting and improving well-being, and potentially triggering self-change in the target group or population.</p

Cancer and Pregnancy: becoming parents after an oncological diagnosis in women

The issue of cancer and pregnancy will be increasingly topical giving the rising trend of women diagnosed with cancer during childbearing period. Although oncological progress has allowed women who receive cancer diagnosis before or during pregnancy to satisfy their desire for maternity and to carry on gestation, there is still few awareness. In this chapter we present our research project and results carry out to date. The aim is to better understand challenges of women who experience pregnancy after or during cancer compared with non-oncological sample. We focus on the impact of cancer in the construction of prenatal attachment and related psychological aspects. We study resilience considered as a protective factor in the construction of mother-fetus relationship. Then, we present the results of a qualitative study conducted in order to have a deeper understanding of the psychological dynamics that help women with cancer diagnosis to develop their maternal identity. We explore the topic of breastfeeding in women with cancer history, investigating how the feeding method is related to mother’s mood states. Finally, we present the results about the cortisol concentration measurement during pregnancy. Our results show how it is very important to give women with oncological diagnosis the adequate support during puerperium

An Italian Study

The literature provides some evidence that the use of violent video games increases the risk for young people to develop aggressive cognitions and even behaviors. We aimed to verify whether exposure to violent video games is linked to problems of aggression in a sample of Italian children. Four questionnaires were administered to 346 children between 7 and 14 years of age, attending primary and secondary schools in Northern Italy. Variables measured were externalization, quality of interpersonal relationships, aggression, quality of coping strategies, and parental stress. Participants who preferred violent games showed higher scores for externalization and aggression. The use of violent video games and age were linked to higher levels of aggression, coping strategies, and the habitual video game weekly consumption of participants. Our data confirm the role of violent video games as risk factors for problems of aggressive behavior and of externalization in childhood and early adolescence

Caring for twins during infancy: A systematic review of the literature on sleeping and feeding practices amongst parents of twins

Objective To better investigate how the parents of twins approach the care of their infants in terms of feeding and sleeping practices after birth by examining the sleeping and feeding behaviours of parents with twin babies. Methods Three electronic databases (PubMed, PsycINFO, and ScienceDirect) were searched, and studies published between 2006 and 2016 were included. The Preferred Reporting Item for Systematic Reviews and Meta-Analyses (Moher et al., 2015) was adopted. Key findings were extracted and synthesised. Results Fourteen studies were included (three focused on sleeping, seven focused on feeding, and four focused on sleeping but considered feeding to be a secondary issue). Conclusion Caring for twins presents unique challenges that require specific choices to be made. The parents of twins could benefit from additional and specially developed advice from health professionals for considering and implementing adequate sleep and feeding practices that reduce parental fatigue and stress, as well as promote parent-twin relationships

Managing Children’s Fears during the COVID-19 Pandemic: Strategies Adopted by Italian Caregivers

Background: Life-threatening events, such as the COVID-19 pandemic, may generate feelings of insecurity and fear in the affected population, particularly children. Parents’ ability to help children cope with negative emotions is essential during challenging periods. The current study aims to analyse the coping strategies adopted by Italian caregivers concerning their children’s fears about COVID-19. Method: An online survey was administered during the Italian lockdown to 649 parents of at least one child aged 5 to 17 years old. Respondents completed the survey for themselves and their children. In addition, a qualitative content analysis of the data from the open-ended question was conducted (N = 569; 87.9% women; MAge = 45 years). Results: Several themes were identified. Firstly, families’ primary approach was ‘communication and meaning-making’. Secondly, another essential strategy was ‘the importance of safe space’, enabled by keeping routine in place and creating a loving and caring environment. Thirdly, other factors relevant to managing children’s fears were ‘adaptation’, ‘religion’, ‘a positive attitude’, and ‘humour and hope’. Finally, the last two strategies significant and valuable for Italian families were ‘flexibility’ and ‘maintaining virtual contacts. Conclusion: During the pandemic COVID-19, parents may have used various strategies to protect their children from stress. Future research could investigate single parents’ coping strategies explicitly developed during the COVID-19 lockdown

Monochorionic twins and the early mother-infant relationship: an exploratory observational study of mother-infant interaction in the post-partum period

The extraordinary increase in twin rates and specifically monochorionic twin pregnancies represents a major public health issue due to the associated increased risks for the mother, the child and their relationship. The aim of the present study was to examine the quality of mothers’ behaviour during mother–infant interaction in the early postpartum period by comparing mothers of twins and mothers of singletons during face-to-face interaction with their infants. Demographic and clinical information was collected by trained research psychologists from the mothers’ and the childrens’ clinical records and from interviews with the mothers. At three months (corrected for prematurity), the interactions of the dyads (11 mother-twin infant dyads and 11 mother-singleton dyads) were filmed at participants’ homes in accordance with the procedure of the Global Rating Scales. Maternal behaviour during interactions was assessed and rated by two trained research psychologists. With regard to the mothers’ interaction with each twin, no differences were found between mothers’ scores in every GRS subscale, indicating that mothers did not interact differently with their twins. Comparisons between mothers of MC twins and mothers of singletons showed that the quality of maternal sensitive behaviour during the interactions were lower in mothers of twins (0.35) Mothers of twins were also more distant during interactions with their babies and more likely to experience depression symptoms than mothers of singletons (0.05). Future research should examine mother-infant relationships following twin birth with larger samples. Such research will be especially useful in evaluating the potential benefits of interventions to promote positive mother-infant interactions