Step-Up Converter Interfaces for Magnetron Power Supply

Fine particulate matter like carbon soot harms the respiratory system. One approach to reducing soot pollution is microwave-assisted soot oxidation. The magnetron, which generates microwave energy requires a high-voltage gain converter. In this thesis, a DC/DC converter is proposed to supply the two voltages required by a magnetron by utilizing dual resonant circuit modules. By combining the switches of the step-up resonant stage with a bridgeless power factor correction (PFC) stage, an AC/DC topology is proposed. The proposed AC/DC topology allows for a high power factor (PF) and reduced input conduction losses. The converter utilizes a parallel CL resonant circuit with voltage doubler output to achieve a high-voltage gain, and an LLC resonant circuit to provide the step-down. The circuit is then verified through PSIM with a peak of 1.8kW. A proof-of-concept hardware test with AC input testing step-up 822V and step-down 1.3V outputs simultaneously with a 0.96PF is performed

National security, Islamophobia, and religious freedom in the U.S.

A central argument in Hurd’s (2015) Beyond Religious Freedom is that the religious freedom policy framework pursued by the United States not only entrenches lines of division between religious faiths, but also is constructive of those very divisions. Where foreign and domestic policies purport to promote tolerance and respectful pluralism in the name of religious freedom, Hurd (2015, 41) contends they instead create ‘new forms of social friction defined by religious difference.’ Utilizing Hurd’s (2015) categories of Official, Governed, and Lived religion I examine Islamophobia and the racialization of Muslims in the United States and demonstrate how over-identification with religious groups can exacerbate social tensions; how the ‘agenda of surveillance’ (Hurd 2015) disproportionately targets Muslims in the United States; and argue that recourse to law and policy alone in response to anti-Muslim discrimination is unlikely to transform social attitudes towards Muslims. Finally, I utilize a contemporary reworking of Adam Smith’s sympathetic imagination and radical democratic theory to propose an alternative pathway towards dissolving the pejorative ascription of difference to religiously othered individuals

A parameterization of Greenland's tip jets suitable for ocean or coupled climate models

Greenland's tip jets are low-level, high wind speed jets forced by an interaction of the synoptic-scale atmospheric flow and the steep, high orography of Greenland. These jets are thought to play an important role in both preconditioning for, and triggering of, open-ocean convection in the Irminger Sea. However, the relatively small spatial scale of the jets prevents their accurate representation in the relatively low resolution (~1 degree) atmospheric (re-)analyses which are typically used to force ocean general circulation models (e.g. ECMWF ERA-40 and NCEP reanalyses, or products based on these). Here we present a method of ‘bogussing’ Greenland's tip jets into such surface wind fields and thus, via bulk flux formulae, into the air-sea turbulent flux fields. In this way the full impact of these mesoscale tip jets can be incorporated in any ocean general circulation model of sufficient resolution. The tip jet parameterization is relatively simple, making use of observed linear gradients in wind speed along and across the jet, but is shown to be accurate to a few m s-1 on average. The inclusion of tip jets results in a large local increase in both the heat and momentum fluxes. When applied to a 1-dimensional mixed-layer model this results in a deepening of the winter mixed-layer of over 300 m. The parameterization scheme only requires 10 meter wind speed and mean sea level pressure as input fields; thus it is also suitable for incorporation into a coupled atmosphere-ocean climate model at the coupling stage

Influence of the Icelandic Low latitude on the frequency of Greenland tip jet events : implications for Irminger Sea convection

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): C04020, doi:10.1029/2006JC003807.The occurrence of Greenland tip jet events has been reported as the dominant factor controlling the formation of intermediate water in the Irminger Sea. It has been suggested that the frequency of these events is correlated with the North Atlantic Oscillation. To examine this process in more detail, we separate the North Atlantic Oscillation into Icelandic Low and Azores High components and carry out a regression fit of the frequency of tip jet events between 1961 and 2005. Our findings suggest that the frequency of Greenland tip jet events is highly dependent on the latitude of the Icelandic Low and the 2-year time-lagged February Icelandic Low latitude, with R2 = 0.48. We find that the winds near the southern tip of Greenland are predominately westerly during years when the Iceland Low is located above 63°N latitude. These conditions also correspond to colder air temperatures in the Labrador and Irminger Seas, implying larger oceanic heat losses due to the Greenland tip jet events and hence stronger convective overturning in the Irminger Sea.R. Pickart gratefully acknowledges support by National Science Foundation grant OCE-0450658 for this research

Post-construction support and the sustainability of rural water projects in Ghana

Many rural community-managed water supply programs in developing countries have been characterized by poor performance. In response, governments and non-governmental organizations have organized two types of “post-construction support” for village water and sanitation committees. The first, “demand-driven” approach leaves it largely up to communities themselves to seek out repair and other support services and to pay for them when needed. The second is a more “supply-driven” approach – to provide unsolicited technical assistance, training, trouble-shooting, and even financial assistance to communities. We evaluate the effect of these types of post construction support on the technical sustainability of community water supplies in rural Ghana using data collected from 200 villages in Volta and Brong Ahafo

Diasporas and democratization in the post-communist world

If diaspora communities are socialized with democratic values in Western societies, they could be expected to be sympathetic to the democratization of their home countries. However, there is a high degree of variation in their behavior. Contrary to the predominant understanding in the literature that diasporas act in exclusively nationalist ways, this article argues that they do engage with the democratization of their home countries. Various challenges to the sovereignty of their homelands explain whether diasporas involve with procedural or liberal aspects of democratization. Drawing evidence from the activities of the Ukrainian, Serbian, Albanian and Armenian diasporas after the end of communism, I argue that unless diasporas are linked to home countries that enjoy both international legal and domestic sovereignty, they will involve only with procedural aspects of democratization. Diasporas filter international pressure to democratize post-communist societies by utilizing democratic procedures to advance unresolved nationalist goals

Post-Construction Support and Sustainability in Community-Managed Rural Water Supply

Executive Summary This volume reports the main findings from a multi-country research project that was designed to develop a better understanding of how rural water supply systems are performing in developing countries. We began the research in 2004 to investigate how the provision of support to communities after the construction of a rural water supply project affected project performance in the medium term. We collected information from households, village water committees, focus groups of village residents, system operators, and key informants in 400 rural communities in Bolivia, Ghana, and Peru; in total, we discussed community water supply issues with approximately 10,000 individuals in these communities. To our surprise, we found the great majority of the village water systems were performing well. Our findings on the factors influencing their sustainability will, we hope, be of use to policy makers, investors, and managers in rural water supply

Winter mixed layer development in the central Irminger Sea : the effect of strong, intermittent wind events

Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 541-565, doi:10.1175/2007JPO3678.1.The impact of the Greenland tip jet on the wintertime mixed layer of the southwest Irminger Sea is investigated using in situ moored profiler data and a variety of atmospheric datasets. The mixed layer was observed to reach 400 m in the spring of 2003 and 300 m in the spring of 2004. Both of these winters were mild and characterized by a low North Atlantic Oscillation (NAO) index. A typical tip jet event is associated with a low pressure system that is advected by upper-level steering currents into the region east of Cape Farewell and interacts with the high topography of southern Greenland. Heat flux time series for the mooring site were constructed that include the enhancing influence of the tip jet events. This was used to force a one-dimensional mixed layer model, which was able to reproduce the observed envelope of mixed layer deepening in both winters. The deeper mixed layer of the first winter was largely due to a higher number of robust tip jet events, which in turn was caused by the steering currents focusing more storms adjacent to southern Greenland. Application of the mixed layer model to the winter of 1994–95, a period characterized by a high-NAO index, resulted in convection exceeding 1700 m. This prediction is consistent with hydrographic data collected in summer 1995, supporting the notion that deep convection can occur in the Irminger Sea during strong winters.KV and RP were supported by National Science Foundation Grant OCE-0450658. GWKM was supported by the Canadian Foundation for Climate and Atmospheric Sciences. MHR was supported by the Nordic Council of Ministers (West-Nordic Ocean Climate)

Preterm Delivery Disrupts the Developmental Program of the Cerebellum

A rapid growth in human cerebellar development occurs in the third trimester, which is impeded by preterm delivery. The goal of this study was to characterize the impact of preterm delivery on the developmental program of the human cerebellum. Still born infants, which meant that all development up to that age had taken place in-utero, were age paired with preterm delivery infants, who had survived in an ex-utero environment, which meant that their development had also taken place outside the uterus. The two groups were assessed on quantitative measures that included molecular markers of granule neuron, purkinje neuron and bergmann glia differentiation, as well as the expression of the sonic hedgehog signaling pathway, that is important for cerebellar growth. We report that premature birth and development in an ex-utero environment leads to a significant decrease in the thickness and an increase in the packing density of the cells within the external granular layer and the inner granular layer well, as a reduction in the density of bergmann glial fibres. In addition, this also leads to a reduced expression of sonic hedgehog in the purkinje layer. We conclude that the developmental program of the cerebellum is specifically modified by events that follow preterm delivery

Fluoxetine Exerts Age-Dependent Effects on Behavior and Amygdala Neuroplasticity in the Rat

The selective serotonin reuptake inhibitor (SSRI) Prozac® (fluoxetine) is the only registered antidepressant to treat depression in children and adolescents. Yet, while the safety of SSRIs has been well established in adults, serotonin exerts neurotrophic actions in the developing brain and thereby may have harmful effects in adolescents. Here we treated adolescent and adult rats chronically with fluoxetine (12 mg/kg) at postnatal day (PND) 25 to 46 and from PND 67 to 88, respectively, and tested the animals 7–14 days after the last injection when (nor)fluoxetine in blood plasma had been washed out, as determined by HPLC. Plasma (nor)fluoxetine levels were also measured 5 hrs after the last fluoxetine injection, and matched clinical levels. Adolescent rats displayed increased behavioral despair in the forced swim test, which was not seen in adult fluoxetine treated rats. In addition, beneficial effects of fluoxetine on wakefulness as measured by electroencephalography in adults was not seen in adolescent rats, and age-dependent effects on the acoustic startle response and prepulse inhibition were observed. On the other hand, adolescent rats showed resilience to the anorexic effects of fluoxetine. Exploratory behavior in the open field test was not affected by fluoxetine treatment, but anxiety levels in the elevated plus maze test were increased in both adolescent and adult fluoxetine treated rats. Finally, in the amygdala, but not the dorsal raphe nucleus and medial prefrontal cortex, the number of PSA-NCAM (marker for synaptic remodeling) immunoreactive neurons was increased in adolescent rats, and decreased in adult rats, as a consequence of chronic fluoxetine treatment. No fluoxetine-induced changes in 5-HT1A receptor immunoreactivity were observed. In conclusion, we show that fluoxetine exerts both harmful and beneficial age-dependent effects on depressive behavior, body weight and wakefulness, which may relate, in part, to differential fluoxetine-induced neuroplasticity in the amygdala