5,047 research outputs found
Active cooling from the sixties to NASP
Vehicles, such as the X-15 or National Aero-Space Plane, traveling at hypersonic speeds through the earth's atmosphere experience aerodynamic heating. The heating can be severe enough that a thermal protection system is required to limit the temperature of the vehicle structure. Although several categories of thermal protection systems are mentioned briefly, the majority of this paper describes convectively cooled structures for large areas. Convective cooling is a method of limiting structural temperatures by circulating a coolant through the vehicle structure. Efforts to develop convectively cooled structures during the past 30 years--from early engine structures, which were intended to be tested on the X-15, to structural--are described. Many of the lessons learned from these research efforts are presented
Bridging the gap: rewritable electronics using real-time light-induced dielectrophoresis on lithium niobate
In the context of micro-electronics, the real-time manipulation and placement of components using optics alone promises a route towards increasingly dynamic systems, where the geometry and function of the device is not fixed at the point of fabrication. Here, we demonstrate physically reconfigurable circuitry through light-induced dielectrophoresis on lithium niobate. Using virtual electrodes, patterned by light, to trap, move, and chain individual micro-solder-beads in real-time via dielectrophoresis, we demonstrate rewritable electrical contacts which can make electrical connections between surface-bound components. The completed micro-solder-bead bridges were found to have relatively low resistances that were not solely dominated by the number of interfaces, or the number of discrete beads, in the connection. Significantly, these connections are formed without any melting/fusing of the beads, a key feature of this technique that enables reconfigurability. Requiring only a low-power (~3.5 mW) laser source to activate, and without the need for external power supply or signal generation, the all-optical simplicity of virtual-electrodes may prove significant for the future development of reconfigurable electronic systems
Substance Use and Depression Symptomatology: Measurement Invariance of the Beck Depression Inventory (BDI-II) among Non-Users and Frequent-Users of Alcohol, Nicotine and Cannabis
Depression is a highly heterogeneous condition, and identifying how symptoms present in various groups may greatly increase our understanding of its etiology. Importantly, Major Depressive Disorder is strongly linked with Substance Use Disorders, which may ameliorate or exacerbate specific depression symptoms. It is therefore quite plausible that depression may present with different symptom profiles depending on an individual’s substance use status. Given these observations, it is important to examine the underlying construct of depression in groups of substance users compared to non-users. In this study we use a non-clinical sample to examine the measurement structure of the Beck Depression Inventory (BDI-II) in non-users and frequent-users of various substances. Specifically, measurement invariance was examined across those who do vs. do not use alcohol, nicotine, and cannabis. Results indicate strict factorial invariance across non-users and frequent-users of alcohol and cannabis, and metric invariance across non-users and frequent-users of nicotine. This implies that the factor structure of the BDI-II is similar across all substance use groups
Seeing Young Fathers in a Different Way: Editorial
I think it's absolutely outrageous that so many young men in our society feel they can go out, get women pregnant, allow them to have children, make them bring them up by themselves, often on benefits, and then just disappear. It is utterly shocking and I hope ... the ministers will get hold of some of these feckless fathers, drag them off, make them work, put them in chains if necessary.... (David Davies MP, 12 November 2013, House of Commons; Cornack, 2013
Supporting young fathers: the promise, potential and perils of statutory service provision
This article provides a case study of the challenges faced by one local authority in supporting young fathers, in a context of changing models of service provision, resource constraints and professional training needs. Developments in service provision are tracked over a decade, starting with a mentoring service set up under New Labour's 10-year Teenage Pregnancy Strategy, and considering how this has been refashioned under new models of service provision. The article was developed in close consultation with local authority service providers and draws on both professional accounts and the perspectives of young fathers as clients of the service. Overall, the article contributes to debates around the relative strengths of mainstream and specialist support for young fathers, and suggests the value of specialist support within mainstream provision
Survey Research Center at IUPUI
poster abstractThis poster will describe the different ways in which the Survey Research Center at IUPUI (SRC) can help serve IUPUI faculty, staff and students as well as organizations not affiliated with the campus with research design, data collection, data management and data analyses. The poster will use recent surveys for which SRC has been a leader in designing, collecting and analyzing data to show the possibilities for collaboration to show the possibilities of collaboration within and outside the IUPUI community. SRC, a research center within the Institute for Research on Social Issues (IRSI) within the School of Liberal Arts, is an interdisciplinary survey research center that provides services to a wide variety of private, nonprofit, and governmental organizations. The center also serves the entire IUPUI campus by conducting research for faculty members, students, and various university departments. The SRC is equipped with call stations (for telephone interviewing) and is equipped to conduct face-toface, web and mail surveys depending on research design needs
Spatially selecting single cell for lysis using light induced electric fields
An optoelectronic tweezing (OET) device, within an integrated microfluidic channel, is used to precisely select single cells for lysis among dense populations. Cells to be lysed are exposed to higher electrical fields than their neighbours by illuminating a photoconductive film underneath them. Using beam spot sizes as low as 2.5 μm, 100% lysis efficiency is reached in <1 min allowing the targeted lysis of cells
Use of optoelectronic tweezers in manufacturing – accurate solder bead positioning
In this work, we analyze the use of optoelectronic tweezers (OETs) to manipulate 45 μm diameter Sn62Pb36Ag2 solder beads with light-induced dielectrophoresis force and we demonstrate high positioning accuracy. It was found that the positional deviation of the solder beads increases with the increase of the trap size. To clarify the underlying mechanism, simulations based on the integration of the Maxwell stress tensor were used to study the force profiles of OET traps with different sizes. It was found that the solder beads felt a 0.1 nN static friction or stiction force due to electrical forces pulling them towards the surface and that this force is not dependent on the size of the trap. The stiction limits the positioning accuracy; however, we show that by choosing a trap that is just larger than the solder bead sub-micron positional accuracy can be achieved
High performance in healthcare priority setting and resource allocation: a literature- and case study-based framework in the Canadian context
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