1,705 research outputs found
Evaluation of high specific-heat ceramic for regenerator use at temperatures between 2-30 K
Specific heat, thermal conductivity (both in the range 2-30 K), and microhardness data were measured on the ceramics labelled LS-8, LS-8A, and LS-8A doped with CsI, SnCl2, and AgCl. A work hardened sample of LS-8A was also studied in an effort to determine the feasibility of using these types of LS-8 materials to replace Pb spheres in the regenerator of the JPL cryocooler. The LS-8A materials are all more than an order of magnitude harder than Pb, and the dopants do not significantly improve the hardness. However, the SnCl2 dopant has a remarkable effect in improving the specific heat and thermal conductivity of LS-8A. The SnCl2 doping level which maximized the regenerator enthalpy change in going from an unloaded to a loaded condition was found to be 0.2 percent SnCl2 in LS-8A. It was also found that the enthalpy change for a regenerator employing the LS-8A material is more than three times larger than for the Pb spheres case. The use of rods, rather than spheres, of optimally doped LS-8A in regenerators is discussed
Preparation of pure lithium hexafluoroarsenate Final report
Preparation and analysis of high purity lithium hexafluoroarsenat
Gimbaled-shoulder friction stir welding tool
A gimbaled-shoulder friction stir welding tool includes a pin and first and second annular shoulders coupled to the pin. At least one of the annular shoulders is coupled to the pin for gimbaled motion with respect thereto as the tool is rotated by a friction stir welding apparatus
Ireland's international trade and transport connections. ESRI WP573, October 2017
This paper looks at the transport patterns of Irish international trade. In
particular, we examine how trade flows in weight differ from those measured by value
and the implications that this has for transport mode and cost. In an environment of
uncertainty relating to the impact of Brexit, the much larger share of the UK in total Irish
export volumes (tonnages) compared to values signals possible significant impacts on
transport and also on costs if increased customs procedures are introduced. We also look
at the use of the UK as a land-bridge for Irish trade further afield, finding that a
considerable percentage of Irish trade uses this transport option
Long noncoding RNAs in liver cancer: what we know in 2014.
INTRODUCTION: Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer with an estimated over half a million new cases diagnosed annually. Due to the difficulty in early diagnosis and lack of effective treatment options, HCC is currently ranked as the second highest neoplastic-related mortality in the world, with an extremely low 5-year survival rate of between 6 and 11%. Long noncoding RNAs (lncRNAs), are genes lacking protein coding ability, have recently emerged as pivotal participants in biological processes, often dysregulated in a range of cancers, including HCC.
AREAS COVERED: In this review, we highlight the recent findings of lncRNAs in HCC pathogenesis, with particular attention on epigenetic events. In silico analysis was utilized to emphasize intrinsic linkages within the ncRNA families associated with hepatocarcinogenesis.
EXPERT OPINION: While our understanding of lncRNAs in the onset and progression of HCC is still in its infancy, there is no doubt that understanding the activities of ncRNAs will certainly secure strong biomarkers and improve treatment options for HCC patients
Thematic Analysis of Teacher Instructional Practices and Student Responses in Middle School Classrooms with Problem-Based Learning Environment
Problem-based learning (PBL) environment is a student-centered instructional method based on the use of ill-structured problems as a stimulus for collaborative learning. This study tried to gain an understanding of teachersΓÇÖ instructional practices and studentsΓÇÖ responses to such practices in middle school classrooms with PBL environment through qualitative analyses. A hybrid approach of inductive and deductive thematic analyses was employed and applied to field notes and transcripts of video observations of four PBL classrooms. To do so, a codebook was created based on the descriptions of roles of teachers and students in PBL classrooms in literature, and was then applied to inductive codes that emerged from the data. This study identified a number of specific instructional practices of teachers, as well as responses that students might engage in during PBL instructions. Being able to articulate these roles is an important step in helping new PBL teachers learn to facilitate student-centered classrooms
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Small, Inexpensive Combined NOx and O2 Sensor
It has been successfully demonstrated in this program that a zirconia multilayer structure with rhodium-based porous electrodes performs well as an amperometric NO{sub x} sensor. The sensitivity of the sensor bodies operating at 650 to 700 C is large, with demonstrated current outputs of 14 mA at 500 ppm NO{sub x} from sensors with 30 layers. The sensor bodies are small (4.5 x 4.2 x 3.1 mm), rugged, and inexpensive. It is projected the sensor bodies will cost 10 in production. This program has built on another successful development program for an oxygen sensor based on the same principles and sponsored by DOE. This oxygen sensor is not sensitive to NO{sub x}. A significant technical hurdle has been identified and solved. It was found that the 100% Rh electrodes oxidize rapidly at the preferred operating temperatures of 650-700 C, and this oxidation is accompanied by a volume change which delaminates the sensors. The problem was solved by using alloys of Rh and Pt. It was found that a 10%/90% Rh/Pt alloy dropped the oxidation rate of the electrodes by orders of magnitude without degrading the NO{sub x} sensitivity of the sensors, allowing long-term stable operation at the preferred operating temperatures. Degradation in the sensor output caused by temperature cycling was identified as a change in resistance at the junction between the sensor body and the external leads attached to the sensor body. The degradation was eliminated by providing strong mechanical anchors for the wire and processing the junctions to obtain good electrical bonds. The NO{sub x} sensors also detect oxygen and therefore the fully-packaged sensor needs to be enclosed with an oxygen sensor in a small, heated zirconia chamber exposed to test gas through a diffusion plug which limits the flow of gas from the outside. Oxygen is pumped from the interior of the chamber to lower the oxygen content and the combination of measurements from the NO{sub x} and oxygen sensors yields the NO{sub x} content of the gas. Two types of electronic control units were designed and built. One control unit provides independent constant voltages to the NOx and oxygen sensors and reads the current from them (that is, detects the amount of test gas present). The second controller holds the fully-assembled sensor at the desired operating temperature and controllably pumps excess oxygen from the test chamber. While the development of the sensor body was a complete success, the development of the packaging was only partially successful. All of the basic principles were demonstrated, but the packaging was too complex to optimize the operation within the resources of the program. Thus, no fully-assembled sensors were sent to outside labs for testing of cross-sensitivities, response times, etc. Near the end of the program, Sensata Technologies of Attleboro, MA tested the sensor bodies and confirmed the CeramPhysics measurements as indicated in the following attached letter. Sensata was in the process of designing their own packaging for the sensor and performing cross-sensitivity tests when they stopped all sensor development work due to the automotive industry downturn. Recently Ceramatec Inc. of Salt Lake City has expressed an interest in testing the sensor, and other licensing opportunities are being pursued
Stakeholder Participation in the Environmental Clean Up of Radioactive Wastes in the United Kingdom, Japan and United States
We review our program of research on stakeholder participation with environmental cleanup from radioactive wastes in the United States, Japan and United Kingdom (e.g., [21,26,27,66]). Citizen participation programs in all three countries are at different stages: mature in the US, starting in Japan, and becoming operational in the UK. The US issue at the Savannah River Site (SRS) in South Carolina (SC) had been focused on citizens encouraging Federal (Department of Energy, or DOE; Environmental Protection Agency, or EPA) and State (SC's Department of Health and Environmental Compliance, or DHEC) agencies to aggressively pursue "Plug-in-RODs" at SRS to reduce the paperwork involved in order to accelerate the closure of seepage basins at SRS. The issue in Japan is an effective division of labor among participants and the representation of different perspectives in the deliberation process, including citizens. The UK issue is centered around effective citizen participation with the UK's Nuclear Decommissioning Authority (NDA). Looking at our program of research, our hope is that a review of the programs in these three countries may improve citizen advisory programs
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