196,406 research outputs found
Nondestructive evaluation of bone cement and bone cement/metal interface failure
No full textTo quantify the failure mechanisms related to the loosening of cemented hip jointreplacements, novel techniques, capable of monitoring, nondestructively, the initiation andprogression of failure during in vitro fatigue tests, were employed. Fatigue testing of modelcement and cement-stem test pieces was monitored using acoustic emission (AE) sensors. Oncedamage was detected, an ultrasonic imaging system was used to obtain an image of the damagesite and to measure the stiffness of the affected region. This method of examination provided adetailed insight into the internal crack propagation and delamination patterns. Initial workwas conducted on bulk cement specimens subjected to bending and tension. The second stageof the work examined a model stem-cement interface under tensile opening loading conditions.A novel ultrasonic technique was used to measure the bond quality at the cement-metalinterface. Progressive delamination was identified over time, and the AE technique was able toidentify critical areas of delamination before they could be identified conclusively byultrasonic imaging. The work has demonstrated the potential of the AE technique as a tool forthe preclinical assessment of total hip replacements
Non-destructive evaluation of cemented metallic implants for pre-clinical prediction of implant loosening
No full textEnergy assessment of hybrid heat pump systems as a retrofit measure in residential housing stock
No full textHybrid electric-gas heat pump systems are a possible retrofit option in older residential buildings. Older buildings can be challenging to retrofit and in this context hybrid systems can offer an intermediate route to decarbonisation of building heating energy demand. This is especially the case, where deep retrofit measures coupled with monovalent electric heat pump systems may not be feasible from an economic perspective. The aim of the current paper is to examine the suitability of a hybrid electric-gas heat pump system in comparison to electric heat pump systems as a retrofit measure for Irish housing stock and to benchmark both options against existing fossil fuel baseline systems. A detailed building energy model of a residential dwelling was developed and calibrated to within acceptable ASHRAE standards. An energy assessment was carried out which investigates each retrofit scenario. Key findings include: (i) both the all-electric and hybrid heat pump systems deliver primary energy savings compared to the fossil fuel baseline systems, (ii) hybrid systems attain higher primary energy savings compared to all-electric heat pump, where the hybrid system incorporates flexible delivery temperatures compared to a fixed delivery temperature tor the all-electric heat pump system
Technical and economic assessment of a hybrid heat pump system as an energy retrofit measure in a residential building
No full textAir to water electric heat pumps are one technological solution to achieve energy defossilisation goals for heating of residential building stock. Nevertheless, they may not necessarily be the only solution for all residential building stock. A case in point is where extensive fabric refurbishment is impracticable or where electric heat pumps are installed where low ambient temperatures prevail and/or high water delivery temperatures must be utilised. For such instances, hybrid (gas and electric) heat pumps offer an alternative option by facilitating fuel source switching between electricity and gas, when ambient temperatures are low or high water supply temperatures are required. In the current study, the effectiveness of an air-to-water electric heat pump and hybrid heat pump are examined for different building retrofit scenarios for a residential dwelling located in Ireland. This is achieved by means of a sensitivity study of a validated building simulation model, incorporating both heat pump systems, subject to different building retrofit scenarios. Relative to a conventional oil-fired boiler, for a deep building retrofit scenario, the hybrid and electric heat pumps achieve primary energy reduction of 128 kWh/m2/year (72%) and of 123 kWh/m2/year (70%), respectively. Considering the associated carbon footprints, the reductions were found to be 29.7 gCO2e/m2/year (74%) for the hybrid heat pump, and 27.6 gCO2e/m2/year (68%) for the electric heat pump. Finally, the deployment of either an electric heat pump or hybrid heat pump for deep building fabric retrofit achieves approximately half of the heating system capital cost return within 20 years
Linguistic Validation of the Sleep Disturbance Scale for Children (SDSC) in Iranian Children with Persian Language.
No full textDr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Forecast climate change impact on pore-water pressure regimes for the design and assessment of clay earthworks
No full textUnderstanding and mitigating the impact of climate change on the built environment is becoming increasingly important worldwide. Earthworks (embankments and cuttings) supporting road and rail transportation networks often have direct contact with the atmosphere and are therefore influenced by extreme weather events and seasonal weather patterns. Atmospheric wetting and drying alters pore-water pressures (PWP) within earthworks, potentially contributing to the deformation and failure of earthwork slopes. Consequently, it is essential to understand the influence of climate change on PWPs within earthwork slopes, to inform strategies for their design, assessment and maintenance. Extensive one-dimensional seepage analyses were carried out for typical railway embankments in the London area. The analyses showed that forecast hotter, drier summers will increase the water storage capacity of earthworks. This will lead to increased net infiltration in the winter months due to both a forecast increase in rainfall, and a longer time being required to saturate the soil pores and bring the water table back to the slope surface. Hence, despite the forecast increase in winter rainfall, this will not lead to higher design PWP regimes. The analyses were conducted for the London area, but the methodology and conceptual framework can be readily adapted for other locations
- …
