Solid Freeform Fabrication of Artificial Human Teeth

In this paper, we describe a solid freeform fabrication procedure for human dental restoration via porcelain slurry micro-extrusion. Based on submicron-sized dental porcelain powder obtained via ball milling process, a porcelain slurry formulation has been developed. The formulation developed allows the porcelain slurry to show a pseudoplastic behavior and moderate viscosity, which permits the slurry to re-shape to form a near rectangular cross section. A well-controlled cross-section geometry of the extrudate is important for micro-extrusion to obtain uniform 2-D planes and for the addition of the sequential layers to form a 3-D object. Human teeth are restored by this method directly from CAD digital models. After sintering, shrinkage of the artificial teeth is uniform in all directions. Microstructure of the sintered teeth is identical to that made via traditional dental restoration processes.Mechanical Engineerin

Supplier development practice: arising the problems of upstream delivery for a food distribution SME in the UK

The paper aims to emphasize on the impacts of the supplier development on reducing the defects in supplier quality for a food distribution small–medium sized enterprise (SME). An empirical study was conducted to measure the performance of the suppliers in three different key performance indicators of the outsourcing and supplier’s performance to arise the existing problems via information exchange, data collection and data analysis. It was found that supplier development through data and information exchange and better communication by any food distribution SME raises the problems more promptly. This can dramatically change the supplier’s behavior to improve the quality of the supplier’s service and products. It is suggested that more research is required to raise other key performance indicators and their related problems and to develop more improvement practices. Six sigma methodologies could be the potential good practices to be focused in future research studies. Supplier performance measurement, which encompasses data exchange and data collection, develops the systematic flow of information, which potentially improves the flow of goods and the whole food supply chain to address the final consumer satisfaction. The research took a novel approach in adopting some transport related key performance indicators of the food supply to the food distribution and retailing sector, which is almost a new approach in food industry

The early early type: discovery of a passive galaxy at z=3

We present the discovery of a massive, quiescent galaxy at z=2.99. We have obtained a HST/WFC3 spectrum of this object and measured its redshift from the detection of a deep 4000A break consistent with an old population and a high metallicity. By stellar population modeling of both its grism spectrum and broad-band photometry, we derive an age of ~0.7 Gyr, implying a formation redshift of z>4, and a mass >10^11 Msun. Although this passive galaxy is the most distant confirmed so far, we find that it is slightly less compact than other z>2 early-types of similar mass, being overall more analogous to those z~1.6 field early-type galaxies. The discovery of this object shows that early-type galaxies are detectable to at least z=3 and suggests that the diversity of structural properties found in z=1.4-2 ellipticals to earlier epochs could have its origin in a variety of formation histories among their progenitors.Comment: 6 pages, 4 figures, 1 table. Accepted for publication in The Astrophysical Journal Letter

Quantifying the relationship between the power delivery network and architectural policies in a 3D-stacked memory device

pre-printMany of the pins on a modern chip are used for power delivery. If fewer pins were used to supply the same current, the wires and pins used for power delivery would have to carry larger currents over longer distances. This results in an "IR-drop" problem, where some of the voltage is dropped across the long resistive wires making up the power delivery network, and the eventual circuits experience fluctuations in their supplied voltage. The same problem also manifests if the pin count is the same, but the current draw is higher. IR-drop can be especially problematic in 3D DRAM devices because (i) low cost (few pins and TSVs) is a high priority, (ii) 3D-stacking increases current draw within the package without providing proportionate room for more pins, and (iii) TSVs add to the resistance of the power delivery net-work. This paper is the first to characterize the relationship be- tween the power delivery network and the maximum sup ported activity in a 3D-stacked DRAM memory device. The design of the power delivery network determines if some banks can handle less activity than others. It also deter-mines the combinations of bank activities that are permissible. Both of these attributes can feed into architectural policies. For example, if some banks can handle more activities than others, the architecture benefits by placing data from high-priority threads or data from frequently accessed pages into those banks. The memory controller can also derive higher performance if it schedules requests to specific combinations of banks that do not violate the IR-drop constraint

Doctor of Philosophy in Computing

dissertationThe demand for main memory capacity has been increasing for many years and will continue to do so. In the past, Dynamic Random Access Memory (DRAM) process scaling has enabled this increase in memory capacity. Along with continued DRAM scaling, the emergence of new technologies like 3D-stacking, buffered Dual Inline Memory Modules (DIMMs), and crosspoint nonvolatile memory promise to continue this trend in the years ahead. However, these technologies will bring with them their own gamut of problems. In this dissertation, I look at the problems facing these technologies from a current delivery perspective. 3D-stacking increases memory capacity available per package, but the increased current requirement means that more pins on the package have to be now dedicated to provide Vdd/Vss, hence increasing cost. At the system level, using buffered DIMMs to increase the number of DRAM ranks increases the peak current requirements of the system if all the DRAM chips in the system are Refreshed simultaneously. Crosspoint memories promise to greatly increase bit densities but have long read latencies because of sneak currents in the cross-bar. In this dissertation, I provide architectural solutions to each of these problems. We observe that smart data placement by the architecture and the Operating System (OS) is a vital ingredient in all of these solutions. We thereby mitigate major bottlenecks in these technologies, hence enabling higher memory densities

CDFIs and Online Business Lending: A Review of Recent Progress, Challenges, and Opportunities

The report, authored by Jack Northrup, Eric Hangen, and Michael Swack, looks at some of the issues CDFIs face as the fintech industry (technology companies involved in lending) grows and begins to target markets served by CDFIs