Data compression applied to HHVT

A task order was written by the High Resolution, High Frame Rate Video Technology (HHVT) project engineers to study data compression techniques that could be applied to the HHVT system. Specifically, the goals of the HHVT data compression study are to accomplish the following: (1) Determine the downlink capabilities of the Space Shuttle and Space Station Freedom to support HHVT data (i.e., determine the maximum data rates and link availability); (2) Determine current and projected capabilities of high speed storage media to support HHVT data by determining their maximum data acquisition/transmission rates and volumes; (3) Identify which experiment in the HHVT Users' Requirement data base need data compression, based on the experiments' imaging requirements; (4) Select the best data compression technique for each of these users by identifying a technique that provides compression but minimizes distortion; and (5) Investigate state-of-the-art technologies for possible implementation of selected data compression techniques. Data compression will be needed because of the high data rates and larger volumes of data that will result from the use of digitized video onboard the Space Shuttle and Space Station Freedom

Session 1-4-B: Gambling and Marijuana Use in the Netherlands: Is Legalization the Best Tool for Dealing With Naughty Habits?

In 1976, the Netherlands embraced two policy initiatives which encompassed similar objectives. The policies sought to control “undesired substances” via the process of legalization. One legalization process involved casino gambling. The policies have sometimes led to desired results (the right road), while at other times they have led to undesirable results (the wrong road). Now in 2013, without an observable crossroad or even fork in the road, The Netherlands is poised to deviate from a right road to travel down a wrong road by placing rather severe restrictions upon the operations of “Coffee Houses” which have been “serving” customers measured amounts of cannabis. This paper examines the experiences with the policies over the past 36 years, and speculates upon the effects of the new policies for the “Coffee Houses.” We ask if what is happening is “kinda” like an old Crystal Gayle song from the 1970s: “Down that Wrong Road Again”

Three-Dimensional Field Solutions for Multi-Pole Cylindrical Halbach Arrays in an Axial Orientation

This article presents three-dimensional B field solutions for the cylindrical Halbach array in an axial orientation. This arrangement has applications in the design of axial motors and passive axial magnetic bearings and couplers. The analytical model described here assumes ideal magnets with fixed and uniform magnetization. The field component functions are expressed as sums of 2-D definite integrals that are easily computed by a number of mathematical analysis software packages. The analysis is verified with sample calculations and the results are compared to equivalent results from traditional finite-element analysis (FEA). The field solutions are then approximated for use in flux linkage and induced EMF calculations in nearby stator windings by expressing the field variance with angular displacement as pure sinusoidal function whose amplitude depends on radial and axial position. The primary advantage of numerical implementation of the analytical approach presented in the article is that it lends itself more readily to parametric analysis and design tradeoffs than traditional FEA models

Evaluating the accuracy of size perception in real and virtual environments

ManuscriptAccurate perception of the size of 3D objects depicted on 2D desktop displays is important for many applications. Whether users perceive objects depicted on a display to be the same size as comparable real world objects is not well understood. We propose using affordances judgments as a way of measuring the perceived size of objects depicted in desktop virtual environments and the real world. The methodology involves indicating whether or not a particular action can be performed in a given environment, making it a flexible measure that can be used across different display technologies. In two studies, we test users' perceptions of size by asking them to make affordance judgments in both the real world and a geometrically matched desktop virtual environment. In the first study, users judge whether they can grasp an object and in the second study, they judge whether they can fit their hand through an opening. In both experiments we show that users perceive the size of objects in the desktop virtual environment to be smaller than in the real world

Concise Review: Plasma and Nuclear Membranes Convey Mechanical Information to Regulate Mesenchymal Stem Cell Lineage

Numerous factors including chemical, hormonal, spatial, and physical cues determine stem cell fate. While the regulation of stem cell differentiation by soluble factors is well-characterized, the role of mechanical force in the determination of lineage fate is just beginning to be understood. Investigation of the role of force on cell function has largely focused on “outside-in” signaling, initiated at the plasma membrane. When interfaced with the extracellular matrix, the cell uses integral membrane proteins, such as those found in focal adhesion complexes to translate force into biochemical signals. Akin to these outside-in connections, the internal cytoskeleton is physically linked to the nucleus, via proteins that span the nuclear membrane. Although structurally and biochemically distinct, these two forms of mechanical coupling influence stem cell lineage fate and, when disrupted, often lead to disease. Here we provide an overview of how mechanical coupling occurs at the plasma and nuclear membranes. We also discuss the role of force on stem cell differentiation, with focus on the biochemical signals generated at the cell membrane and the nucleus, and how those signals influence various diseases. While the interaction of stem cells with their physical environment and how they respond to force is complex, an understanding of the mechanical regulation of these cells is critical in the design of novel therapeutics to combat diseases associated with aging, cancer, and osteoporosis

An Investigation of Ionic Wind Propulsion

A corona discharge device generates an ionic wind and thrust, when a high voltage corona discharge is struck between sharply pointed electrodes and larger radius ground electrodes. The objective of this study was to examine whether this thrust could be scaled to values of interest for aircraft propulsion. An initial experiment showed that the thrust observed did equal the thrust of the ionic wind. Different types of high voltage electrodes were tried, including wires, knife-edges, and arrays of pins. A pin array was found to be optimum. Parametric experiments, and theory, showed that the thrust per unit power could be raised from early values of 5 N/kW to values approaching 50 N/kW, but only by lowering the thrust produced, and raising the voltage applied. In addition to using DC voltage, pulsed excitation, with and without a DC bias, was examined. The results were inconclusive as to whether this was advantageous. It was concluded that the use of a corona discharge for aircraft propulsion did not seem very practical

Sulfide mineralization in deep-water marine sediments related to methane transport, methane consumption, and methane gas hydrates

Patterns of sulfide sulfur concentration and sulfur isotopic composition (d34 S) are perhaps related to upward methane transport, especially in sediments underlain by methane gas hydrate deposits. Increased methane delivery augments the effect of anaerobic methane oxidation (AMO) occurring at the sulfate-methane interface (SMI). Sulfate and methane co-consumption results in production of dissolved sulfide at the interface that is eventually sequestered within sulfide minerals (elemental sulfur, iron monosulfide, pyrite). We examine the sediments of two piston cores collected over the Blake Ridge gas hydrate deposits (offshore southeastern United States) by extracting total sedimentary sulfide using chromium reduction. We use an improved titration procedure to assay for sulfide sulfur concentration that involves addition of an excess amount of potassium iodate/potassium iodide (KIO3/KI) solution in order to completely oxidize dissolved sulfide to elemental sulfur. The remaining iodine ions are then back-titrated with sodium thiosulfate solution, avoiding leakage of hydrogen sulfide gas, thus increasing measurement accuracy. Our results show that authigenic sulfide sulfur generally increases in concentration downcore from ~0.05 to peak concentrations approaching 0.4 weight per cent sulfur (dry weight). These results are consistent with localized sulfide production at the SMI and rapid sulfide mineral formation there. We will further test the hypothesis by examining d34 S values of authigenic sulfide minerals, expecting to see enrichments in d34 S near the interface. Discrete horizons showing sulfide mineralization with 34S enrichments potentially record periods of increased methane flux, highlighting an increased role for AMO as a biogeochemical process and perhaps identifying existence of underlying gas hydrates

Sulfide mineralization in deep-water marine sediments related to methane transport, methane consumption, and methane gas hydrates

Patterns of sulfide sulfur concentration and sulfur isotopic composition (d34 S) are perhaps related to upward methane transport, especially in sediments underlain by methane gas hydrate deposits. Increased methane delivery augments the effect of anaerobic methane oxidation (AMO) occurring at the sulfate-methane interface (SMI). Sulfate and methane co-consumption results in production of dissolved sulfide at the interface that is eventually sequestered within sulfide minerals (elemental sulfur, iron monosulfide, pyrite). We examine the sediments of two piston cores collected over the Blake Ridge gas hydrate deposits (offshore southeastern United States) by extracting total sedimentary sulfide using chromium reduction. We use an improved titration procedure to assay for sulfide sulfur concentration that involves addition of an excess amount of potassium iodate/potassium iodide (KIO3/KI) solution in order to completely oxidize dissolved sulfide to elemental sulfur. The remaining iodine ions are then back-titrated with sodium thiosulfate solution, avoiding leakage of hydrogen sulfide gas, thus increasing measurement accuracy. Our results show that authigenic sulfide sulfur generally increases in concentration downcore from ~0.05 to peak concentrations approaching 0.4 weight per cent sulfur (dry weight). These results are consistent with localized sulfide production at the SMI and rapid sulfide mineral formation there. We will further test the hypothesis by examining d34 S values of authigenic sulfide minerals, expecting to see enrichments in d34 S near the interface. Discrete horizons showing sulfide mineralization with 34S enrichments potentially record periods of increased methane flux, highlighting an increased role for AMO as a biogeochemical process and perhaps identifying existence of underlying gas hydrates

Sulfide mineralization in deep-water marine sediments related to methane transport, methane consumption, and methane gas hydrates

Patterns of sulfide sulfur concentration and sulfur isotopic composition (d34S) are perhaps related to upward methane transport, especially in sediments underlain by methane gas hydrate deposits. Increased methane delivery augments the affect of anaerobic methane oxidation (AMO) occurring at the sulfate-methane interface (SMI). Sulfate and methane co-consumption results in production of dissolved sulfide at the interface that is eventually sequestered within sulfide minerals (elemental sulfur, iron monosulfide, pyrite). We examine the sediments of two piston cores collected over the Blake Ridge gas hydrate deposits (offshore southeastern North America) by extracting total sedimentary sulfide using chromium reduction. We use an improved titration procedure to assay for sulfide sulfur concentration that involves addition of an excess amount of potassium iodate/potassium iodide (KIO3/KI) solution in order to completely oxidize dissolved sulfide to elemental sulfur. The remaining iodine ions are then back-titrated with sodium thiosulfate solution, avoiding leakage of hydrogen sulfide gas, thus increasing measurement accuracy. Our results show that authigenic sulfide sulfur generally increases in concentration downcore from ~0.05 to peak concentrations approaching 0.4 weight per cent sulfur. These results are consistent with localized sulfide production at the SMI and rapid sulfide mineral formation there. We will further test the hypothesis by examining d34S values of authigenic sulfide minerals, expecting to see enrichments in d34S near the interface. Discrete horizons showing sulfide mineralization with 34S enrichments potentially record periods of increased methane flux, highlighting an increased role for AMO as a biogeochemical process and perhaps identifying existence of underlying gas hydrates

Relative Concentration of Solid-phase Sulfide Species in Marine Sediments Overlying Gas Hydrate Deposits: Recognition of the Role of Anaerobic Methane Oxidation in Authigenic Sulfide Formation

Sulfide mineralization in marine sediments occurs when dissolved sulfide, produced by sulfate reduction processes, combines with dissolved iron to form iron sulfide minerals. Sulfide can be produced by oxidation of organic matter or by anaerobic methane oxidation (AMO), which involves the co-consumption of sulfate and methane. The latter process seems especially important within gas hydrate terrains like that of theBlakeRidge(offshore southeasternUnited States), where appreciable amounts of methane diffuse upward to the base of the sulfate reduction zone, or sulfate-methane interface (SMI). We examine the sediments of two piston cores collected over the Blake Ridge gas hydrate deposits by sequentially extracting the different phases of sulfide minerals: elemental sulfur (So), iron monosulfides (FeS), “young” pyrite, and “old” pyrite. So and FeS are extracted using dichloromethane and hot stannous chloride solution, respectively. Youthful pyrite is extracted using cold chromic chloride solution, whereas older pyrite is extracted with hot chromic chloride. We use an improved titration procedure to assay for sulfide-sulfur concentration that involves iodometry and back-titration with sodium thiosulfate solution. Our results show concentrations of elemental sulfur and iron monosulfides vary from ~0.02-0.07 weight percent sulfur with no systematic trends with depth. Young pyrite generally increases in concentration downcore from ~0.04 to peak concentrations approaching 0.17 weight percent sulfur at or near the SMI. Old pyrite concentrations are usually less than 0.05 weight percent sulfur, generally less than young pyrite concentration. Assuming that our procedure actually separates different phases of sulfide sulfur, these results seem consistent with localized sulfide production at the SMI where we expect to see an increased fraction of the young pyrite phase as a result of rapid sulfide mineral formation due to AMO occurring there. We can test this interpretation by determining the sulfur isotopic composition of each sulfide phase. We expect to see enrichments of 34S in the youthful pyrite fraction near the SMI