bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dialysis at a Crossroads
Authors: Parker Thomas , Hakim Raymond , Nissenson Allen R. , Steinman Theodore , Glassock Richard J. 
Published: December 2010

Summary
The ability to offer repetitive hemodialysis for treatment of chronic kidney failure has now reached its half-century anniversary. Although millions of patients have benefited from this life-extending procedure, current results in the United States have now stagnated with only small annual improvements in survival and continued high hospitalization rates. Recognition that this stagnation may be, at least in part, the result of inadequacies of current and prior paths utilized in dialysis treatment has led to the concept that dialysis therapy is at a crossroads and that new paths need to be articulated, explored, and applied. This article proposes some of these new paths and their rationale. Two elements of the new paths are emphasized: avoidance of indwelling catheters for vascular access and meticulous attention to control of extracellular volume and mitigation of left ventricular hypertrophy and fibrosis. It is postulated that progress in these two areas, along with continued attention to other elements embodied in the new and old paths, will unlock the stagnation in outcomes of dialysis therapy of end-stage kidney failure and allow it to realize its full potential of prolonging life and alleviating disability.
Mathematical Model of the Effective Properties of a Fiber Reinforced Composite with a Linearly Graded Transition Zone
Authors: Childers Carey F. 
Published: December 2010

Abstract
Tires are fabricated using single ply fiber reinforced composite materials, which consist of a set of aligned stiff fibers of steel material embedded in a softer matrix of rubber material. The main goal is to develop a mathematical model to determine the local stress and strain fields for this isotropic fiber and matrix separated by a linearly graded transition zone. This model will then yield expressions for the internal stress and strain fields surrounding a single fiber. The fields will be obtained when radial, axial, and shear loads are applied. The composite is then homogenized to determine its effective mechanical properties—elastic moduli, Poisson ratios, and shear moduli. The model allows for analysis of how composites interact in order to design composites which gain full advantage of their properties.
Use of Orthogonal Arrays for Efficient Evaluation of Geometric Designs for Reducing Vibration of a Non-Pneumatic Wheel during High-Speed Rolling
Authors: Rutherford William , Bezgam Shashank , Proddaturi Amarnath , Thompson Lonny , Ziegert John C. , Rhyne Timothy B. , Cron Steven M. 
Published: December 2010

Abstract
During high speed rolling of a nonpneumatic wheel, vibration may be produced by the interaction of collapsible spokes with a shear deformable ring as they enter the contact region, buckle, and then snap back into a state of tension. In the present work, a systematic study of the effects of six key geometric design parameters is presented using Orthogonal Arrays. Orthogonal Arrays are part of a design process method developed by Taguchi which provides an efficient way to determine optimal combinations of design variables. In the present work, a two-dimensional planar finite element model with geometric nonlinearity and explicit time-stepping is used to simulate rolling of the nonpneumatic wheel. Vibration characteristics are measured from the FFT frequency spectrum of the time signals of perpendicular distance of marker nodes from the virtual plane of the spoke, and ground reaction forces. Both maximum peak amplitudes and RMS measures are considered. Two complementary Orthogonal Arrays are evaluated. The first is the L8 orthogonal array which considers the six geometric design variables evaluated at lower and higher limiting values for a total of eight experiments defined by statistically efficient variable combinations. Based on the results from the L8 orthogonal array, a second L9 orthogonal array experiment evaluates the nonlinear effects in the four parameters of greatest interest, (a) spoke length, (b) spoke curvature, (c) spoke thickness, and (d) shear beam thickness. The L9 array consists of nine experiments with efficient combinations of low, intermediate, and high value levels. Results from use of the Orthogonal Array experiments were used to find combinations of parameters which significantly reduce peak and RMS amplitudes, and suggest that spoke length has the greatest effect on vibration amplitudes.
Pressure Release and Glacial Erosion
Authors: Lewis W. V. 
Published: December 2010

AbstractTwo tunnels were dug through a small cirque glacier to the rock wall behind (a) the névé, and (b) the lower glacier. The upper tunnel revealed shattering of the rock wall due to the freezing of melt water. The bedrock at the end of the lower tunnel was both smoothed and fractured. The problem is to account for the fracturing of the resistant gneiss where the temperature remains at 0° C. throughout the year. The solution offered is that the release of pressure beneath a thick glacier immediately downstream from a roche moutonnée, or from a small steep step, enables the stresses locked within the gneiss to crack the rock. These stresses result from the gradual removal of the overburden, since the gneiss consolidated under the pressure of thousands of metres of rock strata. The glacier can later remove the jointed and broken rock.
Studies in Glacier Physics on the Penny Ice Cap, Baffin Island, 1953: Part II: Portable Ice-Boring Equipment
Authors: Ward W. H. 
Published: December 2010

AbstractThe construction and use of some portable ice-boring equipment are described. The total weight of equipment for boring to a depth of 20 m. is about 36 kg. The weight increases by 1 kg. for each extra metre of depth.
Investigations in Vestspitsbergen
Authors: Dineley D. L. 
Published: December 2010

AbstractDeep, partly snow-filled gullies cutting the sea cliffs of part of the Vestspitsbergen strandflat are noted. They do not appear to have been cut by streams, and it is suggested that a process of frost action and snowpatch erosion has been largely responsible for their formation.A short note on glacial recession in part of Vestspitsbergen is added.
Results of Preliminary Experiments on the Plasticity of Ice Crystals
Authors: Steinemann Samuel 
Published: December 2010

AbstractThe growth of single crystals of ice for the study of plasticity has to be done with care, since a disturbing lineage structure is easily generated. The orientation of specimens can be found from growth figures (dendrites) and Tyndall’s “flowers”; these give thea-axis, as the branches in both cases point in the [1120] direction. Slip occurs on the basal plane without following a definite glide direction. In pure shear two stages of creep exist, the first for a glide of 10–20 per cent in an undeformed crystal, the second for greater shears having a higher creep velocity. Both stages obey the law,nbeing 2.3–4 in the first case and 1.3–1.8 in the second. The deformed state above the transition remains stable and no recrystallization takes place in pure shear. Restoration of the undeformed state by recrystallization occurs only in inhomogeneously deformed parts. This observation may have an influence in interpreting measurements of glacier movements and tests on polycrystalline specimens in the laboratory.
Internal Temperatures of a Cold Glacier and Conclusions Therefrom
Authors: Fisher Joel E. 
Published: December 2010

AbstractDescription of a horizontal tunnel driven through a cold, steeply sloping glacier, altitude 14,000 feet (4267 m.) on Monte Rosa, from its surface right through to bedrock, a distance of 302 feet (42 m.). Temperatures found deep within this cold glacier were 18° F. (−7.78° C.) compared with 8° F. (−13.33° C.) near its surface, and again near contact with its rock bed. This internal heat is interpreted as heat supplied from the interior of the earth, and as indicative of existence of ice at pressure-melting-point in all cold ice glaciers, if thickness of ice is sufficient. Existence of such an underlay of ice at pressure-melting-point, varying in distribution with varying supply of internal heat, is shown to explain (1) cirque erosion, (2) uniform elevation of cirques in any one region, (3) existence of extrusion flow under certain conditions, and (4) control of cycles of continental glaciation, under extreme limits.
Some Observations on the Banding of Glacier Ice
Authors: Untersteiner N. 
Published: December 2010

AbstractThe distribution of fine banding (foliation) on the surface of a flat glacier tongue was studied. The conclusions reached are that fine banding seems to be neither of sedimentary origin nor to be the representation of a straightforward stress system. In the present case, foliation seems to be connected with ice falls.Other bands definitely not belonging to the fine banding system were plotted irrespective of their outward appearance. Statistically, their preferred spacial directions correspond to the directions of either maximum shear stress or maximum normal stress (tension).
Observations of Freeze-Up and Break-Up of the Yukon River at Beaver, Alaska
Authors: Williams R. John 
Published: December 2010

AbstractObservations of fall freeze-up and spring break-up, important to subarctic hydrology and to local economy, were made at the Yukon River town of Beaver, Alaska, September 1949 to June 1950. On October 15, with river temperature at 0° C., the freezing together of floating ice crystals formed thin ice pans that gradually thickened. Falling river level and increasingly heavy ice concentration choked off all but main channels. On 25 October ice jammed downstream and produced a continuous ice cover and a temporary rise of about 1 m. at Beaver. After 26 October the river resumed its drop in level until April. Freeze-up appears governed by local channel, current and weather conditions and lacks systematic progression either upstream or downstream.Spring thaw beginning in late April thawed snow cover and weakened river ice. In early May the river began to rise slowly, but at an increasing rate, until 13 May when ice was nearly free from shore. On 14 May, after a rise of about 3 m. in 24 hours, the ice broke and moved downstream as the flood crest passed Beaver. Downstream progression of break-up is delayed by local ice jams, the chief cause of disastrous river floods, and is advanced by early break-up of large tributaries.
Measurements of Ablation and Heat Balance On Alpine Glaciers: With some remarks on the cause of glacier recession in the Alps
Authors: Hoinkes H. 
Published: December 2010

AbstractMeasurements of heat balance and ablation on glaciers of the Eastern Alps carried out during a total of 45 days since the summer of 1950 indicate that in flat glaciated areas at approximately 3000 m. above sea level 81 to 84 per cent of the energy causing ablation is supplied by short wave radiation from the sun and sky. Only 16 to 19 per cent come from the air in the form of actual and latent heat. On glacier tongues at altitudes of approximately 2300 m. the percentage of ablation caused by radiation is only 58 to 65 per cent. This is primarily the result of the shortened duration of sunshine in the deeper valleys. The supply of perceptible and latent heat from the air can, at most, reach a value of 15 to 30 per cent on glacier tongues. Evaporation from the ice and heat supply by liquid precipitation are negligible during the normal ablation period (June till September).It is to be expected therefore that the alpine glaciers will primarily react to variations of radiation and albedo during the months of June to September. The effects of changing summer temperatures are considered insufficient to cause the vast changes of the ice-cover. The variations of the duration of summer sunshine and the number of days with snowfall as a rough indication of albedo, respectively, are in perfect agreement with the behaviour of alpine glaciers during the last sixty years.
The Grinnell and Terra Nivea Ice Caps, Baffin Island
Authors: Mercer J. H. 
Published: December 2010

AbstractThe Grinnell and Terra Nivea Ice Caps are the southernmost in eastern North America. The Grinnell Ice Cap reaches an altitude of 870 m. (2854 ft.). The general tendency is for slight retreat, but one large glacier is advancing. The equilibrium line is considerably lower than on the Penny Ice Cap to the north. Both firn and superimposed ice are important in the economy.
Glaciers of the Washington Cascade and Olympic Mountains; Their Present Activity and its Relation to Local Climatic Trends
Authors: Hubley Richard C. 
Published: December 2010

AbstractBetween 1953 and 1955, 73 glaciers in the Olympic and Cascade Mountains of Washington State have been investigated to determine their present activity. 50 of these glaciers are now advancing at rates from 3 to 100 m. or more per annum. Of the remaining 23, 22 glaciers either demonstrate clear evidence of increasing thickness, or have remained so heavily snow-covered at the end of the ablation season that it has not been possible to locate their limits.The present glacier growth, which appears to have started about 12 years ago, represents a radical change from conditions during the previous 20 years when glaciers of the Olympics and Cascades without exception were shrinking rapidly. An analysis of local climatic data demonstrates a present trend toward a cooler, wetter climate in western Washington. The ten year running mean annual temperature at Tatoosh Island off the Washington coast has decreased approximately o 8° C. from the period 1934–1943 to the period 1945–1954. In the same interval of time the ten year running mean annual precipitation at Tatoosh has increased about 38 cm., and during the last decade has reached its highest value since the period 1898–1907.
Mapping of the Topography of Continental Ice by Inversion of Satellite-altimeter Data
Authors: Remy F. , Mazzega P. , Houry S. , Brossier C. , Minster J.F. 
Published: December 2010

AbstractSatellite-altimeter data over ice sheets provide the best tool for mapping their topography and its possible climatic variations. However, these data are affected by measurement errors, orbit errors, and slope errors. We develop here a three-step inversion technique which accommodates the a priori information on the expected topography and correctly handles and propagates the data errors: it estimates first a large-scale reference surface, then maps the residuals related to undulations, and finally iteratively corrects the slope error. The method is tested on overlapping small fragments of the Antarctic ice sheet, using a sub-set of Seasat data. Finally, a topographic map of Terre Adélie is produced. Over areas of small slopes, the a posteriori error should be of the order of 0.4 m. Using ERS-I data, it is therefore expected that climatic variations in the ice-sheet topography since the introduction of Seasat will be observable.
Ice-Shelf Response to Ice-stream Discharge Fluctuations: III. The Effects of Ice-stream Imbalance on the Ross Ice Shelf, Antarctica
Authors: Macayeal Douglas R. 
Published: December 2010

AbstractA numerical simulation of the Ross Ice Shelf, Antarctica, in which discharge from Ice Streams A-E is changed suddenly between extreme states, is used to investigate ice-shelf thickness and flow anomalies generated by ice-stream transience. At one extreme, ice-stream discharge rates specified as model boundary conditions are balanced individually with snow accumulation in the ice-stream catchment areas. At the other, discharge rates are fixed at current observed values which widely depart from mass balance. The simulated ice-shelf evolution between initial and final steady states suggests that ice-thickness and velocity fields adjust to new ice-stream conditions over a relatively short time span (approximately 500 years). In contrast, transitory geometrics of medial moraines and relict-crevasse bands persist over a longer time span (up to 2000 years). Contortions of medial moraines and relict-crevasse bands thus may provide a useful long-term history of past ice-stream activity. The past stoppage of Ice Stream C, for example, should be evident today in some medial moraine trajectories even if the stoppage occurred over 1000 years ago. Ice-shelf thickness fluctuations induced by ice-stream activity are generally restricted to the neighborhood of the grounding line. These fluctuations may constitute a trigger for ice-rise formation near ice-stream outlets.
Force Budget: I. Theory and Numerical Methods
Authors: Van Der Veen C.J. , Whillans I.M. 
Published: December 2010

AbstractA practical method is developed for calculating stresses and velocities at depth using field measurements of the geometry and surface velocity of glaciers. To do this, it is convenient to partition full stresses into lithostatic and resistive components. The horizontal gradient in vertically integrated lithostatic stress is the driving stress and it describes the horizontal action of gravity. The horizontal resistive stress gradients describe the reactions. Resistive stresses are simply related to deviatoric stresses and hence to strain-rates through a constitutive relation.A numerical scheme can be used to calculate stresses and velocities from surface velocities and slope, and from ice thickness. There is no mathematical requirement that the variations in these quantities be small.
18O Concentrations In Sea Ice Of The Weddell Sea, Antarctica
Authors: Lange Μ.A. , Schlosser P. , Ackley S.F , Wadhams P. , Dieckmann G.S. 
Published: December 2010

AbstractWe present data on ice texture, salinity, and δ18O obtained from identical sections of ice cores during the Winter Weddell Sea Project 1986 on RV Polarstern from July through August 1986, in the longitude range between 5°W. and 7°E. We find no uniquely definable relationship between δ18O values and ice texture in a particular section. However, most of the snow ice as well as some sections of frazil ice are found to have negative δ18O concentrations. This is due to varying degrees of admixtures of meteoric ice (snow) and sea-water during formation of snow ice. In contrast to common assumptions, our results seem to indicate that a snow cover contributes positively to sea-ice growth rather than slowing down the overall growth rate. Based on a simple model, we have estimated the contributions of meteoric ice (mean of 3 ± 3%) and the combined meteoric ice/sea-water fraction (a minimum of 7 ± 6%) to the total ice thickness for the majority of the sampled floes. Although this is only a moderate contribution to the overall mass balance, in the absence of congelation growth it nevertheless enhances ice growth in general. This hypothesis is independently supported by our snow- and ice-thickness data (Wadhams and others, 1987), which demonstrate that the depression of the snow/ice interface below the water line (i.e. a negative freeboard) and the formation of snow ice is a common occurrence in the Weddell Sea. Therefore, we hypothesize that the major part of the observed apparent increase in ice thickness between our inbound and outbound tracks of WWSP’86 may not be derived from “regular”, thermodynamically driven congelation growth, but rather from the snow-ice component in floes of the Weddell Sea.
A Subglacial Boundary-layer Regelation Mechanism
Authors: Shoemaker E.M. 
Published: December 2010

AbstractHeat input to basal ice at subglacial low-pressure regions, such as exist on the lee side of bed bumps including regions of ice-bed separation, is shown to melt basal ice internally in a narrow boundary layer at most centimeters thick. Before ice at the ice-bed interface can begin to melt, the heat input Q must exceed a critical value Q*. Q* increases rapidly with an increase in the difference ΔΡ between the nominal (global) overburden pressure and the magnitude of the (local) normal stress acting between the ice and bed or ice and water pocket. Because of the non-linear nature of the flow law, the thickness of the boundary layer decreases rapidly with increasing ΔΡ. The ice in the boundary layer is likely to be soft with a high water content. Under certain conditions, a regelation cycle may exist between the boundary layer and the water in a subglacial cavity. The boundary layer is sufficiently narrow that the processes can reach steady state while ice traverses subglacial low-pressure regions of length the order of 0.01–0.1 m. The regelation phenomenon may preserve or aid the formation of narrow debris-rich ice layers at the base of temperate glaciers.
Hot-water Drilling And Bore-hole Closure In Cold Ice
Authors: Humphrey Neil , Echelmeyer Keith 
Published: December 2010

AbstractDrilling bore holes in deep, cold ice masses by hot-water methods and maintaining these holes with sufficient diameter to allow down-hole experimentation poses a major obstacle to the investigation of conditions beneath ice sheets and ice streams. Closure of the water-filled holes by refreezing is the dominant difficulty. In this paper, we describe calculations of heat transfer from the drilling system to the ice and the subsequent time-dependent motion of the phase boundary defining the bore-hole wall. Results are presented with the view of optimizing the bore-hole radius at depth for a fixed drill performance and a variable rate of drilling.Calculation of melting/refreezing rates at the bore-hole wall requires the use of a one-dimensional, time-dependent numerical heat-flow model with a distorting mesh which follows the changing hole size. The delay of hole closure is discussed with a view to keeping holes open long enough to allow instruments to be lowered to the glacier bed, while realizing that drilling-system performance may be marginal because of logisitical and/or expenditure constraints. The relative merits of drilling a large hole, which is very time consuming with a small drill, and the use of water-soluble antifreezes, which have a history of creating plugs of ice slush, are discussed. A method of creating a stable hole filled with antifreeze in which ice slush does not occur is described.The recent application of these theoretical ideas to the planning and implementation of successful hot-water drilling programs in Antarctica and Greenland is also presented.