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A Pressure Relaxation Closure Model for One-Dimensional, Two-Material Lagrangian Hydrodynamics Based on the Riemann Problem

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Communications in Computational Physics 2010年第5期7卷 927-976页

作者： james R.Kamm Mikhail j.Shashkov Applied Physics Division Los Alamos National LaboratoryLos AlamosNM 87545USA Theoretical Division Los Alamos National LaboratoryLos AlamosNM 87545USA

Despite decades of development, Lagrangian hydrodynamics of strengthfree materials presents numerous open issues, even in one dimension. We focus on theproblem of closing a system of equations for a two-material cell under the assumptionof a single velocity model. There are several existing models and approaches, eachpossessing different levels of fidelity to the underlying physics and each exhibitingunique features in the computed solutions. We consider the case in which the changein heat in the constituent materials in the mixed cell is assumed equal. An instantaneous pressure equilibration model for a mixed cell can be cast as four equations infour unknowns, comprised of the updated values of the specific internal energy andthe specific volume for each of the two materials in the mixed cell. The unique contribution of our approach is a physics-inspired, geometry-based model in which theupdated values of the sub-cell, relaxing-toward-equilibrium constituent pressures arerelated to a local Riemann problem through an optimization principle. This approachcouples the modeling problem of assigning sub-cell pressures to the physics associated with the local, dynamic evolution. We package our approach in the frameworkof a standard predictor-corrector time integration scheme. We evaluate our model using idealized, two material problems using either ideal-gas or stiffened-gas equationsof state and compare these results to those computed with the method of Tipton andwith corresponding pure-material calculations.

关键词： Lagrangian hydrodynamics compressible flow multi-material flow pressure relaxation

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Placement of removable metal biliary stent in post-orthotopic liver transplantation anastomotic stricture

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World j.urnal of Gastroenterology 2010年第28期16卷 3597-3600页

作者： Hoi-Poh Tee Martin W james Arthur j.Kaffes Gastroenterology Unit Medical Department Hospital Tengku Ampuan AfzanJalan Tanah Putih25100 KuantanPahangMalaysia Wolfson Digestive Disease Biomedical Re search Unit Nottingham NG7 2UHUnited Kingdom AW Morrow Gastroenterology and Live Centre Royal Prince Alfred HospitalMissenden RoadCamp erdownNSW 2050Australia

Postoperative biliary strictures are the most common cause of benign biliary stricture in Western countries, secondary to either operative inj.ry or bile duct anastomotic stricture following orthotopic liver transplantation(OLT).Surgery or endoscopic interventions are the mainstay of treatment for benign biliary *** aim to report the outcome of 2 patients with refractory anastomotic biliary stricture post-OLT,who had successful temporary placement of a prototype removable covered self-expandable metal stent(RCSEMS).These 2 patients(both men,aged 44 and 53 years)were given temporary placement of a prototype RCSEMS (8.5 Fr gauge delivery system,8 mm×40 mm stent dimensions)in the common bile duct across the biliary *** was no morbidity associated with stent placement and removal in these 2 *** parameters improved after the RCSEMS *** biliary patency was achieved in both the patients. No further biliary intervention was required within 14 and 18 mo follow-up after stent removal.

关键词： Anastomosis Biliary stent Biliary stricture Orthotopic liver transplantation Niti-S stent

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Recent Increased Warming of the Alaskan Marine Arctic Due to Midlatitude Linkages

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Advances in Atmospheric Sciences 2018年第1期35卷 75-84页

作者： james E.OVERLAND Muyin WANG Thomas j.BALLINGER NOAA/Pacific Marine Environmental Laboratory Seattle WA 98115USA j.int Institute for the Study of Atmosphere and Oceans University of Washington Seattle WA 98115USA Department of Geography Texas State UniversitySan Marcos TX 78666USA

Alaskan Arctic waters have participated in hemispheric-wide Arctic warming over the last two decades at over two times the rate of global warming. During 2008–13, this relative warming occurred only north of the Bering Strait and the atmospheric Arctic front that forms a north–south thermal barrier. This front separates the southeastern Bering Sea temperatures from Arctic air masses. Model proj.ctions show that future temperatures in the Chukchi and Beaufort seas continue to warm at a rate greater than the global rate, reaching a change of +4℃ by 2040 relative to the 1981–2010 mean. Offshore at 74°N, climate models proj.ct the open water duration season to increase from a current average of three months to five months by 2040. These rates are occasionally enhanced by midlatitude connections. Beginning in August 2014, additional Arctic warming was initiated due to increased SST anomalies in the North Pacific and associated shifts to southerly winds over Alaska, especially in winter 2015–16. While global warming and equatorial teleconnections are implicated in North Pacific SSTs, the ending of the 2014–16 North Pacific warm event demonstrates the importance of internal, chaotic atmospheric natural variability on weather conditions in any given year. Impacts from global warming on Alaskan Arctic temperature increases and sea-ice and snow loss, with occasional North Pacific support, are proj.cted to continue to propagate through the marine ecosystem in the foreseeable future. The ecological and societal consequences of such changes show a radical departure from the current Arctic environment.

关键词： Alaska North Pacific Arctic warm advection polar vortex

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Statistical distribution of geomechanical properties and‘Sweet Spots’identification in part of the upper Bakken

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Petroleum Research 2023年第3期8卷 301-308页

作者： Nelson R.K.Tatsipie james j.Sheng Texas Tech University United States

Completions and Reservoir Quality are two key attributes that are used to characterize nonconventional hydrocarbon *** is because,for optimum exploitation of these unconventional assets,horizontal wells need to be drilled in“Sweet Spots”(i.e.,regions where Completions and Reservoir Quality are both superior).One way to quantify these qualities is to use reservoir and geomechanical *** properties can be estimated on a location basis from well logs,and then mapped over terrain using geostatistical *** study presents a‘Sweet Spots’identification workflow based on three performance indexes(Storage Potential Index,Brittleness Index,and Horizontal Stress Index)that can be used to quantify CQ and *** performance indexes are computed from petrophysical property volumes(of Young's Modulus,Bulk Modulus,Shear Modulus,Poisson's Ratio,Minimum Horizontal Stress,Volume of Shale,Total Organic Carbon,Thickness,and Porosity)which are in turn computed from well logs and geostatistical *** the end,the study offers a method to compare the predicted“Sweet Spots”against available production data via their correlation *** resulting reasonable formation property maps,the successful identification of‘Sweet Spots’,and a correlation coefficient of 0.88(between the predicted“Sweet Spots”and well production data)point to the potential of the proposed effort.

关键词： Sweet spots Sequential Gaussian simulation Storage potential index Brittleness index Horizontal stress index

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Semi-transparent,flexible,and electrically conductive silicon mesh by capillarity-driven welding of vapor-liquid-solid-grown nanowires over large areas

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Nano Research 2020年第5期13卷 1465-1471页

作者： Thomas A.Celano Seokhyoung Kim David j.Hill james F.Cahoon Department of Chemistry University of North Carolina at Chapel HillChapel HillNC 27599-3290USA

Bottom-up synthesis of semiconductor nanowires(NWs)by the vapor-liquid-solid(VLS)mechanism has enabled diverse technological applications for these *** metallic NWs,however,it has been challenging to form large-area interconnected NW ***,we generate centimeter-scale meshes of mechanically and electrically interconnected Si NWs by sequentially growing,collapsing,and j.ining the NWs using a capillarity-driven welding *** fabricate meshes from VLS-grown NWs ranging in diameter from 20 to 100 nm and find that the meshes are three-dimensional with a thickness ranging from^1 to^10 microns depending on the NW *** extinction measurements reveal that the networks are semi-transparent with a color that depends on the absorption and scattering characteristics of individual ***,active voltage contrast imaging of both centimeter-and micron-scale meshes reveals widespread electrical *** a sacrificial layer,we demonstrate that the mesh can be liberated from the growth substrate,yielding a highly flexible and transparent *** transport measurements both on the growth substrate and on liberated,flexible films reveal electrical conduction across a centimeter scale with a sheet resistance of^160-180 kΩ/square that does not change significantly upon *** the ability to encode complex functionality in semiconductor NWs through the VLS process,we believe these meshes of networked NWs could find application as neuromorphic memory,electrode scaffolds,and bioelectronic interfaces.

关键词： semiconductor nanowire conductive network flexible electronics welding thermal annealing active-voltage contrast

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Progressive heterosis in genetically defined tetraploid maize

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j.urnal of Genetics and Genomics 2019年第8期46卷 389-396页

作者： j.cob D.Washburn Mitchell j.McElfresh james A.Birchler Division of Biological Sciences University of Missouri

Progressive heterosis, i.e., the additional hybrid vigor in double-cross tetraploid hybrids not found in their single-cross tetraploid parents, has been documented in a number of species including alfalfa,potato, and maize. In this study, four artificially induced maize tetraploids, directly derived from standard inbred lines, were crossed in pairs to create two single-cross hybrids. These hybrids were then crossed to create double-cross hybrids containing genetic material from all four original lines. Replicated fieldbased phenotyping of the materials over four years indicated a strong progressive heterosis phenotype in tetraploids but not in their diploid counterparts. In particular, the above ground dry weight phenotype of double-cross tetraploid hybrids was on average 34% and 56% heavier than that of the single-cross tetraploid hybrids and the double-cross diploid counterparts, respectively. Additionally,whole-genome resequencing of the original inbred lines and further analysis of these data did not show the expected spectrum of alleles to explain tetraploid progressive heterosis under the complementation of complete recessive model. These results underscore the reality of the progressive heterosis phenotype,its potential utility for increasing crop biomass production, and the need for exploring alternative hypothesis to explain it at a molecular level.

关键词： Maize Tetraploid Heterosis Dominance complementation Progressive heterosis

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Ground characterization and roof mapping: Online sensor signal-based change detection

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International j.urnal of Mining Science and Technology 2015年第6期25卷 905-913页

作者： Bahrampour Soheil Rostami j.mal Ray Asok Naeimipour Ali collins Craig Electrical Engineering Department The Pennsylvania State University Department of Energy and Mineral Engineering The Pennsylvania State University j. H. Fletcher & Co.TM

Measurement while drilling systems are becoming an important part of excavation operations for rock characterization and ground support design that require reliable information on rock strength and location ＆ frequency of j.ints or voids. This paper focuses on improving rock characterization algorithms for instrumented roof-boRer systems. For this purpose, an improved void detection algorithm is proposed, where the underlying theory is built upon the concept of mean change detection based on the feed pressure signals. In addition, the application of acoustic sensing for void detection is examined and it is shown that the variance of the filtered acoustic signal is correlated to the strength of the material being drilled. The proposed algorithm has been validated on the data collected from full-scale drilling tests in various concrete and rock samples at the j. H. Fletcher facility.

关键词： Measurement while drilling systemsRoof mappingVoid detectionOnline change detection

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Root Canals and Crowns: An Analysis of the Spatial Distribution of Dental Offices in Ciudad j.árez, Chihuahua, Mexico, 1996-2011

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International j.urnal of Geosciences 2013年第6期4卷 38-43页

作者： Patricia j. Boda james Harris Department of Earth and Atmospheric Sciences Metropolitan State University Denver USA Department of Geosciences Middle Tennessee State University Murfreesboro USA

Every city above a certain size has health services that are located, to a large extent, close to their patients. This study analyzes the spatial distribution of dental office and the change in the number of dental offices in Ciudad j.árez, Chihuahua, Mexico over a 15-year time period. Research was conducted in 1996 and 2011. Maps showing the location of dental offices for these two years indicate a clustering of dental offices within one and one-half miles of the city’s two principal border-crossing points between the United States and Mexico. Provider-based surveys were also used to determine the mix of patients (US or Mexican citizens) at the dental offices found throughout the city. By 2011, nearly all of the dental offices clustered within one and one-half miles of the two principal US-Mexico border crossings had 100% of their patients from the United States.

关键词： Cross-Border Health Care Medical Geography US-Mexico Border Dental

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Understanding temporal stability:a long-term analysis of USDA ARS watersheds

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International j.urnal of Digital Earth 2021年第10期14卷 1243-1254页

作者： Evan j.Coopersmith Michael H.Cosh Patrick j.Starks David D.Bosch Chandra Holifield collins Mark Seyfried Stan Livingston j.hn Prueger Soil Insight LLCWashington D.C.USA USDA-Agricultural Research Service Beltsville Agricultural Research CenterHydrology and Remote Sensing LaboratoryBeltsvilleUSA USDA-Agricultural Research Service-Grazinglands Research Laboratory El RenoUSA USDA-Agricultural Research Service-Southeast Watershed Research Laboratory TiftonUSA USDA-Agricultural Research Service-Southwest Watershed Research Center TucsonUSA USDA-Agricultural Research Service-Northwest Watershed Research Laboratory BoiseUSA USDAAgricultural Research Service-National Soil Erosion Research Laboratory West LafayetteUSA USDA-Agricultural Research Service-National Laboratory for Agriculture and Environment AmesUSA

The *** of Agriculture’s Agricultural Research Service(USDAARS)maintains seven in situ soil moisture networks throughout the continental United States,some since *** networks are crucial for understanding the spatial and temporal extent of droughts in their historical context,parameterization of hydrologic models,and local agricultural decision ***,the estimates from these networks are dependent upon their ability to provide reliable soil moisture information at a large *** is also not known how many network stations are sufficient to monitor watershed scale ***,the obj.ctives of this research were to:(1)determine how temporally stable these networks are,including the relationships between various sensors on a year-to-year and seasonal basis,and(2)attempt to determine how many sensors are required,within a network,to approximate the full network *** data from seven in situ,it is concluded that approximately 12 soil moisture sensors are sufficient in most environments,presuming their locations are distributed to capture the hydrologic heterogeneity of the *** is possible to install a temporary network containing a suitable number of sensors for an appropriate length of time,glean stable relationships between locations,and retain these insights moving forward with fewer sensor resources.

关键词： Soil moisture temporal stability in situ networks

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Adenosine-treated bioprinted muscle constructs prolong cell survival and improve tissue formation

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Bio-Design and Manufacturing 2021年第3期4卷 441-451页

作者： Dongxu Ke Adam M.j.rgensen Sang j.Lee james j.Yoo Sean V.Murphy Wake Forest Institute for Regenerative Medicine Wake Forest School of MedicineWinston-SalemNCUSA Novaprint Therapeutics Suzhou Co. LtdSuzhouJiangsuChina

It is crucial to maintaining the viability of biofabricated human-sized tissues to ensure their successful survival and function after *** is a purine nucleoside that has the function to suppress cellular metabolism and has been previously proposed as a method to prolong cell viability under *** this study,we optimized the dose concentration of adenosine for incorporation into bioprinted constructs to preserve long-term cell viability in *** results showed that muscle cells(C2C12)containing 6,7,or 8 mM adenosine maintained high cell viability for 20 days under hypoxic conditions(0.1%O2),whereas cells without adenosine treatment showed 100%cell death after 11 *** 20 days under hypoxic conditions,muscle cells treated with adenosine proliferated and differentiated when transferred to normoxic *** these adenosine concentrations,6 mM was picked as the optimized adenosine concentration for further investigations due to its most effective results on improving cell *** bioprinted muscle constructs containing adenosine(6 mM)maintained high cell viability for 11 days under hypoxic conditions,while the control constructs without adenosine had no live *** in vivo validation,the bioprinted constructs with adenosine implanted under the dorsal subcutaneous space in mice,showed the enhanced formation of muscle tissue with minimal central necrosis and apoptosis,when compared to the constructs without *** positive in vitro and in vivo results demonstrate that the use of adenosine is an effective approach to preventing the challenge of hypoxia-induced necrosis in bioprinted tissues for clinical translation.

关键词： Bioprinting Hypoxia Adenosine Cell viability In vivo

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