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Effect of calcination temperature on steam reforming activity of Ni-based pyrochlore catalysts

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j.urnal of Rare Earths 2020年第7期38卷 711-718,I0002页

作者： Daniel j.Haynes Dushyant Shekhawat David Berry Amitava Roy james j.Spivey National Energy Technology Laboratory U.S.Department of Energy3610 Collins Ferry RdMorgantownWV26507 USA Louisiana State University Cain Department of Chemical Engineering3307 Patrick Taylor HallBaton RougeLA70803USA

This work served as the second part of a study evaluating the effect of calcination temperature(700-1000℃) on Ni-based lanthanum zirconate pyrochlore catalysts for methane steam reforming.A previous study(Haynes et ***.2017(43) 16744) provided a thorough characterization of the material properties for the catalysts used here,and this study focuses on the evaluation of catalytic *** activity was assessed by two different experimental studies:the effect of reaction temperature using a temperature programmed surface reaction(TPSR),and the effect of reaction *** results demonstrate a complex interaction between the Ni particles and surface LaOx species under the methane steam reforming ***,the material calcined at the lowest temperature(700℃) possesses the highest activity and selectivity,which is attributed to smaller and more welldispersed Ni particles on the surface,and,more importantly,a lesser degree La enrichment at the *** catalysts were deactivated by steam to NiO under all conditions tested,but at certain low reaction pressure(p=0.23 MPa) conditions the materials calcined at 700-900℃ are able to completely recover equilibrium activity in-situ that is then robust and stable under both low and high reaction pressures(p=1.8 MPa) suggesting the formation of a synergistic relationship between Ni and La for syngas ***,exposure of a fresh material to high reaction pressures leads to a rapid and irreversible loss in both CH4 conversion and syngas selectivity whether in the fresh(no pretreatment),or pretreated(steam,H2 or Ar only at 800℃) form for any *** mechanism for deactivation appears to be due to the presence of LaOx species that become mobile,possibly by the formation of La-OH,and covers the active Ni particles and inhibits sites responsible for the CH4 decomposition.

关键词： Nickel Pyrochlore Methane Steam reforming Catalyst Lanthanum enrichment

Further discussion of CO_(2) huff-n-puff mechanisms in tight oil reservoirs based on NMR monitored fluids spatial distributions

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Petroleum Science 2023年第1期20卷 350-361页

作者： Wei-Yu Tang james j.Sheng Ting-Xue j.ang Unconventional Petroleum Research Institute China University of PetroleumBeijing102249China Bob L.Herd Department of Petroleum Engineering Texas Tech UniversityLubbockTX79409USA Sinopec Research Institute of Petroleum Engineering Beijing100101China

Due to the poor physical properties of tight reservoirs,CO_(2) huff-n-puff(HNP)is considered a potential enhanced oil recovery(EOR)method after primary *** plays a critical role in the effective implementation of CO_(2) *** the optimization requires a good understanding of the EOR *** this work,the spatial distribution of oil saturation under different experimental conditions was analyzed by the NMR method to further discuss the HNP *** to the variation of 1D frequency signal amplitude,we divided the core into the hardly movable area and movable area,the region with the obvious signal decline was defined as the movable area,and the hardly movable area was the region with limited signal *** on that the recovery characteristics of different scenarios were ***,the necessity of the soaking stage was studied,where three scenarios with different soaking times were carried ***,the inj.ction pressure was adj.sted to investigate the effect of the pressure *** T_(2) spectra show that soaking has significantly improved the production of crude oil in small pores,and higher oil recovery in a single cycle is observed,but it is lower when the elapsed time(total operation time)is the same.31.03% of oil can be recovered after 3 cycles HNP,which increases to 33.8% and 37.06% for the 4 cycles and 6 cycles *** the pressure gradient increases,more oil is removed out of the matrix,and the oil in the deep part of the reservoir can be effectively *** the CO_(2) huff-n-puff process,the oil distributions are similar to the solution gas drive,the residual oil is distributed at the close end of the core and the range that the oil can be efficiently recovered is limited.

关键词： Tight reservoirs Low-field nuclear magnetic resonance (NMR) CO_(2)huff-n-puff Enhanced oil recovery

Genomewide selection for fruit quality traits in apple: breeding insights gained from prediction and postdiction

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Horticulture Research 2023年第6期10卷 238-249页

作者： Sarah A.Kostick Rex Bernardo james j.Luby Department of Horticultural Science University of MinnesotaSaint PaulMN 55108USA Department of Agronomy and Plant Genetics University of MinnesotaSaint PaulMN 55108USA

Many fruit quality traits in apple(Malus domestica Borkh.)are controlled by multiple small-effect quantitative trait loci(QTLs).Genomewide selection(genomic selection)might be an effective breeding approach for highly quantitative traits in woody perennial crops with long generation times like *** goal of this study was to determine if genomewide prediction is an effective breeding approach for fruit quality traits in an apple scion breeding *** apple scion breeding germplasm(nindividuals=955),high-quality single nucleotide polymorphism(SNP)data(nSNPs=977),and breeding program fruit quality trait data at harvest were *** parents‘Honeycrisp’and‘Minneiska’were highly *** to high predictive abilities were observed for most fruit quality traits at *** example,when 25%random subsets of the germplasm set were used as training sets,mean predictive abilities ranged from 0.35 to 0.54 across ***,training and test sets,family size for within family prediction,and number of SNPs per chromosome affected model predictive *** of large-effect QTLs as fixed effects resulted in higher predictive abilities for some traits(*** red overcolor).Postdiction(***)analyses demonstrated the impact of culling threshold on selection *** results of this study demonstrate that genomewide selection is a useful breeding approach for certain fruit quality traits in apple.

关键词： breeding germplasm crops

Therapeutics to harness the immune microenvironment in multiple myeloma

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Cancer Drug Resistance 2022年第3期5卷 647-661页

作者： james j.Ignatz-Hoover james j.Driscoll University Hospitals Seidman Cancer CenterClevelandOH 44106USA Department of Biochemistry Case Western Reserve UniversityClevelandOH 44106USA Hematopoietic and Immune Cancer Biology Program Case Comprehensive Cancer CenterCase Western Reserve UniversityClevelandOH 44106USA

Multiple myeloma(MM)remains an incurable,genetically heterogeneous disease characterized by the uncontrolled proliferation of transformed plasma cells nurtured within a permissive bone marrow(BM)*** therapies leverage the unique biology of MM cells and target the immune microenvironment that drives tumor growth and facilitates immune *** inhibitors and immunomodulatory drugs were initially introduced to complement and have now supplanted cytotoxic chemotherapy as frontline anti-myeloma ***,monoclonal antibodies,bispecific antibodies,and chimeric antigen receptor T cells were developed to revamp the immune system to overcome immune suppression and improve patient *** current MM therapies have markedly extended patient survival,acquired drug resistance inevitably emerges and drives disease *** logical progression for the next generation of MM therapies would be to design and validate agents that prevent and/or overcome acquired resistance to *** complex BM microenvironment promotes resistance to both current anti-myeloma agents and emerging *** cells are intertwined with a complex BM immune microenvironment that contributes to the development of adaptive drug ***,we describe recently FDA-approved and investigational anti-myeloma agents that directly or indirectly target the BM microenvironment to prevent or overcome drug *** effects of anti-myeloma agents may foster the development of rationally-designed drug cocktails that prevent BM-mediated resistance to immunotherapies.

关键词： Multiple myeloma drug resistance proteasome inhibitors immunomodulators immunotherapeutics adaptive resistance bone marrow microenvironment

Intraspecific temporal resource partitioning at white-tailed deer feeding sites

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Current Zoology 2019年第2期65卷 139-146页

作者： David B. STONE james A. MARTIN Bradley S. COHEN Thomas j. PREBYL Charlie KILLMASTER Karl V. MILLER Warnell School of Forestry and Natural Resources University of Georgia Athens GA USA Savannah River Ecology Lab University of Georgia Aiken SC USA Department of Biology Tennessee Technological University Cookeville TN USA Georgia Department of Natural Resources Atlanta GA USA

Individuals may reduce competition by temporally partitioning their use of a shared resource. Behavioral differences between sexes in ungulates may encourage segregation as individuals attempt to avoid antagonistic interactions. However, dominant sex and age groups may reduce subordinates' access to food resources, regardless of the subordinate's sex. We hypothesized that white-tailed deer Odocoileus Virginian us temporally segregated at supplemental feedi ng sites based on social rank (subordinate: yearling males and adult females;dominant: adult males) and that segregation was affected by phase of the breeding season and diel cycle. If deer temporally segregate according to social rank, we predicted that the resulting activity patterns would manifest in one social class being relatively more susceptible to hunter-induced mortality. We used a multistate modeling approach to quantify temporal segregation and calculated the probability that a feeding site was in a particular state during diurnal and nocturnal hours for each of the 3 phases of the breeding season. We determined that transition probabilities differed by season and diel cycle and dominant and subordinate social classes clearly avoided each other, with <1% co-occurrenee at feedi ng sites. During the pre-breedi ng seas on, the probability of a subordi nate being present during diurnal hours was *** more likely than a dominant being present, but did not differ during nocturnal hours. There was no difference for dominants and subordinates during diurnal or no cturnal hours during the breedi ng season .In the post-breedi ng season, subordi nates were 1.7x more likely to occur at the feeding site than a dominant during diurnal hours but they did not differ during nocturnal hours. Our results indicate that dominance status influences temporal segregation at feeding sites and is affected by the phase of the breeding season. Therefore, the resulti ng activity patterns may in crease subordi nates' risk to human

关键词： competition multistate modeling predation risk supplemental feeding sites intraspecific temporal resource partitioning white-tailed deer

Guidelines for the use of accelerated pavement testing data in autonomous vehicle infrastructure research

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j.urnal of Traffic and Transportation Engineering(English Edition) 2019年第3期6卷 273-281页

作者： WynAND j.vdM.Steyn james W.Maina Department of Civil Engineering University of Pretoria

There is much research conducted on the vehicle technologies required for operation of autonomous vehicles(AV) on public roads, as well as analysis of the interaction between AV and the road environment. However, limited research exists on the impact of AV on road pavement structures. The research includes issues such as the effect of more channelized traffic loading, shorter inter-vehicle following distances and potential higher traffic volumes of more uniform vehicle types and loads. This paper discusses the application of existing and generation of new, relevant accelerated pavement testing(APT) data in understanding the effects of AV on pavement infrastructure. The paper presents development of provisional guidelines for the use and application of APT data to ensure that road pavement structures cope with anticipated increase in AV use. It is concludes that the use of AV fleets on existing road pavement infrastructure may lead to different behaviors and responses than what became the norm under non-autonomous vehicle fleets;appropriate analysis of existing APT data will contribute to the improved understanding of these expected changes in behaviors and responses; appropriate planning of AV operations-focused APT is possible with existing technology to contribute to the provision of economic and durable road pavement infrastructure in future.

关键词： Autonomous vehicles Accelerated pavement testing Vehicle-pavement interaction Road infrastructure

Burrowing Richardson's ground squirrels affect plant seedling assemblages via environmental but not seed bank changes

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Current Zoology 2020年第3期66卷 219-226页

作者： Levi j.Newediuk james F.Hare Department of Biological Sciences University of ManitobaWinnipegManitobaCanada R3T 2N2

In grassland ecosystems,burrowing mammals create disturbances,providing habitat for animal species and increasing plant community *** investigated whether seedling assemblages on Richardson's ground squirrel Urocitellus richardsonii mounds result from seed rearrangement or environmental changes that favor germination of certain species over *** test whether ground squirrels rearrange the seed bank by burrowing,we compared seed compositions among mounds,burrows,and undisturbed *** test whether ground squirrels change environmental conditions,we compared soil nitrate and bare ground cover on and off *** also compared seedlings that germinated on mounds with seedlings that germinated on artificial disturbances from which we removed aboveground *** nitrate and bare ground cover were significantly higher on mounds than artificial *** seed richness and abundance did not differ among mounds,burrows,and undisturbed soil,seedling richness was reduced on mounds relative to artificial *** disturbance favors seedlings that can capitalize on bare ground availability but are less able to immobilize nitrate,as opposed to perennial species that immobilize more nitrate but take longer to *** results suggest that Richardson's ground squirrels act as ecosystem engineers,although future research following succession on ground squirrel mounds is necessary to understand how they influence plant communities past the seedling stage.

关键词： burrowing disturbance ecosystem engineering Richardsons ground squirrel seed bank seedling species composition

The importance of large-diameter trees to the creation of snag and deadwood biomass

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Ecological Processes 2021年第1期10卷 380-393页

作者： james A.Lutz Soren Struckman Sara j.Germain Tucker j.Furniss Department of Wildland Resources S.J.and Jessie E.Quinney College of Natural ResourcesUtah State University5230 Old Main HillLoganUT 84322-5230USA

Background:Baseline levels of tree mortality can,over time,contribute to high snag densities and high levels of deadwood(down woody debris)if fire is infrequent and decomposition is *** can be important for tree recruitment,and it plays a maj.r role in terrestrial carbon cycling,but deadwood is rarely examined in a spatially explicit ***:Between 2011 and 2019,we annually tracked all trees and snags≥1 cm in diameter and mapped all pieces of deadwood≥10 cm diameter and≥1 m in length in 25.6 ha of Tsuga heterophylla/Pseudotsuga menziesii *** analyzed the amount,biomass,and spatial distribution of deadwood,and we assessed how various causes of mortality that contributed uniquely to deadwood ***:Compared to aboveground woody live biomass of 481 Mg ha^(−1)(from trees≥10 cm diameter),snag biomass was 74 Mg ha^(−1) and deadwood biomass was 109 Mg ha^(−1)(from boles≥10 cm diameter).Biomass from large-diameter trees(≥60 cm)accounted for 85%,88%,and 58%,of trees,snags,and deadwood,*** aboveground woody live and dead biomass was 668 Mg ha^(−1).The annual production of downed wood(≥10 cm diameter)from tree boles averaged 4 Mg ha^(−1) yr^(−1).Woody debris was spatially heterogeneous,varying more than two orders of magnitude from 4 to 587 Mg ha^(−1) at the scale of 20 m×20 m *** all causes of deadwood creation varied in importance between large-diameter trees and small-diameter *** of standing stems and deadwood had weak inverse distributions,reflecting the long period of time required for trees to reach large diameters following antecedent tree mortalities and the centennial scale time required for deadwood ***:Old-growth forests contain large stores of biomass in living trees,as well as in snag and deadwood biomass pools that are stable long after tree *** biomass(or carbon)in deadwood pools can lead to substantial underestimations of sequestration and stability.

关键词： Carbon sequestration Old-growth forest Pseudotsuga menziesii Tree mortality Tsuga heterophylla Wind River Forest Dynamics Plot

Evaluating reservoir suitability for large-scale hydrogen storage:A preliminary assessment considering reservoir properties

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Energy Geoscience

Energy Geoscience 2024年第4期5卷 198-211页

作者： Chinedu j.Okere james j.Sheng Chinedu Ej.ke Bob L.Herd Department of Petroleum Engineering Texas Tech UniversityLubbockTX79409United States Mewbourne School of Petroleum and Geological Engineering University of OklahomaOK73019United States

With rising demand for clean energy,global focus turns to finding ideal sites for large-scale underground hydrogen storage(UHS)in depleted petroleum reservoirs.A thorough preliminary reservoir evaluation before hydrogen(H_(2))inj.ction is crucial for UHS success and *** criteria for UHS often emphasize economics and chemistry,neglecting key reservoir *** study introduces a comprehensive framework for the reservoir-scale preliminary assessment,specifically tailored for long-term H_(2) storage within depleted gas *** evaluation criteria encompass critical components,including reservoir geometry,petrophysical properties,tectonics,and formation *** illustrate the practical application of this approach,we assess the Barnett shale play reservoir *** assessment unfolds through three key stages:(1)A systematic evaluation of the reservoir's properties against our comprehensive screening criteria determines its suitability for H_(2) storage.(2)Using both homogeneous and multilayered gas reservoir models,we explore the feasibility and efficiency of H_(2) *** phase involves an in-depth examination of reservoir behavior during the inj.ction stage.(3)To enhance understanding of UHS performance,sensitivity analyses investigate the impact of varying reservoir dimensions and inj.ction/production *** findings reveal the following:(a)Despite potential challenges associated with reservoir compaction and aquifer support,the reservoir exhibits substantial promise as an H_(2) storage site.(b)Notably,a pronounced increase in reservoir pressure manifests during the inj.ction stage,particularly in homogeneous reservoirs.(c)Furthermore,optimizing inj.ction-extraction cycle efficiency can be achieved by augmenting reservoir dimensions while maintaining a consistent *** ensure a smooth transition to implementation,further comprehensive investigations are advised,including experimental and numerical studies to address

关键词： Site selection Underground hydrogen storage Preliminary evaluation Depleted petroleum reservoirs Reservoir assessment