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Sample records for hybrid aspen plantations

  1. Above-ground biomass characteristics of young hybrid aspen (Populus tremula L. x P. tremuloides Michx.) plantations on former agricultural land in Estonia

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    Tullus, Arvo; Tullus, Hardi; Soo, Tea; Paern, Linnar [Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, 51014 Tartu (Estonia)

    2009-11-15

    Fifty biomass production model trees were analysed in 7-yr-old commercial hybrid aspen plantations established on abandoned agricultural land in Estonia. Above-ground leafless biomass (ALB) of the model trees varied from 0.1 to 9.8 kg DM. The ALB of plantations with a density of 880-1340 trees ha{sup -1} growing on former field soils was between 2.18 and 8.54 t DM ha{sup -1}. The amount of nitrogen accumulated in the ALB varied between 14.4 and 48.5 kg ha{sup -1}, the amount of phosphorus, between 1.7 and 5.9 kg ha{sup -1}, and the amount of potassium, between 6.5 and 21.9 kg ha{sup -1}. The removal of major mineral nutrients from the site with the removal of woody biomass in 7-yr-old plantations would be relatively small, constituting 0.5-3.4% of the nutrient pool in the humus layer of the previously fertilized field soils. The stembark content decreases rapidly until the DBH reaches 4 cm, which can be considered a target diameter for the hybrid aspen coppicing system. (author)

  2. Fast-growing trees. Sub-project: Applicability of aspen and testing of aspen hybrids for biomass production in short-rotation plantations. Final report; Schnellwachsende Baumarten. Teilvorhaben: Eignung der Baumart Aspe und Pruefung von Aspenhybriden fuer die Biomasseerzeugung in Kurzumtriebsplantagen. Abschlussbericht

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    Muhs, H.J.; Liesebach, M.; Wuehlisch, G. von; Mulsow, H.; Korsch, M.; Duehring, C.; Rose, A.; Mecke, R.

    1997-06-01

    The suitability of aspen for short-rotation plantations on former agricultural surfaces was investigated according to the following criteria: Growth rate of young trees - biomass production - regeneration after harvesting - competitive strength - resistance to biotic and abiotic damage. The investigations were to find out the extent of variation between the selected varieties and the effects of site conditions. The results were to provide information on selection criteria for aspen in short-rotation plantations. For this purpose, 17 aspen varieties (offspring from crossing and tissue culture cloning) were planted in 4 sites with a total area of about 6.7 ha. Two willow clones and offspring of a Japanese beech were investigated as well. Annual reasurements are to provide information on growth as a function of site conditions, plant neighbourhoods and rotation time. The investigations were supplemented by the result obtained in earlier experimental aspen stands. Information on birds and invertebrate fauna on a short-rotation plantation is to be obtained as well. [Deutsch] Ziel der Versuche ist die Pruefung der Eignung der Aspe fuer die Produktionsform Kurzumtrieb auf zuvor landwirtschaftlich genutzten Flaechen. Geprueft wurden folgende Merkmale: - Jugendwachstum, - Biomasseproduktion, - Regeneration nach einer Beerntung, - Konkurrenzvertraeglichkeit, - Resistenz gegen biotische und abiotische Schaedigungen. Hierbei sollte festgestellt werden, wie gross die Variation zwischen den selektierten Sorten in relevanten Merkmalen ist und wie stark diese durch den Standort beeinflusst werden. Die Ergebnisse sollten Hinweise fuer Selektionskriterien fuer die in der Kurzumtriebswirtschaft einzusetzenden Aspen geben. Dazu wurden 17 Aspennachkommenschaften aus Kreuzungen und Klone aus Gewebekultur geprueft, die an 4 Standorten auf insgesamt rund 6,7 ha angebaut wurden. Weiterhin wurden 2 Weidenklone und Nachkommenschaften einer japanischen Birkenart hinsichtlich ihrer Eignung im

  3. Abaxial Greening Phenotype in Hybrid Aspen

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    Julia S. Nowak

    2013-04-01

    Full Text Available The typical angiosperm leaf, as in Arabidopsis, is bifacial consisting of top (adaxial and bottom (abaxial surfaces readily distinguishable by the underlying cell type (palisade and spongy mesophyll, respectively. Species of the genus Populus have leaves that are either conventionally bifacial or isobilateral. Isobilateral leaves have palisade mesophyll on the top and bottom of the leaf, making the two sides virtually indistinguishable at the macroscopic level. In poplars this has been termed the “abaxial greening” phenotype. Previous work has implicated ASYMMETRIC LEAVES1 (AS1 as an essential determinant of palisade mesophyll development. This gene, as well as other genes (84 in all putatively involved in setting the dorsiventral axis of leaves, were investigated in two Populus species: black cottonwood (Populus trichocarpa and hybrid aspen (P. tremula x tremuloides, representative of each leaf type (bifacial and isobilateral, respectively. Poplar orthologs of AS1 have significantly higher expression in aspen leaf blade and lower in the petiole, suggestive of a potential role in the isobilateral leaf phenotype consistent with the previously observed phenotypes. Furthermore, an ABERRANT TESTA SHAPE (ATS ortholog has significantly lower expression in aspen leaf tissue, also suggesting a possible contribution of this gene to abaxial greening.

  4. Abaxial Greening Phenotype in Hybrid Aspen.

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    Nowak, Julia S; Douglas, Carl J; Cronk, Quentin C B

    2013-04-24

    The typical angiosperm leaf, as in Arabidopsis, is bifacial consisting of top (adaxial) and bottom (abaxial) surfaces readily distinguishable by the underlying cell type (palisade and spongy mesophyll, respectively). Species of the genus Populus have leaves that are either conventionally bifacial or isobilateral. Isobilateral leaves have palisade mesophyll on the top and bottom of the leaf, making the two sides virtually indistinguishable at the macroscopic level. In poplars this has been termed the "abaxial greening" phenotype. Previous work has implicated ASYMMETRIC LEAVES1 (AS1) as an essential determinant of palisade mesophyll development. This gene, as well as other genes (84 in all) putatively involved in setting the dorsiventral axis of leaves, were investigated in two Populus species: black cottonwood (Populus trichocarpa) and hybrid aspen (P. tremula x tremuloides), representative of each leaf type (bifacial and isobilateral, respectively). Poplar orthologs of AS1 have significantly higher expression in aspen leaf blade and lower in the petiole, suggestive of a potential role in the isobilateral leaf phenotype consistent with the previously observed phenotypes. Furthermore, an ABERRANT TESTA SHAPE (ATS) ortholog has significantly lower expression in aspen leaf tissue, also suggesting a possible contribution of this gene to abaxial greening.

  5. A site dependent top height growth model for hybrid aspen

    Institute of Scientific and Technical Information of China (English)

    Tord Johansson

    2013-01-01

    In this study height growth models for hybrid aspen were developed using three growth equations. The mean age of the hybrid aspen was 21 years (range 15−51 years) with a mean stand density of 946 stems ha-1 (87−2374) and a mean diameter at breast height (over bark) of 19.6 cm (8.5−40.8 cm). Site index was also examined in relation to soil type. Multiple samples were collected for three types of soil: light clay, medium clay and till. Site index curves were constructed using the col-lected data and compared with published reports. A number of dynamic equations were assessed for modeling top-height growth from total age. A Generalized Algebraic Difference Approach model derived by Cieszewski (2001) performed the best. This model explained 99% of the observed variation in tree height growth and exhibited no apparent bias across the range of predicted site indices. There were no significant differences between the soil types and site indices.

  6. Genetic variation of hydraulic and wood anatomical traits in hybrid poplar and trembling aspen.

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    Schreiber, Stefan G; Hacke, Uwe G; Hamann, Andreas; Thomas, Barb R

    2011-04-01

    Intensive forestry systems and breeding programs often include either native aspen or hybrid poplar clones, and performance and trait evaluations are mostly made within these two groups. Here, we assessed how traits with potential adaptive value varied within and across these two plant groups. Variation in nine hydraulic and wood anatomical traits as well as growth were measured in selected aspen and hybrid poplar genotypes grown at a boreal planting site in Alberta, Canada. Variability in these traits was statistically evaluated based on a blocked experimental design. We found that genotypes of trembling aspen were more resistant to cavitation, exhibited more negative water potentials, and were more water-use-efficient than hybrid poplars. Under the boreal field test conditions, which included major regional droughts, height growth was negatively correlated with branch vessel diameter (Dv ) in both aspen and hybrid poplars and differences in Dv were highly conserved in aspen trees from different provenances. Differences between the hybrid poplars and aspen provenances suggest that these two groups employ different water-use strategies. The data also suggest that vessel diameter may be a key trait in evaluating growth performance in a boreal environment.

  7. Use of Sulfometuron in Hybrid Poplar Energy Plantations

    Science.gov (United States)

    Daniel A. Netzer

    1995-01-01

    Reports that low rates of sulfometuron, 70 grams per hactare (1 ounce product or 0.75 ounces active ingredient per acre), applied when hybrid poplars are completely dormant, can provide season-long weed control and increase hybrid poplar growth. If plantation access is not possible before growth activity begins in the spring, late fall application of this herbicide...

  8. Biomass production of hybrid aspen growing on former farm land in Sweden

    Institute of Scientific and Technical Information of China (English)

    Tord Johansson

    2013-01-01

    We construct dry weight equations for hybrid aspen growing on former farmland in Sweden.Dry weight equations for fractions of hybrid aspen trees were also made.We estimated biomass production in 24 stands.The stands were located in Sweden at latitudes ranging from 55 to 60° N.The mean age was 18 years (range 15-23),the mean stand density 1090 stems·ha-1 (range 378-2374),and the mean diameter at breast height (over bark) 178 mm (range 85-244 mm).Soil types in the hybrid aspen stands were mainly clay (21 stands),tills (2 stands) and other (1 stand).The mean total standing dry weight above stump level (≈200 mm) for the hybrid aspen stands was 135±53 t·ha-1 with a range of 42-219 t·ha-1.In addition to estimating conventional dry weights of trees and tree components,basic density,specific leaf area (SLA),projected leaf area (PLA) and leaf area index (LAI) were estimated and were in agreement with published figures.

  9. Summer is the best time to thin hybrid poplar plantations

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    Harold F. Ford; Albert G., Jr. Snow

    1954-01-01

    Hybrid poplar plantations are established by planting dormant cuttings in close spacing, usually 4 x 4 feet. They are cultivated during the first growing season to eliminate competition from grasses and weeds. After the first year, the more vigorous trees effectively shade out lower vegetation. But rapid tree growth often makes thinning necessary after 2 or 3 growing...

  10. Gibberellins inhibit adventitious rooting in hybrid aspen and Arabidopsis by affecting auxin transport.

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    Mauriat, Mélanie; Petterle, Anna; Bellini, Catherine; Moritz, Thomas

    2014-05-01

    Knowledge of processes involved in adventitious rooting is important to improve both fundamental understanding of plant physiology and the propagation of numerous plants. Hybrid aspen (Populus tremula × tremuloïdes) plants overexpressing a key gibberellin (GA) biosynthesis gene (AtGA20ox1) grow rapidly but have poor rooting efficiency, which restricts their clonal propagation. Therefore, we investigated the molecular basis of adventitious rooting in Populus and the model plant Arabidopsis. The production of adventitious roots (ARs) in tree cuttings is initiated from the basal stem region, and involves the interplay of several endogenous and exogenous factors. The roles of several hormones in this process have been characterized, but the effects of GAs have not been fully investigated. Here, we show that a GA treatment negatively affects the numbers of ARs produced by wild-type hybrid aspen cuttings. Furthermore, both hybrid aspen plants and intact Arabidopsis seedlings overexpressing AtGA20ox1, PttGID1.1 or PttGID1.3 genes (with a 35S promoter) produce few ARs, although ARs develop from the basal stem region of hybrid aspen and the hypocotyl of Arabidopsis. In Arabidopsis, auxin and strigolactones are known to affect AR formation. Our data show that the inhibitory effect of GA treatment on adventitious rooting is not mediated by perturbation of the auxin signalling pathway, or of the strigolactone biosynthetic and signalling pathways. Instead, GAs appear to act by perturbing polar auxin transport, in particular auxin efflux in hybrid aspen, and both efflux and influx in Arabidopsis.

  11. A simple and efficient transient transformation for hybrid aspen (Populus tremula × P. tremuloides

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    Takata Naoki

    2012-08-01

    Full Text Available Abstract Background The genus Populus is accepted as a model system for molecular tree biology. To investigate gene functions in Populus spp. trees, generating stable transgenic lines is the common technique for functional genetic studies. However, a limited number of genes have been targeted due to the lengthy transgenic process. Transient transformation assays complementing stable transformation have significant advantages for rapid in vivo assessment of gene function. The aim of this study is to develop a simple and efficient transient transformation for hybrid aspen and to provide its potential applications for functional genomic approaches. Results We developed an in planta transient transformation assay for young hybrid aspen cuttings using Agrobacterium-mediated vacuum infiltration. The transformation conditions such as the infiltration medium, the presence of a surfactant, the phase of bacterial growth and bacterial density were optimized to achieve a higher transformation efficiency in young aspen leaves. The Agrobacterium infiltration assay successfully transformed various cell types in leaf tissues. Intracellular localization of four aspen genes was confirmed in homologous Populus spp. using fusion constructs with the green fluorescent protein. Protein-protein interaction was detected in transiently co-transformed cells with bimolecular fluorescence complementation technique. In vivo promoter activity was monitored over a few days in aspen cuttings that were transformed with luciferase reporter gene driven by a circadian clock promoter. Conclusions The Agrobacterium infiltration assay developed here is a simple and enhanced throughput method that requires minimum handling and short transgenic process. This method will facilitate functional analyses of Populus genes in a homologous plant system.

  12. Biomass and nitrogen dynamics in an irrigated hybrid poplar plantation

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    McLaughlin, R.A.

    1985-01-01

    A 3-year study measured the effects of ground cover treatments and nitrogen fertilization on biomass and nitrogen dynamics in an irrigated hybrid poplar (Populus deltoides Bartr. x P. trichocarpa Torr. and Gray, clone NC-9922) plantation in northern Wisconsin. Annually fertilized (112 kg N/ha/yr) and unfertilized plots were either maintained weed-free (bare soil), allowed to revegetate with native weeds, or seeded to birdsfoot trefoil (Lotus corniculatus L.). Trees in bare soil plots responded to fertilization primarily in the third growing season, but total biomass of 3-year-old trees was not increased by annual fertilization. High nitrate-nitrogen concentrations in the soil solution suggested significant leaching in both unfertilized and fertilized bare soil plots in the first growing season, and in fertilized plots the second season. Nitrate-nitrogen concentrations declined sharply in fertilized bare soil plots during the third growing season. Cover crop biomass was greatest in the second year and declined thereafter due to declines in below-ground components. Fertilization increased tree growth in these plots, but cover crop treatments had no effect. Results of this study suggest that, under irrigated conditions, a cover crop can substantially reduce leaching losses of nutrients and serve as a slow-release pool of nitrogen after the trees achieve crown closure. Fertilization is not recommended in these plantations until the second growing season if a cover crop is present and the third growing season if complete weed control is practiced.

  13. Spatial and temporal variability of xylan distribution in differentiating secondary xylem of hybrid aspen.

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    Kim, Jong Sik; Sandquist, David; Sundberg, Björn; Daniel, Geoffrey

    2012-06-01

    Xylans occupy approximately one-third of the cell wall components in hardwoods and their chemical structures are well understood. However, the microdistribution of xylans (O-acetyl-4-O-methylglucuronoxylans, AcGXs) in the cell wall and their correlation with functional properties of cells in hardwood xylem is poorly understood. We demonstrate here the spatial and temporal distribution of xylans in secondary xylem cells of hybrid aspen using immunolocalization with LM10 and LM11 antibodies. Xylan labeling was detected earliest in fibers at the cell corner of the S₁ layer, and then later in vessels and ray cells respectively. Fibers showed a heterogeneous labeling pattern in the mature cell wall with stronger labeling of low substituted xylans (lsAcGXs) in the outer than inner cell wall. In contrast, vessels showed uniform labeling in the mature cell wall with stronger labeling of lsAcGXs than fibers. Xylan labeling in ray cells was detected much later than that in fibers and vessels, but was also detected at the beginning of secondary cell wall formation as in fibers and vessels with uniform labeling in the cell wall regardless of developmental stage. Interestingly, pit membranes including fiber-, vessel- and ray-vessel pits showed strong labeling of highly substituted xylans (hsAcGXs) during differentiation, although this labeling gradually disappeared during pit maturation. Together our observations indicate that there are temporal and spatial variations of xylan deposition and chemical structure of xylans between cells in aspen xylem. Differences in xylan localization between aspen (hardwood) and cedar (softwood) are also discussed.

  14. Cloning and Overproduction of Gibberellin 3-Oxidase in Hybrid Aspen Trees. Effects on Gibberellin Homeostasis and Development1

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    Israelsson, Maria; Mellerowicz, Ewa; Chono, Makiko; Gullberg, Jonas; Moritz, Thomas

    2004-01-01

    To broaden our understanding of gibberellin (GA) biosynthesis and the mechanism whereby GA homeostasis is maintained in plants, we have investigated the degree to which the enzyme GA 3-oxidase (GA3ox) limits the formation of bioactive GAs in elongating shoots of hybrid aspen (Populus tremula × Populus tremuloides). We describe the cloning of a hybrid aspen GA3ox and its functional characterization, which confirmed that it has 3β-hydroxylation activity and more efficiently converts GA9 to GA4 than GA20 to GA1. To complement previous studies, in which transgenic GA 20-oxidase (GA20ox) overexpressers were found to produce 20-fold higher bioactive GA levels and subsequently grew faster than wild-type plants, we overexpressed an Arabidopsis GA3ox in hybrid aspen. The generated GA3ox overexpresser lines had increased 3β-hydroxylation activity but exhibited no major changes in morphology. The nearly unaltered growth pattern was associated with relatively small changes in GA1 and GA4 levels, although tissue-dependent differences were observed. The absence of increases in bioactive GA levels did not appear to be due to feedback or feed-forward regulation of dioxygenase transcripts, according to semiquantitative reverse transcription polymerase chain reaction analysis of PttGA20ox1, PttGA3ox1, and two putative PttGA2ox genes. We conclude that 20-oxidation is the limiting step, rather than 3β-hydroxylation, in the formation of GA1 and GA4 in elongating shoots of hybrid aspen, and that ectopic GA3ox expression alone cannot increase the flux toward bioactive GAs. Finally, several lines of evidence now suggest that GA4 has a more pivotal role in the tree hybrid aspen than previously believed. PMID:15122019

  15. Cloning and overproduction of gibberellin 3-oxidase in hybrid aspen trees. Effects on gibberellin homeostasis and development.

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    Israelsson, Maria; Mellerowicz, Ewa; Chono, Makiko; Gullberg, Jonas; Moritz, Thomas

    2004-05-01

    To broaden our understanding of gibberellin (GA) biosynthesis and the mechanism whereby GA homeostasis is maintained in plants, we have investigated the degree to which the enzyme GA 3-oxidase (GA3ox) limits the formation of bioactive GAs in elongating shoots of hybrid aspen (Populus tremula x Populus tremuloides). We describe the cloning of a hybrid aspen GA3ox and its functional characterization, which confirmed that it has 3beta-hydroxylation activity and more efficiently converts GA9 to GA4 than GA20 to GA1. To complement previous studies, in which transgenic GA 20-oxidase (GA20ox) overexpressers were found to produce 20-fold higher bioactive GA levels and subsequently grew faster than wild-type plants, we overexpressed an Arabidopsis GA3ox in hybrid aspen. The generated GA3ox overexpresser lines had increased 3beta-hydroxylation activity but exhibited no major changes in morphology. The nearly unaltered growth pattern was associated with relatively small changes in GA1 and GA4 levels, although tissue-dependent differences were observed. The absence of increases in bioactive GA levels did not appear to be due to feedback or feed-forward regulation of dioxygenase transcripts, according to semiquantitative reverse transcription polymerase chain reaction analysis of PttGA20ox1, PttGA3ox1, and two putative PttGA2ox genes. We conclude that 20-oxidation is the limiting step, rather than 3beta-hydroxylation, in the formation of GA1 and GA4 in elongating shoots of hybrid aspen, and that ectopic GA3ox expression alone cannot increase the flux toward bioactive GAs. Finally, several lines of evidence now suggest that GA4 has a more pivotal role in the tree hybrid aspen than previously believed.

  16. Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery

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    Zhang Gang; Jaana Luoranen; Heikki Smolander

    2007-01-01

    In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus,frost hardening is usually delayed. To solve this problem, We used a three-week period of short-day (SD) treatment between late July and mid-August. During autumn after frost exposure,frost hardiness (FH) Was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore,the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.

  17. Hybrid poplar plantations are suitable habitat for reintroduced forest herbs with conservation status.

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    Boothroyd-Roberts, Kathleen; Gagnon, Daniel; Truax, Benoit

    2013-01-01

    Plantations of fast-growing tree species may be of use in conservation by accelerating the restoration of forest habitat on abandoned farmland and increasing connectivity in fragmented landscapes. The objective of this study was to determine if hybrid poplar plantations can be suitable habitats for the reintroduction of native forest plant species and, if so, which abiotic factors predict successful reintroduction. Four species of forest herb species (Trillium grandiflorum, Sanguinaria canadensis, Maianthemum racemosum, Asarum canadense), of which three have legal conservation status, were transplanted into experimental plantations of two hybrid poplar clones and nearby second-growth woodlots at six sites in southern Quebec, Canada. The transplanted individuals were protected from deer browsing with exclusion cages. After two years, the plant responses of all four species were stable or increased over two years in both types of hybrid poplar plantations. Sanguinaria showed a better response in the plantations than in the woodlots, preferring the rich post-agricultural soils of the plantations with low C:N ratios. Asarum and Maianthemum showed no significant difference between stand types, while Trillium grew better in the woodlots than in the plantations. Much of the variability in the response of the latter three species was unexplained by the measured environmental variables. These results suggest that certain forest herb species can be reintroduced as juvenile plants into plantations, knowing that their spontaneous recolonization is often limited by dispersal and/or seedling establishment. Plantations could also contribute to the conservation of biodiversity by providing an environment for the cultivation of forest herb species as an alternative to their destructive harvest from natural populations.

  18. Tree age-dependent changes in photosynthetic and respiratory CO2 exchange in leaves of micropropagated diploid, triploid and hybrid aspen.

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    Pärnik, Tiit; Ivanova, Hiie; Keerberg, Olav; Vardja, Rael; Niinemets, Ulo

    2014-06-01

    The growth rate of triploid European aspen (Populus tremula L.) and hybrid aspen (P. tremula × Populus tremuloides Michx.) significantly exceeds that of diploid aspen, but the underlying physiological controls of the superior growth rates of these genotypes are not known. We tested the hypothesis that the superior growth rate of triploid and hybrid aspen reflects their greater net photosynthesis rate. Micropropagated clonal plants varying in age from 2.5 to 19 months were used to investigate the ploidy and plant age interaction. The quantum yield of net CO2 fixation (Φ) in leaves of young 2.5-month-old hybrid aspen was lower than that of diploid and triploid trees. However, Φ in 19-month-old hybrid aspen was equal to that in triploid aspen and higher than that in diploid aspen. Φ and the rate of light-saturated net photosynthesis (ANS) increased with plant age, largely due to higher leaf dry mass per unit area in older plants. ANS in leaves of 19-month-old trees was highest in hybrid, medium in triploid and lowest in diploid aspen. Light-saturated photosynthesis had a broad temperature optimum between 20 and 35 °C. Rate of respiration in the dark (RDS) did not vary among the genotypes in 2.5-month-old plants, and the shape of the temperature response was also similar. RDS increased with plant age, but RDS was still not significantly different among the leaves of 19-month-old diploid and triploid aspen, but it was significantly lower in leaves of 19-month-old hybrid plants. The initial differences in the growth of plants with different ploidy were minor up to the age of 19 months, but during the next 2 years, the growth rate of hybrid aspen exceeded that of triploid plants by 2.7 times and of diploid plants by five times, in line with differences in ANS of 19-month-old plants of these species. It is suggested that differences in photosynthesis and growth became more pronounced with tree aging, indicating that ontogeny plays a key role in the expression of

  19. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.

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    Niinemets, Ülo; Sun, Zhihong

    2015-02-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol(-1) or elevated [CO2] of 780 μmol mol(-1). The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size.

  20. Circadian patterns of xylem sap properties and their covariation with plant hydraulic traits in hybrid aspen.

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    Meitern, Annika; Õunapuu-Pikas, Eele; Sellin, Arne

    2017-06-01

    Physiological processes taking place in plants are subject to diverse circadian patterns but some of them are poorly documented in natural conditions. The daily dynamics of physico-chemical properties of xylem sap and their covariation with tree hydraulic traits were investigated in hybrid aspen (Populus tremula L.×P. tremuloides Michx) in field conditions in order to clarify which environmental drivers govern the daily variation in these parameters. K(+) concentration ([K(+)]), electrical conductivity (σsap), osmolality (Osm) and pH of the xylem sap, as well as branch hydraulic traits, were measured in the field over 24-h cycles. All studied xylem sap properties and hydraulic characteristics including whole-branch (Kwb), leaf blade (Klb) and petiole hydraulic conductances (KP) showed clear daily dynamics. Air temperature (TA) and photosynthetic photon flux density (PPFD), but also water vapour pressure deficit (VPD) and relative humidity (RH), had significant impacts on KwbKlb, KP, [K(+)] and σsap. Osm varied only with light intensity, while KB varied depending on atmospheric evaporative demand expressed as TA, VPD or RH. Xylem sap pH depended inversely on soil water potential (ΨS) and during daylight also on VPD. Although soil water content was close to saturation during the study period, ΨS influenced also [K(+)] and σsap. The present study presents evidence of coupling between circadian patterns of xylem sap properties and plant hydraulic conductance providing adequate water supply to foliage under environmental conditions characterised by diurnal variation. Copyright © 2017 Elsevier GmbH. All rights reserved.

  1. Evolution, three-dimensional model and localization of truncated hemoglobin PttTrHb of hybrid aspen.

    Science.gov (United States)

    Dumont, Estelle; Jokipii-Lukkari, Soile; Parkash, Vimal; Vuosku, Jaana; Sundström, Robin; Nymalm, Yvonne; Sutela, Suvi; Taskinen, Katariina; Kallio, Pauli T; Salminen, Tiina A; Häggman, Hely

    2014-01-01

    Thus far, research on plant hemoglobins (Hbs) has mainly concentrated on symbiotic and non-symbiotic Hbs, and information on truncated Hbs (TrHbs) is scarce. The aim of this study was to examine the origin, structure and localization of the truncated Hb (PttTrHb) of hybrid aspen (Populus tremula L. × tremuloides Michx.), the model system of tree biology. Additionally, we studied the PttTrHb expression in relation to non-symbiotic class1 Hb gene (PttHb1) using RNAi-silenced hybrid aspen lines. Both the phylogenetic analysis and the three-dimensional (3D) model of PttTrHb supported the view that plant TrHbs evolved vertically from a bacterial TrHb. The 3D model suggested that PttTrHb adopts a 2-on-2 sandwich of α-helices and has a Bacillus subtilis -like ligand-binding pocket in which E11Gln and B10Tyr form hydrogen bonds to a ligand. However, due to differences in tunnel cavity and gate residue (E7Ala), it might not show similar ligand-binding kinetics as in Bs-HbO (E7Thr). The immunolocalization showed that PttTrHb protein was present in roots, stems as well as leaves of in vitro -grown hybrid aspens. In mature organs, PttTrHb was predominantly found in the vascular bundles and specifically at the site of lateral root formation, overlapping consistently with areas of nitric oxide (NO) production in plants. Furthermore, the NO donor sodium nitroprusside treatment increased the amount of PttTrHb in stems. The observed PttTrHb localization suggests that PttTrHb plays a role in the NO metabolism.

  2. Assessing a Bayesian Approach for Detecting Exotic Hybrids between Plantation and Native Eucalypts

    Directory of Open Access Journals (Sweden)

    Matthew J. Larcombe

    2014-01-01

    Full Text Available Eucalyptus globulus is grown extensively in plantations outside its native range in Australia. Concerns have been raised that the species may pose a genetic risk to native eucalypt species through hybridisation and introgression. Methods for identifying hybrids are needed to enable assessment and management of this genetic risk. This paper assesses the efficiency of a Bayesian approach for identifying hybrids between the plantation species E. globulus and E. nitens and four at-risk native eucalypts. Range-wide DNA samples of E. camaldulensis, E. cypellocarpa, E. globulus, E. nitens, E. ovata and E. viminalis, and pedigreed and putative hybrids (n = 606, were genotyped with 10 microsatellite loci. Using a two-way simulation analysis (two species in the model at a time, the accuracy of identification was 98% for first and 93% for second generation hybrids. However, the accuracy of identifying simulated backcross hybrids was lower (74%. A six-way analysis (all species in the model together showed that as the number of species increases the accuracy of hybrid identification decreases. Despite some difficulties identifying backcrosses, the two-way Bayesian modelling approach was highly effective at identifying F1s, which, in the context of E. globulus plantations, are the primary management concern.

  3. Aspen Delineation - Aspen Delineation Project [ds362

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands, where aspen assessment data was gathered. Aspen assessment information corresponding to this polygon layer can...

  4. Short day-mediated cessation of growth requires the downregulation of AINTEGUMENTALIKE1 transcription factor in hybrid aspen.

    Directory of Open Access Journals (Sweden)

    Anna Karlberg

    2011-11-01

    Full Text Available Day length is a key environmental cue regulating the timing of major developmental transitions in plants. For example, in perennial plants such as the long-lived trees of the boreal forest, exposure to short days (SD leads to the termination of meristem activity and bud set (referred to as growth cessation. The mechanism underlying SD-mediated induction of growth cessation is poorly understood. Here we show that the AIL1-AIL4 (AINTEGUMENTALIKE transcription factors of the AP2 family are the downstream targets of the SD signal in the regulation of growth cessation response in hybrid aspen trees. AIL1 is expressed in the shoot apical meristem and leaf primordia, and exposure to SD signal downregulates AIL1 expression. Downregulation of AIL gene expression by SDs is altered in transgenic hybrid aspen plants that are defective in SD perception and/or response, e.g. PHYA or FT overexpressors. Importantly, SD-mediated regulation of growth cessation response is also affected by overexpression or downregulation of AIL gene expression. AIL1 protein can interact with the promoter of the key cell cycle genes, e.g. CYCD3.2, and downregulation of the expression of D-type cyclins after SD treatment is prevented by AIL1 overexpression. These data reveal that execution of SD-mediated growth cessation response requires the downregulation of AIL gene expression. Thus, while early acting components like PHYA and the CO/FT regulon are conserved in day-length regulation of flowering time and growth cessation between annual and perennial plants, signaling pathways downstream of SD perception diverge, with AIL transcription factors being novel targets of the CO/FT regulon connecting the perception of SD signal to the regulation of meristem activity.

  5. Climate change at northern latitudes: rising atmospheric humidity decreases transpiration, N-uptake and growth rate of hybrid aspen.

    Directory of Open Access Journals (Sweden)

    Arvo Tullus

    Full Text Available At northern latitudes a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. We studied several growth and functional traits of hybrid aspen (Populus tremula L.×P. tremuloides Michx. in response to elevated atmospheric humidity (on average 7% over the ambient level in a free air experimental facility during three growing seasons (2008-2010 in Estonia, which represents northern temperate climate (boreo-nemoral zone. Data were collected from three humidified (H and three control (C plots, and analysed using nested linear models. Elevated air humidity significantly reduced height, stem diameter and stem volume increments and transpiration of the trees whereas these effects remained highly significant also after considering the side effects from soil-related confounders within the 2.7 ha study area. Tree leaves were smaller, lighter and had lower leaf mass per area (LMA in H plots. The magnitude and significance of the humidity treatment effect--inhibition of above-ground growth rate--was more pronounced in larger trees. The lower growth rate in the humidified plots can be partly explained by a decrease in transpiration-driven mass flow of NO(3 (- in soil, resulting in a significant reduction in the measured uptake of N to foliage in the H plots. The results suggest that the potential growth improvement of fast-growing trees like aspens, due to increasing temperature and atmospheric CO(2 concentration, might be smaller than expected at high latitudes if a rise in atmospheric humidity simultaneously takes place.

  6. Carbon Sequestration Potential in Aboveground Biomass of Hybrid Eucalyptus Plantation Forest

    Directory of Open Access Journals (Sweden)

    Siti Latifah

    2013-04-01

    Full Text Available Forests are a significant part of the global carbon cycle. Forests sequester carbon by conducting photosynthesis, which is the process of converting light energy to chemical energy and storing it in the chemical bonds of sugar. Carbon sequestration through forestry has the potential to play a significant role in ameliorating global environmental problems such as atmospheric accumulation of GHG's and climate change.  The present investigation was carried out to determine carbon sequestration potential of hybrid Eucalyptus. This study was conducted primarily to develop a prediction model of carbon storage capacity for plantation forest of hybrid Eucalyptus in Aek Nauli, Simalungun District, North Sumatera. Models were tested and assessed for statistical validity and accuracy in predicting biomass and carbon, based on determination coefficient (R and correlation coefficient (r, aggregative deviation percentage (AgD, and the average deviation percentage (AvD. The best general model to estimate the biomass of hybrid Eucalyptus was Y = 1351,09x^0,876. e^(0,094.  Results showed that hybrid Eucalyptus had an average above-ground biomass in year 0 (the land without the eucalyptus trees up to year 3 as large as 1.36, 11.56, 43.18, and 63.84 t ha. The carbon content of hybrid Eucalyptus were 0.61, 5.2, 19.43 t^(-1, and 28,73  t^(-1 C ha while the carbon sequestration potential were 2.23, 19.08, 71.31, and 105.43 t^(-1 CO  ha^(-1 respectively.Keywords: biomass, carbon stock, model, hybrid Eucalyptus, plantation forest

  7. Transgenic hybrid aspen trees with increased gibberellin (GA) concentrations suggest that GA acts in parallel with FLOWERING LOCUS T2 to control shoot elongation.

    Science.gov (United States)

    Eriksson, Maria E; Hoffman, Daniel; Kaduk, Mateusz; Mauriat, Mélanie; Moritz, Thomas

    2015-02-01

    Bioactive gibberellins (GAs) have been implicated in short day (SD)-induced growth cessation in Populus, because exogenous applications of bioactive GAs to hybrid aspens (Populus tremula × tremuloides) under SD conditions delay growth cessation. However, this effect diminishes with time, suggesting that plants may cease growth following exposure to SDs due to a reduction in sensitivity to GAs. In order to validate and further explore the role of GAs in growth cessation, we perturbed GA biosynthesis or signalling in hybrid aspen plants by overexpressing AtGA20ox1, AtGA2ox2 and PttGID1.3 (encoding GA biosynthesis enzymes and a GA receptor). We found trees with elevated concentrations of bioactive GA, due to overexpression of AtGA20ox1, continued to grow in SD conditions and were insensitive to the level of FLOWERING LOCUS T2 (FT2) expression. As transgenic plants overexpressing the PttGID1.3 GA receptor responded in a wild-type (WT) manner to SD conditions, this insensitivity did not result from limited receptor availability. As high concentrations of bioactive GA during SD conditions were sufficient to sustain shoot elongation growth in hybrid aspen trees, independent of FT2 expression levels, we conclude elongation growth in trees is regulated by both GA- and long day-responsive pathways, similar to the regulation of flowering in Arabidopsis thaliana.

  8. Co-effect of increased humidity and meteorological conditions on greenhouse gas fluxes in a young hybrid aspen forest

    Science.gov (United States)

    Hansen, Raili; Mander, Ülo; Kupper, Priit; Soosaar, Kaido; Maddison, Martin; Sõber, Jaak; Lõhmus, Krista

    2014-05-01

    Due to the climate change, higher precipitation and an increase in air humidity is expected in northern Europe in the near future (IPCC 2007). There are some studies about irrigation, elevated CO2 and O3 etc., but still we have too little knowledge about the humidity effect on the deciduous forest ecosystem. In 2006 a free-air humidity manipulation (FAHM) facility was established in Estonia and in 2008 we started to artificially increase the air humidity in young hybrid aspen (Populus tremula L. x P. tremuloides Michx.) forest trials on an Endogleyic Planosol of former arable land. Air humidity was raised on average about 7% compared to ambient condition (Tullus et al., 2012). We measured the carbon dioxide, methane and nitrous oxide fluxes from the FAHM system using closed static chamber and gas-chromatograph techniques from July 2009 to November 2012 during snow free periods. Flux measurements were done once a month in three humidification (h) plots and in three control (c) plots. We monitored soil temperature, soil water potential (SWP), precipitation and relative humidity. The vegetation period was rainy in 2009, droughty in 2010 and 2011 (according to SWP the drought was severe in 2011) and cold in 2012. Soil respiration was the lowest in 2011 both in c and h plots; however it was significantly higher in h. Most of the time the soil was a sink for methane, but less CH4 was oxidized in the soil of h plots. Emission of N2O did not have good correlation with air humidity, although one could observe a clear tendency of bigger N2O fluxes when soil was continuously water-saturated. Expectedly, soil respiration had strong positive correlations with soil temperature and CH4 emission demonstrated strong positive correlation with SWP. Hence, interaction of humidification and precipitation affected greenhouse gas fluxes. IPCC, Climate Change 2007: The Physical Science Basis. Cambridge University Press, Cambridge. 2007. Tullus A, Kupper P, Sellin A, Parts L, Sõber J

  9. Comparing growth and fine root distribution in monocultures and mixed plantations of hybrid poplar and spruce

    Institute of Scientific and Technical Information of China (English)

    Lahcen Benomar; Annie DesRochers; Guy R.Larocque

    2013-01-01

    Disease prevention,biodiversity,productivity improvement and ecological considerations are all factors that contribute to increasing interest in mixed plantations.The objective of this study was to evaluate early growth and productivity of two hybrid poplar clones,P.balsamifera x trichocarpa (PBT) and P.maximowiczii x balsamifera (PMB),one improved family of Norway spruce (Picea glauca (PA)) and one improved family of white spruce (Picea abies (PG)) growing under different spacings in monocultures and mixed plots.The plantations were established in 2003 in Abitibi-Témiscamingue,Quebec,Canada,in a split plot design with spacing as the whole plot factor (1 × 1 m,3 × 3 m and 5 × 5 m) and mixture treatments as subplot factor (pure:PBT,PMB,PA and PG,and 1:1 mixture PBT:PA,PBT:PG,PMB:PA and PMB:PG).Results showed a beneficial effect of the hybrid poplar-spruce mixture on diameter growth for hybrid poplar clones,but not for the 5 × 5 m spacing because of the relatively young age of the plantations.Diameter growth of the spruces decreased in mixed plantings in the 1 × 1 m,while their height growth increased,resulting in similar aboveground biomass per tree across treatments.Because of the large size differences between spruces and poplars,aboveground biomass in the mixed plantings was generally less than that in pure poplar plots.Leaf nitrogen concentration for the two spruce families and hybrid poplar clone PMB was greater in mixed plots than in monocultures,while leaf nitrogen concentration of clone PBT was similar among mixture treatments.Because of its faster growth rate and greater soil resources demands,clone PMB was the only one showing an increase in leaf N with increased spacing between trees.Fine roots density was greater for both hybrid poplars than spruces.The vertical distribution of fine roots was insensitive to mixture treatment.

  10. Exploring the Role of Plant Genetics to Enhance Soil Carbon Sequestration in Hybrid Poplar Plantations

    Science.gov (United States)

    Wullschleger, S. D.; Garten, C. T.; Classen, A. T.

    2008-12-01

    Atmospheric CO2 concentrations have increased in recent decades and are projected to increase even further during the coming century. These projections have prompted scientists and policy-makers to consider how plants and soils can be used to stabilize CO2 concentrations. Although storing carbon in terrestrial ecosystems represents an attractive near-term option for mitigating rising atmospheric CO2 concentrations, enhancing the sequestration potential of managed systems will require advancements in understanding the fundamental mechanisms that control rates of carbon transfer and turnover in plants and soils. To address this challenge, a mathematical model was constructed to evaluate how changes in particular plant traits and management practices could affect soil carbon storage beneath hybrid poplar (Populus) plantations. The model was built from four sub-models that describe aboveground biomass, root biomass, soil carbon dynamics, and soil nitrogen transformations for trees growing throughout a user-defined rotation. Simulations could be run over one or multiple rotations. A sensitivity analysis of the model indicated changes in soil carbon storage were affected by variables that could be linked to hybrid poplar traits like rates of aboveground production, partitioning of carbon to coarse and fine roots, and rates of root decomposition. A higher ratio of belowground to aboveground production was especially important and correlated directly with increased soil carbon storage. Faster decomposition rates for coarse and fine dead roots resulted in a greater loss of carbon to the atmosphere as CO2 and less residual organic carbon for transfer to the fast soil carbon pool. Hence, changes in root chemistry that prolonged dead root decomposition rates, a trait that is under potential genetic control, were predicted to increase soil carbon storage via higher soil carbon inputs. Nitrogen limitation of both aboveground biomass production and soil carbon sequestration was

  11. Biomass and Volume Yield in Mature Hybrid Poplar Plantations on Temperate Abandoned Farmland

    Directory of Open Access Journals (Sweden)

    Benoit Truax

    2014-12-01

    Full Text Available In this study, we developed clone-specific allometric relationships, with the objective of calculating volume and biomass production after 13 years in 8 poplar plantations, located across an environmental gradient, and composed of 5 unrelated hybrid poplar clones. Allometry was found to be very similar for clones MxB-915311, NxM-3729 and DNxM-915508, all having P. maximoviczii parentage. Clones DxN-3570 and TxD-3230 also had a similar allometry; for a given DBH they have a lower stem volume, stem biomass and branch biomass than P. maximoviczii hybrids. Strong Site × Clone interactions were observed for volume and woody biomass growth, with DxN and TxD hybrids only productive on low elevation fertile sites, whereas P. maximovizcii hybrids were also very productive on higher elevation sites with moderate to high soil fertility. At the site level (5 clones mean, yield reached 27.5 and 22.7 m3/ha/yr. on the two best sites (high fertility and low elevation, confirming the great potential of southern Québec (Canada for poplar culture. The productivity gap between the most and least productive sites has widened from year 8 to year 13, highlighting the need for high quality abandoned farmland site selection in terms of climate and soil fertility. Although clone selection could optimize yield across the studied environmental gradient, it cannot fully compensate for inadequate site selection.

  12. The role of phytochrome A and gibberellins in growth under long and short day conditions: Studies in hybrid aspen

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, M.E. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

    2000-07-01

    This thesis addresses questions concerning the regulation of growth and, specifically, the cessation of growth in response to short days in deciduous tree species. The model tree used in the studies was hybrid aspen (Populus tremula L. x P. tremuloides Michx.). We have exploited the possibility of transforming this species to modulate the level of expression of target genes using over-expression and antisense techniques. The target genes in the studies were the photoreceptor phytochrome A (phyA) and gibberellin 20-oxidase (GA 20-oxidase), the latter being a highly regulated enzyme involved in the biosynthesis of gibberellins (GAs). The photoreceptor phyA has been implicated in photoperiodic regulation of growth, while GAs may regulate the physiological response further downstream. The endogenous expression of these genes has been investigated in parallel with studies of various plants with ectopic and reduced levels of expression. The main focus has been on the early stages of induction of growth cessation and its physiological and molecular mechanisms. Studies of hybrid aspen plants with an increased or reduced expression of phyA, show this receptor to mediate the photoperiodic regulation of growth. Plants with ectopic expression could not stop growing despite drastically shortened photoperiods, while the antisense plants showed the reverse phenotype, with a higher sensitivity resulting in earlier cessation of growth. The role of GAs in growth inhibition was also addressed using plants with a reduction in GA levels. These plants showed early cessation of growth and dormancy, and thus an increased sensitivity toward daylength. Conversely, plants with increased rates of GA biosynthesis showed increased growth and stopped growing much later. Furthermore, increases in GA biosynthesis, resulting in high levels of GAs have a major impact on growth. Plants with high GA levels have increased elongation and diameter growth, due to higher rates of cell production in the

  13. Bisphosphonate inhibitors reveal a large elasticity of plastidic isoprenoid synthesis pathway in isoprene-emitting hybrid aspen.

    Science.gov (United States)

    Rasulov, Bahtijor; Talts, Eero; Kännaste, Astrid; Niinemets, Ülo

    2015-06-01

    Recently, a feedback inhibition of the chloroplastic 1-deoxy-D-xylulose 5-phosphate (DXP)/2-C-methyl-D-erythritol 4-phosphate (MEP) pathway of isoprenoid synthesis by end products dimethylallyl diphosphate (DMADP) and isopentenyl diphosphate (IDP) was postulated, but the extent to which DMADP and IDP can build up is not known. We used bisphosphonate inhibitors, alendronate and zoledronate, that inhibit the consumption of DMADP and IDP by prenyltransferases to gain insight into the extent of end product accumulation and possible feedback inhibition in isoprene-emitting hybrid aspen (Populus tremula × Populus tremuloides). A kinetic method based on dark release of isoprene emission at the expense of substrate pools accumulated in light was used to estimate the in vivo pool sizes of DMADP and upstream metabolites. Feeding with fosmidomycin, an inhibitor of DXP reductoisomerase, alone or in combination with bisphosphonates was used to inhibit carbon input into DXP/MEP pathway or both input and output. We observed a major increase in pathway intermediates, 3- to 4-fold, upstream of DMADP in bisphosphonate-inhibited leaves, but the DMADP pool was enhanced much less, 1.3- to 1.5-fold. In combined fosmidomycin/bisphosphonate treatment, pathway intermediates accumulated, reflecting cytosolic flux of intermediates that can be important under strong metabolic pull in physiological conditions. The data suggested that metabolites accumulated upstream of DMADP consist of phosphorylated intermediates and IDP. Slow conversion of the huge pools of intermediates to DMADP was limited by reductive energy supply. These data indicate that the DXP/MEP pathway is extremely elastic, and the presence of a significant pool of phosphorylated intermediates provides an important valve for fine tuning the pathway flux.

  14. Aspen Trees.

    Science.gov (United States)

    Canfield, Elaine

    2002-01-01

    Describes a fifth-grade art activity that offers a new approach to creating pictures of Aspen trees. Explains that the students learned about art concepts, such as line and balance, in this lesson. Discusses the process in detail for creating the pictures. (CMK)

  15. Breeding Strategy of Acacia Hybrid (Acacia mangium × A. auriculiformis to Increase Forest Plantation Productivity in Indonesia

    Directory of Open Access Journals (Sweden)

    Sri Sunarti

    2013-08-01

    Full Text Available Acacia hybrid (Acacia mangium× A.auriculiformis shows better growth and wood properties, and tolerance to pest and disease. Currently, acacia hybrid breeding strategy was developed through naturally hybrid selected from trees grown in plantation. However, mass propagation of acacia hybrid using such kind of strategy was not satisfied due to ageing effect. This study was aimed to develop a new acacia hybrid breeding strategy using controlled pollination hybridization technique. The strategy was developed through a series of research: flowering, crossing, hybrid identification, clone multiplication, and clonal test. The results of study showed that the series of research for developing acacia hybrid breeding strategy was achieved. Flowering time synchronization provided a high probability for the success of controlled pollination hybridization. Leaves taxonomy at seedling stage revealed to be an efective way to identify acacia hybrid with acuracy of 92.2%. The acacia hybrid was succesfully propagated using shoot cutting at rate of 78.1%. The best selected clones of acacia hybrid outperformed in height growth at rates of 17.28% over to superior pure parents, which is equivalent to the estimated stand productivity at around 48 m3 ha-1 y-1. The series of research provided a new effective and efficient breeding strategy for acacia hybrid.Keywords: Acacia auriculiformis,  Acacia mangium, acacia hybrid, controlled pollination, breeding strategyDOI: 10.7226/jtfm.19.2.128

  16. A genome-wide screen for ethylene-induced ethylene response factors (ERFs) in hybrid aspen stem identifies ERF genes that modify stem growth and wood properties.

    Science.gov (United States)

    Vahala, Jorma; Felten, Judith; Love, Jonathan; Gorzsás, András; Gerber, Lorenz; Lamminmäki, Airi; Kangasjärvi, Jaakko; Sundberg, Björn

    2013-10-01

    Ethylene Response Factors (ERFs) are a large family of transcription factors that mediate responses to ethylene. Ethylene affects many aspects of wood development and is involved in tension wood formation. Thus ERFs could be key players connecting ethylene action to wood development. We identified 170 gene models encoding ERFs in the Populus trichocarpa genome. The transcriptional responses of ERF genes to ethylene treatments were determined in stem tissues of hybrid aspen (Populus tremula × tremuloides) by qPCR. Selected ethylene-responsive ERFs were overexpressed in wood-forming tissues and characterized for growth and wood chemotypes by FT-IR. Fifty ERFs in Populus showed more than five-fold increased transcript accumulation in response to ethylene treatments. Twenty-six ERFs were selected for further analyses. A majority of these were induced during tension wood formation. Overexpression of ERFs 18, 21, 30, 85 and 139 in wood-forming tissues of hybrid aspen modified the wood chemotype. Moreover, overexpression of ERF139 caused a dwarf-phenotype with altered wood development, and overexpression of ERF18, 34 and 35 slightly increased stem diameter. We identified ethylene-induced ERFs that respond to tension wood formation, and modify wood formation when overexpressed. This provides support for their role in ethylene-mediated regulation of wood development.

  17. Aspen Characteristics - Aspen Delineation Project [ds361

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Lake Tahoe Basin Management Unit (Placer and...

  18. Establishment of Alleycropped Hybrid Aspen “Crandon” in Central Iowa, USA: Effects of Topographic Position and Fertilizer Rate on Aboveground Biomass Production and Allocation

    Directory of Open Access Journals (Sweden)

    Richard B. Hall

    2013-07-01

    Full Text Available Hybrid poplars have demonstrated high productivity as short rotation woody crops (SRWC in the Midwest USA, and the hybrid aspen “Crandon” (Populus alba L. × P. grandidenta Michx. has exhibited particularly promising yields on marginal lands. However, a key obstacle for wider deployment is the lack of economic returns early in the rotation. Alleycropping has the potential to address this issue, especially when paired with crops such as winter triticale which complete their growth cycle early in the summer and therefore are expected to exert minimal competition on establishing trees. In addition, well-placed fertilizer in low rates at planting has the potential to improve tree establishment and shorten the rotation, which is also economically desirable. To test the potential productivity of “Crandon” alleycropped with winter triticale, plots were established on five topographic positions with four different rates of fertilizer placed in the planting hole. Trees were then harvested from the plots after each of the first three growing seasons. Fertilization resulted in significant increases in branch, stem, and total aboveground biomass across all years, whereas the effects of topographic position varied by year. Allocation between branches and stems was found to be primarily a function of total aboveground biomass.

  19. Increasing the productivity of biomass plantations of Populus species and hybrids in the Pacific Northwest. Final report, September 14, 1981--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    DeBell, D.S.; Harrington, C.A.; Clendenen, G.W. [USDA Forest Service, Olympia, WA (United States)] [and others

    1997-08-01

    This final report represents the culmination of eight years of biological research devoted to increasing the productivity of short rotation plantations of Populus trichocarpa and Populus hybrids in the Pacific Northwest. Studies described herein provide an understanding of tree growth, stand development and biomass yield at various spacings, and how patterns thereof differ by Populus clone in monoclonal and polyclonal plantings. Also included is some information about factors related to wind damage in Populus plantings, use of leaf size as a predictor of growth potential, and approaches for estimating tree and stand biomass and biomass growth. The work was accomplished in three research plantations, all established cooperatively with the Washington State Department of Natural Resources (DNR) and located at the DNR Tree Improvement Center near Olympia. The first plantation was established in Spring 1986 to evaluate the highly touted {open_quotes}woodgrass{close_quotes} concept and compare it with more conventional short-rotation management regimes, using two Populus hybrid clones planted at five spacings. Besides providing scientific data to resolve the politicized {open_quotes}wood-grass{close_quotes} dispute, this plantation has furnished excellent data on stand dynamics and woody biomass yield. A second plantation was established at the same time; groups of trees therein received two levels of irrigation and different amounts of four fertilizer amendments, resulting in microsites with diverse moisture and nutrient conditions.

  20. Understanding the role of the cytoskeleton in wood formation in angiosperm trees: hybrid aspen (Populus tremula x P. tremuloides) as a model species

    Energy Technology Data Exchange (ETDEWEB)

    Chaffey, N.; Barlow, P. [Bristol Univ., Dept. of Agricultural Sciences, Long Ashton, (United Kingdom); Sundberg, B. [Swedish Univ. of Agricultural Sciences, Dept. of Forest Genetics and Plant Physiology, Umea (Sweden)

    2002-03-01

    The involvement of microfilaments (MFs) and microtubules (MTs) in the development of the radial and axial components of secondary wood in hybrid aspen (Populus tremula X P. tremuloides) was studied by indirect immunofluorescent localization techniques in order to elucidate a consensus view of the roles of the cytoskeleton during wood formation in angiosperm trees. Early and late vessel elements, axial parenchyma, normal-wood fibres and contact and isolation cells were included in addition to cambial cells. Microfilaments were found to be rare in cambial cells, but were abundant and axially arranged in their derivatives once cell elongation begun. Microtubules were randomly oriented in ray and fusiform cells of the cambial zone. Ellipses of microfilaments were associated with pit development in fiber cells and isolation ray cells. Rings of localized microtubules and microfilaments were associated with developing inter-vessel bordered pits and vessel-contact ray cell contact pits. Although only microtubules were seen in the periphery of the perforation plate of vessel elements, a prominent meshwork of microfilaments overlaid the perforation plate itself. These observations indicate that there are corresponding subcellular control points whose manipulation could lead to the development of 'designer wood'. However, such development would require a better understanding of the physiological basis for the behaviour of microtubule and microfibre cytoskeletons during wood formation. 44 refs., 6 figs.

  1. Assessing aspen using remote sensing

    Science.gov (United States)

    Randy Hamilton; Kevin Megown; Jeff DiBenedetto; Dale Bartos; Anne Mileck

    2009-01-01

    Large areas of aspen (Populus tremuloides) have disappeared and continue to disappear from western forests due to successional decline and sudden aspen decline (SAD). This loss of aspen ecosystems negatively impacts watersheds, wildlife, plants, and recreation. Much can still be done to restore aspen if timely and appropriate action is taken. However, land managers...

  2. Effect of Alnus glutinosa on hybrid populus growth and soil nitrogen concentration in a mixed plantation

    Science.gov (United States)

    Jeffrey O. Dawson; Edward A. Hansen

    1983-01-01

    Height growth of hybrid Populusand soil nitrogen concentration around Alnus glutinosa stems differed significantly both spatially and with the Alnus/Populus mixture in a short-rotation intensively cultured mixed planting. Populus height growth comparable to that obtained from optimal rates of...

  3. Bio energy production in birch and hybrid aspen after addition of residue based fertilizers - establishment of fertilization trials; Bioenergiproduktion hos bjoerk och hybridasp vid tillfoersel av restproduktbaserade goedselmedel - etablering av goedslingsfoersoek

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar (EkoBalans Fenix AB, Malmoe (Sweden))

    2009-03-15

    Sewage sludge and wood ashes could be used as fertilizers in order to increase forest tree production. In southern Sweden forest growth normally increases with approximately 10 % after ash recycling due to increased N and/or P availability. P is added with the ashes and the pH-increasing effect of the wood ash can lead to increased N net mineralization. Other positive effects of wood ash recycling are improved nutrient sustainability and less acid run-off water. Possible negative effects are heavy metal accumulation, if the content of one or more heavy metals of the recycled ash exceeds the heavy metal content of the harvested biomass, and nitrate leaching if the vegetation cannot take up nitrified N. It is important to evaluate the sustainability of fertilization systems based on residues such as sludge and wood ash. Wood ash does not contain N and the P concentration often is too low for the ashes to function as an NP fertilizer. Thus N and sometimes P must be added. Sludge is an interesting alternative. The main purpose of the project is to study sustainable production of forest bio energy in intensively cultivated birch and hybrid aspen stands. Another purpose is to establish experiments that can be used for long term studies and as demonstration objects. In the first few years the goal is to study the short term effects of residue based fertilization compared to conventional NPK fertilization on tree nutrient uptake, nutrient leaching, sustainability and economy. In the long term the goal is to design appropriate fertilization strategies in a residue based fertilization system for the intensive cultivation of birch and hybrid aspen without negative side effects such as large scale nutrient leaching. Four field experiments were established in 2008 and one additional experiment in hybrid aspen will be established in the spring of 2009. Elevated bud N and P concentrations after fertilization with both Ashes+N and NPK means good possibilities for future growth

  4. Shady Plantations

    DEFF Research Database (Denmark)

    Hastrup, Frida

    2011-01-01

    This article explores practices of protection played out in a coastal plantation in a village in Tamil Nadu. I argue that these practices are articulations of different but coexisting theorizations of shelter, and that the plantation can be seen as that which emerges at the intersections between...

  5. From the Aspen File.

    Science.gov (United States)

    Aspen Institute Quarterly, 1993

    1993-01-01

    Presents nine recommendations developed at the 1992 Policy Issue Forum of the Aspen Institute's Program on Policy Issues in Energy and Resources. The underlying theme is that the world is entering a new era of environmental policy formation. Issues a call for a national strategy for environmental management. (SLD)

  6. Nitrogen removal and its determinants in hybrid Populus clones for bioenergy plantations after two biennial rotations in two temperate sites in northern Italy

    Directory of Open Access Journals (Sweden)

    Paris P

    2015-10-01

    Full Text Available The sustainability of bioenergy coppice plantations is strongly affected by the Nitrogen (N balance, whose removal is very high due to the frequent harvest of large quantities of biomass composed of small-sized shoots. Poplar bioenergy coppice plantations could have a Nitrogen removal comparable to herbaceous crops. In this study, five hybrid poplar genotypes (“AF2”, “AF6”, “Monviso”, “83.148.041”, “I214” were compared for tree morphological traits related to yield, N removal in the harvested biomass and Nitrogen wood concentration (N% after two biennial coppice rotations in two experimental plantations located in northern Italy. N removal was primarily influenced by biomass production, and linear positive relationships between biomass yield and N removal were established. N removal also varied greatly among genotypes due to clonal differences in yield and in N%, in relation to significant differences among clones for their branching and sprouting habits. In the first rotation, branchiness was positively correlated to N% with a significant coefficient of determination (R2=0.813, while at the end of the second rotation it was also significantly correlated to the shoots per stool ratio (R2=0.804. “Monviso” and “83.148.041” were the clones showing the highest yield, but also a high N% associated to an high level of branchiness and shoots per stool ratio. Our results highlight that poplar genotype selection for sustainable N management should be aimed at genotypes with low wood N concentration, coupling high yield with low branching and sprouting habits as in the case of the clone “AF2”.

  7. Aspen Delineation - Klamath National Forest [ds370

    Data.gov (United States)

    California Department of Resources — The database represents polygons of aspen stands in the Klamath National Forest, Siskiyou County, California. The Klamath National Forest Region 5 Vegetation aspen...

  8. Aspen Delineation - Inyo National Forest [ds366

    Data.gov (United States)

    California Department of Resources — The database represents delineations of known aspen stands where aspen assessments were collected in the Inyo National Forest, Inyo County, California. The Inyo...

  9. Enhancement of production of eugenol and its glycosides in transgenic aspen plants via genetic engineering.

    OpenAIRE

    Koeduka, Takao; Suzuki, Shiro; Iijima, Yoko; Ohnishi, Toshiyuki; Suzuki, Hideyuki; Watanabe, Bunta; Shibata, Daisuke; Umezawa, Toshiaki; Pichersky, Eran; Hiratake, Jun

    2013-01-01

    Eugenol, a volatile phenylpropene found in many plant species, exhibits antibacterial and acaricidal activities. This study attempted to modify the production of eugenol and its glycosides by introducing petunia coniferyl alcohol acetyltransferase (PhCFAT) and eugenol synthase (PhEGS) into hybrid aspen. Gas chromatography analyses revealed that wild-type hybrid aspen produced small amount of eugenol in leaves. The heterologous overexpression of PhCFAT alone resulted in up to 7-fold higher eug...

  10. THE ASPEN CONTINUOUS PROGRESS PLAN.

    Science.gov (United States)

    MORNINGSTAR, NED

    THIS REPORT IS A DOCUMENTATION OF THE EFFORTS OF THE STAFF OF THE ASPEN ELEMENTARY SCHOOL, ASPEN, COLORADO, TO INDIVIDUALIZE THE INSTRUCTIONAL PROGRAM IN GRADES K-6. INVOLVED IN THIS WERE APPROXIMATELY 450 STUDENTS AND A STAFF OF 13 TEACHERS. THE INDIVIDUALIZATION OF INSTRUCTION WAS ACCOMPLISHED THROUGH THE MODIFICATION OF THE TEACHING-LEARNING…

  11. Energy sensitivity and variability analysis of Populus hybrid short-rotation plantations in northeastern United States. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bowersox, T.W.; Blankenhorn, P.R.

    1979-10-24

    Production of biomass by corn-like plantations has been demonstrated by a number of researchers. These forest analogs of agronomic cropping systems have the potential to yield substantially more biomass per unit area than traditional forests. Care is needed in choosing the appropriate sites, species, spacing, and harvesting strategies. Opportunities for increased yields have been suggested for fertilization and irrigation. Utilization of the biomass from these dense plantations for energy was the focus of this study. Although the amount of energy potential of the biomass is important, the energy output must be greater than the energy input for biomass to have a positive benefit to society. Further, in order to completely evaluate the net energy of the system it is necessary to examine the energy out-to-in ratios on the basis of usable energy (for example, usable heat, process steam and electricity), as well as all of the energies expended in producing, harvesting, transporting and processing the biomass. The objective of this study is to establish and analyze the energy inputs for selected management strategies in order to evaluate the sensitivity and variability of the energy inputs in the net energy analysis, and based on the net energy analysis to recommend a management strategy that minimizes energy inputs while maximizing biomass yield for short-rotation systems of Populus spp. in the northeastern United States.

  12. Influence of Climate on the Growth of Hybrid Poplar in Michigan

    Directory of Open Access Journals (Sweden)

    Sophan Chhin

    2010-11-01

    Full Text Available This study examined the influence of climate on cumulative and interannual growth patterns of 18 full-sib families of hybrid poplars (Populus × smithii Boivin derived from different geographical locations (state counties of natural stands of aspen parents (trembling aspen (Populus tremuloides Michx. and bigtooth aspen (Populus grandidentata Michx.. The hybrids were subsequently planted in 1982 in southern mid-Michigan at Michigan State University (MSU Sandhill Research Area. Cumulative measures of hybrid poplar productivity (diameter, height, basal area, and stem volume in 2009 (28 years since plantation establishment were related via correlation analysis to geographical distances and climatic variables (temperature and precipitation between parental county locations and between parental locations and the plantation site. Tree-ring analysis methods (dendrochronology were also used to quantify the influence of climate (i.e., mean temperature and total precipitation at monthly and 3-month seasonal scales on interannual basal area growth rates of hybrid poplars. Analyses of cumulative measures of growth indicated a maternal effect: full-sib families had higher productivity if they had a maternal parent originating from a state county that was close to or had higher temperature (annual and summer and summer precipitation than corresponding parameters of the planting site. Principal component analysis indicated that 17 of the 18 full-sib families shared a large amount of common growth variation. Dendrochronological analyses of interannual growth-climate relationships indicated that growth was mainly affected by the degree of late summer to fall moisture stress in both the current and previous growth season, and the degree of winter harshness.

  13. Aspen Delineation - Sequoia National Forest [ds378

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (SEQUOIA_NF_PTS) collected in aspen stands in the Cannell Meadows Ranger...

  14. Aspen Delineation - Plumas National Forest [ds374

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (PLUMAS_NF_PTS) collected in aspen stands in the Plumas National Forest,...

  15. Aspen Delineation - Lassen National Forest [ds372

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (LASSEN_NF_EAGLELAKE_PTS) collected in aspen stands in the in the Eagle...

  16. Aspen Delineation - Sierra State Parks [ds380

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (SIERRA_SP_PTS) collected in aspen stands on lands administered by the...

  17. 1990 sampling of treated aspen stands

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In mid-August, 1990, sampling of aspen stand exclosures were conducted at the National Elk Refuge. This sampling is part of a study to monitor aspen regeneration on...

  18. Using user models in Matlab® within the Aspen Plus® interface with an Excel® link

    Directory of Open Access Journals (Sweden)

    Javier Fontalvo Alzate

    2014-07-01

    Full Text Available Process intensification and new technologies require tools for process design that can be integrated into well-known simulation software, such as Aspen Plus®. Thus, unit operations that are not included in traditional Aspen Plus software packages can be simulated with Matlab® and integrated within the Aspen Plus interface. In this way, the user can take advantage of all of the tools of Aspen Plus, such as optimization, sensitivity analysis and cost estimation. This paper gives a detailed description of how to implement this integration. The interface between Matlab and Aspen Plus is accomplished by sending the relevant information from Aspen Plus to Excel, which feeds the information to a Matlab routine. Once the Matlab routine processes the information, it is returned to Excel and to Aspen Plus. This paper includes the Excel and Matlab template files so the reader can implement their own simulations. By applying the protocol described here, a hybrid distillation-vapor permeation system has been simulated as an example of the applications that can be implemented. For the hybrid system, the effect of membrane selectivity on membrane area and reboiler duty for the partial dehydration of ethanol is studied. Very high selectivities are not necessarily required for an optimum hybrid distillation and vapor permeation system.

  19. Biomass production in forest plantations used as raw material for industry and energy. Final report. Biomasseproduktion in forstlichen Plantagen fuer die Rohstoff- und Energiegewinnung. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, M.R.; Muhs, H.J.

    1986-10-01

    European aspen (Populus tremula), quaking aspen (Populus tremuloides), and their hybrids (hybrid aspen) are short-rotation, fast growing forest tree species, that apparently hold potential for biomass and energy production. Because of inherent difficulties in vegetative propagation in aspen, it has not been possible to propagate selected aspen and hybrid aspen tress on a large scale. Therefore, the aim of this project was to develop unconventional methods of vegetative propagation in aspen that can easily be adapted to nursery practices and are also cost-effective. Explants from buds, leaves, stems, and roots were cultured on a modified Woody Plant Medium for the purposes of microvegetative propagation. Protoplasts were also cultured for regenerative studies. Mainly the bud explants were employed for microvegetative propagation. A 2-step micropropagation method, which is commmercially feasible, has been developed for aspen. This method involves: (1) culture of bud explants on a medium for bud conditioning and microshoot proliferation, and (2) rooting of microshoots in peat-perlite mix. By employing this 2-step micropropagation method, several thousand plants have been regenerated from about 50 mature selected aspen and hybrid aspen trees ranging from 1 to 40 years of age. Following transfer to field conditions, tissue culture derived plants exhibited vigorous growth and attained a height of 1.5-2 meters in the first growing season. (orig.) With 23 refs., 1 tab., 20 figs.

  20. Aspen Characteristics - Plumas National Forest [ds373

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Plumas National Forest, Beckwourth Ranger District...

  1. Aspen Characteristics - Sierra State Parks [ds379

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands on lands administrated by the Sierra District, California...

  2. Aspen Characteristics - Klamath National Forest [ds369

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected with known aspen stands in the Klamath National Forest, Siskiyou County,...

  3. Aspen Characteristics - Sequoia National Forest [ds377

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Cannell Meadows Ranger District, Sequoia National...

  4. Aspen Delineation - El Dorado National Forest [ds364

    Data.gov (United States)

    California Department of Resources — The database represents delineations of known aspen stands, where aspen assessments were gathered in the Eldorado National Forest, Eldorado and Amador Counties,...

  5. Aspen Delineation - Klamath National Forest, EUI [ds368

    Data.gov (United States)

    California Department of Resources — The database represents delineations of known aspen stands where aspen assessments were collected in the Klamath National Forest, Siskiyou County, California. The...

  6. Aspen Notebook: Cable and Continuing Education.

    Science.gov (United States)

    Adler, Richard; Baer, Walter S.

    This is the first of a planned series of Aspen Notebooks on cable television (CATV). Part I reports on research conducted by the Aspen Workshop on Uses of the Cable. It describes the status of continuing education and the history of educational television and explores the prospects created by cable's development for extending access to continuing…

  7. Adapting ASPEN for Orbital Express

    Science.gov (United States)

    Chouinard, Caroline; Tran, Daniel; Jones, Grailing; Dang, Van; Knight, Russell

    2010-01-01

    By studying the Orbital Express mission, modeling the spacecraft and scenarios, and testing the system, a technique has been developed that uses recursive decomposition to represent procedural actions declaratively, schema-level uncertainty reasoning to make uncertainty reasoning tractable, and lightweight, natural language processing to automatically parse procedures to produce declarative models. Schema-level uncertainty reasoning has, at its core, the basic assumption that certain variables are uncertain, but not independent. Once any are known, then the others become known. This is important where a variable is uncertain for an action and many actions of the same type exist in the plan. For example, if the number of retries to purge pump lines was unknown (but bounded), and each attempt required a sub-plan, then, once the correct number of attempts required for a purge was known, it would likely be the same for all subsequent purges. This greatly reduces the space of plans that needs to be searched to ensure that all executions are feasible. To accommodate changing scenario procedures, each is ingested into a tabular format in temporal order, and a simple natural-language parser is used to read each step and to derive the impact of that step on memory, power, and communications. Then an ASPEN (Activity Scheduling and Planning Environment) model is produced based on this analysis. The model is tested and further changed by hand, if necessary, to reflect the actual procedure. This results in a great savings of time used for modeling procedures. Many processes that need to be modeled in ASPEN (a declarative system) are, in fact, procedural. ASPEN includes the ability to model activities in a hierarchical fashion, but this representation breaks down if there is a practically unbounded number of sub-activities and decomposition topologies. However, if recursive decomposition is allowed, HTN-like encodings are enabled to represent most procedural phenomena. For

  8. Aspen Characteristics - Lassen National Forest [ds371

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected in aspen stands in the in the Eagle Lake Ranger District, Lassen National...

  9. Enhancement of production of eugenol and its glycosides in transgenic aspen plants via genetic engineering.

    Science.gov (United States)

    Koeduka, Takao; Suzuki, Shiro; Iijima, Yoko; Ohnishi, Toshiyuki; Suzuki, Hideyuki; Watanabe, Bunta; Shibata, Daisuke; Umezawa, Toshiaki; Pichersky, Eran; Hiratake, Jun

    2013-06-21

    Eugenol, a volatile phenylpropene found in many plant species, exhibits antibacterial and acaricidal activities. This study attempted to modify the production of eugenol and its glycosides by introducing petunia coniferyl alcohol acetyltransferase (PhCFAT) and eugenol synthase (PhEGS) into hybrid aspen. Gas chromatography analyses revealed that wild-type hybrid aspen produced small amount of eugenol in leaves. The heterologous overexpression of PhCFAT alone resulted in up to 7-fold higher eugenol levels and up to 22-fold eugenol glycoside levels in leaves of transgenic aspen plants. The overexpression of PhEGS alone resulted in a subtle increase in either eugenol or eugenol glycosides, and the overexpression of both PhCFAT and PhEGS resulted in significant increases in the levels of both eugenol and eugenol glycosides which were nonetheless lower than the increases seen with overexpression of PhCFAT alone. On the other hand, overexpression of PhCFAT in transgenic Arabidopsis and tobacco did not cause any synthesis of eugenol. These results indicate that aspen leaves, but not Arabidopsis and tobacco leaves, have a partially active pathway to eugenol that is limited by the level of CFAT activity and thus the flux of this pathway can be increased by the introduction of a single heterologous gene.

  10. Aspen Delineation - Plumas National Forest, FRRD [ds376

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (PLUMAS_NF_FEATHERRIVER_PTS) collected in aspen stands in the Plumas...

  11. Fire regimes of quaking aspen in the Mountain West

    Science.gov (United States)

    Shinneman, Douglas J.; Baker, William L.; Rogers, Paul C.; Kulakowski, Dominik

    2013-01-01

    Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, and it is found throughout much of the Mountain West (MW) across a broad range of bioclimatic regions. Aspen typically regenerates asexually and prolifically after fire, and due to its seral status in many western conifer forests, aspen is often considered dependent upon disturbance for persistence. In many landscapes, historical evidence for post-fire aspen establishment is clear, and following extended fire-free periods senescing or declining aspen overstories sometimes lack adequate regeneration and are succeeding to conifers. However, aspen also forms relatively stable stands that contain little or no evidence of historical fire. In fact, aspen woodlands range from highly fire-dependent, seral communities to relatively stable, self-replacing, non-seral communities that do not require fire for persistence. Given the broad geographic distribution of aspen, fire regimes in these forests likely co-vary spatially with changing community composition, landscape setting, and climate, and temporally with land use and climate – but relatively few studies have explicitly focused on these important spatiotemporal variations. Here we reviewed the literature to summarize aspen fire regimes in the western US and highlight knowledge gaps. We found that only about one-fourth of the 46 research papers assessed for this review could be considered fire history studies (in which mean fire intervals were calculated), and all but one of these were based primarily on data from fire-scarred conifers. Nearly half of the studies reported at least some evidence of persistent aspen in the absence of fire. We also found that large portions of the MW have had little or no aspen fire history research. As a result of this review, we put forth a classification framework for aspen that is defined by key fire regime parameters (fire severity and probability), and that reflects underlying biophysical

  12. Basic tree-ring sample preparation techniques for aging aspen

    Science.gov (United States)

    Lance A. Asherin; Stephen A. Mata

    2001-01-01

    Aspen is notoriously difficult to age because of its light-colored wood and faint annual growth rings. Careful preparation and processing of aspen ring samples can overcome these problems, yield accurate age and growth estimates, and concisely date disturbance events present in the tree-ring record. Proper collection of aspen wood is essential in obtaining usable ring...

  13. Aspen biology, community classification, and management in the Blue Mountains

    Science.gov (United States)

    David K. Swanson; Craig L. Schmitt; Diane M. Shirley; Vicky Erickson; Kenneth J. Schuetz; Michael L. Tatum; David C. Powell

    2010-01-01

    Quaking aspen (Populus tremuloides Michx.) is a valuable species that is declining in the Blue Mountains of northeastern Oregon. This publication is a compilation of over 20 years of aspen management experience by USDA Forest Service workers in the Blue Mountains. It includes a summary of aspen biology and occurrence in the Blue Mountains, and a...

  14. Figured grain in aspen is heritable and not affected by graft-transmissible signals

    Science.gov (United States)

    Youran Fan; Kendal Rupert; Alex C. Wiedenhoeft; Keith Woeste; Christian Lexer; Richard. Meilan

    2013-01-01

    Figure can add value to wood products, but its occurrence is unpredictable. A first step in reliably producing figured wood is determining whether it is faithfully transmitted to progeny via sexual and asexual reproduction. We describe a 26-year-old male aspen genotype, designated ‘Curly Poplar’, which was shown to be a Populus × canescens hybrid using microsatellite...

  15. Aspen: A microsimulation model of the economy

    Energy Technology Data Exchange (ETDEWEB)

    Basu, N.; Pryor, R.J.; Quint, T.; Arnold, T.

    1996-10-01

    This report presents, Aspen. Sandia National Laboratories is developing this new agent-based microeconomic simulation model of the U.S. economy. The model is notable because it allows a large number of individual economic agents to be modeled at a high level of detail and with a great degree of freedom. Some features of Aspen are (a) a sophisticated message-passing system that allows individual pairs of agents to communicate, (b) the use of genetic algorithms to simulate the learning of certain agents, and (c) a detailed financial sector that includes a banking system and a bond market. Results from runs of the model are also presented.

  16. Physiological and morphological characterization of american oil palms (Elaeis oleifera HBK Cortes and their hybrids (Elaeis oleifera × Elaeis guineensis on the Indupalma plantation

    Directory of Open Access Journals (Sweden)

    Yurany Dayanna Rivera M

    2013-12-01

    Full Text Available The morphological and photosynthetic activity were characterized in six genotypes of American oil palm (E. oleifera of different origins and three of their OxG hybrids (E. oleifera × E. guineensis with a completely randomized experimental design, three replications and 16 palms per replication. Determinations were made for: photosynthesis, internal CO2 concentration, chlorophyll content, stomatal openings and density, specific leaf area, and measurements of vegetative growth. The genotypes were differentiated by growth rate, emission, area and dry weight of the leaves. The stomatal openings of all the genotypes were maximum in the morning hours, with partial closures at midday; therefore, the maximum rate of photosynthesis was between 9:00 and 12:00 hr. The "Perú" American oil palm and "hybrid 2" (Sinú-Coarí × La Mé showed higher CO2 internal concentrations, total chlorophyll contents, light saturation points and photosynthetic rates, even with low levels of photosynthetically active radiation; characteristics that indicate a high capacity for the fixation of CO2. The photosynthetic rate showed a high positive correlation with the chlorophyll content and a negative correlation with the specific leaf area. In conclusion, the "Perú" American oil palm showed relevant characteristics for use in breeding programs as female parent of OxG hybrids, while "hybrid 2", due to its outstanding morphophysiological characteristics, is considered a genotype with good agronomic performance

  17. Early Yields of Biomass Plantations in the North-Central U.S.

    Science.gov (United States)

    Edward Hansen

    1990-01-01

    A network of hybrid poplar short-rotation plantations was established across the north-central region of the U.S. during 1986-1988. This paper documents the greater than expected early yields from these plantations and dicusses potential yields and uncertainties surrounding potential yield estimates.

  18. Physiological and morphological characterization of american oil palms (Elaeis oleifera HBK Cortes) and their hybrids (Elaeis oleifera × Elaeis guineensis) on the Indupalma plantation

    OpenAIRE

    Yurany Dayanna Rivera M; Daniel Gerardo Cayón S; Jesús Edgardo López M

    2013-01-01

    The morphological and photosynthetic activity were characterized in six genotypes of American oil palm (E. oleifera) of different origins and three of their OxG hybrids (E. oleifera × E. guineensis) with a completely randomized experimental design, three replications and 16 palms per replication. Determinations were made for: photosynthesis, internal CO2 concentration, chlorophyll content, stomatal openings and density, specific leaf area, and measurements of vegetative growth. The genotypes ...

  19. Aspen Winter Conferences on High Energy

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-02-12

    The 2011 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 12 to February 18, 2011. Ninety-four participants from ten countries, and several universities and national labs attended the workshop titled, "New Data From the Energy Frontier." There were 54 formal talks, and a considerable number of informal discussions held during the week. The week's events included a public lecture ("The Hunt for the Elusive Higgs Boson" given by Ben Kilminster from Ohio State University) and attended by 119 members of the public, and a physics cafe geared for high schoolers that is a discussion with physicists. The 2011 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was "Indirect and Direct Detection of Dark Matter." It was held from February 6 to February 12, 2011. The 70 participants came from 7 countries and attended 53 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists from other institutions and countries or due to incipient collaborations. In addition, Blas Cabrera of Stanford University gave a public lecture titled "What Makes Up Dark Matter." There were 183 members of the general public in attendance. Before the lecture, 45 people attended the physics cafe to discuss dark matter. This report provides the attendee lists, programs, and announcement posters for each event.

  20. Short-rotation plantations

    Science.gov (United States)

    Philip E. Pope; Jeffery O. Dawson

    1989-01-01

    Short-rotation plantations offer several advantages over longer, more traditional rotations. They enhance the natural productivity of better sites and of tree species with rapid juvenile growth. Returns on investment are realized in a shorter period and the risk of loss is reduced compared with long term investments. Production of wood and fiber can be maximized by...

  1. The push for plantations

    DEFF Research Database (Denmark)

    Thulstrup, Andreas Waaben; Casse, Thorkil; Nielsen, Thomas Theis

    2013-01-01

    We observe signs of social differentiation, where poor households end up serving as causal labour for the richer families on their acacia plantations. In addition, the poor can be rendered more vulnerable after becoming labourers, because they may not longer have an alternative source of income, ...

  2. Spring leaf flush in aspen (Populus tremuloides) clones is altered by long-term growth at elevated carbon dioxide and elevated ozone concentration

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, Justin M., E-mail: jmcgrath@illinois.ed [Department of Plant Biology, University of Illinois, Urbana-Champaign, 190 ERML, 1201 W. Gregory Drive, Urbana, IL 61801 (United States); Karnosky, David F., E-mail: karnosky@mtu.ed [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Ainsworth, Elizabeth A., E-mail: lisa.ainsworth@ars.usda.go [Department of Plant Biology, University of Illinois, Urbana-Champaign, 190 ERML, 1201 W. Gregory Drive, Urbana, IL 61801 (United States); USDA ARS Photosynthesis Research Unit, 147 ERML, 1201 W. Gregory Drive, Urbana, IL 61801 (United States)

    2010-04-15

    Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO{sub 2}]) and elevated ozone concentration ([O{sub 3}]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work was done at the Aspen FACE experiment where aspen clones have been grown since 1997 in conditions simulating the [CO{sub 2}] and [O{sub 3}] predicted for approx2050. The responses of two clones were compared during the first month of spring leaf out when CO{sub 2} fumigation had begun, but O{sub 3} fumigation had not. Trees in elevated [CO{sub 2}] plots showed a stimulation of leaf area index (36%), while trees in elevated [O{sub 3}] plots had lower leaf area index (-20%). While individual leaf area was not significantly affected by elevated [CO{sub 2}], the photosynthetic operating efficiency of aspen leaves was significantly improved (51%). There were no significant differences in the way that the two aspen clones responded to elevated [CO{sub 2}]; however, the two clones responded differently to long-term growth at elevated [O{sub 3}]. The O{sub 3}-sensitive clone, 42E, had reduced individual leaf area when grown at elevated [O{sub 3}] (-32%), while the tolerant clone, 216, had larger mature leaf area at elevated [O{sub 3}] (46%). These results indicate a clear difference between the two clones in their long-term response to elevated [O{sub 3}], which could affect competition between the clones, and result in altered genotypic composition in future atmospheric conditions. - Spring leaf flush is stimulated by elevated [CO{sub 2}] and suppressed by elevated [O{sub 3}] in aspen (Populus tremuloides).

  3. Aspen Characteristics - Plumas National Forest, FRRD [ds375

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Plumas National Forest, Feather River Ranger...

  4. Aspen Characteristics - El Dorado National Forest [ds363

    Data.gov (United States)

    California Department of Resources — The database represents aspen stand locations and field assessments conducted in the Eldorado National Forest, Eldorado and Amador Counties, California. Data was...

  5. Automated Design Space Exploration with Aspen

    Directory of Open Access Journals (Sweden)

    Kyle L. Spafford

    2015-01-01

    Full Text Available Architects and applications scientists often use performance models to explore a multidimensional design space of architectural characteristics, algorithm designs, and application parameters. With traditional performance modeling tools, these explorations forced users to first develop a performance model and then repeatedly evaluate and analyze the model manually. These manual investigations proved laborious and error prone. More importantly, the complexity of this traditional process often forced users to simplify their investigations. To address this challenge of design space exploration, we extend our Aspen (Abstract Scalable Performance Engineering Notation language with three new language constructs: user-defined resources, parameter ranges, and a collection of costs in the abstract machine model. Then, we use these constructs to enable automated design space exploration via a nonlinear optimization solver. We show how four interesting classes of design space exploration scenarios can be derived from Aspen models and formulated as pure nonlinear programs. The analysis tools are demonstrated using examples based on Aspen models for a three-dimensional Fast Fourier Transform, the CoMD molecular dynamics proxy application, and the DARPA Streaming Sensor Challenge Problem. Our results show that this approach can compose and solve arbitrary performance modeling questions quickly and rigorously when compared to the traditional manual approach.

  6. Aspen Open Solver接口技术研究%Study on Aspen Open Solver Interfaces

    Institute of Scientific and Technical Information of China (English)

    陈智强; 陈曦; 邵之江; 张正江

    2007-01-01

    Aspen Open Solver接口集中的非线性代数方程组(NLA)部分作为研究对象,在对接口集进行系统地分析之后,利用AspenTech提供的接口代码将分别基于梯度和非基于梯度的四种求解算法嵌入生成solver组件,并实现用Aspen Plus调用该solver组件观察各种算法嵌入的结果.

  7. Methods to inventory and strip thin in dense stands of aspen root suckers

    Directory of Open Access Journals (Sweden)

    Headlee WL

    2015-10-01

    Full Text Available Aspen and their hybrids have demonstrated high biomass productivity and can produce abundant regeneration in the form of root suckers. This makes aspen particularly intriguing for bio-energy production, because replanting costs can be avoided and additional biomass can be obtained by thinning the regenerating stands. Mechanical strip thinning (removal of stems in parallel strips has been proposed as a fast and efficient method for capturing biomass that would otherwise be lost to mortality in such stands. However, determining the appropriate width for the residual rows is challenging, due to the difficulty of conducting inventories with traditional sampling tools and the variability in gap sizes between root suckers in the residual rows. In this study, we describe the development and testing of a simple inventory tool that may be used to conduct either fixed-area or variable-radius sampling in these stands. Also described is the development and testing of an equation that uses such inventory data along with Poisson distribution theory to predict the size of the largest gap between root suckers within residual rows, which in turn can be used to inform strip thinning operations. Based on the promising results of our limited tests, we encourage further evaluation of these methods with regeneration from planted and natural aspen stands, as well as other root suckering species.

  8. Shipping coal to Newcastle: are SRIC populus plantations a viable fiber production option for the central hardwoods region?

    Science.gov (United States)

    C.H. Strauss

    1991-01-01

    Production costs for short rotation, intensive culture (SRIC) Populus biomass were developed from commercial-sized plantations under investigation throughout the eastern U.S. Populus hybrid planted on good quality plantation sites at a density of 850 cuttings/acre was projected to yield an average of 7 ovendry (OD) tons/acre/year....

  9. Field performance of Populus in short-rotation intensive culture plantations in the north-central U.S.

    Science.gov (United States)

    Edward A. Hansen; Michael E. Ostry; Wendell D. Johnson; David N. Tolsted; Daniel A. Netzer; William E. Berguson; Richard B. Hall

    1994-01-01

    Describes a network of short-rotation, Populus research and demonstration plantations that has been established across a 5-state region in the north-central U.S. to identify suitable hybrid poplar clones for large-scale biomass plantations in the region. Reports 6-year results.

  10. A principal component approach for predicting the stem volume in Eucalyptus plantations in Brazil using airborne LiDAR data

    Science.gov (United States)

    Carlos Alberto Silva; Carine Klauberg; Andrew T. Hudak; Lee A. Vierling; Veraldo Liesenberg; Samuel P. C. e Carvalho; Luiz C. E. Rodriguez

    2016-01-01

    Improving management practices in industrial forest plantations may increase production efficiencies, thereby reducing pressures on native tropical forests for meeting global pulp needs. This study aims to predict stem volume (V) in plantations of fast-growing Eucalyptus hybrid clones located in southeast Brazil using field plot and airborne Light Detection...

  11. Drought causes reduced growth of trembling aspen in western Canada.

    Science.gov (United States)

    Chen, Lei; Huang, Jian-Guo; Alam, Syed Ashraful; Zhai, Lihong; Dawson, Andria; Stadt, Kenneth J; Comeau, Philip G

    2017-07-01

    Adequate and advance knowledge of the response of forest ecosystems to temperature-induced drought is critical for a comprehensive understanding of the impacts of global climate change on forest ecosystem structure and function. Recent massive decline in aspen-dominated forests and an increased aspen mortality in boreal forests have been associated with global warming, but it is still uncertain whether the decline and mortality are driven by drought. We used a series of ring-width chronologies from 40 trembling aspen (Populus tremuloides Michx.) sites along a latitudinal gradient (from 52° to 58°N) in western Canada, in an attempt to clarify the impacts of drought on aspen growth by using Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). Results indicated that prolonged and large-scale droughts had a strong negative impact on trembling aspen growth. Furthermore, the spatiotemporal variability of drought indices is useful for explaining the spatial heterogeneity in the radial growth of trembling aspen. Due to ongoing global warming and rising temperatures, it is likely that severer droughts with a higher frequency will occur in western Canada. As trembling aspen is sensitive to drought, we suggest that drought indices could be applied to monitor the potential effects of increased drought stress on aspen trees growth, achieve classification of eco-regions and develop effective mitigation strategies to maintain western Canadian boreal forests. © 2017 John Wiley & Sons Ltd.

  12. Predation risk and elk-aspen foraging patterns

    Science.gov (United States)

    Clifford A. White; Michael C. Feller

    2001-01-01

    Elk-aspen foraging patterns may be influenced by cover type, distance from roads or trails, the type of user on road or trail (park visitor, human hunter, or predator), and two general states of aspen condition (open-grown or thicket). Pellet group and browse utilization transects in the Canadian Rockies showed that elk were attracted to roads used by park visitors and...

  13. Aspen Competition Drives Innovative Ideas for Community Colleges

    Science.gov (United States)

    Gonzalez, Jennifer

    2012-01-01

    When Valencia College became the first recipient of the Aspen Prize for Community College Excellence last month, an unsung sector earned uncommon recognition. Now that the speeches are over and the prize money has been awarded, the Aspen Institute is sharing early lessons from its yearlong effort to determine the top community college in the…

  14. What Is Community College Excellence? Lessons from the Aspen Prize

    Science.gov (United States)

    Wyner, Joshua

    2012-01-01

    Over the past year, in a process to select the winner of the Aspen Prize for Community College Excellence, the Aspen Institute has convened national experts to define and determine how to measure "excellence," to identify community colleges with high levels of student success, and to help more community colleges understand what can be done to…

  15. Aspen Handbook on the Media: Research, Publications, Organizations.

    Science.gov (United States)

    Rivers, William L., Ed.; Slater, William T., Ed.

    The Aspen Program on Communications and Society represents a major attempt to bring together men, ideas, and institutions to pioneer in the communications field, to identify the main communications issues confronting society, and to develop effective programs to implement these policies. This handbook was compiled as a result of an Aspen program…

  16. Do pine trees in aspen stands increase bird diversity?

    Science.gov (United States)

    Mark A. Rumble; Lester D. Flake; Todd R. Mills; Brian L. Dykstra

    2001-01-01

    In the Black Hills of South Dakota, quaking aspen (Populus tremuloides) is being replaced by conifers through fire suppression and successional processes. Although the Black Hills National forest is removing conifers (primarily ponderosa pine [Pinus ponderosa]) to increase the aspen communities in some mixed stands, Forest Plan guidelines allow four conifers per...

  17. Soil erosion: perennial crop plantations

    NARCIS (Netherlands)

    Hartemink, A.E.

    2006-01-01

    Plantation agriculture is an important form of land-use in the tropics. Large areas of natural and regenerated forest have been cleared for growing oil palm, rubber, cocoa, coffee, and other perennial tree crops. These crops grown both on large scale plantations and by smallholders are important sou

  18. Polyploidy in aspen alters plant physiology and drought sensitivity

    Science.gov (United States)

    Greer, B.; Still, C. J.; Brooks, J. R.; Meinzer, F. C.

    2015-12-01

    Polyploids of quaking aspen (Populus tremuloides) may be better suited to dry climatic conditions than diploids. However, the expression of diploid and polyploid functional traits, including water use efficiency, an important component of drought avoidance and tolerance, are not well understood in quaking aspen. In this study diploid and triploid aspen clones' leaf, ramet, and stand functional traits were measured near the Rocky Mountain Biological Laboratory in Gothic, Colorado. The physiology of diploid and triploid aspen, including leaf size, chlorophyll content, stomatal size and density and stomatal conductance, as well as growth rates and carbon isotope discrimination in response to climate (measured in tree rings), were found to be significantly different between ploidy levels. These findings demonstrate different sensitivities of diploid and triploid clones to drought related climate stressors which may impact strategies for aspen forest management and conservation.

  19. ASPEN PLUS在化工设计中的应用%ASPEN PLUS Applications in Chemical Design

    Institute of Scientific and Technical Information of China (English)

    陈坚

    2011-01-01

    Using the ASPEN PLUS simulation methanol-water distillation separation,through sensitivity analysis and mapping tools to optimize the design.%使用ASPEN PLUS模拟甲醇一水精馏分离,通过灵敏度分析和绘图工具优化设计。

  20. Spring leaf flush in aspen (Populus tremuloides) clones is altered by long-term growth at elevated carbon dioxide and elevated ozone concentration.

    Science.gov (United States)

    McGrath, Justin M; Karnosky, David F; Ainsworth, Elizabeth A

    2010-04-01

    Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO(2)]) and elevated ozone concentration ([O(3)]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work was done at the Aspen FACE experiment where aspen clones have been grown since 1997 in conditions simulating the [CO(2)] and [O(3)] predicted for approximately 2050. The responses of two clones were compared during the first month of spring leaf out when CO(2) fumigation had begun, but O(3) fumigation had not. Trees in elevated [CO(2)] plots showed a stimulation of leaf area index (36%), while trees in elevated [O(3)] plots had lower leaf area index (-20%). While individual leaf area was not significantly affected by elevated [CO(2)], the photosynthetic operating efficiency of aspen leaves was significantly improved (51%). There were no significant differences in the way that the two aspen clones responded to elevated [CO(2)]; however, the two clones responded differently to long-term growth at elevated [O(3)]. The O(3)-sensitive clone, 42E, had reduced individual leaf area when grown at elevated [O(3)] (-32%), while the tolerant clone, 216, had larger mature leaf area at elevated [O(3)] (46%). These results indicate a clear difference between the two clones in their long-term response to elevated [O(3)], which could affect competition between the clones, and result in altered genotypic composition in future atmospheric conditions.

  1. Changes to Extractable Soil Amino Compounds Under Elevated CO2 and Ozone in an Aspen Plantation

    Science.gov (United States)

    Top, S. M.; Filley, T. R.; Zhang, X.

    2011-12-01

    Forests growing under elevated concentrations of atmospheric CO2 and ozone exhibit changes to root and foliar chemistry and quality that are related to changes in physiology, N limitation, and leaf damage. Additionally, there are documented changes to the activity of some understory invertebrate populations, and a variety of responses to soil organic matter ranging from accrual in the upper few centimeters to loss of soil C and N over the upper 20 cm. Under such conditions, however, the cycling of specific amino compounds is poorly understood. Knowledge of the role that new plant N plays in supporting soil microbial populations and soil C and N dynamics is important to fully understand relationships between N limitation under elevated CO2-induced productivity increases and available organic N pools in soil. We investigated the composition and concentration of hydrolysable amino compounds (amino acids and amino sugars) in litter, roots, soil, and earthworm fecal matter from the free-air CO2 enrichment (FACE) sites at Rhinelander, WI. Under elevated CO2 amino acids, when normalized to total N, exhibited change in both amount (decrease) and composition among roots (amino acids showed only minor changes with depth in the ambient and ozone treatments. Ozonated rings exhibited a lower release of amino compounds (with respect to total N) compared to ambient and elevated CO2, which may suggest poorer quality input. For soil organic matter extractable amino acids (normalized to total soil N) exhibited changes similar to roots among the treatment. These results indicate that CO2 and ozone significantly influence amino compound dynamics in both soil and input which should impact the overall ability to decompose and preserve soils in such environments.

  2. Somatic Embryogenesis from Cell Suspension Cultures of Aspen Clone

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Suspension cultures initiated from callus derived from petiole explants of aspen hybrid (Populus tremuloides × P.tremula) produced somatic embryos. Callus was induced on a MS medium supplemented with 5 mg·L-1 2,4-D and 0.05 mg·L-1 zeatin under light conditions. Embryogenic calli were obtained when a subsequent subculture of calli was suspended in the same basal medium with 10 mg·L-1 2,4-D. The highest number of globular embryos were induced from embryogenic calli by cell suspension culture in a MS liquid medium supplemented with 10 mg·L-1 2,4-D. Genotype and 2,4-D concentration were vital to the induction of embryogenic calli producing competent cells. Embryogenic calli for each genotype were heterogeneous. Green calli with gel-like consistency could yield more competent cells than light yellow embryogenic calli. However, some globular embryos broke into slices and some developed abnormally after one month of culture under the same or other hormonal conditions.

  3. Aspen SUCROSE TRANSPORTER3 allocates carbon into wood fibers.

    Science.gov (United States)

    Mahboubi, Amir; Ratke, Christine; Gorzsás, András; Kumar, Manoj; Mellerowicz, Ewa J; Niittylä, Totte

    2013-12-01

    Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species, including Populus species, the majority of this carbon is derived from sucrose (Suc) transported in the phloem. The mechanism of radial Suc transport from phloem to developing wood is not well understood. We investigated the role of active Suc transport during secondary cell wall formation in hybrid aspen (Populus tremula × Populus tremuloides). We show that RNA interference-mediated reduction of PttSUT3 (for Suc/H(+) symporter) during secondary cell wall formation in developing wood caused thinner wood fiber walls accompanied by a reduction in cellulose and an increase in lignin. Suc content in the phloem and developing wood was not significantly changed. However, after (13)CO2 assimilation, the SUT3RNAi lines contained more (13)C than the wild type in the Suc-containing extract of developing wood. Hence, Suc was transported into developing wood, but the Suc-derived carbon was not efficiently incorporated to wood fiber walls. A yellow fluorescent protein:PttSUT3 fusion localized to plasma membrane, suggesting that reduced Suc import into developing wood fibers was the cause of the observed cell wall phenotype. The results show the importance of active Suc transport for wood formation in a symplasmically phloem-loading tree species and identify PttSUT3 as a principal transporter for carbon delivery into secondary cell wall-forming wood fibers.

  4. Dynamics of soil nutrients in larch plantations

    Institute of Scientific and Technical Information of China (English)

    Yan Deren; Chen Jinglian

    1999-01-01

    The annual dynamic changes of soil nutrients were measured in pure larch plantation and in mixed larch plantation in the arboretum of Inner Mongolia Academy of Forestry Science, Huhehaote. The results showed that soil nutrients in pure larch plantations changed rapidly in July and August. The variation of soil nutrients is more stable in mixed larch plantation. Compared with the pure larch plantation, the content of soil nutrients in mixed larch plantation obviously increased. The soil degradation occurred in the pure larch plantation, and related to the forest age.

  5. Genetic diversity in aspen and its relation to arthropod abundance.

    Science.gov (United States)

    Zhang, Chunxia; Vornam, Barbara; Volmer, Katharina; Prinz, Kathleen; Kleemann, Frauke; Köhler, Lars; Polle, Andrea; Finkeldey, Reiner

    2014-01-01

    The ecological consequences of biodiversity have become a prominent public issue. Little is known on the effect of genetic diversity on ecosystem services. Here, a diversity experiment was established with European and North American aspen (Populus tremula, P. tremuloides) planted in plots representing either a single deme only or combinations of two, four and eight demes. The goals of this study were to explore the complex inter- and intraspecific genetic diversity of aspen and to then relate three measures for diversity (deme diversity, genetic diversity determined as Shannon index or as expected heterozygosity) to arthropod abundance. Microsatellite and AFLP markers were used to analyze the genetic variation patterns within and between the aspen demes and deme mixtures. Large differences were observed regarding the genetic diversity within demes. An analysis of molecular variance revealed that most of the total genetic diversity was found within demes, but the genetic differentiation among demes was also high. The complex patterns of genetic diversity and differentiation resulted in large differences of the genetic variation within plots. The average diversity increased from plots with only one deme to plots with two, four, and eight demes, respectively and separated plots with and without American aspen. To test whether intra- and interspecific diversity impacts on ecosystem services, arthropod abundance was determined. Increasing genetic diversity of aspen was related to increasing abundance of arthropods. However, the relationship was mainly driven by the presence of American aspen suggesting that species identity overrode the effect of intraspecific variation of European aspen.

  6. Biomass plantations - energy farming

    Energy Technology Data Exchange (ETDEWEB)

    Paul, S.

    1981-02-01

    Mounting oil import bills in India are restricting her development programmes by forcing the cutting down of the import of other essential items. But the countries of the tropics have abundant sunlight and vast tracts of arable wastelands. Energy farming is proposed in the shape of energy plantations through forestry or energy cropping through agricultural media, to provide power fuels for transport and the industries and also to provide fuelwoods for the domestic sector. Short rotation cultivation is discussed and results are given of two main species that are being tried, ipil-ipil and Casuarina. Evaluations are made on the use of various crops such as sugar cane, cassava and kenaf as fuel crops together with hydrocarbon plants and aquatic biomass. (Refs. 20)

  7. The Application of Aspen Plus Simulation in Coal Gasification%Aspen Plus在煤气化中的应用

    Institute of Scientific and Technical Information of China (English)

    刘晓花; 刘丹; 郝婷; 靳皎; 杨会民; 刘巧霞

    2016-01-01

    Aspen Plus是一种基于稳态化工模拟、优化、灵敏度分析和经济评价的大型化工流程模拟软件,由于其优良的性能而被广泛应用于化工领域.文章主要介绍了Aspen Plus软件的特点,并且综述了近几年来Aspen Plus在煤气化领域中的研究成果和发展概况.

  8. Overview of Rattan Plantation Management

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Rattans are climbing spiny plants that are regarded as an important kind of commercial non-timber forest products. Rattan resources are dwindling rapidly due to over-exploitation in the wild and the loss of tropical forest cover. These threaten the sustainable utilization of rattan resources and long-term survival of the rattan industry. The development of rattan plantation and the improvement of management technique are hence important. The major issues on plantation management are reviewed in this pap...

  9. A review of the potential effects of climate change on quaking aspen (Populus tremuloides) in the Western United States and a new tool for surveying sudden aspen decline

    Science.gov (United States)

    Toni Lyn Morelli; Susan C. Carr

    2011-01-01

    We conducted a literature review of the effects of climate on the distribution and growth of quaking aspen (Populus tremuloides Michx.) in the Western United States. Based on our review, we summarize models of historical climate determinants of contemporary aspen distribution. Most quantitative climate-based models linked aspen presence and growth...

  10. Aspen Grupp võitis RKASi / Lemmi Kann

    Index Scriptorium Estoniae

    Kann, Lemmi

    2008-01-01

    Ehitusfirma Aspen Grupp OÜ võitis Tallinna ringkonnakohtus Riigi Kinnisvara AS-i, kes diskvalifitseeris ehitusfirma riigihankelt seaduses olnud maksevõlgnevuse keelu tõttu. Vt. samas: Lahendust ootavad veel kaks kohtuasja

  11. Long-term monitoring of western aspen--lessons learned.

    Science.gov (United States)

    Strand, E K; Bunting, S C; Starcevich, L A; Nahorniak, M T; Dicus, G; Garrett, L K

    2015-08-01

    Aspen woodland is an important ecosystem in the western United States. Aspen is currently declining in western mountains; stressors include conifer expansion due to fire suppression, drought, disease, heavy wildlife and livestock use, and human development. Forecasting of tree species distributions under future climate scenarios predicts severe losses of western aspen within the next 50 years. As a result, aspen has been selected as one of 14 vital signs for long-term monitoring by the National Park Service Upper Columbia Basin Network. This article describes the development of a monitoring protocol for aspen including inventory mapping, selection of sampling locations, statistical considerations, a method for accounting for spatial dependence, field sampling strategies, and data management. We emphasize the importance of collecting pilot data for use in statistical power analysis and semi-variogram analysis prior to protocol implementation. Given the spatial and temporal variability within aspen stem size classes, we recommend implementing permanent plots that are distributed spatially within and among stands. Because of our careful statistical design, we were able to detect change between sampling periods with desired confidence and power. Engaging a protocol development and implementation team with necessary and complementary knowledge and skills is critical for success. Besides the project leader, we engaged field sampling personnel, GIS specialists, statisticians, and a data management specialist. We underline the importance of frequent communication with park personnel and network coordinators.

  12. Management of aspen plant communities on the National Elk Refuge, Wyoming

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — There are 1,860 acres (753 ha) of aspen (Populus tremuloides) plant communities on the National Elk Refuge (NER). Aspen is an important tree species on the Refuge,...

  13. Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood.

    Science.gov (United States)

    Derba-Maceluch, Marta; Awano, Tatsuya; Takahashi, Junko; Lucenius, Jessica; Ratke, Christine; Kontro, Inkeri; Busse-Wicher, Marta; Kosik, Ondrej; Tanaka, Ryo; Winzéll, Anders; Kallas, Åsa; Leśniewska, Joanna; Berthold, Fredrik; Immerzeel, Peter; Teeri, Tuula T; Ezcurra, Ines; Dupree, Paul; Serimaa, Ritva; Mellerowicz, Ewa J

    2015-01-01

    Certain xylanases from family GH10 are highly expressed during secondary wall deposition, but their function is unknown. We carried out functional analyses of the secondary-wall specific PtxtXyn10A in hybrid aspen (Populus tremula × tremuloides). PtxtXyn10A function was analysed by expression studies, overexpression in Arabidopsis protoplasts and by downregulation in aspen. PtxtXyn10A overexpression in Arabidopsis protoplasts resulted in increased xylan endotransglycosylation rather than hydrolysis. In aspen, the enzyme was found to be proteolytically processed to a 68 kDa peptide and residing in cell walls. Its downregulation resulted in a corresponding decrease in xylan endotransglycosylase activity and no change in xylanase activity. This did not alter xylan molecular weight or its branching pattern but affected the cellulose-microfibril angle in wood fibres, increased primary growth (stem elongation, leaf formation and enlargement) and reduced the tendency to form tension wood. Transcriptomes of transgenic plants showed downregulation of tension wood related genes and changes in stress-responsive genes. The data indicate that PtxtXyn10A acts as a xylan endotransglycosylase and its main function is to release tensional stresses arising during secondary wall deposition. Furthermore, they suggest that regulation of stresses in secondary walls plays a vital role in plant development.

  14. Artificially decreased vapour pressure deficit in field conditions modifies foliar metabolite profiles in birch and aspen.

    Science.gov (United States)

    Lihavainen, Jenna; Keinänen, Markku; Keski-Saari, Sarita; Kontunen-Soppela, Sari; Sõber, Anu; Oksanen, Elina

    2016-07-01

    Relative air humidity (RH) is expected to increase in northern Europe due to climate change. Increasing RH reduces the difference of water vapour pressure deficit (VPD) between the leaf and the atmosphere, and affects the gas exchange of plants. Little is known about the effects of decreased VPD on plant metabolism, especially under field conditions. This study was conducted to determine the effects of artificially decreased VPD on silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L.×P. tremuloides Michx.) foliar metabolite and nutrient profiles in a unique free air humidity manipulation (FAHM) field experiment during the fourth season of humidity manipulation, in 2011. Long-term exposure to decreased VPD modified nutrient homeostasis in tree leaves, as demonstrated by a lower N concentration and N:P ratio in aspen leaves, and higher Na concentration and lower K:Na ratio in the leaves of both species in decreased VPD than in ambient VPD. Decreased VPD caused a shift in foliar metabolite profiles of both species, affecting primary and secondary metabolites. Metabolic adjustment to decreased VPD included elevated levels of starch and heptulose sugars, sorbitol, hemiterpenoid and phenolic glycosides, and α-tocopherol. High levels of carbon reserves, phenolic compounds, and antioxidants under decreased VPD may modify plant resistance to environmental stresses emerging under changing climate.

  15. Aspen Global Change Institute Summer Science Sessions

    Energy Technology Data Exchange (ETDEWEB)

    Katzenberger, John; Kaye, Jack A

    2006-10-01

    The Aspen Global Change Institute (AGCI) successfully organized and convened six interdisciplinary meetings over the course of award NNG04GA21G. The topics of the meetings were consistent with a range of issues, goals and objectives as described within the NASA Earth Science Enterprise Strategic Plan and more broadly by the US Global Change Research Program/Our Changing Planet, the more recent Climate Change Program Strategic Plan and the NSF Pathways report. The meetings were chaired by two or more leaders from within the disciplinary focus of each session. 222 scholars for a total of 1097 participants-days were convened under the auspices of this award. The overall goal of each AGCI session is to further the understanding of Earth system science and global environmental change through interdisciplinary dialog. The format and structure of the meetings allows for presentation by each participant, in-depth discussion by the whole group, and smaller working group and synthesis activities. The size of the group is important in terms of the group dynamics and interaction, and the ability for each participant's work to be adequately presented and discussed within the duration of the meeting, while still allowing time for synthesis

  16. Lichen community change in response to succession in aspen forests of the southern Rocky Mountains

    Science.gov (United States)

    Paul C. Rogers; Ronald J. Ryel

    2008-01-01

    In western North America, quaking aspen (Populus tremuloides) is the most common hardwood in montane landscapes. Fire suppression, grazing and wildlife management practices, and climate patterns of the past century are all potential threats to aspen coverage in this region. If aspen-dependent species are losing habitat, this raises concerns about...

  17. 77 FR 60373 - Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and Piute...

    Science.gov (United States)

    2012-10-03

    ... Forest Service Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and... alternatives, within the Monroe Mountain Aspen Ecosystems Restoration Project area. The purpose of the Monroe Mountain Aspen Ecosystems Restoration Project is to implement land management activities that are...

  18. Aspen Plus功能扩展方法探讨%Discussions on Method of Function Development for Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    原璐; 吕海霞; 项曙光

    2005-01-01

    对化工过程模拟软件Aspen Plus的用户模型的开发进行了分析,探讨了Aspen Plus用户模型开发步骤和编写方法.Aspen Plus支持6种用户模型,其编写除了要遵循一个通用的规则外,针对每一种用户模型又有不同的定义方式.用户模型的编译和连接通过Aspen Plus提供的编译程序aspcomp和asplink来完成,最终生成一个目标模块文件或动态连接库.将该目标模块文件或动态连接库复制到Aspen Plus的执行目录下,即完成一个用户模型的开发全过程.最后给出一个具体用户模型的例子,以帮助用户熟悉该方法.

  19. Wood Pyrolysis Using Aspen Plus Simulation and Industrially Applicable Model

    Directory of Open Access Journals (Sweden)

    Lestinsky Pavel

    2016-03-01

    Full Text Available Over the past decades, a great deal of experimental work has been carried out on the development of pyrolysis processes for wood and waste materials. Pyrolysis is an important phenomenon in thermal treatment of wood, therefore, the successful modelling of pyrolysis to predict the rate of volatile evolution is also of great importance. Pyrolysis experiments of waste spruce sawdust were carried out. During the experiment, gaseous products were analysed to determine a change in the gas composition with increasing temperature. Furthermore, the model of pyrolysis was created using Aspen Plus software. Aspects of pyrolysis are discussed with a description of how various temperatures affect the overall reaction rate and the yield of volatile components. The pyrolysis Aspen plus model was compared with the experimental data. It was discovered that the Aspen Plus model, being used by several authors, is not good enough for pyrolysis process description, but it can be used for gasification modelling.

  20. PERACETIC ACID PRETREATMENT OF ALFALFA STEM AND ASPEN BIOMASS

    OpenAIRE

    Lei Xu; Ulrike W. Tschirner

    2011-01-01

    Alfalfa stems and ground aspen were exposed to peracetic acid (0.5 to 9% on biomass) at temperatures ranging from 40 to 100° C and reaction times from 1 to 5 hours. Glucose release as a percentage of total cellulose content was determined using subsequent standard enzymatic hydrolysis. Statistical analysis confirmed that aspen showed a strong response to peracetic acid addition rate. 9% peracetic acid removed 14% of the original lignin and increased the rate of glucose release from 23% to 44%...

  1. Aspen Plus 7.3在精馏设计中的应用%The Application of Aspen Plus 7.3 in Distillation Design

    Institute of Scientific and Technical Information of China (English)

    薛科创; 许航线

    2014-01-01

    Aspen Plus 7.3作为化工设计的首选软件,得到了众多化工爱好者的青睐。以Aspen Plus 7.3在精馏设计中的应用为例,介绍了Aspen Plus 7.3在化工设计中的步骤和方法,为我们进行化工设计和原有工艺改进提供了方法。%Aspen Plus 7.3 as the chemical engineering design software of the first choice have liked by many chemical enthusiasts. This paper shows that Aspen Plus 7.3 in the chemical design steps and methods for us to carry out chemical process design and improvement of existing methods by Aspen Plus 8.0 in distillation design application as an example.

  2. Populations of aspen (Populus tremuloides Michx.) with different evolutionary histories differ in their climate occupancy.

    Science.gov (United States)

    Greer, Burke T; Still, Christopher; Howe, Glenn T; Tague, Christina; Roberts, Dar A

    2016-05-01

    Quaking aspens (Populus tremuloides Michx.) are found in diverse habitats throughout North America. While the biogeography of aspens' distribution has been documented, the drivers of the phenotypic diversity of aspen are still being explored. In our study, we examined differences in climate between northern and southwestern populations of aspen, finding large-scale differences between the populations. Our results suggest that northern and southwestern populations live in distinct climates and support the inclusion of genetic and phenotypic data with species distribution modeling for predicting aspens' distribution.

  3. Application of Model Analysis Tools in ASPEN PLUS%ASPEN PLUS模型分析工具的应用

    Institute of Scientific and Technical Information of China (English)

    吴建方

    2011-01-01

    随着计算机技术的发展,ASPENPLUS在化工中的应用越来越广泛,文章对ASPENPLUS模拟软件进行概括,重点论述模型分析工具在化工中的应用。%With the development computer technique,ASPEN PLUS is used more and more widely in the chemical engineering,model analysis tools is mainly discussed in the chemical engineering according to summarizing ASPEN PLUS.

  4. Analyses of GA20ox- and GID1-over-expressing aspen suggest that gibberellins play two distinct roles in wood formation.

    Science.gov (United States)

    Mauriat, Mélanie; Moritz, Thomas

    2009-06-01

    Gibberellins (GAs) are involved in many aspects of plant development, including shoot growth, flowering and wood formation. Increased levels of bioactive GAs are known to induce xylogenesis and xylem fiber elongation in aspen. However, there is currently little information on the response pathway(s) that mediate GA effects on wood formation. Here we characterize an important element of the GA pathway in hybrid aspen: the GA receptor, GID1. Four orthologs of GID1 were identified in Populus tremula x P. tremuloides (PttGID1.1-1.4). These were functional when expressed in Arabidopsis thaliana, and appear to present a degree of sub-functionalization in hybrid aspen. PttGID1.1 and PttGID1.3 were over-expressed in independent lines of hybrid aspen using either the 35S promoter or a xylem-specific promoter (LMX5). The 35S:PttGID1 over-expressors shared several phenotypic traits previously described in 35S:AtGA20ox1 over-expressors, including rapid growth, increased elongation, and increased xylogenesis. However, their xylem fibers were not elongated, unlike those of 35S:AtGA20ox1 plants. Similar differences in the xylem fiber phenotype were observed when PttGID1.1, PttGID1.3 or AtGA20ox1 were expressed under the control of the LMX5 promoter, suggesting either that PttGID1.1 and PttGID1.3 play no role in fiber elongation or that GA homeostasis is strongly controlled when GA signaling is altered. Our data suggest that GAs are required in two distinct wood-formation processes that have tissue-specific signaling pathways: xylogenesis, as mediated by GA signaling in the cambium, and fiber elongation in the developing xylem.

  5. RESTORATION OF QUAKING ASPEN WOODLANDS INVADED BY WESTERN JUNIPER

    Science.gov (United States)

    Quaking aspen woodlands are important plant communities in the interior mountains of the western United States, providing essential habitat for many wildlife species and contain a high diversity of understory plants. Western juniper woodlands are rapidly replacing lower elevation (<6800 ft) quaking...

  6. The 2013 Aspen Prize for Community College Excellence

    Science.gov (United States)

    Perlstein, Linda

    2013-01-01

    For millions of Americans, community colleges provide an essential pathway to well-paying jobs and continuing higher education. The Aspen Prize for Community College Excellence honors those institutions that strive for and achieve exceptional levels of success for all students, while they are in college and after they graduate. Community colleges…

  7. Defining Excellence: Lessons from the 2013 Aspen Prize Finalists

    Science.gov (United States)

    Aspen Institute, 2013

    2013-01-01

    In many respects, one couldn't find a group of 10 schools more diverse than the finalists for the 2013 Aspen Prize for Community College Excellence. One community college serves 1,500 students, another 56,000. There are institutions devoted primarily--even solely--to technical degrees, and ones devoted mainly to preparing students for further…

  8. Widespread triploidy in Western North American aspen (Populus tremuloides).

    Science.gov (United States)

    Mock, Karen E; Callahan, Colin M; Islam-Faridi, M Nurul; Shaw, John D; Rai, Hardeep S; Sanderson, Stewart C; Rowe, Carol A; Ryel, Ronald J; Madritch, Michael D; Gardner, Richard S; Wolf, Paul G

    2012-01-01

    We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  9. Quaking aspen and the human experience: Dimensions, issues, and challenges

    Science.gov (United States)

    Stephen F. McCool

    2001-01-01

    Humans assign four types of meanings to aspen landscapes: (1) instrumental meanings dealing with the attainment of a goal - such as production of pulp or provision of recreation opportunities; (2) aesthetic meanings; (3) cultural/symbolic meanings dealing with spiritual and social attachments to landscapes; and (4) individual/expressive meanings derived out of...

  10. Widespread triploidy in Western North American aspen (Populus tremuloides.

    Directory of Open Access Journals (Sweden)

    Karen E Mock

    Full Text Available We document high rates of triploidy in aspen (Populus tremuloides across the western USA (up to 69% of genets, and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species, climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  11. Orbital Express mission operations planning and resource management using ASPEN

    Science.gov (United States)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel

    2008-04-01

    As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less labor-power rises. Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Like a tow-truck delivering gas to a car on the road, the "servicing" satellite of OE had to find the "client" from several kilometers away, connect directly to the client, and transfer fluid (or a battery) autonomously, while on earth-orbit. The mission met 100% of its success criteria, and proved that autonomous satellite servicing is now a reality for space operations. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. As the constraints for execution could change weekly, daily, and even hourly, the tools used create the mission execution plans needed to be flexible and adaptable to many different kinds of changes. At the same time, the hard constraints of the plans needed to be maintained and satisfied. The Automated Scheduling and Planning Environment (ASPEN) tool, developed at the Jet Propulsion Laboratory, was used to create the schedule of events in each daily plan for the two satellites of the OE mission. This paper presents an introduction to the ASPEN tool, an overview of the constraints of the OE domain, the variable conditions that were presented within the mission, and the solution to operations that ASPEN provided. ASPEN has been used in several other domains, including research rovers, Deep Space Network scheduling research, and in flight operations for the NASA's Earth Observing One mission's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

  12. Tall shrub layer biomass in conifer plantations in northeastern Minnesota.

    Science.gov (United States)

    Lewis F. Ohmann

    1982-01-01

    Provides estimates of biomass (pounds/acre) for tall shrub species in 53 conifer plantations in northeastern Minnesota. The estimates are analyzed by plantation age and silvicultural practices used to establish and release the plantations.

  13. Assessing Site Availability of Aspen and Northern Hardwoods for Potential Feedstock Development in Michigan: A Case Study

    Directory of Open Access Journals (Sweden)

    Sara Alian

    2015-05-01

    Full Text Available The importance of wood and wood byproducts as biomass feedstocks is of increasing interest as a source of ethanol and electricity. Second generation woody feedstock sources in Michigan, e.g., hybrid poplar and hybrid willow (Populus spp., and native forests, particularly aspen and northern hardwoods, are a potential source of woody biomass for these uses. This study provides a geographic information system (GIS framework for assessing the current spatial extent of aspen and northern hardwoods and their proximity to roads. Additionally, the potential for expanding the area of these feedstock sources based on pre-European settlement vegetation cover is assessed. Utilizing GIS technology to compile, edit and analyze available geospatial data (e.g., present day and pre-European settlement land use/cover, soils, road infrastructure, and land ownership for counties located in the eastern half of the Upper Peninsula and northern half of the Lower Peninsula of Michigan provides a robust framework for various management scenarios to be evaluated in a cost effective manner and foster better decision making.

  14. aspenONE先进控制和优化集成解决方案

    Institute of Scientific and Technical Information of China (English)

    竺建敏

    2006-01-01

    Aspen DMCplus多变量模型预估先进过程控制系统、Aspen Apollo非线性多变量模型预估先进过程控制系统、Aspen Plus Optimizer闭环实时优化系统、Aspen Blend油品调合多变量先进过程控制与优化系统、Aspen Watch在线监控系统、Aspen IQmodel Powertools软仪表系统,以及Aspen SmartStep智能化的控制器维护系统等构成了AspenTech的aspenONE先进过程控制和优化集成解决方案(见图1)。AspenTech的多变量模型预估控制技术与智能化的控制器维护系统和在线监控系统相结合,

  15. Quantifying the consequences of conifer succession in aspen stands: decline in a biodiversity-supporting community.

    Science.gov (United States)

    McCullough, S A; O'Geen, A T; Whiting, M L; Sarr, D A; Tate, K W

    2013-07-01

    Quaking aspen (Populus tremuloides Michaux) stands are important for biodiversity in conifer-dominated forest landscapes. Our goal was to quantify the consequences of conifer succession on understory diversity and litter quality, as well as associated changes in aspen stand condition. We studied aspen stands on national park land in the transition zone between the northern Sierra Nevada and southern Cascade mountain ranges. We field-measured ten metrics of aspen stand condition in 29 aspen stands. Along a gradient of increasing current conifer cover, we observed decreases in herbaceous species diversity and richness and an increase in forest floor O horizon depth. We interpreted aerial photos from 1952 and 1998 to determine whether directional changes in conifer cover had occurred in the stands over the past half century, and used regression modeling to associate succession with the observed range of aspen stand condition. From the period 1952 to 1998, we found that conifer encroachment occurred in half the sampled stands, with an average increase in conifer cover of 1% a year. Aspen were persistent in the remaining stands. Stand cover dynamics and percent total canopy cover interacted to influence species richness, diversity, aspen sprouting, and litter quality. In stands with conifer encroachment, both understory species richness and diversity declined. Although aspen sprouting increased, aspen establishment declined and the relative mass of woody to fine soil litter increased.

  16. Mission-Driven Media: Not Just Survival, but Success. A Report of the Aspen Institute Forum on Diversity and the Media (Aspen, Colorado, July 11-14, 2001).

    Science.gov (United States)

    Levi, Titus

    This report of the Aspen Institute Forum on Diversity and the Media, supported and funded by the Ford Foundation, is not a typical Aspen Institute forum report. It explores an issue--the sustainability of mission-driven media--and through this discussion becomes a kind of resource guide for managers and others who desire to preserve and promote…

  17. Stand Composition, Tree Proximity and Size Have Minimal Effects on Leaf Function of Coexisting Aspen and Subalpine Fir.

    Science.gov (United States)

    Rhodes, Aaron C; Barney, Trevor; St Clair, Samuel B

    2016-01-01

    Forest structural heterogeneity due to species composition, spatial relationships and tree size are widely studied patterns in forest systems, but their impacts on tree function are not as well documented. The objective of this study was to examine how stand composition, tree proximity relationships and tree size influence the leaf functional traits of aspen, an early successional species, and subalpine fir, a climax species. We measured foliar nutrients, nonstructural carbohydrates (aspen only), defense chemistry and xylem water potential of aspen and subalpine fir trees in three size classes growing in close proximity or independently from other trees under three stand conditions: aspen dominant, aspen-conifer mixed, and conifer dominant stands. Close proximity of subalpine fir to aspen reduced aspen's storage of starch in foliar tissue by 17% suggesting that competition between these species may have small effects on carbon metabolism in aspen leaves. Simple sugar (glucose + sucrose) concentrations in aspen leaves were slightly higher in larger aspen trees than smaller trees. However, no differences were found in stem water potential, foliar concentrations of nitrogen, phosphorus, or secondary defense chemicals of aspen or subalpine fir across the gradients of stand composition, tree proximity or tree size. These results suggest that mechanisms of coexistence allow both aspen and subalpine fir to maintain leaf function across a wide range of stand structural characteristics. For aspen, resource sharing through its clonal root system and high resource storage capacity may partially contribute to its functional stability in mixed aspen-conifer stands.

  18. The Application of Aspen Plus Simulation in Fluorine Chemistry%Aspen Plus模拟在氟化工中的应用研究

    Institute of Scientific and Technical Information of China (English)

    李盛姬; 田端正; 吴江平; 张建君

    2011-01-01

    Aspen Plus is a large-scale process simulation system which is used universally in producing equipment design,steady-state simulation and optimization.Many famous engineering and manufacturing companies of chemical engineering,petro-chemical industry and%Aspen Plus是生产装置设计、稳态模拟和优化的大型通用流程模拟系统。全球各大化工、石化、炼油等过程工业制造企业及著名的工程公司都是Aspen Plus的用户。举例介绍了Aspen Plus模拟在氟化工中的应用,分析可能存在的困难,并展望Aspen Plus模拟在氟化工中的应用前景。

  19. Elevated Rocky Mountain elk numbers prevent positive effects of fire on quaking aspen (Populus tremuloides) recruitment

    Science.gov (United States)

    Smith, David Solance; Fettig, Stephen M.; Bowker, Matthew A.

    2016-01-01

    Quaking aspen (Populus tremuloides) is the most widespread tree species in North America and has supported a unique ecosystem for tens of thousands of years, yet is currently threatened by dramatic loss and possible local extinctions. While multiple factors such as climate change and fire suppression are thought to contribute to aspen’s decline, increased browsing by elk (Cervus elaphus), which have experienced dramatic population increases in the last ∼80 years, may severely inhibit aspen growth and regeneration. Fires are known to favor aspen recovery, but in the last several decades the spatial scale and intensity of wildfires has greatly increased, with poorly understood ramifications for aspen growth. Here, focusing on the 2000 Cerro Grande fire in central New Mexico – one of the earliest fires described as a “mega-fire” - we use three methods to examine the impact of elk browsing on aspen regeneration after a mega-fire. First, we use an exclosure experiment to show that aspen growing in the absence of elk were 3× taller than trees growing in the presence of elk. Further, aspen that were both protected from elk and experienced burning were 8.5× taller than unburned trees growing in the presence of elk, suggesting that the combination of release from herbivores and stimulation from fire creates the largest aspen growth rates. Second, using surveys at the landscape level, we found a correlation between elk browsing intensity and aspen height, such that where elk browsing was highest, aspen were shortest. This relationship between elk browsing intensity and aspen height was stronger in burned (r = −0.53) compared to unburned (r = −0.24) areas. Third, in conjunction with the landscape-level surveys, we identified possible natural refugia, microsites containing downed logs, shrubs etc. that may inhibit elk browsing by physically blocking aspen from elk or by impeding elk’s ability to move through the forest patch. We did not find any

  20. Plantation forests, climate change and biodiversity

    Science.gov (United States)

    S.M. Pawson; A. Brin; E.G. Brockerhoff; D. Lamb; T.W. Payn; A. Paquette; J.A. Parrotta

    2013-01-01

    Nearly 4 % of the world’s forests are plantations, established to provide a variety of ecosystem services, principally timber and other wood products. In addition to such services, plantation forests provide direct and indirect benefits to biodiversity via the provision of forest habitat for a wide range of species, and by reducing negative impacts on natural forests...

  1. Plantation forests and biodiversity: oxymoron or opportunity?

    Science.gov (United States)

    Eckehard G. Brockerhoff; Hervé Jactel; John A. Parrotta; Christopher Quine; Jeffrey Sayer

    2008-01-01

    Losses of natural and semi-natural forests, mostly to agriculture, are a significant concern for biodiversity. Against this trend, the area of intensively managed plantation forests increases, and there is much debate about the implications for biodiversity. We provide a comprehensive review of the function of plantation forests as habitat compared with other land...

  2. Plantation agriculture in the tropics - environmental issues

    NARCIS (Netherlands)

    Hartemink, A.E.

    2005-01-01

    Plantation agriculture is more than 400 years old and contributes to the regional and national economies in many tropical countries. This paper reviews some of the main environmental issues related to plantation agriculture with perennial crops, including soil erosion, soil fertility decline, pollut

  3. Reconciling divergent interpretations of quaking aspen decline on the northern Colorado Front Range.

    Science.gov (United States)

    Kashian, Daniel M; Romme, William H; Regan, Claudia M

    2007-07-01

    Ecologists have debated over the past 65 years whether quaking aspen (Populus tremuloides Michx.) has or has not declined in abundance, vigor, or regeneration in western North America. Many studies have provided divergent interpretations of the condition of aspen forests, leading to difficulty in translating this ecological information into management recommendations. To reconcile these contrasting conclusions and to test the hypothesis that multiple types of aspen decline and persistence occur simultaneously on heterogeneous landscapes, we assessed 91 aspen stands across the northern Colorado Front Range to determine the range of ecological conditions that underlie aspen decline or persistence. Approximately 15% of aspen forest area in our sample exhibited dieback of mature stems coupled with a lack of young trees indicative of declining stands, most often at lower elevations where elk browsing is heavy and chronic, and where effects of fire exclusion have been most significant. However, 52% of the area sampled had multiple cohorts indicative of self-replacing or persistent stands. Conifer dominance was increasing in over 33% of all aspen forest area sampled, most often at high elevations among lodgepole pine (Pinus contorta var. latifolia Englem. ex Wats.) forests. Reconstructions of relative basal area and density of aspen and lodgepole pine in these stands suggest cyclical dominance of these species, where conifers gradually replace aspen over long fire intervals, and aspen vigorously re-establish following stand-replacing fires. The diversity of ecological contexts across the northern Colorado Front Range creates a variety of aspen dynamics leading to decline or persistence, and no single trend describes the general condition of aspen forests in appropriate detail for managers. Active management may be useful in preserving individual stands at fine scales, but management prescriptions should reflect specific drivers of decline in these stands.

  4. Sap flux in pure aspen and mixed aspen-birch forests exposed to elevated concentrations of carbon dioxide and ozone.

    Science.gov (United States)

    Uddling, Johan; Teclaw, Ronald M; Kubiske, Mark E; Pregitzer, Kurt S; Ellsworth, David S

    2008-08-01

    Elevated concentrations of atmospheric carbon dioxide ([CO2]) and tropospheric ozone ([O3]) have the potential to affect tree physiology and structure and hence forest water use, which has implications for climate feedbacks. We investigated how a 40% increase above ambient values in [CO2] and [O3], alone and in combination, affect tree water use of pure aspen and mixed aspen-birch forests in the free air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). Measurements of sap flux and canopy leaf area index (L) were made during two growing seasons, when steady-state L had been reached after more than 6 years of exposure to elevated [CO2] and [O3]. Maximum stand-level sap flux was not significantly affected by elevated [O3], but was increased by 18% by elevated [CO2] averaged across years, communities and O(3) regimes. Treatment effects were similar in pure aspen and mixed aspen-birch communities. Increased tree water use in response to elevated [CO2] was related to positive CO2 treatment effects on tree size and L (+40%). Tree water use was not reduced by elevated [O3] despite strong negative O3 treatment effects on tree size and L (-22%). Elevated [O3] predisposed pure aspen stands to drought-induced sap flux reductions, whereas increased tree water use in response to elevated [CO2] did not result in lower soil water content in the upper soil or decreasing sap flux relative to control values during dry periods. Maintenance of soil water content in the upper soil in the elevated [CO2] treatment was at least partly a function of enhanced soil water-holding capacity, probably a result of increased organic matter content from increased litter inputs. Our findings that larger trees growing in elevated [CO2] used more water and that tree size, but not maximal water use, was negatively affected by elevated [O3] suggest that the long-term cumulative effects on stand structure may be more important than the expected primary stomatal closure responses to

  5. Using Aspen plus in thermodynamics instruction a step-by-step guide

    CERN Document Server

    Sandler, Stanley I

    2015-01-01

    A step-by-step guide for students (and faculty) on the use of Aspen in teaching thermodynamics Used for a wide variety of important engineering tasks, Aspen Plus software is a modeling tool used for conceptual design, optimization, and performance monitoring of chemical processes. After more than twenty years, it remains one of the most popular and powerful chemical engineering simulation programs used both industrially and academically. Using Aspen Plus in Thermodynamics Instruction: A Step by Step Guide introduces the reader to the use of Aspen Plus in courses in thermodynamics. It prov

  6. PERACETIC ACID PRETREATMENT OF ALFALFA STEM AND ASPEN BIOMASS

    Directory of Open Access Journals (Sweden)

    Lei Xu,

    2011-11-01

    Full Text Available Alfalfa stems and ground aspen were exposed to peracetic acid (0.5 to 9% on biomass at temperatures ranging from 40 to 100° C and reaction times from 1 to 5 hours. Glucose release as a percentage of total cellulose content was determined using subsequent standard enzymatic hydrolysis. Statistical analysis confirmed that aspen showed a strong response to peracetic acid addition rate. 9% peracetic acid removed 14% of the original lignin and increased the rate of glucose release from 23% to 44%. Temperature and reaction time played a less significant role. For alfalfa stems, low levels of peractic acid (0.5% increased glucose release from 30 to 47%. The addition of larger doses of peracetic acid did not show any significant improvement; this effect appears to be closely related to rate of lignin removal. While peracetic acid effectively removed lignin from aspen, 98% of the original lignin was still present in alfalfa after higher level peracetic acid treatments; the yield loss observed during pretreatment of alfalfa stems originates from other biomass components.

  7. Analysis of Cryogenic Cycle with Process Modeling Tool: Aspen HYSYS

    Science.gov (United States)

    Joshi, D. M.; Patel, H. K.

    2015-10-01

    Cryogenic engineering deals with the development and improvement of low temperature techniques, processes and equipment. A process simulator such as Aspen HYSYS, for the design, analysis, and optimization of process plants, has features that accommodate the special requirements and therefore can be used to simulate most cryogenic liquefaction and refrigeration processes. Liquefaction is the process of cooling or refrigerating a gas to a temperature below its critical temperature so that liquid can be formed at some suitable pressure which is below the critical pressure. Cryogenic processes require special attention in terms of the integration of various components like heat exchangers, Joule-Thompson Valve, Turbo expander and Compressor. Here, Aspen HYSYS, a process modeling tool, is used to understand the behavior of the complete plant. This paper presents the analysis of an air liquefaction plant based on the Linde cryogenic cycle, performed using the Aspen HYSYS process modeling tool. It covers the technique used to find the optimum values for getting the maximum liquefaction of the plant considering different constraints of other parameters. The analysis result so obtained gives clear idea in deciding various parameter values before implementation of the actual plant in the field. It also gives an idea about the productivity and profitability of the given configuration plant which leads to the design of an efficient productive plant.

  8. Foliar bacterial communities of trembling aspen in a common garden.

    Science.gov (United States)

    Mason, Charles J; Pfammatter, Jesse A; Holeski, Liza M; Raffa, Kenneth F

    2015-02-01

    Microbial associations with plants are widely distributed and are structured by a number of biotic and physical factors. Among biotic factors, the host plant genotype may be integral to these plant-microbe interactions. Trees in the genus Populus have become models for studies in scaling effects of host plant genetics and in plant-microbe interactions. Using 454 pyrosequencing of the 16S rRNA gene, we assessed the foliar bacterial community of 7 genotypes of mature trembling aspen trees (Populus tremuloides Michx.) grown in a common garden. Trees were selected based on prior analyses showing clonal variation in their concentration of chemicals conferring resistance against insect herbivores. At broad taxonomic designations, the bacterial community of trembling aspen was similar across all plant genotypes. At a finer taxonomic scale, the foliage of these trees varied in their community composition, but there was no distinct pattern to colonization or abundance related to plant genotype. The most abundant operational taxonomic units (OTUs) were classified as Ralstonia, Bradyrhizobium, Pseudomonas, and Brucella. These OTUs varied across the common garden, but there was no significant effect of host plant genotype or spatial position on the abundance of these members. Our results suggest that aspen genotype is less important in the structuring of its foliar bacterial communities than are other, poorly understood processes.

  9. 2012 Aspen Winter Conferences on High Energy and Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, John; Olivier, Dore; Fox, Patrick; Furic, Ivan; Halkiadakis, Eva; Schmidt, Fabian; Senatore, Leonardo; Smith, Kendrick M; Whiteson, Daniel

    2012-05-01

    Aspen Center for Physics Project Summary DE-SC0007313 Budget Period: 1/1/2012 to 12/31/2012 The Hunt for New Particles, from the Alps to the Plains to the Rockies The 2012 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 11 to February 17, 2012. Sixty-seven participants from nine countries, and several universities and national labs attended the workshop titled, The Hunt for New Particles, from the Alps to the Plains to the Rockies. There were 53 formal talks, and a considerable number of informal discussions held during the week. The weeks events included a public lecture-Hunting the Dark Universe given by Neal Weiner from New York University) and attended by 237 members of the public, and a physics cafe geared for high schoolers that is a discussion with physicists conducted by Spencer Chang (University of Oregon), Matthew Reece (Harvard University) and Julia Shelton (Yale University) and attended by 67 locals and visitors. While there were no published proceedings, some of the talks are posted online and can be Googled. The workshop was organized by John Campbell (Fermilab), Patrick Fox (Fermilab), Ivan Furic (University of Florida), Eva Halkiadakis (Rutgers University) and Daniel Whiteson (University of California Irvine). Additional information is available at http://indico.cern.ch/conferenceDisplay.py?confId=143360. Inflationary Theory and its Confrontation with Data in the Planck Era The 2012 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was Inflationary Theory and its Confrontation with Data in the Planck Era. It was held from January 30 to February 4, 2012. The 62 participants came from 7 countries and attended 43 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists

  10. Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

    Science.gov (United States)

    Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

    2016-06-01

    Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

  11. Ecosystem-based greenhouse budgets in oil palm plantations differ with plantation age

    Science.gov (United States)

    Meijide, Ana; Hassler, Evelyn; Corre, Marife D.; June, Tania; Veldkamp, Edzo; Knohl, Alexander

    2016-04-01

    Global increase in demand of palm oil is leading to the expansion of oil palm plantations, particularly in SE Asia. Oil palm plantations in Sumatra, Indonesia, together with those in Kalimantan, are responsible for half of the world's palm oil production. Available studies point to plantations being large carbon dioxide (CO2) sinks due to the high photosynthetic rates of oil palm as a result of high fertilizer inputs, especially in large-scale plantations. However, methane (CH4) uptake in the soil of oil palm plantations is reduced and soil nitrous oxide (N2O) emissions increased right after nitrogen (N) fertilization. Greenhouse gas (GHG) budgets at the ecosystem level are still missing, and the few available information was derived from mature plantations, pointing to a lack of knowledge on the changes of these GHG budgets with plantation age. With the aim of quantifying CO2, CH4 and N2O fluxes during the non-productive and productive phases of oil palm cultivation, an eddy covariance (EC) tower was installed in a 2-year old (non-productive) oil palm plantation and was subsequently moved to a 12-year old (productive) plantation. Both sites were on Acrisol soils and were located in Jambi province, Sumatra. Chamber-based measurements of soil GHG fluxes were also carried out along the EC footprint. Net ecosystem exchange (NEE), based on EC measurement, showed that the non-productive plantation was a strong CO2 source (990 g C m-2 yr-1) whereas the productive plantation was a CO2 sink (-790 g C m-2 yr-1). For CH4 fluxes, both plantations showed similar soil CH4 uptake that led to a small carbon sink of (~1.3 g C m-2 yr-1). Soil N2O fluxes were high in the productive plantation (3.26 ± 1.73 kg N ha-1 yr-1), as measurements were carried out in a plantation with high fertilization rates. In the non-productive plantation, soil N2O fluxes were lower and were associated with fertilization events. Our results show that the global warming potential of a non-productive oil

  12. Aspen Plus在循环冷却水系统中的应用%Application of Aspen Plus in Circulating Cooling Water System

    Institute of Scientific and Technical Information of China (English)

    朱丽华; 李波

    2016-01-01

    Aspen Plus是一个生产装置设计、稳态模拟和优化的大型通用流程模拟系统.基于此,综述Aspen Plus在换热网络中的应用,并且利用Aspen Plus模拟了换热器的换热过程,同时也模拟了污垢对换热器的影响,为优化循环冷却水系统提供了一种新的方法.

  13. Aspen Plus软件在烟气脱硫系统中的应用%Application of Aspen Plus Software in Flue Gas Desulfuration System

    Institute of Scientific and Technical Information of China (English)

    陈茂兵; 缪明烽; 卢作基

    2011-01-01

    介绍了Aspen Plus软件的概况,系统地阐述了Aspen Plus在湿法脱硫工艺系统中应用,详细介绍了Aspen Plus在湿法脱硫FGD系统中的吸收塔、换热器、泵等关键设备设计,开发、选型中的应用,以及模型分析工具在工艺参数优化、降低工程造价中的应用.

  14. Recovering aspen follow changing elk dynamics in Yellowstone: evidence of a trophic cascade?

    Science.gov (United States)

    Painter, Luke E; Beschta, Robert L; Larsen, Eric J; Ripple, William J

    2015-01-01

    To investigate the extent and causes of recent quaking aspen (Populus tremuloides) recruitment in northern Yellowstone National Park, we measured browsing intensity and height of young aspen in 87 randomly selected aspen stands in 2012, and compared our results to similar data collected in 1997-1998. We also examined the relationship between aspen recovery and the distribution of Rocky Mountain elk (Cervus elaphus) and bison (Bison bison) on the Yellowstone northern ungulate winter range, using ungulate fecal pile densities and annual elk count data. In 1998, 90% of young aspen were browsed and none were taller-than 200 cm, the height at which aspen begin to escape from elk browsing. In 2012, only 37% in the east and 63% in the west portions of the winter range were browsed, and 65% of stands in the east had young aspen taller than 200 cm. Heights of young aspen were inversely related to browsing intensity, with the least browsing and greatest heights in the eastern portion of the range, corresponding with recent changes in elk density and distribution. In contrast with historical elk distribution (1930s-1990s), the greatest densities of elk recently (2006-2012) have been north of the park boundary (approximately 5 elk/km2), and in the western part of the range (2-4 elk/km2), with relatively few elk in the eastern portion of the range (aspen stands have begun to recover. Increased predation pressure following the reintroduction of gray wolves (Canis lupius) in 1995-1996 played a role in these changing elk population dynamics, interacting with other influences including increased predation by bears (Ursus spp.), competition with an expanding bison population, and shifting patterns of human land use and hunting outside the park. The resulting new aspen recruitment is evidence of a landscape-scale trophic cascade in which a resurgent large carnivore community, combined with other ecological changes, has benefited aspen through effects on ungulate prey.

  15. Obstacles for Plantation to Get FSC Certification in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The development of plantation plays a very important role in forestry industry development in China because of its unique advantages. However, the ecological and environmental issues urgently require sustainable plantation development. FSC certification for sustainable forest management balances the economic, environmental and social benefits and contributes to sustainable development of plantation. FSC certification for plantation is significantly important to China with the most plantation area in the wor...

  16. Transition to an IP Environment. A Report of the Annual Aspen Institute Conference on Telecommunications Policy (15th, Aspen, Colorado, August 12-16, 2000) with Thoughts on the Implications of Technological Change for Telecommunications Policy.

    Science.gov (United States)

    Entman, Robert M.; Katz, Michael L.

    The Aspen Institute's Communications and Society Program convened leaders and experts in the telecommunications and related fields to address telecommunications regulation in an IP (Internet Protocols) environment at the 15th annual Aspen Institute Telecommunications Policy Conference (Aspen, Colorado, August 12-16, 2000). The report from this…

  17. Using user models in Matlab® within the Aspen Plus® interface with an Excel® link

    OpenAIRE

    Javier Fontalvo Alzate

    2014-01-01

    Process intensification and new technologies require tools for process design that can be integrated into well-known simulation software, such as Aspen Plus®. Thus, unit operations that are not included in traditional Aspen Plus software packages can be simulated with Matlab® and integrated within the Aspen Plus interface. In this way, the user can take advantage of all of the tools of Aspen Plus, such as optimization, sensitivity analysis and cost estimation. This paper gives a detailed desc...

  18. 77 FR 10491 - City of Aspen; Notice of Intent To File License Application, Filing of Pre-Application Document...

    Science.gov (United States)

    2012-02-22

    ... Energy Regulatory Commission City of Aspen; Notice of Intent To File License Application, Filing of Pre....: 13254-002. c. Date Filed: December 12, 2011. d. Submitted By: City of Aspen. e. Name of Project: Castle Creek Hydroelectric Project. f. Location: On Maroon and Castle Creeks near the City of Aspen, in...

  19. Factors influencing epiphytic lichen communities in aspen-associated forests of the Bear River Range, Idaho and Utah

    Science.gov (United States)

    Paul C. Rogers

    2007-01-01

    In western North America, quaking aspen (Populus tremuloides Michx.) is the most common hardwood in montane landscapes. Fire suppression, grazing, wildlife management practices, and climate patterns of the past century are some of the threats to aspen coverage in this region. Researchers are concerned that aspen-dependent species may be losing...

  20. Aspen increase soil moisture, nutrients, organic matter and respiration in Rocky Mountain forest communities.

    Science.gov (United States)

    Buck, Joshua R; St Clair, Samuel B

    2012-01-01

    Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlake National Forest, Utah, USA. Soil measurements were collected in adjacent forest stands that were characterized as aspen dominated, mixed, conifer dominated or open meadow, which includes the range of vegetation conditions that exist in seral aspen forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than mixed and conifer dominated stands and meadows. Specifically, total N, NO(3) and NH(4) were nearly two-fold higher in soil underneath aspen dominated stands. Soil moisture was significantly higher in aspen stands and meadows in early summer but converged to similar levels as those found in mixed and conifer dominated stands in late summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. These results suggest that changes in disturbance regimes or climate scenarios that favor conifer expansion or loss of aspen will decrease soil resource availability, which is likely to have important feedbacks on plant community development.

  1. Predicting nest success from habitat features in aspen forests of the central Rocky Mountains

    Science.gov (United States)

    Heather M. Struempf; Deborah M. Finch; Gregory Hayward; Stanley Anderson

    2001-01-01

    We collected nesting data on bird use of aspen stands in the Routt and Medicine Bow National Forests between 1987 and 1989. We found active nest sites of 28 species of small nongame birds on nine study plots in undisturbed aspen forests. We compared logistic regression models predicting nest success (at least one nestling) from nest-site or stand-level habitat...

  2. Differential response of Aspen and Birch trees to heat stress under elevated carbon dioxide

    Science.gov (United States)

    Joseph N.T. Darbah; Thomas D. Sharkey; Carlo Calfapietra; David F. Karnosky

    2010-01-01

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO2 and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO2 protected photosynthesis of both species against moderate heat stress. Elevated CO...

  3. A synthetic sex pheromone for the large aspen tortrix in Alaska.

    Science.gov (United States)

    Richard A. Werner; J. Weatherston

    1980-01-01

    Cis-11-tetradecenal was found to be the specific attractant for adult male large aspen tortrix, Choristoneura conflictana (Walker), populations in quaking aspen, Populus tremuloides Michx., forests of interior Alaska. The attractant was dispersed from polyethylene caps in Pherocon® -2 traps placed 1.5 m above ground.

  4. Differential response of aspen and birch trees to heat stress under elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Darbah, Joseph N.T., E-mail: darbah@ohio.ed [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States); Department of Environmental and Plant Biology, Ohio University, 315 Porter Hall, Athens, OH 45701 (United States); Sharkey, Thomas D. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Calfapietra, Carlo [Institute of Agro-Environmental and Forest Biology (IBAF), National Research Council (CNR), Via Salaria km 29300, 00016 Monterotondo Scalo, Roma (Italy); Karnosky, David F. [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States)

    2010-04-15

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO{sub 2} and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO{sub 2} protected photosynthesis of both species against moderate heat stress. Elevated CO{sub 2} increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 deg. C) decreased all of these parameters in birch regardless of CO{sub 2} treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO{sub 2} were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO{sub 2}. Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms. - We report that elevated CO{sub 2} confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.

  5. Simulation of Quaking Aspen Potential Fire Behavior in Northern Utah, USA

    Directory of Open Access Journals (Sweden)

    R. Justin DeRose

    2014-12-01

    Full Text Available Current understanding of aspen fire ecology in western North America includes the paradoxical characterization that aspen-dominated stands, although often regenerated following fire, are “fire-proof”. We tested this idea by predicting potential fire behavior across a gradient of aspen dominance in northern Utah using the Forest Vegetation Simulator and the Fire and Fuels Extension. The wind speeds necessary for crowning (crown-to-crown fire spread and torching (surface to crown fire spread were evaluated to test the hypothesis that predicted fire behavior is influenced by the proportion of aspen in the stand. Results showed a strong effect of species composition on crowning, but only under moderate fire weather, where aspen-dominated stands were unlikely to crown or torch. Although rarely observed in actual fires, conifer-dominated stands were likely to crown but not to torch, an example of “hysteresis” in crown fire behavior. Results support the hypothesis that potential crown fire behavior varies across a gradient of aspen dominance and fire weather, where it was likely under extreme and severe fire weather, and unlikely under moderate and high fire weather. Furthermore, the “fire-proof” nature of aspen stands broke down across the gradient of aspen dominance and fire weather.

  6. Response of transplanted aspen to irrigation and weeding on a Colorado reclaimed surface coal mine

    Science.gov (United States)

    Robert C. Musselman; Wayne D. Shepperd; Frederick W. Smith; Lance A. Asherin; Brian W. Gee

    2012-01-01

    Successful re-establishment of aspen (Populus tremuloides Michx.) on surface-mined lands in the western United States is problematic because the species generally regenerates vegetatively by sprouting from parent roots in the soil; however, topsoil is removed in the mining process. Previous attempts to plant aspen on reclaimed mine sites have failed because...

  7. Aspen indicator species in lichen communities in the Bear River range of Idaho and Utah

    Science.gov (United States)

    Paul C. Rogers; Roger Rosentreter; Ronald J. Ryel

    2007-01-01

    Aspen are thought to be declining in this region due to a combination of fire suppression, grazing and wildlife management practices, and potentially cool/wet climates of the past century which favor advancing conifer succession. Many scientists are concerned that aspen's related species may also be losing habitat, thereby threatening the long-term local and...

  8. Application of Aspen Plus in the Course of Chemical Engineering Principle%Aspen Plus软件在化工原理教学中的应用

    Institute of Scientific and Technical Information of China (English)

    张春勇; 郑纯智; 汪斌; 张国华; 文颖频; 张纪霞

    2010-01-01

    化工原理是一门内容广、实践性强的课程.为了培养学生的工程实践能力,将Aspen Plus软件应用于化工原理教学.介绍了Aspen Plus软件在化工原理教学中的应用,论述了将Aspen Plus软件强大的参数化建模功能应用于教学过程.将Aspen Plus引入到化工原理教学中,有助于学生对化工原理的理解,有助于学生学习兴趣的提高.

  9. Aspen Plus 8.0在精馏设计中的应用%The Application of Aspen Plus 8.0 in Distillation Design

    Institute of Scientific and Technical Information of China (English)

    薛科创; 闫晓前

    2014-01-01

    作为21世纪的化工人才,不但要懂得化工设计,而且要会使用电脑软件进行设计.Aspen Plus作为化工设计的首选软件,尤其是Aspen Plus 8.0以其新特点,得到了众多化工爱好者的青睐.本文以Aspen Plus 8.0在精馏设计中的应用为例,介绍了Aspen Plus 8.0在化工设计中的步骤和方法,为我们进行化工设计和原有工艺改进提供了方法.

  10. Solid Wood Products from Eucalypts Plantations

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    To improve and diversify the use of tropical plantation timbers in Southern China, with support from International Tropical Timber Organizations (ITTO), a research project was started in 2002 focusing on development of processing and manufacturing technologies to promote production of value-added wood products from eucalypts plantations. This project will also facilitate the formulation of forest management strategy in China to supplement the diminishing supply of timber from the natural forests. The sp...

  11. 某化工系统流程的Aspen Plus软件模拟分析%Simulation Analysis with Aspen Plus for a Chemical System Process

    Institute of Scientific and Technical Information of China (English)

    孙立娟; 王佳; 齐鹏

    2015-01-01

    利用Aspen Plus软件对某化工系统流程模拟,并查看各物流结果.应用实例表明,在化工生产中应用Aspen Plus软件可以优化生产,对设备和整套生产装置的操作参数进行模拟,从而实现装置设计优化.

  12. Malaria-associated rubber plantations in Thailand.

    Science.gov (United States)

    Bhumiratana, Adisak; Sorosjinda-Nunthawarasilp, Prapa; Kaewwaen, Wuthichai; Maneekan, Pannamas; Pimnon, Suntorn

    2013-01-01

    Rubber forestry is intentionally used as a land management strategy. The propagation of rubber plantations in tropic and subtropic regions appears to influence the economical, sociological and ecological aspects of sustainable development as well as human well-being and health. Thailand and other Southeast Asian countries are the world's largest producers of natural rubber products; interestingly, agricultural workers on rubber plantations are at risk for malaria and other vector-borne diseases. The idea of malaria-associated rubber plantations (MRPs) encompasses the complex epidemiological settings that result from interactions among human movements and activities, land cover/land use changes, agri-environmental and climatic conditions and vector population dynamics. This paper discusses apparent issues pertaining to the connections between rubber plantations and the populations at high risk for malaria. The following questions are addressed: (i) What are the current and future consequences of rubber plantations in Thailand and Southeast Asia relative to malaria epidemics or outbreaks of other vector-borne diseases? (ii) To what extent is malaria transmission in Thailand related to the forest versus rubber plantations? and (iii) What are the vulnerabilities of rubber agricultural workers to malaria, and how contagious is malaria in these areas?

  13. Drought characteristics' role in widespread aspen forest mortality across Colorado, USA.

    Science.gov (United States)

    Anderegg, Leander D L; Anderegg, William R L; Abatzoglou, John; Hausladen, Alexandra M; Berry, Joseph A

    2013-05-01

    Globally documented widespread drought-induced forest mortality has important ramifications for plant community structure, ecosystem function, and the ecosystem services provided by forests. Yet the characteristics of drought seasonality, severity, and duration that trigger mortality events have received little attention despite evidence of changing precipitation regimes, shifting snow melt timing, and increasing temperature stress. This study draws upon stand level ecohydrology and statewide climate and spatial analysis to examine the drought characteristics implicated in the recent widespread mortality of trembling aspen (Populus tremuloides Michx.). We used isotopic observations of aspen xylem sap to determine water source use during natural and experimental drought in a region that experienced high tree mortality. We then drew upon multiple sources of climate data to characterize the drought that triggered aspen mortality. Finally, regression analysis was used to examine the drought characteristics most associated with the spatial patterns of aspen mortality across Colorado. Isotopic analysis indicated that aspens generally utilize shallow soil moisture with little plasticity during drought stress. Climate analysis showed that the mortality-inciting drought was unprecedented in the observational record, especially in 2002 growing season temperature and evaporative deficit, resulting in record low shallow soil moisture reserves. High 2002 summer temperature and low shallow soil moisture were most associated with the spatial patterns of aspen mortality. These results suggest that the 2002 drought subjected Colorado aspens to the most extreme growing season water stress of the past century by creating high atmospheric moisture demand and depleting the shallow soil moisture upon which aspens rely. Our findings highlight the important role of drought characteristics in mediating widespread aspen forest mortality, link this aspen die-off to regional climate change

  14. Contrasting the patterns of aspen forest and sagebrush shrubland gross ecosystem exchange in montane Idaho, USA

    Science.gov (United States)

    Fellows, A.; Flerchinger, G. N.; Seyfried, M. S.

    2015-12-01

    We investigated the environmental controls on Gross Ecosystem Exchange (GEE) at an aspen forest and a sagebrush shrubland in southwest Idaho. The two sites were situated within a mosaic of vegetation that included temperate deciduous trees, shrublands, and evergreen conifer trees. The distribution of vegetation was presumably linked to water availability; aspen were located in wetter high-elevations sites, topographic drainages, or near snow drifts. Local temperatures have increased by ~2-3 °C over the past 50 years and less precipitation has arrived as snow. These ongoing changes in weather may impact snow water redistribution, plant-water availability, and plant-thermal stress, with associated impacts on vegetation health and production. We used eddy covariance to measure the exchange of water and carbon dioxide above the two sites and partitioned the net carbon flux to determine GEE. The sagebrush record was from 2003-2007 and the aspen record was from 2007-12. The region experienced a modest-to-severe drought in 2007, with ~73% of typical precipitation. We found that aspen were local "hotspots" for carbon exchange; peak rates of aspen GEE were ~ 60% greater than the peak rates of sagebrush GEE. Light, temperature, and water availability were dominant controls on the seasonality of GEE at both sites. Sagebrush and aspen were dormant during winter, limited by cold temperatures during winter and early spring, and water availability during mid-late summer. The onset of summer drought was typically later in the aspen than in the sagebrush. Drifting snow, lateral water redistribution, or increased rooting depths may have increased water availability in the aspen stand. Seasonal patterns of observed soil moisture and evaporation indicated aspen were rooted to >= 1 m. The sagebrush and aspen both responded strongly to the 2007 drought; peak GEE decreased by ~75%, peak GEE shifted to earlier parts of the year, and mid-summer GEE was decreased. We consider potential

  15. Oil palm plantations fail to support mammal diversity.

    Science.gov (United States)

    Yue, Sam; Brodie, Jedediah F; Zipkin, Elise F; Bernard, Henry

    2015-12-01

    Agricultural expansion is the largest threat to global biodiversity. In particular, the rapid spread of tree plantations is a primary driver of deforestation in hyperdiverse tropical regions. Plantations tend to support considerably lower biodiversity than native forest, but it remains unclear whether plantation traits affect their ability to sustain native wildlife populations, particularly for threatened taxa. If animal diversity varies across plantations with different characteristics, these traits could be manipulated to make plantations more "wildlife friendly." The degree to which plantations create edge effects that degrade habitat quality in adjacent forest also remains unclear, limiting our ability to predict wildlife persistence in mixed-use landscapes. We used systematic camera trapping to investigate mammal occurrence and diversity in oil palm plantations and adjacent forest in Sabah, Malaysian Borneo. Mammals within plantations were largely constrained to locations near native forest; the occurrence of most species and overall species richness declined abruptly with decreasing forest proximity from an estimated 14 species at the forest ecotone to -1 species 2 km into the plantation. Neither tree height nor canopy cover within plantations strongly affected mammal diversity or occurrence, suggesting that manipulating tree spacing or planting cycles might not make plantations more wildlife friendly. Plantations did not appear to generate strong edge effects; mammal richness within forest remained high and consistent up to the plantation ecotone. Our results suggest that land-sparing strategies, as opposed to efforts to make plantations more wildlife-friendly, are required for regional wildlife conservation in biodiverse tropical ecosystems.

  16. Modelling and Simulation of Gas Engines Using Aspen HYSYS

    OpenAIRE

    M. C. Ekwonu; Perry, S.; E. A. Oyedoh

    2013-01-01

    In this paper gas engine model was developed in Aspen HYSYS V7.3 and validated with Waukesha 16V275GL+ gas engine. Fuel flexibility, fuel types and part load performance of the gas engine were investigated. The design variability revealed that the gas engine can operate on poor fuel with low lower heating value (LHV) such as landfill gas, sewage gas and biogas with biogas offering potential integration with bottoming cycles when compared to natural gas. The result of the gas engin...

  17. Modelling and Simulation of Gas Engines Using Aspen HYSYS

    OpenAIRE

    M. C. Ekwonu; Perry, S.; E. A. Oyedoh

    2013-01-01

    In this paper gas engine model was developed in Aspen HYSYS V7.3 and validated with Waukesha 16V275GL+ gas engine. Fuel flexibility, fuel types and part load performance of the gas engine were investigated. The design variability revealed that the gas engine can operate on poor fuel with low lower heating value (LHV) such as landfill gas, sewage gas and biogas with biogas offering potential integration with bottoming cycles when compared to natural gas. The result of the gas engin...

  18. Modelling and Simulation of Gas Engines Using Aspen HYSYS

    Directory of Open Access Journals (Sweden)

    M. C. Ekwonu

    2013-12-01

    Full Text Available In this paper gas engine model was developed in Aspen HYSYS V7.3 and validated with Waukesha 16V275GL+ gas engine. Fuel flexibility, fuel types and part load performance of the gas engine were investigated. The design variability revealed that the gas engine can operate on poor fuel with low lower heating value (LHV such as landfill gas, sewage gas and biogas with biogas offering potential integration with bottoming cycles when compared to natural gas. The result of the gas engine simulation gave an efficiency 40.7% and power output of 3592kW.

  19. Current Situation and Challenges of Plantation Development in China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The area of plantation in China ranks the first in the world. But, many challenges are still faced in the development of China’s plantation. A review of plantation in China was presented and the challenges were analyzed. The plantation features juvenile and middle age class with low diameter at breast height. There are the risks of pests and diseases in plantation, the potential decline in land fertility and bio-diversity, all of which are unfavorable to a healthy development of plantations.

  20. Aspen Ecology in Rocky Mountain National Park: Age Distribution, Genetics, and the Effects of Elk Herbivory

    Science.gov (United States)

    Zeigenfuss, Linda C.; Binkley, Dan; Tuskan, Gerald A.; Romme, William H.; Yin, Tongming; DiFazio, Stephen; Singer, Francis J.

    2008-01-01

    Lack of recruitment and canopy replacement of aspen (Populus tremuloides) stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado have been a cause of concern for more than 70 years. We used a combination of traditional dendrochronology and genetic techniques as well as measuring the characteristics of regenerating and nonregenerating stands on the elk winter range to determine when and under what conditions and estimated elk densities these stands established and through what mechanisms they may regenerate. The period from 1975 to 1995 at low elevation on the east side had 80-95 percent fewer aspen stems than would be expected based on the trend from 1855 through 1965. The age structure of aspen in the park indicates that the interacting effects of fires, elk population changes, and livestock grazing had more-or-less consistent effects on aspen from 1855 to 1965. The lack of a significant change in aspen numbers in recent decades in the higher elevation and west side parts of the park supports the idea that the extensive effects of elk browsing have been more important in reducing aspen numbers than other factors. The genetic variation of aspen populations in RMNP is high at the molecular level. We expected to find that most patches of aspen in the park were composed of a single clone of genetically identical trees, but in fact just 7 percent of measured aspen patches consisted of a single clone. A large frequency of polyploid (triploid and tetraploid) genotypes were found on the low elevation, east-side elk winter range. Nonregenerating aspen stands on the winter range had greater annual offtake, shorter saplings, and lower density of mid-height (1.5-2.5 m) saplings than regenerating stands. Overwinter elk browsing, however, did not appear to inhibit the leader length of aspen saplings. The winter range aspen stands of RMNP appear to be highly resilient in the face of

  1. Conservation and yield aspects of old European aspen Populus tremula L. in Swedish forestry

    Energy Technology Data Exchange (ETDEWEB)

    Hazell, Per [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Management and Products

    1999-06-01

    Biodiversity issues are becoming integrated parts of Swedish forest management. In this context, the amount and distribution of broadleaved species, including aspen, are important. This thesis summarises results of two studies in which species from the rich epiphytic flora on aspen were used to evaluate important features of aspens, and two studies relating these features to production losses due to retention of aspen. The presence and abundance of four epiphytic, bark-living bryophytes in relation to stand and host-tree characteristics, were investigated in four mixed forest stands in central Sweden. There was no general and consistent relation between aspen density and bryophyte presence. Large diameter and rough bark of the aspen host, together with site factors and stand density around the host, were important. On 35 clearfelled areas, the bryophyte Antitrichia curtipendula (Hedw.) Brid. and the lichen Lobaria pulmonaria (L.) Hoffm., species considered sensitive to clearfelling, were transplanted on retained aspen stems. As a reference, transplants were made on aspens in adjacent old stands. After two years the bryophyte showed its highest vitality in the forest, but was also vigorous on the north side of retained trees. The lichen thrived best on the clearfelled areas, on the north side of trees retained in groups. For conservation purposes, aspen are best retained in groups. Qualitative and quantitative aspects of retained large aspens (diameter 49.6{+-}7.0 cm and height 29.4{+-}1.0 m) were studied in a 110-year-old aspen stand. Twelve trees were destructively analysed to establish allometric equations relating stem, bark and branch biomass and current annual stem increment (CAI{sub s}) to diameter at breast height. Biomass of the mean tree was 1172 kg, of which 80% was stemwood. CAI{sub s} was 1.5% of total stem biomass. Finally, the yield of a 44-year-old Norway spruce stand under an aspen overstorey was compared with that of pure Norway spruce, estimated

  2. 13C Tracking after 13CO2 Supply Revealed Diurnal Patterns of Wood Formation in Aspen.

    Science.gov (United States)

    Mahboubi, Amir; Linden, Pernilla; Hedenström, Mattias; Moritz, Thomas; Niittylä, Totte

    2015-06-01

    Wood of trees is formed from carbon assimilated in the photosynthetic tissues. Determining the temporal dynamics of carbon assimilation, subsequent transport into developing wood, and incorporation to cell walls would further our understanding of wood formation in particular and tree growth in general. To investigate these questions, we designed a (13)CO2 labeling system to study carbon transport and incorporation to developing wood of hybrid aspen (Populus tremula × tremuloides). Tracking of (13)C incorporation to wood over a time course using nuclear magnetic resonance spectroscopy revealed diurnal patterns in wood cell wall biosynthesis. The dark period had a differential effect on (13)C incorporation to lignin and cell wall carbohydrates. No (13)C was incorporated into aromatic amino acids of cell wall proteins in the dark, suggesting that cell wall protein biosynthesis ceased during the night. The results show previously unrecognized temporal patterns in wood cell wall biosynthesis, suggest diurnal cycle as a possible cue in the regulation of carbon incorporation to wood, and establish a unique (13)C labeling method for the analysis of wood formation and secondary growth in trees.

  3. Les Plantations D’alignements En Turquie

    Directory of Open Access Journals (Sweden)

    Metin SARIBAŞ

    2008-01-01

    Full Text Available L’état actuel des forets de Turquie est insuffisant pour les besoins en bois. İl est indispensable de chercher denouvelles alternatives pour enrichir les produits du bois en dehors de la source forestière. Les plantationsd’alignements peuvent etre les ressources assez abondantes.Actuellement les pays qui font les plantations d’alignements sont: France, L’İtalie, Belgique, Pays-Bas,L’Allemange, L’Angleterre, Hongrie, Turquie, Grèce; L’Iraq, L’İran, Au Japonais, Aux Etat-Unis, Au Canada,L’Argentine, Bosna -Herzégovinia, L’Avustralie, Bulgaria etc. Selon les etudes de L’İnstitut Turc de RecherchePeuplier à İzmit en Turquie, longueurs des plantations routières sont aux environs de 64000km. D’aprés Hilf(1953 en France %10; en Angletterre %30 de production du bois était à l’origine des plantations routières.Depuis longtemps on discute des inconvénients et des avantages des plantations d’alignements. A parte quelquesrares exceptions, les plantations sont donc devenues pratique, courante, confiées le plus souvent a des servicesadministratifs et lorsqu’elles ne sont pas rendues obligatoires, encoragées tout au moins par subventions, enargents ou en nature et par exemptions d’impots.Les essences utilisées dans les plantations d’alignements sont: Le Platane, L’Orme, Le Peuplier, Le Frene, LeTilleul, L’Erable, Le Sycomore, Le Robinier, L’Acacia, Le Pavia, Le Noyer, Le Carya, Le Chataigner, L’Aulne,Le Bouleau, Le Chene, Le Hetre, Le Paulownia, Aillanthe, L’Alisier, Le Charme, Le Murrier etc. Dans notrearticle on porrrait étudier le potentiel prochain en détail les plantations d’alignements actuelle et dans l’avenir.

  4. Aspen shaving versus chip bedding: effects on breeding and behavior.

    Science.gov (United States)

    Jackson, E; Demarest, K; Eckert, W J; Cates-Gatto, C; Nadav, T; Cates, L N; Howard, H; Roberts, A J

    2015-01-01

    The choice of laboratory cage bedding material is often based on both practical and husbandry issues, whereas behavioral outcomes rarely appear to be considered. It has been noted that a breeding success difference appears to be associated with the differential use of aspen chip and aspen shaving bedding in our facility; therefore, we sought to analyze breeding records maintained over a 20-month period. In fact, in all four mouse strains analyzed, shaving bedding was associated with a significant increase in average weanlings per litter relative to chip bedding. To determine whether these bedding types also resulted in differences in behaviors associated with wellbeing, we examined nest building, anxiety-like, depressive-like (or helpless-like), and social behavior in mice housed on chip versus shaving bedding. We found differences in the nests built, but no overall effect of bedding type on the other behaviors examined. Therefore, we argue that breeding success, perhaps especially in more challenging strains, is improved on shaving bedding and this is likely due to improved nest-building potential. For standard laboratory practices, however, these bedding types appear equivalent.

  5. Great Plains ASPEN model development: Phosam section. Final topical report

    Energy Technology Data Exchange (ETDEWEB)

    Stern, S S; Kirman, J J

    1985-02-01

    An ASPEN model has been developed of the PHOSAM Section, Section 4600, of the Great Plains Gasification Plant. The bases for this model are the process description given in Section 6.18 of the Great Plains Project Management Plan and the Lummus Phosam Schematic Process Flow Diagram, Dwg. No. SKD-7102-IM-O. The ASPEN model that has been developed contains the complete set of components that are assumed to be in the gasifier effluent. The model is primarily a flowsheet simulation that will give the material and energy balance and equipment duties for a given set of process conditions. The model is unable to predict fully changes in process conditions that would result from load changes on equipment of fixed sizes, such as a rating model would predict. The model can be used to simulate the steady-state operation of the plant at or near design conditions or to design other PHOSAM units. Because of the limited amount of process information that was available, several major process assumptions had to be made in the development of the flowsheet model. Patent literature was consulted to establish the ammonia concentration in the circulating fluid. Case studies were made with the ammonia content of the feed 25% higher and 25% lower than the base feed. Results of these runs show slightly lower recoveries of ammonia with less ammonia in the feed. As expected, the duties of the Stripper and Fractionator reboilers were higher with more ammonia in the feed. 63 references.

  6. Aspen (Populus tremuloides Michx.) intake and preference by mammalian herbivores: the role of plant secondary compounds and nutritional context.

    Science.gov (United States)

    Villalba, Juan J; Burritt, Elizabeth A; St Clair, Samuel B

    2014-10-01

    Aspen (Populus tremuloides Michx.) has evolved a chemical defense system comprised of phenolic glycosides (PG), which effectively deter insect herbivory. However, much less is known about the role of PG and the nutritional quality of the associated plant community on aspen browse susceptibility to mammalian herbivores. In three successive periods during the growing season, we conducted experiments with sheep by offering leaves from two aspen stands with different concentrations of PG (LOW, HIGH) or aspen leaves vs. leaves from a forb (Utah pea, Lathyrus pauciflorus) or a grass (smooth brome, Bromus inermis Leyss.) growing in an aspen understory. Intake of aspen (19 to 35 % PG) was low in all periods (1 to 6 g/Kg(0.75) in 2 hr) supporting the notion that aspen's defense system may contribute to its ecological success. However, lambs ate larger amounts of LOW than of HIGH suggesting that sheep could discriminate between aspen stands with different concentrations of PG, even when both stands were relatively well defended. Concentration of nutrients and chemical defenses in aspen leaves remained fairly stable across the growing season, and preference for aspen increased over the growing season. In contrast, preference for the forb and the grass decreased across the growing season in concert with a decline in the nutritional quality of these plants. The data suggest that nutritional context of aspen and associated forage species drove preference more than contrasts in defense chemistry of aspen. There may be periods of "susceptibility" of aspen use by mammalian herbivores, despite high concentrations of chemical defenses, which can potentially be targeted by management to reduce aspen herbivory.

  7. Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.

    Science.gov (United States)

    Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

    2009-11-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in pure aspen and mixed aspen-birch forests. Our results, together with the findings from other long-term FACE experiments with trees, suggest that model assumptions of large reductions in stomatal conductance under rising atmospheric CO2 are very uncertain for forests.

  8. The Application of Aspen Plus Simulation in Chemical Industry%Aspen Plus在化工中的应用

    Institute of Scientific and Technical Information of China (English)

    张治山; 杨超龙

    2012-01-01

    Aspen Plus是基于稳态化工模拟、优化、灵敏度分析和经济评价的大型化工流程模拟软件,其广泛应用于化学与石油工业、炼油加工、生物及医药等方面。文章介绍了该软件的功能特点,综述了近几年来该流程模拟软件在化工工程中的应用成果及发展情况。%Aspen Plus is based on the steady-state chemical simulation, optimization, sensitivity analysis and economic evaluation of large-scale chemical process simulation software, which is widely used in chemistry and petroleum industry, oil refining process, biology and medicine and so on. The function characteristics of the software were introduced in the paper, the application results and the development situation of chemical process simulation software on process in recent years are summarized.

  9. Biological processes as indicators of sustainable plantation forestry ...

    African Journals Online (AJOL)

    Biological processes as indicators of sustainable plantation forestry : evidence for sustainable plantation forestry. ... may be useful in the sustainable management of nutrient cycling, yield production, pest outbreaks and water use and quality.

  10. Inventory of aspen trees in spruce dominated stands in conservation area

    Directory of Open Access Journals (Sweden)

    Matti Maltamo

    2015-05-01

    Full Text Available Background The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes: volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning (ALS data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50% with fewer sample plots (5–10 to values of 25%–50% with 10 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our

  11. Inventory of aspen trees in spruce dominated stands in conservation area

    Institute of Scientific and Technical Information of China (English)

    Matti Maltamo; Annukka Pesonen; Lauri Korhonen; Jari Kouki; Mikko Vehmas; Kalle Eerikinen

    2015-01-01

    Background:The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods:We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes:volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning (ALS) data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results:The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50%with fewer sample plots (5–10) to values of 25%–50%with 10 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions:This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our results suggest that

  12. Hemipteran diversity in Endau-Rompin plantation

    Science.gov (United States)

    Bakri, Asraf; Rahim, Faszly

    2015-09-01

    Study on hemipteran at Endau Rompin Plantation (LER), Pahang was conducted at oil palm plantation planted at different type of soils. The aim of the study was to determine hemipteran diversity in oil palm ecosystem. Sampling was done from April 2012 to September 2012 by using Malaise and impact traps. Cicadellidae was the most abundance and dominance family with 105 individuals and 6 species (=morphospecies) recorded. The rarefaction curve becomes flatter to the right indicating a reasonable number of individual samples have been taken. Peat area show high Shannon index and Margalef index values compared to clay area.There were significant differences in hemipteran community between three type of soils (χ2=98.751,df=58,p<0.05). As such, hemipteran abundance in oil palm plantation is affected by the type of soil.

  13. Nitrogen supply and demand in short-rotation sweetgum plantations

    Science.gov (United States)

    D. Andrew Scott; James A. Burger; Donald J. Kaczmarek; Michael B. Kane

    2004-01-01

    Intensive management is crucial for optimizing hardwood plantation success, and nitrogen (N) nutrition management is one of the most important practices in intensive management. Because management of short-rotation woody crop plantations is a mixture of row-crop agriculture and plantation forestry, we tested the usefulness of an agronomic budget modified for deciduous...

  14. Current Status and Advancements in Research of Plantation Nutrient Cycling

    Institute of Scientific and Technical Information of China (English)

    LI Run; ZHANG Changshun; SUN Yongyu

    2006-01-01

    This paper introduces concepts and current research status of plantation nutrients cyclings, and analyzes main contents of plantation nutrients cycling as nutrients contents, accumulation and distribution of nutrients elements, understory species and forest litter. At the same time, the paper summarizes the problems in plantation nutrients cycling and its prospects.

  15. 基于Aspen Plus的克劳斯硫回收过程模拟%Analog of ClausSulfur Recovery Process Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    林发现; 丁玲; 陈延林; 李繁荣; 师慧灵; 邹隐文

    2011-01-01

    Adopting Aspen Plus process analog calculation software,process flow for Claus sulfur recovery was simulated,simulated data was good coincident with the data demarcated by analog software used specially for sulfur recovery;on that basis,author has studied the influence of Claus key data on process flow by use of Aspen Plus modular analysis function,its conclusion was coincident with practical production process;result indicates that it has optimizing role for both design calculation and production operation based on the Claus sulfur recovery process analog.%采用Aspen P lus工艺模拟计算软件模拟了克劳斯硫回收工艺过程,模拟数据与硫回收专用模拟软件的标定数据吻合较好;在此基础上,利用Aspen P lus模块化分析功能,研究了克劳斯工艺的关键数据对工艺过程的影响,其结论与实际生产过程相符合;结果表明,基于Aspen P lus的克劳斯硫回收过程模拟,对设计计算和生产操作均具有优化作用。

  16. Gene flow among different taxonomic units: evidence from nuclear and cytoplasmic markers in Cedrus plantation forests.

    Science.gov (United States)

    Fady, B; Lefèvre, F; Reynaud, M; Vendramin, G G; Bou Dagher-Kharrat, M; Anzidei, M; Pastorelli, R; Savouré, A; Bariteau, M

    2003-10-01

    Hybridization and introgression are important natural evolutionary processes that can be successfully investigated using molecular markers and open- and controlled-pollinated progeny. In this study, we collected open-pollinated seeds from Cedrus atlantica, Cedrus libani and C. libani x C. atlantica hybrids from three French-plantation forests. We also used pollen from C. libani and Cedrus brevifolia to pollinate C. atlantica trees. The progeny were analyzed using three different types of molecular markers: RAPDs, AFLPs and cpSSRs. Chloroplast DNA was found to be paternally inherited in Cedrus from the progeny of controlled-crosses. Heteroplasmy, although possible, could not be undoubtedly detected. There was no indication of strong reproductive isolating barriers among the three Mediterranean Cedrus taxa. Gene flow between C. atlantica and C. libani accounted for 67 to 81% of viable open-pollinated seedlings in two plantation forests. We propose that Mediterranean Cedrus taxa should be considered as units of a single collective species comprising two regional groups, North Africa and the Middle East. We recommend the use of cpSSRs for monitoring gene flow between taxa in plantation forests, especially in areas where garden specimens of one species are planted in the vicinity of selected seed-stands and gene-conservation reserves of another species.

  17. 2013 Aspen Winter Conference on particle physics: Higgs Quo Vadis

    CERN Document Server

    2013-01-01

    By winter of 2013, the ATLAS and CMS experiments at the LHC will establish their discovery of a new Higgs-like particle with a mass around 125 GeV. The new data will shed light on its properties. Many fundamental questions in Physics will start to get their answer. The 2013 Aspen Winter Conference on particle physics will bring together experimentalists and theorists, creating an ideal environment to present and discuss the implications of the Higgs discovery in the framework of the Standrad Model and beyond. The conference will be formulated to encourage close collaborations and active exchange of information, which is crucial for making progress on this central topic of particle physics.

  18. Simulation of IGFC power generation system by Aspen Plus

    DEFF Research Database (Denmark)

    Rudra, Souman; Rosendahl, Lasse; Sayem, Abu Sadahat

    2010-01-01

    The solid oxide fuel cell (SOFC) is a promising technology for electricity generation. Sulfur free syngas from the gas cleaning unit serves as a fuel for SOFC in IGFC (Integrated gasification Fuel cell) power plant. It converts the chemical energy of the fuel gas directly to electric energy...... efficiency and power with respect to a variety of SOFC inputs. HRSG which is located after the SOFC is also included in current simulation study with various operating parameters. This paper also describes for the IGFC Power Plants, the optimization of the Heat Recovery Steam Generator (HRSG...... and therefore, very high efficiencies can be achieved. The outputs from SOFC can be utilized by HRSG which drives steam turbine for electricity production. The SOFC stack model developed using the process flow sheet simulator Aspen Plus which is of equilibrium type. The results indicate there must be tread off...

  19. Orbital Express Mission Operations Planning and Resource Management using ASPEN

    Science.gov (United States)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Danny

    2008-01-01

    The Orbital Express satellite servicing demonstrator program is a DARPA program aimed at developing "a safe and cost-effective approach to autonomously service satellites in orbit". The system consists of: a) the Autonomous Space Transport Robotic Operations (ASTRO) vehicle, under development by Boeing Integrated Defense Systems, and b) a prototype modular next-generation serviceable satellite, NEXTSat, being developed by Ball Aerospace. Flexibility of ASPEN: a) Accommodate changes to procedures; b) Accommodate changes to daily losses and gains; c) Responsive re-planning; and d) Critical to success of mission planning Auto-Generation of activity models: a) Created plans quickly; b) Repetition/Re-use of models each day; and c) Guarantees the AML syntax. One SRP per day vs. Tactical team

  20. Best Practices Case Study: Shaw Construction Burlingame Ranch Ph.1, Aspen, CO

    Energy Technology Data Exchange (ETDEWEB)

    Pacific Northwest National Laboratory & Oak Ridge National Laboratory

    2010-12-01

    Shaw Construction built 84 energy efficient, affordable condominiums forthe City of Aspen that achieved HERS scores of less than 62 with help from Building America’s research team lead Building Science Corporation.

  1. Elevated CO2 response of photosynthesis depends on ozone concentration in aspen

    Science.gov (United States)

    Asko Noormets; Olevi Kull; Anu Sober; Mark E. Kubiske; David F. Karnosky

    2010-01-01

    The effect of elevated CO2 and O3 on apparent quantum yield (ø), maximum photosynthesis (Pmax), carboxylation efficiency (Vcmax) and electron transport capacity (Jmax) at different canopy locations was studied in two aspen (Populus...

  2. 78 FR 46312 - Spruce Beetle Epidemic and Aspen Decline Management Response; Grand Mesa, Uncompahgre and...

    Science.gov (United States)

    2013-07-31

    ...-of-way and border zones. Other priority treatment areas may be identified through the analysis and... conditions of spruce-fir and healthy clones of aspen. Removal of single trees or group selections of...

  3. Sorption of copper by chemically modified aspen wood fibers.

    Science.gov (United States)

    Huang, Liyuan; Ou, Zhaoyang; Boving, Thomas B; Tyson, Julian; Xing, Baoshan

    2009-08-01

    Sorption of copper (Cu(2+)) by untreated and treated (bleaching and hydrolysis) aspen wood fibers, cellulose and lignin was examined to understand the Cu(2+) sorption behavior by these natural sorbents. All sorbents were characterized by solid-state (13)C NMR and FTIR. Bleaching broke up aromatic structures and increased hydrophilicity of the fibers, whereas hydrolysis decreased carbohydrate content, producing a more hydrophobic structure. Copper sorption was a function of pH; the percentage of Cu(2+) sorption steadily increased from pH 1.5 to 4.5 with a maximum sorption amount at around pH 5.5 for all the materials. All isotherms fitted well to the Langmuir equation. Bleached sample (BL) had a highest sorption capacity, followed by untreated (UTR), cellulose (CEL), and hydrolyzed (HHY), while lignin (LIG) had little Cu(2+) sorption under the studied conditions. The results suggested that carboxyl (-COOH) and hydroxyl (-CHOH) in carbohydrates are mainly responsible for Cu(2+) sorption, and that ion exchange may be a main sorption mechanism for the studied sorbents. Additionally, the sorption capacity for Cu(2+) on all sorbents decreased with the increase of the initial concentrations of Ca(2+), Na(+) or Al(3+). Copper sorption decreased rapidly at low initial concentrations of Ca(2+), Na(+) or Al(3+). However, the decline of Cu(2+) sorption slowed down when initial Na(+) and Ca(2+) concentration was higher than 0.05M or initial Al(3+) concentration was greater than 0.005M, indicating that specific adsorption may be taking place. Therefore, the majority of sorbed Cu(2+) to aspen wood fibers could be through ion exchange (especially, for UTR, BL and CEL), while a faction of sorbed Cu(2+) via inner-sphere complex (or specific adsorption).

  4. Simulated control in Aspen Dynamics for the production of limonene epoxide at pilot scale

    OpenAIRE

    Yeison Agudelo Arenas; Rolando Barrera Zapata

    2016-01-01

    In this contribution is reported the study and analysis of the control system (simulated) for the process of obtaining limonene epoxide. The modelling of the process at pilot scale was implemented in the software Aspen Plus from literature reports. Aspen Dynamics was used for the study of the process control. The model allows observing the behavior of the variables of interest in the process such as outflows from the distillation tower, heat duty, operating temperaturas and purity of the fina...

  5. The application of Aspen Plus server in software integration%Aspen Plus服务器在软件集成中的应用

    Institute of Scientific and Technical Information of China (English)

    孔祥冰; 岳金彩; 谭心舜; 焦巍

    2007-01-01

    ActiveX控件作为可重复使用的程序和数据可集成到其它应用程序中,Aspen Plus用户界面就是一个ActiveX服务器应用程序,利用接口程序能够将用户对装置模型及其参数的改变传递给Aspen Plus,再把模拟结果与外部应用程序相连接,实现软件集成.本文对Aspen Plus的服务器功能进行了探讨,并介绍了这个功能的详细开发步骤和编写方法,最后给出了一个吸收塔的具体接口实例.

  6. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L..

    Directory of Open Access Journals (Sweden)

    Kathryn M Robinson

    Full Text Available We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  7. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L.).

    Science.gov (United States)

    Robinson, Kathryn M; Ingvarsson, Pär K; Jansson, Stefan; Albrectsen, Benedicte R

    2012-01-01

    We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp) collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  8. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (Populus tremula).

    Science.gov (United States)

    Aalto-Korte, Kristiina; Välimaa, Jarmo; Henriks-Eckerman, Maj-Len; Jolanki, Riitta

    2005-02-01

    Salicyl alcohol or 2-methylolphenol is a well-known allergen in phenol-formaldehyde resins and a strong sensitizer in guinea pigs. There is 1 previous report of allergic contact dermatitis from salicyl alcohol in aspen bark. We describe a second case with concomitant allergy to salicylaldehyde. An elk researcher who had handled leaves from various trees presented with eczema of the hands, face, flexures, trunk and extremities. Patch testing showed sensitivity to salicyl alcohol, salicylaldehyde, balsam of Peru (Myroxylon pereirae resin), aspen wood dust and an extract prepared from the bark of aspen (Populus tremula). Weaker reactions were observed to bark extracts of rowan (Sorbus aucuparia), tea-leaved willow (Salix phylicifolia) and goat willow (Salix caprea). We analysed salicyl alcohol and salicylaldehyde in the bark extracts and found the 2 chemicals in equal amounts, about 0.9 microg/mg in aspen bark and in lower concentrations in rowan and the willows. We did not find either of the chemicals in the test substance of balsam of Peru (Myroxylon pereirae). Besides salicyl alcohol, salicylaldehyde is also recommended to be used to screen for contact allergy to aspen. Both of these chemicals should be tested in forest workers in areas where aspen is growing.

  9. The growth strategies of a global pharmaceutical company: a case study of Aspen Pharmacare Holdings Limited

    Directory of Open Access Journals (Sweden)

    Victoria Margaret Hodgon

    2017-05-01

    Full Text Available Given the rapid and sustained growth of Aspen over the past decade, the main aim of this study is to identify and analyze the growth strategies, adopted by Aspen over the period from 2004 to 2014. The research method used was a descriptive study through a single case study of Aspen by analyzing secondary data in the form of publicly available company reports and presentations, as well as financial results, issued between 2004 and 2014. The study finds that, guided by strategic and visionary leadership, Aspen adopted a number of growth strategies including (i organic growth, as a key factor in creating incremental value for Aspen and its stakeholders, (ii inorganic growth, in the form of carefully planned and well executed acquisitions, aligned to the Group strategy, (iii extending territorial coverage through global expansion, particularly into emerging pharmaceutical countries, and (iv ongoing investment in production capabilities as a means of achieving a strategic advantage. Despite the challenges of intense competition, restrictive legislation, pressure on medicine prices, currency volatility and market specific risks, Aspen has delivered double-digit earnings growth to its shareholders for 16 consecutive years.

  10. Innate and introduced resistance traits in genetically modified aspen trees and their effect on leaf beetle feeding.

    Directory of Open Access Journals (Sweden)

    Joakim Hjältén

    Full Text Available Genetic modifications of trees may provide many benefits, e.g. increase production, and mitigate climate change and herbivore impacts on forests. However, genetic modifications sometimes result in unintended effects on innate traits involved in plant-herbivore interactions. The importance of intentional changes in plant defence relative to unintentional changes and the natural variation among clones used in forestry has not been evaluated. By a combination of biochemical measurements and bioassays we investigated if insect feeding on GM aspens is more affected by intentional (induction Bt toxins than of unintentional, non-target changes or clonal differences in innate plant defence. We used two hybrid wildtype clones (Populus tremula x P. tremuloides and Populus tremula x P. alba of aspen that have been genetically modified for 1 insect resistance (two Bt lines or 2 reduced lignin properties (two lines COMT and CAD, respectively. Our measurements of biochemical properties suggest that unintended changes by GM modifications (occurring due to events in the transformation process in innate plant defence (phenolic compounds were generally smaller but fundamentally different than differences seen among different wildtype clones (e.g. quantitative and qualitative, respectively. However, neither clonal differences between the two wildtype clones nor unintended changes in phytochemistry influenced consumption by the leaf beetle (Phratora vitellinae. By contrast, Bt induction had a strong direct intended effect as well as a post experiment effect on leaf beetle consumption. The latter suggested lasting reduction of beetle fitness following Bt exposure that is likely due to intestinal damage suffered by the initial Bt exposure. We conclude that Bt induction clearly have intended effects on a target species. Furthermore, the effect of unintended changes in innate plant defence traits, when they occur, are context dependent and have in comparison to Bt

  11. Weed Control in Black Walnut Plantations

    Science.gov (United States)

    Calvin F. Bey; Robert D. Williams

    1976-01-01

    Weeds must be controlled for at least 3 years to successfully establish walnut plantations. Whether by cultivating or applying chemicals, a strip or spot 4 feet wide is sufficient the first 2 years, followed by a 6-foot spot or strip for the third and fourth years.

  12. Weed Control Trials in Cottonwood Plantations

    Science.gov (United States)

    R. M. Krinard

    1964-01-01

    Weed control in the first year is essential for establishing a cottonwood plantation, for the young trees can neither survive nor grow well if they must compete with other plants. Once the light and moisture conditions are established in its favor, cottonwood becomes the fastest growing tree in the South.

  13. Harvesting costs and utilization of hardwood plantations

    Science.gov (United States)

    Tim P. McDonald; Bryce J. Stokes

    1994-01-01

    The use of short rotation, intensive culture (SRIC) practices in hardwoods to meet fiber supply needs is becoming increasingly widespread. Total plated area of short rotation hardwood fiber plantations is currently about 22,000 ha (McDonald and Stokes 1993). That figure should certainly to grow in response to public concerns over loss of natural hardwood stands. With...

  14. Economic evaluation of Eucalypt energy plantations

    Science.gov (United States)

    Richard B. Standiford; F. Thomas Ledig

    1983-01-01

    An analysis is made of the break-even price at a 6 percent and 10 percent real interest rate for "intensive" and "minimally managed" scenarios for managing eucalypt energy plantations. The break-even price is greater than the average stumpage price reported for firewood and chipwood by the State Board of Equalization. However, a conversion surplus...

  15. Predation risk, elk, and aspen: tests of a behaviorally mediated trophic cascade in the Greater Yellowstone Ecosystem.

    Science.gov (United States)

    Winnie, John A

    2012-12-01

    Aspen in the Greater Yellowstone Ecosystem are hypothesized to be recovering from decades of heavy browsing by elk due to a behaviorally mediated trophic cascade (BMTC). Several authors have suggested that wolves interact with certain terrain features, creating places of high predation risk at fine spatial scales, and that elk avoid these places, which creates refugia for plants. This hypothesized BMTC could release aspen from elk browsing pressure, leading to a patchy recovery in places of high risk. I tested whether four specific, hypothesized fine-scale risk factors are correlated with changes in current elk browsing pressure on aspen, or with aspen recruitment since wolf reintroduction, in the Daly Creek drainage in Yellowstone National Park, and near two aspen enclosures outside of the park boundary. Aspen were not responding to hypothesized fine-scale risk factors in ways consistent with the current BMTC hypothesis.

  16. Aspen Plus在化工专业课程教学中的应用%Application of Aspen Plus in the teaching of chemical engineering major

    Institute of Scientific and Technical Information of China (English)

    郑建东; 徐杰; 冯建华; 杨靖

    2016-01-01

    为了培养学生的工程实践能力,将Aspen Plus软件应用于化学工程与工艺专业课程教学.介绍了Aspen Plus软件在课堂教学中的应用,从而提高学生对化工专业课程的理解能力,增强学生的工程意识,有助于学生学习兴趣的提高.

  17. The Application of Aspen Plus in Chemical Engineering Learning%Aspen Plus在化工学习中的应用

    Institute of Scientific and Technical Information of China (English)

    滑纬博; 李云凯; 吕燕

    2013-01-01

    在化工学习中,应用Aspen Plus对化工生产中的典型工艺——苯加氢合成环己烷系统进行模拟,结果表明,Aspen Plus不仅可以简化复杂的化工过程,而且可以提高学生学习的效率和质量,增强工程意识,有利于理论和实践的结合.

  18. Applications of Aspen Plus in the teaching of the separation engineering%Aspen Plus在《分离工程》教学中的应用

    Institute of Scientific and Technical Information of China (English)

    卢泽湘; 范立维; 廖益强

    2010-01-01

    分析了Aspen Plus化工流程模拟软件的学习方法,探讨了Aspen Plus软件在课程教学改革中的运用.教改结果表明,教学中软件的应用提高了学生的学习兴趣,加深了学生对课程内容的理解,同时拓宽了学生的视野,使课程教学更接近工程实际,获得了良好的教学效果.

  19. Aspen Plus Applied in Teaching of Chemical Engineering Design%Aspen plus在化工设计教学中应用

    Institute of Scientific and Technical Information of China (English)

    汪斌; 舒莉; 朱炳龙

    2010-01-01

    化工流程模拟软件Aspen plus在化工过程设计中得到了普遍应用,显著提高了化工工艺流程等方面的设计效率和水平.主要介绍该软件功能和应用方法,结合苯和甲苯精馏塔设计计算,讨论其在化工课程设计中的应用.将Aspen plus模拟值与文献值进行比较,相对误差小,符合较好.

  20. Multi-functional energy plantation; Multifunktionella bioenergiodlingar

    Energy Technology Data Exchange (ETDEWEB)

    Boerjesson, Paal [Lund Univ. (Sweden). Environmental and Energy Systems Studies; Berndes, Goeran; Fredriksson, Fredrik [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Physical Resource Theory; Kaaberger, Tomas [Ecotraffic, Goeteborg (Sweden)

    2002-02-01

    There exists a significant potential for utilising perennial energy plantations in protecting and restoring polluted water and land resources in Sweden. By optimising the design, location and management, several additional environmental services could be obtained which will increase the value of the energy plantations, thereby improving future market conditions for biomass. Multi-functional energy plantations (mainly Salix but also energy grass) can be divided into two categories, those designed for dedicated environmental services (e.g. vegetation filters for wastewater and sewage sludge treatment and shelter belts against soil erosion), and those generating more general benefits (e.g. soil carbon accumulation, increased soil fertility, cadmium removal and increased hunting potential). The practical potential of those two categories is estimated to be equivalent to up to 3% and more than 20% of the total Swedish arable land, respectively. The regional conditions of utilising multi-functional plantations vary, however, with the best possibilities in densely populated areas dominated by farmland. The economic value of multi-functional plantations is normally highest for those designed for dedicated environmental services. Purification of wastewater has the highest value, which could exceed the production cost in conventional Salix plantations, followed by treatment of polluted drainage water in vegetation filters and buffer zones (equivalent to more than half of the production cost), recirculation of sewage sludge (around half of the production cost), erosion control (around one fourth) and increased hunting potential (up to 15% of the production cost). The value of increased hunting potential varies due to nearness to larger cities and in which part of Sweden the plantation is located. The economic value of cadmium removal and increased soil fertility is equivalent to a few percent of the production cost, but the value of cadmium removal might increase in the

  1. [Effects of different type urban forest plantations on soil fertility].

    Science.gov (United States)

    Sun, Hui-zhen; Chen, Ming-yue; Cai, Chun-ju; Zhu, Ning

    2009-12-01

    Aimed to study the effects of different urban forest plantations on soil fertility, soil samples were collected from eight mono-cultured plantations (Larix gmelinii, Pinus sylvestris var. mongolica, Pinus tabulaeformis var. mukdensis, Phellodendron amurense, Juglans mandshurica, Fraxinus mandshurica, Betula platyphylla, and Quercus mongolica) and one mixed plantation (P. sylvestris var. mongolica + F. mandshurica + Picea koraiensis + P. amurense + B. platyphylla) established in Northeast Forestry University's Urban Forestry Demonstration Research Base in the 1950s, with two sites of neighboring farmland and abandoned farmland as the control. The soils in broadleaved forest plantations except Q. mongolica were near neutral, those in mixed plantation, L. gmelinii, P. sylvestris var. mongolica, and P. tabulaeformis var. mukdensis were slightly acidic, and that in Q. mongolica was acidic. The contents of soil organic matter, total N and P, available P and K, and hydrolysable N tended to decrease with soil depth. There existed significant differences in the chemical indices of the same soil layers among different plantations. The soil fertility was decreased in the order of F. mandshurica > P. amurense > mixed plantation > J. mandshurica > B. platyphylla > abandoned farmland > farmland > P. sylvestris var. mongolica > L. gmelinii > Q. mongolica > P. tabulaeformis var. mukdensis, suggesting that the soil fertility in broadleaved forest plantations except Q. mongolica and in mixed plantation increased, while that in needle-leaved forest plantations tended to decrease.

  2. Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade.

    Science.gov (United States)

    Kauffman, Matthew J; Brodie, Jedediah F; Jules, Erik S

    2010-09-01

    Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passive (sit-and-wait) predators have much stronger effects than active (coursing) predators. One BMTC that has been proposed for a wide-ranging active predator system involves the reintroduction of wolves (Canis lupus) to Yellowstone National Park, USA, which is thought to be leading to a recovery of trembling aspen (Populus tremuloides) by causing elk (Cervus elaphus) to avoid foraging in risky areas. Although this BMTC has been generally accepted and highly popularized, it has never been adequately tested. We assessed whether wolves influence aspen by obtaining detailed demographic data on aspen Stands using tree rings and by monitoring browsing levels in experimental elk exclosures arrayed across a gradient of predation risk for three years. Our study demonstrates that the historical failure of aspen to regenerate varied widely among stands (last recruitment year ranged from 1892 to 1956), and our data do not indicate an abrupt cessation of recruitment. This pattern of recruitment failure appears more consistent with a gradual increase in elk numbers rather than a rapid behavioral shift in elk foraging following wolf extirpation. In addition, our estimates of relative survivorship of young browsable aspen indicate that aspen are not currently recovering in Yellowstone, even in the presence of a large wolf population. Finally, in an experimental test of the BMTC hypothesis we found that the impacts of elk browsing on aspen demography are not diminished in sites where elk are at higher risk of predation by wolves. These findings suggest the need to further evaluate how trophic

  3. Aspen Plus 在化工热力学教学中的应用%Applications of Aspen Plus in the Teaching of Chemical Engineering Thermodynamics

    Institute of Scientific and Technical Information of China (English)

    丁雪; 刘熠斌; 宋春敏; 乔柯

    2014-01-01

    化工热力学是一门理论性强、逻辑性强、概念抽象、公式繁多的专业基础课。本文介绍了在化工热力学教学过程中引入Aspen Plus软件进行辅助教学,在优化教学内容、改善教学方法、提高学习效率、强化课程基础等方面进行有益的探索,认为引入Aspen Plus软件可以提高学生的学习兴趣,加深学生对课程内容的理解,提高学生的工程实践能力。%Chemical Engineering Thermodynamics was a professional basic course with strong theory , logicality , abstract concept and lots of formula.The citation of Aspen Plus to the teaching of chemical engineering thermodynamics was introduced.How to improve teaching content , teaching method , study efficiency and course base were investigated.When used Aspen Plus in the teaching of chemical engineering hemodynamics , the study interest , comprehension and engineering practice ability of students could be enhanced.

  4. The Application of Aspen Plus 7.3 in Chemical Engineering Design%Aspen Plus 7.3在化工设计中的应用

    Institute of Scientific and Technical Information of China (English)

    薛科创

    2014-01-01

    Chemical engineering design is the calculation process of the related parameters by computer. Because of the large amount of calculation, it must through the corresponding chemical simulation software to achieve. Aspen Plus 7.3 because the precise calculating, fast running speed, become the preferred software in chemical engineering design. This paper show the steps and methods of chemical engineering design by computer thought the flash condition is determined by Aspen Plus 7.3.%由于化工设计计算量大,必须通过相应的化工模拟软件来实现。Aspen Plus 7.3计算精确,运行速度快,成为化工设计者的首选软件。通过介绍利用Aspen Plus 7.3进行闪蒸条件的确定,说明利用计算机进行化工设计的步骤和方法。

  5. 基于Aspen Plus的褐煤热解过程模拟%The Lignite Coal Pyrolysis Process Simulation Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    王伟; 商玉坤; 武建军

    2011-01-01

    With high moisture lignite coal as an example, the method and procedure to build simplified model for coal pyrogenation process (CPD) using the chemical process simulation software Aspen Plus were introduced. Setting process of CPD model simulation parameter was given, and the Aspen Plus software was used to simulate the calculation process of coal pyrogenation, and the obtained simulation value was compared with the actual value. At the same time, the coal pyrolysis simulation process and the results were analyzed and provided basic reference to coal pyrogenation process development and optimization.%以高水分褐煤为例,介绍了利用Aspen Plus化工流程模拟软件建立煤热解过程简化模型的方法及步骤.阐述了CPD模型模拟参数的设置过程,并利用Aspen Plus软件对煤热解过程进行了模拟计算,将得出的模拟值与实际值进行了比较.同时,对煤热解模拟过程及结果进行了分析,给煤热解过程的工艺开发和工艺优化提供了参考依据.

  6. Dynamic Simulation of the Methanol Synthesis Reactor with the Aspen Dynamics Software%基于 Aspen Dynamics 的甲醇合成塔动态模拟

    Institute of Scientific and Technical Information of China (English)

    岳芳华; 刘东斌; 申延明

    2014-01-01

    以某年产300 kt甲醇合成装置为研究对象,利用先进的Aspen Plus工程设计软件对其进行全流程稳态模拟;并在稳态模拟的基础上,应用Aspen Dynamics软件对甲醇合成塔进行动态模拟,从而得到可供参考的最优的工艺控制参数,以指导实际生产操作。%Taking the 300 kt/a methanol synthesis unit as the study object ,make its whole process steady‐state simulation with the advanced Aspen Plus engineering design software . On the basis of steady‐state simulation ,make the dynamic simulation of methanol synthesis reactor with the Aspen Dynamics software to obtain the optimal control parameters for reference ,which could guide the actual production operations .

  7. The Challenges of Change. A Report from the Aspen Institute Seminar on Hispanic Americans and the Business Community (Aspen, Colorado, July 27-30, 1997).

    Science.gov (United States)

    McGuire, Georgianna; Nicolau, Siobhan

    This report from the 1997 Aspen Institute seminar concerns how demographic changes in American will affect Hispanic Americans' role in the business community. Section 1, "Lashes: Back, Front, and Sideways" (Harold Hodgkinson), describes pervasive national pessimism over demographic change and documents universal backlash to that change among all…

  8. Residential Access to Bandwidth: Exploring New Paradigms. A Report of the Annual Aspen Institute Conference on Telecommunications Policy (13th, August 9-13, 1998, Aspen, Colorado).

    Science.gov (United States)

    Entman, Robert M.

    The 1998 Aspen Systems Conference on Telecommunications Policy met to consider ways of speeding the deployment of telecommunication systems that allow for robust, reliable, and innovative communications services to the home. By organizing participants into three working groups, the session was able to come up with analytical suggestions and policy…

  9. Impact of epidermal leaf mining by the aspen leaf miner (Phyllocnistis populiella) on the growth, physiology, and leaf longevity of quaking aspen.

    Science.gov (United States)

    Wagner, Diane; DeFoliart, Linda; Doak, Patricia; Schneiderheinze, Jenny

    2008-08-01

    The aspen leaf miner, Phyllocnistis populiella, feeds on the contents of epidermal cells on both top (adaxial) and bottom (abaxial) surfaces of quaking aspen leaves, leaving the photosynthetic tissue of the mesophyll intact. This type of feeding is taxonomically restricted to a small subset of leaf mining insects but can cause widespread plant damage during outbreaks. We studied the effect of epidermal mining on aspen growth and physiology during an outbreak of P. populiella in the boreal forest of interior Alaska. Experimental reduction of leaf miner density across two sites and 3 years significantly increased annual aspen growth rates relative to naturally mined controls. Leaf mining damage was negatively related to leaf longevity. Leaves with heavy mining damage abscised 4 weeks earlier, on average, than leaves with minimal mining damage. Mining damage to the top and bottom surfaces of leaves had different effects on physiology. Mining on the top surface of the leaf had no significant effect on photosynthesis or conductance and was unrelated to leaf stable C isotope ratio (delta(13)C). Mining damage to the bottom leaf surface, where stomata are located, had significant negative effects on net photosynthesis and water vapor conductance. Percent bottom mining was positively related to leaf delta(13)C. Taken together, the data suggest that the primary mechanism for the reduction of photosynthesis by epidermal leaf mining by P. populiella is the failure of stomata to open normally on bottom-mined leaves.

  10. Plantation future of bamboo in China

    Institute of Scientific and Technical Information of China (English)

    LIZhao-hua; MikioKOBAYASHI

    2004-01-01

    In the past, utilization of bamboo resources in China has been traditionally dominated by direct consumption of local farmers as minor forest products with weak linkage with market. In recent years, the over-supply of grains and rapid degradation of agricultural environment call for alternative crops that can be developed through integrating the environmental plantation with the market demands. Closely associated with forestry and agriculture, bamboo is able to deal with the new challenges which China's agriculture is facing. Of 534 documented bamboo species in China, 153 species produce edibleshoots and of which 56 species are recommended for agricultural plantation; 139 species provide timbers and of which 58 species recommended; 116 species can be splited as good strips for weaving and of which 22 species recommended; 88 species are considered as garden bamboos and of which 34 species recommended; 45 species are able to produce paper pulp and of which 18 species recommended.

  11. Aspen Simulation of Diesel-Biodiesel Blends Combustion

    Directory of Open Access Journals (Sweden)

    Pérez-Sánchez Armando

    2015-01-01

    Full Text Available Biodiesel is a fuel produced by transesterification of vegetable oils or animal fats, which currently is gaining attention as a diesel substitute. It represents an opportunity to reduce CO2, SO2, CO, HC, PAH and PM emissions and contributes to the diversification of fuels in Mexico's energetic matrix. The results of the simulation of the combustion process are presented in this paper with reference to an engine specification KUBOTA D600-B, operated with diesel-biodiesel blends. The physicochemical properties of the compounds and the operating conditions of equipment were developed using the simulator Aspen® and supplementary information. The main aspects of the engine working conditions were considered such as diesel-biodiesel ratio, air/fuel mixture, temperature of the combustion gases and heat load. Diesel physicochemical specifications were taken from reports of PEMEX and SENER. Methyl esters corresponding to the transesterification of fatty acids that comprise castor oil were regarded as representative molecules of biodiesel obtained from chromatographic analysis. The results include CO2, water vapor, combustion efficiency, power and lower calorific value of fuels.

  12. Socio-Economic Importance Of Associated Plant Species In Short Rotation Coppice Plantations

    Directory of Open Access Journals (Sweden)

    Beniak Michal

    2015-05-01

    Full Text Available Many ecosystem services do not pass through markets. Therefore, the benefits which ecosystems provide to society are largely unrecorded. Fast-growing woody crops represent a quite new and still insufficiently explored ecosystem of agricultural land which has a potential to provide several utility functions. It may contribute to satisfaction of human needs and may enhance regional health. The goal of this paper was to detect the socio-economic importance of associated spontaneous vegetation in plantations of the energy crops (hybrids of the genera Salix and to compare it with the socio-economic importance of adjacent permanently cultivated agricultural field. There was examined the therapeutic, melliferous, feed, allergenic and toxic potential of undergrowth for each experimental plot inside the SRC plantations. The research was carried out on the agricultural land formerly used for growing cereals and root crops – the research base Kolíňany. Our results showed that energy plantation understoreys can be assumed to be the better option for contribution to the total socio-economic value of a region than agricultural fields.

  13. The Internet Time Lag: Anticipating the Long-Term Consequences of the Information Revolution. A Report of the Annual Aspen Institute Roundtable on Information Technology (10th, Aspen, Colorado, August 2-5, 2001).

    Science.gov (United States)

    Schwartz, Evan I.

    This is a report of the 10th annual Aspen Institute Roundtable on Information Technology (Aspen, Colorado, August 2-5, 2001). Participants were also polled after the events of September 11, and these comments have been integrated into the report. The mission of this report is to take a wide-ranging look at the trends that are defining the next new…

  14. Increasing the productivity of short-rotation Populus plantations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    DeBell, D.S.; Harrington, C.A.; Clendenen, G.W.; Radwan, M.A.; Zasada, J.C. [Forest Service, Olympia, WA (United States). Pacific Northwest Research Station

    1997-12-31

    This final report represents the culmination of eight years of biological research devoted to increasing the productivity of short rotation plantations of Populus trichocarpa and Populus hybrids in the Pacific Northwest. Studies provide an understanding of tree growth, stand development and biomass yield at various spacings, and how patterns differ by Populus clone in monoclonal and polyclonal plantings. Also included is some information about factors related to wind damage in Populus plantings, use of leaf size as a predictor of growth potential, and approaches for estimating tree and stand biomass and biomass growth. Seven research papers are included which provide detailed methods, results, and interpretations on these topics.

  15. Forest stand structure, productivity, and age mediate climatic effects on aspen decline

    Science.gov (United States)

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2014-01-01

    Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline.

  16. Differential response of aspen and birch trees to heat stress under elevated carbon dioxide.

    Science.gov (United States)

    Darbah, Joseph N T; Sharkey, Thomas D; Calfapietra, Carlo; Karnosky, David F

    2010-04-01

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO(2) and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO(2) protected photosynthesis of both species against moderate heat stress. Elevated CO(2) increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 degrees C) decreased all of these parameters in birch regardless of CO(2) treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO(2) were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO(2). Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms.

  17. Synergetic hydrothermal co-liquefaction of crude glycerol and aspen wood

    DEFF Research Database (Denmark)

    Pedersen, Thomas Helmer; Jasiunas, Lukas; Casamassima, Luca

    2015-01-01

    Crude glycerol-assisted hydrothermal co-liquefaction of aspen wood was studied in batch micro-reactors. An experimental matrix of 14 experiments was defined to investigate the effects of three different process parameters on the yields of biocrude and char, and on biocrude quality. Co-processing ......Crude glycerol-assisted hydrothermal co-liquefaction of aspen wood was studied in batch micro-reactors. An experimental matrix of 14 experiments was defined to investigate the effects of three different process parameters on the yields of biocrude and char, and on biocrude quality. Co......-processing aspen wood and neat glycerol led to a significant reduction in the char yield, and glycerol is hypothesized to act as a radical scavenger, alleviating re-polymerization of especially lignin-derived fragments. In the temperature range of 380–420 °C, it was found that biocrude and char yield, and biocrude...... quality were all invariant to the reaction temperature. By increasing the crude glycerol to aspen wood mass ratio from 0:1 to 3:1, char yield was decreased from 18.3% (only aspen wood) to 3.4%. Furthermore, the biocrude quality in terms of the effective hydrogen-to-carbon ratio (H/Ceff) was significantly...

  18. Phenology and climate relationships in aspen (Populus tremuloides Michx.) forest and woodland communities of southwestern Colorado

    Science.gov (United States)

    Meier, Gretchen A.; Brown, Jesslyn F.; Evelsizer, Ross J.; Vogelmann, James E.

    2014-01-01

    Trembling aspen (Populus tremuloides Michx.) occurs over wide geographical, latitudinal, elevational, and environmental gradients, making it a favorable candidate for a study of phenology and climate relationships. Aspen forests and woodlands provide numerous ecosystem services, such as high primary productivity and biodiversity, retention and storage of environmental variables (precipitation, temperature, snow–water equivalent) that affect the spring and fall phenology of the aspen woodland communities of southwestern Colorado. We assessed the land surface phenology of aspen woodlands using two phenology indices, start of season time (SOST) and end of season time (EOST), from the U.S. Geological Survey (USGS) database of conterminous U.S. phenological indicators over an 11-year time period (2001–2011). These indicators were developed with 250 m resolution remotely sensed data from the Moderate Resolution Imaging Spectroradiometer processed to highlight vegetation response. We compiled data on SOST, EOST, elevation, precipitation, air temperature, and snow water equivalent (SWE) for selected sites having more than 80% cover by aspen woodland communities. In the 11-year time frame of our study, EOST had significant positive correlation with minimum fall temperature and significant negative correlation with fall precipitation. SOST had a significant positive correlation with spring SWE and spring maximum temperature.

  19. Aspen Ecology in Rocky Mountain National Park: Age Distribution, Genetics, and the Effects of Elk Herbivory

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, Gerald A [ORNL; Yin, Tongming [ORNL

    2008-10-01

    Lack of aspen (Populus tremuloides) recruitment and canopy replacement of aspen stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado has been a cause of concern for more than 70 years (Packard, 1942; Olmsted, 1979; Stevens, 1980; Hess, 1993; R.J. Monello, T.L. Johnson, and R.G. Wright, Rocky Mountain National Park, 2006, written commun.). These aspen stands are a significant resource since they are located close to the park's road system and thus are highly visible to park visitors. Aspen communities are integral to the ecological structure of montane and subalpine landscapes because they contain high native species richness of plants, birds, and butterflies (Chong and others, 2001; Simonson and others, 2001; Chong and Stohlgren, 2007). These low-elevation, winter range stands also represent a unique component of the park's plant community diversity since most (more than 95 percent) of the park's aspen stands grow in coniferous forest, often on sheltered slopes and at higher elevations, while these winter range stands are situated on the low-elevation ecotone between the winter range grasslands and some of the park's drier coniferous forests.

  20. A simple PCR-based marker to determine sex in aspen.

    Science.gov (United States)

    Pakull, B; Kersten, B; Lüneburg, J; Fladung, M

    2015-01-01

    The genus Populus features a genetically controlled sex determination system, located on chromosome 19. However, different Populus species vary in the position of the sex-linked region on the respective chromosome and the apparent heterogametic sex, and the precise mechanism of sex determination in Populus is still unknown. Using next generation sequencing of pooled samples of male and female aspens, we identified the aspen homologue of the P. trichocarpa gene Potri.019G047300 ('TOZ19') to be male-specific. While in P. tremuloides, the complete gene is missing in the genome of female plants, a short fragment of the 3'-part of the gene is still present in P. tremula females. The male-specific presence and transcription of TOZ19 was further verified using PCR in various different aspen individuals and RT-PCR expression analysis. TOZ19 is potentially involved in early steps of flower development, and represents an interesting candidate gene for involvement in sex determination in aspen. Regardless of its role as candidate gene, TOZ19 represents an ideal marker for determination of the sex of non-flowering aspen individuals or seedlings.

  1. Perturbation of wood cellulose synthesis causes pleiotropic effects in transgenic aspen.

    Science.gov (United States)

    Joshi, Chandrashekhar P; Thammannagowda, Shivegowda; Fujino, Takeshi; Gou, Ji-Qing; Avci, Utku; Haigler, Candace H; McDonnell, Lisa M; Mansfield, Shawn D; Mengesha, Bemnet; Carpita, Nicholas C; Harris, Darby; Debolt, Seth; Peter, Gary F

    2011-03-01

    Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility, the overexpression of an aspen secondary wall-associated cellulose synthase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing, and weak branches adopted a weeping growth habit. Furthermore, transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

  2. Forest stand structure, productivity, and age mediate climatic effects on aspen decline.

    Science.gov (United States)

    Bell, David M; Bradford, John B; Lauenroth, William K

    2014-08-01

    Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline.

  3. Perturbation of Wood Cellulose Synthesis Causes Pleiotropic Effects in Transgenic Aspen

    Institute of Scientific and Technical Information of China (English)

    Chandrashekhar P.Joshi; Nicholas C.Carpita; Darby Harris; Seth DeBolt; Gary F.Peter; Shivegowda Thammannagowda; Takeshi Fujino; Ji-Qing Gou; Utku Avci; Candace H.Haigler; Lisa M.McDonnell; Shawn D.Mansfield; Bemnet Mengesha

    2011-01-01

    Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility,the overexpression of an aspen secondary wall-associated cellulose syn-thase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing,and weak branches adopted a weeping growth habit. Furthermore,transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

  4. Screening the Resilience of Short-Rotation Woody Crops to Climate Change

    Directory of Open Access Journals (Sweden)

    Sophan Chhin

    2016-01-01

    Full Text Available Sustainable woody biofeedstock production systems require a reliable supply of woody biomass that could be affected by future climate change. However, there is limited understanding of the climatic sensitivity of short rotation woody crops, such as hybrid aspens. The general objective of this study is to identify climatically resilient hybrid aspen clones for woody biomass feedstock development. Specifically, tree-ring analysis methods (dendrochronology were used to quantify the influence of climate on stem growth rates of hybrid aspens by measuring year-to-year changes in tree-ring width from different cultivars of hybrid aspen and relating annual growth patterns with past instrumental climate records (i.e., temperature and moisture index. Tree-ring analysis was conducted on a full-sib progeny plantation of different cultivars of hybrid aspens (Populus × smithii derived from different geographical variants of aspen parents: trembling aspen (Populus tremuloides and bigtooth aspen (Populus grandidentata located on Michigan State University property in the Sandhill Research Area (42.7°N latitude; 84.5°W longitude. Overall, the hybrid aspen families examined in this study were more sensitive to moisture related stressors compared to a weaker or no response to temperature stressors. By the end of the 21st century (2071–2100, 11 out of the 18 hybrid aspen families will be vulnerable to future changes in moisture stress, while the remaining families were screened to be resilient to future changes in moisture stress.

  5. 76 FR 15306 - Aspen Merchant Energy LP; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2011-03-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Aspen Merchant Energy LP; Supplemental Notice That Initial Market-Based Rate...-referenced proceeding of Aspen Merchant Energy LP's application for market-based rate authority, with...

  6. Optimization of Palm Oil Plantation Revitalization in North Sumatera Indonesia

    Directory of Open Access Journals (Sweden)

    Juliza Hidayati

    2015-01-01

    Full Text Available The idea of making North Sumatera  as a barometer of national oil palm industry require efforts commodities and agro-industry development of oil palm. One effort that can be done is by successful execution plantation revitalization. The plantation Revitalization is an effort to accelerate the development of smallholder plantations, through expansion and replanting by help of palm estate company as business partner and bank financed plantation revitalization fund. Business partner agreement obliged and bound to make at least the same smallholder plantation productivity with business partners, so that the refund rate to banks become larger and prosperous people as a plantation owner. Generally low productivity of smallholder plantations under normal potential caused a lot of old and damaged plants with plant material at random. The purpose of revitalizing oil palm plantations which are to increase their competitiveness through increased farm productivity. The research aims to identify potential criteria in influencing plantation productivity improvement priorities to be observed and followed up in order to improve the competitiveness of destinations and make North Sumatera barometer of national palm oil can be achieved. Research conducted with Analytical Network Process (ANP, to find the effect of dependency relationships between factors or criteria with the knowledge of the experts in order to produce an objective opinion and relevant depict the actual situation. 

  7. The role of plantation forestry in sustainable development

    Directory of Open Access Journals (Sweden)

    Ivetić Vladan

    2014-01-01

    Full Text Available The paper gives an overview of types of forest plantations and their role in sustainable development, with an emphasis on the definition of artificially established (planted forests and forest plantations. Forest plantations, the most productive part of planted forests, play a significant role in fulfilling the principles of sustainable development. Plantation forestry can provide additional quantities of roundwood and fuelwood (including biomass, additional products in the form of non-timber forest products and additional services in the form of shelterbelts and phytoremediation.

  8. Pathological Condition of Trees and Shrubs of Forest Plantations in the Middle and Lower Volga Region

    Directory of Open Access Journals (Sweden)

    Kolmukidi Svetlana Valeryevna

    2015-09-01

    Full Text Available The materials on the study of the characteristics of pathologies common in the protective forest plantations are presented. The basic factors of deterioration of woody species pathological conditions are identified. The most common and harmful diseases of the major tree species of the Lower and Middle Volga region are determined. The comparative tolerance of systematic structure of the main forest-forming species to diseases are revealed. The complex research of modern pathological condition of trees and shrubs agroforestry plantations in the steppe and dry steppe regions of Lower and Middle Volga is carried out. Arid climate and harsh growing conditions contribute to the weakening of the stability of trees and shrubs and the deterioration of the pathological state plantations. Abnormal weather conditions (high temperatures, insufficiency or lack of precipitation, strong winds, hot winds, careless use of fire were the reason of forest plantations death. The varying degrees of resistance to pathogens among systematic composition rocks of artificial planting: elm, poplar, birch, ash, maple and others are revealed. The diseases of various etiologies, aggressiveness and severity leading to partial or complete loss of epiphytotics are identified. The most harmful are the vascular pathology (Dutch elm disease, Verticillium of maple, necrotic and cancerous disease of poplar, rot, bacterial diseases. The Middle Volga region Submucusracemosa is the most immune to pathogens, but Ribesaureum is quite resistant to anthracnose and powdery mildew, meanwhile it is subject to Verticillium wilt (Fungi of the genus Verticillium. In the Lower Volga region Cotinuscoggygria and Loniceratatarica are resistant to pathogens. Ribesaureum is subject to anthracnose and Verticillium wilt, on the branches of shadberry necrosis sore meets. Leaves of pea tree suffer from Septoria and rust, branch necrosis and cancer. The use of more sustainable, fast-growing species, hybrids

  9. ASPEN PLUS在化工教学及科研中的应用

    Institute of Scientific and Technical Information of China (English)

    张毅博; 刘杨

    2015-01-01

    近年来,随着计算机技术的发展,大型的模拟仿真软件,尤其是Aspen Plus软件的应用,对推动化工专业教学及科研的发展起到了很大的作用。本文重点论述Aspen Plus软件在化工专业教学以及在科研中的应用。实践表明,Aspen Plus软件的使用,可以提高化工专业教学的质量,促进科研的的创新及发展。

  10. Aspen Plus”软件在化工生产中的应用

    Institute of Scientific and Technical Information of China (English)

    徐增花

    2013-01-01

      文章介绍了化工流程模拟软件“Aspen Plus”的主要功能及成功应用实例,应用实例表明,在化工生产中应用“Aspen Plus”软件不仅可以优化生产,而且还可以对某设备和整套生产装置的操作参数进行模拟分析,提高生产装置技术管理水平,从而产生巨大的经济效益,故应尽快在化工厂广大工程技术人员中推广使用“Aspen Plus”软件。

  11. Aspen Plus在化工专业教学中的应用

    Institute of Scientific and Technical Information of China (English)

    韩慧艳

    2013-01-01

    信息技术的普及推动了其在教育领域的应用,对提高教学质量起到了积极的促进作用。特别是Aspen Plus作为一种先进的计算机软件,凭借着较高的实验仿真能力,在化工专业教学中得到了广泛的应用。本文笔者在分析了化工专业课程体系的基础上,分析了Aspen Plus软件的优势,重点探讨了Aspen Plus在化工专业教学中的应用,目的是为化工专业教学提供指导和借鉴。

  12. Scale dependence of disease impacts on quaking aspen (Populus tremuloides) mortality in the southwestern United States

    Science.gov (United States)

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2015-01-01

    Depending on how disease impacts tree exposure to risk, both the prevalence of disease and disease effects on survival may contribute to patterns of mortality risk across a species' range. Disease may accelerate tree species' declines in response to global change factors, such as drought, biotic interactions, such as competition, or functional traits, such as allometry. To assess the role of disease in mediating mortality risk in quaking aspen (Populus tremuloides), we developed hierarchical Bayesian models for both disease prevalence in live aspen stems and the resulting survival rates of healthy and diseased aspen near the species' southern range limit using 5088 individual trees on 281 United States Forest Service Forest Inventory and Analysis plots in the southwestern United States.

  13. Improvement of bleached wheat straw pulp properties by using aspen high-yield pulp.

    Science.gov (United States)

    Zhang, Hongjie; Li, Jianguo; Hu, Huiren; He, Zhibin; Ni, Yonghao

    2012-09-01

    The bleached wheat straw pulp (BWSP) accounts for about 25% of the virgin fiber supply in the Chinese Pulp and Paper Industry. As a non-wood chemical pulp, BWSP is known to have low bulk, low light scattering coefficient and poor drainage due to its high content of parenchyma cells. In this study, a high-quality aspen high-yield pulp (HYP) was used to improve the BWSP properties at the laboratory scale. The results indicate that adding 5-20% aspen HYP into unrefined or refined BWSP can minimize many of the drawbacks associated with the BWSP: improving its drainage, bulk, light scattering coefficient and opacity. The addition of a small amount (up to 20%) of aspen HYP can also significantly increase the tear index of BWSP with only a slight decrease of the tensile index.

  14. Fibrillation of Aspen by Alkaline Cold Pre-treatment and Vibration Milling

    Directory of Open Access Journals (Sweden)

    Kärt KÄRNER

    2016-09-01

    Full Text Available In this article an attempt to fibrillate aspen bleached chemi-thermo mechanical pulp (BCTMP fibre in an environmentally friendly way is reported. The effects of various NaOH, KOH, urea and ethanol aqueous solutions at lowered temperature were tested for pre-treatment. The pre-treatment was followed by vibration milling aiming to peel off outer cell wall layers and to fibrillate S2 layer of the aspen wood fibre. The effects of the treatments were evaluated by scanning electron microscopy (SEM. The results show that it is possible to fibrillate BCTMP aspen fibres by using alkaline aqueous solutions at low temperatures followed by a mechanical treatment. A strong dependence on fibrillation of cellulose on temperature, time and alkali concentration was established.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7412

  15. Stand Dynamics, Humus Type and Water Balance Explain Aspen Long Term Productivity across Canada

    Directory of Open Access Journals (Sweden)

    Kenneth A. Anyomi

    2015-02-01

    Full Text Available This study examined the relative importance of soil, stand development and climate hypotheses in driving productivity for a species that is widely distributed in North America. Inventory plots, 3548 of such, either dominated by aspen or made up of species mixture of which aspen occurs in dominant canopy position were sampled along a longitudinal gradient from Quebec to British Columbia. Site index (SI, was used as a measure of productivity, and soil, climate and stand attributes were correlated with site index in order to determine their effects on productivity. Results show a decline in productivity with high moisture deficit. Soil humus correlates significantly with SI but does not sufficiently capture differential rates of litter deposition and decomposition effects over the long-term. Consequently, aspen composition, stand ageing, and stand structural changes dominate variability in productivity. Within the context where deciduous cover has being increasing, there are implications for forest productivity.

  16. Importance of crown architecture for leaf area index of different Populus genotypes in a high-density plantation.

    Science.gov (United States)

    Broeckx, L S; Verlinden, M S; Vangronsveld, J; Ceulemans, R

    2012-10-01

    Crown architecture is an important determinant of biomass production and yield of any bio-energy plantation since it determines leaf area display and hence light interception. Four Populus genotypes-of different species and hybrids and with contrasting productivity and leaf area-were examined in terms of their branch characteristics in relation to crown architecture during the first and second growing seasons after plantation establishment. The trees were planted at high density (8000 ha(-1)) on two different former land use types, cropland and pasture. We documented significant differences in branch architecture among the genotypes and for the first year among the former land use types. Land use effects only affected factors not related to canopy closure and wood production, and decreased after the first growing season. This suggested that both former land use types were equally suited for the establishment success of a poplar bio-energy plantation. Tree height and branch dimensions-branch diameter and branch length-were the most important determinants of wood production and maximum leaf area index. Despite the secondary importance of the number of sylleptic branches, these branches contributed significantly to the total leaf area in three out of the four studied genotypes. This indicated that enhanced syllepsis accelerates leaf area development and hence carbon assimilation, especially in the early stages of a high-density plantation with poplar.

  17. Defensive effects of extrafloral nectaries in quaking aspen differ with scale.

    Science.gov (United States)

    Mortensen, Brent; Wagner, Diane; Doak, Patricia

    2011-04-01

    The effects of plant defenses on herbivory can differ among spatial scales. This may be particularly common with indirect defenses, such as extrafloral nectaries (EFNs), that attract predatory arthropods and are dependent on predator distribution, abundance, and behavior. We tested the defensive effects of EFNs in quaking aspen (Populus tremuloides Michx.) against damage by a specialist herbivore, the aspen leaf miner (Phyllocnistis populiella Cham.), at the scale of individual leaves and entire ramets (i.e., stems). Experiments excluding crawling arthropods revealed that the effects of aspen EFNs differed at the leaf and ramet scales. Crawling predators caused similar reductions in the percent leaf area mined on individual leaves with and without EFNs. However, the extent to which crawling predators increased leaf miner mortality and, consequently, reduced mining damage increased with EFN expression at the ramet scale. Thus, aspen EFNs provided a diffuse defense, reducing damage to leaves across a ramet regardless of leaf-scale EFN expression. We detected lower leaf miner damage and survival unassociated with crawling predators on EFN-bearing leaves, suggesting that direct defenses (e.g., chemical defenses) were stronger on leaves with than without EFNs. Greater direct defenses on EFN-bearing leaves may reduce the probability of losing these leaves and thus weakening ramet-scale EFN defense. Aspen growth was not related to EFN expression or the presence of crawling predators over the course of a single season. Different effects of aspen EFNs at the leaf and ramet scales suggest that future studies may benefit from examining indirect defenses simultaneously at multiple scales.

  18. Net primary production and its change in Chinese plantation

    Science.gov (United States)

    Jun, Shi; Gao, Zhiqiang; Linli, Cui

    2006-08-01

    NPP is not only the original driver of carbon cycle, but also has significance in global change research. In this study, NPP data from GLO-PEM model and Chinese plantation data were used to explore the spatial and temporal changes of NPP in Chinese plantation area from 1981 to 2000. As the results, mean annual NPP in Chinese plantation area was about 663.37gCm -2yr -1 in the past 20 years, with higher NPP in several provinces in South China, and lower NPP in some arid and semi-arid regions in Northeast China, North China and Northwest China. NPP increased more in the eastern part of North China and in Central China and South China, but decreased in most regions of West China, North Liaoning, East Jilin and North Heilongjiang. Monthly variation of plantation NPP was mainly in phase from June to September, especially in July and August during the 4 th times from 1996 to 2000, monthly NPP increased most. Mixed plantation had the highest mean annual NPP and coniferous plantation had the least. Plantation in East China had higher mean annual NPP, annual NPP increase rate and monthly NPP variation than that in West China. The increment of total annual NPP in Chinese plantation from 1980's to 1990's was 84.51×10 4tCyr -1. Plantation in Hainan province had the highest mean annual NPP and NPP increase, and plantation in Guangdong province had the largest total annual NPP increase in the past 20 years, but in Xinjiang province, mean annual NPP in plantation area was lowest and decreasing.

  19. Aspen Plus在泵选型设计中的应用

    Institute of Scientific and Technical Information of China (English)

    黄卫国

    2007-01-01

    应用Aspen Plus软件进行泵选型,先计算管线压降,初步确定泵的扬程和型号;然后输入泵的性能曲线,整个输送系统联合模拟,核算泵的性能。由于Aspen Plus软件拥有强大的物性数据库,所以输入简便,计算结果准确,可显著提高设计效率。

  20. Landscape dynamics in aspen and western juniper woodlands on the Owyhee Plateau, Idaho

    Science.gov (United States)

    Strand, Eva K.

    A century of altered fire regimes has affected the landscape vegetation dynamics in the Intermountain West. Suppression of wildfires has resulted in increases in woody plant cover in these semi-arid ecosystems, which has resulted in land cover changes affecting biogeochemical cycling, landscape composition, and habitat diversity. Recent developments in remote sensing technology, computational power, and a rapid development of analysis techniques have enabled us to quantify such changes at the landscape scale. Wavelet analysis is a powerful image analysis technique that is here applied in a novel fashion to fine scale remote sensing imagery to automatically detect the location and crown diameter of individual western juniper plants (Juniperus occidentalis ssp. occidentalis) expanding into sagebrush (Artemisia spp.) steppe at multiple scales. The produced marked point pattern of historical and current spatial juniper distribution was compared regionally and changes in foliar cover and above ground biomass were estimated across a 330,000 ha area on the Owyhee Plateau, Idaho. The above ground carbon accumulation rate from 1946 to 1998 was estimate to be 3.3 gCm-2yr-1 and 10.0 gCm-2yr -1 employing the wavelet and conventional texture analysis methods, respectively, with an additional 25% rise in belowground carbon accumulation in root stock. This research further demonstrates that estimates of carbon accumulation rates as a result of woody encroachment are highly dependent on the spatial and temporal scales of analysis. Conifer species, western juniper and Douglas-fir (Pseudotsuga menziesii) on the Owyhee Plateau, have further expanded into the biologically important quaking aspen ( Populus tremuloides) habitats resulting in conifer dominance and occasional loss of aspen clones. Classification of remotely sensed imagery combined with spatially explicit modeling of aspen successional stages indicate that, in the absence of management activity, loss of seral aspen stands

  1. Analysis of aspen-and-birch separated small woods’ vegetation in North Steppe of Ukraine

    Directory of Open Access Journals (Sweden)

    N. M. Nazarenko

    2010-09-01

    Full Text Available Conducted analysis of forest vegetation has allowed selecting and specifying classification and typological units of the aspen-and-birch separated small woods, which have statistically significant difference of ecotopic and coenotic parameters. Those parameters of studied forest ecosystems are characterised. Existence of the lines of hygrogenic and edaphogenic substitution, and succession rows are described. Phytoindication description of ecological factors’ pivotal conditions is presented. Driving factors determining parameters, structure and composition of the aspen-and-birch forest ecosystems are diminishing soil moisture, increasing annual temperatures amplitude and soil acidity.

  2. Aspen Plus软件在气体分馏装置中的应用%Application of Aspen Plus in Gas Fractionation Plant

    Institute of Scientific and Technical Information of China (English)

    孙献菊

    2006-01-01

    介绍了Aspen Plus软件在齐鲁分公司胜利炼油厂气分装置上的应用情况,主要包括:利用Aspen Plus软件准确模拟了气分装置的生产工况,优化了脱丙烷塔的操作条件,并在实际中得到了应用.分析了原料变化后装置操作工艺条件的变化情况,为生产工艺方案的制定提供了很好的指导,缩短了装置的调整时间.

  3. Study of Coal Gasification System Based on ASPEN PLUS Platform%基于ASPEN PLUS平台煤气化系统研究

    Institute of Scientific and Technical Information of China (English)

    范峻铭; 诸林

    2014-01-01

    传统燃煤利用方式不仅造成煤热能利用效率低下,也使环境受到极大的破坏.煤气化是实现煤清洁和合理化利用的关键技术.目前多利用ASPEN PLUS软件模拟煤气化过程,并在该领域得到了越来越多的应用.因此,重点分析利用ASPEN PLUS建立煤气化模型的方法和原理,以期为今后研究提供方法性指导.

  4. OPTIMIZATION OF METHANOL/WATER SPLITTER WITH ASPEN PLUS%用AspenPlus优化甲醇水分离塔操作

    Institute of Scientific and Technical Information of China (English)

    姬加良

    2011-01-01

    To simulate the methanol/water splitter in Rectisol Plant with Aspen Plus engineering soft-ware for comparison with PDP;to optimize the working condition for the top methanol reflux under different water content and to compare the optimized data with the%应用AspenPlus工程软件对低温甲醇洗装置的甲醇水分离塔进行模拟,并与设计工艺包进行对比。对塔顶回流甲醇在不同含水量下的工况进行优化,将优化数据与该塔实际运行结果进行比较,为生产操作提供数据指导。

  5. Yield of a Choctawhatchee Sand Pine Plantation at Age 28

    Science.gov (United States)

    Russell M. Burns; R.H. Brendemuehl

    1969-01-01

    A little-known tree, Choctawhatchee sand pine (Pinus clausa [Chapm.] Vasey), seems well adapted to the infertile, droughty soils common to the sandhills of Florida which now produce little value. Published yield data based on plantation-grown Choctawhatchee sand pine are not available. One 28-year-old plantation of this race of sand pine, growing...

  6. Green gold : on variations of truth in plantation forestry

    NARCIS (Netherlands)

    Romeijn, P.

    1999-01-01

    The "variations of truth in plantation forestry" is a study on the Teakwood investment program. Teakwood offered the general public in The Netherlands the opportunity to directly invest in a teak plantation in Costa Rica. The program was pioneered in 1989 and truly gained momentum when it

  7. Green Gold. On variations of truth in plantation forestry

    NARCIS (Netherlands)

    Romeijn, P.

    1999-01-01

    The "variations of truth in plantation forestry" is a study on the Teakwood investment program. Teakwood offered the general public in The Netherlands the opportunity to directly invest in a teak plantation in Costa Rica. The program was pioneered in 1989 and truly gained momentum when it was joined

  8. Does forest certification enhance community engagement in Australian plantation management?

    NARCIS (Netherlands)

    Dare, Melanie (Lain); Vanclay, Frank; Schirmer, Jacki

    2011-01-01

    The rapid expansion of timber plantations across Australia has been contentious, with ongoing debate in rural communities about the social, economic and environmental impacts of plantations. The need for effective and ongoing community engagement (CE) has been highlighted by this ongoing contention

  9. High tonnage harvesting and skidding for loblolly pine energy plantations

    Science.gov (United States)

    Patrick Jernigan; Tom Gallagher; Dana Mitchell; Mathew Smidt; Larry Teeter

    2016-01-01

    The southeastern United States has a promising source for renewable energy in the form of woody biomass. To meet the energy needs, energy plantations will likely be utilized. These plantations will contain a high density of small-stem pine trees. Since the stems are relatively small when compared with traditional product removal, the harvesting costs will increase. The...

  10. Yield model for unthinned Sitka spruce plantations in Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Omiyale, O.; Joyce, P.M.

    1982-01-01

    Over the past few decades the construction of yield models, has progressed from the graphical through mathematical and biomathematic approach. The development of a biomathematical growth model for Sitka spruce plantations is described. It is suggested that this technique can serve as a basis for general yield model construction of plantation species in Ireland. (Refs. 15).

  11. Yaughan and Curriboo Plantations: Studies in Afro-American Archaeology.

    Science.gov (United States)

    1983-04-01

    Wheaton, Thomas R., Jr. 1976 La ceramica clasica del area de Huejotzingo, Puebla . Comunicaciones. 13:25-32. 1980 Architecture at Curriboo and Yaughan...Thurston retained part of the old Yaughan Plantation; in 1863 , a sale of land contained in Currlboo plantation positioned the parcel on "Lands of the

  12. The Application of Aspen One v7 in Chemical Separation Engineering Teaching%Aspen one v7在分离工程教学中的应用

    Institute of Scientific and Technical Information of China (English)

    路华清

    2010-01-01

    分离工程是化工类专业重要专业课,是一门实践性非常强的课程.各种平衡分离过程的计算既是教学的重点,又是教学的难点.随着电脑在学生中普及率的提高,为使用模拟软件进行辅助教学提供了条件.使用aspen one v7的aspen properties模块和aspen plu.模块辅助教学,学生在aspen properties中完成物性参数计算、逸度系数、活度系数、平衡常数计算、泡露点计算等分离工程基础数据计算,同时熟悉aspen one软件的使用,为后续在aspen plus中完成单级平衡分离计算、精馏吸收严格计算打下基础.同时,在分离工程教学过程中引入aspen one的应用,为后续课程"化工过程模拟"的教学打下基础,收到较好的教学效果.

  13. Aspen Tension Wood Fibers Contain β-(1---> 4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in Gelatinous Walls.

    Science.gov (United States)

    Gorshkova, Tatyana; Mokshina, Natalia; Chernova, Tatyana; Ibragimova, Nadezhda; Salnikov, Vadim; Mikshina, Polina; Tryfona, Theodora; Banasiak, Alicja; Immerzeel, Peter; Dupree, Paul; Mellerowicz, Ewa J

    2015-11-01

    Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula × Populus tremuloides). β-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. β-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, β-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high β-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.

  14. Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves.

    Science.gov (United States)

    Niinemets, Ülo; Sun, Zhihong; Talts, Eero

    2015-12-01

    Leaf age alters the balance between the use of end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP), in prenyltransferase reactions leading to synthesis of pigments of photosynthetic machinery and in isoprene synthesis, but the implications of such changes on environmental responses of isoprene emission have not been studied. Because under light-limited conditions, isoprene emission rate is controlled by DMADP pool size (SDMADP ), shifts in the share of different processes are expected to particularly strongly alter the light dependency of isoprene emission. We examined light responses of isoprene emission in young fully expanded, mature and old non-senescent leaves of hybrid aspen (Populus tremula x P. tremuloides) and estimated in vivo SDMADP and isoprene synthase activity from post-illumination isoprene release. Isoprene emission capacity was 1.5-fold larger in mature than in young and old leaves. The initial quantum yield of isoprene emission (αI ) increased by 2.5-fold with increasing leaf age primarily as the result of increasing SDMADP . The saturating light intensity (QI90 ) decreased by 2.3-fold with increasing leaf age, and this mainly reflected limited light-dependent increase of SDMADP possibly due to feedback inhibition by DMADP. These major age-dependent changes in the shape of the light response need consideration in modelling canopy isoprene emission.

  15. Aspen Flare-net在火炬管网设计中的应用%Application of Aspen Flare-net in Design of Flare-net

    Institute of Scientific and Technical Information of China (English)

    匡顺强; 张斌

    2015-01-01

    介绍了Aspen Flare-net软件在火炬管网设计分析中的计算原理和计算步骤,并简要介绍了软件的主要特性、主要功能以及软件的计算选项。通过对一改扩建项目中新增的低压火炬排放气排放至原低压火炬系统进行火炬管网压力降核算分析,核算结果表明,原低压火炬系统无需改造,即可满足改扩建后新增低压火炬排放气的安全排放要求。同时表明Aspen Flare-net软件在火炬管网工程设计中的应用价值。%In this article, the calculating principles and procedures of software Aspen Flare-net were, including its maln characteristics, maln functions and application choices, introduced in the design and analysis of flare-net. With the analysis of pressure drop in lfare-net due to the discharge of gas from newly added low pressure lfare to the original low pressure lfare-net in one expanded project, it was concluded that it is unnecessary to reform the originated lfare-net that the safe discharge requirements for newly added low pressure lfare can be met. At the same times, it was shown that software Aspen Flare-net is quite useful in the design of lfare-net.

  16. Development & Application of Aspen Orion System in Refinery%炼油企业Aspen Orion系统开发与应用

    Institute of Scientific and Technical Information of China (English)

    王军

    2004-01-01

    随着全球经济的一体化,企业之间的竞争加剧.为降低成本、提高资源利用率,炼油企业都在积极运用优化技术和计算机技术追求利益的最大化.简要介绍了Aspen Orion系统及其在炼油厂的实际应用.

  17. Simulation of Rectified Reaction Process-Example of Using ASPEN PLUS%反应精馏过程模拟——ASPEN PLUS应用范例

    Institute of Scientific and Technical Information of China (English)

    杨绪壮; 屈一新

    2001-01-01

    本文利用ASPEN PLUS软件对环氧丙烷水解生成丙二醇的反应精馏过程进行模拟计算,对有关物系的相行为进行预测,并进行物性计算和流程模拟,指明了该反应过程的主反应区及其形成原因.

  18. 物性估算在ASPEN PLUS软件中的应用%Application of Properties Estimation in ASPEN PLUS Software

    Institute of Scientific and Technical Information of China (English)

    戚一文; 方云进

    2007-01-01

    利用Aspen Plus软件提供的物性估算功能,计算发酵液中低浓度1,3-丙二醇分离的中间产物2-甲基-1,3-二哑烷(2MD)的物性,从而模拟分离过程,确定工艺条件,得到理想的产物结果.

  19. Application of ASPEN PLUS in Methanol Distillation Column in MDI Plant%ASPEN PLUS在MDI装置的甲醇除去塔中的应用

    Institute of Scientific and Technical Information of China (English)

    徐宝学

    2008-01-01

    基于作者多年的工程技术开发经验介绍了ASPEN PLUS软件在MDI(二苯基甲烷二异氰酸酯)装置的甲醇除去塔设计中的应用,模拟与设计结果成功用于公司的16万t/a MDI的建设.

  20. Aspen Plus模拟汽油分馏塔系统%Simulation of gasoline fractionator system by Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    堵祖荫

    2002-01-01

    Aspen Plus模拟乙烯装置汽油分馏塔系统,其轻烃部分物性可以用Peng-Robison、Redich-Kwong-Seave等状态方程来描述,馏分油部分物性则用虚拟组分(Fictitious Components)描述,文章还以此研究了各工艺参数对塔板温度的影响.

  1. Aspen Plus在煤焦油复杂组分精馏中的应用%Application of Aspen Plus in the Complex Components Distillation

    Institute of Scientific and Technical Information of China (English)

    杨云; 许祥军

    2009-01-01

    在制备净化煤焦油沥青的过程中,净化沥青和轻质油组分的精馏分离是关键步骤之一.通过对组分的合理简化,用Aspen Plus对这一复杂组分精馏过程进行模拟,为试验及设计提供参考.

  2. ASPEN PLUS 对混合二甲苯分离工艺的分析研究%Research on Separation of mixed Xylene Using ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    刘春法; 孙剑; 阮栋

    2005-01-01

    C8芳烃(混合二甲苯)由于组分来源的不同,组分较多,组分间沸点差很小,使C8芳烃分离可供选择的流程很多.化工分公司应用ASPEN PLUS软件,研究了超精馏工艺分离混合二甲苯的可行性.

  3. 乳化炸药水相的ASPEN PLUS物性分析%Emulsion Explosives' Water-phase Material ASPEN PLUS Analysis

    Institute of Scientific and Technical Information of China (English)

    曾开亮

    2013-01-01

    文章结合乳化炸药传统水相材料物性实际数据,用ASPEN PLUS软件对使用硝铵水溶液的水相材料在不同温度下进行了pure和binary物性分析,物性分析方法为PENG-ROB法和RK-SOAVE法,分析结果与实际数据相符合.

  4. APPLICATION OF ASPEN PLUS PROCESS SIMULATION SOFTWARE IN LLDPE PLANT%Aspen Plus流程模拟软件在LLDPE装置上的应用

    Institute of Scientific and Technical Information of China (English)

    高彤; 赵熠

    2008-01-01

    以LLDPE装置全流程模拟为例,对应用Aspen Plus软件进行分析和讨论.通过相关理论计算开发出了LLDPE装置流程模拟模型,并成功运用于实际生产,为安全稳定的进行牌号切换和开发新产品提供了依据.

  5. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment.

    Science.gov (United States)

    Uddling, Johan; Hogg, Alan J; Teclaw, Ronald M; Carroll, Mary Anne; Ellsworth, David S

    2010-06-01

    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated concentrations of CO2 and O3, alone and in combination, affected the accumulated stomatal flux of O3 (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O3 was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O3 deposition. Leaf-level AFst (AFst(l)) was not reduced by elevated CO2. Instead, there was a significant CO2 x O(3) interaction on AFst(l), as a consequence of lower values of gs in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst(l) than birch leaves, and estimates of AFst(l) were not very sensitive to non-stomatal leaf surface O3 deposition. Our results suggest that model projections of large CO2-induced reductions in gs alleviating the adverse effect of rising tropospheric O3 may not be reasonable for northern hardwood forests.

  6. Wood Quality of Acacia Hybrid and Second-Generation Acacia mangium

    OpenAIRE

    Ismail Jusoh; Farawahida Abu Zaharin; Nur Syazni Adam

    2013-01-01

    Two new tree variants, namely Acacia hybrid and second-generation Acacia mangium, have been introduced in plantation forests in Sarawak, Malaysia, and their wood qualities were examined. The mean basic density of Acacia hybrid was comparable with Acacia mangium. However basic density and strength properties of second-generation A. mangium were significantly lower compared to Acacia hybrid. The mean fibre length and fibre wall thickness in the hybrid were found to be greater than that of secon...

  7. Conifer expansion reduces the competitive ability and herbivore defense of aspen by modifying light environment and soil chemistry.

    Science.gov (United States)

    Calder, W John; Horn, Kevin J; St Clair, Samuel B

    2011-06-01

    Disturbance patterns strongly influence plant community structure. What remains less clear, particularly at a mechanistic level, is how changes in disturbance cycles alter successional outcomes in plant communities. There is evidence that fire suppression is resulting in longer fire return intervals in subalpine forests and that these lengthened intervals increase competitive interactions between aspen and conifer species. We conducted a field and greenhouse study to compare photosynthesis, growth and defense responses of quaking aspen and subalpine fir regeneration under light reductions and shifts in soil chemistry that occur as conifers increase in dominance. The studies demonstrated that aspen regeneration was substantially more sensitive to light and soil resource limitations than that of subalpine fir. For aspen, light reductions and/or shifts in soil chemistry limited height growth, biomass gain, photosynthesis and the production of defense compounds (phenolic glycosides and condensed tannins). Biomass gain and phenolic glycoside concentrations were co-limited by light reduction and changes in soil chemistry. In contrast, subalpine fir seedlings tended to be more tolerant of low light conditions and showed no sensitivity to changes in soil chemistry. Unlike aspen, subalpine fir increased its root to shoot ratio on conifer soils, which may partially explain its maintenance of growth and defense. The results suggest that increasing dominance of conifers in subalpine forests alters light conditions and soil chemistry in a way that places greater physiological and growth constraints on aspen than subalpine fir, with a likely outcome being more successful recruitment of conifers and losses in aspen cover.

  8. Disentangling herbivore impacts on Populus tremuloides: a comparison of native ungulates and cattle in Canada's Aspen Parkland.

    Science.gov (United States)

    Bork, Edward W; Carlyle, Cameron N; Cahill, James F; Haddow, Rae E; Hudson, Robert J

    2013-11-01

    Ungulates impact woody species' growth and abundance but little is understood about the comparative impacts of different ungulate species on forest expansion in savanna environments. Replacement of native herbivore guilds with livestock [i.e., beef cattle (Bos taurus)] has been hypothesized as a factor facilitating trembling aspen (Populus tremuloides Michx.) encroachment into grasslands of the Northern Great Plains. We used a controlled herbivory study in the Parklands of western Canada to compare the impact of native ungulates and cattle on aspen saplings. Native ungulate treatments included a mixed species guild and sequences of herbivory by different ungulates [bison (Bison bison subsp. bison), elk (Cervus elaphus) then deer (Odocoileus hemionus); or deer, elk, then bison]. Herbivory treatments were replicated in three pastures, within which sets of 40 marked aspen saplings (aspen stand. Stems were assessed for mortality and incremental damage (herbivory, leader breakage, stem abrasion and trampling). Final mortality was greater with exposure to any type of herbivore, but remained similar between ungulate treatments. However, among all treatments, the growth of aspen was highest with exposure only to cattle. Herbivory of aspen was attributed primarily to elk within the native ungulate treatments, with other forms of physical damage, and ultimately sapling mortality, associated with exposure to bison. Overall, these results indicate that native ungulates, specifically elk and bison, have more negative impacts on aspen saplings and provide evidence that native and domestic ungulates can have different functional effects on woody plant dynamics in savanna ecosystems.

  9. Using Aspen to Teach Chromatographic Bioprocessing: A Case Study in Weak Partitioning Chromatography for Biotechnology Applications

    Science.gov (United States)

    Evans, Steven T.; Huang, Xinqun; Cramer, Steven M.

    2010-01-01

    The commercial simulator Aspen Chromatography was employed to study and optimize an important new industrial separation process, weak partitioning chromatography. This case study on antibody purification was implemented in a chromatographic separations course. Parametric simulations were performed to investigate the effect of operating parameters…

  10. Using Aspen to Teach Chromatographic Bioprocessing: A Case Study in Weak Partitioning Chromatography for Biotechnology Applications

    Science.gov (United States)

    Evans, Steven T.; Huang, Xinqun; Cramer, Steven M.

    2010-01-01

    The commercial simulator Aspen Chromatography was employed to study and optimize an important new industrial separation process, weak partitioning chromatography. This case study on antibody purification was implemented in a chromatographic separations course. Parametric simulations were performed to investigate the effect of operating parameters…

  11. Increased saccharification yields from aspen biomass upon treatment with enzymatically generated peracetic acid.

    Science.gov (United States)

    Duncan, Shona; Jing, Qing; Katona, Adrian; Kazlauskas, Romas J; Schilling, Jonathan; Tschirner, Ulrike; Aldajani, Waleed Wafa

    2010-03-01

    The recalcitrance of lignocellulosic biomass to enzymatic release of sugars (saccharification) currently limits its use as feedstock for biofuels. Enzymatic hydrolysis of untreated aspen wood releases only 21.8% of the available sugars due primarily to the lignin barrier. Nature uses oxidative enzymes to selectively degrade lignin in lignocellulosic biomass, but thus far, natural enzymes have been too slow for industrial use. In this study, oxidative pretreatment with commercial peracetic acid (470 mM) removed 40% of the lignin (from 19.9 to 12.0 wt.% lignin) from aspen and enhanced the sugar yields in subsequent enzymatic hydrolysis to about 90%. Increasing the amount of lignin removed correlated with increasing yields of sugar release. Unfortunately, peracetic acid is expensive, and concentrated forms can be hazardous. To reduce costs and hazards associated with using commercial peracetic acid, we used a hydrolase to catalyze the perhydrolysis of ethyl acetate generating 60-70 mM peracetic acid in situ as a pretreatment to remove lignin from aspen wood. A single pretreatment was insufficient, but multiple cycles (up to eight) removed up to 61.7% of the lignin enabling release of >90% of the sugars during saccharification. This value corresponds to a predicted 581 g of fermentable sugars from 1 kg of aspen wood. Improvements in the enzyme stability are needed before the enzymatically generated peracetic acid is a commercially viable alternative.

  12. Root carbon reserve dynamics in aspen seedlings: does simulated drought induce reserve limitation?

    Science.gov (United States)

    Galvez, David A; Landhäusser, S M; Tyree, M T

    2011-03-01

    In a greenhouse study we quantified the gradual change of gas exchange, water relations and root reserves of aspen (Populus tremuloides Michx.) seedlings growing over a 3-month period of severe water stress. The aim of the study was to quantify the complex interrelationship between growth, water and gas exchange, and root carbon (C) dynamics. Various growth, gas exchange and water relations variables in combination with root reserves were measured periodically on seedlings that had been exposed to a continuous drought treatment over a 12-week period and compared with well-watered seedlings. Although gas exchange and water relations parameters significantly decreased over the drought period in aspen seedlings, root reserves did not mirror this trend. During the course of the experiment roots of aspen seedlings growing under severe water stress showed a two orders of magnitude increase in sugar and starch content, and roots of these seedlings contained more starch relative to sugar than those in non-droughted seedlings. Drought resulted in a switch from growth to root reserves storage which indicates a close interrelationship between growth and physiological variables and the accumulation of root carbohydrate reserves. Although a severe 3-month drought period created physiological symptoms of C limitation, there was no indication of a depletion of root C reserve in aspen seedlings.

  13. Final Harvest of Above-Ground Biomass and Allometric Analysis of the Aspen FACE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mark E. Kubiske

    2013-04-15

    The Aspen FACE experiment, located at the US Forest Service Harshaw Research Facility in Oneida County, Wisconsin, exposes the intact canopies of model trembling aspen forests to increased concentrations of atmospheric CO2 and O3. The first full year of treatments was 1998 and final year of elevated CO2 and O3 treatments is scheduled for 2009. This proposal is to conduct an intensive, analytical harvest of the above-ground parts of 24 trees from each of the 12, 30 m diameter treatment plots (total of 288 trees) during June, July & August 2009. This above-ground harvest will be carefully coordinated with the below-ground harvest proposed by D.F. Karnosky et al. (2008 proposal to DOE). We propose to dissect harvested trees according to annual height growth increment and organ (main stem, branch orders, and leaves) for calculation of above-ground biomass production and allometric comparisons among aspen clones, species, and treatments. Additionally, we will collect fine root samples for DNA fingerprinting to quantify biomass production of individual aspen clones. This work will produce a thorough characterization of above-ground tree and stand growth and allocation above ground, and, in conjunction with the below ground harvest, total tree and stand biomass production, allocation, and allometry.

  14. Risk Communication, Metacommunication, and Rhetorical Stases in the Aspen-EPA Superfund Controversy.

    Science.gov (United States)

    Stratman, James F.; And Others

    1995-01-01

    Explores the relationship between current theoretical definitions of risk communication, the unique national role that EPA plays in defining health and environmental risks, and possible explanations for EPA's inability to persuade Aspen, Colorado, to accept a cleanup plan. Explores ownership messages conveyed through metacommunication conflict…

  15. AspenTech to Provide VPS for CNOOC-Shell Nanhai Petrochemicals Complex

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ AspenTech, a US supplier of software and services to the process industries, recently announced it has been awarded a contract to supply a series of operator training simulators for the US$4.3 billion Nanhai Petrochemicals Project of CNOOC-Shell Petrochemical Company (CSPC)at Daya Bay in Huizhou City in South China's Guangdong Province.

  16. Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales.

    Science.gov (United States)

    Madritch, Michael D; Kingdon, Clayton C; Singh, Aditya; Mock, Karen E; Lindroth, Richard L; Townsend, Philip A

    2014-01-01

    Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America. We combine imaging spectroscopy (AVIRIS) data with genetic, phytochemical, microbial and biogeochemical data to determine how intraspecific plant genetic variation influences below-ground processes at landscape scales. We demonstrate that both canopy chemistry and below-ground processes vary over large spatial scales (continental) according to aspen genotype. Imaging spectrometer data distinguish aspen genotypes through variation in canopy spectral signature. In addition, foliar spectral variation correlates well with variation in canopy chemistry, especially condensed tannins. Variation in aspen canopy chemistry, in turn, is correlated with variation in below-ground processes. Variation in spectra also correlates well with variation in soil traits. These findings indicate that forest tree species can create spatial mosaics of ecosystem functioning across large spatial scales and that these patterns can be quantified via remote sensing techniques. Moreover, they demonstrate the utility of using optical properties as proxies for fine-scale measurements of biodiversity over large spatial scales.

  17. ASPEN, the Alberta Special Education Network: Using Appropriate Technology to Bring the Community Together.

    Science.gov (United States)

    Hill, W. Leigh; Anthony, Matthew

    1991-01-01

    The Alberta Special Education Network (ASPEN) is a computer-based communications and information network geared to the teaching and learning of exceptional children in rural Alberta, Canada. Network features include toll-free telephone access, a menu-driven user interface, training and awareness, electronic mail, weekly news, forums, and a…

  18. ASPEN Plus in the Chemical Engineering Curriculum: Suitable Course Content and Teaching Methodology

    Science.gov (United States)

    Rockstraw, David A.

    2005-01-01

    An established methodology involving the sequential presentation of five skills on ASPEN Plus to undergraduate seniors majoring in ChE is presented in this document: (1) specifying unit operations; (2) manipulating physical properties; (3) accessing variables; (4) specifying nonstandard components; and (5) applying advanced features. This…

  19. ASPEN+ and economic modeling of equine waste utilization for localized hot water heating via fast pyrolysis

    Science.gov (United States)

    ASPEN Plus based simulation models have been developed to design a pyrolysis process for the on-site production and utilization of pyrolysis oil from equine waste at the Equine Rehabilitation Center at Morrisville State College (MSC). The results indicate that utilization of all available Equine Reh...

  20. Time-domain NMR study of the drying of hemicellulose extracted aspen (Populus tremuloides Michx.)

    Science.gov (United States)

    Thomas Elder; Carl Houtman

    2013-01-01

    The effect of hot water on aspen chips has been evaluated using time-domain low-field nuclear magnetic resonance (NMR) spectroscopy. At moisture contents above fiber saturation point, treated chips exhibit relaxation times of free water longer than for the control. This is consistent with the removal of hemicelluloses given the hydrophilicity of these polysaccharides....

  1. 75 FR 13805 - Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet...

    Science.gov (United States)

    2010-03-23

    ... COMMISSION Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet Communications Corp., Geneva Steel Holdings Corp., Orderpro Logistics, Inc. (n/k/a Securus Renewable Energy, Inc... accurate information concerning the securities of Commercial Concepts, Inc. because it has not filed...

  2. Effects of elevated atmospheric CO2 and/or O3 on intra- and interspecific competitive ability of aspen.

    Science.gov (United States)

    Kubiske, M E; Quinn, V S; Marquardt, P E; Karnosky, D F

    2007-03-01

    Three model communities of trembling aspen (monoculture, and mixed with either paper birch or sugar maple) were grown for seven years in elevated atmospheric CO(2) and O(3) using Free Air CO(2) Enrichment (FACE) technology. We utilized trends in species' importance, calculated as an index of volume growth and survival, as indications of shifting community composition. For the pure aspen communities, different clones emerged as having the highest change in relative importance values depending on the pollutant exposure. In the control and elevated CO(2) treatments, clone 42E was rapidly becoming the most successful clone while under elevated O(3), clone 8 L emerged as the dominant clone. In fact, growth of clone 8 L was greater in the elevated O(3) treatment compared to controls. For the mixed aspen-birch community, importance of aspen and birch changed by - 16 % and + 62 %, respectively, in the controls. In the treatments, however, importance of aspen and birch changed by - 27 % and + 87 %, respectively, in elevated O(3), and by - 10 % and + 45 %, respectively, in elevated CO(2). Thus, the presence of elevated O(3) hastened conversion of stands to paper birch, whereas the presence of elevated CO(2) delayed it. Relative importance of aspen and maple changed by - 2 % and + 3 %, respectively, after seven years in the control treatments. But in elevated O(3), relative importance of aspen and maple changed by - 2 % and + 5 %, respectively, and in elevated CO(2) by + 9 and - 20 %, respectively. Thus, elevated O(3) slightly increases the rate of conversion of aspen stands to sugar maple, but maple is placed at a competitive disadvantage to aspen under elevated CO(2).

  3. Nitrogen balance in soil under eucalyptus plantations

    Directory of Open Access Journals (Sweden)

    Patrícia Anjos Bittencourt Barreto

    2012-08-01

    Full Text Available An understanding of the role of organic nitrogen (N pools in the N supply of eucalyptus plantations is essential for the development of strategies that maximize the efficient use of N for this crop. This study aimed to evaluate the distribution of organic N pools in different compartments of the soil-plant system and their contributions to the N supply in eucalyptus plantations at different ages (1, 3, 5, and 13 years. Three models were used to estimate the contributions of organic pools: Model I considered N pools contained in the litterfall, N pools in the soil microbial biomass and available soil N (mineral N; Model II considered the N pools in the soil, potentially mineralizable N and the export of N through wood harvesting; and Model III (N balance was defined as the difference between the initial soil N pool (0-10 cm and the export of N, taking the application of N fertilizer into account. Model I showed that N pools could supply 27 - 70 % of the N demands of eucalyptus trees at different ages. Model II suggested that the soil N pool may be sufficient for 4 - 5 rotations of 5 years. According to the N balance, these N pools would be sufficient to meet the N demands of eucalyptus for more than 15 rotations of 5 years. The organic pools contribute with different levels of N and together are sufficient to meet the N demands of eucalyptus for several rotations.

  4. Interpreting genotype‐by‐environment interaction for biomass production in hybrid poplars under short‐rotation coppice in Mediterranean environments

    National Research Council Canada - National Science Library

    Sixto, Hortensia; Gil, Paula M; Ciria, Pilar; Camps, Francesc; Cañellas, Isabel; Voltas, Jordi

    2016-01-01

    ...‐rotation coppice poplar plantations. Hybrid poplars are grown for biomass production under a wide range of climatic and edaphic conditions, but their adaptive performance in Mediterranean areas remains poorly characterized...

  5. Change in lignin content during litter decomposition in tropical forest soils (Congo): comparison of exotic plantations and native stands

    Science.gov (United States)

    Bernhard-Reversat, France; Schwartz, Dominique

    1997-09-01

    Fast-growing tree plantations are being extended in tropical countries resulting in new forest ecosystems, the functioning of which is yet not well known. In particular, few data are available concerning lignin decay rate. Lignin, nitrogen and tannin contents of fresh and decaying litter were measured in natural rain forest and in planted stands of Eucalyptus hybrids. Acacia mangium and A. auriculiformisin Congo, together with litter-fall and forest-floor accumulation. Lignin evolution in aging litter exhibited different patterns. Lignin was accumulated under Eucalyptus plantation, but disappeared under natural forest, and was intermediate under Acaciaplantations. The relationships with decomposition rates and lignin degradation factors, such as white rot fungi and termites, are also discussed.

  6. Drought characteristics drive patterns in widespread aspen forest mortality across the western United States

    Science.gov (United States)

    Anderegg, W.; Anderegg, L.; Abatzoglou, J. T.; Berry, J. A.

    2011-12-01

    Widespread drought-induced forest mortality has been documented across the globe in the last few decades and influences land-atmosphere interactions, biodiversity, carbon sequestration, and biophysical and biogeochemical feedbacks to climate change. These rapid mortality events are currently not well-captured in current vegetation models, limiting the ability to predict them. While many studies have focused on the plant physiological mechanisms that mediate vegetation mortality, the characteristics of drought seasonality, sequence, severity and duration that drive mortality events have received much less attention. These characteristics are particularly relevant in light of changing precipitation regimes, changes to snowpack and snowmelt, and increasing temperature stress associated with climate change. We examine the characteristics of drought associated with the recent widespread mortality of trembling aspen (Populus tremuloides) across much of the western United States. We combine a regional model of watershed-level aspen mortality with in situ tissue isotopic analysis of water source to analyze the roles of drought seasonality, severity, and duration in this mortality event, including raw climate variables, derived drought indices, and variables generated by a climate envelope approach. We found that variables pertaining to spring temperatures and spring-summer water deficit, especially during the peak severity of drought, best capture regional mortality patterns, though multi-year drought variables did improve the model. Field water isotopic analysis of aspen water source over a growing season and during moderate seasonal water stress corroborate the regional model by indicating that aspen clones generally utilize surface water with little plasticity during drought stress. These results suggest that drought characteristics can play an important role in mediating widespread forest mortality and have implications for the future vulnerability of trembling aspen

  7. Vertical and horizontal root distribution of mature aspen clones: mechanisms for resource acquisition

    Science.gov (United States)

    Landhäusser, S. M.; Snedden, J.; Silins, U.; Devito, K. J.

    2012-04-01

    Spatial root distribution, root morphology, and intra- and inter-clonal connections of mature boreal trembling aspen clones (Populus tremuloides Michx.) were explored to shed light on the functional relationships between vertical and horizontal distribution of roots and the variation in soil water availability along hill slopes. Root systems of mature aspen were hydraulically excavated in large plots (6 m wide and 12 m long) and to a depth of 30 cm. Most aspen roots were located in the upper 20 cm of the soil and fine and coarse root occupancy was highest in the lower slope positions and lowest towards the upper hill slope position likely because of soil moisture availability. Observation of the root system distribution along the hill slope correlated well with the observation of greater leaf area carried by trees growing at the lower portion of the hill slope. Interestingly, trees growing at the bottom of the slope required also less sapwood area to support the same amount of leaf area of trees growing at the top of a slope. These observations appear to be closely related to soil moisture availability and with that greater productivity at the bottom of the slope. However, trees growing on the upper slope tended to have long lateral roots extending downslope, which suggests long distance water transport through these lateral feeder roots. Genetic analysis indicated that both intra- and inter-clonal root connections occur in aspen, which can play a role in the sharing of resources along moisture gradients. Root systems of boreal aspen growing on upper slope positions exhibited a combination of three attributes (1) asymmetric lateral root systems, that are skewed downslope, (2) deeper taproots, and (3) intra and inter-clonal root connections, which can all be considered adaptive strategies to avoid drought stress in upper slope positions.

  8. Effects of widespread drought-induced aspen mortality on understory plants.

    Science.gov (United States)

    Anderegg, William R L; Anderegg, Leander D L; Sherman, Clare; Karp, Daniel S

    2012-12-01

    Forest die-off around the world is expected to increase in coming decades as temperature increases due to climate change. Forest die-off will likely affect understory plant communities, which have substantial influence on regional biological diversity, ecosystem function, and land-atmosphere interactions, but how die-off alters these plant communities is largely unknown. We examined changes in understory plant communities following a widespread, drought-induced die-off of trembling aspen (Populus tremuloides) in the western United States. We assessed shrub and herbaceous cover and volume in quadrats in 55 plots located across a wide range of levels of aspen mortality. We measured species richness and composition of herbaceous plant communities by recording species presence and absence in 12 sets of paired (1 healthy, 1 dying) aspen plots. Although understory composition in healthy and dying stands was heterogeneous across the landscape, shrub abundance, cover, and volume were higher and abundance of herbaceous species, cover, and volume were lower in dying aspen stands. Shrub cover and volume increased from 2009 to 2011 in dying stands, which suggests that shrub growth and expansion is ongoing. Species richness of herbs declined by 23% in dying stands. Composition of herbs differed significantly between dying and healthy stands. Richness of non-native species did not differ between stand types. The understory community in dying aspen stands was not similar to other shrub-dominated plant communities in the region and may constitute a novel community. Our results suggest that changes in understory plant communities as forests die off could be a significant indirect effect of climate change on biological diversity and forest communities.

  9. Analysis of genetic and environmental effects on hybrid poplar rooting in Central and Northern Minnesota, USA

    Science.gov (United States)

    Ronald S., Jr. Zalesny; Don Riemenschneider; Edmund Bauer

    2000-01-01

    We studied genetic and environmental effects on adventitious root initiation and growth because rooting is biologically prerequisite to the establishment of hybrid poplar plantations. Six clones from two pedigrees (pure Populus deltoides "cottonwoods" and P. deltoides x P. maximowiczii hybrids) were...

  10. Regional Mapping of Plantation Extent Using Multisensor Imagery

    Science.gov (United States)

    Torbick, N.; Ledoux, L.; Hagen, S.; Salas, W.

    2016-12-01

    Industrial forest plantations are expanding rapidly across the tropics and monitoring extent is critical for understanding environmental and socioeconomic impacts. In this study, new, multisensor imagery were evaluated and integrated to extract the strengths of each sensor for mapping plantation extent at regional scales. Three distinctly different landscapes with multiple plantation types were chosen to consider scalability and transferability. These were Tanintharyi, Myanmar, West Kalimantan, Indonesia, and southern Ghana. Landsat-8 Operational Land Imager (OLI), Phased Array L-band Synthetic Aperture Radar-2 (PALSAR-2), and Sentinel-1A images were fused within a Classification and Regression Tree (CART) framework using random forest and high-resolution surveys. Multi-criteria evaluations showed both L-and C-band gamma nought γ° backscatter decibel (dB), Landsat reflectance ρλ, and texture indices were useful for distinguishing oil palm and rubber plantations from other land types. The classification approach identified 750,822 ha or 23% of the Taninathryi, Myanmar, and 216,086 ha or 25% of western West Kalimantan as plantation with very high cross validation accuracy. The mapping approach was scalable and transferred well across the different geographies and plantation types. As archives for Sentinel-1, Landsat-8, and PALSAR-2 continue to grow, mapping plantation extent and dynamics at moderate resolution over large regions should be feasible.

  11. The State and the Development of Industrial Plantation Forest

    Directory of Open Access Journals (Sweden)

    Sudarmalik Sudarmalik

    2015-02-01

    Full Text Available Development of industrial plantation forest is a form of principal-agent relationship, in which the Ministry of Forestry as a principal gives utilization permit to the entrepreneur as an agent, known as the Forest Timber Product Exploitation Permit on Planted Forest. This utilization permit obtained by the agents is operationally conducted by other parties through a cooperative agreement. The purpose of this study is to obtain an information regarding to the state position in the development of industrial plantation forest. The study was conducted in Riau Province, using the constructivist paradigm with phenomenological method. Data were obtained through in-depth interviews to selected informants. Data were also obtained from the review of documents to complement the interview. Data analysis was conducted using property rights and principal agent theories. The phenomenon of multi-chain transfer of the management rights of plantation forest that occoured in the observed companies showed that the state was unable to effectively control to the forest plantation. The study recommends that state should issue regulation to decrease or stops further transfer of the management rights of plantation forest. However, further study needs to overcome the existing over accumulation of plantation forest in a few hands.Keywords: industrial plantation forest, property right, principal agent, the state position, authority

  12. 利用Aspen Plus 7.3进行严格精馏过程模拟%The Simulation of Strict Distillation Process Using Aspen Plus 7.3

    Institute of Scientific and Technical Information of China (English)

    薛科创

    2014-01-01

    化工过程模拟是通过计算机对化工生产过程的再现,由于计算量大,必须通过相应的化工模拟软件来实现.Aspen Plus,尤其是Aspen Plus 7.3,由于其计算精确、运行速度快,成为化工设计者的首选软件.本文通过介绍利用Aspen Plus 7.3进行严格精馏模拟,说明了严格精馏模拟的应用范围以及利用Aspen Plus 7.3进行严格精馏模拟的方法.

  13. Ecosystem functions of oil palm plantations - a review

    OpenAIRE

    Dislich, Claudia; Keyel, Alexander C.; Salecker, Jan; Kisel, Yael; Meyer, Katrin M.; Corre, Marife D.; Faust, Heiko; Hess, Bastian; Knohl, Alexander; Kreft, Holger; Meijide, Ana; Nurdiansyah, Fuad; Otten, Fenna; Pe'er, Guy; Steinebach, Stefanie

    2015-01-01

    Oil palm plantations have expanded rapidly in the last decades. This large-scale land-use change has had great impacts on both the areas converted to oil palm and their surroundings. Howev-er, research on the impacts of oil palm agriculture is scattered and patchy, and no clear overview ex-ists. Here, we address this gap through a systematic and comprehensive literature review of all ecosys-tem functions in oil palm plantations. We compare ecosystem functions in oil palm plantations to those ...

  14. The Carbon Sequestration Potential of Tree Crop Plantations

    DEFF Research Database (Denmark)

    Kongsager, Rico; Napier, Jonas; Mertz, Ole

    2013-01-01

    C/ha) and orange (76 tC/ha) plantations have a much lower C content, and oil palm (45 tC/ha) has the lowest C potential, assuming that the yield is not used as biofuel. There is considerable C sequestration potential in plantations if they are established on land with modest C content such as degraded forest......), oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and orange (Citrus sinesis) – cultivated in the tropics. Measurements were conducted in Ghana and allometric equations were applied to estimate biomass. The largest C potential was found in the rubber plantations (214 tC/ha). Cocoa (65 t...

  15. Aspen Plus Software Applies to Technological Transformation of Trichlorosilane Synthesis%Aspen Plus软件在三氯氢硅低压合成技术改造中的应用

    Institute of Scientific and Technical Information of China (English)

    刘兴平

    2014-01-01

    利用化工模拟软件Aspen Plus对三氯氢硅合成装置进行全流程模拟,并在此基础上完成了该系统的技术改造.Aspen Plus软件为系统工艺改造提供了可靠的基础数据,大大提高了改造的成功性.

  16. How to Create, Modify, and Interface Aspen In-House and User Databanks for System Configuration 2:

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D W

    2000-10-27

    The goal of this document is to provide detailed instructions to create, modify, interface, and test Aspen User and In-House databanks with minimal frustration. The level of instructions are aimed at a novice Aspen Plus simulation user who is neither a programming nor computer-system expert. The instructions are tailored to Version 10.1 of Aspen Plus and the specific computing configuration summarized in the Title of this document and detailed in Section 2. Many details of setting up databanks depend on the computing environment specifics, such as the machines, operating systems, command languages, directory structures, inter-computer communications software, the version of the Aspen Engine and Graphical User Interface (GUI), and the directory structure of how these were installed.

  17. How to Create, Modify, and Interface Aspen In-House and User Databanks for System Configuration 1:

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D W

    2000-10-27

    The goal of this document is to provide detailed instructions to create, modify, interface, and test Aspen User and In-House databanks with minimal frustration. The level of instructions are aimed at a novice Aspen Plus simulation user who is neither a programming nor computer-system expert. The instructions are tailored to Version 10.1 of Aspen Plus and the specific computing configuration summarized in the Title of this document and detailed in Section 2. Many details of setting up databanks depend on the computing environment specifics, such as the machines, operating systems, command languages, directory structures, inter-computer communications software, the version of the Aspen Engine and Graphical User Interface (GUI), and the directory structure of how these were installed.

  18. Pesticide pollution status in cocoa plantation soil

    Directory of Open Access Journals (Sweden)

    E. Atuanya

    2017-09-01

    Full Text Available Management of cocoa plantation field relied on the use of pesticides over the years; hence, the fate of such chemicals is one of the most debated issues among the stakeholders. Young and old cocoa plantation fields from 4 major cocoa producing States in Nigeria were selected as the study area. Eight composites soil samples collected from 3 portions of 6 transect measured area (100 x 50m of the field were transported to the laboratory in sterile glass jar for analysis. A total of 19 organochlorine pesticides residues; (aldrin, α-hexachlorohexane, β-hexachlorohexane, γ-hexachlorohexane, δ-hexachlorohexane, α-chlordane, γ-chlordane, p,p’-dichlorodiphenyldichloroethane, p,p’-dichlorodiphenyldichloroethylene, p,p’-dichlorodiphenyltrichloroethane, dieldrin, endosulfan I, endosulfan-II, endosulfan sulfate, endrin, endrin aldehydes, heptachlor, heptachlor epoxide and metoxychlor were analyzed with gas chromatography equipped with electron capture detector. The results revealed the variation in the number of residues detected among the study fields. Endosulfan-I had the highest value g organochlorine pesticides residue detected. Most of the residue concentrations were within the European Union regulatory standard of Czech Republic. Other-cyclodine group had the highest concentration value among the evaluated organochlorine pesticides groups. The significant (P < 0.05 higher concentration of total organochlorine pesticides were observed in old fields. Composition quotients values indicate that most of the observed organochlorine pesticides residues were products of historical usage. There were strong correlations among the total organic carbon contents of soils and the total organochlorine pesticides compounds. Government regulatory agencies are encouraged to vigorously embark in further monitoring and ensuring the safety compliance of farmers towards the use of pesticides in Nigeria farms.

  19. Transcriptome responses to aluminum stress in roots of aspen (Populus tremula

    Directory of Open Access Journals (Sweden)

    Grisel Nadine

    2010-08-01

    Full Text Available Abstract Background Ionic aluminum (mainly Al3+ is rhizotoxic and can be present in acid soils at concentrations high enough to inhibit root growth. Many forest tree species grow naturally in acid soils and often tolerate high concentrations of Al. Previously, we have shown that aspen (Populus tremula releases citrate and oxalate from roots in response to Al exposure. To obtain further insights into the root responses of aspen to Al, we investigated root gene expression at Al conditions that inhibit root growth. Results Treatment of the aspen roots with 500 μM Al induced a strong inhibition of root growth within 6 h of exposure time. The root growth subsequently recovered, reaching growth rates comparable to that of control plants. Changes in gene expression were determined after 6 h, 2 d, and 10 d of Al exposure. Replicated transcriptome analyses using the Affymetrix poplar genome array revealed a total of 175 significantly up-regulated and 69 down-regulated genes, of which 70% could be annotated based on Arabidopsis genome resources. Between 6 h and 2 d, the number of responsive genes strongly decreased from 202 to 26, and then the number of changes remained low. The responses after 6 h were characterized by genes involved in cell wall modification, ion transport, and oxidative stress. Two genes with prolonged induction were closely related to the Arabidopsis Al tolerance genes ALS3 (for Al sensitive 3 and MATE (for multidrug and toxin efflux protein, mediating citrate efflux. Patterns of expression in different plant organs and in response to Al indicated that the two aspen genes are homologs of the Arabidopsis ALS3 and MATE. Conclusion Exposure of aspen roots to Al results in a rapid inhibition of root growth and a large change in root gene expression. The subsequent root growth recovery and the concomitant reduction in the number of responsive genes presumably reflect the success of the roots in activating Al tolerance mechanisms. The

  20. Influence of Lateral Flow on the Predisposition of Aspen Mortality during Drought

    Science.gov (United States)

    Tai, X.; Mackay, D. S.; Anderegg, W.; Sperry, J. S.

    2014-12-01

    Lateral subsurface flow can be critical to understanding the spatial soil moisture availability to plants, and when, where, and how drought are influencing individual plants. The concentration of intensive aspen damage in certain hillslopes with higher temperature and lower soil moisture suggests that soil augmentation/reduction from lateral redistribution could help explain the survivability of some aspen through its influence on soil water availability during drought. It remains unclear how lateral water redistribution helps to limit hydraulic impairment of aspen located in different topographic positions during a drought event. This study employed an integrated ecohydrology model, TREES, combining plant-water balance and canopy physiology, to examine the potential effects of lateral flow on hydraulic and metabolic performance of aspen, by exposing trees to a set of soil water conditions associated with different levels of water stress. Sap flux, soil moisture, meteorological and plant hydraulic data from aspen trees in Colorado that died (SAD) and those that lived were used to parameterize the model. Our goal was to quantify the extent to which lateral flow explained sudden aspen dieback. The results indicate that the predisposition of tree mortality is related to the level of soil water augmentation. A reduction of 30% soil water content could introduce 21.55% increase in the loss of hydraulic conductivity (PLC), 23.6% loss in canopy transpiration, 21.7% loss in GPP. It would also cause the frequency of greater than 50% PLC to increase from 42.1% of the time to 51% of the time, and the frequency of hitting the 88% PLC pressure to increase from 11% to 14% of the time. On the other hand, an augment of 30% soil water content could introduce 20.2% reduction in PLC, 16.4% gain in canopy transpiration, 16.5% gain in GPP. The frequency of greater than 50% PLC is reduced to 31% of the time and the frequency of hitting the 88% PLC pressure is reduced to 6% of the time

  1. Coupling aquaculture with forest plantations for food, energy, and water resiliency.

    Science.gov (United States)

    Shifflett, Shawn Dayson; Culbreth, Allison; Hazel, Dennis; Daniels, Harry; Nichols, Elizabeth Guthrie

    2016-11-15

    Freshwater aquaculture and forest bioenergy markets are expanding globally in areas concurrently experiencing human population growth, urbanization and water shortages. Coupling these agroecosystems can improve food, energy, and water resiliency by enhancing ecosystem services through fertilization, water-reuse, carbon storage, and bioenergy via biomass production. This study evaluated how a model aquaculture-managed forest plantation could (1) provision fish and woody biomass; (2) regulate carbon, groundwater infiltration, and groundwater quality; and (3) support nutrient cycling over a two-year period. A 0.5-hectare hardwood bioenergy plantation was established with 12 Populus spp. genotypes adjacent to a 0.6-hectare freshwater aquaculture operation (hybrid striped bass, Morone chrysops×M. saxatilis); pond waters were land-applied on the plantation for two years. The aquaculture operation produced ~3.5Mg of fish and trees yielded 5.9Mgha(-1)yr(-1) of oven-dry biomass, sequestered 2.9Mg carbon (C) ha(-1)yr(-1) and stored 0.028Mg nitrogen (N) ha(-1)yr(-1). Biomass productivity, carbon storage, and nitrogen storage differed significantly among the evaluated Populus genotypes. Land application of pond water increased groundwater infiltration by 60% relative to the previous year. The integrated system regulated chlorophyll a, total organic carbon, and nitrogen in groundwater at concentrations below regulatory limits. This study demonstrated that coupled agroecosystems could deliver productive yields of food and bioenergy as well as support water re-use while meeting water quality regulations. More research is needed to evaluated long-term sustainability and economic viability of this coupled system and other land management practices that seek to improve food, energy, and water resiliency. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. The efficacy of six elite isolates of the fungus Chondrostereum purpureum against the sprouting of European aspen.

    Science.gov (United States)

    Hamberg, Leena; Hantula, Jarkko

    2016-04-15

    The sprouting of broad-leaved trees after cutting is problematic in forest regeneration areas, along roads and railways, under electric power and above gas pipe lines. In Finland, one of the most difficult species to control in these areas is the European aspen (Populus tremula), which produces both stump sprouts and root suckers after saplings have been cut. In this study, we investigated whether a decay fungus of broad-leaved trees, Chondrostereum purpureum, could be used as a biological control agent against aspen sprouting. The efficacy of six elite strains of C. purpureum (improved earlier in a breeding process) was investigated on aspen for three years. The most efficient C. purpureum strain, R53, tested earlier on birch (Betula pendula and B. pubescens), was efficient in causing mortality of aspen stumps and preventing the development of root suckers. With this strain, stump mortality was 78%, while significantly lower in control stumps which were cut only (47%). Aspen trees in the vicinity of the treatments (within a 10 m radius around each sapling) decreased the efficacy of C. purpureum. This study shows that the decay fungus C. purpureum can successfully be used in the sprout control of aspen saplings.

  3. Carbon storage in eucalyptus and pine plantations in South Africa

    CSIR Research Space (South Africa)

    Christie, SI

    1995-11-01

    Full Text Available Carbon (C) is stored by plantation forests either when ecosystems with a low C density (such as tropical grasslands) are afforested or when timber is converted to semi permanent products. If the afforestation rate is relatively constant...

  4. Selected Harvesting Machines For Short Rotation Intensive Culture Biomass Plantations

    Science.gov (United States)

    Sammy Woodfin; Doug Frederick; Bryce Stokes

    1987-01-01

    Three different harvesting systems were observed and analyzed for productivity and costs in a short rotation.intensive culture plantation of 2 to 5 year old sycamore. Individual machines were compared to create an optimum system.

  5. Plantation Patriarchy and Structural Violence: Women Workers in Sri Lanka

    NARCIS (Netherlands)

    R. Kurian (Rachel); K. Jayawardena (Kumari)

    2013-01-01

    markdownabstract__Abstract__ Plantation production began in Sri Lanka in the early 19th century under British colonial rule, when the government provided financial incentives and infrastructural support for the commercialisation and export of agricultural crops in line with promoting

  6. Characterization of weed flora in rubber trees plantations of Bongo ...

    African Journals Online (AJOL)

    SARAH

    2013-10-31

    Oct 31, 2013 ... of 1 and 2 years old, weeds were dominated by leguminous cover crop Pueraria phaseoloides (Roxb.) Benth. ... diminish the growth of the tree by up to 50% (Grist ... diversity of the plantation, (2) analyze the evolution.

  7. Understory succession in post-agricultural oak plantations

    DEFF Research Database (Denmark)

    Brunet, Jörg; Valtinat, Karin; Mayr, Marian Lajos

    2011-01-01

    -agricultural plantation forests. We studied effects of stand age, forest fragmentation, and soil and canopy conditions on species richness and abundance of four species groups in the understory of post-arable oak plantations in southern Sweden: herbaceous forest specialists, habitat generalists and open land species......, and woody species. The group of forest specialists may approach the richness of continuously forested sites after 60-80 years in non-fragmented plantations, but many forest species were sensitive to habitat fragmentation. Open-land species richness decreased during succession, while the richness of woody...... species and of generalists remained stable, and were not affected by fragmentation. Abundance of generalists gradually decreased in non-fragmented plantations, probably due to competition from colonizing forest specialists. Soil pH in post-arable stands remained consistently higher than in continuously...

  8. Technological Simulation and Optimizing Design of Atmospheric Distillation Column by ASPEN PLUS Software%ASPEN PLUS模拟常压塔装置设计优化

    Institute of Scientific and Technical Information of China (English)

    刘呈军

    2013-01-01

    本文采用ASPEN PLUS软件对大庆原油常压塔部分操作工况进行了工艺模拟计算.模拟结果表明,实际操作中的塔操作条件、总物料平衡、产品质量等指标与工艺设计吻合较好,为大型常压塔的设计选型提供了参考依据.

  9. 工业系统流程模拟利器--ASPEN PLUS%Introduction of a Useful Industrial Flowsheet Simulation Program, ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    赵琛琛

    2003-01-01

    流程模拟软件的功效在于依托精确的模型、科学的计算方法对单元和系统进行计算和高效的优化设计.在已经开发成功的模拟软件中,ASPEN PLUS是比较先进的,在大型化工和热工系统模拟中更展现了它的优势.概括介绍了这款软件的功能和使用方法.

  10. Process simulation for the rectification of vinyl chloride based on ASPEN PLUS%基于ASPEN PLUS的氯乙烯精馏过程的模拟

    Institute of Scientific and Technical Information of China (English)

    李群生; 刘阳

    2008-01-01

    应用ASPEN PLUS化工模拟系统中的RADFRAC精馏模块对氯乙烯精馏中的高低沸塔进行模拟,模拟值与实际值基本吻合.讨论了回流比、进料位置、馏出比等参数对精馏的影响,获得了对氯乙烯精馏具有指导意义的相关工艺数据.

  11. Simulation analysis of distillation of dichloroethane by using ASPEN PLUS%二氯乙烷精馏过程的ASPEN PLUS模拟分析

    Institute of Scientific and Technical Information of China (English)

    钱启蒙

    2015-01-01

    利用化工流程模拟软件Aspen Plus对二氯乙烷(EDC)精制单元进行模拟研究.针对工艺流程改变后EDC纯度不达标的问题,提出了新的模拟优化方案.模拟结果表明:通过将脱重塔部分出料重新送入脱轻塔,改变脱轻塔进料组成,能有效提高EDC纯度.

  12. Results of the 2000 Creek Plantation Swamp Survey

    Energy Technology Data Exchange (ETDEWEB)

    Fledderman, P.D.

    2000-10-30

    This report is a survey of the Creek Plantation located along the Savannah River and borders the southeast portion of the Savannah River Site. The land is primarily undeveloped and agricultural; its purpose is to engage in equestrian-related operations. A portion of Creek Plantation along the Savannah River is a low-lying swamp, known as the Savannah River Swamp, which is uninhabited and not easily accessible.

  13. Nutrient Management for Eucalypt Plantations in South China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Eucalypts are very popular for revegetation in many parts of south China because of their capacity to tolerate degraded sites and unfertile soils,and their fast growth potential to coppice. This paper reviews a decade of field trials in china, undertaken as part of several bilateral researchprograms in plantation forestry, concerning the use of fertilizers, harvest residue management and inoculation with ectomycorrhizal fungi. One of the key questions addressed is whether the productivity of plantation ...

  14. Plantation Forests for Sustainable Wood Supply and Development in China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With the implementation of Natural Forests Protection Program, wood resource base in China is shifting from naturally grown forests to plantation forests. This paper reviews: 1) The evolution of Chinese decade-long reforestation program and its contribution to sustainable wood supply and development, and 2) impacts of "China's Natural Forest Protection Program and " Fast-Growing and High-Yield Plantation Program in China " on China's wood supply and sustainability. In addition, this paper highlights Chi...

  15. Yaughan and Curriboo Plantations. Studies in Afro-American Archaeology,

    Science.gov (United States)

    1983-04-01

    Publfc Transportation, Columbia, South Carolina. Charleston Probate Records 1671- Record of Wills. South Carolina Department of Archives and 1863 History...York. Wheaton, Thomas R., Jr. 1976 La ceramica clasica del area de Huejotzingo, Puebla . Comunicaciones. 13:25-32. 1980 Architecture at Curriboo and...1858, Deed Book L-14, p. 244, RMC). Thurston retained part of the old Yaughan Plantation; in 1863 , a sale of land contained in Curriboo plantation

  16. Intensive plantation culture: 12 years research

    Science.gov (United States)

    Edward A. Hansen

    1983-01-01

    A collection of papers summarize the status of knowledge for growing hybrid poplars in a short rotation intensively cultured system. The research included studies of propagation, physiology, culture, engineering, insects and diseases, and economics.

  17. [Selection of biomass estimation models for Chinese fir plantation].

    Science.gov (United States)

    Li, Yan; Zhang, Jian-guo; Duan, Ai-guo; Xiang, Cong-wei

    2010-12-01

    A total of 11 kinds of biomass models were adopted to estimate the biomass of single tree and its organs in young (7-year-old), middle-age (16-year-old), mature (28-year-old), and mixed-age Chinese fir plantations. There were totally 308 biomass models fitted. Among the 11 kinds of biomass models, power function models fitted best, followed by exponential models, and then polynomial models. Twenty-one optimal biomass models for individual organ and single tree were chosen, including 18 models for individual organ and 3 models for single tree. There were 7 optimal biomass models for the single tree in the mixed-age plantation, containing 6 for individual organ and 1 for single tree, and all in the form of power function. The optimal biomass models for the single tree in different age plantations had poor generality, but the ones for that in mixed-age plantation had a certain generality with high accuracy, which could be used for estimating the biomass of single tree in different age plantations. The optimal biomass models for single Chinese fir tree in Shaowu of Fujin Province were used to predict the single tree biomass in mature (28-year-old) Chinese fir plantation in Jiangxi Province, and it was found that the models based on a large sample of forest biomass had a relatively high accuracy, being able to be applied in large area, whereas the regional models with small sample were limited to small area.

  18. The State and the Development of Industrial Plantation Forest

    Directory of Open Access Journals (Sweden)

    Sudarmalik

    2014-12-01

    Full Text Available Development of industrial plantation forest is a form of principal-agent relationship, in which the Ministry of Forestry as a principal gives utilization permit to the entrepreneur as an agent, known as the Forest Timber Product Exploitation Permit on Planted Forest. This utilization permit obtained by the agents is operationally conducted by other parties through a cooperative agreement. The purpose of this study is to obtain an information regarding to the state position in the development of industrial plantation forest. The study was conducted in Riau Province, using the constructivist paradigm with phenomenological method. Data were obtained through in-depth interviews to selected informants. Data were also obtained from the review of documents to complement the interview. Data analysis was conducted using property rights and principal agent theories. The phenomenon of multi-chain transfer of the management rights of plantation forest that occoured in the observed companies showed that the state was unable to effectively control to the forest plantation. The study recommends that state should issue regulation to decrease or stops further transfer of the management rights of plantation forest. However, further study needs to overcome the existing over accumulation of plantation forest in a few hands.

  19. Transmission of Leishmania in coffee plantations of Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Bruce Alexander

    2002-07-01

    Full Text Available Transmission of Leishmania was studied in 27 coffee plantations in the Brazilian State of Minas Gerais. Eighteen females and six males (11.6% of the people tested, aged between 7-65 gave a positive response to the Montenegro skin test. Awareness of sand flies based on the ability of respondents to identify the insects using up to seven predetermined characteristics was significantly greater among inhabitants of houses occupied by at least one Mn+ve individual. Five species of phlebotomine sand fly, including three suspected Leishmania vectors, were collected within plantations under three different cultivation systems. Four of these species i.e., Lu. fischeri (Pinto 1926, Lu. migonei (França 1920, Lu. misionensis (Castro 1959 and Lutzomyia whitmani (Antunes & Coutinho 1939 were collected in an organic plantation and the last of these was also present in the other two plantation types. The remaining species, Lu. intermedia (Lutz & Neiva 1912, was collected in plantations under both the "adensado" and "convencional" systems. The results of this study indicate that transmission of Leishmania to man in coffee-growing areas of Minas Gerais may involve phlebotomine sand flies that inhabit plantations.

  20. Effect of Continuous Plantation of Chinese Fir on Soil Fertility

    Institute of Scientific and Technical Information of China (English)

    DINGYING-XIANG; CHENJIN-LIN

    1995-01-01

    The changes in soil fertility under continuous plantation of Chinese fir were studied by comparing soil samples from different forest stands:the first and second plantations of Chinese fir,evergreen broad-leaved forests,and clear-cut and burnt Chinese fir land located at Xihou Village,Nanping of Fujian Province.The soils were humic red soil originated from weathered coarse granite of the Presinian system.Soil pH,CEC,base saturation ,exchangeable Ca2+,exchangeable Mg2+ and A1-P declined after continuous plantation of Chinese fir.The same trends were also found in the soils under broad-leaved stands and slash burnt lands.The explantation was that not merely the biological nature of the Chinese fir itself but the natural leaching of nutrients,soil erosion and nutrient losses due to clear cutting and slash burning of the preceduing plantation caused the soil deterioration .Only some of main soil nutrients decreased after continuous plantation of Chinese fir,depending on specific silvicultural system,which was different from the conclusions in some other reports which showed that all main nutrients,such as OM,total N,available P and available K decreased,Some neccessary step to make up for the lost base,to apply P fertilizer and to avoid buring on clear cut lands could be taken to prevent soil degradation and yield decline in the system of continuous plantation of Chinese fir.

  1. Food Preferences of the Rubber Plantation Litter Beetle, Luprops tristis, a Nuisance Pest in Rubber Tree Plantations

    National Research Council Canada - National Science Library

    Thomas K. Sabu; K.V. Vinod

    2009-01-01

    .... Ready availability of the preferred, prematurely fallen, tender rubber tree leaves as a food resource is suggested as being responsible for the exceptionally high abundance of L. tristis in rubber tree plantation belts.

  2. Standardized Competencies for Parenteral Nutrition Order Review and Parenteral Nutrition Preparation, Including Compounding: The ASPEN Model.

    Science.gov (United States)

    Boullata, Joseph I; Holcombe, Beverly; Sacks, Gordon; Gervasio, Jane; Adams, Stephen C; Christensen, Michael; Durfee, Sharon; Ayers, Phil; Marshall, Neil; Guenter, Peggi

    2016-08-01

    Parenteral nutrition (PN) is a high-alert medication with a complex drug use process. Key steps in the process include the review of each PN prescription followed by the preparation of the formulation. The preparation step includes compounding the PN or activating a standardized commercially available PN product. The verification and review, as well as preparation of this complex therapy, require competency that may be determined by using a standardized process for pharmacists and for pharmacy technicians involved with PN. An American Society for Parenteral and Enteral Nutrition (ASPEN) standardized model for PN order review and PN preparation competencies is proposed based on a competency framework, the ASPEN-published interdisciplinary core competencies, safe practice recommendations, and clinical guidelines, and is intended for institutions and agencies to use with their staff.

  3. Aspen Plus软件在工业上的应用

    Institute of Scientific and Technical Information of China (English)

    牛毓

    2014-01-01

    Aspen Plus软件是一款重要的工流程模拟软件,该软件应用范围广泛,在传热领域、精馏领域以及化工领域等方面都有应用,尤其是在化工模拟领域应用最广。本文主要对Aspen Plus软件功能进行了介绍,介绍了该软件在工业上的应用情况,并重点介绍了其在化工行业的应用。

  4. Enzymatic hydrolysis of aspen biomass into fermentable sugars by using lignocellulases from Armillaria gemina.

    Science.gov (United States)

    Jagtap, Sujit Sadashiv; Dhiman, Saurabh Sudha; Kim, Tae-Su; Li, Jinglin; Lee, Jung-Kul; Kang, Yun Chan

    2013-04-01

    A white rot fungus, identified as Armillaria gemina SKU2114 on the basis of morphological and phylogenetic analyses, was found to secrete efficient lignocellulose-degrading enzymes. The strain showed maximum endoglucanase, cellobiohydrolase, and β-glucosidase activities of 146, 34, and 15 U/mL, respectively, and also secreted xylanase, laccase, mannanase, and lignin peroxidase with activities of 1270, 0.16, 57, and 0.31 U/mL, respectively, when grown with rice straw as a carbon source. Among various plant biomasses tested for saccharification, aspen biomass produced the maximum amount of reducing sugar. Response surface methodology was used to optimize the hydrolysis of aspen biomass to achieve the highest level of sugar production. A maximum saccharification yield of 62% (429 mg/g-substrate) was obtained using Populus tomentiglandulosa biomass after 48 h of hydrolysis. A. gemina was shown to be a good option for use in the production of reducing sugars from lignocellulosic biomass.

  5. Lignin depolymerization/repolymerization and its critical role for delignification of aspen wood by steam explosion.

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2007-11-01

    Steam explosion is an important process for the fractionation of biomass components. In order to understand the behaviour of lignin under the conditions encountered in the steam explosion process, as well as in other types of steam treatment, aspen wood and isolated lignin from aspen were subjected to steam treatment under various conditions. The lignin portion was analyzed using NMR and size exclusion chromatography as major analytical techniques. Thereby, the competition between lignin depolymerization and repolymerization was revealed and the conditions required for these two types of reaction identified. Addition of a reactive phenol, 2-naphthol, was shown to inhibit the repolymerization reaction strongly, resulting in a highly improved delignification by subsequent solvent extraction and an extracted lignin of uniform structure.

  6. THE FOREST-ATMOSPHERIC CARBON TRANSFER AND STORAGE-II (FACTS-II): ASPEN FACE PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    KARNOSKY,D.F.; HENDREY,G.; PREGITZER,K.; ISEBRANDS,J.G.

    1998-02-01

    The FACTS II (ASPEN FACE) infrastructure including 12 FACE [Free-Air Carbon dioxide Enrichment] rings, a central control facility, a central CO{sub 2} and O{sub 2} receiving and storage area, a central O{sub 3} generation system, and a dispensing system for CO{sub 2} and O{sub 3} was completed in 1997. The FACE rings were planted with over 10,000 plants (aspen, birch and maple). The entire system was thoroughly tested for both CO{sub 2} and O{sub 3} and was shown to be effective in delivering elevated CO{sub 2} and/or O{sub 3} on demand and at predetermined set points. The NCASI support to date has been extremely helpful in matching support for federal grants.

  7. The Forest-Atmospheric Carbon Transfer and Storage-II (FACTS-II): Aspen FACE project

    Energy Technology Data Exchange (ETDEWEB)

    Karnosky, D.F.; Pregitzer, K. [Michigan Technological Univ., Houghton, MI (United States). School of Forestry and Wood Products; Hendrey, G. [Brookhaven National Lab., Upton, NY (United States); Isebrands, J.G. [Forest Service, Rhinelander, WI (United States)

    1998-02-01

    The FACTS II (Aspen FACE) infrastructure including 12 FACE rings, a central control facility, a central CO{sub 2} and O{sub 3} receiving and storage area, a central O{sub 3} generation system, and a dispensing system for CO{sub 2} and O{sub 3} was completed in 1997. The FACE rings were planted with over 10,000 plants (aspen, birch and maple). The entire system was thoroughly tested for both CO{sub 2} and O{sub 3} and was shown to be effective in delivering elevated CO{sub 2} and/or O{sub 3} on demand and at predetermined set points. The NCASI support to date has been extremely helpful in matching support for federal grants.

  8. Genetic Augmentation of Syringyl Lignin in Low-lignin Aspen Trees, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Chung-Jui Tsai; Mark F. Davis; Vincent L. Chiang

    2004-11-10

    As a polysaccharide-encrusting component, lignin is critical to cell wall integrity and plant growth but also hinders recovery of cellulose fibers during the wood pulping process. To improve pulping efficiency, it is highly desirable to genetically modify lignin content and/or structure in pulpwood species to maximize pulp yields with minimal energy consumption and environmental impact. This project aimed to genetically augment the syringyl-to-guaiacyl lignin ratio in low-lignin transgenic aspen in order to produce trees with reduced lignin content, more reactive lignin structures and increased cellulose content. Transgenic aspen trees with reduced lignin content have already been achieved, prior to the start of this project, by antisense downregulation of a 4-coumarate:coenzyme A ligase gene (Hu et al., 1999 Nature Biotechnol 17: 808- 812). The primary objective of this study was to genetically augment syringyl lignin biosynthesis in these low-lignin trees in order to enhance lignin reactivity during chemical pulping. To accomplish this, both aspen and sweetgum genes encoding coniferaldehyde 5-hydroxylase (Osakabe et al., 1999 PNAS 96: 8955-8960) were targeted for over-expression in wildtype or low-lignin aspen under control of either a constitutive or a xylem-specific promoter. A second objective for this project was to develop reliable and cost-effective methods, such as pyrolysis Molecular Beam Mass Spectrometry and NMR, for rapid evaluation of cell wall chemical components of transgenic wood samples. With these high-throughput techniques, we observed increased syringyl-to-guaiacyl lignin ratios in the transgenic wood samples, regardless of the promoter used or gene origin. Our results confirmed that the coniferaldehyde 5-hydroxylase gene is key to syringyl lignin biosynthesis. The outcomes of this research should be readily applicable to other pulpwood species, and promise to bring direct economic and environmental benefits to the pulp and paper industry.

  9. The Impact of Nitrogen Limitation and Mycorrhizal Symbiosis on Aspen Tree Growth and Development

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Bich Thi Ngoc [Univ. of Alabama, Huntsville, AL (United States)

    2014-08-18

    Nitrogen deficiency is the most common and widespread nutritional deficiency affecting plants worldwide. Ectromycorrhizal symbiosis involves the beneficial interaction of plants with soil fungi and plays a critical role in nutrient cycling, including the uptake of nitrogen from the environment. The main goal of this study is to understand how limiting nitrogen in the presence or absence of an ectomycorrhizal fungi, Laccaria bicolor, affects the health of aspen trees, Populus temuloides.

  10. Vegetation, land surface brightness, and temperature dynamics after aspen forest die-off

    Science.gov (United States)

    Huang, Cho-ying; Anderegg, William R. L.

    2014-07-01

    Forest dynamics following drought-induced tree mortality can affect regional climate through biophysical surface properties. These dynamics have not been well quantified, particularly at the regional scale, and are a large uncertainty in ecosystem-climate feedback. We investigated regional biophysical characteristics through time (1995-2011) in drought-impacted (2001-2003), trembling aspen (Populus tremuloides Michx.) forests by utilizing Landsat time series green and brown vegetation cover, surface brightness (total shortwave albedo), and daytime land surface temperature. We quantified the temporal dynamics and postdrought recovery of these characteristics for aspen forests experiencing severe drought-induced mortality in the San Juan National Forest in southwestern Colorado, USA. We partitioned forests into three categories from healthy to severe mortality (Healthy, Intermediate, and Die-off) by referring to field observations of aspen canopy mortality and live aboveground biomass losses. The vegetation cover of die-off areas in 2011 (26.9% of the aspen forest) was significantly different compared to predrought conditions (decrease of 7.4% of the green vegetation cover and increase of 12.1% of the brown vegetation cover compared to 1999). The surface brightness of the study region 9 years after drought however was comparable to predrought estimates (12.7-13.7%). Postdrought brightness was potentially influenced by understory shrubs, since they became the top layer green canopies in disturbed sites from a satellite's point of view. Satellite evidence also showed that the differences of land surface temperature among the three groups increased substantially (≥45%) after drought, possibly due to the reduction of plant evapotranspiration in the Intermediate and Die-off sites. Our results suggest that the mortality-affected systems have not recovered in terms of the surface biophysical properties. We also find that the temporal dynamics of vegetation cover holds

  11. Aquatic ecosystem response to timber harvesting for the purpose of restoring aspen.

    Science.gov (United States)

    Jones, Bobette E; Krupa, Monika; Tate, Kenneth W

    2013-01-01

    The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003-2010) involved two projects located in Lassen National Forest. The Pine-Bogard Project consisted of three treatments adjacent to Pine and Bogard Creeks: (i) Phase 1 in January 2004, (ii) Phase 2 in August 2005, and (iii) Phase 3 in January 2008. The Bailey Project consisted of one treatment adjacent to Bailey Creek in September 2006. Treatments involved whole tree removal using track-laying harvesters and rubber tire skidders. More than 80% of all samples analyzed for NO₃-N, NH₄-N, and PO₄-P at Pine, Bogard, and Bailey Creeks were below the detection limit, with the exception of naturally elevated PO₄-P in Bogard Creek. All nutrient concentrations (NO₃-N, NH₄-N, PO₄-P, K, and SO₄-S) showed little variation within streams and across years. Turbidity and TSS exhibited annual variation, but there was no significant increase in the difference between upstream and downstream turbidity and TSS levels. There was a significant decrease in stream canopy cover and increase in the potential fraction of solar radiation reaching the streams in response to the Pine-Bogard Phase 3 and Bailey treatments; however, there was no corresponding increase in stream temperatures. Macroinvertebrate metrics indicated healthy aquatic ecosystem conditions throughout the course of the study. Lastly, the removal of vegetation significantly increased soil moisture in treated stands relative to untreated stands. These results indicate that, with careful planning and implementation of site-specific best management practices

  12. Aquatic ecosystem response to timber harvesting for the purpose of restoring aspen.

    Directory of Open Access Journals (Sweden)

    Bobette E Jones

    Full Text Available The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003-2010 involved two projects located in Lassen National Forest. The Pine-Bogard Project consisted of three treatments adjacent to Pine and Bogard Creeks: (i Phase 1 in January 2004, (ii Phase 2 in August 2005, and (iii Phase 3 in January 2008. The Bailey Project consisted of one treatment adjacent to Bailey Creek in September 2006. Treatments involved whole tree removal using track-laying harvesters and rubber tire skidders. More than 80% of all samples analyzed for NO₃-N, NH₄-N, and PO₄-P at Pine, Bogard, and Bailey Creeks were below the detection limit, with the exception of naturally elevated PO₄-P in Bogard Creek. All nutrient concentrations (NO₃-N, NH₄-N, PO₄-P, K, and SO₄-S showed little variation within streams and across years. Turbidity and TSS exhibited annual variation, but there was no significant increase in the difference between upstream and downstream turbidity and TSS levels. There was a significant decrease in stream canopy cover and increase in the potential fraction of solar radiation reaching the streams in response to the Pine-Bogard Phase 3 and Bailey treatments; however, there was no corresponding increase in stream temperatures. Macroinvertebrate metrics indicated healthy aquatic ecosystem conditions throughout the course of the study. Lastly, the removal of vegetation significantly increased soil moisture in treated stands relative to untreated stands. These results indicate that, with careful planning and implementation of site-specific best management

  13. Bryophyte species richness on retention aspens recovers in time but community structure does not.

    Directory of Open Access Journals (Sweden)

    Anna Oldén

    Full Text Available Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer 'lifeboats' to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L. retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 'retention aspens' on 14 differently aged retention sites with 102 'conservation aspens' on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20-30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20-30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old

  14. Usando modelos de usuario en matlab® en la interfaz de aspen plus® con excel® como puente

    OpenAIRE

    FONTALVO ALZATE, JAVIER

    2014-01-01

    El diseño de procesos intensificados y de nuevas tecnologías requiere de herramientas de simulación como Aspen Plus®. Sin embargo, las operaciones unitarias que no se incluyen en Aspen Plus pueden ser simuladas usando Matlab e integradas con la interfaz de Aspen Plus. De esta forma se pueden aprovechar todas la capacidades de Aspen plus como la optimización, el análisis de sensibilidad y la estimación de costos. Este artículo describe en detalle cómo implementar esta integración. La interfaz ...

  15. Aspen-Plus模拟在氟化工中的应用

    Institute of Scientific and Technical Information of China (English)

    谢青

    2015-01-01

    随着我国经济的快速发展,高新科技领域的不断进步,以及社会各领域间的广泛渗透交流,尤其是Aspen- Plus系统,化工领域的广泛应用,其极大的促进了化工行业生产力和生产效率的提高,为推动化工行业的健康可持续发展发挥关键作用。因Aspen- Plus系统,在生产装置优化等方面,具备优异的特性,因而当前其在化工行业的多个领域,如氟化工中得到了充分的应用,并取得了良好效果。本文将就Aspen- Plus模拟系统,当前在氟化工中应用情况进行详细分析。

  16. Drought-induced xylem pit membrane damage in aspen and balsam poplar.

    Science.gov (United States)

    Hillabrand, Rachel M; Hacke, Uwe G; Lieffers, Victor J

    2016-10-01

    Drought induces an increase in a tree's vulnerability to a loss of its hydraulic conductivity in many tree species, including two common in western Canada, trembling aspen (Populus tremuloides) and balsam poplar (Populus balsamifera). Termed 'cavitation fatigue' or 'air-seeding fatigue', the mechanism of this phenomenon is not well understood, but hypothesized to be a result of damage to xylem pit membranes. To examine the validity of this hypothesis, the effect of drought on the porosity of pit membranes in aspen and balsam poplar was investigated. Controlled drought and bench dehydration treatments were used to induce fatigue and scanning electron microscopy (SEM) was used to image pit membranes for relative porosity evaluations from air-dried samples after ethanol dehydration. A significant increase in the diameter of the largest pore was found in the drought and dehydration treatments of aspen, while an increase in the percentage of porous pit membranes was found in the dehydration treatments of both species. Additionally, the location of the largest pore per pit membrane was observed to tend toward the periphery of the membrane.

  17. Phosphate removal by refined aspen wood fiber treated with carboxymethyl cellulose and ferrous chloride.

    Science.gov (United States)

    Eberhardt, Thomas L; Min, Soo-Hong; Han, James S

    2006-12-01

    Biomass-based filtration media are of interest as an economical means to remove pollutants and nutrients found in stormwater runoff. Refined aspen wood fiber samples treated with iron salt solutions demonstrated limited capacities to remove (ortho)phosphate from test solutions. To provide additional sites for iron complex formation, and thereby impart a greater capacity for phosphate removal, a fiber pretreatment with an aqueous solution of a non-toxic anionic polymer, carboxymethyl cellulose (CMC), was evaluated. Problems with excessive viscosities during the screening of commercially available CMC products led to the selection of an ultra low viscosity CMC product that was still usable at a 4% concentration in water. Soxhlet extractions of chipped aspen wood and refined aspen wood fiber samples showed a higher extractives content for the refined material. Analysis of these extracts by FTIR spectroscopy suggested that the higher extractives content for the refined material resulted from the fragmentation of cell wall polymers (e.g., lignin, hemicelluloses) normally insoluble in their native states. Spectroscopic analysis of CMC and ferrous chloride treated fibers showed that the complex formed was sufficiently stable to resist removal during subsequent water washes. Equilibrium sorption data, which fit better with a Freundlich isotherm model than a Langmuir isotherm model, showed that phosphate removal could be enhanced by the CMC pretreatment. Results suggest that the process outlined may provide a facile means to improve the phosphate removal capacity of biomass-based stormwater filtration media.

  18. Testing Transgenic Aspen Plants with bar Gene for Herbicide Resistance under Semi-natural Conditions.

    Science.gov (United States)

    Lebedev, V G; Faskhiev, V N; Kovalenko, N P; Shestibratov, K A; Miroshnikov, A I

    2016-01-01

    Obtaining herbicide resistant plants is an important task in the genetic engineering of forest trees. Transgenic European aspen plants (Populus tremula L.) expressing the bar gene for phosphinothricin resistance have been produced using Agrobacterium tumefaciens-mediated transformation. Successful genetic transformation was confirmed by PCR analysis for thirteen lines derived from two elite genotypes. In 2014-2015, six lines were evaluated for resistance to herbicide treatment under semi-natural conditions. All selected transgenic lines were resistant to the herbicide Basta at doses equivalent to 10 l/ha (twofold normal field dosage) whereas the control plants died at 2.5 l/ha. Foliar NH4-N concentrations in transgenic plants did not change after treatment. Extremely low temperatures in the third ten-day period of October 2014 revealed differences in freeze tolerance between the lines obtained from Pt of f2 aspen genotypes. Stable expression of the bar gene after overwintering outdoors was confirmed by RT-PCR. On the basis of the tests, four transgenic aspen lines were selected. The bar gene could be used for retransformation of transgenic forest trees expressing valuable traits, such as increased productivity.

  19. EFFECT OF THERMAL TREATMENT ON THE CHEMICAL COMPOSITION AND MECHANICAL PROPERTIES OF BIRCH AND ASPEN

    Directory of Open Access Journals (Sweden)

    Duygu Kocaefe

    2008-05-01

    Full Text Available The high temperature treatment of wood is one of the alternatives to chemical treatment. During this process, the wood is heated to higher temperatures than those of conventional drying. The wood structure changes due to decomposition of hemicelluloses, ramification of lignin, and crystallization of cellulose. The wood becomes less hygroscopic. These changes improve the dimensional stability of wood, increase its resistance to micro-organisms, darken its color, and modify its hardness. However, wood also might loose some of its elasticity. Consequently, the heat treatment conditions have to be optimized. Therefore, it is important to understand the transformation of the chemical structure of wood caused by the treatment. In this study, the modification of the surface composition of the wood was followed with Fourier transform infrared spectroscopy (FTIR and inverse gas chromatography (IGC under different experimental conditions. The effect of maximum treatment temperatures on the chemical composition of Canadian birch and aspen as well as the correlations between their chemical transformation and different mechanical properties are presented. FTIR analysis results showed that the heat treatment affected the chemical composition of birch more compared to that of aspen. The results of IGC tests illustrated that the surfaces of the aspen and birch became more basic with heat treatment. The mechanical properties were affected by degradation of hemicellulose, ramification of lignin and cellulose crystallization.

  20. DECAY RESISTANCE AND PHYSICAL PROPERTIES OF OIL HEAT TREATED ASPEN WOOD

    Directory of Open Access Journals (Sweden)

    Behzad Bazyar

    2011-12-01

    Full Text Available The decay resistance of oil-heat treated aspen wood (Populus tremula l. against white rot fungi (Coriolus versicolor and brown rot fungi (Coniophora puteana was investigated. Three different temperature stages and two time levels for oil heat treatment for the selection of optimum conditions were determined. Linseed oil as a heating medium was used. The mass loss of treated samples that were exposed to both fungi was significantly lower than that of the control samples. Results also showed improvement in dimensional stability after oil heat treatment. Decay resistance and dimensional stability of aspen wood were increased significantly with temperature increasing, but time seemed to have no effect on those properties. Oil heat treatment is a suitable method to improve decay resistance of aspen wood as it reduced the mass loss by 71% and 77% against Coriolus versicolor and Coniophora puteana compared with control samples, respectively. On the other hand, oil heat treatment improved the dimensional stability by about 20.5%.

  1. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    Eric C. Xu; Yajun Zhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes.The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  2. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    EricC.Xu; YajunZhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes. The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  3. Comparing growth rate in a mixed plantation (walnut, poplar and nurse trees with different planting designs: results from an experimental plantation in northern Italy

    Directory of Open Access Journals (Sweden)

    Francesco Pelleri

    2013-12-01

    Full Text Available 800x600 Results of a mixed plantation with poplar, walnut and nurse trees established in winter 2003 in Northern Italy, are reported. Main tree species (poplar and walnut were planted according to a rectangular design (10 x 11m, with different spacings and alternate lines. The experimental trial was carried out to verify the following working hypotheses: (i possibility to combine main trees with different growth levels (common walnut, hybrid walnut, and different poplar clones and test two different poplar and walnut spacings (5.0 and 7.4 m in the same plantation; (ii opportunity to reduce cultivation’s workload, in comparison with poplar monoculture, using mixtures with different poplar clones and N-fixing nurse trees; (iii verifying the growth pattern of two new poplar clones in comparison with the traditional clones cultivated for different purposes in Italy.The use of different valuable crop trees’ mixtures intercropped with nurse trees and shrubs (including N-fixing trees allows to decrease the cultivation’s workload. In fact, a heavy reduction of cultural practices - fertilizers, weed control, irrigation and pesticides applications (-61% are the main concurrent, supplementary benefits. The best growth performances (DBH and tree height, associated with the higher competition towards walnuts, were recorded with the new clones Lena and Neva in comparison with the I214 and Villafranca. The closer spacing (5 m between poplar and walnut trees was found to be unsuited to get merchantable poplars sized 30 cm without developing a heavy competition towards walnut trees. The wider spacing (7.4 m resulted vice versa suitable to get poplar trees sized as requested by veneer factories and to maintain an acceptable competitive level with walnut. Within this plantation design, a shorter rotation (8 yrs is needed for Lena and Neva clones in comparison with I214 and Villafranca (10 yrs. Walnut intercropped with poplar showed cone-shaped crowns, light

  4. 基于ASPEN PLUS软件的甲烷化工艺模型%Simulation of methanation process based on ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    何一夫

    2012-01-01

    利用ASPEN PLUS对煤制天然气的甲烷化工艺进行了流程模拟.模型模拟得到了替代天然气成分、反应器出口温度、循环比、分流率,揭示了循环比和分流率对反应器出口温度的影响.通过该模型,能够为工艺方案比选、优化设计提供模拟和预测.%The methanation process model is proposed and simulated by ASPEN PLUS software. The substitute natural gas composition, the reactor outlet temperature, the recycle ratio and the split ratio are obtained, which suggests the main influence of recycle ratio and the split ratio on the reactor outlet temperature. The model can simulate and predict the methanation process for process comparison and optimization design.

  5. Dynamic Simulation Analysis on Steam Pipeline Net Based on ASPEN HYSYS%基于 ASPEN HYSYS对蒸汽管网动态模拟分析

    Institute of Scientific and Technical Information of China (English)

    张亮

    2015-01-01

    以大型化工项目蒸汽系统的设计为例,介绍了煤化工项目中蒸汽系统的重要性,利用ASPEN HYSYS 软件对超高压、高压和低压蒸汽管网的意外停车等工况进行动态模拟,分析当前设计的合理性,优化控制器的整定参数,为设计改进提供合理的动态数据。%Taking the design of steam system in the large-sized chemical project as an example, author has introduced the importance of steam system in the chemical project of coal, dynamic simulation has been made for working conditions of the unexpected shut-down and so on of super high pressure, high pressure and low pressure steam pipeline nets, using the ASPEN HYSYS software;author has analyzed the reasonability of present design, has opti-mized the setting parameters of the controller, so it provided the rational and dynamic data for improving the design.

  6. 基于Aspen Plus的蒸汽透平网络模拟和优化%Simulation and optimization of steam turbine network with Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    马琳瑛; 赵亮; 李泽秋; 钱锋

    2012-01-01

    According to the unreasonable phenomena in the steam piping network of ethylene plant, the steam turbine network of the device is simulated and optimized by the chemical process software, Aspen Plus. The influence of operating condition change on turbine efficiency is discussed through simulation of the turbine, such as extraction steam flow, into steam temperature, exhaust steam pressure. Based on the results, the steam turbine network is simulated and optimized by particle swarm optimization through the interface toolkit MAP, while extraction steam flow for independent variable and the total into steam flow for target variables. Using intelligent algorithm, the defect of model's not easy to converge is avoided, which is caused by setting too much constraints as Design Regulations in Aspen Plus. The optimization results show that in the condition of meeting the same output power and the requirement of the other pipe networks, the steam consumption of supper-high-pressure (SS) could be reduced effectively by selecting the extraction capacity of every turbine reasonably. The turbine network optimized could decrease 0.6 ton SS consumption per hour.%针对乙烯装置蒸汽管网用能过程中存在的不合理现象,采用Aspen Plus化工流程软件对其中的蒸汽透平网络进行了模拟和优化.通过对单个透平的模拟,分析了透平抽汽量、进汽温度和排汽压力等操作条件的变化对透平效率的影响.在此基础上模拟了蒸汽透平网络,并以透平抽汽量为自变量、透平网络总进汽量为目标变量,通过MATLAB-Aspen Plus接口工具箱使用粒子群优化算法(PSO)对其进行操作参数优化.采用智能算法,避开了因在Aspen Plus中设置过多约束作为设计规定而导致模型不易收敛的不足;对于约束条件的处理,通过对不满足约束的粒子加以惩罚来实现.优化结果表明,在满足透平输出功率以及低等级管网蒸汽用量需求的前提下,通过合理分

  7. Rejuvenated sycamore cuttings for energy plantations

    Energy Technology Data Exchange (ETDEWEB)

    Land, S.B. Jr.; Elam, W.W. [Mississippi State Univ., MS (United States). Dept. of Forestry; Khan, Mohammad [Pakistan Forest Inst., Peshawar (Pakistan). Forestry Research Div.

    1995-12-31

    Rejuvination of mature, progeny tested American sycamore trees is needed to increase rooting success of cuttings for energy plantations. Studies conducted in Mississippi (U.S.A.) indicated that hedging of stock plants and spraying the stock plants with benzyl adenine may rejuvinate the cuttings. Percentages of cuttings with early bud break in one study and with sprouts and roots after nine months in another study were increased. The rooted cuttings grew rapidly like juvenile material and showed no plagiotrophic effects during the first year after transplanting. At the end of that year the dry weight was 2.13 Mg ha{sup -1} (1.2 m x 3.6 m spacing) and was distributed in stems (31%), branches (14%), leaves (24%) and roots (31%). An IBA rooting powder decreased rooting success. Planting cuttings directly in the nursery, rather than first in the greenhouse, increased success when frost was absent. Use of cuttings of greater than 14 m diameter with a node within 2 cm of the base increased success. Clonal differences in frost susceptibility of sprouting cuttings were observed. (author)

  8. Of peasants, plantations, and immigrant proletarians

    Directory of Open Access Journals (Sweden)

    Samuel Martí­nez

    1993-01-01

    Full Text Available [First paragraph] Dominican Sugar Plantations: Production and Foreign Labor Integration. MARTIN F. MURPHY. New York: Praeger, 1991. xii + 186 pp. (Cloth US$49.95 Peasants in Distress: Poverty and Unemployment in the Dominican Republic. ROSEMARY VARGAS-LUNDIUS. Boulder CO: Westview 1991. xxi + 387 pp. (Paper US$ 32.95 Few other places in the Caribbean region have as great a potential for international conflict as the island of Hispaniola. The historical antagonism between Haiti and the Dominican Republic is no doubt known to readers of this journal, as is the recent upsurge in tension between the two countries, which culminated in the expulsion of tens of thousands of Haitian immigrants from the Dominican Republic, from June to September 1991. The quickening pace of events, added to the worsening spiral of economic hardship gripping both nations, threaten to render obsolete even the most recent analyses of relations between the two countries. Even so, against the background of an increasingly acrimonious debate between the Dominican government and international human rights organizations accusing it of enslaving Haitian immigrants in the cane flelds, the appearance of two works by long-time students of the migration of Haitians as cane workers to the Dominican Republic is particularly timely.

  9. Simulation of coal liquefaction process by developing user models on Aspen Plus platform%Aspen Plus用户模型技术的煤直接液化全流程模拟

    Institute of Scientific and Technical Information of China (English)

    单贤根; 常小瑞; 任琼; 江洪波; 翁惠新

    2014-01-01

    Based on six lumped kinetic model, this paper used the BFGS optimization algorithm to obtain kinetic constant of heating-up and isothermal stage of direct coal liquefaction process, and through regression of experimental data to get specific product composition for separation unit of direct coal liquefaction. Then the Aspen Plus user model of direct coal liquefaction was developed and integrated with the Aspen Plus software to achieve an entire process simulation of direct coal liquefaction process in Aspen Plus platform which can make the best use of its powerful databases and simulation calculation ability of separation processes. The calculation value of gas liquid equilibrium in high temperature and low temperature separators for reaction products agreed well with the experiment data. The entire process simulation in Aspen Plus platform can provide technical support for the optimization of direct coal liquefaction reaction and separation conditions.%基于六集总动力学模型,采用BFGS优化算法获得煤直接液化升温阶段和恒温阶段的反应动力学常数,同时通过试验数据回归得到用于煤直接液化分离单元的具体产品组成,并以此为基础开发了煤直接液化反应的Aspen Plus用户模型。在此基础上,将上述煤直接液化用户模型与Aspen Plus流程模拟软件集成在一起,充分利用Aspen Plus软件强大的性质数据库和分离过程模拟计算能力,最终实现了基于Aspen Plus平台的煤直接液化全流程模拟,模拟计算得到的煤直接液化反应产物在高温和低温分离器的气液相平衡数据与实验值较吻合。基于Aspen Plus的全流程模拟可以为煤直接液化反应和分离条件的优化选择提供技术参考。

  10. Applications of Aspen Plus in the Teaching of the Analysis and Synthesis for Chemical Engineering Process%Aspen plus在化工过程分析与合成课程教学中的应用

    Institute of Scientific and Technical Information of China (English)

    王磊; 李书珍; 刘卫民

    2012-01-01

    Analysis and Synthesis for Chemical Engineering Process was an important professional course for chemical majors,which was also a strong practical course.In the paper,dimethyl ether distillation column of the actual process of methanol to dimethyl ether was simulated and analyzed by Aspen Plus software.Students were familiarized with the use of Aspen Plus software in the process of simulation and analysis.In addition,the application of aspen Plus could help the following teaching of Chemical Process design.%化工过程分析与合成是化工类实践性非常强的专业基础课,精馏塔的实践教学是教学的重点和难点。文章采用Aspen Plus软件,以甲醇制二甲醚的实际工艺为案例,对二甲醚精馏塔进行模拟、分析,同时使学生熟悉Aspen Plus软件的使用,为后续化工设计打下基础。

  11. Leaf size serves as a proxy for xylem vulnerability to cavitation in plantation trees.

    Science.gov (United States)

    Schreiber, Stefan G; Hacke, Uwe G; Chamberland, Sabrina; Lowe, Christopher W; Kamelchuk, David; Bräutigam, Katharina; Campbell, Malcolm M; Thomas, Barb R

    2016-02-01

    Hybrid poplars are an important renewable forest resource known for their high productivity. At the same time, they are highly vulnerable to water stress. Identifying traits that can serve as indicators for growth performance remains an important task, particularly under field conditions. Understanding which trait combinations translate to improved productivity is key in order to satisfy the demand for poplar wood in an uncertain future climate. In this study, we compared hydraulic and leaf traits among five hybrid poplar clones at 10 plantations in central Alberta. We also assessed the variation of these traits between 2- to 3-year-old branches from the lower to mid-crown and current-year long shoots from the mid to upper crown. Our results showed that (1) hybrid poplars differed in key hydraulic parameters between branch type, (2) variation of hydraulic traits among clones was relatively large for some clones and less for others, and (3) strong relationships between measured hydraulic traits, such as vessel diameter, cavitation resistance, xylem-specific and leaf-specific conductivity and leaf area, were observed. Our results suggest that leaf size could serve as an additional screening tool when selecting for drought-tolerant genotypes in forest management and tree improvement programmes.

  12. Is spatial structure the key to promote plant diversity in Mediterranean forets plantations?

    NARCIS (Netherlands)

    González-Moreno, P.; Quero, J.L.; Poorter, L.; Bonet, F.J.; Zamora, R.

    2011-01-01

    Mediterranean forest plantations are currently under an intense debate related to their ecological function, sustainability and future performance. In several Mediterranean countries, efforts are directed to convert pine plantations into mixed and more diverse forests. This research aims to evaluate

  13. Is spatial structure the key to promote plant diversity in Mediterranean forets plantations?

    NARCIS (Netherlands)

    González-Moreno, P.; Quero, J.L.; Poorter, L.; Bonet, F.J.; Zamora, R.

    2011-01-01

    Mediterranean forest plantations are currently under an intense debate related to their ecological function, sustainability and future performance. In several Mediterranean countries, efforts are directed to convert pine plantations into mixed and more diverse forests. This research aims to evaluate

  14. Fire effects in Pinus uncinata Ram plantations

    Energy Technology Data Exchange (ETDEWEB)

    Cardil Forradellas, A.; Molina Terrén, D.M.; Oliveres, J.; Castellnou, M.

    2016-07-01

    Aim of study: Understanding fire ecology of main forest species is essential for a sound, scientifically based on managing of wildlands and also to assess likely implications due to changes in fire regime under a global change scenario. Few references can be found about fire ecology of Pinus uncinata Ram. (PU). PU species grows in the Central Pyrenees where large, severe wildland fires did not occur frequently in the past. However, several fires with extreme fire behavior have affected PU stands in last years and they might disturb other PU forest in the future. Area of study: Cabdella fire (February 2012), in Lleida province, is one of the several wildland fires occurred in 2012 (winter season) in the Central Pyrenees. Fire affected a large PU plantation (102 ha) located at 1.800-2,100 meters above the sea. Material and methods: We have analyzed first order fire effects in three fireline intensity thresholds along three years in terms of mortality ratio, scorched height, percentage of scorched crown volume and bark char height. Main results: PU seems to be a very tolerant species to low and medium fire line intensity but fire effects were very significant when fire line intensity was high. In medium fireline intensity sites, probability of mortality ranged from 15 to 30% and the dead trees had the highest values on scorched height and percentage of scorched crown volume. Research highlights: Results from this work supports that prescribed burning might be used to efficiently decrease fuel load and fuel vertical continuity while avoiding considerable PU mortality. It also displayed that when fuel management has been implemented, PU mortality might be limited even under extreme fire behavior. (Author)

  15. Fire effects in Pinus uncinata Ram plantations

    Directory of Open Access Journals (Sweden)

    Adrián Cardil Forradellas

    2016-04-01

    Full Text Available Aim of study: Understanding fire ecology of main forest species is essential for a sound, scientifically based on managing of wildlands and also to assess likely implications due to changes in fire regime under a global change scenario. Few references can be found about fire ecology of Pinus uncinata Ram. (PU. PU species grows in the Central Pyrenees where large, severe wildland fires did not occur frequently in the past. However, several fires with extreme fire behavior have affected PU stands in last years and they might disturb other PU forest in the future.Area of study: Cabdella fire (February 2012, in Lleida province, is one of the several wildland fires occurred in 2012 (winter season in the Central Pyrenees. Fire affected a large PU plantation (102 ha located at 1.800-2,100 meters above the sea.Material and methods: We have analyzed first order fire effects in three fireline intensity thresholds along three years in terms of mortality ratio, scorched height, percentage of scorched crown volume and bark char height.Main results: PU seems to be a very tolerant species to low and medium fire line intensity but fire effects were very significant when fire line intensity was high. In medium fireline intensity sites, probability of mortality ranged from 15 to 30% and the dead trees had the highest values on scorched height and percentage of scorched crown volume.Research highlights: Results from this work supports that prescribed burning might be used to efficiently decrease fuel load and fuel vertical continuity while avoiding considerable PU mortality. It also displayed that when fuel management has been implemented, PU mortality might be limited even under extreme fire behavior.Abbreviations used: PU: Pinus uncinata Ram.

  16. Modeling Pine Plantation NEP Using Landsat

    Science.gov (United States)

    Wynne, R. H.; Potter, C. S.; Blinn, C. E.

    2008-12-01

    The CASA (Carnegie Ames Stanford Approach) ecosystem process model predicts terrestrial ecosystem fluxes using satellite-based inputs at a maximum geographic resolution of 30 meters to infer variability in forest carbon fluxes. We are using CASA to model pine plantation net ecosystem production (NEP) under a range of standard silvicultural prescriptions, primarily thinning by fertilization interactions. Landsat scenes from WRS path/row 14/35, 21/37, and 16/34 are being used. Within each frame, all available cloud-free scenes within a two- to three-year period have been obtained from the USGS EROS Data Center processed to L1T, and subsequently converted to top-of-atmosphere reflectance using standard methods and the latest calibration parameter files. Atmospheric amelioration started with dark object subtraction (band minimum) and only proceeded to more complex techniques as necessary. Subsequent to preprocessing, the reduced simple ratio (RSR; using global min/max) was calculated for all images for each WRS path/row. Pure pine pixels in each frame were identified using unsupervised classification of the most recent leaf-off scene. We developed four age classes using two decades of Landsat data over each WRS path/row. CASA runs, which require soil parameters, and gridded climate/solar radiation in addition to satellite-derived vegetation indices, are now complete. Soil respiration and productivity estimates are being evaluated using a regionwide network of validation sites spanning the range of loblolly pine (Texas to Virginia). Preliminary results indicate that Landsat-based process modeling (1) is necessary for the scale at which land is actually managed and (2) produces estimates with an accuracy and precision affording improved understanding and management of forest ecosystems.

  17. Study on Cultivation Nutrition of Cunninghamia lanceolata Plantations with Multi-generation Management

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on the previous study on cultivation nutrition of Cunninghamia lanceolata plantations of first generation, the cultivation nutrition of C. lanceolata plantations with multi-generation was studied. The results show that there are significant differences in the growth, development and nutrient assimilation among C. lanceolata plantations with different generations and nutrition conditions. These differences are closely related to the land fertility decline of C. lanceolata plantations. This paper de...

  18. Aspen Plus与Visual C++混合编程在化工模拟中的应用%Application of Mixed Programming Based on Aspen Plus and Visual C++ in Chemical Simulation

    Institute of Scientific and Technical Information of China (English)

    蔡振兴

    2014-01-01

    化工过程模拟软件Aspen Plus在化工流程的设计、校核方面得到了广泛的应用,显著提高了化工工艺流程设计、校核的效率和水平.Aspen Plus支持ActiveX自动控制技术,并符合CAPE-OPEN接口标准.借助Visual C++编程环境,实现了对Aspen Plus数据库的调用、单元模块的开发、以及与水力学软件的集成.

  19. The expansion of farm-based plantation forestry in Vietnam.

    Science.gov (United States)

    Sandewall, Mats; Ohlsson, Bo; Sandewall, R Kajsa; Viet, Le Sy

    2010-12-01

    This study targets plantation forestry by farm households (small holders), which is increasing globally and most rapidly in China and Vietnam. By use of an interdisciplinary approach on three study sites in Vietnam, we examined the trends in farmers' tree planting over time, the various pre-requisites for farm-based plantation forestry and its impact on rural people's livelihood strategies, socioeconomic status, income and security. The findings indicated a change from subsistence to cash-based household economy, diversification of farmers' incomes and a transformation of the landscape from mainly natural forests, via deforestation and shifting cultivation, to a landscape dominated by farm-based plantations. The trend of transformation, over a period of some 30 years, towards cash crops and forestry was induced by a combination of policy, market, institutional, infrastructural and other conditions and the existence of professional farming communities, and was most rapid close to the industrial market.

  20. Carbon Sequestration in loblolly pine plantations: Methods, limitations, and research needs for estimating storage pools

    Science.gov (United States)

    Kurt Johnsen; Bob Teskey; Lisa Samuelson; John Butnor; David Sampson; Felipe Sanchez; Chris Maier; Steve McKeand

    2004-01-01

    Globally, the species most widely used for plantation forestry is loblolly pine (Pinus taeda L.). Because loblolly pine plantations are so extensive and grow so rapidly, they provide a great potential for sequestering atmospheric carbon (C). Because loblolly pine plantations are relatively simple ecosystems and because such a great volume of...

  1. Demarcation of Seabuckthorn Plantations in Three Northern Areas of China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Seabuckthorn (Hippophae rhamnoides) planting areas in the three northern areas (north, northeast and northwest) of China are divided into five planting zones: the semi-humid forest prairie climate zone for ecological and economic types of seabuckthorn plantations in the southern part of the Loess Plateau; the semi-arid steppe climate zone for similar types of plantations in the central part of the Loess Plateau; the arid desert steppe climate zone for ecological type of seabuckthorn plantations in the northern part of the Loess Plateau; the semi-arid and semi-humid steppe climate zone again for ecological and economic types of plantations in northern Hebei and western Liaoning and the cold humid steppe climate zone for economic types of plantations in the northern part of northeast China. The aim of this demarcation is to avoid a random introduction of seabuckthorn. In each of the five zones,objectives should be set and suitable seabuckthorn species, subspecies and varieties should be planted according to site conditions,seed sources and methods of tree breeding. The cultivation centers, bases, stations, or units should be established and successful models of seedling and planting methods should be encouraged. The principle of matching trees with suitable site conditions and adjusting measures to local conditions should be practiced. From a strategic viewpoint of solving ecological and economic problems of seabuckthorn development in the three northern areas, every seabuckthorn center must have its own germplasm nursery, standard plantation for popularizing, excellent seed and seedling nurseries and sufficient afforestation areas for demonstration and propaganda purposes. These measures would improve the ecological environment and promote economic and social development in the three northern areas of China.

  2. The Application of Aspen Plus in the Design of Distillation Column%流程模拟软件Aspen Plus在精馏塔设计中的应用

    Institute of Scientific and Technical Information of China (English)

    李峰; 赵新堂; 万宝锋

    2014-01-01

    The simple design and rigorous accounting on the distillation column has been performed by Aspen Plus in this paper. Also, the analysis of the influence factors on the design of distillation column was completed. In addition, the economic accounting of distillation column was discussed preliminarily.%以Aspen Plus流程模拟软件对精馏塔进行了简捷设计和严格核算,对精馏塔设计的影响因素进行了分析,并对精馏塔的经济核算进行了初步说明。

  3. 运用ASPEN B-JAC 设计管壳式换热器%Design and Optimize Tube/Shell Heat Exchanger by Aspen B-jac

    Institute of Scientific and Technical Information of China (English)

    周奇

    2010-01-01

    描述了运用ASPEN B-JAC换热器计算软件进行管壳式换热器设计的步骤,讨论了换热器管程壳程优化设计的要点以及利用ASPEN B-JAC进行换热器设计优化过程中应注意的问题,为管壳式换热器的优化设计提供了参考.

  4. Aspen Plus在化工设计物料衡算中的应用分析

    Institute of Scientific and Technical Information of China (English)

    茅慧

    2015-01-01

    化工领域中最关键的基础内容就是化工设计,随着社会的进步和科学技术的发展,传统的化工设计方式逐渐被Aspen Plus软件所替代,在化工设计领域中发挥着重要作用.本文主要阐述了Aspen Plus的概念,并对其在化工设计发挥的作用进行探究,分析了Aspen Plus在化工设计物料衡算中的应用,以期更加透彻的分析化工过程连续生产时的物料衡算,进一步提高化工设计效果.

  5. The effects of energy grass plantations on biodiversity

    Energy Technology Data Exchange (ETDEWEB)

    Semere, T.; Slater, F.

    2005-07-01

    The ecological impact on local wildlife of biomass plantations of three different species of grasses has been monitored in the years 2002 to 2004 inclusive at farms in Herefordshire UK. Two of the grasses were not native to Britain. Wildlife monitored included ground flora, beetles, insects, birds, small mammals, butterflies, bees and hoverflies. The results provide a baseline of biodiversity data from biomass farms in England, although due to poor crop growth, the data from the switch-grass plantation was incomplete. The surveys were carried out by Cardiff University supported financially by the DTI.

  6. Aspen height, stem-girth and survivorship in an area of high ungulate use

    Science.gov (United States)

    Keigley, R.B.; Frisina, M.R.

    2008-01-01

    An increase in ungulate population size potentially exposes aspen suckers, saplings, and trees to increased use. This study examined how stem height and girth influenced the selection of stems by ungulates for browsing, rubbing, and gnawing, and reconstructed the history of ungulate use for the study area. Transects were run through each of three aspen clones growing in southwestern Montana to determine height, circumference, and the surface area from which bark was totally and partially removed by rubbing and gnawing. Stems 20-250 cm tall were browsed. Stems 2-13 cm diameter were preferentially selected for rubbing and gnawing. The area of totally removed bark on dead saplings was twice the area of removed bark on live stems of similar diameter, suggesting that bark removal played a major role in the death of some stems. Based on an analysis of stem height and age, ungulate browsing was inferred to have increased from a light-to-moderate level to an intense level in 1991. The depth of scars was used to date scarring events. An increase in rubbing and gnawing was determined to have occurred about 1985. We concluded that elk were primarily responsible for the observed impacts. The combined effect of rubbing, gnawing, and browsing affects a broader span of ages compared to the effect of browsing alone. If prescribed fire is used to rejuvenate aspen stands, the resulting young stems should be protected from heavy browsing, rubbing and gnawing until they reach about 13 cm diameter and have grown out of the browse zone.

  7. Mercury in Red Aspen Boletes (Leccinum aurantiacum) mushrooms and the soils.

    Science.gov (United States)

    Falandysz, Jerzy; Kowalewska, Izabela; Nnorom, Innocent C; Drewnowska, Małgorzata; Jarzyńska, Grażyna

    2012-01-01

    This communication reports data on the mercury contents of Red Aspen Boletes (Leccinum aurantiacum) mushrooms and the forest soils substrate layer (0-10 cm) underneath the fruit bodies collected from nine spatially distant sites across Poland. Total Hg concentration in soil substrate in seven of the nine sites studied varied from 0.0078 ± 0.0012 to 0.028 ± 0.007 μg/g dry weight (dw) and this could be considered baseline concentrations for uncontaminated forest soils in Poland. The arithmetic mean of mercury in Red Aspen Bolete caps varied, depending on the site from 0.27 ± 0.07 to 1.3 ± 0.6 μg/g dw. The lowest Hg contents in soil (0.011 ± 0.006 μg/g and 0.009 ± 0.002 μg/g) were observed for the sites of Wandalin and Opole Lubelskie (from Lubelska Upland region) with the corresponding highest bioconcentration factor (BCF) values of 130 ± 66 and 110 ± 13 for the mushroom caps and 58 ± 29 and 64 ± 8 for the stipes, respectively. The BCF values in caps showed a downward trend with increasing mercury content of soil. A meal of 300 g of fresh caps of Red Aspen Bolete from Aleksandrów Kujawski region could expose a consumer to 8.1 μg Hg, while this will be 39 μg at the Lubelska Upland amounting to 39 and 186 % of daily Hg reference dose, respectively.

  8. Heterozygosity, gender, and the growth-defense trade-off in quaking aspen.

    Science.gov (United States)

    Cole, Christopher T; Stevens, Michael T; Anderson, Jon E; Lindroth, Richard L

    2016-06-01

    Although plant growth is generally recognized to be influenced by allocation to defense, genetic background (e.g., inbreeding), and gender, rarely have those factors been addressed collectively. In quaking aspen (Populus tremuloides Michx.), phenolic glycosides (PGs) and condensed tannins (CTs) constitute up to 30 % of leaf dry weight. To quantify the allocation cost of this chemical defense, we measured growth, defense chemistry, and individual heterozygosity (H obs at 16 microsatellite loci) for male and female trees in both controlled and natural environments. The controlled environment consisted of 12 juvenile genets grown for 3 years in a common garden, with replication. The natural environment consisted of 51 mature genets in wild populations, from which we sampled multiple ramets (trees) per genet. Concentrations of PGs and CTs were negatively correlated. PGs were uncorrelated with growth, but CT production represented a major cost. Across the range of CT levels found in wild-grown trees, growth rates varied by 2.6-fold, such that a 10 % increase in CT concentration occurred with a 38.5 % decrease in growth. H obs had a marked effect on aspen growth: for wild trees, a 10 % increase in H obs corresponded to a 12.5 % increase in growth. In wild trees, this CT effect was significant only in females, in which reproduction seems to exacerbate the cost of defense, while the H obs effect was significant only in males. Despite the lower growth rate of low-H obs trees, their higher CT levels may improve survival, which could account for the deficit of heterozygotes repeatedly found in natural aspen populations.

  9. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    Science.gov (United States)

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.

  10. Detection of Aspens Using High Resolution Aerial Laser Scanning Data and Digital Aerial Images

    Directory of Open Access Journals (Sweden)

    Kalle Eerikäinen

    2008-08-01

    Full Text Available The aim was to use high resolution Aerial Laser Scanning (ALS data and aerial images to detect European aspen (Populus tremula L. from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM was interpolated from the ALS data with a pulse density of 3.86/m2, low-pass filtered using Height-Based Filtering (HBF and binarized to create the mask needed to separate the ground pixels from the canopy pixels within individual areas. Watershed segmentation was applied to the low-pass filtered CHM in order to create preliminary canopy segments, from which the non-canopy elements were extracted to obtain the final canopy segmentation, i.e. the ground mask was analysed against the canopy mask. A manual classification of aerial images was employed to separate the canopy segments of deciduous trees from those of coniferous trees. Finally, linear discriminant analysis was applied to the correctly classified canopy segments of deciduous trees to classify them into segments belonging to aspen and those belonging to other deciduous trees. The independent variables used in the classification were obtained from the first pulse ALS point data. The accuracy of discrimination between aspen and other deciduous trees was 78.6%. The independent variables in the classification function were the proportion of vegetation hits, the standard deviation of in pulse heights, accumulated intensity at the 90th percentile and the proportion of laser points reflected at the 60th height percentile. The accuracy of classification corresponded to the validation results of earlier ALS-based studies on the classification of individual deciduous trees to tree species.

  11. 关于Aspen Plus在化工设计中应用的探讨

    Institute of Scientific and Technical Information of China (English)

    耿晓云[1; 李彦菊[2

    2015-01-01

    在化工设计中,Aspen Plus 是针对化工为代表的功能强大的过程系统模拟软件。介绍了如何将其引入化工设计环节。使用软件模拟可以节省计算量、提高效率,培养设计工作者解决工程问题的能力,与手工计算的差异对比分析原因。

  12. ASPEN PLUS与化工专业核心课程体系建设

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      通过分析化工专业课程体系,在传统教学的基础上,探讨将 Aspen Plus 流程模拟软件有目的、有步骤地引入化工专业核心课程化工原理、化学反应工程、化工热力学和分离工程的教学中,强化化工专业核心课程体系的建设。

  13. 关于Aspen Plus在化工设计中应用的探讨

    Institute of Scientific and Technical Information of China (English)

    耿晓云; 李彦菊

    2015-01-01

    在化工设计中,Aspen Plus 是针对化工为代表的功能强大的过程系统模拟软件,本文介绍了如何将其引入化工设计环节。使用软件模拟可以节省计算量、提高效率,培养设计工作者解决工程问题的能力,与手工计算的差异对比分析原因。

  14. 偏氟乙烯精馏的Aspen Plus模拟分析

    Institute of Scientific and Technical Information of China (English)

    钟益堂

    2014-01-01

    通过Aspen Plus模拟软件对偏氟乙烯精馏过程进行了模拟.对精馏塔的进料位置、回流比、馏出比进行了灵敏度分析,综合考虑得出精馏塔适宜进料位置NF、回流摩尔比R、馏出摩尔比D/F分别是32、0.12、0.89.模拟结果与实际生产值基本一致,可指导工业生产.

  15. ASPEN PLUS优化甲醇水分离塔操作

    Institute of Scientific and Technical Information of China (English)

    姬加良

    2010-01-01

    应用ASPEN PLUS工程软件对低温甲醇洗装置的甲醇水分离塔进行模拟,并与设计工艺包进行对比。对塔顶回流甲醇在不同含水量下的工况进行优化,将优化数据与该塔实际运行结果进行比较,为生产操作提供数据指导。

  16. 甲醇合成过程的Aspen模拟%Aspen Analog of Methanol Synthesis Process

    Institute of Scientific and Technical Information of China (English)

    孟庆军

    2005-01-01

    通过Aspen-Plus工具,采用合成动力学方程对甲醇合成流程进行了全流程模拟,分析了模拟计算结果.从循环气量、合成压力、冷却水温、合成塔进口温度、合成塔结构、催化剂装填量等方面论述了操作条件和反应器尺寸的变化对合成回路的影响.

  17. Nanocrystalline cellulose from aspen kraft pulp and its application in deinked pulp.

    Science.gov (United States)

    Xu, Qinghua; Gao, Yang; Qin, Menghua; Wu, Kaili; Fu, Yingjuan; Zhao, Jian

    2013-09-01

    Nanocrystalline cellulose (NCC) isolated from bleached aspen kraft pulp was characterized, and its application as pulp strengthening additive and retention aid was investigated. Results showed that NCC with high crystallinity of more than 80% can be obtained using 64 wt% sulfuric acid. The structure of nanocrystalline cellulose is parallelepiped rod-like, and their cross-sectional dimension is in the nanometer range with a high aspect ratio. The formation of microparticle retention systems during the application of NCC together with cationic polyacrylamide and cationic starch in deinked pulp was able to further improve pulp retention and strength properties without negative influence on the drainage.

  18. A simulation study of Solid Oxide fuel cell for IGCC power generation using Aspen Plus

    DEFF Research Database (Denmark)

    Rudra, Souman; Kim, Hyung Taek

    2010-01-01

    in a more accurate fuel cell model giving an advantage over previous system studies based on simplified SOFC models. The objective of this work is to develop a simulation model of a SOFC for IGFC system, flexible enough for use in future development, capable of predicting system performance under various...... operating conditions and using diverse fuels. The SOFC stack model developed using the chemical process flow sheet simulator Aspen Plus which is of equilibrium type and is based on Gibbs free energy minimization. The SOFC model performs heat and mass balances and considers the ohmic, activation...

  19. 采用Aspen Plus设计计算蒸汽减温减压系统

    Institute of Scientific and Technical Information of China (English)

    王潇; 刘明; 夏红勋

    2015-01-01

    采用Aspen Plus设计计算蒸汽减温减压系统,并将所得数据与现场实际装置的运行情况相比较。结果表明,采用Aspen Plus模拟计算的结果与生产装置的运行参数和物性手册的数据相一致,在工程允许误差范围之内。

  20. A study of polymerization of aspen (Populus) wood lipophilic extractives by SEC and Py-GC/MS

    CSIR Research Space (South Africa)

    Sithole, Bruce

    2013-03-01

    Full Text Available -4) in the bleach plant (5) and on paper machines (6). Consequently, considerable efforts are expended to minimize the amount of residual lipophilic extractives in aspen pulp (2,3,5,7-10) . They can include wood or chip seasoning, good barking practices... was alluded to but not studied. The objective of our work was to determine whether or not the current wood procurement practices in an aspen bleached kraft pulp mill, which include a year of seasoning as roundwood and about three weeks as chips, give...

  1. Flux agreement above a Scots pine plantation

    Science.gov (United States)

    Gay, L. W.; Vogt, R.; Bernhofer, Ch.; Blanford, J. H.

    1996-03-01

    The surface energy exchange of 12m high Scots pine plantation at Hartheim, Germany, was measured with a variety of methods during a 11-day period of fine weather in mid-May 1992. Net radiation and rate of thermal storage were measured with conventional net radiometers, soil heat flux discs and temperature-based storage models. The turbulent fluxes discussed in this report were obtained with an interchanging Bowen ratio energy budget system (BREB, at 14 m), two one-propeller eddy correlation systems (OPEC systems 1 and 2 at 17m), a 1-dimensional sonic eddy correlation system (SEC system 3) at 15 m, all on one “low” tower, and a 3-dimensional sonic eddy correlation system (SEC system 22) at 22 m on the “high” tower that was about 46 m distant. All systems measured sensible and latent heat (H and LE) directly, except for OPEC systems 1 and 2 which estimated LE as a residual term in the surface energy balance. Closure of turbulent fluxes from the two SEC systems was around 80% for daytime and 30% for night, with closure of 1-dimensional SEC system 3 exceeding that of 3-dimensional SEC system 22. The night measurements of turbulent fluxes contained considerable uncertainty, especially with the BREB system where measured gradients often yielded erroneous fluxes due to problems inherent in the method (i.e., computational instability as Bowen's ratio approaches -1). Also, both eddy correlation system designs (OPEC and SEC) appeared to underestimate |H| during stable conditions at night. In addition, both sonic systems (1- and 3-dimensional) underestimated |LE| during stable conditions. The underestimate of |H| at night generated residual estimates of OPEC LE containing a “phantom dew” error that erroneously decreased daily LE totals by about 10 percent. These special night problems are circumvented here by comparing results for daytime periods only, rather than for full days. To summarize, turbulent fluxes on the low tower from OPEC system 2 and the adjacent

  2. Using ecological memory as an indicator to monitor the ecological restoration of four forest plantations in subtropical China

    Science.gov (United States)

    Zhongyu Sun; Hai Ren; Val Schaefer; Qinfeng Guo; Jun Wang

    2014-01-01

    A large area of plantations has been established worldwide and especially in China. Evaluating the restoration status of these plantations is essential for their longterm management. Based on our previous work, we used an ecological memory (EM) approach to evaluate four 26-year-old plantations that represent four common kinds of plantations in subtropical China, i.e.,...

  3. Carbon and water vapor balance in a subtropical pine plantation

    Directory of Open Access Journals (Sweden)

    Posse G

    2016-10-01

    Full Text Available Afforestation has been proposed as an effective tool for protecting primary and/or secondary forests and for mitigating atmospheric CO2. However, the dynamics of primary productivity differs between plantations and natural forests. The objective of this work was to evaluate the potential for carbon storage of a commercial pine plantation by determining its carbon balance. Measurements started when trees were aged 6 and ended when they were older than 8 years. We measured CO2 and water vapor concentrations using the Eddy covariance method. Gross primary productivity in 2010 and 2011 was 4290 ± 473 g C m-2 and 4015 ± 485 g C m-2, respectively. Ecosystem respiration ranged between 7 and 20 g C m-2 d-1, reaching peaks in all Februaries. Of the 30 months monitored, the plantation acted as carbon source for 21 months and as carbon sink for 6 months, while values close to neutrality were obtained during 3 months. The positive balance representing CO2 loss by the system was most likely due to the cut branches left on the ground following pruning activities. The plantation was subjected to pruning in January and September 2008 and to sanitary pruning in October 2010. In all cases, cut branches were not removed but remained on the ground. Residue management seems to have a very important impact on carbon balance.

  4. Herbaceous weed control in loblolly pine plantations using flazasulfuron

    Science.gov (United States)

    Andrew W. Ezell; Jimmie L. Yeiser

    2015-01-01

    A total of 13 treatments were applied at four sites (two in Mississippi and two in Texas) to evaluate the efficacy of flazasulfuron applied alone or in mixtures for providing control of herbaceous weeds. All sites were newly established loblolly pine (Pinus taeda L.) plantations. Plots were evaluated monthly until 180 days after treatment. No phytotoxicity on pine...

  5. The Old Orchard white pine plantation at Biltmore

    Science.gov (United States)

    W. Henry McNab; Brian A. Ritter

    2000-01-01

    A pioneering case study in the Old Orchard Plantation on Biltmore Estate near Asheville, North Carolina, considered current yields and the effects of periodic thinning on height and basal area growth, as well as cubic volume and board-foot yields. Established in 1899, one of three plots of this eastern white pine stand was first thinned in 1916. Beyond providing growth...

  6. Simulation of hydrology of short rotation hardwood plantations

    Science.gov (United States)

    John E. Parsons; Carl C. Trettin

    2001-01-01

    A 76 ha hardwood plantation at Trice Research Forest near Sumter, SC is being usedto study forest hydrology on an operational scale. The overall objective of this project is to develop tools to enable forest managers to assess and manage sustainable short rotation woody crop production systems. This paper reports on the use of the water management model, WATRCOM, as a...

  7. Site Management and Productivity in Tropical Forest Plantations

    Science.gov (United States)

    A. Tiarks; E.K.S. Nambiar; C. Cossalter

    1998-01-01

    Tropical countries are expanding plantation forestry to develop sustainable woodproduction systems. Much of this is based on short rotations of exotic species. These systems require large capital investments, represent intensive land use and increase the demands on the soil. To develop options for maintaining or increasing productivity a partner-project was initiated...

  8. Individual Tree Biomass Models for Plantation Grown American Sycamore

    Science.gov (United States)

    Regan B. Willson; Bryce E. Schlaegel; Harvey E. Kennedy

    1982-01-01

    Individual tree volume and green and dry weight equations are derived for American sycamore from a 5-year-old plantation in southeast Arkansas. Two trees have been destructively sampled each year from each of 20 plots. Observations from 168 trees are used to predict tree weight and volume as a function of dbh, total height, age, and initial number of trees. Separate...

  9. Deriving Biomass Estimation Equations for Seven Plantation Hardwood Species

    Science.gov (United States)

    Bryce E. Schlaegel; Harvey E. Kennedy

    1986-01-01

    Trees of seven species sampled from a plantation over 7 years were used to derive weight equations to predict primary tree components. The seven species required the use of five different model forms to insure the greatest precision. Regardless of model form, all equations include variables for tree diameter, tree height, age, and number of trees planted. The most...

  10. Family Differences Influence the Aboveground Biomass of Loblolly Pine Plantations

    Science.gov (United States)

    P.E. Pope; D.L. Graney

    1979-01-01

    We compared the aboveground biomass of 4 half-sib families of loblolly pine (Pinus taeda L.) 11 years after planting. Total dry weights differed significantly among families in plantations on the same soil type with the same site index. Differences in biomass resulted from differences in stem form and branch size. Distribution of growth -the proportion of tree weight...

  11. Pesticide contamination of the Dridji Cotton Plantation area in the ...

    African Journals Online (AJOL)

    Pesticide contamination of the Dridji Cotton Plantation area in the Republic of Bénin. ... and vegetables eventually may not only end up on the crops, but also in soil and surface water. ... Key words: Pesticides, agriculture, humans, risk, food ...

  12. Short Communication. Restoring monoculture plantation using stand spatial structure analysis

    Directory of Open Access Journals (Sweden)

    G. Gao

    2013-03-01

    Full Text Available Aim of study. To improve the quality of monoculture plantations in China.Area of study. structure-based forest management was conducted in Rocky Mountain Area of Northern China.Material and Methods. Stand spatial structure indicators of mingling degree, uniform angle index, neighborhood comparison and opening degree were comparably investigated to understand the changes of Pinus tabulaeformis plantations.Main results. The results indicated that structure-based forest management accounted for 0.403 and 0.448 of the significant variations in mingling degree and opening degree increments, and had no essential changes in uniform angle index and neighborhood comparison. Structure-based forest management is greatly beneficial to plantation quality, and it can be a source of improvement on stand structure.Research highlights. This improved information is essential to provide a firm basis for future policy-making on how best to restore degraded forests in China as well as the rest of the world.Key words: monoculture plantation; structure-based forest management; stand spatial structure; forest restoration

  13. AVIAN RESOURCE USE IN DOMINICAN SHADE COFFEE PLANTATIONS

    Science.gov (United States)

    JOSEPH M. WUNDERLE. JR; STEVEN C. LATTAA

    1998-01-01

    We quantified foraging behavior of 19 bird species in shade coffee plantations in the Dominican Republic to document and evaluate their use of food resources in the shade overstory relative to the coffee understory. All species were observed foraging in the Znga “era overstory, and 18 of the 19 species had median foraging heights significantly above the median maximum...

  14. Plantation Patriarchy and Structural Violence: Women Workers in Sri Lanka

    NARCIS (Netherlands)

    R. Kurian (Rachel); K. Jayawardena (Kumari)

    2013-01-01

    markdownabstract__Abstract__ Plantation production began in Sri Lanka in the early 19th century under British colonial rule, when the government provided financial incentives and infrastructural support for the commercialisation and export of agricultural crops in line with promoting laissez-faire

  15. Agroecological practices in oil palm plantations: examples from the field

    Directory of Open Access Journals (Sweden)

    Bessou Cécile

    2017-05-01

    Full Text Available Palm oil is nowadays the first vegetable oil consumed worldwide. Given the world population growth and the increasing demand in fat for food and fuel, the increase in oil palm production is expected to continue. It is thus important to find ways of reducing the ecological impact of oil palm plantations at both the agroecosystem and the mill supply area levels, by improving agricultural practices and land uses. This is where agroecology can play a very critical role. The present article gathers short stories on agroecological practices currently taking place in oil palm plantations in South-East Asia. Such stories notably highlight the importance of the various palm co-products and how appropriate recycling strategies can allow for reducing external inputs to both the field and the mill. Besides limiting environmental impacts thanks to such savings, several co-products used as organic amendments can even help to maintain or enhance soil quality. Other stories explored agroecological practices developed for biological controls. Although integrated pest management has been applied in palm plantations for a long time, the underlying mechanisms are still not fully deciphered and practices still need to be improved. More knowledge is needed in order to better account for the holistic role of biodiversity and arbitrate trade-offs between practices and ecosystem services, at both plantation and landscape levels.

  16. Financial performance of loblolly and longleaf pine plantations

    Science.gov (United States)

    Steven D. Mills; Charles T. Stiff

    2013-01-01

    The financial performance of selected management regimes for loblolly (Pinus taeda L.) and longleaf pine (P. palustris Mill.) plantations were compared for four cases, each with low- and high-site productivity levels and each evaluated using 5 and 7 percent real discount rates. In all cases, longleaf pine was considered both with...

  17. Yield models for commercial willow biomass plantations in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Mola-Yudego, Blas [Faculty of Forestry, University of Joensuu, P.O. Box 111, FI-801 01 Joensuu (Finland); Aronsson, Paer [Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7016, S-750 07 Uppsala (Sweden)

    2008-09-15

    A yield model for willow plantations for bioenergy production in Sweden was developed based on recorded production of 2082 commercial plantations during the period 1989-2005. The model predicts yield for the first, second and third harvest using oats (avena) production as agro-climatic index. The mean annual yields were 2.6, 4.2 and 4.5 oven dry tonnes (odt) per hectare during the first, second and third cutting cycles, respectively. The yield correlated inversely with the length of the cutting cycle. The results of the study show significant differences between growers, which suggest the importance of proper management in the establishment and tending of the plantations. Model estimates for 25% of the best growers vary from 4.0 to 6.3 odt ha{sup -1} yr{sup -1} in 5-year-rotation plantations during the first cutting cycle, and from 5.4 to 7.1 odt ha{sup -1} yr{sup -1} in 4-year-rotations for the second cutting cycle. The proposed model can be applied in policy making and for management planning. (author)

  18. The Carbon Sequestration Potential of Tree Crop Plantations

    DEFF Research Database (Denmark)

    Kongsager, Rico; Napier, Jonas; Mertz, Ole

    2013-01-01

    ), oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and orange (Citrus sinesis) – cultivated in the tropics. Measurements were conducted in Ghana and allometric equations were applied to estimate biomass. The largest C potential was found in the rubber plantations (214 tC/ha). Cocoa (65 t...

  19. Aspen Plus在换热器工艺选型物性计算中的应用%Application of Plus Aspen in Physical Property Calculation for Technique Lectotype of Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    姚立影; 常春梅; 唐海; 姚炜屹

    2016-01-01

    The thermal physical properties of the saturated moist air, the flue gas and the mixed feeding of the hydrogen heat exchanger are calculated by applying the Plus Aspen software, including the density, viscosity, thermal conductibity coefficient, specific heat capacity and etc. Then the results are compared with the reported values or the measured values. It shows that the deviation between the calculated values from the Plus Aspen and the reported values is less than 13%which meets the engineering requirements so that it's of great preference for the design of the heat exchanger.%应用Aspen Plus 软件对饱和湿空气、烟气及加氢换热器混合进料的热物性进行计算,包括换热器设计所涉及的密度、黏度、导热系数、比热容等物性参数,并将计算结果与文献值或实测值进行比较。结果表明,基于Aspen Plus的计算结果与文献值最大偏差不超过13%,满足工程要求,可以为换热器设计提供参考依据。

  20. 基于Aspen Plus物性分析计算甲醇水溶液凝固点%Calculation for freezing points of methanol aqueous solution based on property analysis of Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    刘光明; 王伟鹏

    2013-01-01

    探讨了气液固多相平衡的机理,利用活度系数法计算各相热力学性质,采用Aspen plus物性分析计算不同浓度的甲醇水溶液凝固点,将计算结果与手册值进行比较,结果表明:模拟计算结果与手册值较为接近,在工程误差允许的范围内,可以用Aspen plus物性分析计算甲醇水溶液凝固点.%The multiphase balance mechanism of gas,liquid and solid was discussed.The thermodynamic properties of which were calculated by activity coefficient method.The freezing points of the methanol aqueous solution with different concentrations were calculated using the properties analysis of Aspen Plus.The results show that the simulation result is much close to the manual value.Within the allowed range of engineering error,the freezing points of the methanol aqueous solution can be simulated based on properties analysis of Aspen Plus and used in the practical engineering.

  1. Application of Aspen Plus in the Practical Teaching of Chemical Technology%基于 Aspen Plus 在化工工艺学教学中的应用

    Institute of Scientific and Technical Information of China (English)

    唐新宜

    2016-01-01

    化工工艺学是一门理论与生产相结合的课程。本文讨论了化工流程模拟软件Aspen与化工工艺学教学的关系,将Aspen Plus流程模拟软件逐步引入到化工工艺学实践教学中,加深了学生对化工生产工艺的理解,并提高了学生利用工具解决实际问题的能力。引入Aspen Plus软件作为化工工艺学教学辅助工具,能使教学更接近实际生产过程,拓宽了学生的视野。%Chemical Technology is a rather practical course .The relationship between Aspen Plus software and Chemical Technology were discussed .Aspen Plus software was introduced in the teaching of Chemical Technology course to strengthen the understanding of Chemical Engineering courses and improve the hands-on and implementing ability of the students , which made the teaching closer to engineering practice and broaden the students ’visual field.

  2. The Rise of Netpolitik: How the Internet Is Changing International Politics and Diplomacy. A Report of the Annual Aspen Institute Roundtable on Information Technology (11th, Aspen, Colorado, August 1-4, 2002).

    Science.gov (United States)

    Bollier, David

    This document is an interpretive synthesis of the discussion at a conference sponsored by the Aspen Institute that sought to develop new ways to understand how the Internet is changing the powers of the nation-state, the conduct of international relations, and the definitions of nation security. This report examines how the Internet and other…

  3. Process simulation and maximization of energy output in chemical-looping combustion using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Xiao Zhang, Subhodeep Banerjee, Ling Zhou, Ramesh Agarwal

    2015-01-01

    Full Text Available Chemical-looping combustion (CLC is currently considered as a leading technology for reducing the economic cost of CO2 capture. In this paper, several process simulations of chemical-looping combustion are conducted using the ASPEN Plus software. The entire CLC process from the beginning of coal gasification to the reduction and oxidation of the oxygen carrier is modeled and validated against experimental data. The energy balance of each major component of the CLC process, e.g., the fuel and air reactors and air/flue gas heat exchangers is examined. Different air flow rates and oxygen carrier feeding rates are used in the simulations to obtain the optimum ratio of coal, air, and oxygen carrier that produces the maximum power. Two scaled-up simulations are also conducted to investigate the influence of increase in coal feeding on power generation. It is demonstrated that the optimum ratio of coal, air supply, and oxygen carrier for maximum power generation remains valid for scaled-up cases with substantially larger coal feeding rates; the maximum power generation scales up linearly by using the process simulation models in ASPEN Plus. The energy output from four different types of coals is compared, and the optimum ratio of coal, air supply and oxygen carrier for maximum power generation for each type of coal is determined.

  4. Vegetation of birch and aspen forests in the Pinega State Reserve

    Directory of Open Access Journals (Sweden)

    Sergey Yu. Popov

    2017-05-01

    Full Text Available The Pinega State Nature Reserve (Russia is located in the Arkhangelsk region in the northern taiga subzone. Together with spruce forests and mires, birch forests represent one of the most wide-spread plant communities of its territory. Birch forests cover 24.6% of the Reserve's area. Aspen forests are rare plant communities in the Pinega Reserve. These forests cover only 0.9% of the whole Reserve's area. The birch and aspen forests vegetation has been classified based on 82 relevès. Eleven associations could be distinguished, which represent six groups of associations. Detailed characteristics of these syntaxa are provided including their biodiversity analysis. The analysis allowed establishing that the revealed syntaxa differ in relation to habitat environmental conditions: e.g., soil moisture, trophicity, nitrogen saturation and soil acidity. Sphagnum and blueberry birch forests proved to be the poorest in nitrogen, in contrast to the richest humidoherbaceous and broad-grassed groups of birch forest associations. Broad-grassed birch forests in the Pinega Reserve inhabit the most drained locations, while humidoherbaceous and Sphagnum forests occur in lesser drained locations.

  5. Simulated control in Aspen Dynamics for the production of limonene epoxide at pilot scale

    Directory of Open Access Journals (Sweden)

    Yeison Agudelo Arenas

    2016-12-01

    Full Text Available In this contribution is reported the study and analysis of the control system (simulated for the process of obtaining limonene epoxide. The modelling of the process at pilot scale was implemented in the software Aspen Plus from literature reports. Aspen Dynamics was used for the study of the process control. The model allows observing the behavior of the variables of interest in the process such as outflows from the distillation tower, heat duty, operating temperaturas and purity of the final product (limonene epoxide. The performance of the controllers (level, flow and temperature was evaluated by simulating disturbances (+30% in the feedstream to the process. Sensitivity analysis and preliminary design specifications allow to conclude that according to the simulations it is possible to obtain limonene epoxide (97,5% w/w with this system. The results of this work can be used for more detailed studies of the system, including experimental study designs that help to determine the operating point for the process variables which increase limonene epoxide production.

  6. Can elevated CO2 and ozone shift the genetic composition of aspen (Populus tremuloides) stands?

    Science.gov (United States)

    Moran, Emily V; Kubiske, Mark E

    2013-04-01

    The world's forests are currently exposed to increasing concentrations of carbon dioxide (CO2) and ozone (O3). Both pollutants can potentially exert a selective effect on plant populations. This, in turn, may lead to changes in ecosystem properties, such as carbon sequestration. Here, we report how elevated CO2 and O3 affect the genetic composition of a woody plant population via altered survival. Using data from the Aspen free-air CO2 enrichment (FACE) experiment (in which aspen clones were grown in factorial combinations of CO2 and O3), we develop a hierarchical Bayesian model of survival. We also examine how survival differences between clones could affect pollutant responses in the next generation. Our model predicts that the relative abundance of the tested clones, given equal initial abundance, would shift under either elevated CO2 or O3 as a result of changing survival rates. Survival was strongly affected by between-clone differences in growth responses. Selection could noticeably decrease O3 sensitivity in the next generation, depending on the heritability of growth responses and the distribution of seed production. The response to selection by CO2, however, is likely to be small. Our results suggest that the changing atmospheric composition could shift the genotypic composition and average pollutant responses of tree populations over moderate timescales.

  7. Severe obesity: a growing health concern A.S.P.E.N. should not ignore.

    Science.gov (United States)

    Shikora, Scott A

    2005-01-01

    The definition of malnutrition in the published standards of the American Society of Parenteral and Enteral Nutrition (A.S.P.E.N.) is any derangement in the normal nutrition status and includes overnutrition, commonly referred to as obesity. The incidence of obesity is increasing and reaching epidemic proportions in the United States and even worldwide. This has significant financial impact as our society spends billions of dollars on fad diets, commercial weight-loss programs, nutrition and dietary supplements, prescription and over-the-counter medications, and health clubs. Another approximately dollars 100 billion are spent to treat the medical consequences of obesity. Currently, for those patients with intractable morbid obesity, defined as having a body mass index >40 kg/m2, surgery offers the only option for achieving meaningful and sustainable weight loss. The resultant weight loss dramatically improves health and decreases the cost of health care for these patients. Years of refinement in technology and the introduction of safer and less invasive procedures have dramatically reduced the short-term morbidities and long-term metabolic consequences of these procedures. This address will review the field of weight loss (bariatric) surgery and will offer a compelling request for A.S.P.E.N. to include obesity in its fabric.

  8. Study of reproductive barriers in the production of P. elliottii x P. caribaea hybrid seed

    CSIR Research Space (South Africa)

    Sivlal, A

    2010-09-01

    Full Text Available Since its introduction, the P. elliottii (Pe) x P. caribaea var. hondurensis (Pch) hybrid has played a very important role in the plantation forestry industry due to its displayed improved growth, desirable wood properties (Du Plooy, 1984; Malan...

  9. Climatic Sensitivity of a Mixed Forest Association of White Spruce and Trembling Aspen at Their Southern Range Limit

    Directory of Open Access Journals (Sweden)

    Sophan Chhin

    2016-10-01

    Full Text Available Climatic sensitivity of white spruce (Picea glauca (Moench Voss was examined growing in association with trembling aspen (Populus tremuloides Michx. at their southern limit of distribution in a transitional ecotone between the southern boreal forest and northern prairie region. The study was carried out in the Spruce Woods Provincial Park (SWPP located in southwestern Manitoba, Canada. The dry regional climate restricted trembling aspen growth during the growing season via moisture deficiency and temperature induced drought stress. Warm, mild winters also negatively affected radial growth of trembling aspen. Growth of white spruce was moderated by conditions within the aspen stands as radial growth patterns showed low variability from year to year, a low common growth signal, and a stronger response to temperature than to precipitation. Nonetheless, the dry regional climate still restricted growth of white spruce during the growing season via temperature induced drought stress. The findings of the study for white spruce support the stress gradient hypothesis in which facilitative interactions between tree species are expected under harsher environmental conditions.

  10. 77 FR 31351 - Adequacy Determination for Aspen PM10 and Fort Collins Carbon Monoxide Maintenance Plans' Motor...

    Science.gov (United States)

    2012-05-25

    ... 93.118(e)(4), which was promulgated August 15, 1997 (62 FR 43780). We described our process for... (69 FR 40004). In addition, in certain areas with monitored ambient carbon monoxide (CO) values... AGENCY Adequacy Determination for Aspen PM and Fort Collins Carbon Monoxide Maintenance Plans'...

  11. Assessment of aspen ecosystem vulnerability to climate change for the Uinta-Wasatch-Cache and Ashley National Forests, Utah

    Science.gov (United States)

    Janine Rice; Tim Bardsley; Pete Gomben; Dustin Bambrough; Stacey Weems; Allen Huber; Linda A. Joyce

    2017-01-01

    Aspen ecosystems are valued because they add biodiversity and ecological value to the landscape. They provide rich and productive habitats and increase aesthetic value. Climate change poses the risk of altering and disrupting these ecosystems, and it may worsen the effects of non-climate stressors. To provide scientific information for land managers facing the...

  12. Wood-inhabiting, polyporoid fungi in aspen-dominated forests managed for biomass in the U.S. Lake States

    Science.gov (United States)

    Nicholas J. Brazee; Daniel L. Lindner; Shawn Fraver; Anthony W. D' Amato; Amy M. Milo

    2012-01-01

    To better understand the potential long-term effects of biomass harvesting on biodiversity, the polyporoid fungi community was characterized from 120 plots in four aspen-dominated forests in Minnesota. Four deadwood variables (substratum species, substratum type, decay class and diameter class) were recorded for each polyporoid species occurrence. A total of 2358...

  13. Acute O 3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment.

    Science.gov (United States)

    Darbah, Joseph N T; Jones, Wendy S; Burton, Andrew J; Nagy, John; Kubiske, Mark E

    2011-09-01

    We studied the effect of high ozone (O(3)) concentration (110-490 nmol mol(-1)) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O(3) pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O(3) exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O(3) and/or CO(2) for 12 years, were harvested. Acute O(3) damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O(3) damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O(3) damage as it directly controlled O(3) uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O(3) exposure. Moreover, elevated CO(2) did not ameliorate the adverse effects of acute O(3) dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O(3) levels.

  14. Acute O3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment

    Energy Technology Data Exchange (ETDEWEB)

    Darbah, J.N.; Nagy, J.; Jones, W. S.; Burton, A. J.; Kubiske, M. E.

    2011-10-01

    We studied the effect of high ozone (O{sub 3}) concentration (110-490 nmol mol{sup -1}) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O{sub 3} pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O{sub 3} exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O{sub 3} and/or CO{sub 2} for 12 years, were harvested. Acute O{sub 3} damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O{sub 3} damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O{sub 3} damage as it directly controlled O{sub 3} uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O{sub 3} exposure. Moreover, elevated CO{sub 2} did not ameliorate the adverse effects of acute O{sub 3} dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O{sub 3} levels.

  15. Using aspen for artist stretcher frames: adding value through quality service, direct marketing, and careful material selection

    Science.gov (United States)

    Chris. Polson

    2001-01-01

    Aspen wood, when carefully selected and kiln dried, makes excellent stock for artist stretcher frames. Direct marketing techniques including the Internet and word of mouth give access to national markets, providing a more diverse and stable customer base for operations from a rural area. High-quality service, as shown by product performance and rapid order fulfillment...

  16. Semi-Interpenetrating polymer network hydrogels based on aspen hemicellulose and chitosan: Effect of crosslinking sequence on hydrogel properties

    Science.gov (United States)

    Muzaffer Ahmet Karaaslan; Mandla A. Tshabalala; Gisela. Buschle-Diller

    2012-01-01

    Semi-interpenetrating network hydrogel films were prepared using hemicellulose and chemically crosslinked chitosan. Hemicellulose was extracted from aspen by using a novel alkaline treatment and characterized by HPSEC, and consisted of a mixture of high and low molecular weight polymeric fractions. HPLC analysis of the acid hydrolysate of the hemicellulose showed that...

  17. Analysis of CO2 Separation by Selexol Based on Aspen Plus%基于Aspen Plus对Selexol分离CO2流程的分析

    Institute of Scientific and Technical Information of China (English)

    邱朋华; 李丹丹; 徐宝龙; 呼姚; 杜昌帅; 吴少华

    2014-01-01

    整体煤气化联合循环发电系统可采取燃烧前捕集CO2的方法,处理的合成气量少,能耗低,且能够实现 CO2的近零排放,在 CO2脱除方面具有很大的优势。文中基于Aspen Plus 对 CO2/H2S 联合脱除和分别脱除流程建立了模型,对2流程的能耗、CO2及H2S的脱除效率以及Selexol溶液的再生性能进行了分析。得出:在出口 CO2纯度相同的情况下,CO2/H2S联合脱除流程的能耗仅占CO2/H2S分别脱除的21%左右,CO2脱除效率高于分别脱除流程,2流程Selexol溶液的再生性能相差不大,且H2S脱除效率也可达到95%以上,因此CO2/H2S联合脱除流程更经济。%Integrated gasification combined cycle (IGCC)power generation system can adopt pre-combustion CO2 capture methods, handling with less syngas and have low energy consumption, which can achieve near-zero emissions of CO2, resulting in great advantages in terms of CO2 removal. Based on Aspen Plus, combined removal of CO2/H2S (CRCH) and separate removal of CO2/H2S (SRCH) were modeled . Energy consumption, capture efficiency of CO2 and H2S, as well as the regeneration performance of Selexol were analyzed by the two models. The results indicate that:while keeping the same CO2 purity in outlet stream, the energy consumption of CRCH accounts for only 21% of SRCH; the CO2 capture efficiency is higher than that of SRCH, the regeneration performance of Selexol is almost the same for the two processes, and the capture efficiency of H2S in the two processes can be higher than 95%. All those prove that CRCH is more economic than SRCH.

  18. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  19. Phenology of the oil palm interspecific hybrid Elaeis oleifera × Elaeis guineensis

    OpenAIRE

    Paola Hormaza; Eloina Mesa Fuquen; Hernán Mauricio Romero

    2012-01-01

    Oil palm is one of the most important oil crops in the world. Because of its high productivity and perennial nature, it has been expanding quickly. Commercial plantations consist mostly of the African palm E. guineensis Jacq. However, producers in Latin America are increasingly planting the O × G interspecific hybrid, a cross between African palm (E. guineensis) and the American palm (E. oleifera (Kunth) Cortés). This interspecific hybrid has emerged as a promising solution to diseases such a...

  20. Response Surface Methodology and Aspen Plus Integration for the Simulation of the Catalytic Steam Reforming of Ethanol

    Directory of Open Access Journals (Sweden)

    Bernay Cifuentes

    2017-01-01

    Full Text Available The steam reforming of ethanol (SRE on a bimetallic RhPt/CeO2 catalyst was evaluated by the integration of Response Surface Methodology (RSM and Aspen Plus (version 9.0, Aspen Tech, Burlington, MA, USA, 2016. First, the effect of the Rh–Pt weight ratio (1:0, 3:1, 1:1, 1:3, and 0:1 on the performance of SRE on RhPt/CeO2 was assessed between 400 to 700 °C with a stoichiometric steam/ethanol molar ratio of 3. RSM enabled modeling of the system and identification of a maximum of 4.2 mol H2/mol EtOH (700 °C with the Rh0.4Pt0.4/CeO2 catalyst. The mathematical models were integrated into Aspen Plus through Excel in order to simulate a process involving SRE, H2 purification, and electricity production in a fuel cell (FC. An energy sensitivity analysis of the process was performed in Aspen Plus, and the information obtained was used to generate new response surfaces. The response surfaces demonstrated that an increase in H2 production requires more energy consumption in the steam reforming of ethanol. However, increasing H2 production rebounds in more energy production in the fuel cell, which increases the overall efficiency of the system. The minimum H2 yield needed to make the system energetically sustainable was identified as 1.2 mol H2/mol EtOH. According to the results of the integration of RSM models into Aspen Plus, the system using Rh0.4Pt0.4/CeO2 can produce a maximum net energy of 742 kJ/mol H2, of which 40% could be converted into electricity in the FC (297 kJ/mol H2 produced. The remaining energy can be recovered as heat.

  1. Significant increase in ecosystem C can be achieved with sustainable forest management in subtropical plantation forests.

    Directory of Open Access Journals (Sweden)

    Xiaohua Wei

    Full Text Available Subtropical planted forests are rapidly expanding. They are traditionally managed for intensive, short-term goals that often lead to long-term yield decline and reduced carbon sequestration capacity. Here we show how it is possible to increase and sustain carbon stored in subtropical forest plantations if management is switched towards more sustainable forestry. We first conducted a literature review to explore possible management factors that contribute to the potentials in ecosystem C in tropical and subtropical plantations. We found that broadleaves plantations have significantly higher ecosystem C than conifer plantations. In addition, ecosystem C increases with plantation age, and reaches a peak with intermediate stand densities of 1500-2500 trees ha⁻¹. We then used the FORECAST model to simulate the regional implications of switching from traditional to sustainable management regimes, using Chinese fir (Cunninghamia lanceolata plantations in subtropical China as a study case. We randomly simulated 200 traditional short-rotation pure stands and 200 sustainably-managed mixed Chinese fir--Phoebe bournei plantations, for 120 years. Our results showed that mixed, sustainably-managed plantations have on average 67.5% more ecosystem C than traditional pure conifer plantations. If all pure plantations were gradually transformed into mixed plantations during the next 10 years, carbon stocks could rise in 2050 by 260.22 TgC in east-central China. Assuming similar differences for temperate and boreal plantations, if sustainable forestry practices were applied to all new forest plantation types in China, stored carbon could increase by 1,482.80 TgC in 2050. Such an increase would be equivalent to a yearly sequestration rate of 40.08 TgC yr⁻¹, offsetting 1.9% of China's annual emissions in 2010. More importantly, this C increase can be sustained in the long term through the maintenance of higher amounts of soil organic carbon and the production

  2. Significant increase in ecosystem C can be achieved with sustainable forest management in subtropical plantation forests.

    Science.gov (United States)

    Wei, Xiaohua; Blanco, Juan A

    2014-01-01

    Subtropical planted forests are rapidly expanding. They are traditionally managed for intensive, short-term goals that often lead to long-term yield decline and reduced carbon sequestration capacity. Here we show how it is possible to increase and sustain carbon stored in subtropical forest plantations if management is switched towards more sustainable forestry. We first conducted a literature review to explore possible management factors that contribute to the potentials in ecosystem C in tropical and subtropical plantations. We found that broadleaves plantations have significantly higher ecosystem C than conifer plantations. In addition, ecosystem C increases with plantation age, and reaches a peak with intermediate stand densities of 1500-2500 trees ha⁻¹. We then used the FORECAST model to simulate the regional implications of switching from traditional to sustainable management regimes, using Chinese fir (Cunninghamia lanceolata) plantations in subtropical China as a study case. We randomly simulated 200 traditional short-rotation pure stands and 200 sustainably-managed mixed Chinese fir--Phoebe bournei plantations, for 120 years. Our results showed that mixed, sustainably-managed plantations have on average 67.5% more ecosystem C than traditional pure conifer plantations. If all pure plantations were gradually transformed into mixed plantations during the next 10 years, carbon stocks could rise in 2050 by 260.22 TgC in east-central China. Assuming similar differences for temperate and boreal plantations, if sustainable forestry practices were applied to all new forest plantation types in China, stored carbon could increase by 1,482.80 TgC in 2050. Such an increase would be equivalent to a yearly sequestration rate of 40.08 TgC yr⁻¹, offsetting 1.9% of China's annual emissions in 2010. More importantly, this C increase can be sustained in the long term through the maintenance of higher amounts of soil organic carbon and the production of timber products

  3. 基于Aspen Plus的自复叠热泵模拟%The Simulation of Auto-Cascade Heat Pump Ssystem Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    刘金平; 朱海明; 刘雪峰

    2010-01-01

    自复叠热泵的变工况运行对其性能影响很大.应用Aspen Plus软件,对冷凝器入口水温从40~55℃的4个工况下的自复叠热泵进行了流程模拟,并对流程中各点参数变化进行了分析,对节流阀的流态进行了计算分析.结果表明,自复叠热泵在两个节流阀开度不变时,随着冷凝器入口水温的升高,压缩机耗功增加,主流与支流流量增大,蒸发压力升高,压缩机入口比容减小,循环的质量流量增大;两个节流阀均未达到雍塞流.

  4. Pulverized Coal Gasification Simulation Based on Aspen Plus Software%基于Aspen Plus的粉煤气化模拟

    Institute of Scientific and Technical Information of China (English)

    张宗飞; 汤连英; 吕庆元; 章卫星; 何正兆; 毕东煌

    2008-01-01

    Aspen Plus为模拟工具,选择反应平衡模型,并应用Gibbs自由能最小化方法建立了Shell粉煤气化模型;通过对神华、沾化和天碱煤种的气化模拟,对建立的模型进行了检验,结果表明:用N2输送粉煤的气化过程能够很好地模拟,而用CO2输送粉煤的气化过程模拟偏差较大.以沾化煤种为例,检验了气化炉散热损失取煤总热值约2%的合理性;研究了不同操作条件下的气化性能,结果表明:提高温度和压力可使气化过程得到强化.

  5. Influence de la mortalité des cacaoyers sur la stabilité de la production dans une plantation industrielle

    Directory of Open Access Journals (Sweden)

    Bastide, P.

    2008-01-01

    Full Text Available Effect of Cocoa Tree Mortality on Production Stability in a Private Estate. Yields in a 1,674 ha cocoa estate were analysed in Indonesia. The plantation, which was set up between 1981 and 1990 at Ransiki (Papua province, benefited from suitable soil and climatic conditions: good rainfall distribution and rich soils. The planting material comprised hybrids of various origins, Amelonados and local selections. Density measurements inside the plantation revealed a gradual reduction in the number of cocoa trees, from 1,250 at the outset to 835 trees/ha after 21 years. At the same time, overall yields for the same period remained stable. Cocoa tree mortality, which was responsible for the gradual reduction in density, did not affect production; neither did it alter the uniformity of the plant cover in the plots. This situation reflected an increase in tree productivity. The conditions for stabilized cocoa yields appeared to be linked not only to suitable edapho-climatic conditions and limited parasite pressure, but also to the ability of cocoa trees to increase their yields in conditions of decreasing stand due to the natural thining of the original plant population.

  6. A new density model of Cryptomeria fortunei plantation

    Institute of Scientific and Technical Information of China (English)

    Jiang Xidian; Huang Langzeng; Chen Baohui

    2006-01-01

    According to the volume increase model of an average individual tree in a plant population and the theory of invariable final output,we put forward a new density model of plant population: V-β=ANβ+B.Here N means the stand density and V stands for average individual tree volume;A,B and β are parameters that change with growth stage.Using the density variation of standard plots of Cryptromeriafortunei plantation to verify the new model,it turns out that this model can well simulate the population density effect law of C.fortunei plantation,and it is markedly better and shows higher accuracy than the commonly used reciprocal model of density effect and secondary-effect model.Let β=1,we can obtain the reciprocal model of density effect,which means the reciprocal model of density effect is only a special case of this new model.

  7. Growth and yield models for Dahurian larch plantations

    Institute of Scientific and Technical Information of China (English)

    Yuan Jinlan

    1999-01-01

    Several equations were seiected using nonlinear regression analysis for setting up growth and yield models of Dahurian larch (Larix gmelinii Rupr.) plantations. Data of 405 stem analysis trees were collected from 336 temporary plots throughout the Daxing'an Mountains. Results showed that the Richards equation was the best model for estimating tree height, stand mean height and stand dominant height by age; the Power equation was the fittest model for predicting tree volume by DBH and tree height, and the Logarithmic stand volume equation was good for predicting stand volume from age, mean height, basal area and other stand variables. These models can be used to construct volume tables, site index table and other forestry tables for Dahurian plantations.

  8. Resinous plants as an economic alternative to bioenergy plantations

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, J.J.

    1985-10-01

    The resin-producing xerophytic species Grindelia camporum is an economical alternative for bioenergy plantations in arid lands. A hypothetical bioenergy farm consists of the land and agricultural facilities needed to grow, harvest and transport 272,100 Mg of biomass to the central processing plant, where the plant material is extracted and the bagasse is converted into electricity. A farm of this type could produce plant extractives that are equivalent to crude oil, with a net positive energy balance. Economic analyses of a series of scenarios based on a plantation of this size indicate that bioenergy production in arid lands must be integrated with the generation of higher-priced chemica commodities, such as naval stores rosin.

  9. SOCIAL EXCLUSION: GUATEMALAN YOUTH WITHIN COFFEE PLANTATIONS AT SOCONUSCO CHIAPAS

    OpenAIRE

    2014-01-01

    Mexico's southern border is the entry point for different migratory flows, mainly from Central America, these flows have taken place under socioeconomic contexts and conditions which demand the constant livelihood strategies pursuit from people. This paper is focused on the agricultural laborers from Guatemalan origin, within coffee plantation farms at the Soconusco, Chiapas. The main objective is arguing how the lack of access -or restricted access- to education and the precarious inclus...

  10. Nitrogen deposition enhances carbon sequestration by plantations in northern China.

    Science.gov (United States)

    Du, Zhihong; Wang, Wei; Zeng, Wenjing; Zeng, Hui

    2014-01-01

    Nitrogen (N) deposition and its ecological effects on forest ecosystems have received global attention. Plantations play an important role in mitigating climate change through assimilating atmospheric CO2. However, the mechanisms by which increasing N additions affect net ecosystem production (NEP) of plantations remain poorly understood. A field experiment was initialized in May 2009, which incorporated additions of four rates of N (control (no N addition), low-N (5 g N m⁻² yr⁻¹), medium-N (10 g N m⁻² yr⁻¹), and high-N (15 g N m⁻² yr⁻¹) at the Saihanba Forestry Center, Hebei Province, northern China, a locality that contains the largest area of plantations in China. Net primary production (NPP), soil respiration, and its autotrophic and heterotrophic components were measured. Plant tissue carbon (C) and N concentrations (including foliage, litter, and fine roots), microbial biomass, microbial community composition, extracellular enzyme activities, and soil pH were also measured. N addition significantly increased NPP, which was associated with increased litter N concentrations. Autotrophic respiration (AR) increased but heterotrophic respiration (HR) decreased in the high N compared with the medium N plots, although the HR in high and medium N plots did not significantly differ from that in the control. The increased AR may derive from mycorrhizal respiration and rhizospheric microbial respiration, not live root respiration, because fine root biomass and N concentrations showed no significant differences. Although the HR was significantly suppressed in the high-N plots, soil microbial biomass, composition, or activity of extracellular enzymes were not significantly changed. Reduced pH with fertilization also could not explain the pattern of HR. The reduction of HR may be related to altered microbial C use efficiency. NEP was significantly enhanced by N addition, from 149 to 426.6 g C m⁻² yr⁻¹. Short-term N addition may significantly enhance

  11. Investment appraisal of a poplar plantation aged 42 years

    Directory of Open Access Journals (Sweden)

    Keča Ljiljana

    2013-01-01

    Full Text Available Commercial profitability of poplar cultivation was analyzed in an artificial poplar plantation in Serbia. The aim of this study was to validate the invested financial means in the artificial poplar plantation, on the basis of the analysis of costs and receipts during a 42-year rotation, on alluvial semigley, at a discount rate of 12%. Methods of dynamic investment calculation (net present value - NPV, internal rate of return - IRR, benefit-cost method - B/C and payback period - PBP were used. The investigated plantations were established from Populus x euramericana cl. I-214, with a planting spacing of 6 x 3 m. At the calculation discount rate of 12%, the project for the production cycle of 42 years was not cost-effective from the economic aspect. The discount rate of 6% can be accepted in the studied plot because of the better site (alluvial semigley, but the oldness of the stand is unfavourable. For the studied sample plot, IRR was 5.51 %. B/C at r=12% in the study compartment was 0.24. The analysis shows that PBP is practically unacceptable for the investor at the discount rate of 6%. In practice, it is necessary to improve the position of producers in getting financial means for investment in poplar cultivation, so as to stimulate the establishment of artificial poplar plantations, especially in the private sector (on private land. [Projekat Ministarstva nauke Republike Srbije, br. TR 37008, TR 31041 and Value chain of non-wood forest products and its role in development of forestry sector in Serbia

  12. Energy plantation for solving the crisis of fuel and energy

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, O.P.

    1985-10-01

    Concentrated efforts are required for achieving better social foresty in rural areas of India. There are a large number of tree species that can be considered for energy plantations. Some of the fuel wood plants are described: subabul, eucalyptus, agathi, babul, ber, casuarina, imli, karanji, pardeshibabul, siris, jamun, and neem. Carbohydrate plants contain sugar and starch and serve as the source of energy in the form of food and fuel. The latex of some plants can be processed as fuel oil. (Refs. 29).

  13. Comparison of four harvesting systems in a loblolly pine plantation

    Science.gov (United States)

    J. Klepac; Dana Mitchell

    2016-01-01

    Felling and skidding operations were monitored while clearcut harvesting a 12-acre area of a 14-year old loblolly pine (Pinus taeda) plantation. The study area contained 465 trees per acre for trees 2.0 inches Diameter at Breast Height (DBH) and larger with a Quadratic Mean Diameter (QMD) of 7.26 inches. Two feller-bunchers (tracked and rubber-tired) and two skidders (...

  14. Comparison of insect biodiversity between organic and conventional plantations in Kodagu, Karnataka, India

    Directory of Open Access Journals (Sweden)

    S. Mone

    2014-08-01

    Full Text Available We undertook a comparative analysis of ground insects and fruit eating butterflies on 29 different plantations in Kodagu District of Karnataka which is one of the rich biodiversity zones of the Western Ghats. These included organic and conventional coffee and cardamom plantations using different levels of chemical fertilizers and pesticides. A total number of 457 ground insect species were collected using pit-fall traps which included 92 species of ants and 123 species of beetles, among other insect taxa that we measured. Similarly, 25 species of butterflies belonging to the family Nymphalidae were collected using bait traps. We found a clear negative effect on the ground insect species diversity (Shannon index and evenness (Shannon evenness index in pesticide treated plantations as compared to the organic plantations. A similar negative effect was observed for butterfly diversity in plantations using pesticides. Our results corroborate the value of organic plantations in supporting higher levels of biodiversity.

  15. Contributions of a global network of tree diversity experiments to sustainable forest plantations.

    Science.gov (United States)

    Verheyen, Kris; Vanhellemont, Margot; Auge, Harald; Baeten, Lander; Baraloto, Christopher; Barsoum, Nadia; Bilodeau-Gauthier, Simon; Bruelheide, Helge; Castagneyrol, Bastien; Godbold, Douglas; Haase, Josephine; Hector, Andy; Jactel, Hervé; Koricheva, Julia; Loreau, Michel; Mereu, Simone; Messier, Christian; Muys, Bart; Nolet, Philippe; Paquette, Alain; Parker, John; Perring, Mike; Ponette, Quentin; Potvin, Catherine; Reich, Peter; Smith, Andy; Weih, Martin; Scherer-Lorenzen, Michael

    2016-02-01

    The area of forest plantations is increasing worldwide helping to meet timber demand and protect natural forests. However, with global change, monospecific plantations are increasingly vulnerable to abiotic and biotic disturbances. As an adaption measure we need to move to plantations that are more diverse in genotypes, species, and structure, with a design underpinned by science. TreeDivNet, a global network of tree diversity experiments, responds to this need by assessing the advantages and disadvantages of mixed species plantations. The network currently consists of 18 experiments, distributed over 36 sites and five ecoregions. With plantations 1-15 years old, TreeDivNet can already provide relevant data for forest policy and management. In this paper, we highlight some early results on the carbon sequestration and pest resistance potential of more diverse plantations. Finally, suggestions are made for new, innovative experiments in understudied regions to complement the existing network.

  16. Process simulation of oxy-combustion for maximization of energy output using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Subhodeep Banerjee, Xiao Zhang, Suraj K. Puvvada, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Oxy-fuel combustion is a next-generation combustion technology that shows promise to address the need of low-cost carbon capture from fossil fueled power plants. Oxy-fuel combustion requires expensive pre-processing in an air separation unit to separate pure oxygen from air for the combustion process, which reduces the overall efficiency of the process. This paper employs ASPEN Plus process simulation software to model a simple oxy-fuel combustor and investigates the effect of various parameters on the energy output. The composition of the flue gas is carefully examined. The results of this study provide a starting point for optimized oxy-fuel combustion operation for maximum energy output, which will be crucial for future deployment of oxy-fuel combustion technology.

  17. Simulation and validation of chemical-looping combustion using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Ling Zhou, Zheming Zhang, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Laboratory-scale experimental studies have demonstrated that Chemical-Looping Combustion (CLC is an advanced technology which holds great potential for high-efficiency low-cost carbon capture. The generated syngas in CLC is subsequently oxidized to CO2 and H2O by reaction with an oxygen carrier. In this paper, process-level models of CLC are established in ASPEN Plus code for detailed simulations. The entire CLC process, from the beginning of coal gasification to reduction and oxidation of the oxygen carrier is modeled. The heat content of each major component such as fuel and air reactors and air/flue gas heat exchangers is carefully examined. Large amount of energy is produced in the fuel reactor, but energy needs to be supplied to the air reactor. The overall performance and efficiency of the modeled CLC systems are also evaluated.

  18. Changes in the microstructure and properties of aspen chemithermomechanical pulp fibres during recycling.

    Science.gov (United States)

    Fu, Yingjuan; Wang, Rongrong; Li, Dejuan; Wang, Zhaojiang; Zhang, Fengshan; Meng, Qinglin; Qin, Menghua

    2015-03-06

    The effects of recycling on the microstructure and properties of bleached aspen chemithermomechanical pulp (CTMP) fibres were systematically investigated. The low-temperature nitrogen adsorption and atomic force microscopy results showed that a substantial amount of large pores and most of the very small pores in the fibre wall closed and the fibre surface became less coarse and porous during recycling. The partial cocrystallisation of cellulose microfibrils took place, as reflected in the increment of the cellulose crystallinity and the width of the crystallite in the 0 0 2 lattice plane. These irreversible structural changes caused significant hornification of the recycled fibres, leading to the loss of swelling and bonding capability. The decrease of the tensile index, burst index, and tear index further demonstrated the deterioration of the fibre properties. However, the single-fibre strength considerably increased after recycling, which was mainly due to the enlarged cellulose aggregates in the fibre wall.

  19. 美国 ACUSON ASPEN SN31893彩超特殊故障 1例

    Institute of Scientific and Technical Information of China (English)

    张涛

    2001-01-01

    @@美国 ASPEN SN31893彩超系美国 ACUSON公司的最新一代产品,为新一代全功能彩超,该机型在部队医院拥有量较大,据对经销商了解还没有出现过类似的故障。 故障现象 开机后机器开始自检, 4MB DRAM OK。然后是 ACUSON ASPEN的杉树图象出现,机器进入 POWER DIAGNOSTICS,一段时间后出现错误提示:

  20. The Aspen Framework for Dark Matter Substructure Inference from Strong Gravitational Lensing Observations

    Science.gov (United States)

    Moustakas, Leonidas A.; Cyr-Racine, Francis-Yan; Keeton, Charles R.

    2016-01-01

    The properties of the dark matter particle or particles lead to different small scale halo populations, distributions, and evolution over cosmic time. We introduce a new method for characterizing the properties of substructure within galaxies through the power spectrum of potential fluctuations, and demonstrate how complete sets of multiwavelength imaging and time domain observations can be processed directly to infer all facets of the strong gravitational lensing components and source properties, including the dark matter substructure power spectrum constraints. We are able to take advantage of analysis parallels with cosmic background radiation techniques, and furthermore demonstrate how this technique, dubbed The Aspen Framework, reduces to the long-standing approach of working with reduced or derived observable quantities in lensing.

  1. Three Stage Equilibrium Model for Coal Gasification in Entrained Flow Gasifiers Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    KONG Xiangdong; ZHONG Weimin; DU Wenli; QIAN Feng

    2013-01-01

    A three stage equilibrium model is developed for coal gasification in the Texaco type coal gasifiers based on Aspen Plus to calculate the composition of product gas,carbon conversion,and gasification temperature.The model is divided into three stages including pyrolysis and combustion stage,char gas reaction stage,and gas phase reaction stage.Part of the water produced in the pyrolysis and combustion stage is assumed to be involved in the second stage to react with the unburned carbon.Carbon conversion is then estimated in the second stage by steam participation ratio expressed as a function of temperature.And the gas product compositions are calculated from gas phase reactions in the third stage.The simulation results are consistent with published experimental data.

  2. Carbohydrate reactions during high-temperature steam treatment of aspen wood.

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2005-06-01

    Aspen wood was treated with steam at different time-temperature severity factors. Analysis of the amounts of acids released revealed a relationship between the acidity and the formation of furfural and hydroxymethyl furfural as degradation products from carbohydrates. It is suggested that two concurrent or consecutive mechanisms are responsible for the observed results: a homolytic cleavage and an acid hydrolysis of glucosidic linkages in the polysaccharides. By preimpregnating the wood with alkali, hydrolysis can be eliminated, resulting in a much cleaner depolymerization of the polysaccharides without any further acid-catalyzed degradation. The enzymatic digestibility of the steam-treated wood material for the formation of glucose was compared with that of steam-exploded wood. A more efficient route for glucose production from steam-exploded wood was found as long as the biomass-pretreated material was homogeneous and without shives.

  3. Evolution and environmental degradation of superhydrophobic aspen and black locust leaf surfaces

    Science.gov (United States)

    Tranquada, George Christopher

    The current study is focused on the characterization of four natural leaf species (quaking, bigtooth and columnar european aspen as well as black locust) possessing a unique dual-scale cuticle structure composed of micro- and nano-scale asperities, which are able to effectively resist wetting (superhydrophobic), characteristic of The Lotus Effect. Scanning Electron Microscopy (SEM) was used to track the growth and evolution of their distinctive nano-scale epicuticular wax (ECW) morphologies over one full growing season. In addition, the stability of their superhydrophobic property was tested in various environments. It was determined that the long-term stability of these surfaces is tentatively linked to various environmental stress factors. Specifically, a combination of high temperature and humidity caused the degradation of nanoscale asperities and loss of the superhydrophobic property. The dual-scale surface structure was found to provide a suitable template for the design of future superhydrophobic engineering materials.

  4. Aspen Global Change Institute: 25 Years of Interdisciplinary Global Change Science

    Energy Technology Data Exchange (ETDEWEB)

    Meehl, Gerald A.; Moss, Richard

    2016-11-01

    Global environmental changes such as climate change result from the interaction of human and natural systems. Research to understand these changes and options for addressing them requires the physical, environmental, and social sciences, as well as engineering and other applied fields. In this essay, we describe how the Aspen Global Change Institute (AGCI) has provided leadership in global change science over the past 25 years—in particular how it has contributed to the integration of the natural and social sciences needed to research the drivers of change, Earth system response, natural and human system impacts, and options for risk management. We illustrate the ways the history of AGCI has been intertwined with the evolution of global change science as it has become an increasingly interdisciplinary endeavor.

  5. Simulation and validation of chemical-looping combustion using ASPEN plus

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ling [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130 (United States); Zhang, Zheming; Agarwal, Ramesh K. [Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130 (United States)

    2013-07-01

    Laboratory-scale experimental studies have demonstrated that Chemical-Looping Combustion (CLC) is an advanced technology which holds great potential for high-efficiency low-cost carbon capture. The generated syngas in CLC is subsequently oxidized to CO2 and H2O by reaction with an oxygen carrier. In this paper, process-level models of CLC are established in ASPEN Plus code for detailed simulations. The entire CLC process, from the beginning of coal gasification to reduction and oxidation of the oxygen carrier is modeled. The heat content of each major component such as fuel and air reactors and air/flue gas heat exchangers is carefully examined. Large amount of energy is produced in the fuel reactor, but energy needs to be supplied to the air reactor. The overall performance and efficiency of the modeled CLC systems are also evaluated.

  6. THE WATER USE BY FOREST PLANTATIONS – A REVIEW

    Directory of Open Access Journals (Sweden)

    Silvana Lucia Caldato

    2013-08-01

    Full Text Available http://dx.doi.org/10.5902/1980509810562This review aims to present some of the main results and infer about the current state-of-the-art of the controversy related to the water use by forest plantations. Several studies have been carried out in this area in different regions, mainly in Australia, South Africa, Europe, India and Brazil. However, according to authors, the controversy persists and it is necessary that the scientific results are understood by the community in order to avoid the predominance of myths and half-truths. In this way, the current review intends to summarize some scientific results concerning the main hydrologic aspects of the plantations (interception, transpiration and catchment water balance, the relationship between the high productivity and the water use efficiency, and the importance of the establishment of forest management plan focused on the river watershed scale, in order to contribute to hydrological sustainability.  The results coincide that the relationship between the forest plantations and the water depends on the region, species, environmental conditions  and management practices on the watershed scale.

  7. Nitrogen-fixing bacteria in Eucalyptus globulus plantations.

    Science.gov (United States)

    da Silva, Marliane de Cássia Soares; Paula, Thiago de Almeida; Moreira, Bruno Coutinho; Carolino, Manuela; Cruz, Cristina; Bazzolli, Denise Mara Soares; Silva, Cynthia Canedo; Kasuya, Maria Catarina Megumi

    2014-01-01

    Eucalypt cultivation is an important economic activity worldwide. In Portugal, Eucalyptus globulus plantations account for one-third of the total forested area. The nutritional requirements of this crop have been well studied, and nitrogen (N) is one of the most important elements required for vegetal growth. N dynamics in soils are influenced by microorganisms, such as diazotrophic bacteria (DB) that are responsible for biological nitrogen fixation (BNF), so the aim of this study was to evaluate and identity the main groups of DB in E. globulus plantations. Samples of soil and root systems were collected in winter and summer from three different Portuguese regions (Penafiel, Gavião and Odemira). We observed that DB communities were affected by season, N fertilization and moisture. Furthermore Bradyrhizobium and Burkholderia were the most prevalent genera in these three regions. This is the first study describing the dynamic of these bacteria in E. globulus plantations, and these data will likely contribute to a better understanding of the nutritional requirements of eucalypt cultivation and associated organic matter turnover.

  8. Integrated Bali Cattle Development Model Under Oil Palm Plantation

    Directory of Open Access Journals (Sweden)

    Rasali Hakim Matondang

    2015-09-01

    Full Text Available Bali cattle have several advantages such as high fertility and carcass percentage, easy adaptation to the new environment as well. Bali cattle productivity has not been optimal yet. This is due to one of the limitation of feed resources, decreasing of grazing and agricultural land. The aim of this paper is to describe Bali cattle development integrated with oil palm plantations, which is expected to improve productivity and increase Bali cattle population. This integration model is carried out by raising Bali cattle under oil palm plantation through nucleus estate scheme model or individual farmers estates business. Some of Bali cattle raising systems have been applied in the integration of palm plantation-Bali cattle. One of the intensive systems can increase daily weight gain of 0.8 kg/head, calfcrop of 35% per year and has the potency for industrial development of feed and organic fertilizer. In the semi-intensive system, it can improve the production of oil palm fruit bunches (PFB more than 10%, increase harvested-crop area to 15 ha/farmer and reduce the amount of inorganic fertilizer. The extensive system can produce calfcrop ³70%, improve ³30% of PFB, increase business scale ³13 cows/farmer and reduce weeding costs ³16%. Integrated Bali cattle development may provide positive added value for both, palm oil business and cattle business.

  9. Fiscal and Monetary Policy for The Development of Indonesian Plantation

    Directory of Open Access Journals (Sweden)

    Suharyadi Suharyadi

    2011-09-01

    Full Text Available The global monetary crisis in 2007-2008 and the focus of development on climate changesmake it important to promote a healthy economic growth based on the local resources, Theeconomic crisis, which has slowed down the economic growth and has caused job losseswhich result in increasing unemployment and poverty, should alter the focus of Indonesianeconomic development in the future to be based on renewable and sustainable local resources.Indonesia is an agricultural and maritime country so these two aspects should be thecore of the growth. In agricultural culture, plantation sector is the source of sustainable economicgrowth because of its geographical, demographic, and cultural potentials. The problemsin plantation sector are the low growth of areas and productivity as well as its limitedend-products. The research findings indicated that in order to increase areas, there should bea guarantee on investment, interest rate, and little retribution or good governance. To increaseproductivity, we need a guarantee on fertilizer price, interest rate, and wages, as wellas pricing factors to avoid market distortion. This is very important relating to the economicstimulus policy which is essential to revitalize from the economic doom in the future.Keywords: plantation sector, area, productivity, investment, interest rate, and wages

  10. THE Eucalyptus sp. AGE PLANTATIONS INFLUENCING THE CARBON STOCKS

    Directory of Open Access Journals (Sweden)

    Charlote Wink

    2013-06-01

    Full Text Available http://dx.doi.org/10.5902/198050989279The tree growth and biomass accumulation, as well as the maintenance of forest residue at the soil surface can act in the removal of carbon from the atmosphere through the cycling process of plant material. The objective was to study the influence of Eucalyptus sp. Plantations with 20, 44 and 240 months of age on the variation of carbon in soil and biomass. The carbon in the soil depth was determined by CHNS auto-analyzer and carbon in the vegetation was determined by the biomass in each forest, considering a factor of 0.45 of the dry mass. We determined the density and particle size distribution of soil. For the comparison between plantations, there was analysis of variance and comparison of means of carbon in vegetation and soil, considering the 5% level of probability. The carbon content and stock in the soil were low, indicating that a natural feature of the category of Paleuldt, or the growth of eucalyptus forests, replacing the field native vegetation did not aggregate a significant increase in the carbon. Although, there was a significant increase carbon in aboveground biomass. It includes forest biomass and litter. So, despite the values ​​of carbon stocks are low, it identified a greater average total in the soil compared to the stock aboveground. Furthermore, this increase aboveground (tree and litter compartments can be considered significant between the eucalyptus plantations of different ages.

  11. Developmental Trends of Black Spruce Fibre Attributes in Maturing Plantations

    Directory of Open Access Journals (Sweden)

    Peter F. Newton

    2016-01-01

    Full Text Available This study assessed the temporal developmental patterns of commercially relevant fibre attributes (tracheid length and diameters, wall thickness, specific surface area, wood density, microfibril angle, fibre coarseness, and modulus of elasticity and their interrelationships within maturing black spruce (Picea mariana (Mill. B.S.P. plantations. A size-based stratified random sample procedure within 5 semimature plantations located in the Canadian Boreal Forest Region was used to select 50 trees from which radial cross-sectional xylem sequences at breast-height (1.3 m were cut and analyzed. Statistically, the graphical and linear correlation analyses indicated that the attributes exhibited significant (p≤0.05 relationships among themselves and with morphological tree characteristics. Relative variation of each annually measured attribute declined with increasing size class (basal area quintile. The transitional shifts in temporal correlation patterns occurring at the time of approximate crown closure where suggestive of intrinsic differences in juvenile and mature wood formation processes. The temporal cumulative development patterns of all 8 of the annually measured attributes varied systematically with tree size and exhibited the most rapid rates of change before the trees reached a cambial age of 20 years. At approximately 50 years after establishment, plantation mean attribute values were not dissimilar from those reported for more mature natural-origin stands.

  12. ECONOMIC EVALUATION OF Eucalyptus grandis PLANTATION FOR CELLULOSE PRODUCTION

    Directory of Open Access Journals (Sweden)

    Antonio Donizette de Oliveira

    2008-03-01

    Full Text Available The aims of this research were: to analyze the economic feasibility of planting eucalyptus for producing wood pulp,considering various site index and two spacings; to analyze the economic effects regarding the profitability of the forest activity indifferent distances from the industry and changes on discount rate, wood price, transportation costs, minimum profitable diameter oflogs and the length of the logs. A biometric model for making wood volume prognosis was developed, using data of a trial ofEucalyptus grandis stands 19 and 103 months old. The prognosis started at the age zero, considering logs of 2.5 and 6.0 m of lenghtand the minimum diameter varying from 4 to 10 cm, in intervals of 2 cm. Net Present Worth (NPW was used as the economic decisioncriterium, considering an infinite horizon. The main conclusions were: reducing the minimum profitable diameter and the length ofthe logs are good strategies to increase wood utilization and profit; plantations located in less productive lands are economicallyunfeasible; the cost of transportation has significant effect on the profitability of the forest activity and must be analyzed carefully atthe moment of defining the location of new plantations; small variations on wood sales price may cause big alterations on theprofitability of the forest activity, suggesting that the improvement of the wood quality together with other decisions that may increasewood price are alternatives that may render the plantations in less productive areas profitable.

  13. Estimation of Carbon Stocks in Coffee Plantation in East Java

    Directory of Open Access Journals (Sweden)

    Aris Wibawa

    2010-05-01

    Full Text Available Global warming is closely related with the amount of carbon stored in an ecosystem. A research to determine the amount of carbon stock in the coffee farms has been conducted in Sumberbaru and Silo Sub-districts in Jember district, Kaliwining Experimental Station (ES in Jember district, Sumberasin ES in Malang district and Andungsari ES in Bondowoso district. Carbon stock was measured using the method of Rapid Carbon Stock’s Assessment (RaCSA developed by ICRAF. Measurements were made on the observation plots of 200 m2, with 3 replications. Results of measurement of carbon stock on coffee plantations showed that the increased carbon stock was proportional with the age of plants. Carbon stock in coffee plantation depends on the shade tree system. In the monoculture coffee leucaena used as shade trees, the carbon stock was lower then in multistrata system (agroforestry used several kinds of shade trees. Carbon stock on coffee plant in the estate more than smallholder. The average of carbon stock on Robusta coffee at the age of 30 years amounted to 29.38 Mg ha-1, it is greater than the carbon deposit on Arabica coffee that is 22.02 Mg ha-1.Key words: Carbon stock, coffee plantation, Arabica, Robusta, smallholder, agroforestri

  14. Nitrogen-Fixing Bacteria in Eucalyptus globulus Plantations

    Science.gov (United States)

    da Silva, Marliane de Cássia Soares; Paula, Thiago de Almeida; Moreira, Bruno Coutinho; Carolino, Manuela; Cruz, Cristina; Bazzolli, Denise Mara Soares; Silva, Cynthia Canedo; Kasuya, Maria Catarina Megumi

    2014-01-01

    Eucalypt cultivation is an important economic activity worldwide. In Portugal, Eucalyptus globulus plantations account for one-third of the total forested area. The nutritional requirements of this crop have been well studied, and nitrogen (N) is one of the most important elements required for vegetal growth. N dynamics in soils are influenced by microorganisms, such as diazotrophic bacteria (DB) that are responsible for biological nitrogen fixation (BNF), so the aim of this study was to evaluate and identity the main groups of DB in E. globulus plantations. Samples of soil and root systems were collected in winter and summer from three different Portuguese regions (Penafiel, Gavião and Odemira). We observed that DB communities were affected by season, N fertilization and moisture. Furthermore Bradyrhizobium and Burkholderia were the most prevalent genera in these three regions. This is the first study describing the dynamic of these bacteria in E. globulus plantations, and these data will likely contribute to a better understanding of the nutritional requirements of eucalypt cultivation and associated organic matter turnover. PMID:25340502

  15. Nitrogen-fixing bacteria in Eucalyptus globulus plantations.

    Directory of Open Access Journals (Sweden)

    Marliane de Cássia Soares da Silva

    Full Text Available Eucalypt cultivation is an important economic activity worldwide. In Portugal, Eucalyptus globulus plantations account for one-third of the total forested area. The nutritional requirements of this crop have been well studied, and nitrogen (N is one of the most important elements required for vegetal growth. N dynamics in soils are influenced by microorganisms, such as diazotrophic bacteria (DB that are responsible for biological nitrogen fixation (BNF, so the aim of this study was to evaluate and identity the main groups of DB in E. globulus plantations. Samples of soil and root systems were collected in winter and summer from three different Portuguese regions (Penafiel, Gavião and Odemira. We observed that DB communities were affected by season, N fertilization and moisture. Furthermore Bradyrhizobium and Burkholderia were the most prevalent genera in these three regions. This is the first study describing the dynamic of these bacteria in E. globulus plantations, and these data will likely contribute to a better understanding of the nutritional requirements of eucalypt cultivation and associated organic matter turnover.

  16. Contributions of a global network of tree diversity experiments to sustainable forest plantations

    OpenAIRE

    Verheyen, Kris; Vanhellemont, Margot; Auge, Harald; Baeten, Lander; Baraloto, Christopher; Barsoum, Nadia; Bilodeau-Gauthier, Simon; Bruelheide, Helge; Castagneyrol, Bastien; Godbold, Douglas; Haase, Josephine; Hector, Andy; Jactel, Hervé; Koricheva, Julia; LOREAU, Michel

    2016-01-01

    The area of forest plantations is increasing worldwide helping to meet timber demand and protect natural forests. However, with global change, monospecific plantations are increasingly vulnerable to abiotic and biotic disturbances. As an adaption measure we need to move to plantations that are more diverse in genotypes, species, and structure, with a design underpinned by science. TreeDivNet, a global network of tree diversity experiments, responds to this need by assessing the advantages and...

  17. State and Trend Analysis of Industrial Plantation Development in Foreign Countries

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The paper firstly reviewed industrial plantation development in the main forestry countries worldwide, and then summarized the state and trend of the R & D of industrial plantation in foreign countries in terms of genetic improvement, breeding techniques, site evaluation techniques, density control techniques, long-term productivity maintenance techniques and diseases and pests control techniques. In the meantime, the three management models employed in industrial plantations abroad was introduced, i.e. int...

  18. More Trees, More Poverty? The Socioeconomic Effects of Tree Plantations in Chile, 2001-2011.

    Science.gov (United States)

    Andersson, Krister; Lawrence, Duncan; Zavaleta, Jennifer; Guariguata, Manuel R

    2016-01-01

    Tree plantations play a controversial role in many nations' efforts to balance goals for economic development, ecological conservation, and social justice. This paper seeks to contribute to this debate by analyzing the socioeconomic impact of such plantations. We focus our study on Chile, a country that has experienced extraordinary growth of industrial tree plantations. Our analysis draws on a unique dataset with longitudinal observations collected in 180 municipal territories during 2001-2011. Employing panel data regression techniques, we find that growth in plantation area is associated with higher than average rates of poverty during this period.

  19. Mapping Deciduous Rubber Plantation Areas and Stand Ages with PALSAR and Landsat Images

    Directory of Open Access Journals (Sweden)

    Weili Kou

    2015-01-01

    Full Text Available Accurate and updated finer resolution maps of rubber plantations and stand ages are needed to understand and assess the impacts of rubber plantations on regional ecosystem processes. This study presented a simple method for mapping rubber plantation areas and their stand ages by integration of PALSAR 50-m mosaic images and multi-temporal Landsat TM/ETM+ images. The L-band PALSAR 50-m mosaic images were used to map forests (including both natural forests and rubber trees and non-forests. For those PALSAR-based forest pixels, we analyzed the multi-temporal Landsat TM/ETM+ images from 2000 to 2009. We first studied phenological signatures of deciduous rubber plantations (defoliation and foliation and natural forests through analysis of surface reflectance, Normal Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, and Land Surface Water Index (LSWI and generated a map of rubber plantations in 2009. We then analyzed phenological signatures of rubber plantations with different stand ages and generated a map, in 2009, of rubber plantation stand ages (≤5, 6–10, >10 years-old based on multi-temporal Landsat images. The resultant maps clearly illustrated how rubber plantations have expanded into the mountains in the study area over the years. The results in this study demonstrate the potential of integrating microwave (e.g., PALSAR and optical remote sensing in the characterization of rubber plantations and their expansion over time.

  20. More Trees, More Poverty? The Socioeconomic Effects of Tree Plantations in Chile, 2001-2011

    Science.gov (United States)

    Andersson, Krister; Lawrence, Duncan; Zavaleta, Jennifer; Guariguata, Manuel R.

    2016-01-01

    Tree plantations play a controversial role in many nations' efforts to balance goals for economic development, ecological conservation, and social justice. This paper seeks to contribute to this debate by analyzing the socioeconomic impact of such plantations. We focus our study on Chile, a country that has experienced extraordinary growth of industrial tree plantations. Our analysis draws on a unique dataset with longitudinal observations collected in 180 municipal territories during 2001-2011. Employing panel data regression techniques, we find that growth in plantation area is associated with higher than average rates of poverty during this period.

  1. Prospects of Applying Feed Processing Technologies Based on Industrial Plantation

    Directory of Open Access Journals (Sweden)

    Simon Petrus Ginting

    2012-06-01

    Full Text Available The potency of plantation sectors (palm oil, sugar cane and cacao as alternative feed resources for ruminants has been acknowledged since 20 – 25 years ago. However, the level of utilization of these feeds in small ruminant production system has been very low and sporadic. The typical chemical and physical characteristics of most of those feedstuffs required some steps of processing in order to improve their nutritional quality and to ease their handling. Small ruminants, like sheep and goats have relatively higher metabolic energy requirement per kg BW and anatomically have lower gut capacity to process lignocelluose materials compared to large ruminants. It is, therefore, these animals nutritionally face more constraints in handling lignocellulose and bulky materials mostly found in industrial by products or crop-residues from plantations. Physical processes (chopping, phyiscal separation, hydrothermal, chemical processes (ammoniation, hydrolyses and oxidative treatments and bio-conversions (fermentation, ensiling have been recommended as alternative technologies in maximizing the utilization of those feedstuffs for small ruminant animals. The principal mechanisms of those treatments are: (i breaking the linkages between structural carbohydrate and lignin so that it could be easily digested by the animal enzyme systems and (ii preserving the material from being spoilage due to its high moisture content or for feed stocking purposes. Priorities for choosing the most effective processing technology for implementation or adoption is depent largely on the scale of feed production. Ammoniation, chopping, physical separation, ensiling or bio-conversion are several technologies mostly recommended for small scale operation in situ. These alternative technologies should be able to be adopted by small-holders living around the plantation area. The commercial or large scale feed production could be implemented by the plantation industry by giving high

  2. 训练剂-1工艺过程的Aspen Plus全流程模拟%Simulation of the whole production process of training agent-1 using Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    盖希杰; 邓德茹; 刘兴红; 王志甄

    2010-01-01

    建立了训练剂-1间歇工艺过程的数学模型,利用流程模拟软件Aspen Plus内置的物性资源、物性估算和实验数据回归的方法,弥补了实验数据的不足.以工艺过程机理和间歇过程数学模型为基础,采用Aspen Plus软件对训练剂-1间歇工艺过程全流程进行了模拟,模拟结果与实际工艺系统运行情况吻合良好.

  3. Aspen Plus在制药化工原理汽液平衡教学中的应用%Applications of Aspen Plus in the Vapor-liquid Equilibrium Teaching of Pharmaceutical and Chemical Engineering Principles

    Institute of Scientific and Technical Information of China (English)

    王贤书

    2011-01-01

    介绍了Aspen Plus化工流程模拟软件的一般使用方法,结合本人在山苍子油蒸馏分离模拟计算方面的科研成果,探讨了Aspen Plus软件在《制药化工原理》汽液平衡教学中的应用.实践表明,采用流程模拟软件辅助制药化工原理教学的方法,不仅有助于培养学生的兴趣和拓宽学生的视野,使学生加深了对汽液平衡内容的深刻理解,而且有助于培养学生利用流程模拟技术解决工程实际问题的能力.

  4. 基于 Aspen Plus 软件的磨煤干燥过程模拟与分析%Simulation and Analyzsis of the Coal Grinding and Drying Process with the Aspen Plus Software

    Institute of Scientific and Technical Information of China (English)

    周春平; 甘丹; 严应群

    2014-01-01

    After simulating and analyzing the coal grinding and drying process with the Aspen Plus software ,know accurately the utilities consumption which including the fuel gas ,low pressure nitrogen gas ,combustion air ,dilution air and electricity ,etc . Optimizing the drying process could provide guidance for the engineering design and manufacturing operation .%运用Aspen Plus软件对磨煤干燥过程进行模拟与分析,可以比较准确地知道CMD工段的燃料气、低低压氮气、助燃空气、稀释空气、电力等公用工程的消耗,优化干燥工艺流程,为工程设计和生产操作提供指导。

  5. Continuous Extraction and Separation Based on Aspen for the Water of the ISO-Propylene Alcohol-Water%基于Aspen plus异丙醚-异丙醇-水的连续萃取分离

    Institute of Scientific and Technical Information of China (English)

    战俊磊

    2015-01-01

    选用乙二醇(EG)为萃取剂,用Aspen Plus化工模拟软件中的Radfrac单元操作模块,采用UNIFAC物性计算方法,通过优化各参数,在适宜操作条件下,塔顶可以得到高纯度的二异丙醚、异丙醇产品.

  6. Application of ASPEN PLUS Chemical Modeling System in the Process of Fractionation%ASPEN PLUS化工模拟系统在精馏过程中的应用

    Institute of Scientific and Technical Information of China (English)

    刘雨虹

    2003-01-01

    应用ASPEN PLUS化工模拟系统中的RateFrac精馏模块对催化裂化气分工艺中的精馏塔进行模拟,模拟结果与装置原始设计结果吻合,可用于指导生产,并提供装置改造依据.

  7. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  8. 化工设计中流程模拟软件Aspen Plus的使用

    Institute of Scientific and Technical Information of China (English)

    彭江

    2015-01-01

    化工设计流程模拟软件是一款集化工设计、动态模拟以及各类计算于一体的极其强大的功能性软件。Aspen Plus在化工设计过程中得到普遍的应用,极大提升了我国化工领域工艺流程等方面的设计效率和水平。为此,本文就以A spen Plus软件的特点和优势进行介绍,并详细说明Aspen Plus在化工设计领域中突出的表现和运用的具体方法。

  9. One-Dimensional Biomass Fast Pyrolysis Model with Reaction Kinetics Integrated in an Aspen Plus Biorefinery Process Model

    Energy Technology Data Exchange (ETDEWEB)

    Humbird, David; Trendewicz, Anna; Braun, Robert; Dutta, Abhijit

    2017-01-27

    A biomass fast pyrolysis reactor model with detailed reaction kinetics and one-dimensional fluid dynamics was implemented in an equation-oriented modeling environment (Aspen Custom Modeler). Portions of this work were detailed in previous publications; further modifications have been made here to improve stability and reduce execution time of the model to make it compatible for use in large process flowsheets. The detailed reactor model was integrated into a larger process simulation in Aspen Plus and was stable for different feedstocks over a range of reactor temperatures. Sample results are presented that indicate general agreement with experimental results, but with higher gas losses caused by stripping of the bio-oil by the fluidizing gas in the simulated absorber/condenser. This integrated modeling approach can be extended to other well-defined, predictive reactor models for fast pyrolysis, catalytic fast pyrolysis, as well as other processes.

  10. Implications of Elevated Atmospheric Carbon Dioxide and Tropospheric Ozone for Water Use in Stands of Trembling Aspen and Paper Birch

    Science.gov (United States)

    Rhea, Lee Kirk

    Projected increases in the atmospheric concentration of CO2 and tropospheric O3 over the next 50 years are of concern due in part to their potential to affect forest water budgets. I conducted a series of studies at the Aspen Free Air CO2 and O3 Enrichment experiment near Rhinelander, WI to determine the effect of projected concentrations of these gases for the year 2050 on the water budget in stands of trembling aspen and paper birch. In order to determine the effects of elevated CO2 (eCO 2) and O3 (eO3) on rainfall partitioning between interception, through fall, and stem flow I performed a computerized analysis of photographed canopy branches and compared the results to hydrologic measurements. Elevated O3 significantly decreased total aspen and birch branch length, resulting in net decreases for 2002 whorls of -18 % and 2006 whorls of -16 %. Some of these changes had measurable effects on rainfall partitioning. The biomass of fine roots has been observed to change in response to eCO2 and eO3 at shallow depths, but little work has been done to assess deeper roots. I characterized fine root responses to eCO 2 and eO3 to a depth of one meter. Fumigation with O 3 increased small root biomass in shallow soil 30 % in all aspen plots and decreased root biomass in shallow soil 46 % in aspen-birch plots. Increases in root length up to 131 % and specific root length up to 77 % occurred under eO3 in middle and deep soil layers, indicating more extensive soil exploration at depth. Small root biomass in shallow soils increased 20 % to 24 % under eCO2, indicative of more intensive soil exploration near the surface. Previous studies of sapwood from Aspen-FACE indicated that anatomical structures related to hydraulic conductance (K) differed between aspen clones and that they responded to the treatments differently. I constructed embolism curves for stem wood samples collected below the base of the live crowns. There were no significant treatment effects on K at full water

  11. Fertilization effects on forest carbon storage and exchange, and net primary production: A new hybrid process model for stand management

    Science.gov (United States)

    D. A. Sampson; R. H. Waring; C. A. Maier; C. M. Gough; M. J. Ducey; K. H. Johnsen

    2006-01-01

    A critical ecological question in plantation management is whether fertilization, which generally increases yield, results in enhanced C sequestration over short rotations. We present a rotation-length hybrid process model (SECRETS-3PG) that was calibrated (using control treatments; CW) and verified (using fertilized treatments; FW) using daily estimates of H

  12. Characterization of SP1, a Stress-Responsive, Boiling-Soluble, Homo-Oligomeric Protein from Aspen1

    Science.gov (United States)

    Wang, Wang-Xia; Pelah, Dan; Alergand, Tal; Shoseyov, Oded; Altman, Arie

    2002-01-01

    sp1 cDNA was isolated from aspen (Populus tremula) plants by immunoscreening an expression library using polyclonal antibodies against BspA protein. BspA, which is a boiling-stable protein, accumulates in aspen plants in response to water stress and abscisic acid application (Pelah et al., 1995). The sp1 cDNA was found to encode a 12.4-kD generally hydrophilic protein with a hydrophobic C terminus, which is different from the BspA protein and was termed SP1 (stable protein 1). Northern-blot analysis revealed that sp1 encodes a small mRNA (about 0.6 kb) that is expressed in aspen plants under non-stress conditions and is accumulated after salt, cold, heat, and desiccation stress, and during the recovery from stress. The SP1 detected in plants remained soluble upon boiling, migrated both as a 12.4-kD band and a much higher mass of 116 kD on a 17% (w/v) Tricine-sodium dodecyl sulfate-polyacrylamide gel. Comparative protease digestion patterns, amino acid analyses, and the N-terminal sequences of the 12.4- and 116-kD proteins revealed that SP1 is homo-oligomeric. Furthermore, gel filtration chromatography analysis indicated that SP1 exists in aspen plants as a complex, composed of 12 subunits of 12.4 kD. A large number of sequences deduced from expressed sequence tags and genomic sequences of other organisms with unknown function show high homology to SP1. Thus, SP1 may represent a new protein family. Here, we present the first report on this putative protein family: the cloning, isolation, and characterization of SP1, a stress-responsive, boiling-soluble, oligomeric protein. PMID:12376651

  13. Aspen InfoPlus.21实时数据库管理系统的应用

    Institute of Scientific and Technical Information of China (English)

    肖建荣; 万慧芸

    2013-01-01

    To meet the requirement of chemical plant information management, Aspen Infoplus.21 real-time database manage-ment system is constructed based on the current DCS, LIMS and company office LAN. With this network, DCS plant operation re-al-time data information is acquired, monitored and used directly via OPC interface, DCS batch information is acquired, monitored and used directly via Aspen Production Record Manager and Microsoft SQL Server, LIMS data is acquired, monitored and used di-rectly via ODBC interface, and the open framework is developed. With these excellent applications, we have achieved our high work efficiency, and have eventually improved our plant operation effectiveness.%  针对化工厂信息管理的需要,在现有DCS、LIMS和公司局域网(LAN)基础上,搭建Aspen Infoplus.21实时数据库管理系统,通过OPC接口实时读取、监控、查阅和应用DCS系统数据,通过Aspen Production Record Manag-er及Microsoft SQL Server直接抽取DCS工厂批量工艺批次信息,通过ODBC接口及时读取实验室LIMS产品化验数据,并支持开放框架运用。通过实际应用,提高工作效率,最终提高整个工厂生产运作的有效性。

  14. Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level

    National Research Council Canada - National Science Library

    Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

    2016-01-01

    ...) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground...

  15. Replanting/underplanting strategy for old coconut plantations in Papua New Guinea

    Directory of Open Access Journals (Sweden)

    Ollivier Jean

    2001-11-01

    Full Text Available In most producing countries, the population of coconut palms is growing old, and ways of replacing them are rarely implemented to ensure that production is maintained and the future of the industry and its profitability are safeguarded. Rehabilitating/replanting coconut plantations and adopting appropriate intercropping systems is one of the main challenges to be taken up for the future of coconut in the Asia-Pacific region. The example of Papua New Guinea (PNG reveals one of the lowest yields per hectare among the countries in the Asia-Pacific zone. Almost 106,000 ha were planted between 1910 and 1940, amounting to around 40% of the current coconut plantings, hence 80 to 100,000 ha can be expected to disappear in the next twenty years. Faced with this forecast, the PNG Cocoa and Coconut Research Institute (PNG CCRI launched several operations, beginning with the creation of a coconut research centre on the PNG mainland: examination of a replanting strategy for old coconut plantings, based on hybrid planting material, distribution of improved planting material through the creation of a seed garden, and development of a system for controlling pest populations in high-risk zones. The experiments set up at the station are designed to optimize the felling date for old coconut palms, by measuring the effects of competition with the underplanted hybrids, and to determine from an economic point of view the best strategy to be applied for implementing rehabilitation and/or replanting programmes in old coconut plantings. This paper describes the results of these operations.

  16. Hydraulic conductivity and aquaporin transcription in roots of trembling aspen (Populus tremuloides) seedlings colonized by Laccaria bicolor.

    Science.gov (United States)

    Xu, Hao; Cooke, Janice E K; Kemppainen, Minna; Pardo, Alejandro G; Zwiazek, Janusz J

    2016-07-01

    Ectomycorrhizal fungi have been reported to increase root hydraulic conductivity (L pr) by altering apoplastic and plasma membrane intrinsic protein (PIP)-mediated cell-to-cell water transport pathways in associated roots, or to have little effect on root water transport, depending on the interacting species and imposed stresses. In this study, we investigated the water transport properties and PIP transcription in roots of aspen (Populus tremuloides) seedlings colonized by the wild-type strain of Laccaria bicolor and by strains overexpressing a major fungal water-transporting aquaporin JQ585595. Inoculation of aspen seedlings with L. bicolor resulted in about 30 % colonization rate of root tips, which developed dense mantle and the Hartig net that was restricted in the modified root epidermis. Transcript abundance of the aspen aquaporins PIP1;2, PIP2;1, and PIP2;2 decreased in colonized root tips. Root colonization by JQ585595-overexpressing strains had no significant impact on seedling shoot water potentials, gas exchange, or dry mass; however, it led to further decrease in transcript abundance of PIP1;2 and PIP2;3 and the significantly lower L pr than in non-inoculated roots. These results, taken together with our previous study that showed enhanced root water hydraulics of L. bicolor-colonized white spruce (Picea glauca), suggest that the impact of L. bicolor on root hydraulics varies by the ectomycorrhiza-associated tree species.

  17. Comparative simulation study of gas-phase propylene polymerization in fluidized bed reactors using aspen polymers and two phase models

    Directory of Open Access Journals (Sweden)

    Shamiria Ahmad

    2013-01-01

    Full Text Available A comparative study describing gas-phase propylene polymerization in fluidized-bed reactors using Ziegler-Natta catalyst is presented. The reactor behavior was explained using a two-phase model (which is based on principles of fluidization as well as simulation using the Aspen Polymers process simulator. The two-phase reactor model accounts for the emulsion and bubble phases which contain different portions of catalysts with the polymerization occurring in both phases. Both models predict production rate, molecular weight, polydispersity index (PDI and melt flow index (MFI of the polymer. We used both models to investigate the effect of important polymerization parameters, namely catalyst feed rate and hydrogen concentration, on the product polypropylene properties, such as production rate, molecular weight, PDI and MFI. Both the two-phase model and Aspen Polymers simulator showed good agreement in terms of production rate. However, the models differed in their predictions for weight-average molecular weight, PDI and MFI. Based on these results, we propose incorporating the missing hydrodynamic effects into Aspen Polymers to provide a more realistic understanding of the phenomena encountered in fluidized bed reactors for polyolefin production.

  18. Effectiveness of mycorrhizal inoculation in the nursery on root colonization, growth, and nutrient uptake of aspen and balsam poplar

    Energy Technology Data Exchange (ETDEWEB)

    Quoreshi, A.M.; Khasa, D.P. [Symbiotech Research Inc. 201, 509-11 Avenue, Nisku, AB (Canada); Forest Biology Research Centre, University of Laval, Quebec (Canada)

    2008-05-15

    Aspen and balsam poplar seedlings were inoculated with six species of ectomycorrhizal fungi (Hebeloma longicaudum, Laccaria bicolor, Paxillus involutus, Pisolithus tinctorius, Rhizopogon vinicolor, and Suillus tomentosus), one species of endomycorrhizal fungus (Glomus intraradices), two species of bacteria (Agrobacterium sp. and Burkholderia cepacia), treated with a growth hormone (SR3), and co-inoculated with a combination of Paxillus and Burkholderia. The seedlings were grown in a greenhouse under three different fertility regimes. Bacterial inoculation alone did not affect seedling growth and nutrition as observed when co-inoculated with ectomycorrhizal fungus. The biomass and root collar diameter of aspen and balsam poplar were significantly increased when adequate mycorrhizas are formed and more prominent when co-inoculated with P. involutus and B. cepacia and grown at the 67% fertilizer level. Except for R. vinicolor and S. tomentosus, the other four species of ectomycorrhizal fungi and G. intraradices formed symbiotic associations with both plant species. Both ectomycorrhizal and endomycorrhizal colonization were observed at all fertilizer levels and fertilizer applications did not affect the colonization rates. Nitrogen and phosphorus concentrations were significantly improved in both aspen and balsam poplar compared with control only when co-inoculated with P. involutus and B. cepacia. However, plant net nitrogen uptake (content) increased significantly in all successful inoculation treatments and co-inoculated treatment when compared with control. These results hold promise for incorporation of inoculation of Populus sp. with appropriate mycorrhizal fungi and selected bacteria into commercial nursery system to improve the establishment of Populus in various sites. (author)

  19. Behavioral archives link the chemistry and clonal structure of trembling aspen to the food choice of North American porcupine.

    Science.gov (United States)

    Diner, Brandee; Berteaux, Dominique; Fyles, Jim; Lindroth, Richard L

    2009-07-01

    Understanding the links among plant genotype, plant chemistry, and food selection by vertebrate herbivores is critical to assess the role of herbivores in the evolution of plant secondary chemistry. Some specialized vertebrate herbivores have been shown to select plants differentially according to plant genotype, but examples from generalists, which constitute the vast majority of vertebrate herbivores, are few, especially in natural conditions. We examined the relationship between the North American porcupine (Erethizon dorsatum), a generalist mammalian herbivore, and clonal trembling aspen (Populus tremuloides), a preferred food source of porcupines. We determined preference for certain aspen trees through visual examination of porcupine climbing scars left on tree bark, and through a controlled feeding experiment. We used genetic and biochemical analyses to link the behavioral archives (climbing scars) left by porcupines on aspen trunks to the clonal structure and chemical composition of trees. We show that two phenolic glycosides (tremulacin and salicortin), which are under a high degree of genetic control and thus vary in concentration across clones, are the chemical variables that most influence (deter) feeding choices by porcupines. Using behavioral archives left by a wild herbivore on a natural stand of plants thus allowed us to demonstrate that a generalist vertebrate herbivore can choose plants according to their clonal structure and genetically based chemical composition. Our results contribute to extending previous findings obtained with generalist herbivores studied in controlled conditions, and with specialist herbivores studied in the field.

  20. Stand age characteristics and soil properties affect species composition of vascular plants in short rotation coppice plantations

    OpenAIRE

    Sarah Baum; Martin Weih; Andreas Bolte

    2012-01-01

    Woody biomass plantations on agricultural sites are an attractive source of biomass for bioenergy, but their effects on local biodiversity are unclear. This study’s objective was to evaluate the influences of light availability, plantation age, and soil properties on phytodiversity in short rotation coppice (SRC) plantations. Ground vegetation mapping, irradiance measurement (PAR), and surface soil analyses were conducted in 15 willow and poplar SRC plantations in Central Sweden a...