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

Highly Efficient Release of Glycopeptides from Hydrazide Beads by Hydroxylamine Assisted PNGase F Deglycosylation for N-Glycoproteome Analysis.

Science.gov (United States)

Huang, Junfeng; Wan, Hao; Yao, Yating; Li, Jinan; Cheng, Kai; Mao, Jiawei; Chen, Jin; Wang, Yan; Qin, Hongqiang; Zhang, Weibing; Ye, Mingliang; Zou, Hanfa

2015-10-20

Selective enrichment of glycopeptides from complex sample followed by cleavage of N-glycans by PNGase F to expose an easily detectable mark on the former glycosylation sites has become the popular protocol for comprehensive glycoproteome analysis. On account of the high enrichment specificity, hydrazide chemistry based solid-phase extraction of N-linked glycopeptides technique has sparked numerous interests. However, the enzymatic release of glycopeptides captured by hydrazide beads through direct incubation of the beads with PNGase F is not efficient due to the inherent steric hindrance effect. In this study, we developed a hydroxylamine assisted PNGase F deglycosylation (HAPD) method using the hydroxylamine to release glycopeptides captured on the hydrazide beads through the cleavage of hydrazone bonds by transamination followed with the PNGase F deglycosylation of the released glycopeptides in the free solution. Because of the homogeneous condition for the deglycosylation, the recovery of deglycosylated peptides (deglycopeptides) was improved significantly. It was found that 27% more N-glycosylation sites were identified by the HAPD strategy compared with the conventional method. Moreover, the ratio of identified N-terminal glycosylated peptides was improved over 5-fold.

Functional studies of human intestinal alkaline sphingomyelinase by deglycosylation and mutagenesis

DEFF Research Database (Denmark)

Wu, Jun; Hansen, Gert H; Nilsson, Ake

2005-01-01

in NPP are conserved, and those of the active core are modified. We examined the functional changes of the enzyme induced by deglycosylation and mutagenesis. Treating alk-SMase cDNA-transfected COS-7 cells with tunicamycin rendered the expressed enzyme completely inactive. Mutations of the five potential...

Volatile-Mediated within-Plant Signaling in Hybrid Aspen: Required for Systemic Responses.

Science.gov (United States)

Li, Tao; Blande, James D

2017-04-01

Plant volatiles play crucial roles in signaling between plants and their associated community members, but their role in within-plant signaling remains largely unexplored, particularly under field conditions. Using a system comprising the hybrid aspen (Populus tremula x tremuloides) and the specialized herbivorous leaf beetle (Phratora laticollis) and, combining field, greenhouse and laboratory experiments, we examined whether local damage triggered systemic responses in undamaged branches that lack vascular connection to the damaged branches, and to what extent this was caused by airborne volatile signals versus internal signals. An experiment tracing dye through the vasculature of saplings revealed no downward movement of the dye from upper to lower branches, suggesting a lack of vascular connectivity among branches. However, we found under both field and laboratory conditions that herbivore feeding on upper branches elicited volatile emissions by undamaged lower branches. Greenhouse experiments manipulating air contact between damaged and undamaged branches showed that systemic induction of volatiles was almost eliminated when air contact was interrupted. Our findings clearly demonstrate that herbivore-induced volatiles overcome vascular constraints and mediate within-plant signaling. Further, we found that volatile signaling led to induction of different classes of volatiles under field and environment controlled conditions, with a weaker response observed in the field. This difference not only reflects the dose- and time-dependent nature of volatile signaling, but also points out that future studies should focus more on field observations to better understand the ecological role of volatile-mediated within-plant signaling.

Repeated Prescribed Burning in Aspen

Science.gov (United States)

Donald A. Perala

1974-01-01

Infrequent burning weather, low flammability of the aspen-hardwood association, and prolific sprouting and seeding of shrubs and hardwoods made repeated dormant season burning a poor tool to convert good site aspen to conifers. Repeat fall burns for wildlife habitat maintenance is workable if species composition changes are not important.

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...

Manipulations to regenerate aspen ecosystems

Science.gov (United States)

Wayne D. Shepperd

2001-01-01

Vegetative regeneration of aspen can be initiated through manipulations that provide hormonal stimulation, proper growth environment, and sucker protection - the three elements of the aspen regeneration triangle. The correct course of action depends upon a careful evaluation of the size, vigor, age, and successional status of the existing clone. Soils and site...

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

Decay of aspen in Colorado

Science.gov (United States)

Ross W. Davidson; Thomas E. Hinds; Frank G. Hawksworth

1959-01-01

Quaking aspen (Populus tremuloides Michx.) stands are extensive in the central Rocky Mountains. The species reaches its maximum development in the mountains and high mesas west of the Continental Divide in Colorado (Baker, 1925). On the better sites aspen yields a greater volume of wood in a shorter period than most of the conifers growing at comparable elevations. The...

A modified spectrophotometric assay to estimate deglycosylation of steroidal saponin to sapogenin by mixed ruminal microbes.

Science.gov (United States)

Wang, Yuxi; McAllister, Tim A

2010-08-30

The lack of a method for measuring deglycosylation of saponins in ruminal fluid has limited the ability to investigate the impact of these compounds on rumen microorganisms. A simple spectrophotometric assay was adapted and a protocol developed to enable measurement of steroidal saponin and sapogenin in ruminal fluid. The procedure was used for in vitro determination of deglycosylation activity of rumen bacteria obtained from cattle fed or not fed Yucca schidigera saponin, and to determine the relative deglycosylase activities of extracellular and cell-associated enzymes from ruminal content. Modifications to the spectrophotometric assay (i.e. heating time shortened to 10 min and 0.5 mL dH(2)O added to the reaction mixture) improved the stability of the optical density (425 nm) of the chromophore for up to 24 h post-reaction. Centrifugation (12 000 x g, 20 min) enabled differential estimations of steroidal saponin and sapogenin in ruminal fluid. Steroidal saponin added to defaunated ruminal fluid (dRF) or clarified ruminal fluid (cRF) was recovered completely from the mixture as saponin + sapogenin (99.1% and 100.6%, respectively), whereas saponin recovery from the supernatant of dRF was greatly reduced (P ruminal extracellular enzyme preparation was recoverable in supernatant after 24 h, compared with only 26-32% remaining in supernatant from incubation with a cell-associated enzymes fraction. Mixed rumen bacteria deglycosylate steroidal saponin to sapogenin, at activity levels unaffected by prior exposure to saponin, but they were unable to degrade the sapogenin core structure. Deglycosylation activity occurred primarily in the cell-associated enzyme fraction of ruminal content. Copyright (c) 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.

Can aspen persist in conifer dominated forests?

Science.gov (United States)

Douglas H. Page; John D. Shaw

2016-01-01

In 1998 we measured a large, old aspen in a mixed spruce-fir-aspen forest on the Utah State University T.W. Daniel Experimental Forest in northern Utah. The tree was 297 years old - about the same age as the oldest spruce in the stand. A search of the forestry literature revealed that the oldest published age for an aspen came from a tree in the Sierra Nevada Range in...

Aspen Delineation - Inyo National Forest [ds366

Data.gov (United States)

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

Aspen Delineation - Klamath National Forest [ds370

Data.gov (United States)

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

Aspen Delineation - Sierra State Parks [ds380

Data.gov (United States)

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

Aspen Delineation - Sequoia National Forest [ds378

Data.gov (United States)

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

Aspen Delineation - Lassen National Forest [ds372

Data.gov (United States)

California Natural Resource Agency — 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...

Implementing ASPEN on the CRAY computer

International Nuclear Information System (INIS)

Duerre, K.H.; Bumb, A.C.

1981-01-01

This paper describes our experience in converting the ASPEN program for use on our CRAY computers at the Los Alamos National Laboratory. The CRAY computer is two-to-five times faster than a CDC-7600 for scalar operations, is equipped with up to two million words of high-speed storage, and has vector processing capability. Thus, the CRAY is a natural candidate for programs that are the size and complexity of ASPEN. Our approach to converting ASPEN and the conversion problems are discussed, including our plans for optimizing the program. Comparisons of run times for test problems between the CRAY and IBM 370 computer versions are presented

AspenTech shows specific tools for refiners; AspenTech deploie des outils specifiques pour les raffineurs

Energy Technology Data Exchange (ETDEWEB)

Legros, E

2003-10-01

The supplier of integrated softwares AspenTech has organized last May, the 7 in Gelsenkirchen, on the site of the Veba Oel refinery, a seminar 'refining' intended to show the specificities of its products: Hysys, Aspen Utilities, Icarus...About fifty German engineers and responsible persons coming from refining and engineering firms have participated to this studies day. (O.M.)

Aspen Delineation - Klamath National Forest, EUI [ds368

Data.gov (United States)

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

Aspen Delineation - Plumas National Forest, FRRD [ds376

Data.gov (United States)

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

Evaluation of burned aspen communities in Jackson Hole, Wyoming

Science.gov (United States)

Charles E. Kay

2001-01-01

Aspen has been declining in Jackson Hole for many years, a condition generally attributed to the fact that lightning fires have been aggressively suppressed since the early 1900s. It is also believed that burning will successfully regenerate aspen stands despite high elk numbers. To test this hypothesis, I evaluated 467 burned and 495 adjacent, unburned aspen stands at...

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.

N-Linked Deglycosylated Melanopsin Retains Its Responsiveness to Light

DEFF Research Database (Denmark)

Fahrenkrug, J.; Falktoft, B.; Georg, B.

2009-01-01

sites. Immunoblotting for membrane-bound melanopsin from the PC12 cells transfected to express wild-type melanopsin disclosed two immunoreactive bands of 62 and 49 kDa. Removal of N-linked glycosylation by tunicamycin or PNGase F changed the 62 kDa band to a 55 kDa band, while the 49 kDa band......-glycosidase and neuraminidase converted the 55 kDa band to a 49 kDa band. Finally, neither in vivo N-linked deglycosylation nor mutations of the two N-linked glycosylation sites significantly affected melanopsin function measured by Fos induction after light stimulation. In conclusion, we have shown that heterologously...

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...

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

ASPEN simulation of cogeneration plants

Energy Technology Data Exchange (ETDEWEB)

Ligang Zheng [CANMET Energy Technology Center, Natural Resources Canada, Nepean, ONT (Canada); Furimsky, E. [IMAG Group, Ottawa, ONT (Canada)

2003-07-01

A detailed flow sheet of the combined cycle cogeneration plant fuelled by natural gas was prepared. The model for simulation of this plant was developed using the ASPEN PLUS software. The results generated using this model were compared with the operating data of the commercial plant generating about 43.6 MW of electricity by gas turbine and 28.6 MW of electricity by steam turbine. The electricity is supplied to the grid, whereas the low pressure steam is utilised locally for heating purposes. The key data generated using the ASPEN model are in good agreement with the operating data. (author)

ASPEN simulation of cogeneration plants

Energy Technology Data Exchange (ETDEWEB)

Zheng Ligang E-mail: lzheng@nrcan.gc.ca; Furimsky, Edward

2003-07-01

A detailed flow sheet of the combined cycle cogeneration plant fuelled by natural gas was prepared. The model for simulation of this plant was developed using the ASPEN PLUS software. The results generated using this model were compared with the operating data of the commercial plant generating about 43.6 MW of electricity by gas turbine and 28.6 MW of electricity by steam turbine. The electricity is supplied to the grid, whereas the low pressure steam is utilised locally for heating purposes. The key data generated using the ASPEN model are in good agreement with the operating data.

ASPEN simulation of cogeneration plants

International Nuclear Information System (INIS)

Zheng Ligang; Furimsky, Edward

2003-01-01

A detailed flow sheet of the combined cycle cogeneration plant fuelled by natural gas was prepared. The model for simulation of this plant was developed using the ASPEN PLUS software. The results generated using this model were compared with the operating data of the commercial plant generating about 43.6 MW of electricity by gas turbine and 28.6 MW of electricity by steam turbine. The electricity is supplied to the grid, whereas the low pressure steam is utilised locally for heating purposes. The key data generated using the ASPEN model are in good agreement with the operating data

Deglycosylation systematically improves N-glycoprotein identification in liquid chromatography-tandem mass spectrometry proteomics for analysis of cell wall stress responses in Saccharomyces cerevisiae lacking Alg3p.

Science.gov (United States)

Bailey, Ulla-Maja; Schulz, Benjamin L

2013-04-01

Post-translational modification of proteins with glycosylation is of key importance in many biological systems in eukaryotes, influencing fundamental biological processes and regulating protein function. Changes in glycosylation are therefore of interest in understanding these processes and are also useful as clinical biomarkers of disease. The presence of glycosylation can also inhibit protease digestion and lower the quality and confidence of protein identification by mass spectrometry. While deglycosylation can improve the efficiency of subsequent protease digest and increase protein coverage, this step is often excluded from proteomic workflows. Here, we performed a systematic analysis that showed that deglycosylation with peptide-N-glycosidase F (PNGase F) prior to protease digestion with AspN or trypsin improved the quality of identification of the yeast cell wall proteome. The improvement in the confidence of identification of glycoproteins following PNGase F deglycosylation correlated with a higher density of glycosylation sites. Optimal identification across the proteome was achieved with PNGase F deglycosylation and complementary proteolysis with either AspN or trypsin. We used this combination of deglycosylation and complementary protease digest to identify changes in the yeast cell wall proteome caused by lack of the Alg3p protein, a key component of the biosynthetic pathway of protein N-glycosylation. The cell wall of yeast lacking Alg3p showed specifically increased levels of Cis3p, a protein important for cell wall integrity. Our results showed that deglycosylation prior to protease digestion improved the quality of proteomic analyses even if protein glycosylation is not of direct relevance to the study at hand. Copyright © 2013 Elsevier B.V. All rights reserved.

Iterative Repair Planning for Spacecraft Operations Using the Aspen System

Science.gov (United States)

Rabideau, G.; Knight, R.; Chien, S.; Fukunaga, A.; Govindjee, A.

2000-01-01

This paper describes the Automated Scheduling and Planning Environment (ASPEN). ASPEN encodes complex spacecraft knowledge of operability constraints, flight rules, spacecraft hardware, science experiments and operations procedures to allow for automated generation of low level spacecraft sequences. Using a technique called iterative repair, ASPEN classifies constraint violations (i.e., conflicts) and attempts to repair each by performing a planning or scheduling operation. It must reason about which conflict to resolve first and what repair method to try for the given conflict. ASPEN is currently being utilized in the development of automated planner/scheduler systems for several spacecraft, including the UFO-1 naval communications satellite and the Citizen Explorer (CX1) satellite, as well as for planetary rover operations and antenna ground systems automation. This paper focuses on the algorithm and search strategies employed by ASPEN to resolve spacecraft operations constraints, as well as the data structures for representing these constraints.

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

Modeling, design and analysis of a stand-alone hybrid power generation system using solar/urine

International Nuclear Information System (INIS)

Wu, Wei; Zhou, Ya-Yan; Lin, Mu-Hsuan; Hwang, Jenn-Jiang

2013-01-01

Highlights: • The stand-alone hybrid power system is presented. • The urine-to-hydrogen processor is proposed. • Scenario analysis of the hybrid power dispatching and the urine/solar demands is investigated. • The design, modeling and optimization of the hybrid power system is addressed by Aspen Plus and Matlab. - Abstract: The urine turned to hydrogen as an energy conversion process is integrated into a stand-alone hybrid (PV/FC/battery) power generation system. The optimization and simulation of a new urine-to-hydrogen processor is evaluated in Aspen Plus environment. In our approach, the PV generator aims to reduce urine consumption and the lithium-ion battery can compensate the power gap due to the fuel processing delay. Based on prescribed patterns of solar irradiation and the daily load demand of a 30-persons classroom, scenario analyses of the hybrid power dispatching and operational feasibility is addressed

Aspen in the Sierra Nevada: Regional conservation of a continental species

Science.gov (United States)

Paul C. Rogers; Wayne D. Shepperd; Dale L. Bartos

2007-01-01

Quaking aspen (Populus tremuloides Michx.) a common species in North America, is a minor species in the Sierra Nevada of California. However, the limited coverage of aspen in this area appears to carry a disproportionate biodiversity load: numerous species are dependent on the unique components of aspen forests habitat. Land managers in the region...

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

Simulation of quaking aspen potential fire behavior in Northern Utah, USA

Science.gov (United States)

R. Justin DeRose; A. Joshua Leffler

2014-01-01

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...

Characteristics of aspen infected with heartrot: Implications for cavity-nesting birds

Science.gov (United States)

Chris Witt

2010-01-01

Phellinus tremulae is an important fungal decay agent common to aspen and a critical component to the cavity-nesting bird complex found in western aspen stands. Little information exists on the conditions that facilitate infection and spread of P. tremulae in aspen forests. I used Forest Inventory and Analysis (FIA) data to explore the relationships of several tree and...

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.

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.

Regio-selective deglycosylation of icariin by cell suspension cultures of Glycyrrhiza uralensis and Morus alba.

Science.gov (United States)

Zhang, De-Wu; Tao, Xiao-Yu; Chen, Ri-Dao; Yu, Li-Yan; Dai, Jun-Gui

2015-01-01

Biotransformations of icariin (1) by cell suspension cultures of Glycyrrhiza uralensis and Morus alba yielded two new metabolites, icaruralins A and B (2 and 3), and one known metabolite, baohuoside I (4). Their structures were determined on the basis of extensive spectroscopic analysis. This is the first report that the cell suspension cultures of G. uralensis and M. alba possess deglycosylation functionality.

Molecular tools and aspen management: A primer and prospectus

Science.gov (United States)

Karen E. Mock; Bryce A. Richardson; Paul G. Wolf

2013-01-01

Aspen (Populus tremuloides) isaniconic species in North American landscapes, highly valued for recreation, fiber, wildlife and livestock forage, carbon sequestration, biodiversity, and as a fuelbreak. However, there are rising concerns about the ability of aspen to persist in portions of its range, based on bioclimatic modeling, physiological thresholds and mortality...

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

Science.gov (United States)

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 (σ sap ), 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 (K wb ), leaf blade (K lb ) and petiole hydraulic conductances (K P ) showed clear daily dynamics. Air temperature (T A ) and photosynthetic photon flux density (PPFD), but also water vapour pressure deficit (VPD) and relative humidity (RH), had significant impacts on K wb K lb , K P , [K + ] and σ sap . Osm varied only with light intensity, while K B varied depending on atmospheric evaporative demand expressed as T A , VPD or RH. Xylem sap pH depended inversely on soil water potential (Ψ S ) and during daylight also on VPD. Although soil water content was close to saturation during the study period, Ψ S influenced also [K + ] and σ sap . 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.

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 (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.

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.

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

International Nuclear Information System (INIS)

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

2010-01-01

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 deg. 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. - We report that elevated CO 2 confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.

Adverse Influence of Radio Frequency Background on Trembling Aspen Seedlings: Preliminary Observations

Directory of Open Access Journals (Sweden)

Katie Haggerty

2010-01-01

Full Text Available Numerous incidents of aspen decline have been recorded in North America over the past half century, and incidents of very rapid mortality of aspen clones have been observed in Colorado since 2004. The radio frequency (RF environment of the earth has undergone major changes in the past two centuries due to the development and use of electricity in power and communications applications, and the anthropogenic RF background continues to increase in intensity and complexity. This study suggests that the RF background may have strong adverse effects on growth rate and fall anthocyanin production in aspen, and may be an underlying factor in aspen decline.

Increased biological activity of deglycosylated recombinant human granulocyte/macrophage colony-stimulating factor produced by yeast or animal cells

International Nuclear Information System (INIS)

Moonen, P.; Mermod, J.J.; Ernst, J.F.; Hirschi, M.; DeLamarter, J.F.

1987-01-01

Human granulocyte/macrophage colony-stimulating factor (hGM-CSF) produced by several recombinant sources including Escherichia coli, yeast, and animal cells was studied. Recombinant animal cells produced hGM-CSF in low quantities and in multiple forms of varying size. Mammalian hGM-CSF was purified 200,000-fold using immunoaffinity and lectin chromatography. Partially purified proteins produced in yeast and mammalian cells were assayed for the effects of deglycosylation. Following enzymatic deglycosylation, immunoreactivity was measured by radioimmunoassay and biological activity was measured in vitro on responsive human primary cells. Removal of N-linked oligosaccharides from both proteins increased their immunoreactivities by 4- to 8-fold. Removal of these oligosaccharides also increased their specific biological activities about 20-fold, to reach approximately the specific activity of recombinant hGM-CSF from E. coli. The E. coli produced-protein-lacking any carbohydrate- had by far the highest specific activity observed for the recombinant hGM-CSFs

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.

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

Science.gov (United States)

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. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Do Pine Trees in Aspen Stands Increase Bird Diversity

OpenAIRE

Rumble, Mark A; Mills, Todd R; Dystra, Brian L; Flake, Lester D

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. Al- though the Black Hills National forest is removing conifers (primarily ponderosa pine [Pinus ponderosa])toincreasetheaspencommunitiesinsomemixedstands,ForestPlan guidelines allow four conifers per hectare to remain to increase diversity in the remaining aspen stand. We compared bird species richness in pure ponderosa pine, mixed stands ...

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

Biomass of Sacrificed Spruce/Aspen (SNF)

Data.gov (United States)

National Aeronautics and Space Administration — Dimension analysis (diameter at breast high, tree height, depth of crown), estimated leaf area, and total aboveground biomass for sacrificed spruce and aspens in...

Mycorrhizal fungi of aspen forests: Natural occurrence and potential applications

Science.gov (United States)

Cathy L. Cripps

2001-01-01

Native mycorrhizal fungi associated with aspen were surveyed on three soil types in the north-central Rocky Mountains. Selected isolates were tested for the ability to enhance aspen seedling growth in vitro. Over 50 species of ectomycorrhizal fungi occur with Populus tremuloides in this region, primarily basidiomycete fungi in the Agaricales. Almost one-third (30%)...

Synergetic hydrothermal co-liquefaction of crude glycerol and aspen wood

DEFF Research Database (Denmark)

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

2015-01-01

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...

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.

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.

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.

PHYTOALEXIN DEFICIENT 4 affects reactive oxygen species metabolism, cell wall and wood properties in hybrid aspen (Populus tremula L. × tremuloides).

Science.gov (United States)

Ślesak, Ireneusz; Szechyńska-Hebda, Magdalena; Fedak, Halina; Sidoruk, Natalia; Dąbrowska-Bronk, Joanna; Witoń, Damian; Rusaczonek, Anna; Antczak, Andrzej; Drożdżek, Michał; Karpińska, Barbara; Karpiński, Stanisław

2015-07-01

The phytoalexin deficient 4 (PAD4) gene in Arabidopsis thaliana (AtPAD4) is involved in the regulation of plant--pathogen interactions. The role of PAD4 in woody plants is not known; therefore, we characterized its function in hybrid aspen and its role in reactive oxygen species (ROS)-dependent signalling and wood development. Three independent transgenic lines with different suppression levels of poplar PAD expression were generated. All these lines displayed deregulated ROS metabolism, which was manifested by an increased H2O2 level in the leaves and shoots, and higher activities of manganese superoxide dismutase (MnSOD) and catalase (CAT) in the leaves in comparison to the wild-type plants. However, no changes in non-photochemical quenching (NPQ) between the transgenic lines and wild type were observed in the leaves. Moreover, changes in the ROS metabolism in the pad4 transgenic lines positively correlated with wood formation. A higher rate of cell division, decreased tracheid average size and numbers, and increased cell wall thickness were observed. The results presented here suggest that the Populus tremula × tremuloides PAD gene might be involved in the regulation of cellular ROS homeostasis and in the cell division--cell death balance that is associated with wood development. © 2014 John Wiley & Sons Ltd.

Simulating the Dependence of Aspen on Redistributed Snow

Science.gov (United States)

Soderquist, B.; Kavanagh, K.; Link, T. E.; Seyfried, M. S.; Winstral, A. H.

2013-12-01

In mountainous regions across the western USA, the distribution of aspen (Populus tremuloides) is often directly related to heterogeneous soil moisture subsidies resulting from redistributed snow. With decades of climate and precipitation data across elevational and precipitation gradients, the Reynolds Creek Experimental Watershed (RCEW) in southwest Idaho provides a unique opportunity to study the relationship between aspen and redistributed snow. Within the RCEW, the total amount of precipitation has not changed in the past 50 years, but there are sharp declines in the percentage of the precipitation falling as snow. As shifts in the distribution of available moisture continue, future trends in aspen net primary productivity (NPP) remain uncertain. In order to assess the importance of snowdrift subsidies, NPP of three aspen stands was simulated at sites spanning elevational and precipitation gradients using the biogeochemical process model BIOME-BGC. At the aspen site experiencing the driest climate and lowest amount of precipitation from snow, approximately 400 mm of total precipitation was measured from November to March of 2008. However, peak measured snow water equivalent (SWE) held in drifts directly upslope of this stand was approximately 2100 mm, 5 times more moisture than the uniform winter precipitation layer initially assumed by BIOME-BGC. BIOME-BGC simulations in dry years forced by adjusted precipitation data resulted in NPP values approximately 30% higher than simulations assuming a uniform precipitation layer. Using BIOME-BGC and climate data from 1985-2011, the relationship between simulated NPP and measured basal area increments (BAI) improved after accounting for redistributed snow, indicating increased simulation representation. In addition to improved simulation capabilities, soil moisture data, diurnal branch water potential, and stomatal conductance observations at each site detail the use of soil moisture in the rooting zone and the onset

Stand development of trembling aspen in Canaan Valley, West Virginia

Science.gov (United States)

James S. Rentch; James T. Anderson

2008-01-01

In wetlands of Canaan Valley, West Virginia, trembling aspen occurs as a disjunct population well south of its primary natural range. Based on sample data from 15 stands, we found that aspen occurs as nearly monospecific stands or clones. Eight stands had median ages between 30 and 40 yrs, and we suggest that stand initiation was related to changes in land use after...

Mediation of glycosylated and partially-deglycosylated glucose oxidase of Aspergillus niger by a ferrocene-derivatised detergent.

Science.gov (United States)

Fraser, D M; Zakeeruddin, S M; Grätzel, M

1992-01-30

A ferrocene-derivatised detergent, (11-ferrocenylundecyl) trimethylammonium bromide (FTMAB), when oxidised to the corresponding ferricinium ion, was found by electrochemical studies to be an effective electron acceptor for reduced glucose oxidase of Aspergillus niger (EC 1.13.4) and thus acts as a electron-transfer mediator between glucose oxidase and a working electrode held at a potential sufficiently positive to reoxidise reduced FTMAB. An increase in mediating activity was produced when FTMAB was present in concentrations above its critical micelle concentration. An 'enzyme electrode' was formed by adsorption of glucose oxidase and FTMAB surfactant on a graphite rod. The electrode functioned as an amperometric biosensor for glucose in phosphate-buffered saline solution. A mixed micelle of glucose oxidase and FTMAB, probably adsorbed on the electrode surface, appears to be advantageous for the amperometric determination of glucose. Additionally, glucose oxidase was treated with alpha-mannosidase. When this partially-deglycosylated glucose oxidase was incorporated in an enzyme electrode, a 100-fold increase in the second-order rate constant (k) for electron transfer between the enzyme and FTMAB was observed, together with increased current densities, with respect to the equivalent values for FTMAB and commercial glucose oxidase. The use of deglycosylated enzymes in biosensors is suggested.

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...

Trembling aspen response to a mixed-severity wildfire in the Black Hills, South Dakota, USA

Science.gov (United States)

Tara L. Keyser; Frederick W. Smith; Wayne D. Shepperd

2005-01-01

Trembling aspen (Populus tremuloides Michx.) regeneration dynamics including sprout production, growth, and clone size were measured to determine the effects of fire on small aspen clone persistence following a mixedseverity wildfire in the Black Hills, South Dakota. Four years postfire, 10 small, isolated aspen clones per low and high fire severity...

Aspen Characteristics - Plumas National Forest [ds373

Data.gov (United States)

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

Aspen Characteristics - Klamath National Forest [ds369

Data.gov (United States)

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

Aspen Characteristics - Sequoia National Forest [ds377

Data.gov (United States)

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

Optimization of composition and technology for tablets containing aspen bark extract

Directory of Open Access Journals (Sweden)

O. I. Onуshkiv

2015-04-01

Full Text Available Summary. Influence of quantitativefactorsof basic quality parameters has been investigated for tabletscontainingextractofaspenbark, receivedbydirect pressingmethodand mathematicalplanningof experiment.To set the optimal composition of tablets containingaspen bark extract the proportion ofProsolv 90, Ludiflash and Polyplasdone XL 10 has been studied. The relationship between the studied factors and parameters of tablets’ regression models has been described. As a result tablets containing aspen bark extractwith mentioned above formula match necessary pharmaco-technological parameters of State Pharmacopoeia of Ukraine. Introduction.Peptic and duodenal ulcer are serious problems in modern medicine. According to statistics this disease is found in 12,83 % of the adult population in Ukraine [1]. Among the remedies for treatment and prevention of peptic ulcers we can find herbal medicines that may be used in the treatment of pre-peptic conditions and during an acute period as a means of adjuvant therapy in combination with strong remedies [2]. An antacid, cytoprotective, anti-inflammatory and reparative actions of aspen bark extract were proved by the researches of domestic and foreign scientists [3, 4]. Previously, we researched the mutual influence of excipients on the main indicators of quality of aspen bark extract tablets obtained by direct compression method. Due to these researches the best excipientshave been selected. It is necessary to establish the optimal quantitative proportion of excipients in order to obtain the tablets with suitable parameters that satisfy the requirements of the State Pharmacopoeia of Ukraine (SPU [5, 6]. Rational selection of excipients requires wide range of studies to obtain the optimal composition of the tablets containing aspen bark extract. Using mathematical planning of the experiment gives the possibility to reduce the number of experiments and to obtain the most detailed results of researches about effects

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%...

Aspen Characteristics - Lassen National Forest [ds371

Data.gov (United States)

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

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.

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

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. PMID:22662190

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.

THERAPEUTIC EFFECTS OF HIGHLY PURIFIED DE-GLYCOSYLATED GCMAF IN THE IMMUNOTHERAPY OF PATIENTS WITH CHRONIC DISEASES

OpenAIRE

Lynda Thyer; Emma Ward; Rodney Smith; Jacopo J.V. Branca; Gabriele Morucci; Massimo Gulisano; David Noakes; Stefania Pacini

2013-01-01

The de-Glycosylated vitamin D binding protein is a powerful Macrophage Activating Factor (GcMAF) that shows multiple biological effects that could be exploited in the immunotherapy of tumours, viral infections and autism. Here we report the observation of a series of clinical cases describing the results obtained administering highly purified GcMAF to patients with diverse types of chronic diseases. These are heterogeneous and refer to patients with different types of diseases at different s...

Aspen Forest Cover by Stratum/Plot (SNF)

Data.gov (United States)

National Aeronautics and Space Administration — Average percent coverage and standard deviation of each canopy stratum from subplots at each aspen site during the SNF study in the Superior National Forest, Minnesota

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.

Using Aspen simulation package to determine solubility of mixed salts in TRU waste evaporator bottoms

Energy Technology Data Exchange (ETDEWEB)

Hatchell, J.L.

1998-03-01

Nitric acid from plutonium process waste is a candidate for waste minimization by recycling. Process simulation software packages, such as Aspen, are valuable tools to estimate how effective recovery processes can be, however, constants in equations of state for many ionic components are not in their data libraries. One option is to combine single salt solubility`s in the Aspen model for mixed salt system. Single salt solubilities were regressed in Aspen within 0.82 weight percent of literature values. These were combined into a single Aspen model and used in the mixed salt studies. A simulated nitric acid waste containing mixed aluminum, calcium, iron, magnesium and sodium nitrate was tested to determine points of solubility between 25 and 100 C. Only four of the modeled experimental conditions, at 50 C and 75 C, produced a saturated solution. While experimental results indicate that sodium nitrate is the first salt to crystallize out, the Aspen computer model shows that the most insoluble salt, magnesium nitrate, the first salt to crystallize. Possible double salt formation is actually taking place under experimental conditions, which is not captured by the Aspen model.

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.

The Fate of Aspen in a World with Diminishing Snowpacks

Science.gov (United States)

Kavanagh, K.; Link, T. E.; Seyfried, M. S.; Kemp, K. B.

2010-12-01

Aspen (Populus tremuloides) productivity is tightly coupled with soil moisture. In the mountainous regions of the western USA, annual replenishment of soil moisture commonly occurs during snowmelt. Therefore, snow pack depth and duration can play an important role in sustaining aspen productivity. The presence of almost 50 years of detailed climate data across an elevational transect in the Reynolds Creek Experimental Watershed (RCEW) in southwestern Idaho offers a novel opportunity to better understand the role of shifting precipitation patterns on aspen productivity. Over the past 50 years, the proportion of the precipitation falling in the form of snow decreased by almost a factor of 2 at mid to low elevations in the RCEW, coupled with a roughly four week advance of snow ablation, and decline of large snow drifts that release moisture into the early summer. Results from growth ring increment, stable isotope analysis, sapflux and a process model (Biome BGC), will be used to determine the impact of shifting precipitation patterns on tree productivity along this transect over the past 50 years. Aspen trees located on moist microsites continue to transpire water and maintain high stomatal conductance 21 days later in the growing season relative to individuals on drier microsites. Predictions of net primary productivity (NPP) in aspen are very sensitive to precipitation patterns. NPP becomes negative as early as day 183 (90 days post budbreak) for years with little winter and spring precipitation whereas, in years with ample winter and spring precipitation, NPP remains positive until day 260 when leaf fall occurs. These results give unique insight into the conditions that deciduous tree species will encounter in a warming climate where snow water equivalent continues to diminish and soil moisture declines soon after budbreak occurs.

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

Widespread triploidy in Western North American aspen (Populus tremuloides.

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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.

Aspen Characteristics - Plumas National Forest, FRRD [ds375

Data.gov (United States)

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

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...

The yield of natural trembling aspen (populus tremula L.) stands (northern and eastern anatolia)

International Nuclear Information System (INIS)

Misir, M.; Misir, N.

2013-01-01

Trembling aspen (Populus tremula L.) is one of the most resistant to cold natural species in Turkey. In spite of its importance, there is no research on the yield. Hence, site productivity was determined and yield Table for undisturbed natural trembling aspen stands in Turkey was developed. Data were obtained from a total of 46 plots ranging in age from 17 to 82 years. Yield Table indicates that trembling aspen is very slow growing in young and middle age and Current Annual Increment (CAI) and Mean Annual Increment (MAI) values do not reach its maximum value, even at age 70. This is a proof that trembling aspen is not a fast growing species as expected. The reason for its slow growth is attributed to very short period of growth at very high altitudes. However, in the event of 50 years rotation age, mean annual volume increments of 8.0, 3.6 and 1.1 m3 are estimated for trembling aspen for site classes I, II and III, respectively. At extended rotations, trees of pole sizes could be obtained on all site classes. (author)

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

Nest-site selection and nest survival of Lewis's woodpecker in aspen riparian woodlands

Science.gov (United States)

Karen R. Newlon; Victoria A. Saab

2011-01-01

Riparian woodlands of aspen (Populus tremuloides) provide valuable breeding habitat for several cavity-nesting birds. Although anecdotal information for this habitat is available for Lewis's Woodpecker (Melanerpes lewis), no study has previously examined the importance of aspen woodlands to this species' breeding biology. From 2002 to 2004, we monitored 76...

Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

Directory of Open Access Journals (Sweden)

Teresa A. Newsome

2012-01-01

Full Text Available Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximized R2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. Maximum R2 values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

The aspen mortality summit; December 18 and 19, 2006; Salt Lake City, UT

Science.gov (United States)

Dale L. Bartos; Wayne D. Shepperd

2010-01-01

The USDA Forest Service Rocky Mountain Research Station sponsored an aspen summit meeting in Salt Lake City, Utah, on December 18 and19, 2006, to discuss the rapidly increasing mortality of aspen (Populus tremuloides) throughout the western United States. Selected scientists, university faculty, and managers from Federal, State, and non-profit agencies with experience...

Elevated atmospheric CO2 concentration leads to increased whole-plant isoprene emission in hybrid aspen (Populus tremula × Populus tremuloides).

Science.gov (United States)

Sun, Zhihong; Niinemets, Ülo; Hüve, Katja; Rasulov, Bahtijor; Noe, Steffen M

2013-05-01

Effects of elevated atmospheric [CO2] on plant isoprene emissions are controversial. Relying on leaf-scale measurements, most models simulating isoprene emissions in future higher [CO2] atmospheres suggest reduced emission fluxes. However, combined effects of elevated [CO2] on leaf area growth, net assimilation and isoprene emission rates have rarely been studied on the canopy scale, but stimulation of leaf area growth may largely compensate for possible [CO2] inhibition reported at the leaf scale. This study tests the hypothesis that stimulated leaf area growth leads to increased canopy isoprene emission rates. We studied the dynamics of canopy growth, and net assimilation and isoprene emission rates in hybrid aspen (Populus tremula × Populus tremuloides) grown under 380 and 780 μmol mol(-1) [CO2]. A theoretical framework based on the Chapman-Richards function to model canopy growth and numerically compare the growth dynamics among ambient and elevated atmospheric [CO2]-grown plants was developed. Plants grown under elevated [CO2] had higher C : N ratio, and greater total leaf area, and canopy net assimilation and isoprene emission rates. During ontogeny, these key canopy characteristics developed faster and stabilized earlier under elevated [CO2]. However, on a leaf area basis, foliage physiological traits remained in a transient state over the whole experiment. These results demonstrate that canopy-scale dynamics importantly complements the leaf-scale processes, and that isoprene emissions may actually increase under higher [CO2] as a result of enhanced leaf area production. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

76 FR 69279 - Notice of Intent to Prepare an Environmental Impact Statement for the Quaking Aspen Wind Energy...

Science.gov (United States)

2011-11-08

... Intent to Prepare an Environmental Impact Statement for the Quaking Aspen Wind Energy Project, Wyoming... Statement (EIS) for the Quaking Aspen Wind Energy Project (Quaking Aspen). By this notice, BLM is: (1..._Wind_Energy[email protected] ; or Mail: 280 Highway 191 N., Rock Springs, WY 82901. Documents pertinent to...

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...

Chemical studies on oils derived from aspen poplar wood, cellulose, and an isolated aspen poplar lignin

Energy Technology Data Exchange (ETDEWEB)

Eager, R L; Pepper, J M; Roy, J C; Mathews, J F

1983-01-01

An initial study has been made of the chemical nature of the oil phase resulting from the conversion of aspen poplar wood, cellulose, and an isolated lignin from the aspen poplar as a result of their interactions with water and carbon monoxide in the presence of sodium carbonate at 360 degrees C. Gas chromatographic analysis of the sodium hydroxide soluble fractions from each substrate revealed similar spectra of alkyl-substituted phenols. The relative abundance of identified low molecular weight phenolic compounds decreased from lignin to wood to cellulose. This was in agreement with the known phenolic nature of lignin. As well, it confirmed the synthesis during reaction of such compounds from a carbohydrate substrate. Gas chromatographic analysis of the whole oils also revealed the presence in each case of several alkyl-substituted cyclopentanones whose relative abundance decreased from cellulose to wood to lignin. Silica gel column separation of the oils, after a charcoal treatment, followed by capillary gas chromatographic - mass spectrometric analyses of the resulting fraction indicated the presence of other higher molecular weight phenols, napthols, cycloalkanols, and polycyclic and long chain alkanes and alkenes.

Evaluation to the aspen for the air pollution monitoring

International Nuclear Information System (INIS)

De La Rosa, D.; Lima, L.; Santana, J.L.; Olivares, S.; Martin, R.; Garcia, M.

2003-01-01

Aspen is not often used in bio monitoring programs, but when it is, several interacting and confounding variables have to be considered. Biomass of leaves, and height changes are not easy linked with air pollution, whereas dry weight and leaf abscission are. Visible injury diagnosis and crown thinning are useful records for bio monitoring programs to consider, but skill and understanding of air pollution effects versus seasonal effects are very important. Understanding of actual air pollution symptoms and elemental ratios are especially important. Clonal response and heritability is discuses below, and has to be considered in any bio monitoring program. Above all, integration of aspen response with other key variables is key

Leaf chemical composition of twenty-one Populus hybrid clones grown under intensive culture

Science.gov (United States)

Richard E. Dickson; Philip R. Larson

1976-01-01

Leaf material from 21 nursery-grown Populus hybrid clones was analyzed for three nitrogen fractions (total N, soluble protein, and soluble amino acids) and three carbhydrate fractions (reducing sugars, total soluble sugars, and total nonstructural carbohydrates-TNC). In addition, nursery-grown green ash and silver maple, field-grown bigtooth and trembling aspen, and...

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.

Habitone analysis of quaking aspen in the Utah Book Cliffs: Effects of site water demand and conifer cover

Science.gov (United States)

Joseph O. Sexton; R. Douglas Ramsey; Dale L. Bartos

2006-01-01

Quaking aspen (Populus tremuloides Michx.) is the most widely distributed tree species in North America, but its presence is declining across much of the Western United States. Aspen decline is complex, but results largely from two factors widely divergent in temporal scale: (1) Holocene climatic drying of the region has led to water limitation of aspen seedling...

Experimental Study of Impregnation Birch and Aspen Samples

Directory of Open Access Journals (Sweden)

Igor Vladislavovich Grigorev

2014-10-01

Full Text Available An experimental study of wood impregnation was implemented by applying centrifugal methods. The impregnants were a 10% aqueous solution of potassium chloride and a 2% aqueous solution of borax. Birch (Betula pendula and aspen (Populus tremula wood samples in different moisture content were tested. The impregnation time in the centrifugal device were 30 seconds repeated 21 times, and the samples were measured after every 30 seconds. The experimental results were fitted to a nonlinear filtration law, which indicated that the centrifugal wood impregnation was dependent on wood species, wood moisture, rotational speed, and radius. Determination of rotational speed and centrifuge radius for impregnating aspen and birch at varying lengths and humidity under conditions of the nonlinear impregnant filtration law can be done using the example charts that were developed and presented in this study.

Aspen HYSYS process simulation and Aspen ICARUS cost estimation of CO2 removal plant

OpenAIRE

Vozniuk, Ievgeniia Oleksandrivna

2010-01-01

An Aspen HYSYS model of CO2 removal was developed and modified with a split-stream configuration in order to reduce energy consumption in the reboiler. The model has been calculated with variation of parameters to optimize the process and find an optimum solution. For the selected base cases the heat exchanger minimum temperature difference was specified to 10K and the removal efficiency was 85%. The reboiler duty of 3.8 MJ/kg CO2 removed for the standard process without split-stream was ...

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

Allozyme and microsatellite data reveal small clone size and high genetic diversity in aspen in the southern Cascade Mountains

Science.gov (United States)

Jennifer DeWoody; Thomas H. Rickman; Bobette E. Jones; Valerie D. Hipkins

2009-01-01

The most widely distributed tree in North America, quaking aspen (Populus tremuloides, Michx.), reproduces sexually via seed and clonally via suckers. The size of aspen clones varies geographically, generally smaller in the east and large in the arid Intermountain West. In order to describe clone size and genetic structure of aspen in the southern Cascade...

Modeling the Removal of Xenon from Lithium Hydrate with Aspen HYSYS

Science.gov (United States)

Efthimion, Phillip; Gentile, Charles

2011-10-01

The Laser Inertial Fusion Engine (LIFE) project mission is to provide a long-term, carbon-free source of sustainable energy, in the form of electricity. A conceptual xenon removal system has been modeled with the aid of Aspen HYSYS, a chemical process simulator. Aspen HYSYS provides excellent capability to model chemical flow processes, which generates outputs which includes specific variables such as temperature, pressure, and molar flow. The system is designed to strip out hydrogen isotopes deuterium and tritium. The base design bubbles plasma exhaust laden with x filled with liquid helium. The system separates the xenon from the hydrogen, deuterium, and tritium with a lithium hydrate and a lithium bubbler. After the removal of the hydrogen and its isotopes, the xenon is then purified by way of the process of cryogenic distillation. The pure hydrogen, deuterium, and tritium are then sent to the isotope separation system (ISS). The removal of xenon is an integral part of the laser inertial fusion engine and Aspen HYSYS is an excellent tool to calculate how to create pure xenon.

Effects of genotype, elevated CO2 and elevated O3 on aspen phytochemistry and aspen leaf beetle Chrysomela crotchi performance

Science.gov (United States)

Leanne M. Vigue; Richard L. Lindroth

2010-01-01

Trembling aspen Populus tremuloides Michaux is an important forest species in the Great Lakes region and displays tremendous genetic variation in foliar chemistry. Elevated carbon dioxide (CO2) and ozone (O3) may also influence phytochemistry and thereby alter the performance of insect herbivores such as...

Estimating white trunk rot in aspen stands

Science.gov (United States)

Alan C. Jones; Michael E. Ostry

1998-01-01

Advanced decay caused by Phellinus tremulae was estimated in 295 trembling aspen on 30 plots in 2 Minnesota counties using existing inventory guides, and then measured by felling and sectioning the trees. In standing trees, decay volume was underestimated by 38% compared to measured decay volume in felled trees. The most reliable external indicator...

Modeling of existing cooling towers in ASPEN PLUS using an equilibrium stage method

International Nuclear Information System (INIS)

Queiroz, João A.; Rodrigues, Vitor M.S.; Matos, Henrique A.; Martins, F.G.

2012-01-01

Highlights: ► Simulation of cooling tower performance under different operating conditions. ► Cooling tower performance is simulated using ASPEN PLUS. ► Levenberg–Marquardt method used to adjust model parameters. ► Air and water outlet temperatures are in good accordance with experimental data. - Abstract: Simulation of cooling tower performance considering operating conditions away from design is typically based on the geometrical parameters provided by the cooling tower vendor, which are often unavailable or outdated. In this paper a different approach for cooling tower modeling based on equilibrium stages and Murphree efficiencies to describe heat and mass transfer is presented. This approach is validated with published data and with data collected from an industrial application. Cooling tower performance is simulated using ASPEN PLUS. Murphree stage efficiency values for the process simulator model were optimized by minimizing the squared difference between the experimental and calculated data using the Levenberg–Marquardt method. The minimization algorithm was implemented in Microsoft Excel with Visual Basic for Applications, integrated with the process simulator (ASPEN PLUS) using Aspen Simulation Workbook. The simulated cooling tower air and water outlet temperatures are in good accordance with experimental data when applying only the outlet water temperature to calibrate the model. The methodology is accurate for simulating cooling towers at different operational conditions.

2012 Aspen Winter Conferences on High Energy and Astrophysics

Energy Technology Data Exchange (ETDEWEB)

Campbell, John [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Olivier, Dore [California Inst. of Technology (CalTech), Pasadena, CA (United States); Fox, Patrick [Aspen Center for Physics, CO (United States); Furic, Ivan [Univ. of Florida, Gainesville, FL (United States); Halkiadakis, Eva [Rutgers Univ., Piscataway, NJ (United States); Schmidt, Fabian [California Inst. of Technology (CalTech), Pasadena, CA (United States); Senatore, Leonardo [Stanford Univ., CA (United States); Smith, Kendrick M. [Princeton Univ., NJ (United States); Whiteson, Daniel [Univ. of California, Irvine, CA (United States)

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

Study of a SOFC-PEM hybrid system

International Nuclear Information System (INIS)

Fillman, B.; Bjornbom, P.; Sylwan, C.

2004-01-01

'Full text:' In the present project a system study of a SOFC-PEM hybrid system is in progress. Positive synergy effects are expected when combining a SOFC system with a PEM system. By combining the advantages of each fuel cell type it is promising that the hybrid system has higher overall efficiency than a SOFC-only system or a reformer-PEM system. A SOFC stack produces electricity and a reformate gas that can be further processed to hydrogen by the shift reaction. The produced hydrogen can be used by PEM stack in order to produce further electricity. In the PEM system case the complex fuel reformer processing could be eliminated. The simulations were performed with the flowsheeting simulation software Aspen Plus. (author)

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.

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.

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.

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.

Colocalization of low-methylesterified pectins and Pb deposits in the apoplast of aspen roots exposed to lead

International Nuclear Information System (INIS)

Rabęda, Irena; Bilski, Henryk; Mellerowicz, Ewa J.; Napieralska, Anna; Suski, Szymon; Woźny, Adam; Krzesłowska, Magdalena

2015-01-01

Low-methylesterified homogalacturonans have been suggested to play a role in the binding and immobilization of Pb in CW. Using root apices of hybrid aspen, a plant with a high phytoremediation potential, as a model, we demonstrated that the in situ distribution pattern of low-methylesterified homogalacturonan, pectin epitope (JIM5-P), reflects the pattern of Pb occurrence. The region which indicated high JIM5-P level corresponded with “Pb accumulation zone”. Moreover, JIM5-P was especially abundant in cell junctions, CWs lining the intercellular spaces and the corners of intercellular spaces indicating the highest accumulation of Pb. Furthermore, JIM5-P and Pb commonly co-localized. The observations indicate that low-methylesterified homogalacturonan is the CW polymer that determines the capacity of CW for Pb sequestration. Our results suggest a promising directions for CW modification for enhancing the efficiency of plant roots in Pb accumulation, an important aspect in the phytoremediation of soils contaminated with trace metals. - Highlights: • Co-localization of low-methylesterified pectins and Pb was analysed in situ. • The pattern of Pb accumulation matched low-methylesterified pectins distribution. • Low-methylesterified pectins and Pb commonly co-localized in cell walls. • Low-methylesterified pectins revealed an important compound in Pb sequestration. • We suggest a new direction in enhancing plant efficiency for phytoremediation. - The distribution of lead in developing tissues of aspen root tips exposed to short-term lead treatment mimics the distribution of low-methylesterified pectin epitope

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…

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.

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.

Analysis of Cryogenic Cycle with Process Modeling Tool: Aspen HYSYS

International Nuclear Information System (INIS)

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

2015-01-01

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

Summary and abstracts from Sudden Aspen Decline (SAD) Meeting; Fort Collins, Colorado, February 12-13, 2008

Science.gov (United States)

Paul C. Rogers

2008-01-01

In recent years the aspen research and management community has witnessed increasing accounts of unexplained aspen die-offs across the Rocky Mountain region. In response, two meetings were held to address the issue; this paper summarizes the most recent gathering, a symposium held in Fort Collins at the USDA Forest Service, Rocky Mountain Research Station, on February...

Impacts of climate and insect defoliators on productivity and function of trembling aspen (Populus tremuloides) in Alaskan boreal forests

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Boyd, M. A.; Walker, X. J.; Rogers, B. M.; Goetz, S. J.; Wagner, D.; Mack, M. C.

2017-12-01

Climate change has increased tree mortality and growth decline in forested ecosystems worldwide. In response to warming and drying of the boreal forest, trembling aspen (Populus tremuloides) has experienced recent large-scale productivity declines. Although declines in productivity are thought to be primarily a result of moistures stress, infestation is another major driver of aspen decline and may interact strongly with climate. Throughout interior Alaska widespread and consistent foliar damage by the aspen epidermal leaf miner Phyllocnistis populiella has been observed concurrent with some of the warmest and driest growing seasons on record. Here we use tree ring measurements and remote sensing indices of vegetation productivity (NDVI) to study the influence of leaf miner and climate on aspen productivity and physiology in the Alaskan boreal forest, and assess if NDVI reflects variations in these ground-based measurements. We assessed ring width and tree ring stable carbon isotope (d13C) response of aspen to infestation and a climate moisture index (CMI) from 2004 - 2014. We found that when growth was negatively correlated to infestation, then it was no longer positively influenced by moisture availability during the growing season. Regardless of the radial growth response to leaf mining, tree ring d13C decreased with increasing infestation. We also found that NDVI was influenced by leaf mining and showed a positive correlation with tree ring d13C, which suggests that NDVI is reflective of changes in tree characteristics under leaf mining that influence tree ring d13C. This finding also reveals the prospect of using satellite data to monitor fluctuations in tree physiology during leaf miner infestation. Our results indicate that aspen productivity will be severely hindered during leaf miner infestation, and that infestation will inhibit the ability of aspen to respond to favorable climate conditions by increasing growth and potentially photosynthesis. This

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

Science.gov (United States)

Chaffey, Nigel; Barlow, Peter; Sundberg, Björn

2002-03-01

The involvement of microfilaments and microtubules in the development of the radial and axial components of secondary xylem (wood) in hybrid aspen (Populus tremula L. x P. tremuloides Michx.) was studied by indirect immunofluorescent localization techniques. In addition to cambial cells, the differentiated cell types considered were early- and late-wood vessel elements, axial parenchyma, normal-wood fibers and gelatinous fibers, and contact and isolation ray cells. Microfilaments were rare in ray cambial cells, but were abundant and axially arranged in their derivatives once cell elongation had begun, and persisted in that orientation in mature ray cells. Microfilaments were axially arranged in fusiform cambial cells and persisted in that orientation in all xylem derivatives of those cells. Microtubules were randomly oriented in ray and fusiform cells of the cambial zone. Dense arrays of parallel-aligned microtubules were oriented near axially in the developing gelatinous fibers, but at a wide range of angles in normal-wood fibers. Ellipses of microfilaments were associated with pit development in fiber cells and isolation ray cells. Rings of co-localized microtubules and microfilaments were associated with developing inter-vessel bordered pits and vessel-contact ray cell contact pits, and, in the case of bordered pits, these rings decreased in diameter as the over-arching pit border increased in size. Although only microtubules were seen at the periphery of the perforation plate of vessel elements, a prominent meshwork of microfilaments overlaid the perforation plate itself. A consensus view of the roles of the cytoskeleton during wood formation in angiosperm trees is presented.

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.

Moderate-scale mapping methods of aspen stand types: a case study for Cedar Mountain in southern Utah

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Chad M. Oukrop; David M. Evans; Dale L. Bartos; R. Douglas Ramsey; Ronald J. Ryel

2011-01-01

Quaking aspen (Populus tremuloides Michx.) are the most widely distributed tree species across North America, but its dominance is declining in many areas of the western United States, with certain areas experiencing rapid mortality events over the past decade. The loss of aspen from western landscapes will continue to profoundly impact biological, commercial, and...

Growing Season Conditions Mediate the Dependence of Aspen on Redistributed Snow Under Climate Change.

Science.gov (United States)

Soderquist, B.; Kavanagh, K.; Link, T. E.; Seyfried, M. S.; Strand, E. K.

2016-12-01

Precipitation regimes in many semiarid ecosystems are becoming increasingly dominated by winter rainfall as a result of climate change. Across these regions, snowpack plays a vital role in the distribution and timing of soil moisture availability. Rising temperatures will result in a more uniform distribution of soil moisture, advanced spring phenology, and prolonged growing seasons. Productive and wide ranging tree species like aspen, Populus tremuloides, may experience increased vulnerability to drought and mortality resulting from both reduced snowpack and increased evaporative demand during the growing season. We simulated the net primary production (NPP) of aspen stands spanning the rain:snow transition zone in the Reynolds Creek Critical Zone Observatory (RCCZO) in southwest Idaho, USA. Within the RCCZO, the total amount of precipitation has remained unchanged over the past 50 years, however the percentage of the precipitation falling as snow has declined by approximately 4% per decade at mid-elevation sites. The biogeochemical process model Biome-BGC was used to simulate aspen NPP at three stands located directly below snowdrifts that provide melt water late into the spring. After adjusting precipitation inputs to account for the redistribution of snow, we assessed climate change impacts on future aspen productivity. Mid-century (2046-2065) aspen NPP was simulated using temperature projections from a multi-model average under high emission conditions using the Multivariate Adaptive Constructed Analogs (MACA) data set. While climate change simulations indicated over a 20% decrease in annual NPP for some years, NPP rates for other mid-century years remained relatively unchanged due to variations in growing season conditions. Mid-century years with the largest decreases in NPP typically showed increased spring transpiration rates resulting from earlier leaf flush combined with warmer spring conditions. During these years, the onset of drought stress occurred

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.

Bioenergy harvest impacts to biodiversity and resilience vary across aspen-dominated forest ecosystems in the Lake States region, USA

Science.gov (United States)

Miranda T. Curzon; Anthony W. D' Amato; Brian J. Palik; Kris Verheyen

2016-01-01

Questions: Does the increase in disturbance associated with removing harvest residues negatively impact biodiversity and resilience in aspen-dominated forest ecosystems? How do responses of functional diversity measures relate to community recovery and standing biomass? Location: Aspen (Populus tremuloides, Michx.) mixedwood forests in Minnesota...

Defining Excellence: Lessons from the 2013 Aspen Prize Finalists

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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…

Deglycosylation of serum vitamin D3-binding protein by alpha-N-acetylgalactosaminidase detected in the plasma of patients with systemic lupus erythematosus.

Science.gov (United States)

Yamamoto, N; Naraparaju, V R; Moore, M; Brent, L H

1997-03-01

A serum glycoprotein, Gc protein (vitamin D3-binding protein), can be converted by beta-galactosidase of B cells and sialidase of T cells to a potent macrophage-activating factor (MAF), a protein with N-acetylgalactosamine as the remaining sugar moiety. Thus, Gc protein is the precursor for MAF. Treatment of Gc protein with immobilized beta-galactosidase and sialidase generates a remarkably high titered macrophage-activating factor (GcMAF). When peripheral blood monocytes/ macrophages (designated macrophages) of 33 systemic lupus erythematosus patients were incubated with GcMAF (100 pg/ml), the macrophages of all patients were activated as determined by superoxide generation. However, the precursor activity of patient plasma Gc protein was lost or reduced in these patients. Loss of the precursor activity was the result of deglycosylation of plasma Gc protein by alpha-N-acetylgalactosaminidase activity found in the patient plasma. Levels of plasma alpha-N-acetylgalactosaminidase activity in individual patients had an inverse correlation with the MAF precursor activity of their plasma Gc protein. Deglycosylated Gc protein cannot be converted to macro-phage-activating factor. The resulting defect in macro-phage activation may lead to an inability to clear pathogenic immune complexes. Thus, elevated plasma alpha-N-acetylgalactosaminidase activity resulting in the loss of MAF precursor activity and reduced macro-phage activity may play a role in the pathogenesis of systemic lupus erythematosus.

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.

An integrated sample pretreatment platform for quantitative N-glycoproteome analysis with combination of on-line glycopeptide enrichment, deglycosylation and dimethyl labeling

Energy Technology Data Exchange (ETDEWEB)

Weng, Yejing; Qu, Yanyan; Jiang, Hao; Wu, Qi [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); University of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Lihua, E-mail: lihuazhang@dicp.ac.cn [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Yuan, Huiming [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Zhou, Yuan [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); University of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Xiaodan; Zhang, Yukui [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

2014-06-23

Highlights: • An integrated platform for quantitative N-glycoproteome analysis was established. • On-line enrichment, deglycosylation and labeling could be achieved within 160 min. • A N{sub 2}-assisted interface was applied to improve the compatibility of the platform. • The platform exhibited improved quantification accuracy, precision and throughput. - Abstract: Relative quantification of N-glycoproteomes shows great promise for the discovery of candidate biomarkers and therapeutic targets. The traditional protocol for quantitative analysis of glycoproteomes is usually off-line performed, and suffers from long sample preparation time, and the risk of sample loss or contamination due to manual manipulation. In this study, a novel integrated sample preparation platform for quantitative N-glycoproteome analysis was established, with combination of online N-glycopeptide capture by a HILIC column, sample buffer exchange by a N{sub 2}-assisted HILIC–RPLC interface, deglycosylation by a hydrophilic PNGase F immobilized enzymatic reactor (hIMER) and solid dimethyl labeling on a C18 precolumn. To evaluate the performance of such a platform, two equal aliquots of immunoglobulin G (IgG) digests were sequentially pretreated, followed by MALDI-TOF MS analysis. The signal intensity ratio of heavy/light (H/L) labeled deglycosylated peptides with the equal aliquots was 1.00 (RSD = 6.2%, n = 3), much better than those obtained by the offline protocol, with H/L ratio as 0.76 (RSD = 11.6%, n = 3). Additionally, the total on-line sample preparation time was greatly shortened to 160 min, much faster than that of offline approach (24 h). Furthermore, such an integrated pretreatment platform was successfully applied to analyze the two kinds of hepatocarcinoma ascites syngeneic cell lines with high (Hca-F) and low (Hca-P) lymph node metastasis rates. For H/L labeled Hca-P lysates with the equal aliquots, 99.6% of log 2 ratios (H/L) of quantified glycopeptides ranged from −1

Earthworms, arthropods and plant litter decomposition in aspen (Populus tremuloides) and lodgepole pine(Pinus contorta) forests in Colorado, USA

Science.gov (United States)

Grizelle Gonzalez; Timothy R. Seastedt; Zugeily Donato

2003-01-01

We compared the abundance and community composition of earthworms, soil macroarthropods, and litter microarthropods to test faunal effects on plant litter decomposition rates in two forests in the subalpine in Colorado, USA. Litterbags containing recently senesced litter of Populus tremuloides (aspen) and Pinus contorta (lodgepole pine) were placed in aspen and pine...

Historical patterns in lichen communities of montane quaking aspen forests

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Paul C. Rogers; Dale L. Bartos; Ronald J. Ryel

2011-01-01

Climate shifts and resource exploitation in Rocky Mountain forests have caused profound changes in quaking aspen (Populus tremuloides Michx.) structure and function since Euro-American settlement. It therefore seems likely that commensurate shifts in dependent epiphytes would follow major ecological transitions. In the current study, we merge several lines of inquiry...

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

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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

The potential of aspen clonal forestry in Alberta: breeding regions and estimates of genetic gain from selection.

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Tim Gylander

Full Text Available BACKGROUND: Aspen naturally grows in large, single-species, even-aged stands that regenerate clonally after fire disturbance. This offers an opportunity for an intensive clonal forestry system that closely emulates the natural life history of the species. In this paper, we assess the potential of genetic tree improvement and clonal deployment to enhance the productivity of aspen forests in Alberta. We further investigate geographic patterns of genetic variation in aspen and infer forest management strategies under uncertain future climates. METHODOLOGY/PRINCIPAL FINDINGS: Genetic variation among 242 clones from Alberta was evaluated in 13 common garden trials after 5-8 growing seasons in the field. Broad-sense heritabilities for height and diameter at breast height (DBH ranged from 0.36 to 0.64, allowing 5-15% genetic gains in height and 9-34% genetic gains in DBH. Geographic partitioning of genetic variance revealed predominant latitudinal genetic differentiation. We further observed that northward movement of clones almost always resulted in increased growth relative to local planting material, while southward movement had a strong opposite effect. CONCLUSION/SIGNIFICANCE: Aspen forests are an important natural resource in western Canada that is used for pulp and oriented strandboard production, accounting for ~40% of the total forest harvest. Moderate to high broad-sense heritabilities in growth traits suggest good potential for a genetic tree improvement program with aspen. Significant productivity gains appear possible through clonal selection from existing trials. We propose two breeding regions for Alberta, and suggest that well-tested southern clones may be used in the northern breeding region, accounting for a general warming trend observed over the last several decades in Alberta.

The Potential of Aspen Clonal Forestry in Alberta: Breeding Regions and Estimates of Genetic Gain from Selection

Science.gov (United States)

Gylander, Tim; Hamann, Andreas; Brouard, Jean S.; Thomas, Barb R.

2012-01-01

Background Aspen naturally grows in large, single-species, even-aged stands that regenerate clonally after fire disturbance. This offers an opportunity for an intensive clonal forestry system that closely emulates the natural life history of the species. In this paper, we assess the potential of genetic tree improvement and clonal deployment to enhance the productivity of aspen forests in Alberta. We further investigate geographic patterns of genetic variation in aspen and infer forest management strategies under uncertain future climates. Methodology/Principal Findings Genetic variation among 242 clones from Alberta was evaluated in 13 common garden trials after 5–8 growing seasons in the field. Broad-sense heritabilities for height and diameter at breast height (DBH) ranged from 0.36 to 0.64, allowing 5–15% genetic gains in height and 9–34% genetic gains in DBH. Geographic partitioning of genetic variance revealed predominant latitudinal genetic differentiation. We further observed that northward movement of clones almost always resulted in increased growth relative to local planting material, while southward movement had a strong opposite effect. Conclusion/Significance Aspen forests are an important natural resource in western Canada that is used for pulp and oriented strandboard production, accounting for ∼40% of the total forest harvest. Moderate to high broad-sense heritabilities in growth traits suggest good potential for a genetic tree improvement program with aspen. Significant productivity gains appear possible through clonal selection from existing trials. We propose two breeding regions for Alberta, and suggest that well-tested southern clones may be used in the northern breeding region, accounting for a general warming trend observed over the last several decades in Alberta. PMID:22957006

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...

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.

Development and validation of the activity significance personal evaluation (ASPEn) scale.

Science.gov (United States)

Mallinson, Trudy; Schepens Niemiec, Stacey L; Carlson, Mike; Leland, Natalie; Vigen, Cheryl; Blanchard, Jeanine; Clark, Florence

2014-12-01

Engagement in desired occupations can promote health and wellbeing in older adults. Assessments of engagement often measure frequency, amount or importance of specific activities. This study aimed to develop a scale to measure older adults' evaluation of the extent to which their everyday activities are contributing to their health and wellness. Eighteen items, each scored with a seven-point rating scale, were initially developed by content experts, covering perceptions of how daily activities contribute to physical and mental health, as well as satisfaction and activity participation in the last six months. Rasch analysis methods were used to refine the scale using the pencil and paper responses of 460 community-living older adults. Initial Rasch analysis indicated three unlabelled rating scale categories were seldom used, reducing measurement precision. Five items were conceptually different by misfit statistics and principal component analysis. Subsequently, those items were removed and the number of rating scale steps reduced to 4. The remaining 13-item, 4-step scale, termed the Activity Significance Personal Evaluation (ASPEn), formed a unidimensional hierarchy with good fit statistics and targeting. Person separation reliability (2.7) and internal consistency (.91) indicated the tool is appropriate for individual person measurement. Relative validity indicated equivalence between Rasch measures and total raw scores. ASPEn is a brief, easily administered assessment of older adults' perception of the contribution of everyday activities to personal health and wellness. ASPEn may facilitate occupational therapy practice by enabling clinicians to assess change in meaning of an older adult's activity over time. © 2014 Occupational Therapy Australia.

Physical property parameter set for modeling ICPP aqueous wastes with ASPEN electrolyte NRTL model

International Nuclear Information System (INIS)

Schindler, R.E.

1996-09-01

The aqueous waste evaporators at the Idaho Chemical Processing Plant (ICPP) are being modeled using ASPEN software. The ASPEN software calculates chemical and vapor-liquid equilibria with activity coefficients calculated using the electrolyte Non-Random Two Liquid (NRTL) model for local excess Gibbs free energies of interactions between ions and molecules in solution. The use of the electrolyte NRTL model requires the determination of empirical parameters for the excess Gibbs free energies of the interactions between species in solution. This report covers the development of a set parameters, from literature data, for the use of the electrolyte NRTL model with the major solutes in the ICPP aqueous wastes

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 ) Orig inal manuscript received 13 June 2012, revision accepted 31 October 2012 Vol 66 No 1 January - March 2013 1 PEER REVIEWED A study of polymerization of aspen (Populus) wood lipophilic extractives by SEC and Py-GC/MS BRUCE SITHOLE1*, LUC... of polymerized wood resin that will be difficult to remove if present in pulp and paper products. On the other hand, these problems may be minor compared to using unseasoned wood. KEYWORDS: Aspen, extractives, polymerization, size exclusion chromatography, Py...

Protection of macaques with diverse MHC genotypes against a heterologous SIV by vaccination with a deglycosylated live-attenuated SIV.

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Chie Sugimoto

Full Text Available HIV vaccine development has been hampered by issues such as undefined correlates of protection and extensive diversity of HIV. We addressed these issues using a previously established SIV-macaque model in which SIV mutants with deletions of multiple gp120 N-glycans function as potent live attenuated vaccines to induce near-sterile immunity against the parental pathogenic SIVmac239. In this study, we investigated the protective efficacy of these mutants against a highly pathogenic heterologous SIVsmE543-3 delivered intravenously to rhesus macaques with diverse MHC genotypes. All 11 vaccinated macaques contained the acute-phase infection with blood viral loads below the level of detection between 4 and 10 weeks postchallenge (pc, following a transient but marginal peak of viral replication at 2 weeks in only half of the challenged animals. In the chronic phase, seven vaccinees contained viral replication for over 80 weeks pc, while four did not. Neutralizing antibodies against challenge virus were not detected. Although overall levels of SIV specific T cell responses did not correlate with containment of acute and chronic viral replication, a critical role of cellular responses in the containment of viral replication was suggested. Emergence of viruses with altered fitness due to recombination between the vaccine and challenge viruses and increased gp120 glycosylation was linked to the failure to control SIV. These results demonstrate the induction of effective protective immune responses in a significant number of animals against heterologous virus by infection with deglycosylated attenuated SIV mutants in macaques with highly diverse MHC background. These findings suggest that broad HIV cross clade protection is possible, even in hosts with diverse genetic backgrounds. In summary, results of this study indicate that deglycosylated live-attenuated vaccines may provide a platform for the elucidation of correlates of protection needed for a

Response Surface Methodology and Aspen Plus Integration for the Simulation of the Catalytic Steam Reforming of Ethanol

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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.

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

Science.gov (United States)

Oldén, Anna; Ovaskainen, Otso; Kotiaho, Janne S; Laaka-Lindberg, Sanna; Halme, Panu

2014-01-01

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-growth forests.

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

Ozone-induced H2O2 accumulation in field-grown aspen and birch is linked to foliar ultrastructure and peroxisomal activity

Science.gov (United States)

E. Oksanen; E. Häikiö; J. Sober; D.F. Karnosky

2003-01-01

Saplings of three aspen (Populus tremuloides) genotypes and seedlings of paper birch (Betula papyrifera) were exposed to elevated ozone (1.5x ambient) and 560 p.p.m. CO2, singly and in combination, from 1998 at the Aspen-FACE (free-air CO2 enrichment) site (Rhinelander, USA).

Effects of elevated CO2 and ozone on phenolic glycosides of trembling aspen

Science.gov (United States)

James K. Nitao; Muraleedharan G. Nair; William J. Mattson; Daniel A. Herms; Bruce A. Birr; Mark D. Coleman; Terry M. Trier; J. G. Isebrands

1996-01-01

We tested the effects of elevated CO2 and ozone on concentrations of the phenolic glycosides salicortin and tremulacin in immature and mature foliage of the trembling aspen (Populus tremuloides) clones 216, 259, and 271.

Can Carbon Fluxes Explain Differences in Soil Organic Carbon Storage under Aspen and Conifer Forest Overstories?

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Antra Boča

2017-04-01

Full Text Available Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC storage and stability. Quaking aspen (Populus tremuloides Michx. is the most widespread tree species in North America, but fire exclusion often promotes the succession to conifer dominated forests. Aspen in the Western US have been found to store more SOC in the mineral soil than nearby conifers, but we do not yet fully understand the source of this differential SOC accumulation. We measured total SOC storage (0–50 cm, characterized stable and labile SOC pools, and quantified above- and belowground litter inputs and dissolved organic carbon (DOC fluxes during snowmelt in plots located in N and S Utah, to elucidate the role of foliage vs. root detritus in SOC storage and stabilization in both ecosystems. While leaf litterfall was twice as high under aspen as under conifers, input of litter-derived DOC with snowmelt water was consistently higher under conifers. Fine root (<2 mm biomass, estimated root detritus input, and root-derived DOC fluxes were also higher under conifers. A strong positive relationship between root and light fraction C content suggests that root detritus mostly fueled the labile fraction of SOC. Overall, neither differences in above- and belowground detritus C inputs nor in detritus-derived DOC fluxes could explain the higher and more stable SOC pools under aspen. We hypothesize that root–microbe–soil interactions in the rhizosphere are more likely to drive these SOC pool differences.

Analysis of alternative flow sheets for the hybrid chlorine cycle

Energy Technology Data Exchange (ETDEWEB)

Gooding, Charles H. [Department of Chemical and Biomolecular Engineering, 209 Earle Hall, Clemson University, Clemson, SC 29634-0909 (United States)

2009-05-15

This paper reports the results of the most complete conceptual study conducted to date on hydrogen production using the hybrid chlorine cycle. Three alternative process flow sheets were developed, each capable of producing hydrogen at 35 C (308 K) and 21 bar. The alternative approaches differ primarily in the way HCl is isolated and converted to hydrogen and chlorine gases. Aspen Plus trademark simulation software was used to model the unit processes, supplemented where necessary by custom Excel spreadsheets. Major equipment was sized for a 200-million kg/yr plant; feasible materials of construction were identified; fixed capital investments and variable costs were estimated. Estimated net thermal efficiencies of the flow sheets range from 30% to 36%, based on the lower heating value of the hydrogen produced. With electrical power valued at $0.05/kWh, the cost of hydrogen produced by the hybrid chlorine cycle would be at least $3/kg. These results indicate that direct electrolysis of water is a more attractive way to produce hydrogen than any presently conceived version of the hybrid chlorine cycle. (author)

Vegetation of birch and aspen forests in the Pinega State Reserve

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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.

Reaction of the antitumor antibiotic olivomycin I with aryl diazonium salts. Synthesis, cytotoxic and antiretroviral potency of 5-aryldiazenyl-6-O-deglycosyl derivatives of olivomycin I.

Science.gov (United States)

Tevyashova, Anna N; Olsufyeva, Eugenia N; Turchin, Konstantin F; Balzarini, Jan; Bykov, Eugenyi E; Dezhenkova, Lyubov G; Shtil, Alexander A; Preobrazhenskaya, Maria N

2009-07-15

The azo coupling of the antibiotic olivomycin I (1) with aryl diazonium tetrafluoroborates produced 5-aryldiazenyl-6-O-deglycosyl derivatives of 1. The structures of new compounds were confirmed by (1)H NMR and mass spectrometry analysis. A quantum-chemical study was performed to analyze the possible directions of electrophilic substitution of 1 and the easiness of 6-O-disaccharide hydrolysis in the course of azo coupling. The antiproliferative and anti-retroviral activities of novel derivatives were studied.

New exposure-based metric approach for evaluating O3 risk to North American aspen forests

International Nuclear Information System (INIS)

Percy, K.E.; Nosal, M.; Heilman, W.; Dann, T.; Sober, J.; Legge, A.H.; Karnosky, D.F.

2007-01-01

The United States and Canada currently use exposure-based metrics to protect vegetation from O 3 . Using 5 years (1999-2003) of co-measured O 3 , meteorology and growth response, we have developed exposure-based regression models that predict Populus tremuloides growth change within the North American ambient air quality context. The models comprised growing season fourth-highest daily maximum 8-h average O 3 concentration, growing degree days, and wind speed. They had high statistical significance, high goodness of fit, include 95% confidence intervals for tree growth change, and are simple to use. Averaged across a wide range of clonal sensitivity, historical 2001-2003 growth change over most of the 26 M ha P. tremuloides distribution was estimated to have ranged from no impact (0%) to strong negative impacts (-31%). With four aspen clones responding negatively (one responded positively) to O 3 , the growing season fourth-highest daily maximum 8-h average O 3 concentration performed much better than growing season SUM06, AOT40 or maximum 1 h average O 3 concentration metrics as a single indicator of aspen stem cross-sectional area growth. - A new exposure-based metric approach to predict O 3 risk to North American aspen forests has been developed

Rooting of hybrid clones of Populus tremula L. x P. tremuloides Michx. by stem cuttings derived from micropropagated plants

Energy Technology Data Exchange (ETDEWEB)

Qibin Yu [Univ. of Helsinki (Finland). Dept. of Plant Biology; Maentylae, N. [Univ. of Turku (Finland). Dept. of Biology, Plant Physiology and Molecular Biology; Salonen, M. [Finnish Forest Research Inst., Laeyliaeinen (Finland). Haapastensyrjae Breeding Station

2001-07-01

Propagation costs could be cut by replacing part of the micropropagation process with steps involving more traditional techniques. This study explored possibilities for improving existing vegetative propagation techniques for aspen using stem cuttings obtained from micropropagated plants. Vegetative propagation through stem cuttings was studied in 10 micropropagated hybrid aspen clones (Populus tremula L. x P. tremuloides Michx). Cuttings containing one axillary bud were harvested from the same donor plants twice during the growing season: the first harvest in May and the second harvest in July. Rooting percentage was correlated positively with root length, number of roots and height of cutting plant but negatively with length of rooting. The average rooting percentage was 53% in the first harvest and 27% in second harvest. Indole-3-butyric acid treatments (1.2 mM) significantly improved rooting in the second harvest, but not in the first harvest, suggesting different endogenous auxin levels in the cuttings. A significant variation for most traits related to rooting ability was found among the clones, indicating that clonal effects play an important role in the propagation of aspen. Thus, clones with a good response in shoot growth and rooting could be exploited in large-scale propagation using stem cuttings.

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

International Nuclear Information System (INIS)

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

2010-01-01

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 ∼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. - Spring leaf flush is stimulated by elevated [CO 2 ] and suppressed by elevated [O 3 ] in aspen (Populus tremuloides).

Liquefaction of aspen poplar wood

Energy Technology Data Exchange (ETDEWEB)

Eager, R L; Mathews, J F; Pepper, J M

1982-01-01

Dried and green aspen poplar wood suspended in water containing alkali catalysts was converted completely to an oil, water-soluble chemical, and gases by heating for 1 hour in the presence of CO in a rocking batch reactor. Within the ranges of parameters studied: temperature of 593-633 K; nominal reaction times of less than or equal to 1 hour; water-to-wood ratio of 0.5:1-5:1; Na/sub 2/CO/sub 3/, K/sub 2/CO/sub 3/, and NaOH catalysts; amount of catalyst 7.0-12.5%; and initial H-CO ratios of 2:1-0:1, the water-to-wood ratio was most important. Oil yields of approximately 50% with a C plus H content of approximately 80% and representing a C recovery of approximately 66% were obtained. The higher heats of combustion were 32.2-36.0 MJ/kg.

Crystal Structures of Glycosyltransferase UGT78G1 Reveal the Molecular Basis for Glycosylation and Deglycosylation of (Iso)flavonoids

Energy Technology Data Exchange (ETDEWEB)

Modolo, Luzia V.; Li, Lenong; Pan, Haiyun; Blount, Jack W.; Dixon, Richard A.; Wang, Xiaoqiang; (SRNF)

2010-09-21

The glycosyltransferase UGT78G1 from Medicago truncatula catalyzes the glycosylation of various (iso)flavonoids such as the flavonols kaempferol and myricetin, the isoflavone formononetin, and the anthocyanidins pelargonidin and cyanidin. It also catalyzes a reverse reaction to remove the sugar moiety from glycosides. The structures of UGT78G1 bound with uridine diphosphate or with both uridine diphosphate and myricetin were determined at 2.1 {angstrom} resolution, revealing detailed interactions between the enzyme and substrates/products and suggesting a distinct binding mode for the acceptor/product. Comparative structural analysis and mutagenesis identify glutamate 192 as a key amino acid for the reverse reaction. This information provides a basis for enzyme engineering to manipulate substrate specificity and to design effective biocatalysts with glycosylation and/or deglycosylation activity.

Simulation of a tubular solid oxide fuel cell stack using AspenPlusTM unit operation models

International Nuclear Information System (INIS)

Zhang, W.; Croiset, E.; Douglas, P.L.; Fowler, M.W.; Entchev, E.

2005-01-01

The design of a fuel cell system involves both optimization of the fuel cell stack and the balance of plant with respect to efficiency and economics. Many commercially available process simulators, such as AspenPlus TM , can facilitate the analysis of a solid oxide fuel cell (SOFC) system. A SOFC system may include fuel pre-processors, heat exchangers, turbines, bottoming cycles, etc., all of which can be very effectively modelled in process simulation software. The current challenge is that AspenPlus TM or any other commercial process simulators do not have a model of a basic SOFC stack. Therefore, to enable performing SOFC system simulation using one of these simulators, one must construct an SOFC stack model that can be implemented in them. The most common approach is to develop a complete SOFC model in a programming language, such as Fortran, Visual Basic or C++, first and then link it to a commercial process simulator as a user defined model or subroutine. This paper introduces a different approach to the development of a SOFC model by utilizing existing AspenPlus TM functions and existing unit operation modules. The developed ''AspenPlus TM SOFC'' model is able to provide detailed thermodynamic and parametric analyses of the SOFC operation and can easily be extended to study the entire power plant consisting of the SOFC and the balance of plant without the requirement for linking with other software. Validation of this model is performed by comparison to a Siemens-Westinghouse 100 kW class tubular SOFC stack. Sensitivity analyses of major operating parameters, such as utilization factor (U f ), current density (I c ) and steam-carbon ratio (S/C), were performed using the developed model, and the results are discussed in this paper

Evidence for an essential deglycosylation-independent activity of PNGase in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Yoko Funakoshi

Full Text Available BACKGROUND: Peptide:N-glycanase (PNGase is an enzyme which releases N-linked glycans from glycopeptides/glycoproteins. This enzyme plays a role in the ER-associated degradation (ERAD pathway in yeast and mice, but the biological importance of this activity remains unknown. PRINCIPAL FINDINGS: In this study, we characterized the ortholog of cytoplasmic PNGases, PNGase-like (Pngl, in Drosophila melanogaster. Pngl was found to have a molecular weight of approximately 74K and was mainly localized in the cytosol. Pngl lacks a CXXC motif that is critical for enzymatic activity in other species and accordingly did not appear to possess PNGase activity, though it still retains carbohydrate-binding activity. We generated microdeletions in the Pngl locus in order to investigate the functional importance of this protein in vivo. Elimination of Pngl led to a serious developmental delay or arrest during the larval and pupal stages, and surviving mutant adult males and females were frequently sterile. Most importantly, these phenotypes were rescued by ubiquitous expression of Pngl, clearly indicating that those phenotypic consequences were indeed due to the lack of functional Pngl. Interestingly, a putative "catalytic-inactive" mutant could not rescue the growth-delay phenotype, indicating that a biochemical activity of this protein is important for its biological function. CONCLUSION: Pngl was shown to be inevitable for the proper developmental transition and the biochemical properties other than deglycosylation activity is important for its biological function.

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

Science.gov (United States)

2012-10-03

....u s. In addition, an Open House will be held at the Sevier County Administrative Building in... continual maintenance, fencing is not a long term sustainable response option for protecting aspen sprouts...

Bioconcentration of zinc and cadmium in ectomycorrhizal fungi and associated aspen trees as affected by level of pollution

International Nuclear Information System (INIS)

Krpata, Doris; Fitz, Walter; Peintner, Ursula; Langer, Ingrid; Schweiger, Peter

2009-01-01

Concentrations of Zn and Cd were measured in fruitbodies of ectomycorrhizal (ECM) fungi and leaves of co-occurring accumulator aspen. Samples were taken on three metal-polluted sites and one control site. Fungal bioconcentration factors (BCF = fruitbody concentration: soil concentration) were calculated on the basis of total metal concentrations in surface soil horizons (BCF tot ) and NH 4 NO 3 -extractable metal concentrations in mineral soil (BCF lab ). When plotted on log-log scale, values of BCF decreased linearly with increasing soil metal concentrations. BCF lab for both Zn and Cd described the data more closely than BCF tot . Fungal genera differed in ZnBCF but not in CdBCF. The information on differences between fungi with respect to their predominant occurrence in different soil horizons did not improve relations of BCF with soil metal concentrations. Aspen trees accumulated Zn and Cd to similar concentrations as the ECM fungi. Apparently, the fungi did not act as an effective barrier against aspen metal uptake by retaining the metals. - Populus tremula and associated ectomycorrhizal fungi accumulate zinc and cadmium to similar concentrations

Is the wide distribution of aspen a result of its stress tolerance?

Science.gov (United States)

V. J. Lieffers; S. M. Landhausser; E. H. Hogg

2001-01-01

Populus tremuloides is distributed from drought-prone fringes of the Great Plains to extremely cold sites at arctic treeline. To occupy these conditions aspen appears to be more tolerant of stress than the other North American species of the genus Populus. Cold winters, cold soil conditions during the growing season, periodic drought, insect defoliation, and...

Soil properties and aspen development five years after compaction and forest floor removal

Science.gov (United States)

Douglas M. Stone; John D. Elioff

1998-01-01

Forest management activities that decrease soil porosity and remove organic matter have been associated with declines in site productivity. In the northern Lake States region, research is in progress in the aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forest type to determine effects of soil compaction and organic...

Prehydrolysis of aspen wood with water and with dilute aqueous sulfuric acid

Science.gov (United States)

Edward L. Springer; John F. Harris

1982-01-01

Water prehydrolysis of aspen wood was compared with 0.40% sulfuric acid prehydrolysis at a reaction temperature of 170°C. Acid prehydrolysis gave much higher yields of total anhydroxylose units in the prehydrolyzate and removed significantly less anhydroglucose from the wood than did the water treatment. At maximum yields of total anhydroxylose units in the...

The Future of Community and Personal Identity in the Coming Electronic Culture. A Report of the Annual Aspen Institute Roundtable on Information Technology (3rd, Aspen, Colorado, August 18-21, 1994).

Science.gov (United States)

Bollier, David

The 1994 Aspen Institute Roundtable on Information Technology began as a look at the changing nature of the home. In building scenarios of the "new home," the participants expressed many significant insights into issues of personal identity, community-building, and setting boundaries in our lives and environments. This report captures…

Aspen SUCROSE TRANSPORTER3 Allocates Carbon into Wood Fibers1[C][W

Science.gov (United States)

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

2013-01-01

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 13CO2 assimilation, the SUT3RNAi lines contained more 13C 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. PMID:24170204

Preparation of Highly Porous Binderless Active Carbon Monoliths from Waste Aspen Sawdust

Directory of Open Access Journals (Sweden)

Dawei Li

2014-01-01

Full Text Available Waste aspen sawdust was used as a precursor to prepare binderless active carbon monoliths (ACMs with high porosities. The ACMs were prepared by activation with H3PO4 at different activation temperatures (500 to 700 °C and retention times (1 to 3 h. Their morphologies, yields, textural properties, and microcrystalline structures were investigated using scanning electron microscopy (SEM, an analytical balance, N2 adsorption/desorption techniques, and X-ray diffraction (XRD. The results indicated that waste aspen sawdust could be successfully converted into highly porous binderless ACMs. The apparent specific surface area (SSA and yield of ACMs were in the range of 688 to 951 m2/g and 26.6 to 36.2%, respectively. Highly microporous ACMs with a micropore percentage of 91.1%, apparent specific surface area of 951 m2/g, pore volume of 0.481 mL/g, and bulk density of 0.56 g/mL could be produced by activation at 700 °C for 1 h. Increasing the activation temperature or retention time increased the specific surface area, pore volume, and turbostratic degree, but decreased the yield.

Effects of long-term (10 years) exposure to elevated CO2 and O3 on trembling Aspen carbon and nitrogen metabolism at the aspen FACE (Free-Air Carbon Dioxide Enrichment) study site

Science.gov (United States)

Rakesh Minocha; Stephanie Long; Subhash Minocha; Paula Marquardt; Neil Nelson; Mark. Kubiske

2010-01-01

This study was conducted at the Aspen Free-Air Carbon Dioxide Enrichment (FACE) experimental site, Rhinelander, WI, (USA). Since 1998, 12 experimental rings planted in 1997 underwent four different treatments: control; elevated CO2 (560 ppm); elevated O3 (1.5X ambient) and elevated CO2 (560 ppm) + O...

Changes in avian and plant communities of aspen woodlands over 12 years after livestock removal in the northwestern Great Basin

Science.gov (United States)

Earnst, Susan L.; Dobkin, David S.; Ballard, Jennifer A.

2012-01-01

Riparian and quaking aspen (Populus tremuloides) woodlands are centers of avian abundance and diversity in the western United States, but they have been affected adversely by land use practices, particularly livestock grazing. In 1990, cattle were removed from a 112,500-ha national wildlife refuge in southeastern Oregon. Thereafter, we monitored changes in vegetation and bird abundance in years 1–3 (phase 1) and 10–12 (phase 2) in 17 riparian and 9 snow-pocket aspen plots. On each 1.5-ha plot, we sampled vegetation in 6 transects. Three times during each breeding season, observers recorded all birds 50 m to each side of the plot's 150-m centerline for 25 minutes. We analyzed data with multivariate analysis of variance and paired t tests with p values adjusted for multiple comparisons. In both periods, riparian and snow-pocket aspen produced extensive regeneration of new shoots (x̄ = 2646 stems/ha and 7079 stems/ha, respectively). By phase 2, a 64% increase in medium-diameter trees in riparian stands indicated successful recruitment into the overstory, but this pattern was not seen in snow-pocket stands, where the density of trees was over 2 times greater. By phase 2 in riparian and snow-pocket stands, native forb cover had increased by 68% and 57%, respectively, mesic shrub cover had increased by 29% and 58%, and sagebrush cover had decreased by 24% and 31%. Total avian abundance increased by 33% and 39% in riparian and snow-pocket aspen, respectively, ground or understory nesters increased by 133% and 67% and overstory nesters increased by 34% and 33%. Similarly, ground or understory foragers increased by 25% and 32%, aerial foragers by 55% and 57%, and overstory foragers by 66% and 43%. We interpreted the substantial regeneration of aspen shoots, increased densities of riparian forbs and shrubs, and increased avian abundances as a multitrophic-level response to the total removal of livestock and as substantial movement toward recovery of biological integrity.

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.

Continental-scale assessment of genetic diversity and population structure in quaking aspen (Populus tremuloides)

Science.gov (United States)

Colin M. Callahan; Carol A. Rowe; Ronald J. Ryel; John D. Shaw; Michael D. Madritch; Karen E. Mock

2013-01-01

Aspen populations in the south-western portion of the range are consistent with expectations for a historically stable edge, with low within-population diversity, significant geographical population structuring, and little evidence of northward expansion. Structuring within the southwestern cluster may result from distinct gene pools separated during the Pleistocene...

An enzymatic deglycosylation scheme enabling identification of core fucosylated N-glycans and O-glycosylation site mapping of human plasma proteins

DEFF Research Database (Denmark)

Hägglund, Per; Matthiesen, R.; Elortza, F.

2007-01-01

and N-acetyl-β-glucosaminidase) are also included. The two strategies were here applied to identify 103 N-glycosylation sites in the Cohn IV fraction of human plasma. In addition, Endo D/H digestion uniquely enabled identification of 23 fucosylated N-glycosylation sites. Several O-glycosylated peptides......, thereby reducing the complexity and facilitating glycosylation site determinations. Here, we have used two different enzymatic deglycosylation strategies for N-glycosylation site analysis. (1) Removal of entire N-glycan chains by peptide- N-glycosidase (PNGase) digestion, with concomitant deamidation...... of the released asparagine residue. The reaction is carried out in H218O to facilitate identification of the formerly glycosylated peptide by incorporatation of 18O into the formed aspartic acid residue. (2) Digestion with two endo-β- N-acetylglucosaminidases (Endo D and Endo H) that cleave the glycosidic bond...

Deglycosylation of serum vitamin D3-binding protein leads to immunosuppression in cancer patients.

Science.gov (United States)

Yamamoto, N; Naraparaju, V R; Asbell, S O

1996-06-15

Serum vitamin D3-binding protein (Gc protein) can be converted by beta-galactosidase of B cells and sialidase of T cells to a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar moiety. Thus, Gc protein is the precursor of the macrophage activating factor (MAF). Treatment of Gc protein with immobilized beta-galactosidase and sialidase generates an extremely high titered MAF, Gc-MAF. When peripheral blood monocytes/macrophages of 52 patients bearing various types of cancer were incubated with 100 pg/ml of GcMAF, the monocytes/macrophages of all patients were efficiently activated. However, the MAF precursor activity of patient plasma Gc protein was found to be severely reduced in about 25% of this patient population. About 45% of the patients had moderately reduced MAF precursor activities. Loss of the precursor activity was found to be due to deglycosylation of plasma Gc protein by alpha-N-acetylgalactosaminidase detected in the patient's bloodstream. The source of the enzyme appeared to be cancerous cells. Radiation therapy decreased plasma alpha-N-acetylgalactosaminidase activity with concomitant increase of precursor activity. This implies that radiation therapy decreases the number of cancerous cells capable of secreting alpha-N-acetylgalactosaminidase. Both alpha-N-acetylgalactosaminidase activity and MAF precursor activity of Gc protein in patient bloodstream can serve as diagnostic and prognostic indices.

Organo-mineral interactions promote greater soil organic carbon stability under aspen in semi-arid montane forests in Utah

Science.gov (United States)

Van Miegroet, H.; Roman Dobarco, M.

2014-12-01

Forest species influence soil organic carbon (SOC) storage through litter input, which in interaction with soil microclimate, texture and mineralogy, lead to different SOC stabilization and storage patterns. We sampled mineral soil (0-15 cm) across the ecotone between aspen (Populus tremuloides) and mixed conifers stands (Abies lasiocarpa and Pseudotsuga menziesii) in semi-arid montane forests from Utah, to investigate the influence of vegetation vs. site characteristics on SOC stabilization, storage and chemistry. SOC was divided into light fraction (LF), mineral-associated SOC in the silt and clay fraction (MoM), and a dense subfraction > 53 μm (SMoM) using wet sieving and electrostatic attraction. SOC decomposability and solubility was derived from long term laboratory incubations and hot water extractions (HWE). Fourier transform infrared spectroscopy (FTIR) was used to study differences in chemical functional groups in LF and MoM. Vegetation cover did not affect SOC storage (47.0 ± 16.5 Mg C ha-1), SOC decomposability (cumulative CO2-C release of 93.2 ± 65.4 g C g-1 C), or SOC solubility (9.8 ± 7.2 mg C g-1 C), but MoM content increased with presence of aspen [pure aspen (31.2 ± 15.1 Mg C ha-1) > mixed (25.7 ± 8.8 Mg C ha-1) > conifer (22.8 ± 9.0 Mg C ha-1)]. Organo-mineral complexes reduced biological availability of SOC, indicated by the negative correlation between silt+clay (%) and decomposable SOC per gram of C (r = -0.48, p = 0.001) or soluble SOC (r = -0.59, p plant or microbial origin. FTIR spectra clustered by sites with similar parent material rather than by vegetation cover. This suggests that initial differences in litter chemistry between aspen and conifers converged into similar MoM chemistry within sites.

Barrier to gene flow between two ecologically divergent Populus species, P. alba (white poplar) and P. tremula (European aspen): the role of ecology and life history in gene introgression.

Science.gov (United States)

Lexer, C; Fay, M F; Joseph, J A; Nica, M-S; Heinze, B

2005-04-01

The renewed interest in the use of hybrid zones for studying speciation calls for the identification and study of hybrid zones across a wide range of organisms, especially in long-lived taxa for which it is often difficult to generate interpopulation variation through controlled crosses. Here, we report on the extent and direction of introgression between two members of the "model tree" genus Populus: Populus alba (white poplar) and Populus tremula (European aspen), across a large zone of sympatry located in the Danube valley. We genotyped 93 hybrid morphotypes and samples from four parental reference populations from within and outside the zone of sympatry for a genome-wide set of 20 nuclear microsatellites and eight plastid DNA restriction site polymorphisms. Our results indicate that introgression occurs preferentially from P. tremula to P. alba via P. tremula pollen. This unidirectional pattern is facilitated by high levels of pollen vs. seed dispersal in P. tremula (pollen/seed flow = 23.9) and by great ecological opportunity in the lowland floodplain forest in proximity to P. alba seed parents, which maintains gene flow in the direction of P. alba despite smaller effective population sizes (N(e)) in this species (P. alba N(e)c. 500-550; P. tremula N(e)c. 550-700). Our results indicate that hybrid zones will be valuable tools for studying the genetic architecture of the barrier to gene flow between these two ecologically divergent Populus species.

The effect of warming and enhanced ultraviolet radiation on gender-specific emissions of volatile organic compounds from European aspen

Energy Technology Data Exchange (ETDEWEB)

Maja, Mengistu M., E-mail: mengistu.maja@uef.fi [University of Eastern Finland, Department of Environmental Science, P.O.Box 1627, 70211 Kuopio (Finland); Kasurinen, Anne; Holopainen, Toini [University of Eastern Finland, Department of Environmental Science, P.O.Box 1627, 70211 Kuopio (Finland); Julkunen-Tiitto, Riitta [University of Eastern Finland, Department of Biology, P.O. Box 111, 80101 Joensuu (Finland); Holopainen, Jarmo K. [University of Eastern Finland, Department of Environmental Science, P.O.Box 1627, 70211 Kuopio (Finland)

2016-03-15

Different environmental stress factors often occur together but their combined effects on plant secondary metabolism are seldom considered. We studied the effect of enhanced ultraviolet (UV-B) (31% increase) radiation and temperature (ambient + 2 °C) singly and in combination on gender-specific emissions of volatile organic compounds (VOCs) from 2-year-old clones of European aspen (Populus tremula L.). Plants grew in 36 experimental plots (6 replicates for Control, UV-A, UV-B, T, UV-A + T and UV-B + T treatments), in an experimental field. VOCs emitted from shoots were sampled from two (1 male and 1 female) randomly selected saplings (total of 72 saplings), per plot on two sampling occasions (June and July) in 2014. There was a significant UV-B × temperature interaction effect on emission rates of different VOCs. Isoprene emission rate was increased due to warming, but warming also modified VOC responses to both UV-A and UV-B radiation. Thus, UV-A increased isoprene emissions without warming, whereas UV-B increased emissions only in combination with warming. Warming-modified UV-A and UV-B responses were also seen in monoterpenes (MTs), sesquiterpenes (SQTs) and green leaf volatiles (GLVs). MTs showed also a UV × gender interaction effect as females had higher emission rates under UV-A and UV-B than males. UV × gender and T × gender interactions caused significant differences in VOC blend as there was more variation (more GLVs and trans-β-caryophyllene) in VOCs from female saplings compared to male saplings. VOCs from the rhizosphere were also collected from each plot in two exposure seasons, but no significant treatment effects were observed. Our results suggest that simultaneous warming and elevated-UV-radiation increase the emission of VOCs from aspen. Thus the contribution of combined environmental factors on VOC emissions may have a greater impact to the photochemical reactions in the atmosphere compared to the impact of individual factors acting alone

The effect of warming and enhanced ultraviolet radiation on gender-specific emissions of volatile organic compounds from European aspen

International Nuclear Information System (INIS)

Maja, Mengistu M.; Kasurinen, Anne; Holopainen, Toini; Julkunen-Tiitto, Riitta; Holopainen, Jarmo K.

2016-01-01

Different environmental stress factors often occur together but their combined effects on plant secondary metabolism are seldom considered. We studied the effect of enhanced ultraviolet (UV-B) (31% increase) radiation and temperature (ambient + 2 °C) singly and in combination on gender-specific emissions of volatile organic compounds (VOCs) from 2-year-old clones of European aspen (Populus tremula L.). Plants grew in 36 experimental plots (6 replicates for Control, UV-A, UV-B, T, UV-A + T and UV-B + T treatments), in an experimental field. VOCs emitted from shoots were sampled from two (1 male and 1 female) randomly selected saplings (total of 72 saplings), per plot on two sampling occasions (June and July) in 2014. There was a significant UV-B × temperature interaction effect on emission rates of different VOCs. Isoprene emission rate was increased due to warming, but warming also modified VOC responses to both UV-A and UV-B radiation. Thus, UV-A increased isoprene emissions without warming, whereas UV-B increased emissions only in combination with warming. Warming-modified UV-A and UV-B responses were also seen in monoterpenes (MTs), sesquiterpenes (SQTs) and green leaf volatiles (GLVs). MTs showed also a UV × gender interaction effect as females had higher emission rates under UV-A and UV-B than males. UV × gender and T × gender interactions caused significant differences in VOC blend as there was more variation (more GLVs and trans-β-caryophyllene) in VOCs from female saplings compared to male saplings. VOCs from the rhizosphere were also collected from each plot in two exposure seasons, but no significant treatment effects were observed. Our results suggest that simultaneous warming and elevated-UV-radiation increase the emission of VOCs from aspen. Thus the contribution of combined environmental factors on VOC emissions may have a greater impact to the photochemical reactions in the atmosphere compared to the impact of individual factors acting alone

2012 Aspen Winter Conference New Paradigms for Low-Dimensional Electronic Materials, February 5-10, 2012

Energy Technology Data Exchange (ETDEWEB)

Moore, Joel; Rabe, Karin; Nayak, Chetan; Troyer, Matthias

2012-05-01

Aspen Center for Physics Project Summary DOE Budget Period: 10/1/2011 to 9/30/2012 Contract # DE-SC0007479 New Paradigms for Low-Dimensional Electronic Materials The 2012 Aspen Winter Conference on Condensed Matter Physics was held at the Aspen Center for Physics from February 5 to 10, 2012. Seventy-four participants from seven countries, and several universities and national labs attended the workshop titled, New Paradigms for Low-Dimensional Electronic Materials. There were 34 formal talks, and a number of informal discussions held during the week. Talks covered a variety of topics related to DOE BES priorities, including, for example, advanced photon techniques (Hasan, Abbamonte, Orenstein, Shen, Ghosh) and predictive theoretical modeling of materials properties (Rappe, Pickett, Balents, Zhang, Vanderbilt); the full conference schedule is provided with this report. The week's events included a public lecture (Quantum Matters given by Chetan Nayak from Microsoft Research) and attended by 234 members of the public, and a physics caf© geared for high schoolers that is a discussion with physicists conducted by Kathryn Moler (Stanford University) and Andrew M. Rappe (University of Pennsylvania) 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 Joel Moore (University of California Berkeley), Chetan Nayak (Microsoft Research), Karin Rabe (Rutgers University), and Matthias Troyer (ETH Zurich). Two organizers who did not attend the conference were Gabriel Aeppli (University College London & London Centre for Nanotechnology) and Andrea Cavalleri (Oxford University & Max Planck Hamburg).

Microscale Ocean Biophysics, Aspen Center for Physics: January 11-16 2015

Science.gov (United States)

2017-04-19

dissolved   organic  matter  persist  in  the  deep  ocean:  Is  the  solution   dilution ?”     8.45  –  Kwangmin  Son...AUTHORS 7. PERFORMING ORGANIZATION NAMES AND ADDRESSES 15. SUBJECT TERMS b. ABSTRACT 2. REPORT TYPE 17. LIMITATION OF ABSTRACT 15. NUMBER OF PAGES...Microscale Ocean Biophysics, Aspen Center for Physics, January 11-16, 2015 Microscopic organisms control ocean processes at global scales. However

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. © 2016 American Society for Parenteral and Enteral Nutrition.

Effect of steam treatment on the hydrolysis of aspen by commerical enzymes

Energy Technology Data Exchange (ETDEWEB)

Macdonald, D G; Mathews, J F

1979-06-01

Steam treatment renders aspen wood more susceptible to hydrolysis by commerical enzyme preparations such as the Onozuka variety. The main products of enzymatic hydrolysis are glucose, xylose, and xylobiose. Cellobiose may have been another product but it could not be measured due to interference by lactose, a sugar found in the enzyme. The hemicellulose fraction of the wood is relatively more rapidly hydrolyzed by the enzymes than the cellulose fraction.

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

Science.gov (United States)

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

2006-01-01

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...

Effect of citric acid modification of aspen wood on sorption of copper ion

Science.gov (United States)

James D. McSweeny; Roger M. Rowell; Soo Hong Min

2006-01-01

Milled aspen wood was thermochemically modified with citric acid for the purpose of improving the copper (Cu2+) ion sorption capacity of the wood when tested in 24-hour equilibrium batch tests. The wood-citric acid adducts provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ ion uptake of the modified wood compared with that...

Enhanced model for integrated simulation of an entrained bed gasifier implemented as Aspen Hysys extension

Energy Technology Data Exchange (ETDEWEB)

Perez-Fortes, M; Bojarski, A; Ferrer-Nadal, S; Kopanos, G; Mitta, N; Pinilla, C A; Nougues, J M; Velo, E; Puigjaner, L [Universitat Politecnica de Catalunya, Barcelona (Spain). Dept. of Chemical Engineering-CEPIMA

2007-07-01

In this work an enhanced mathematical model of an entrained bed gasifier has been developed for improved synthesis gas production. The gasification model considers five stages: pyrolysis, volatiles combustion, char combustion, gasification and a final gas equilibrium zone. Mathematical simulations are carried out to help finding out feasible operating conditions of the process to achieve improved process performance. Visual Basic (VB) is tested as tool for modelling, by using the Aspen Hysys Extension (AHE) interface standards. This standard provides a suitable environment for this purpose, since it allows the creation of completely custom modules which are easy to plug and use thus facilitating the handling of complex models ready to interact with commercial simulation platforms. In this work, integration of different models is accomplished in Aspen Hysys (AH), which provides the basic connectivity within models components, and the thermodynamic framework needed. The integrated modules simulation environment platform uses data from ELCOGAS for validation purposes with excellent preliminary results. 9 refs., 2 figs.

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.

Urbanization-related changes in European aspen (Populus tremula L.): Leaf traits and litter decomposition

International Nuclear Information System (INIS)

Nikula, Suvi; Vapaavuori, Elina; Manninen, Sirkku

2010-01-01

We investigated foliar and litter responses of European aspen (Populus tremula L.) to urbanization, including factors such as increased temperature, moisture stress and nitrogen (N) deposition. Leaf samples were collected in 2006-2008 from three urban and three rural forest stands in the Helsinki Metropolitan Area, southern Finland, and reciprocal litter transplantations were established between urban and rural sites. Urban leaves exhibited a higher amount of epicuticular waxes and N concentration, and a lower C:N ratio than rural ones, but there was no difference in specific leaf area. Urban litter had a slightly higher N concentration, lower concentrations of lignin and total phenolics, and was more palatable to a macrofaunal decomposer. Moreover, litter decay was faster at the urban site and for urban litter. Urbanization thus resulted in foliar acclimatization in terms of increased amount of epicuticular waxes, as well as in accelerated decomposition of the N-richer leaf litter. - Urbanization can modify leaf traits of aspen and accelerate litter decomposition through changes in litter traits as well as in environmental conditions at the decomposition site.

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…

Factors affecting fall down rates of dead aspen (Populus tremuloides) biomass following severe drought in west-central Canada.

Science.gov (United States)

Ted Hogg, Edward H; Michaelian, Michael

2015-05-01

Increases in mortality of trembling aspen (Populus tremuloides Michx.) have been recorded across large areas of western North America following recent periods of exceptionally severe drought. The resultant increase in standing, dead tree biomass represents a significant potential source of carbon emissions to the atmosphere, but the timing of emissions is partially driven by dead-wood dynamics which include the fall down and breakage of dead aspen stems. The rate at which dead trees fall to the ground also strongly influences the period over which forest dieback episodes can be detected by aerial surveys or satellite remote sensing observations. Over a 12-year period (2000-2012), we monitored the annual status of 1010 aspen trees that died during and following a severe regional drought within 25 study areas across west-central Canada. Observations of stem fall down and breakage (snapping) were used to estimate woody biomass transfer from standing to downed dead wood as a function of years since tree death. For the region as a whole, we estimated that >80% of standing dead aspen biomass had fallen after 10 years. Overall, the rate of fall down was minimal during the year following stem death, but thereafter fall rates followed a negative exponential equation with k = 0.20 per year. However, there was high between-site variation in the rate of fall down (k = 0.08-0.37 per year). The analysis showed that fall down rates were positively correlated with stand age, site windiness, and the incidence of decay fungi (Phellinus tremulae (Bond.) Bond. and Boris.) and wood-boring insects. These factors are thus likely to influence the rate of carbon emissions from dead trees following periods of climate-related forest die-off episodes. © 2014 Her Majesty the Queen in Right of Canada Global Change Biology © 2014 John Wiley & Sons Ltd Reproduced with the permission of the Minister of Natural Resources Canada.

Polypropylene /Aspen/ liquid polybutadienes composites: maximization of impact strength, tensile and modulus by statistical experimental design

Czech Academy of Sciences Publication Activity Database

Kokta, B. V.; Fortelný, Ivan; Kruliš, Zdeněk; Horák, Zdeněk; Michálková, Danuše

2005-01-01

Roč. 99, - (2005), s. 10-11 ISSN 0009-2770. [International Conference on Polymeric Materials in Automotive , Slovak Rubber Conference /17./. 10.5.2005-12.5.2005, Bratislava] Institutional research plan: CEZ:AV0Z40500505 Keywords : polypropylene * Aspen-PP composite Subject RIV: CD - Macromolecular Chemistry

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...

Utilization of steam- and explosion-decompressed aspen wood by some anaerobes

Energy Technology Data Exchange (ETDEWEB)

Khan, A W; Asther, M; Giuliano, C

1984-01-01

Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as a substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes less than 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also suitable for the single-step conversion of cellulose to EtOH using cocultures consisting of cellulolytic and EtOH-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes.

Converting partially-stocked aspen stands to fully-stocked stands in the Lake States: an economic analysis.

Science.gov (United States)

Jeffrey T. Olson; Allen L. Lundgren

1978-01-01

The 1968 Wisconsin Forest Survey showed large areas of aspen type that are not considered fully stocked. The economic feasibility of converting partially-stocked stands to full stocking is examined, and a rule presented for determining when a partially-stocked stand should be harvested to maximize its present value.

Root growth and physiology of potted and field-grown trembling aspen exposed to tropospheric ozone

Science.gov (United States)

M.D. Coleman; R.E. Dickson; J.G. Isebrands; D.F. Karnosky

1996-01-01

We studied root growth and respiration of potted plants and field-grown aspen trees (Populus tremuloides Michx.) exposed to ambient or twice-ambient ozone. Root dry weight of potted plants decreased up to 45% after 12 weeks of ozone treatment, and root system respiration decreased by 27%. The ozone-induced decrease in root system respiration of...

ASPEN-AND-ESPEN: A postacute-care comparison of the basic definition of malnutrition from the American Society of Parenteral and Enteral Nutrition and Academy of Nutrition and Dietetics with the European Society for Clinical Nutrition and Metabolism definition.

Science.gov (United States)

Sánchez-Rodríguez, Dolores; Marco, Ester; Ronquillo-Moreno, Natalia; Maciel-Bravo, Liev; Gonzales-Carhuancho, Abel; Duran, Xavier; Guillén-Solà, Anna; Vázquez-Ibar, Olga; Escalada, Ferran; Muniesa, Josep M

2018-01-25

The aim of this study was to assess the prevalence of malnutrition by applying the ASPEN/AND definition and the ESPEN consensus definition in a postacute-care population, and secondly, to determine the metrological properties of the set of six clinical characteristics that constitute the ASPEN/AND basic diagnosis, compared to the ESPEN consensus, based mostly on objective anthropometric measurements. Prospective study of 84 consecutive deconditioned older inpatients (85.4 ± 6.2; 59.5% women) admitted for rehabilitation in postacute care. ASPEN/AND diagnosis of malnutrition was considered in presence of at least two of the following: low energy intake, fluid accumulation, diminished handgrip strength, and loss of weight, muscle mass, or subcutaneous fat. Sensitivity, specificity, positive and negative predictive values, accuracy, likelihood ratios, and kappa statistics were calculated for ASPEN/AND criteria and compared with ESPEN consensus. The prevalence of malnutrition by ASPEN/AND criteria was 63.1% and by ESPEN consensus, 20.2%; both diagnoses were associated with significantly longer length of stay, but the ESPEN definition was significantly associated with poorer functional outcomes after the rehabilitation program. Compared to ESPEN consensus, ASPEN/AND diagnosis showed fair validity (sensitivity = 94.1%; specificity = 44.8%); kappa statistic was 2.217. Applying the ASPEN/AND definition obtained a higher prevalence of malnutrition in a postacute-care population than was identified by the ESPEN definition. ASPEN/AND criteria had fair validity and agreement compared with the ESPEN definition. A simple, evidence-based, unified malnutrition definition might improve geriatric care. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Variable performance of outbreak defoliators on aspen clones exposed to elevated CO2 and O3

Science.gov (United States)

Daniel A. Herms; William J. Mattson; David N. Karowe; Mark D. Coleman; Terry M. Trier; Bruce A. Birr; J. G. Isebrands

1996-01-01

Increasing atmospheric concentrations of ozone and CO2 affect many aspects of tree physiology. However, their effects on tree resistance to insects have received relatively little attention. The objectives of this study were to test the effects of elevated CO2 and ozone on the resistance of three quaking aspen (...

Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks

Science.gov (United States)

Reinikainen, Michael; D’Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

2014-01-01

Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain

Estimation of Physical Properties for Hydrogen Isotopes Using Aspen Plus Simulator

International Nuclear Information System (INIS)

Cho, Jung Ho; Yun, Sei Hun; Cho, Seung Yon; Chang, Min Ho; Kang, Hyun Goo; Jung, Ki Jung; Kim, Dong Min

2009-01-01

Hydrogen isotopes are H 2 , HD, D 2 , H 2 , HD, D 2 , HT, DT and T 2 . Among the hydrogen isotopes, the physical properties of H2, HD and D+2 are included in the Aspen Plus, however HT, D T and T 2 are not included. In this study, various thermodynamic properties were estimated for six components of isotopes by use of the fixed properties and temperature-dependent properties. To estimate thermodynamic properties, Soave modified Redlich-Kwong equation of state and Aspenplus simulator was used. The results were verified and compared with by PRO/II with PROVISION of Invensys

Mechanistic simulation of batch acetone-butanol-ethanol (ABE) fermentation with in situ gas stripping using Aspen Plus™.

Science.gov (United States)

Darkwah, Kwabena; Nokes, Sue E; Seay, Jeffrey R; Knutson, Barbara L

2018-05-22

Process simulations of batch fermentations with in situ product separation traditionally decouple these interdependent steps by simulating a separate "steady state" continuous fermentation and separation units. In this study, an integrated batch fermentation and separation process was simulated for a model system of acetone-butanol-ethanol (ABE) fermentation with in situ gas stripping, such that the fermentation kinetics are linked in real-time to the gas stripping process. A time-dependent cell growth, substrate utilization, and product production is translated to an Aspen Plus batch reactor. This approach capitalizes on the phase equilibria calculations of Aspen Plus to predict the effect of stripping on the ABE fermentation kinetics. The product profiles of the integrated fermentation and separation are shown to be sensitive to gas flow rate, unlike separate steady state fermentation and separation simulations. This study demonstrates the importance of coupled fermentation and separation simulation approaches for the systematic analyses of unsteady state processes.

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.

Soil Organic Carbon Storage and Stability in the Aspen-Conifer Ecotone in Montane Forests in Utah, USA

Directory of Open Access Journals (Sweden)

Mercedes Román Dobarco

2014-04-01

Full Text Available To assess the potential impact of conifer encroachment on soil organic carbon (SOC dynamics and storage in montane aspen-conifer forests from the interior western US, we sampled mineral soils (0–15 cm across the aspen-conifer ecotones in southern and northern Utah and quantified total SOC stocks, stable SOC (i.e., mineral-associated SOC (MoM, labile SOC (i.e., light fraction (LF, decomposable (CO2 release during long-term aerobic incubations and soluble SOC (hot water extractable organic carbon (HWEOC. Total SOC storage (47.0 ± 16.5 Mg C ha−1 and labile SOC as LF (14.0 ± 7.10 Mg C ha−1, SOC decomposability (cumulative released CO2-C of 5.6 ± 3.8 g C g−1 soil or HWEOC (0.6 ± 0.6 mg C g−1 soil did not differ substantially with vegetation type, although a slight increase in HWEOC was observed with increasing conifer in the overstory. There were statistically significant differences (p = 0.035 in stable MoM storage, which was higher under aspen (31.2 ± 15.1 Mg C ha−1 than under conifer (22.8 ± 9.0 Mg C ha−1, with intermediate values under mixed (25.7 ± 8.8 Mg C ha−1. Texture had the greatest impact on SOC distribution among labile and stable fractions, with increasing stabilization in MoM and decreasing bio-availability of SOC with increasing silt + clay content. Only at lower silt + clay contents (40%–70% could we discern the influence of vegetation on MoM content. This highlights the importance of chemical protection mechanisms for long-term C sequestration.

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

A system for predicting the amount of Phellinus (Fomes) igniarius rot in trembling aspen stands

Science.gov (United States)

Robert L. Anderson; Arthur L. Jr. Schipper

1978-01-01

The occurrence of Phellinus (Fomes) igniarius white trunk rot in 45- to 50-year-old trembling aspen stands can be predicted by applying a constant to the stand basal area with P. igniarius conks to estimate the total basal area with P. igniarius rot. Future decay projections can be made by reapplying the basal area of hidden decay for each 6 years projected. This paper...

Aspen Simulation of Diesel-Biodiesel Blends Combustion

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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.

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...

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

Science.gov (United States)

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

2007-01-01

Three model communities of trembling aspen (monoculture, and mixed with either paper birch or sugar maple) were grown for seven years in elevated atmospheric CO2 and O3 using Free Air CO2 Enrichment (FACE) technology. We utilized trends in species' importance, calculated as an index of volume...

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...

A hybrid solar and chemical looping combustion system for solar thermal energy storage

International Nuclear Information System (INIS)

Jafarian, Mehdi; Arjomandi, Maziar; Nathan, Graham J.

2013-01-01

Highlights: ► A novel solar–CLC hybrid system is proposed which integrates a CLC with solar thermal energy. ► The oxygen carrier particles are used as storage medium for thermal energy storage. ► A solar cavity reactor is proposed for fuel reactor. ► The absorbed solar energy is stored in the particles to produce a base heat load. -- Abstract: A novel hybrid of a solar thermal energy and a chemical looping combustion (CLC) system is proposed here, which employs the oxygen carrier particles in a CLC system to provide diurnal thermal energy storage for concentrated solar thermal energy. In taking advantage of the chemical and sensible energy storage systems that are an inherent part of a CLC system, this hybrid offers potential to achieve cost effective, base load power generation for solar energy. In the proposed system, three reservoirs have been added to a conventional CLC system to allow storage of the oxygen carrier particles, while a cavity solar receiver has been chosen for the fuel reactor. The performance of the system is evaluated using ASPEN PLUS software, with the model being validated using independent simulation result reported previously. Operating temperature, solar efficiency, solar fraction, exergy efficiency and the fraction of the solar thermal energy stored for a based load power generation application are reported.

Acute O3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment

Science.gov (United States)

Joseph N.T. Darbah; Wendy S. Jones; Andrew J. Burton; John Nagy; Mark E. Kubiske

2011-01-01

We studied the effect of high ozone (O3) concentration (110-490 nmol mol-1) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O3 pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine...

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...

Enhanced Production of Two Bioactive Isoflavone Aglycones in Astragalus membranaceus Hairy Root Cultures by Combining Deglycosylation and Elicitation of Immobilized Edible Aspergillus niger.

Science.gov (United States)

Jiao, Jiao; Gai, Qing-Yan; Niu, Li-Li; Wang, Xi-Qing; Guo, Na; Zang, Yu-Ping; Fu, Yu-Jie

2017-10-18

A cocultivation system of Astragalus membranaceus hairy root cultures (AMHRCs) and immobilized food-grade fungi was established for the enhanced production of calycosin (CA) and formononetin (FO). The highest accumulations of CA (730.88 ± 63.72 μg/g DW) and FO (1119.42 ± 95.85 μg/g DW) were achieved in 34 day-old AMHRCs cocultured with immobilized A. niger (IAN) for 54 h, which were 7.72- and 18.78-fold higher than CA and FO in nontreated control, respectively. IAN deglycosylation could promote the formation of CA and FO by conversion of their glycoside precursors. IAN elicitation could intensify the generation of endogenous signal molecules involved in plant defense response, which contributed to the significantly up-regulated expression of genes in CA and FO biosynthetic pathway. Overall, the coupled culture of IAN and AMHRCs offered a promising and effective in vitro approach to enhance the production of two health-promoting isoflavone aglycones for possible nutraceutical and pharmaceutical uses.

Effects of hybridization and evolutionary constraints on secondary metabolites: the genetic architecture of phenylpropanoids in European populus species.

Science.gov (United States)

Caseys, Celine; Stritt, Christoph; Glauser, Gaetan; Blanchard, Thierry; Lexer, Christian

2015-01-01

The mechanisms responsible for the origin, maintenance and evolution of plant secondary metabolite diversity remain largely unknown. Decades of phenotypic studies suggest hybridization as a key player in generating chemical diversity in plants. Knowledge of the genetic architecture and selective constraints of phytochemical traits is key to understanding the effects of hybridization on plant chemical diversity and ecological interactions. Using the European Populus species P. alba (White poplar) and P. tremula (European aspen) and their hybrids as a model, we examined levels of inter- and intraspecific variation, heritabilities, phenotypic correlations, and the genetic architecture of 38 compounds of the phenylpropanoid pathway measured by liquid chromatography and mass spectrometry (UHPLC-MS). We detected 41 quantitative trait loci (QTL) for chlorogenic acids, salicinoids and flavonoids by genetic mapping in natural hybrid crosses. We show that these three branches of the phenylpropanoid pathway exhibit different geographic patterns of variation, heritabilities, and genetic architectures, and that they are affected differently by hybridization and evolutionary constraints. Flavonoid abundances present high species specificity, clear geographic structure, and strong genetic determination, contrary to salicinoids and chlorogenic acids. Salicinoids, which represent important defence compounds in Salicaceae, exhibited pronounced genetic correlations on the QTL map. Our results suggest that interspecific phytochemical differentiation is concentrated in downstream sections of the phenylpropanoid pathway. In particular, our data point to glycosyltransferase enzymes as likely targets of rapid evolution and interspecific differentiation in the 'model forest tree' Populus.

Effects of hybridization and evolutionary constraints on secondary metabolites: the genetic architecture of phenylpropanoids in European populus species.

Directory of Open Access Journals (Sweden)

Celine Caseys

Full Text Available The mechanisms responsible for the origin, maintenance and evolution of plant secondary metabolite diversity remain largely unknown. Decades of phenotypic studies suggest hybridization as a key player in generating chemical diversity in plants. Knowledge of the genetic architecture and selective constraints of phytochemical traits is key to understanding the effects of hybridization on plant chemical diversity and ecological interactions. Using the European Populus species P. alba (White poplar and P. tremula (European aspen and their hybrids as a model, we examined levels of inter- and intraspecific variation, heritabilities, phenotypic correlations, and the genetic architecture of 38 compounds of the phenylpropanoid pathway measured by liquid chromatography and mass spectrometry (UHPLC-MS. We detected 41 quantitative trait loci (QTL for chlorogenic acids, salicinoids and flavonoids by genetic mapping in natural hybrid crosses. We show that these three branches of the phenylpropanoid pathway exhibit different geographic patterns of variation, heritabilities, and genetic architectures, and that they are affected differently by hybridization and evolutionary constraints. Flavonoid abundances present high species specificity, clear geographic structure, and strong genetic determination, contrary to salicinoids and chlorogenic acids. Salicinoids, which represent important defence compounds in Salicaceae, exhibited pronounced genetic correlations on the QTL map. Our results suggest that interspecific phytochemical differentiation is concentrated in downstream sections of the phenylpropanoid pathway. In particular, our data point to glycosyltransferase enzymes as likely targets of rapid evolution and interspecific differentiation in the 'model forest tree' Populus.

Moderation of [CO2]-induced gas exchange responses by elevated tropospheric O3 in trembling aspen and sugar maple

Science.gov (United States)

Pooja Sharma; Anu Sober; Jaak Sober; Gopi P. Podila; Mark E. Kubiske; William J. Mattson; Judson G. Isebrands; David F. Karnosky

2003-01-01

The greenhouse gases CO2 and 03 are increasing in the earth's atmosphere. Little is known about long-term impacts of these two co-occurring gases on forest trees. We have been examining the impacts of these two gases on the physiology and growth of trembling aspen (Populus tremuloides) and sugar...

Modelling growth-competition relationships in trembling aspen and white spruce mixed boreal forests of Western Canada.

Science.gov (United States)

Huang, Jian-Guo; Stadt, Kenneth J; Dawson, Andria; Comeau, Philip G

2013-01-01

We examined the effect of competition on stem growth of Picea glauca and Populus tremuloides in boreal mixedwood stands during the stem exclusion stage. We combined traditional approaches of collecting competition data with dendrochronology to provide retrospective measurements of stem diameter growth. Several competition indices including stand basal area (BA), the sum of stem diameter at breast height (SDBH), and density (N) for the broadleaf and coniferous species, as well as similar indices considering only trees with diameters greater than each subject (BAGR, SDBHGR, and NGR), were evaluated. We used a nonlinear mixed model to characterize the basal area increment over the past 5, 10, 15, 20, 25, 30, and 35 years as a function of growth of nearby dominant trees, the size of the subject trees, deciduous and coniferous competition indices, and ecoregions. SDBHGR and BAGR were better predictors for spruce, and SDBHGR and NGR were better for aspen, respectively, than other indices. Results showed strongest correlations with long-term stem growth, as the best models integrated growth for 10-25 years for aspen and ≥ 25 for spruce. Our model demonstrated a remarkable capability (adjusted R(2)>0.67) to represent this complex variation in growth as a function of site, size and competition.

Modelling growth-competition relationships in trembling aspen and white spruce mixed boreal forests of Western Canada.

Directory of Open Access Journals (Sweden)

Jian-Guo Huang

Full Text Available We examined the effect of competition on stem growth of Picea glauca and Populus tremuloides in boreal mixedwood stands during the stem exclusion stage. We combined traditional approaches of collecting competition data with dendrochronology to provide retrospective measurements of stem diameter growth. Several competition indices including stand basal area (BA, the sum of stem diameter at breast height (SDBH, and density (N for the broadleaf and coniferous species, as well as similar indices considering only trees with diameters greater than each subject (BAGR, SDBHGR, and NGR, were evaluated. We used a nonlinear mixed model to characterize the basal area increment over the past 5, 10, 15, 20, 25, 30, and 35 years as a function of growth of nearby dominant trees, the size of the subject trees, deciduous and coniferous competition indices, and ecoregions. SDBHGR and BAGR were better predictors for spruce, and SDBHGR and NGR were better for aspen, respectively, than other indices. Results showed strongest correlations with long-term stem growth, as the best models integrated growth for 10-25 years for aspen and ≥ 25 for spruce. Our model demonstrated a remarkable capability (adjusted R(2>0.67 to represent this complex variation in growth as a function of site, size and competition.

Simulation of SOFCs based power generation system using Aspen

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Pianko-Oprych Paulina

2017-12-01

Full Text Available This study presents a thermodynamic Aspen simulation model for Solid Oxide Fuel Cells, SOFCs, based power generation system. In the first step, a steady-state SOFCs system model was developed. The model includes the electrochemistry and the diffusion phenomena. The electrochemical model gives good agreement with experimental data in a wide operating range. Then, a parametric study has been conducted to estimate effects of the oxygen to carbon ratio, O/C, on reformer temperature, fuel cell temperature, fuel utilization, overall fuel cell performance, and the results are discussed in this paper. In the second step, a dynamic analysis of SOFCs characteristic has been developed. The aim of dynamic modelling was to find the response of the system against the fuel utilization and the O/C ratio variations. From the simulations, it was concluded that both developed models in the steady and dynamic state were reasonably accurate and can be used for system level optimization studies of the SOFC based power generation system.

IMPACTS OF INTERACTING ELEVATED ATMOSPHERIC CO2 AND O3 ON THE STRUCTURE AND FUNCTIONING OF A NORTHERN FOREST ECOSYSTEM: OPERATING AND DECOMMISSIONING THE ASPEN FACE PROJECT

Energy Technology Data Exchange (ETDEWEB)

Burton, Andrew J. [Michigan Technological University; Zak, Donald R. [University of Michigan; Kubiske, Mark E. [USDA Forest Service; Pregitzer, Kurt S. [University of Idaho

2014-06-30

Two of the most important and pervasive greenhouse gases driving global change and impacting forests in the U.S. and around the world are atmospheric CO2 and tropospheric O3. As the only free air, large-scale manipulative experiment studying the interaction of elevated CO2 and O3 on forests, the Aspen FACE experiment was uniquely designed to address the long-term ecosystem level impacts of these two greenhouse gases on aspen-birch-maple forests, which dominate the richly forested Lake States region. The project was established in 1997 to address the overarching scientific question: “What are the effects of elevated [CO2] and [O3], alone and in combination, on the structure and functioning of northern hardwood forest ecosystems?” From 1998 through the middle of the 2009 growing season, we examined the interacting effects of elevated CO2 and O3 on ecosystem processes in an aggrading northern forest ecosystem to compare the responses of early-successional, rapid-growing shade intolerant trembling aspen and paper birch to those of a late successional, slower growing shade tolerant sugar maple. Fumigations with elevated CO2 (560 ppm during daylight hours) and O3 (approximately 1.5 x ambient) were conducted during the growing season from 1998 to 2008, and in 2009 through harvest date. Response variables quantified during the experiment included growth, competitive interactions and stand dynamics, physiological processes, plant nutrient status and uptake, tissue biochemistry, litter quality and decomposition rates, hydrology, soil respiration, microbial community composition and respiration, VOC production, treatment-pest interactions, and treatment-phenology interactions. In 2009, we conducted a detailed harvest of the site. The harvest included detailed sampling of a subset of trees by component (leaves and buds, fine branches, coarse branches and stem, coarse roots, fine roots) and excavation of soil to a depth of 1 m. Throughout the experiment, aspen and birch

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.

Date palm waste gasification in downdraft gasifier and simulation using ASPEN HYSYS

International Nuclear Information System (INIS)

Bassyouni, M.; Waheed ul Hasan, Syed; Abdel-Aziz, M.H.; Abdel-hamid, S.M.-S.; Naveed, Shahid; Hussain, Ahmed; Ani, Farid Nasir

2014-01-01

Highlights: • Simulation of date palm waste gasification using ASPEN HYSYS was studied. • A steady state simulation of downdraft gasifier has been developed. • The results were used to predict synthesis gas composition. • Simulation results and experimental results are in good agreement. - Abstract: The present research aims to study the simulation of date palm waste gasification using ASPEN HYSYS. A steady state simulation of downdraft gasifier firing date palm leaves has been developed. The model is able to predict syngas composition with sound accuracy and can be used to find optimal operating conditions of the gasifier. Biomass is defined as an unconventional hypothetical solid component in HYSYS. A set of six reactor models simulates various reaction zones of the downdraft gasifier in accordance with its hydrodynamics. Biomass decomposition into constituents in the pyrolysis zone is modeled with a conversion reactor. The combustion of char and volatiles in the combustion zone are modeled with equilibrium and Gibbs reactor models respectively. The gasification zone is modeled with a Gibbs and equilibrium reactor. The results of simulation are validated against experimental results of a parametric variability study on a lab scale gasifier. The proportion of synthesis gas increase as temperature increases (concentration, molar fraction, and partial pressure). CO 2 and CH 4 in the product gases were also found to decrease with increasing temperature. At 800 °C, the exit gas reaches a stable molar composition (H 2 = 56.27%, CO = 21.71%, CO 2 = 18.24%, CH 4 = 3.78%). Increasing steam to biomass ratio increases CO 2 and H 2 at the expense of CO, governed by shift reaction. Steam induction increases the methane contents, thereby improves the heating value of the product gas

Date palm waste gasification in downdraft gasifier and simulation using ASPEN HYSYS

Energy Technology Data Exchange (ETDEWEB)

Bassyouni, M. [Department of Chemical and Materials Engineering, King Abdulaziz University, Rabigh 21911 (Saudi Arabia); Department of Chemical Engineering, Higher Technological Institute, Tenth of Ramdan City (Egypt); Waheed ul Hasan, Syed [Department of Chemical and Materials Engineering, King Abdulaziz University, Rabigh 21911 (Saudi Arabia); Abdel-Aziz, M.H., E-mail: helmy2002@gmail.com [Department of Chemical and Materials Engineering, King Abdulaziz University, Rabigh 21911 (Saudi Arabia); Chemical Engineering Department, Faculty of Engineering, Alexandria University, Alexandria (Egypt); Abdel-hamid, S. M.-S. [Department of Chemical Engineering, Higher Technological Institute, Tenth of Ramdan City (Egypt); Naveed, Shahid [Punjab Institute of Contemporary Sciences, 5.5 KM Raiwind Road, Lahore (Pakistan); Hussain, Ahmed [Department of Nuclear Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Ani, Farid Nasir [Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, UTM 81310 Johor Bahru (Malaysia)

2014-12-15

Highlights: • Simulation of date palm waste gasification using ASPEN HYSYS was studied. • A steady state simulation of downdraft gasifier has been developed. • The results were used to predict synthesis gas composition. • Simulation results and experimental results are in good agreement. - Abstract: The present research aims to study the simulation of date palm waste gasification using ASPEN HYSYS. A steady state simulation of downdraft gasifier firing date palm leaves has been developed. The model is able to predict syngas composition with sound accuracy and can be used to find optimal operating conditions of the gasifier. Biomass is defined as an unconventional hypothetical solid component in HYSYS. A set of six reactor models simulates various reaction zones of the downdraft gasifier in accordance with its hydrodynamics. Biomass decomposition into constituents in the pyrolysis zone is modeled with a conversion reactor. The combustion of char and volatiles in the combustion zone are modeled with equilibrium and Gibbs reactor models respectively. The gasification zone is modeled with a Gibbs and equilibrium reactor. The results of simulation are validated against experimental results of a parametric variability study on a lab scale gasifier. The proportion of synthesis gas increase as temperature increases (concentration, molar fraction, and partial pressure). CO{sub 2} and CH{sub 4} in the product gases were also found to decrease with increasing temperature. At 800 °C, the exit gas reaches a stable molar composition (H{sub 2} = 56.27%, CO = 21.71%, CO{sub 2} = 18.24%, CH{sub 4} = 3.78%). Increasing steam to biomass ratio increases CO{sub 2} and H{sub 2} at the expense of CO, governed by shift reaction. Steam induction increases the methane contents, thereby improves the heating value of the product gas.

Ecophysiology of Trembling Aspen in Response to Root-Zone Conditions and Competition on Reclaimed Mine Soil.

Science.gov (United States)

Bockstette, S.; Landhäusser, S.; Pinno, B.; Dyck, M. F.

2014-12-01

Reclaimed soils are typically characterized by increased bulk densities, penetration resistances and poor soil structure as well as associated problems with hydrology and aeration. As a result, available rooting space for planted tree seedlings is often restricted to a shallow layer of topsoil, which is usually of higher quality and is cultivated prior to planting. This may hinder the development of healthy root systems, thus drastically increasing the risk for plant stress by limiting access to soil resources such as water, nutrients and oxygen. These problems are exacerbated when herbaceous plants compete for the same resources within this limited root-zone. To understand how limited rooting space affects the physiology of young trees, we experimentally manipulated soil conditions and levels of competition at a reclaimed mine site in central Alberta, Canada. The site was characterized by heavily compacted, fine textured subsoil (~2.0 Mg ha-1), capped with 15 cm of topsoil (~1.5 Mg ha-1). In a replicated study (n=6) half the plots were treated with a subsoil plow to a depth of about 60 cm to increase available rooting spece. Subsequently, trembling aspen (Populus tremuloides Michx.) and smooth brome (Bromus inermis L.) were planted to create four vegetation covers: aspen (a), brome (b), aspen + brome (ab) and control (c) (no vegetation). Various soil properties, including texture, bulk density, penetration resistance and water availability, in conjunction with plant parameters such as root and shoot growth, leaf area development, sap flow, and stomatal conductance have since been monitored, both in-situ and through destructive sampling. Our results indicate that the soil treatment was effective in lowering bulk densities and penetration resistance, while improving moisture retention characteristics. Tree seedling growth and leaf area development were significantly greater without competition, but did not differ between soil treatments. The soil treatment generally

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

A comparative thermodynamic, economic and risk analysis concerning implementation of oxy-combustion power plants integrated with cryogenic and hybrid air separation units

International Nuclear Information System (INIS)

Skorek-Osikowska, Anna; Bartela, Łukasz; Kotowicz, Janusz

2015-01-01

Highlights: • Mathematical model of an integrated oxy-combustion power plant. • Comparison of a hybrid membrane–cryogenic oxygen generation plant with a cryogenic plant. • Thermodynamic analysis of the modeled cases of the plant. • Comparative economic analysis of the power plant with cryogenic and hybrid ASU. • Comparative risk analysis using a Monte Carlo method and sensitivity analysis. - Abstract: This paper presents a comparison of two types of oxy-combustion power plant that differ from each other in terms of the method of oxygen separation. For the purpose of the analysis, detailed thermodynamic models of oxy-fuel power plants with gross power of approximately 460 MW were built. In the first variant (Case 1), the plant is integrated with a cryogenic air separation unit (ASU). In the second variant (Case 2), the plant is integrated with a hybrid membrane–cryogenic installation. The models were built and optimized using the GateCycle, Aspen Plus and Aspen Custom Modeller software packages and with the use of our own computational codes. The results of the thermodynamic evaluation of the systems, which primarily uses indicators such as the auxiliary power and efficiencies of the whole system and of the individual components that constitute the unit, are presented. Better plant performance is observed for Case 2, which has a net efficiency of electricity generation that is 1.1 percentage points greater than that of Case 1. For the selected structure of the system, an economic analysis of the solutions was made. This analysis accounts for different scenarios of the functioning of the Emission Trading Scheme and includes detailed estimates of the investment costs in both cases. As an indicator of profitability, the break-even price of electricity was used primarily. The results of the analysis for the assumptions made are presented in this paper. A system with a hybrid air separation unit has slightly better economic performance. The break-even price

Techno-economic assessment of hybrid extraction and distillation processes for furfural production from lignocellulosic biomass.

Science.gov (United States)

Nhien, Le Cao; Long, Nguyen Van Duc; Kim, Sangyong; Lee, Moonyong

2017-01-01

Lignocellulosic biomass is one of the most promising alternatives for replacing mineral resources to overcome global warming, which has become the most important environmental issue in recent years. Furfural was listed by the National Renewable Energy Laboratory as one of the top 30 potential chemicals arising from biomass. However, the current production of furfural is energy intensive and uses inefficient technology. Thus, a hybrid purification process that combines extraction and distillation to produce furfural from lignocellulosic biomass was considered and investigated in detail to improve the process efficiency. This effective hybrid process depends on the extracting solvent, which was selected based on a comprehensive procedure that ranged from solvent screening to complete process design. Various solvents were first evaluated in terms of their extraction ability. Then, the most promising solvents were selected to study the separation feasibility. Eventually, processes that used the three best solvents (toluene, benzene, and butyl chloride) were designed and optimized in detail using Aspen Plus. Sustainability analysis was performed to evaluate these processes in terms of their energy requirements, total annual costs (TAC), and carbon dioxide (CO 2 ) emissions. The results showed that butyl chloride was the most suitable solvent for the hybrid furfural process because it could save 44.7% of the TAC while reducing the CO 2 emissions by 45.5% compared to the toluene process. In comparison with the traditional purification process using distillation, this suggested hybrid extraction/distillation process can save up to 19.2% of the TAC and reduce 58.3% total annual CO 2 emissions. Furthermore, a sensitivity analysis of the feed composition and its effect on the performance of the proposed hybrid system was conducted. Butyl chloride was found to be the most suitable solvent for the hybrid extraction/distillation process of furfural production. The proposed

How common is within-plant signalling via volatiles?

DEFF Research Database (Denmark)

Li, Tao; Blande, James D.

2017-01-01

or neighbouring plants to impending danger. It has been postulated that HIPVs evolved for within-plant signalling and that other organisms subsequently evolved to use them. However, only seven studies have reported HIPV-mediated within-plant signalling, most conducted in the laboratory or greenhouse. This leaves...... open the ecological relevance and evolutionary underpinning of the phenomenon. We recently observed within-plant signalling in hybrid aspen under laboratory and field conditions. Greenhouse experiments showed that HIPVs mediated the process. While our study adds an aspen hybrid to the list of plants...... in which within-plant signalling has been demonstrated, we lack understanding of how common the process is and whether plants obtain fitness benefits....

Effects of Tropospheric O3 on Trembling Aspen and Interaction with CO2: Results From An O3-Gradient and a Face Experiment

Science.gov (United States)

D.F. Karnosky; B. Mankovska; K. Percy; R.E. Dickson; G.K. Podila; J. Sober; A. Noormets; G. Hendrey; Mark D. Coleman; M. Kubiske; K.S. Pregitzer; J.G. Isebrands

1999-01-01

Abstract. Over the years, a series of trembling aspen (Populus tremuloides Michx.) clones differing in O3 sensitivity have been identified from OTC studies. Three clones (216 and 271[(O3 tolerant] and 259 [O3 sensitive]) have been characterized for O3...

Age-related patterns of forest complexity and carbon storage in pine and aspen-birch ecosystems of northern Minnesota, USA

International Nuclear Information System (INIS)

Bradford, J.B.; Kastendick, D.N.

2010-01-01

Forest managers are now developing strategies to mitigate increases in atmospheric carbon dioxide (CO 2 ) and help stands to adapt to new climatic conditions. This study characterized the influence of stand age on carbon storage and sequestration in chronosequences of even-aged red pine and aspen-birch stands in northern Minnesota. The aim of the study was to determine the impact of age-related management strategies on carbon storage and forest complexity. The pine chronosequences ranged from 7 to 160 years. Aspen chronosequences ranged from 6 to 133 years. Field measurements of the trees were compiled into 5 carbon pools. Carbon storage variables were averaged within each stand in order to conduct a regression analysis. The study showed that forest complexity was positively related to stand age in all of the measured response variables except species richness. Relationships between compositional complexity and stand age depended on forest type. Total carbon storage also increased with age. Results of the study showed that age plays an important role in overall ecosystem carbon storage. The study can be used to provide insights into the overall costs and benefits of forest management strategies that favour younger or older forests. 45 refs., 2 figs.

Information Literacy: Advancing Opportunities for Learning in the Digital Age. A Report of The Aspen Institute Forum on Communications and Society.

Science.gov (United States)

Adler, Richard P.; Breivik, Patricia Senn

This report is an informed observer's interpretation of the discussions that took place at the 1998 annual meeting of the Aspen Institute's Forum on Communications and Society (FOCAS). It summarizes the inquiry made by FOCAS members into the many issues surrounding information literacy, including what information literacy is, why we need an…

Fiber length and pulping characteristics of switchgrass, alfalfa stems, hybrid poplar and willow biomasses.

Science.gov (United States)

Ai, Jun; Tschirner, Ulrike

2010-01-01

Switchgrass (Panicum virgatum), alfalfa stems (Medicago sativa), second year growth hybrid poplar (Populus) and willow (Salix spp.) were examined to determine fiber characteristics, pulping behavior and paper properties. Alfalfa stems and switchgrass both showed length weighted average fiber length (LWW) of 0.78 mm, a very narrow fiber length distribution and high fines content. Willow and hybrid poplar have lower fines content but a very low average fiber length (0.42 and 0.48 mm LWW). In addition, the four biomass species showed distinctly different chemical compositions. Switchgrass was defibered successfully using Soda and Soda Anthraquinone (AQ) pulping and demonstrated good paper properties. Both fast-growing wood species pulped well using the Kraft process, and showed acceptable tensile strength, but low tear strength. Alfalfa stems reacted very poorly to Soda and Soda AQ pulping but responded well to Kraft and Kraft AQ. Pulps with tensile and tear strength considerably higher than those found for commercial aspen pulps were observed for alfalfa. All four biomass species examined demonstrated low pulp yield. The highest yields were obtained with poplar and switchgrass (around 43%). Considering the short fibers and low yields, all four biomass types will likely only be used in paper manufacturing if they offer considerable economic advantage over traditional pulp wood.

An in-depth assessment of hybrid solar–geothermal power generation

International Nuclear Information System (INIS)

Zhou, Cheng; Doroodchi, Elham; Moghtaderi, Behdad

2013-01-01

Highlights: • We model hybrid solar thermal and geothermal energy conversion system in the Australian context. • Solar thermal and geothermal energy can be effectively hybridised. • Thermodynamic advantages and economic benefits are realised. • Hybrid system overcomes adverse effects of diurnal temperature change on power generation. • Cost of electricity of an Enhanced Geothermal System can drop by more than 20% if hybridised with solar energy. - Abstract: A major problem faced by many standalone geothermal power plants, particularly in hot and arid climates such as Australia, is the adverse effects of diurnal temperature change on the operation of air-cooled condensers which typically leads to fluctuation in the power output and degradation of thermal efficiency. This study is concerned with the assessment of hybrid solar–geothermal power plants as a means of boosting the power output and where possible moderating the impact of diurnal temperature change. The ultimate goal is to explore the potential benefits from the synergies between the solar and geothermal energy sources. For this purpose the performances of the hybrid systems in terms of power output and the cost of electricity were compared with that of stand-alone solar and geothermal plants. Moreover, the influence of various controlling parameters including the ambient temperature, solar irradiance, geographical location, resource quality, and the operating mode of the power cycle on the performance of the hybrid system were investigated under steady-state conditions. Unsteady-state case studies were also performed to examine the dynamic behaviour of hybrid systems. These case studies were carried out for three different Australian geographic locations using raw hourly meteorological data of a typical year. The process simulation package Aspen-HYSYS was used to simulate plant configurations of interest. Thermodynamic analyses carried out for a reservoir temperature of 120 °C and a fixed

An in-depth assessment of hybrid solar–geothermal power generation

Energy Technology Data Exchange (ETDEWEB)

Zhou, Cheng [Priority Research Centre for Energy, Discipline of Chemical Engineering, School of Engineering, Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW 2308 (Australia); Doroodchi, Elham [Priority Research Centre for Advanced Particle Processing and Transport, Discipline of Chemical Engineering, School of Engineering, Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW 2308 (Australia); Moghtaderi, Behdad [Priority Research Centre for Energy, Discipline of Chemical Engineering, School of Engineering, Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW 2308 (Australia)

2013-10-15

Highlights: • We model hybrid solar thermal and geothermal energy conversion system in the Australian context. • Solar thermal and geothermal energy can be effectively hybridised. • Thermodynamic advantages and economic benefits are realised. • Hybrid system overcomes adverse effects of diurnal temperature change on power generation. • Cost of electricity of an Enhanced Geothermal System can drop by more than 20% if hybridised with solar energy. - Abstract: A major problem faced by many standalone geothermal power plants, particularly in hot and arid climates such as Australia, is the adverse effects of diurnal temperature change on the operation of air-cooled condensers which typically leads to fluctuation in the power output and degradation of thermal efficiency. This study is concerned with the assessment of hybrid solar–geothermal power plants as a means of boosting the power output and where possible moderating the impact of diurnal temperature change. The ultimate goal is to explore the potential benefits from the synergies between the solar and geothermal energy sources. For this purpose the performances of the hybrid systems in terms of power output and the cost of electricity were compared with that of stand-alone solar and geothermal plants. Moreover, the influence of various controlling parameters including the ambient temperature, solar irradiance, geographical location, resource quality, and the operating mode of the power cycle on the performance of the hybrid system were investigated under steady-state conditions. Unsteady-state case studies were also performed to examine the dynamic behaviour of hybrid systems. These case studies were carried out for three different Australian geographic locations using raw hourly meteorological data of a typical year. The process simulation package Aspen-HYSYS was used to simulate plant configurations of interest. Thermodynamic analyses carried out for a reservoir temperature of 120 °C and a fixed

Environmental benefits of cropland conversion to hybrid poplar: economic and policy considerations

International Nuclear Information System (INIS)

Updegraff, K.; Baughman, M.J.; Taff, S.J.

2004-01-01

To evaluate environmental benefits that might accrue from conversion of farmland to short-rotation woody crops (SRWC), a hypothetical conversion of 10%, 20% and 30% of cropland was modeled in a watershed of the Lower Minnesota River. The analysis synthesized output from a watershed model (ADAPT) with literature-based estimates of productivity and economic values for water quality, forest conservation and carbon sequestration. A Monte Carlo simulation approach was used to estimate ranges of environmental benefit values for cropland conversion to SRWCS. The summed average net benefits justified annual public subsidies ranging from $44 to 596 ha -1 , depending on market scenario and conversion level. Cropland conversion to SRWCs reduced cumulative annual stream flows, sediment and nitrogen loadings by up to 9%, 28% and 15%, respectively. Reduced sediment loads resulted in potential average annual public savings on culvert and ditch maintenance costs of $9.37 Mg -1 of sediment not delivered to the watershed outlet. Hybrid poplars over a 5-year rotation produced an estimated annual economic value due to carbon sequestration of $13-15 ha -1 when used for bioenergy and $29-33 ha -1 (depending on conversion rate) when converted to wood products. If hybrid poplars are substituted for aspen traditionally harvested from natural woodlands, the poplars create annual forest preservation values of $4.79-5.44 ha -1 . (author)

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

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...... with respect to a variety of SOFC inputs. SOFC stack operation on syn-gas is compared to operation on different coal properties and as expected there is a drop in performance, which is attributed to increased input fuel and air flow due to the lower quality of the fuel gas....

Full and part load exergetic analysis of a hybrid micro gas turbine fuel cell system based on existing components

International Nuclear Information System (INIS)

Bakalis, Diamantis P.; Stamatis, Anastassios G.

2012-01-01

Highlights: ► Hybrid SOFC/GT system based on existing components. ► Exergy analysis using AspenPlus™ software. ► Greenhouse gases emission is significantly affected by SOFC stack temperature. ► Comparison with a conventional GT of similar power. ► SOFC/GT is almost twice efficient in terms of second low efficiency and CO 2 emission. - Abstract: The paper deals with the examination of a hybrid system consisting of a pre-commercially available high temperature solid oxide fuel cell and an existing recuperated microturbine. The irreversibilities and thermodynamic inefficiencies of the system are evaluated after examining the full and partial load exergetic performance and estimating the amount of exergy destruction and the efficiency of each hybrid system component. At full load operation the system achieves an exergetic efficiency of 59.8%, which increases during the partial load operation, as a variable speed control method is utilized. Furthermore, the effects of the various performance parameters such as fuel cell stack temperature and fuel utilization factor are assessed. The results showed that the components in which chemical reactions occur have the higher exergy destruction rates. The exergetic performance of the system is affected significantly by the stack temperature. Based on the exergetic analysis, suggestions are given for reducing the overall system irreversibility. Finally, the environmental impact of the operation of the hybrid system is evaluated and compared with a similarly rated conventional gas turbine plant. From the comparison it is apparent that the hybrid system obtains nearly double exergetic efficiency and about half the amount of greenhouse gas emissions compared with the conventional plant.

The impact of vessel size on vulnerability curves: data and models for within-species variability in saplings of aspen, Populus tremuloides Michx.

Science.gov (United States)

Cai, Jing; Tyree, Melvin T

2010-07-01

The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel-size distributions. Measurements were done on seed-grown, 4-month-old aspen (Populus tremuloides Michx) grown in a greenhouse. VCs of stem segments were measured using a centrifuge technique and by a staining technique that allowed a VC to be constructed based on vessel diameter size-classes (D). Vessel-based VCs were also fitted to Weibull cumulative distribution functions (CDF), which provided best-fit values of Weibull CDF constants (c and b) and P(50) = the tension causing 50% loss of hydraulic conductivity. We show that P(50) = 6.166D(-0.3134) (R(2) = 0.995) and that b and 1/c are both linear functions of D with R(2) > 0.95. The results are discussed in terms of models of VCs based on vessel D size-classes and in terms of concepts such as the 'pit area hypothesis' and vessel pathway redundancy.

Multimodel simulations of forest harvesting effects on long‐term productivity and CN cycling in aspen forests.

Science.gov (United States)

Wang, Fugui; Mladenoff, David J; Forrester, Jodi A; Blanco, Juan A; Schelle, Robert M; Peckham, Scott D; Keough, Cindy; Lucash, Melissa S; Gower, Stith T

The effects of forest management on soil carbon (C) and nitrogen (N) dynamics vary by harvest type and species. We simulated long-term effects of bole-only harvesting of aspen (Populus tremuloides) on stand productivity and interaction of CN cycles with a multiple model approach. Five models, Biome-BGC, CENTURY, FORECAST, LANDIS-II with Century-based soil dynamics, and PnET-CN, were run for 350 yr with seven harvesting events on nutrient-poor, sandy soils representing northwestern Wisconsin, United States. Twenty CN state and flux variables were summarized from the models' outputs and statistically analyzed using ordination and variance analysis methods. The multiple models' averages suggest that bole-only harvest would not significantly affect long-term site productivity of aspen, though declines in soil organic matter and soil N were significant. Along with direct N removal by harvesting, extensive leaching after harvesting before canopy closure was another major cause of N depletion. These five models were notably different in output values of the 20 variables examined, although there were some similarities for certain variables. PnET-CN produced unique results for every variable, and CENTURY showed fewer outliers and similar temporal patterns to the mean of all models. In general, we demonstrated that when there are no site-specific data for fine-scale calibration and evaluation of a single model, the multiple model approach may be a more robust approach for long-term simulations. In addition, multimodeling may also improve the calibration and evaluation of an individual model.

Dual RBFNNs-Based Model-Free Adaptive Control With Aspen HYSYS Simulation.

Science.gov (United States)

Zhu, Yuanming; Hou, Zhongsheng; Qian, Feng; Du, Wenli

2017-03-01

In this brief, we propose a new data-driven model-free adaptive control (MFAC) method with dual radial basis function neural networks (RBFNNs) for a class of discrete-time nonlinear systems. The main novelty lies in that it provides a systematic design method for controller structure by the direct usage of I/O data, rather than using the first-principle model or offline identified plant model. The controller structure is determined by equivalent-dynamic-linearization representation of the ideal nonlinear controller, and the controller parameters are tuned by the pseudogradient information extracted from the I/O data of the plant, which can deal with the unknown nonlinear system. The stability of the closed-loop control system and the stability of the training process for RBFNNs are guaranteed by rigorous theoretical analysis. Meanwhile, the effectiveness and the applicability of the proposed method are further demonstrated by the numerical example and Aspen HYSYS simulation of distillation column in crude styrene produce process.

Utilization of steam- and explosion-decompressed aspen wood by some anaerobes. [Acetivibrio cellulolyticus, Clostridium saccharolyticum, Zymomonas anaerobia

Energy Technology Data Exchange (ETDEWEB)

Khan, A W; Asther, M; Giuliano, C

1984-01-01

Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes over 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also found to be suitable for the single-step conversion of cellulose to ethanol using cocultures consisting of cellylolytic and ethanol-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes. 16 references, 3 tables.

Dynamic Modeling and Plantwide Control of a Hybrid Power and Chemical Plant: An Integrated Gasification Combined Cycle Coupled with a Methanol Plant

Science.gov (United States)

Robinson, Patrick J.

simulators Aspen Plus and Aspen Dynamics. This dissertation first presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. Limitations in the software dealing with solids make this a necessary task. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudo fuel. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macro-scale thermal, flow, composition and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers, but merely presents an idea of how to dynamically simulate coal gasification in an approximate way. This dissertation also presents models of the downstream units of a typical IGCC. Dynamic simulations of the H2S absorption/stripping unit, Water-gas Shift (WGS) reactors, and CO2 absorption/stripping unit are essential for the development of stable and agile plantwide control structures of this hybrid power/chemical plant. Due to the high pressure of the system, hydrogen sulfide is removed by means of physical absorption. SELEXOLRTM (a mixture of the dimethyl ethers of polyethylene glycol) is used to achieve a gas purity of less than 5 ppm H2S. This desulfurized synthesis gas is sent to two water gas shift reactors that convert a total of 99% of carbon monoxide to hydrogen. Physical absorption of carbon dioxide with Selexol produces a hydrogen rich stream (90 mol% H2) to be fed into combustion turbines or to a methanol plant. Steady-state economic designs and plantwide control structures are developed in this dissertation. A steady-state economic design, control structure, and successful turndown of the methanol plant are shown in this dissertation. The Plantwide

Online community marketing of ski resorts : an in-depth best practice study of aspen/snowmass and breckenridge ski resort

OpenAIRE

Kráľ, Branislav

2013-01-01

Online brand community is a novel phenomenon that carries a number of benefits, but lack of clarity in antecedents of its effectiveness as a marketing alternative. Aspen/Snowmass and Breckenridge Ski Resort are two leading players in the ski industry, and this paper analyzes their activity in-depth in order to bring clarity by extracting implications on best practice. For the purpose, a tailor-made methodology is constructed. It consists of combining two analytical frameworks, interviews with...

Comparative analysis of the effect of pretreating aspen wood with aqueous and aqueous-organic solutions of sulfuric and nitric acid on its reactivity during enzymatic hydrolysis

DEFF Research Database (Denmark)

Dotsenko, Gleb; Osipov, D. O.; Zorov, I. N.

2016-01-01

The effect of aspen wood pretreatment methods with the use of both aqueous solutions of sulfuric and nitric acids and aqueous-organic solutions (ethanol, butanol) of sulfuric acid (organosolv) on the limiting degree of conversion of this type of raw material into simple sugars during enzymatic...

HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

Energy Technology Data Exchange (ETDEWEB)

Gorensek, M.

2011-07-06

Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.

Modelling and testing the performance of a commercial ammonia/water absorption chiller using Aspen-Plus platform

International Nuclear Information System (INIS)

Mansouri, Rami; Boukholda, Ismail; Bourouis, Mahmoud; Bellagi, Ahmed

2015-01-01

A steady-state simulation model of a commercial 3-ton ammonia/water absorption chiller is developed and validated using the flow-sheeting software Aspen-Plus. First an appropriate thermodynamic property model for the ammonia/water fluid mixture is selected. To this purpose nine methods from the software library are pre-selected and tested, but none of the methods predicts the VLE (vapour–liquid equilibrium) with sufficient accuracy. The interaction parameters of these models are then determined by fitting the equations of state (EOS) to VLE data. It is finally found that the Boston–Mathias modified Peng–Robinson EOS with fitted parameters predicts most accurately the VLE for the temperature and pressure ranges encountered in commercial chillers. A simulation model of the machine is then developed. The simulation results are found to be in good agreement with data from literature at a cooling air temperature of 35 ºC. The heat transfer characteristics (UA) of the various heat exchangers of the machine are then determined and the model modified to make it accept these (UA) as input parameters. The comparison of the simulation predictions at cooling air temperatures of 26.7 and 38 ºC with the bibliographical data showed good concordance. The proposed model could be very useful for the analysis and performance prediction of the commercial absorption chiller. - Highlights: • A commercial NH 3 /H 2 O absorption chiller is simulated using the software Aspen-Plus. • Peng-Robinson-Boston-Mathias equation of state is used to predict VLE of NH 3 /H 2 O fluid mixture. • A steady-state model describing the chiller operation is developed. • The model predicts the internal operating conditions and COP of the chiller.

Genetic analysis of post-mating reproductive barriers in hybridizing European Populus species.

Science.gov (United States)

Macaya-Sanz, D; Suter, L; Joseph, J; Barbará, T; Alba, N; González-Martínez, S C; Widmer, A; Lexer, C

2011-10-01

Molecular genetic analyses of experimental crosses provide important information on the strength and nature of post-mating barriers to gene exchange between divergent populations, which are topics of great interest to evolutionary geneticists and breeders. Although not a trivial task in long-lived organisms such as trees, experimental interspecific recombinants can sometimes be created through controlled crosses involving natural F(1)'s. Here, we used this approach to understand the genetics of post-mating isolation and barriers to introgression in Populus alba and Populus tremula, two ecologically divergent, hybridizing forest trees. We studied 86 interspecific backcross (BC(1)) progeny and >350 individuals from natural populations of these species for up to 98 nuclear genetic markers, including microsatellites, indels and single nucleotide polymorphisms, and inferred the origin of the cytoplasm of the cross with plastid DNA. Genetic analysis of the BC(1) revealed extensive segregation distortions on six chromosomes, and >90% of these (12 out of 13) favored P. tremula donor alleles in the heterospecific genomic background. Since selection was documented during early diploid stages of the progeny, this surprising result was attributed to epistasis, cyto-nuclear coadaptation, heterozygote advantage at nuclear loci experiencing introgression or a combination of these. Our results indicate that gene flow across 'porous' species barriers affects these poplars and aspens beyond neutral, Mendelian expectations and suggests the mechanisms responsible. Contrary to expectations, the Populus sex determination region is not protected from introgression. Understanding the population dynamics of the Populus sex determination region will require tests based on natural interspecific hybrid zones.

A hybrid solar chemical looping combustion system with a high solar share

International Nuclear Information System (INIS)

Jafarian, Mehdi; Arjomandi, Maziar; Nathan, Graham J.

2014-01-01

Highlights: • A novel hybrid solar chemical looping combustion system is presented. • This hybrid CLC system integrates a CLC plant with a solar thermal energy plant. • The oxygen carrier particles are used for chemical and sensible thermal energy storage. • A solar cavity reactor is proposed for fuel reactor. • The calculations show a total solar share of around 60% can be achieved. - Abstract: A novel hybrid solar chemical looping combustion (Hy-Sol-CLC) is presented, in which the oxygen carrier particles in a CLC system are employed to provide thermal energy storage for concentrated solar thermal energy. This hybrid aims to take advantage of key features of a chemical looping combustion (CLC) system that are desirable for solar energy systems, notably their inherent chemical and sensible energy storage systems, the relatively low temperature of the “fuel” reactor (to which the concentrated solar thermal energy is added in a hybrid) relative to that of the final temperature of the product gas and the potential to operate the fuel reactor at a different pressure to the heated gas stream. By this approach, it is aimed to achieve high efficiency of the solar energy, infrastructure sharing, economic synergy, base load power generation and a high solar fraction of the total energy. In the proposed Hy-Sol-CLC system, a cavity solar receiver has been chosen for fuel reactor while for the storage of the oxygen carrier particles two reservoirs have been added to a conventional CLC. A heat exchanger is also proposed to provide independent control of the temperatures of the storage reservoirs from those of solar fuel and air reactors. The system is simulated using Aspen Plus software for the average diurnal profile of normal irradiance for Port Augusta, South Australia. The operating temperature of the fuel reactor, solar absorption efficiency, solar share, fraction of the solar thermal energy stored within the solar reactor, the fractions of sensible and

Different growth strategies determine the carbon gain and productivity of aspen collectives to be used in short-rotation plantations

International Nuclear Information System (INIS)

Müller, Annika; Horna, Viviana; Zhang, Chunxia; Leuschner, Christoph

2012-01-01

Populus tremula is a favoured tree species in short-rotation forestry with a recognised large intraspecific variation in productivity. We compared the growth potential of 1-yr-old saplings of four Central European aspen collectives with different climate adaptation on a low-fertility site and searched for growth-determining physiological and morphological traits and their dependence on genetic constitution. Among the 35 investigated traits were photosynthetic capacity and mean assimilation rate, quantum yield and carboxylation efficiency, leaf water potential, leaf phaenology and the ratio of leaves lost to leaves produced (LP ratio), leaf size and total leaf area, axes length growth and canopy carbon gain as an estimate of productivity. The collectives differed by more than 30% in cumulative carbon gain with a large genotype effect, while mean assimilation rate and most photosynthetic and water status traits showed a relatively small intraspecific variation with no significant influence on the variation in C gain. The timing of the beginning of net leaf loss (leaf abscission > leaf production) in August differed between the four collectives and resulted in different maximum leaf areas and LP ratios, which were identified as key factors controlling C gain. Mean assimilation rate, though not related to cumulative C gain, was positively correlated with the light, CO 2 and water use efficiencies of photosynthesis. We conclude that genotype selection for high-yielding aspen in short-rotation forestry at low-fertility sites should focus on the parameters leaf phaenology, LP ratio at the end of the growing season, and the resulting total leaf area as key traits.

Aspen Plus® and economic modeling of equine waste utilization for localized hot water heating via fast pyrolysis.

Science.gov (United States)

Hammer, Nicole L; Boateng, Akwasi A; Mullen, Charles A; Wheeler, M Clayton

2013-10-15

Aspen Plus(®) based simulation models have been developed to design a pyrolysis process for 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 the available waste from the site's 41 horses requires a 6 oven dry metric ton per day (ODMTPD) pyrolysis system but it will require a 15 ODMTPD system for waste generated by an additional 150 horses at the expanded area including the College and its vicinity. For this a dual fluidized bed combustion reduction integrated pyrolysis system (CRIPS) developed at USDA's Agricultural Research Service (ARS) was identified as the technology of choice for pyrolysis oil production. The Aspen Plus(®) model was further used to consider the combustion of the produced pyrolysis oil (bio-oil) in the existing boilers that generate hot water for space heating at the Equine Center. The model results show the potential for both the equine facility and the College to displace diesel fuel (fossil) with renewable pyrolysis oil and alleviate a costly waste disposal problem. We predict that all the heat required to operate the pyrolyzer could be supplied by non-condensable gas and about 40% of the biochar co-produced with bio-oil. Techno-economic Analysis shows neither design is economical at current market conditions; however the 15 ODMTPD CRIPS design would break even when diesel prices reach $11.40/gal. This can be further improved to $7.50/gal if the design capacity is maintained at 6 ODMTPD but operated at 4950 h per annum. Published by Elsevier Ltd.

How common is within-plant signaling via volatiles?

Science.gov (United States)

Li, Tao; Blande, James D

2017-08-03

Many plants respond to herbivory by releasing a complex blend of volatiles that may differ from that emitted by intact counterparts. These herbivore-induced plant volatiles (HIPV) mediate many interactions among plants and their community members, including alerting undamaged leaves of the attacked or neighboring plants to impending danger. It has been postulated that HIPVs evolved for within-plant signaling and that other organisms subsequently evolved to use them. However, only 7 studies have reported HIPV-mediated within-plant signaling, most conducted in the laboratory or greenhouse. This leaves open the ecological relevance and evolutionary underpinning of the phenomenon. We recently observed within-plant signaling in hybrid aspen under laboratory and field conditions. Greenhouse experiments showed that HIPVs mediated the process. While our study adds an aspen hybrid to the list of plants in which within-plant signaling has been demonstrated, we lack understanding of how common the process is and whether plants obtain fitness benefits.

Elevated CO2 response of photosynthesis depends on ozone concentration in aspen

International Nuclear Information System (INIS)

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

2010-01-01

The effect of elevated CO 2 and O 3 on apparent quantum yield (φ), maximum photosynthesis (P max ), carboxylation efficiency (V cmax ) and electron transport capacity (J max ) at different canopy locations was studied in two aspen (Populus tremuloides) clones of contrasting O 3 tolerance. Local light climate at every leaf was characterized as fraction of above-canopy photosynthetic photon flux density (%PPFD). Elevated CO 2 alone did not affect φ or P max , and increased J max in the O 3 -sensitive, but not in the O 3 -tolerant clone. Elevated O 3 decreased leaf chlorophyll content and all photosynthetic parameters, particularly in the lower canopy, and the negative impact of O 3 increased through time. Significant interaction effect, whereby the negative impact of elevated O 3 was exaggerated by elevated CO 2 was seen in Chl, N and J max , and occurred in both O 3 -tolerant and O 3 -sensitive clones. The clonal differences in the level of CO 2 x O 3 interaction suggest a relationship between photosynthetic acclimation and background O 3 concentration. - Photosynthetic acclimation to elevated CO 2 depends on the background oxidant levels.

Simulation of the gasification of animal wastes in a dual gasifier using Aspen Plus®

International Nuclear Information System (INIS)

Fernandez-Lopez, M.; Pedroche, J.; Valverde, J.L.; Sanchez-Silva, L.

2017-01-01

Highlights: • The gasification of manure was evaluated using the software Aspen Plus®. • Composition and LHV of the obtained syngas depends on the operating conditions. • CO 2 net emissions for the steam and CO 2 gasification processes were calculated. • Manure steam gasification can be used as feedstock for Fischer-Tropsch. • Manure CO 2 gasification lead to a syngas suitable for energy production. - Abstract: The gasification of an animal waste biomass (manure) in a dual gasifier was studied using the software Aspen Plus®. For this purpose, a model based on a Gibbs free energy reactor was considered. Effects of the gasification temperature, the gasifying/biomass ratio and the use of steam and CO 2 as the gasifying agents on the composition and the low heating value (LHV) of the produced syngas were evaluated. In this sense, the H 2 /CO ratio and the LHV were the parameters calculated to stablish the best operating conditions for the production of either hydrocarbons via Fischer-Tropsch or energy. Furthermore, the CO 2 net emissions generated by the gasification process were also important in the selection of the best operating conditions from an environmental point of view. The obtained results showed that for both gasifying agents the H 2 and CO production was favoured at high temperatures whereas the production of CH 4 and CO 2 was favoured at low ones. On the other hand, the H 2 production was higher when steam was used as the gasifying agent and the formation of CO was enhanced when CO 2 was considered as gasification agent. An increase of the gasifying agent/biomass ratio had a negatively influence on the production of CH 4 , leading to a decrease of the LHV. Therefore, steam as the gasifying agent and high temperatures favoured the obtaining of a syngas suitable for the Fischer-Tropsch process whereas CO 2 and low gasification temperatures enhanced a syngas with a high LHV which could be used for energy production. Finally, the net CO 2

Simulation and statistical analysis for the optimization of nitrogen liquefaction plant with cryogenic Claude cycle using process modeling tool: ASPEN HYSYS

International Nuclear Information System (INIS)

Joshi, D.M.

2017-01-01

Cryogenic technology is used for liquefaction of many gases and it has several applications in food process engineering. Temperatures below 123 K are considered to be in the field of cryogenics. Extreme low temperatures are a basic need for many industrial processes and have several applications, such as superconductivity of magnets, space, medicine and gas industries. Several methods can be used to obtain the low temperatures required for liquefaction of gases. 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, is the basic liquefaction process. Different cryogenic cycle configurations are designed for getting the liquefied form of gases at different temperatures. Each of the cryogenic cycles like Linde cycle, Claude cycle, Kapitza cycle or modified Claude cycle has its own advantages and disadvantages. The placement of heat exchangers, Joule-Thompson valve and turboexpander decides the configuration of a cryogenic cycle. Each configuration has its own efficiency according to the application. Here, a nitrogen liquefaction plant is used for the analysis purpose. The process modeling tool ASPEN HYSYS can provide a software simulation approach before the actual implementation of the plant in the field. This paper presents the simulation and statistical analysis of the Claude cycle with the process modeling tool ASPEN HYSYS. It covers the technique used to optimize the liquefaction of the plant. The simulation results so obtained can be used as a reference for the design and optimization of the nitrogen liquefaction plant. Efficient liquefaction will give the best performance and productivity to the plant.

Simulation and statistical analysis for the optimization of nitrogen liquefaction plant with cryogenic Claude cycle using process modeling tool: ASPEN HYSYS

Science.gov (United States)

Joshi, D. M.

2017-09-01

Cryogenic technology is used for liquefaction of many gases and it has several applications in food process engineering. Temperatures below 123 K are considered to be in the field of cryogenics. Extreme low temperatures are a basic need for many industrial processes and have several applications, such as superconductivity of magnets, space, medicine and gas industries. Several methods can be used to obtain the low temperatures required for liquefaction of gases. 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, is the basic liquefaction process. Different cryogenic cycle configurations are designed for getting the liquefied form of gases at different temperatures. Each of the cryogenic cycles like Linde cycle, Claude cycle, Kapitza cycle or modified Claude cycle has its own advantages and disadvantages. The placement of heat exchangers, Joule-Thompson valve and turboexpander decides the configuration of a cryogenic cycle. Each configuration has its own efficiency according to the application. Here, a nitrogen liquefaction plant is used for the analysis purpose. The process modeling tool ASPEN HYSYS can provide a software simulation approach before the actual implementation of the plant in the field. This paper presents the simulation and statistical analysis of the Claude cycle with the process modeling tool ASPEN HYSYS. It covers the technique used to optimize the liquefaction of the plant. The simulation results so obtained can be used as a reference for the design and optimization of the nitrogen liquefaction plant. Efficient liquefaction will give the best performance and productivity to the plant.

Initial soil respiration response to biomass harvesting and green-tree retention in aspen-dominated forests of the Great Lakes region

Science.gov (United States)

Kurth, Valerie J.; Bradford, John B.; Slesak, Robert A.; D'Amato, Anthony W.

2014-01-01

Contemporary forest management practices are increasingly designed to optimize novel objectives, such as maximizing biomass feedstocks and/or maintaining ecological legacies, but many uncertainties exist regarding how these practices influence forest carbon (C) cycling. We examined the responses of soil respiration (Rs) to biomass harvesting and green-tree retention in an effort to empirically assess their impacts on C cycling. We measured Rs and soil microclimatic variables over four growing seasons following implementation of these management practices using a fully replicated, operational-scale experiment in aspen-dominated forests in northern Minnesota. Treatments included three levels of biomass removal within harvested areas: whole-tree harvest (no slash deliberately retained), 20% slash retained, and stem-only harvest (all slash retained), and two levels of green-tree retention: 0.1 ha aggregate or none. The relative amount of biomass removed had a negligible effect on Rs in harvested areas, but treatment effects were probably obscured by heterogeneous slash configurations and rapid post-harvest regeneration of aspen in all of the treatments. Discrete measurements of Rs and soil temperature within green-tree aggregates were not discernible from surrounding harvested areas or unharvested control stands until the fourth year following harvest, when Rs was higher in unharvested controls than in aggregates and harvested stands. Growing season estimates of Rs showed that unharvested control stands had higher Rs than both harvested stands and aggregates in the first and third years following harvest. Our results suggest that retention of larger forest aggregates may be necessary to maintain ecosystem-level responses similar to those in unharvested stands. Moreover, they highlight the innate complexity of operational-scale research and suggest that the initial impacts of biomass harvest on Rs may be indiscernible from traditional harvest in systems where incidental

Hybrid mimics and hybrid vigor in Arabidopsis

Science.gov (United States)

Wang, Li; Greaves, Ian K.; Groszmann, Michael; Wu, Li Min; Dennis, Elizabeth S.; Peacock, W. James

2015-01-01

F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics of the F1 hybrid are stabilized. These hybrid mimic lines, like the F1 hybrid, have larger leaves than the parent plant, and the leaves have increased photosynthetic cell numbers, and in some lines, increased size of cells, suggesting an increased supply of photosynthate. A comparison of the differentially expressed genes in the F1 hybrid with those of eight hybrid mimic lines identified metabolic pathways altered in both; these pathways include down-regulation of defense response pathways and altered abiotic response pathways. F6 hybrid mimic lines are mostly homozygous at each locus in the genome and yet retain the large F1-like phenotype. Many alleles in the F6 plants, when they are homozygous, have expression levels different to the level in the parent. We consider this altered expression to be a consequence of transregulation of genes from one parent by genes from the other parent. Transregulation could also arise from epigenetic modifications in the F1. The pure breeding hybrid mimics have been valuable in probing the mechanisms of hybrid vigor and may also prove to be useful hybrid vigor equivalents in agriculture. PMID:26283378

In vivo production of non-glycosylated recombinant proteins in Nicotiana benthamiana plants by co-expression with Endo-β-N-acetylglucosaminidase H (Endo H) of Streptomyces plicatus

Science.gov (United States)

Cicek, Kader; Gulec, Burcu; Ungor, Rifat; Hasanova, Gulnara

2017-01-01

A plant transient expression system, with eukaryotic post-translational modification machinery, offers superior efficiency, scalability, safety, and lower cost over other expression systems. However, due to aberrant N-glycosylation, this expression system may not be a suitable expression platform for proteins not carrying N-linked glycans in the native hosts. Therefore, it is crucial to develop a strategy to produce target proteins in a non-glycosylated form while preserving their native sequence, conformation and biological activity. Previously, we developed a strategy for enzymatic deglycosylation of proteins in planta by co-expressing bacterial peptide-N-glycosidase F (PNGase F). Though PNGase F removes oligosaccharides from glycosylated proteins, in so doing it causes an amino acid change due to the deamidation of asparagine to aspartate in the N-X-S/T site. Endo-β-N-acetylglucosaminidase (EC3.2.1.96, Endo H), another deglycosylating enzyme, catalyzes cleavage between two N-Acetyl-D-glucosamine residues of the chitobiose core of N-linked glycans, leaving a single N-Acetyl-D-glucosamine residue without the concomitant deamidation of asparagine. In this study, a method for in vivo deglycosylation of recombinant proteins in plants by transient co-expression with bacterial Endo H is described for the first time. Endo H was fully active in vivo. and successfully cleaved N-linked glycans from glycoproteins were tested. In addition, unlike the glycosylated form, in vivo Endo H deglycosylated Pfs48/45 was recognized by conformational specific Pfs48/45 monoclonal antibody, in a manner similar to its PNGase F deglycosylated counterpart. Furthermore, the deglycosylated PA83 molecule produced by Endo H showed better stability than a PNGase F deglycosylated counterpart. Thus, an Endo H in vivo deglycosylation approach provides another opportunity to develop vaccine antigens, therapeutic proteins, antibodies, and industrial enzymes. PMID:28827815

Lignin and related compounds. VIII. Lignin monomers and dimers from hydrogenolysis of aspen wood using rhodium-on-charcoal catalyst

Energy Technology Data Exchange (ETDEWEB)

Sudo, K; Mullord, D J; Pepper, J M

1981-04-01

Aspen poplar wood meal has been subjected to catalytic hydrogenolysis in dioxane-water (9:1) at 500 psig initial pressure of hydrogen over a 5% rhodium-on-charcoal catalyst for five hours at 195 plus or minus 5 degrees C. The resulting chloroform-soluble lignin degradation products were separated by cellulose and silica gel column chromatography. The following compounds were isolated and identified: 4-hydroxybenzoic acid, 1-(4-hydroxy-3,4-dimethoxyphenyl)-1-propanone (propiosyringone), 2,2'-dihydroxy-3,3'-dimethoxy- 5,5'-dipropylbiphenyl, 2,3-bis(4-hydroxy-3,5- dimethoxyphenyl)-1-propanol, and a mixture of 3-(4-hydroxy-3,5-dimethoxyphenyl)-2(4-hydroxy- 3-methoxyphenyl)-1-propan and 3-(4-hydroxy-3- methoxyphenyl)-2-(4-hydroxy-3,5-dimethoxyphenyl)-1- propanol. 9 references.

The energetic performance of a novel hybrid solar thermal and chemical looping combustion plant

International Nuclear Information System (INIS)

Jafarian, Mehdi; Arjomandi, Maziar; Nathan, Graham J.

2014-01-01

Highlights: • A hybrid solar chemical looping combustion power cycle is reported. • The cycle is studied for two configurations, with and without an after-burner. • The oxygen carrier particles are used as storage medium for solar thermal energy. • Total solar shares of 41.4% and 60% are achieved with and without the after-burner. • Efficiencies of 50% and 44.0% are achieved with and without the after-burner. - Abstract: The overall energetic performance of a gas turbine combined cycle powered by a hybrid cycle between a solar thermal and a chemical looping combustion (CLC) system firing methane is reported for two configurations. In one case, the outlet from the air reactor is fed directly to a gas turbine, while in the other an after-burner, also firing methane, is added to increase the gas turbine inlet temperature. The cycle is simulated using Aspen Plus software for the average diurnal profile of normal irradiance for Port Augusta, South Australia. The first law efficiency, total solar absorption efficiency, average and peak fractional power boosts, total solar share, net solar to electrical efficiency, fraction of pressurised CO 2 , incremental CO 2 avoidance and the exergy efficiency for both cycles are reported. The calculations predict a first law efficiency of 50.0% for the cycle employing an after-burner, compared with 44.0% for that without the after-burner. However, this is achieved at the cost of decreasing the solar share from 60.0%, without the after-burner, to 41.4% with it. Also reported is the sensitivity analysis of performance to variations in key operating parameters. The sensitivity analysis shows that further improvements to the performance of the cycle are possible

Studies on the products resulting from the conversion of aspen poplar to an oil

Energy Technology Data Exchange (ETDEWEB)

Eager, R L; Mathews, J F; Pepper, J M; Zohdi, H

1981-01-01

The reactions involved in the conversion of aspen poplar into a variety of chemical products as a result of its interaction with CO and H/sub 2/O in the presence of Na/sub 2/CO/sub 3/ at elevated temperatures and pressures are considered. The original C content of the wood is distributed between an oil phase, a complex mixture of highly oxygenated H/sub 2/O-soluble products many of which were identified as low-molecular-weight aliphatic alcohols, ketones, and acids, and a gaseous phase consisting of mainly H and CO/sub 2/. Using model substances (cellulose, cellobiose, -D-glucose, D-fructose, D-xylose, sorbitol, glycerol, and an isolated lignin) information was obtained on the origin of the oil and of the H/sub 2/O-soluble products. Studies at 160 degrees - 360 degrees revealed a marked exothermic reaction occurring at 200-240 degrees for wood and cellulose, which was reflected in the nature of the resulting product. With increasing temperature an increase in the yields of the H/sub 2/O-souluble derivatives and also a change in their relative abundance was observed.

A novel strategy for global mapping of O-GlcNAc proteins and peptides using selective enzymatic deglycosylation, HILIC enrichment and mass spectrometry identification.

Science.gov (United States)

Shen, Bingquan; Zhang, Wanjun; Shi, Zhaomei; Tian, Fang; Deng, Yulin; Sun, Changqing; Wang, Guangshun; Qin, Weijie; Qian, Xiaohong

2017-07-01

O-GlcNAcylation is a kind of dynamic O-linked glycosylation of nucleocytoplasmic and mitochondrial proteins. It serves as a major nutrient sensor to regulate numerous biological processes including transcriptional regulation, cell metabolism, cellular signaling, and protein degradation. Dysregulation of cellular O-GlcNAcylated levels contributes to the etiologies of many diseases such as diabetes, neurodegenerative disease and cancer. However, deeper insight into the biological mechanism of O-GlcNAcylation is hampered by its extremely low stoichiometry and the lack of efficient enrichment approaches for large-scale identification by mass spectrometry. Herein, we developed a novel strategy for the global identification of O-GlcNAc proteins and peptides using selective enzymatic deglycosylation, HILIC enrichment and mass spectrometry analysis. Standard O-GlcNAc peptides can be efficiently enriched even in the presence of 500-fold more abundant non-O-GlcNAc peptides and identified by mass spectrometry with a low nanogram detection sensitivity. This strategy successfully achieved the first large-scale enrichment and characterization of O-GlcNAc proteins and peptides in human urine. A total of 474 O-GlcNAc peptides corresponding to 457 O-GlcNAc proteins were identified by mass spectrometry analysis, which is at least three times more than that obtained by commonly used enrichment methods. A large number of unreported O-GlcNAc proteins related to cell cycle, biological regulation, metabolic and developmental process were found in our data. The above results demonstrated that this novel strategy is highly efficient in the global enrichment and identification of O-GlcNAc peptides. These data provide new insights into the biological function of O-GlcNAcylation in human urine, which is correlated with the physiological states and pathological changes of human body and therefore indicate the potential of this strategy for biomarker discovery from human urine. Copyright �

Hybrid Propulsion Demonstration Program 250K Hybrid Motor

Science.gov (United States)

Story, George; Zoladz, Tom; Arves, Joe; Kearney, Darren; Abel, Terry; Park, O.

2003-01-01

The Hybrid Propulsion Demonstration Program (HPDP) program was formed to mature hybrid propulsion technology to a readiness level sufficient to enable commercialization for various space launch applications. The goal of the HPDP was to develop and test a 250,000 pound vacuum thrust hybrid booster in order to demonstrate hybrid propulsion technology and enable manufacturing of large hybrid boosters for current and future space launch vehicles. The HPDP has successfully conducted four tests of the 250,000 pound thrust hybrid rocket motor at NASA's Stennis Space Center. This paper documents the test series.

Model estimates of leaf area and reference canopy stomatal conductance suggest correlation between phenology and physiology in both trembling aspen and red pine

Science.gov (United States)

Mackay, D. S.; Ewers, B. E.; Kruger, E. L.

2006-12-01

Phenological variations impact water and carbon fluxes, as evidenced by the large interannual variability of net ecosystem exchange of carbon dioxide and evapotranspiration (ET). In northern Wisconsin we observed daily variations of canopy transpiration from hardwoods from 1.0 to 1.7 mm/day during the leaf unfolding period and 1.7 to 2.6 mm/day with leaves fully out. Correlations between such flux rates and phenology have not been extensively tested and mechanistic connections are in their infancy. Some data suggest that stomatal conductance and photosynthesis increases up to full expansion. Moreover, in conifers, the interaction of phenology and physiology is more complicated than in deciduous trees because needles are retained for several years. Using inverse modeling with a coupled photosynthesis-transpiration model we estimated reference canopy stomatal conductance, Gsref, for red pine (Pinus resinosa), and Gsref and leaf area index, L, for trembling aspen (Populus tremuloides), using 30-min continuous sap flux data spanning a period from just prior to the start of leaf expansion to just after leaf senescence. The red pine showed Gsref ramp up from 105 to 179 mmol m-2 leaf s-1, which represented a 37 to 50 percent increase in Gsref after accounting for maximum possible changes in L. After full leaf out, the trembling aspen were almost immediately defoliated, and then reflushed after three weeks. Model estimates of L reflected this pattern and were consistent with measurements. However, Gsref never exceeded 45 mmol m-2 s-1 prior to defoliation, but peaked at 112 mmol m-2 s-1 after reflushing. These results support the need for further work that aims to separate phenology and physiology.

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

oligosaccharide unit per molecule. Here, the deglycosylated form of the enzyme was obtained by periodate oxidation. The differences in the glycosylated and deglycosylated forms of the glycoprotein have been studied at various temperatures and pH values, ...

Development of once-through hybrid sulfur process for nuclear hydrogen production

International Nuclear Information System (INIS)

Jung, Yong Hun

2010-02-01

Humanity has been facing major energy challenges such as the severe climate change, threat of energy security and global energy shortage especially for the developing world. Particularly, growing awareness of the global warming has led to efforts to develop the sustainable energy technologies for the harmony of the economy, social welfare and environment. Water-splitting nuclear hydrogen production is expected to help to resolve those challenges, when high energy efficiency and low cost for hydrogen production become possible. Once-through Hybrid Sulfur process (Ot-HyS), proposed in this work, produces hydrogen using the same SO 2 Depolarized water Electrolysis (SDE) process found in the original Hybrid Sulfur cycle (HyS) proposed by Westinghouse, which has the sulfuric acid decomposition (SAD) process using high temperature heat source in order to recover sulfur dioxide for the SDE process. But Ot-HyS eliminated this technical hurdle by replacing it with well-established sulfur combustion process to feed sulfur dioxide to the SDE process. Because Ot-HyS has less technical challenges, Ot-HyS is expected to advance the realization of the large-scale nuclear hydrogen production by feeding an initial nuclear hydrogen stock. Most of the elemental sulfur, at present, is supplied by desulfurization process for environmental reasons during the processing of natural gas and petroleum refining and expected to increase significantly. This recovered sulfur will be burned with oxygen in the sulfur combustion process so that produced sulfur dioxide could be supplied to the SDE process to produce hydrogen. Because the sulfur combustion is a highly exothermic reaction releasing 297 kJ/mol of combustion heat resulting in a large temperature rise, efficiency of the Ot-HyS is expected to be high by recovering this great amount of high grade excess heat with nuclear energy. Sulfuric acid, which is a byproduct of the SDE process, could be sent to the neighboring consumers with or even

ASPEN: A fully kinetic, reduced-description particle-in-cell model for simulating parametric instabilities

International Nuclear Information System (INIS)

Vu, H.X.; Bezzerides, B.; DuBois, D.F.

1999-01-01

A fully kinetic, reduced-description particle-in-cell (RPIC) model is presented in which deviations from quasineutrality, electron and ion kinetic effects, and nonlinear interactions between low-frequency and high-frequency parametric instabilities are modeled correctly. The model is based on a reduced description where the electromagnetic field is represented by three separate temporal envelopes in order to model parametric instabilities with low-frequency and high-frequency daughter waves. Because temporal envelope approximations are invoked, the simulation can be performed on the electron time scale instead of the time scale of the light waves. The electrons and ions are represented by discrete finite-size particles, permitting electron and ion kinetic effects to be modeled properly. The Poisson equation is utilized to ensure that space-charge effects are included. The RPIC model is fully three dimensional and has been implemented in two dimensions on the Accelerated Strategic Computing Initiative (ASCI) parallel computer at Los Alamos National Laboratory, and the resulting simulation code has been named ASPEN. The authors believe this code is the first particle-in-cell code capable of simulating the interaction between low-frequency and high-frequency parametric instabilities in multiple dimensions. Test simulations of stimulated Raman scattering, stimulated Brillouin scattering, and Langmuir decay instability are presented

Thermochemical Equilibrium Model of Synthetic Natural Gas Production from Coal Gasification Using Aspen Plus

Directory of Open Access Journals (Sweden)

Rolando Barrera

2014-01-01

Full Text Available The production of synthetic or substitute natural gas (SNG from coal is a process of interest in Colombia where the reserves-to-production ratio (R/P for natural gas is expected to be between 7 and 10 years, while the R/P for coal is forecasted to be around 90 years. In this work, the process to produce SNG by means of coal-entrained flow gasifiers is modeled under thermochemical equilibrium with the Gibbs free energy approach. The model was developed using a complete and comprehensive Aspen Plus model. Two typical technologies used in entrained flow gasifiers such as coal dry and coal slurry are modeled and simulated. Emphasis is put on interactions between the fuel feeding technology and selected energy output parameters of coal-SNG process, that is, energy efficiencies, power, and SNG quality. It was found that coal rank does not significantly affect energy indicators such as cold gas, process, and global efficiencies. However, feeding technology clearly has an effect on the process due to the gasifying agent. Simulations results are compared against available technical data with good accuracy. Thus, the proposed model is considered as a versatile and useful computational tool to study and optimize the coal to SNG process.

Hybrid2 - The hybrid power system simulation model

Energy Technology Data Exchange (ETDEWEB)

Baring-Gould, E.I.; Green, H.J.; Dijk, V.A.P. van [National Renewable Energy Lab., Golden, CO (United States); Manwell, J.F. [Univ. of Massachusetts, Amherst, MA (United States)

1996-12-31

There is a large-scale need and desire for energy in remote communities, especially in the developing world; however the lack of a user friendly, flexible performance prediction model for hybrid power systems incorporating renewables hindered the analysis of hybrids as options to conventional solutions. A user friendly model was needed with the versatility to simulate the many system locations, widely varying hardware configurations, and differing control options for potential hybrid power systems. To meet these ends, researchers from the National Renewable Energy Laboratory (NREL) and the University of Massachusetts (UMass) developed the Hybrid2 software. This paper provides an overview of the capabilities, features, and functionality of the Hybrid2 code, discusses its validation and future plans. Model availability and technical support provided to Hybrid2 users are also discussed. 12 refs., 3 figs., 4 tabs.

Marine Fish Hybridization

KAUST Repository

He, Song

2017-04-01

Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

Intuitionistic hybrid logic

DEFF Research Database (Denmark)

Braüner, Torben

2011-01-01

Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

Design optimization of single mixed refrigerant LNG process using a hybrid modified coordinate descent algorithm

Science.gov (United States)

Qyyum, Muhammad Abdul; Long, Nguyen Van Duc; Minh, Le Quang; Lee, Moonyong

2018-01-01

Design optimization of the single mixed refrigerant (SMR) natural gas liquefaction (LNG) process involves highly non-linear interactions between decision variables, constraints, and the objective function. These non-linear interactions lead to an irreversibility, which deteriorates the energy efficiency of the LNG process. In this study, a simple and highly efficient hybrid modified coordinate descent (HMCD) algorithm was proposed to cope with the optimization of the natural gas liquefaction process. The single mixed refrigerant process was modeled in Aspen Hysys® and then connected to a Microsoft Visual Studio environment. The proposed optimization algorithm provided an improved result compared to the other existing methodologies to find the optimal condition of the complex mixed refrigerant natural gas liquefaction process. By applying the proposed optimization algorithm, the SMR process can be designed with the 0.2555 kW specific compression power which is equivalent to 44.3% energy saving as compared to the base case. Furthermore, in terms of coefficient of performance (COP), it can be enhanced up to 34.7% as compared to the base case. The proposed optimization algorithm provides a deep understanding of the optimization of the liquefaction process in both technical and numerical perspectives. In addition, the HMCD algorithm can be employed to any mixed refrigerant based liquefaction process in the natural gas industry.

Energy Efficiency Comparison between Hydraulic Hybrid and Hybrid Electric Vehicles

Directory of Open Access Journals (Sweden)

Jia-Shiun Chen

2015-05-01

Full Text Available Conventional vehicles tend to consume considerable amounts of fuel, which generates exhaust gases and environmental pollution during intermittent driving cycles. Therefore, prospective vehicle designs favor improved exhaust emissions and energy consumption without compromising vehicle performance. Although pure electric vehicles feature high performance and low pollution characteristics, their limitations are their short driving range and high battery costs. Hybrid electric vehicles (HEVs are comparatively environmentally friendly and energy efficient, but cost substantially more compared with conventional vehicles. Hydraulic hybrid vehicles (HHVs are mainly operated using engines, or using alternate combinations of engine and hydraulic power sources while vehicles accelerate. When the hydraulic system accumulator is depleted, the conventional engine reengages; concurrently, brake-regenerated power is recycled and reused by employing hydraulic motor–pump modules in circulation patterns to conserve fuel and recycle brake energy. This study adopted MATLAB Simulink to construct complete HHV and HEV models for backward simulations. New European Driving Cycles were used to determine the changes in fuel economy. The output of power components and the state-of-charge of energy could be retrieved. Varying power component models, energy storage component models, and series or parallel configurations were combined into seven different vehicle configurations: the conventional manual transmission vehicle, series hybrid electric vehicle, series hydraulic hybrid vehicle, parallel hybrid electric vehicle, parallel hydraulic hybrid vehicle, purely electric vehicle, and hydraulic-electric hybrid vehicle. The simulation results show that fuel consumption was 21.80% lower in the series hydraulic hybrid vehicle compared to the series hybrid electric vehicle; additionally, fuel consumption was 3.80% lower in the parallel hybrid electric vehicle compared to the

Hybride textuelle Strukturen und hybride textuelle Einheiten. Ein ...

African Journals Online (AJOL)

carrying set of all hybrid hierarchical structures are element-heterogeneous whilst the structure- carrying set of all ... grams of hierarchical hybrid article structures, the nodes for those text segments that establish the hybrid status of .... der; d ∈ ArtA ⊣ G|WAr (= Artikelangabe, anhand derer das Genus (= G) und zugleich die ...

Removal of N-linked glycosylations at acidic pH by PNGase a facilitates hydrogen/deuterium exchange mass spectrometry analysis of N-Linked glycoproteins

DEFF Research Database (Denmark)

Jensen, Pernille Foged; Comamala, Gerard; Trelle, Morten Beck

2016-01-01

for analysis of the conformational dynamics of N-linked glycoproteins that utilizes the enzyme PNGase A for deglycosylation of labeled peptic N-linked glycopeptides at HDX quench conditions, i.e., acidic pH and low temperature. PNGase A-based deglycosylation is thus performed after labeling (post...

A kinetic reaction model for biomass pyrolysis processes in Aspen Plus

International Nuclear Information System (INIS)

Peters, Jens F.; Banks, Scott W.; Bridgwater, Anthony V.; Dufour, Javier

2017-01-01

Highlights: • Predictive kinetic reaction model applicable to any lignocellulosic feedstock. • Calculates pyrolysis yields and product composition as function of reactor conditions. • Detailed modelling of product composition (33 model compounds for the bio-oil). • Good agreement with literature regarding yield curves and product composition. • Successful validation with pyrolysis experiments in bench scale fast pyrolysis rig. - Abstract: This paper presents a novel kinetic reaction model for biomass pyrolysis processes. The model is based on the three main building blocks of lignocellulosic biomass, cellulose, hemicellulose and lignin and can be readily implemented in Aspen Plus and easily adapted to other process simulation software packages. It uses a set of 149 individual reactions that represent the volatilization, decomposition and recomposition processes of biomass pyrolysis. A linear regression algorithm accounts for the secondary pyrolysis reactions, thus allowing the calculation of slow and intermediate pyrolysis reactions. The bio-oil is modelled with a high level of detail, using up to 33 model compounds, which allows for a comprehensive estimation of the properties of the bio-oil and the prediction of further upgrading reactions. After showing good agreement with existing literature data, our own pyrolysis experiments are reported for validating the reaction model. A beech wood feedstock is subjected to pyrolysis under well-defined conditions at different temperatures and the product yields and compositions are determined. Reproducing the experimental pyrolysis runs with the simulation model, a high coincidence is found for the obtained fraction yields (bio-oil, char and gas), for the water content and for the elemental composition of the pyrolysis products. The kinetic reaction model is found to be suited for predicting pyrolysis yields and product composition for any lignocellulosic biomass feedstock under typical pyrolysis conditions

Hybrid platform. Economical hybrid drive for commercial vehicles; Hybrid Plattform. Wirtschaftlicher Hybridantrieb fuer Nutzfahrzeuge

Energy Technology Data Exchange (ETDEWEB)

Wallner, S.; Lamke, M.; Mohr, M.; Sedlacek, M.; Speck, F.D. [ZF Friedrichshafen AG, Friedrichshafen (Germany)

2011-07-01

Up to now, hybrid systems have been adapted to their specific requirements in the various applications for trucks, buses as well as mobile and building machines. From a technical point of view, this does indeed result in optimized hybrid drives for each single vehicle application, but due to small volumes, such single developments are critical from a business point of view. ZF Friedrichshafen AG is providing a solution to the technical and economical requirements of the cost-sensitive CV segment in the form of a modular CV parallel hybrid platform composed of a hybrid module system, an inverter, a battery system, and a hybrid software integrated into the overall vehicle. Thanks to the intelligent combination of assemblies and the use of as many identical parts as possible, platforms are realized which cover power ranges between 60 and 120 kW, voltage ranges between 350 and 650 V, and battery capacities between 2 and 4 kWh. The dimensions of the platform elements are such that integration into the diverse commercial vehicle applications is made easy. The hybrid software required for the vehicle-specific functions is also configurable for the mentioned CV applications. (orig.)

Fusion-fission hybrid reactors

International Nuclear Information System (INIS)

Greenspan, E.

1984-01-01

This chapter discusses the range of characteristics attainable from hybrid reactor blankets; blanket design considerations; hybrid reactor designs; alternative fuel hybrid reactors; multi-purpose hybrid reactors; and hybrid reactors and the energy economy. Hybrid reactors are driven by a fusion neutron source and include fertile and/or fissile material. The fusion component provides a copious source of fusion neutrons which interact with a subcritical fission component located adjacent to the plasma or pellet chamber. Fissile fuel and/or energy are the main products of hybrid reactors. Topics include high F/M blankets, the fissile (and tritium) breeding ratio, effects of composition on blanket properties, geometrical considerations, power density and first wall loading, variations of blanket properties with irradiation, thermal-hydraulic and mechanical design considerations, safety considerations, tokamak hybrid reactors, tandem-mirror hybrid reactors, inertial confinement hybrid reactors, fusion neutron sources, fissile-fuel and energy production ability, simultaneous production of combustible and fissile fuels, fusion reactors for waste transmutation and fissile breeding, nuclear pumped laser hybrid reactors, Hybrid Fuel Factories (HFFs), and scenarios for hybrid contribution. The appendix offers hybrid reactor fundamentals. Numerous references are provided

Hybrid reactors

International Nuclear Information System (INIS)

Moir, R.W.

1980-01-01

The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of 233 U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m -2 , and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid

Simulation of the SSC refrigeration system using the ASPEN/SP process simulator

International Nuclear Information System (INIS)

Rasson, J.; Dweck, J.

1990-01-01

The SSC Magnet must be maintained at a superconducting temperature of 4 K. The proposed refrigeration cooling processes consist of fairly simple closed cycles which take advantage of the Joule-Thompson effect via a series of expansions and compressions of helium gas which has been precooled by liquid nitrogen. The processes currently under consideration consist of three cycles, the 20 K shield cooling, the 4.0 K helium refrigerator and the helium liquefier. The process units which are to be employed are compressors, turbines, expanders, mixers, flashes, two stream heat exchangers and multiple stream heat exchangers. The cycles are to be operated at or near steady state. Due to the large number of competing cooling sector designs to be considered and the high capital and operating costs of the proposed processes, the SSC Laboratory requires a software tool for the validation and optimization of the individual designs and for the performance of cost-benefit analyses among competing designs. Since these processes are steady state flow processes involving primarily standard unit operations, a decision was made to investigate the application of a commercial process simulator to the task. Several months of internal evaluations by the SSC Laboratory revealed that while the overall structure and calculation approach of a number of the commercial simulators were appropriate for this task, all were lacking essential capabilities in the areas of thermodynamic property calculations for cryogenic systems and modeling of complex, multiple stream heat exchangers. An acceptable thermodynamic model was provided and a series of simple, but three software vendors. Based on the results of the benchmark tests, the ASPEN/SP process simulator was selected for future modeling work. 2 refs., 4 figs

Corporate Hybrid Bonds

OpenAIRE

Ahlberg, Johan; Jansson, Anton

2016-01-01

Hybrid securities do not constitute a new phenomenon in the Swedish capital markets. Most commonly, hybrids issued by Swedish real estate companies in recent years are preference shares. Corporate hybrid bonds on the other hand may be considered as somewhat of a new-born child in the family of hybrid instruments. These do, as all other hybrid securities, share some equity-like and some debt-like characteristics. Nevertheless, since 2013 the interest for the instrument has grown rapidly and ha...

Identification and characterization of peptide: N- glycanase from Dictyostelium discoideum

Directory of Open Access Journals (Sweden)

Gosain Anuradha

2012-06-01

Full Text Available Abstract Background Peptide: N- glycanase (PNGase enzyme cleaves oligosaccharides from the misfolded glycoproteins and prepares them for degradation. This enzyme plays a role in the endoplasmic reticulum associated degradation (ERAD pathway in yeast and mice but its biological importance and role in multicellular development remain largely unknown. Results In this study, the PNGase from the cellular slime mold, Dictyostelium discoideum (DdPNGase was identified based on the presence of a common TG (transglutaminase core domain and its sequence homology with the known PNGases. The domain architecture and the sequence comparison validated the presence of probable functional domains in DdPNGase. The tertiary structure matched with the mouse PNGase. Here we show that DdPNGase is an essential protein, required for aggregation during multicellular development and a knockout strain of it results in small sized aggregates, all of which did not form fruiting bodies. The in situ hybridization and RT-PCR results show higher level of expression during the aggregate stage. The expression gets restricted to the prestalk region during later developmental stages. DdPNGase is a functional peptide:N-glycanase enzyme possessing deglycosylation activity, but does not possess any significant transamidation activity. Conclusions We have identified and characterized a novel PNGase from D. discoideum and confirmed its deglycosylation activity. The results emphasize the importance of PNGase in aggregation during multicellular development of this organism.

Cost evaluation of cellulase enzyme for industrial-scale cellulosic ethanol production based on rigorous Aspen Plus modeling.

Science.gov (United States)

Liu, Gang; Zhang, Jian; Bao, Jie

2016-01-01

Cost reduction on cellulase enzyme usage has been the central effort in the commercialization of fuel ethanol production from lignocellulose biomass. Therefore, establishing an accurate evaluation method on cellulase enzyme cost is crucially important to support the health development of the future biorefinery industry. Currently, the cellulase cost evaluation methods were complicated and various controversial or even conflict results were presented. To give a reliable evaluation on this important topic, a rigorous analysis based on the Aspen Plus flowsheet simulation in the commercial scale ethanol plant was proposed in this study. The minimum ethanol selling price (MESP) was used as the indicator to show the impacts of varying enzyme supply modes, enzyme prices, process parameters, as well as enzyme loading on the enzyme cost. The results reveal that the enzyme cost drives the cellulosic ethanol price below the minimum profit point when the enzyme is purchased from the current industrial enzyme market. An innovative production of cellulase enzyme such as on-site enzyme production should be explored and tested in the industrial scale to yield an economically sound enzyme supply for the future cellulosic ethanol production.

Cardiac hybrid imaging

Energy Technology Data Exchange (ETDEWEB)

Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

2014-05-15

Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

Global transcriptomic profiling of aspen trees under elevated [CO2] to identify potential molecular mechanisms responsible for enhanced radial growth.

Science.gov (United States)

Wei, Hairong; Gou, Jiqing; Yordanov, Yordan; Zhang, Huaxin; Thakur, Ramesh; Jones, Wendy; Burton, Andrew

2013-03-01

Aspen (Populus tremuloides) trees growing under elevated [CO(2)] at a free-air CO(2) enrichment (FACE) site produced significantly more biomass than control trees. We investigated the molecular mechanisms underlying the observed increase in biomass by producing transcriptomic profiles of the vascular cambium zone (VCZ) and leaves, and then performed a comparative study to identify significantly changed genes and pathways after 12 years exposure to elevated [CO(2)]. In leaves, elevated [CO(2)] enhanced expression of genes related to Calvin cycle activity and linked pathways. In the VCZ, the pathways involved in cell growth, cell division, hormone metabolism, and secondary cell wall formation were altered while auxin conjugation, ABA synthesis, and cytokinin glucosylation and degradation were inhibited. Similarly, the genes involved in hemicellulose and pectin biosynthesis were enhanced, but some genes that catalyze important steps in lignin biosynthesis pathway were inhibited. Evidence from systemic analysis supported the functioning of multiple molecular mechanisms that underpin the enhanced radial growth in response to elevated [CO(2)].

Simulation of Synthesis Gas Production from Steam Oxygen Gasification of Colombian Coal Using Aspen Plus®

Directory of Open Access Journals (Sweden)

Jorge E. Preciado

2012-11-01

Full Text Available A steady state simulation of syngas production from a Steam Oxygen Gasification process using commercial technologies was performed using Aspen Plus®. For the simulation, the average proximate and ultimate compositions of bituminous coal obtained from the Colombian Andean region were employed. The simulation was applied to conduct sensitivity analyses in the O2 to coal mass ratio, coal slurry concentration, WGS operating temperature and WGS steam to dry gas molar ratio (SDG over the key parameters: syngas molar composition, overall CO conversion in the WGS reactors, H2 rich-syngas lower heating value (LHV and thermal efficiency. The achieved information allows the selection of critical operating conditions leading to improve system efficiency and environmental performance. The results indicate that the oxygen to carbon ratio is a key variable as it affects significantly both the LHV and thermal efficiency. Nevertheless, the process becomes almost insensitive to SDG values higher than 2. Finally, a thermal efficiency of 62.6% can be reached. This result corresponds to a slurry solid concentration of 0.65, a WGS process SDG of 0.59, and a LTS reactor operating temperature of 473 K. With these fixed variables, a syngas with H2 molar composition of 92.2% and LHV of 12 MJ Nm−3 was attained.

Full employment and competition in the Aspen economic model: implications for modeling acts of terrorism.

Energy Technology Data Exchange (ETDEWEB)

Sprigg, James A.; Ehlen, Mark Andrew

2004-11-01

Acts of terrorism could have a range of broad impacts on an economy, including changes in consumer (or demand) confidence and the ability of productive sectors to respond to changes. As a first step toward a model of terrorism-based impacts, we develop here a model of production and employment that characterizes dynamics in ways useful toward understanding how terrorism-based shocks could propagate through the economy; subsequent models will introduce the role of savings and investment into the economy. We use Aspen, a powerful economic modeling tool developed at Sandia, to demonstrate for validation purposes that a single-firm economy converges to the known monopoly equilibrium price, output, and employment levels, while multiple-firm economies converge toward the competitive equilibria typified by lower prices and higher output and employment. However, we find that competition also leads to churn by consumers seeking lower prices, making it difficult for firms to optimize with respect to wages, prices, and employment levels. Thus, competitive firms generate market ''noise'' in the steady state as they search for prices and employment levels that will maximize profits. In the context of this model, not only could terrorism depress overall consumer confidence and economic activity but terrorist acts could also cause normal short-run dynamics to be misinterpreted by consumers as a faltering economy.

The plus-hybrid effect on the grain yield of two ZP maize hybrids

Directory of Open Access Journals (Sweden)

Božinović Sofija

2010-01-01

Full Text Available The combined effect of cytoplasmic male sterility and xenia on maize hybrid traits is referred to as the plus-hybrid effect. Two studied ZP hybrids differently responded to this effect for grain yield. All plus-hybrid combinations of the firstly observed hybrid had a higher yield than their fertile counterparts, but not significantly, while only one combination of the second hybrid positively responded, also without statistical significance. It seems that the observed effect mostly depended on the genotype of the female component.

Fluxes of CH4 and N2O in aspen stands grown under ambient and twice-ambient CO2

DEFF Research Database (Denmark)

Ambus, P.; Robertson, G.P.

1999-01-01

Elevated atmospheric CO2 has the potential to change below-ground nutrient cycling and thereby alter the soil-atmosphere exchange of biogenic trace gases. We measured fluxes of CH4 and N2O in trembling aspen (Populus tremuloides Michx.) stands grown in open-top chambers under ambient and twice......-ambient CO2 concentrations crossed with `high' and low soil-N conditions. Flux measurements with small static chambers indicated net CH4 oxidation in the open-top chambers. Across dates, CH4 oxidation activity was significantly (P CO2 (8.7 mu g CH4-C m(-2) h(-1)) than...... with elevated CO2 (6.5 mu g CH4-C m(-2) h(-1)) in the low N soil. Likewise, across dates and soil N treatments CH4 was oxidized more rapidly (P CO2 (9.5 mu g CH4-C m(-2) h(-1)) than in chambers with elevated CO2 (8.8 mu g CH4-C m(-2) h(-1)). Methane oxidation in soils incubated...

Toronto hybrid taxi pilot

International Nuclear Information System (INIS)

Stevens, M.; Marans, B.

2009-10-01

This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO 2 ) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO 2 emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

Toronto hybrid taxi pilot

Energy Technology Data Exchange (ETDEWEB)

Stevens, M. [CrossChasm Technologies, Cambridge, ON (Canada); Marans, B. [Toronto Atmospheric Fund, ON (Canada)

2009-10-15

This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO{sub 2}) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO{sub 2} emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

Experimental Investigation and Aspen Plus Simulation of the MSW Pyrolysis Process

Science.gov (United States)

Ansah, Emmanuel

Municipal solid waste (MSW) is a potential feedstock for producing transportation fuels because it is readily available using an existing collection/transportation infrastructure and fees are provided by the suppliers or government agencies to treat MSW. North Carolina with a population of 9.4 millions generates 3.629 million metric tons of MSW each year, which contains about 113,396,356 TJs of energy. The average moisture content of MSW samples is 44.3% on a wet basis. About 77% of the dry MSW mass is combustible components including paper, organics, textile and plastics. The average heating values of MSW were 9.7, 17.5, and 22.7 MJ/kg on a wet basis, dry basis and dry combustible basis, respectively. The MSW generated in North Carolina can produce 7.619 million barrels of crude bio-oil or around 4% of total petroleum consumption in North Carolina. MSW can be thermally pyrolyzed into bio-oil in the absence of oxygen or air at a temperature of 500°C or above. As bio-oil can be easily stored and transported, compared to bulky MSW, landfill gas and electricity, pyrolysis offers significant logistical and economic advantages over landfilling and other thermal conversion processes such as combustion and gasification. Crude bio-oils produced from the pyrolysis of MSW can be further refined to transportation fuels in existing petroleum refinery facilities. The objective of this research is to analyze the technical and economic feasibility of pyrolyzing MSW into liquid transportation fuels. A combined thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC) instrument, which can serve as a micro-scale pyrolysis reactor, was used to simultaneously determine the degradation characteristics of MSW during pyrolysis. An ASPEN Plus-based mathematical model was further developed to analyze the technical and economic feasibility of pyrolysing of MSW into liquid transportation fuels in fixed bed reactors at varying operating conditions

Continuity controlled Hybrid Automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation

Simulación y validación de modelos de destilación por lotes usando Aspen Batch Modeler: recuperación de epóxido de limoneno

OpenAIRE

Yeison Agudelo; Rolando Barrera Zapata

2016-01-01

Se desarrolló el modelado y simulación de una columna de destilación por lotes para la recuperación de epóxido de limoneno de una mezcla multicomponente, usando el software especializado Aspen Batch Modeler. Para la validación de los modelos se desarrolló el proceso experimental en un equipo de roto-evaporación, donde se varió la composición inicial de la mezcla, temperatura y presión de operación. La composición final de fondos y destilado se determinó a través de cromatografía de gases. Los...

Hybrid systems, optimal control and hybrid vehicles theory, methods and applications

CERN Document Server

Böhme, Thomas J

2017-01-01

This book assembles new methods showing the automotive engineer for the first time how hybrid vehicle configurations can be modeled as systems with discrete and continuous controls. These hybrid systems describe naturally and compactly the networks of embedded systems which use elements such as integrators, hysteresis, state-machines and logical rules to describe the evolution of continuous and discrete dynamics and arise inevitably when modeling hybrid electric vehicles. They can throw light on systems which may otherwise be too complex or recondite. Hybrid Systems, Optimal Control and Hybrid Vehicles shows the reader how to formulate and solve control problems which satisfy multiple objectives which may be arbitrary and complex with contradictory influences on fuel consumption, emissions and drivability. The text introduces industrial engineers, postgraduates and researchers to the theory of hybrid optimal control problems. A series of novel algorithmic developments provides tools for solving engineering pr...

Continuity Controlled Hybrid Automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2004-01-01

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

Continuity controlled hybrid automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2004-01-01

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

Continuity controlled hybrid automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2006-01-01

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

Hybrid functional pseudopotentials

Science.gov (United States)

Yang, Jing; Tan, Liang Z.; Rappe, Andrew M.

2018-02-01

The consistency between the exchange-correlation functional used in pseudopotential construction and in the actual density functional theory calculation is essential for the accurate prediction of fundamental properties of materials. However, routine hybrid density functional calculations at present still rely on generalized gradient approximation pseudopotentials due to the lack of hybrid functional pseudopotentials. Here, we present a scheme for generating hybrid functional pseudopotentials, and we analyze the importance of pseudopotential density functional consistency for hybrid functionals. For the PBE0 hybrid functional, we benchmark our pseudopotentials for structural parameters and fundamental electronic gaps of the Gaussian-2 (G2) molecular dataset and some simple solids. Our results show that using our PBE0 pseudopotentials in PBE0 calculations improves agreement with respect to all-electron calculations.

From hybrid swarms to swarms of hybrids

Science.gov (United States)

Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

2014-01-01

Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

Hybride textuelle Strukturen und hybride textuelle Einheiten. Ein Beitrag zur Theorie der Wörterbuchform

Directory of Open Access Journals (Sweden)

Herbert Ernst Wiegand

2011-10-01

Full Text Available

ZUSAMMENFASSUNG: In diesem Beitrag wird die Bildung, Darstellung und Leistung von hybriden textuellen Strukturen, die akzessive Einträge aufweisen, am Beispiel von Wörterbuchartikeln behandelt sowie erklärt, welche Eigenschaften hybride textuelle Einheiten haben. Ein Wörterbuchartikel eines Printwörterbuchs weist immer dann neben einer hierarchischen reinen eine hierarchische hybride Textkonstituentenstruktur auf, wenn in ihm mindestens ein funktionaler Angabezusatz auftritt, z.B. ein oben oder unten erweiternder oder ein binnenerweiternder. Da funktionale Angabezusätze Textsegmente mit Angabefunktion aber ohne Textkonstituentenstatus sind, werden sie durch nichtfunktionale Segmentation ermittelt, so dass neben funktionalen auch nichtfunktionale Textsegmente gegeben sind, die dann bei der Strukturbildung in die Trägermengen eingehen, so dass die Trägermengen aller hybriden hierarchischen Strukturen elementenheterogen, während die Trägermengen aller hierarchischen reinen Strukturen elementenhomogen sind. In den Strukturgraphen für hierarchische hybride Artikelstrukturen sind dann die Knoten für diejenigen Textsegmente, die den Hybridstatus der Strukturen bewirken, entweder durch Pfeilkanten für die textarchitektonischen oberhalb/unterhalb-Relationen mit den Knoten für die Textkonstituenten verbunden, so dass die Strukturgraphen architektonisch angereichert sind, oder durch besonders markierte Kanten, die die Knoten für die nichtfunktionalen Textsegmente und die für die binnenerweiternden funktionalen Angabezusätze mit den Knoten für die Textkonstituenten verbinden. Zu jedem Typ von hierarchischer reiner Artikelstruktur gehören mehrere Typen von hybriden Artikelstrukturen; entsprechendes gilt für hierarchische reine Angabestrukturen. Nur eine Auswahl aus den Typologien der hybriden Artikel- und Angabestrukturen wird behandelt sowie eine kleine Auswahl von hybriden textuellen Einheiten, die kriteriale Eigenschaften von zwei

Human hybrid hybridoma

Energy Technology Data Exchange (ETDEWEB)

Tiebout, R.F.; van Boxtel-Oosterhof, F.; Stricker, E.A.M.; Zeijlemaker, W.P.

1987-11-15

Hybrid hybridomas are obtained by fusion of two cells, each producing its own antibody. Several authors have reported the construction of murine hybrid hybridomas with the aim to obtain bispecific monoclonal antibodies. The authors have investigated, in a model system, the feasibility of constructing a human hybrid hybridoma. They fused two monoclonal cell lines: an ouabain-sensitive and azaserine/hypoxanthine-resistant Epstein-Barr virus-transformed human cell line that produces an IgG1kappa antibody directed against tetanus toxiod and an azaserine/hypoxanthine-sensitive and ouabain-resistant human-mouse xenohybrid cell line that produces a human IgG1lambda antibody directed against hepatitis-B surface antigen. Hybrid hybridoma cells were selected in culture medium containing azaserine/hypoxanthine and ouabain. The hybrid nature of the secreted antibodies was analyzed by means of two antigen-specific immunoassay. The results show that it is possible, with the combined use of transformation and xenohybridization techniques, to construct human hybrid hybridomas that produce bispecific antibodies. Bispecific antibodies activity was measured by means of two radioimmunoassays.

Simulation of the Stabilization Unit Refinery “Hermanos Díaz” Using Aspen Hysys 8.0

Directory of Open Access Journals (Sweden)

Thayset Mariño-Peacok

2016-07-01

Full Text Available In this paper a study of the production of liquefied petroleum gas is carried out in the Stabilization Unit refinery “Hermanos Díaz”. Implementation of this process was conducted in the simulator Aspen Hysys 8.0 with the aim of developing a simulation that would increase the efficiency of this plant. Different alternatives are evaluated using the simulator tool Databook, as were the analysis of the temperature and pressure and its influence on the flow of the compounds of interest in the separators; the number of trays and the feed tray to the distillation column and its influence on the energy of the condenser and reboiler. It was determined that at 44°C and 160 kPa in the separator D-120 and at 34,5 °C and 738.8 kPa in the separator D-109 ensures good performance of the process. In addition it was found that with 50 trays and a feed tray 27 in the distillation tower T-104 guarantee lower consumption of energy (1,4*10 7 kJ/kmol and 1,5*107 kJ/kmol for the condenser and reboiler respectively. It was shown that an increased flow of unstabilized light naphtha fed to the plant, leads to increased efficiency of the unit. The simulation of the process led to raise the efficiency of the plant because the flow of liquefied petroleum gas increased in 11.79% to quality established.

Dying piece by piece: carbohydrate dynamics in aspen (Populus tremuloides) seedlings under severe carbon stress.

Science.gov (United States)

Wiley, Erin; Hoch, Günter; Landhäusser, Simon M

2017-11-02

Carbon starvation as a mechanism of tree mortality is poorly understood. We exposed seedlings of aspen (Populus tremuloides) to complete darkness at 20 or 28 °C to identify minimum non-structural carbohydrate (NSC) concentrations at which trees die and to see if these levels vary between organs or with environmental conditions. We also first grew seedlings under different shade levels to determine if size affects survival time under darkness due to changes in initial NSC concentration and pool size and/or respiration rates. Darkness treatments caused a gradual dieback of tissues. Even after half the stem had died, substantial starch reserves were still present in the roots (1.3-3% dry weight), indicating limitations to carbohydrate remobilization and/or transport during starvation in the absence of water stress. Survival time decreased with increased temperature and with increasing initial shade level, which was associated with smaller biomass, higher respiration rates, and initially smaller NSC pool size. Dead tissues generally contained no starch, but sugar concentrations were substantially above zero and differed between organs (~2% in stems up to ~7.5% in leaves) and, at times, between temperature treatments and initial, pre-darkness shade treatments. Minimum root NSC concentrations were difficult to determine because dead roots quickly began to decompose, but we identify 5-6% sugar as a potential threshold for living roots. This variability may complicate efforts to identify critical NSC thresholds below which trees starve. © Society for Experimental Biology 2017.

Henkin and Hybrid Logic

DEFF Research Database (Denmark)

Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria

2014-01-01

Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

Hybrid breeding in wheat: technologies to improve hybrid wheat seed production.

Science.gov (United States)

Whitford, Ryan; Fleury, Delphine; Reif, Jochen C; Garcia, Melissa; Okada, Takashi; Korzun, Viktor; Langridge, Peter

2013-12-01

Global food security demands the development and delivery of new technologies to increase and secure cereal production on finite arable land without increasing water and fertilizer use. There are several options for boosting wheat yields, but most offer only small yield increases. Wheat is an inbred plant, and hybrids hold the potential to deliver a major lift in yield and will open a wide range of new breeding opportunities. A series of technological advances are needed as a base for hybrid wheat programmes. These start with major changes in floral development and architecture to separate the sexes and force outcrossing. Male sterility provides the best method to block self-fertilization, and modifying the flower structure will enhance pollen access. The recent explosion in genomic resources and technologies provides new opportunities to overcome these limitations. This review outlines the problems with existing hybrid wheat breeding systems and explores molecular-based technologies that could improve the hybrid production system to reduce hybrid seed production costs, a prerequisite for a commercial hybrid wheat system.

Contrasting Effects of Cattle Grazing Intensity on Upland-Nesting Duck Production at Nest and Field Scales in the Aspen Parkland, Canada

Directory of Open Access Journals (Sweden)

Jeffrey M. Warren

2008-12-01

Full Text Available The Aspen Parkland of Canada is one of the most important breeding areas for temperate nesting ducks in North America. The region is dominated by agricultural land use, with approximately 9.3 million ha in pasture land for cattle grazing. However, the effects of using land for cattle grazing on upland-nesting duck production are poorly understood. The current study was undertaken during 2001 and 2002 to investigate how nest density and nesting success of upland-nesting ducks varied with respect to the intensity of cattle grazing in the Aspen Parkland. We predicted that the removal and trampling of vegetation through cattle grazing would reduce duck nest density. Both positive and negative responses of duck nesting success to grazing have been reported in previous studies, leading us to test competing hypotheses that nesting success would (1 decline linearly with grazing intensity or (2 peak at moderate levels of grazing. Nearly 3300 ha of upland cover were searched during the study. Despite extensive and severe drought, nest searches located 302 duck nests. As predicted, nest density was higher in fields with lower grazing intensity and higher pasture health scores. A lightly grazed field with a pasture score of 85 out of a possible 100 was predicted to have 16.1 nests/100 ha (95% CI = 11.7-22.1, more than five times the predicted nest density of a heavily grazed field with a pasture score of 58 (3.3 nests/100 ha, 95% CI = 2.2-4.5. Nesting success was positively related to nest-site vegetation density across most levels of grazing intensity studied, supporting our hypothesis that reductions in vegetation caused by grazing would negatively affect nesting success. However, nesting success increased with grazing intensity at the field scale. For example, nesting success for a well-concealed nest in a lightly grazed field was 11.6% (95% CI = 3.6-25.0%, whereas nesting success for a nest with the same level of nest-site vegetation in a heavily grazed

Wood production potential in poplar plantations in Sweden

International Nuclear Information System (INIS)

Christersson, Lars

2010-01-01

Shortage of oil, large variations in exports from Russia of wood to Europe, plenty of abandoned agriculture land, new ideas about a more intensive silviculture; these circumstances are driving forces in Sweden for planting fast-growing poplar and hybrid aspen clones on suitable land. The advantage of such trees is that the wood can be used for both energy (heat, biofuels, electricity), paper and for construction. Poplar clones bred in the USA and Belgium, and older hybrid aspen clones from Sweden, together with new poplar clones collected and selected for Swedish conditions from British Columbia, Canada, were planted during the 1990s in south and central Sweden. The stem diameters and heights of the trees have been measured during the last 10 years and the woody biomass production above ground has been calculated. MAI for all the plantations is 10-31 m 3 or 3-10 ton DM per hectare with the highest annual woody production of 45 m 3 or 15 ton DM per hectare in some years in a very dense plantation in the most southern part of Sweden. All the plantations have been fenced for at least the first ten years. The damage has been caused by stem canker, insects, leaf rust and by moose after removal of the fences. The possibilities for the use of poplar plantations as energy forest and vegetation filters are discussed. (author)

Pectin methyl esterase inhibits intrusive and symplastic cell growth in developing wood cells of Populus.

Science.gov (United States)

Siedlecka, Anna; Wiklund, Susanne; Péronne, Marie-Amélie; Micheli, Fabienne; Lesniewska, Joanna; Sethson, Ingmar; Edlund, Ulf; Richard, Luc; Sundberg, Björn; Mellerowicz, Ewa J

2008-02-01

Wood cells, unlike most other cells in plants, grow by a unique combination of intrusive and symplastic growth. Fibers grow in diameter by diffuse symplastic growth, but they elongate solely by intrusive apical growth penetrating the pectin-rich middle lamella that cements neighboring cells together. In contrast, vessel elements grow in diameter by a combination of intrusive and symplastic growth. We demonstrate that an abundant pectin methyl esterase (PME; EC 3.1.1.11) from wood-forming tissues of hybrid aspen (Populus tremula x tremuloides) acts as a negative regulator of both symplastic and intrusive growth of developing wood cells. When PttPME1 expression was up- and down-regulated in transgenic aspen trees, the PME activity in wood-forming tissues was correspondingly altered. PME removes methyl ester groups from homogalacturonan (HG) and transgenic trees had modified HG methylesterification patterns, as demonstrated by two-dimensional nuclear magnetic resonance and immunostaining using PAM1 and LM7 antibodies. In situ distributions of PAM1 and LM7 epitopes revealed changes in pectin methylesterification in transgenic trees that were specifically localized in expanding wood cells. The results show that en block deesterification of HG by PttPME1 inhibits both symplastic growth and intrusive growth. PttPME1 is therefore involved in mechanisms determining fiber width and length in the wood of aspen trees.

Genetic basis to hybrid inviability is more complex than hybrid male sterility in Caenorhabditis nematodes.

Science.gov (United States)

Bundus, Joanna D; Wang, Donglin; Cutter, Asher D

2018-04-07

Hybrid male sterility often evolves before female sterility or inviability of hybrids, implying that the accumulation of divergence between separated lineages should lead hybrid male sterility to have a more polygenic basis. However, experimental evidence is mixed. Here, we use the nematodes Caenorhabditis remanei and C. latens to characterize the underlying genetic basis of asymmetric hybrid male sterility and hybrid inviability. We demonstrate that hybrid male sterility is consistent with a simple genetic basis, involving a single X-autosome incompatibility. We also show that hybrid inviability involves more genomic compartments, involving diverse nuclear-nuclear incompatibilities, a mito-nuclear incompatibility, and maternal effects. These findings demonstrate that male sensitivity to genetic perturbation may be genetically simple compared to hybrid inviability in Caenorhabditis and motivates tests of generality for the genetic architecture of hybrid incompatibility across the breadth of phylogeny.

Fusion-fission hybrids: environmental aspects and their role in hybrid rationale

International Nuclear Information System (INIS)

Holdren, J.P.

1981-01-01

The rationale for developing hybrids depends on real or perceived liabilities of relying on pure fission to do the same job. Quite possibly the main constraint on expanded use of fission will be neither lack of fuel nor high costs, but perceived environmental liabilities - radioactive wastes, reactor safety, and links to nuclear weaponry. The environmental characteristics of hybrid systems and pure-fisson systems are compared here in detail. The findings are that significant environmental advantages for hybrids cannot now be demonstrated and may not exist. Therefore, if environmental drawbacks constrain the application of pure fission, hybrids probably also will be thus constrained

S 400 BlueHYBRID. First hybrid vehicle with Li-ion technology; S 400 BlueHYBRID. Erstes Hybridfahrzeug mit Li-Ionen-Technologie

Energy Technology Data Exchange (ETDEWEB)

Vollrath, Oliver; Armstrong, Neil; Schenk, Juergen; Bitsche, Otmar; Lamm, Arnold [Daimler AG, Stuttgart (Germany)

2009-07-01

Mercedes Benz advances the electrification of the drive strand in all performance classes and in all models from the start-stop system till to the full hybrid. Thereby, the S 400 BlueHYBRID presents the first Mercedes-Benz hybrid. Equipped with the characteristics of a start-stop system, with a recovery of the brake energy and with an electrical support of the drive, this hybrid obtains a saving of the consumption of approximately 20 %. By means of the design of the components and by means of the selection of a standard installation size, all hybrid-specific construction units in the vehicle porch could be arranged. Here, a special role comes to the used battery technology, since it became possible to arrange the hybrid battery in the size and the building area of a conventional starter battery accordingly.

High titer L-lactic acid production from corn stover with minimum wastewater generation and techno-economic evaluation based on Aspen plus modeling.

Science.gov (United States)

Liu, Gang; Sun, Jiaoe; Zhang, Jian; Tu, Yi; Bao, Jie

2015-12-01

Technological potentials of l-lactic acid production from corn stover feedstock were investigated by experimental and techno-economic studies. An optimal performance with 104.5 g/L in l-lactic acid titer and 71.5% in overall yield from cellulose in corn stover to l-lactic acid using an engineered Pediococcus acidilactici strain were obtained by overcoming several technical barriers. A rigorous Aspen plus model for l-lactic acid production starting from dry dilute acid pretreated and biodetoxified corn stover was developed. The techno-economic analysis shows that the minimum l-lactic acid selling price (MLSP) was $0.523 per kg, which was close to that of the commercial l-lactic acid produced from starch feedstock, and 24% less expensive than that of ethanol from corn stover, even though the xylose utilization was not considered. The study provided a prototype of industrial application and an evaluation model for high titer l-lactic acid production from lignocellulose feedstock. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hybrid quantum-classical master equations

International Nuclear Information System (INIS)

Diósi, Lajos

2014-01-01

We discuss hybrid master equations of composite systems, which are hybrids of classical and quantum subsystems. A fairly general form of hybrid master equations is suggested. Its consistency is derived from the consistency of Lindblad quantum master equations. We emphasize that quantum measurement is a natural example of exact hybrid systems. We derive a heuristic hybrid master equation of time-continuous position measurement (monitoring). (paper)

Mesoscale hybrid calibration artifact

Science.gov (United States)

Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

2010-09-07

A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

Hybrid Action Systems

DEFF Research Database (Denmark)

Ronkko, Mauno; Ravn, Anders P.

1997-01-01

a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

Hybridization and genome evolution I: The role of contingency during hybrid speciation

Directory of Open Access Journals (Sweden)

Fabrice EROUKHMANOFF, Richard I. BAILEY, Glenn-Peter SæTRE

2013-10-01

Full Text Available Homoploid hybrid speciation (HHS involves the recombination of two differentiated genomes into a novel, functional one without a change in chromosome number. Theoretically, there are numerous ways for two parental genomes to recombine. Hence, chance may play a large role in the formation of a hybrid species. If these genome combinations can evolve rapidly following hybridization and sympatric situations are numerous, recurrent homoploid hybrid speciation is a possibility. We argue that three different, but not mutually exclusive, types of contingencies could influence this process. First, many of these “hopeful monsters” of recombinant parent genotypes would likely have low fitness. Only specific combinations of parental genomic contributions may produce viable, intra-fertile hybrid species able to accommodate potential constraints arising from intragenomic conflict. Second, ecological conditions (competition, geography of the contact zones or the initial frequency of both parent species might favor different outcomes ranging from sympatric coexistence to the formation of hybrid swarms and ultimately hybrid speciation. Finally, history may also play an important role in promoting or constraining recurrent HHS if multiple hybridization events occur sequentially and parental divergence or isolation differs along this continuum. We discuss under which conditions HHS may occur multiple times in parallel and to what extent recombination and selection may fuse the parent genomes in the same or different ways. We conclude by examining different approaches that might help to solve this intriguing evolutionary puzzle [Current Zoology 59 (5: 667-674, 2013].　

Electrical potential-assisted DNA hybridization. How to mitigate electrostatics for surface DNA hybridization.

Science.gov (United States)

Tymoczko, Jakub; Schuhmann, Wolfgang; Gebala, Magdalena

2014-12-24

Surface-confined DNA hybridization reactions are sensitive to the number and identity of DNA capture probes and experimental conditions such as the nature and the ionic strength of the electrolyte solution. When the surface probe density is high or the concentration of bulk ions is much lower than the concentration of ions within the DNA layer, hybridization is significantly slowed down or does not proceed at all. However, high-density DNA monolayers are attractive for designing high-sensitivity DNA sensors. Thus, circumventing sluggish DNA hybridization on such interfaces allows a high surface concentration of target DNA and improved signal/noise ratio. We present potential-assisted hybridization as a strategy in which an external voltage is applied to the ssDNA-modified interface during the hybridization process. Results show that a significant enhancement of hybridization can be achieved using this approach.

First-Order Hybrid Logic

DEFF Research Database (Denmark)

Braüner, Torben

2011-01-01

Hybrid logic is an extension of modal logic which allows us to refer explicitly to points of the model in the syntax of formulas. It is easy to justify interest in hybrid logic on applied grounds, with the usefulness of the additional expressive power. For example, when reasoning about time one...... often wants to build up a series of assertions about what happens at a particular instant, and standard modal formalisms do not allow this. What is less obvious is that the route hybrid logic takes to overcome this problem often actually improves the behaviour of the underlying modal formalism....... For example, it becomes far simpler to formulate proof-systems for hybrid logic, and completeness results can be proved of a generality that is simply not available in modal logic. That is, hybridization is a systematic way of remedying a number of known deficiencies of modal logic. First-order hybrid logic...

Research on Hybrid Vehicle Drivetrain

Science.gov (United States)

Xie, Zhongzhi

Hybrid cars as a solution to energy saving, emission reduction measures, have received widespread attention. Motor drive system as an important part of the hybrid vehicles as an important object of study. Based on the hybrid electric vehicle powertrain control system for permanent magnet synchronous motor as the object of study. Can be applied to hybrid car compares the characteristics of traction motors, chose permanent magnet synchronous Motors as drive motors for hybrid vehicles. Building applications in hybrid cars in MATLAB/Simulink simulation model of permanent-magnet synchronous motor speed control system and analysis of simulation results.

Managing hybrid marketing systems.

Science.gov (United States)

Moriarty, R T; Moran, U

1990-01-01

As competition increases and costs become critical, companies that once went to market only one way are adding new channels and using new methods - creating hybrid marketing systems. These hybrid marketing systems hold the promise of greater coverage and reduced costs. But they are also hard to manage; they inevitably raise questions of conflict and control: conflict because marketing units compete for customers; control because new indirect channels are less subject to management authority. Hard as they are to manage, however, hybrid marketing systems promise to become the dominant design, replacing the "purebred" channel strategy in all kinds of businesses. The trick to managing the hybrid is to analyze tasks and channels within and across a marketing system. A map - the hybrid grid - can help managers make sense of their hybrid system. What the chart reveals is that channels are not the basic building blocks of a marketing system; marketing tasks are. The hybrid grid forces managers to consider various combinations of channels and tasks that will optimize both cost and coverage. Managing conflict is also an important element of a successful hybrid system. Managers should first acknowledge the inevitability of conflict. Then they should move to bound it by creating guidelines that spell out which customers to serve through which methods. Finally, a marketing and sales productivity (MSP) system, consisting of a central marketing database, can act as the central nervous system of a hybrid marketing system, helping managers create customized channels and service for specific customer segments.

Immunotherapy for Prostate Cancer with Gc Protein-Derived Macrophage-Activating Factor, GcMAF1

OpenAIRE

Yamamoto, Nobuto; Suyama, Hirofumi; Yamamoto, Nobuyuki

2008-01-01

Serum Gc protein (known as vitamin D3-binding protein) is the precursor for the principal macrophage-activating factor (MAF). The MAF precursor activity of serum Gc protein of prostate cancer patients was lost or reduced because Gc protein was deglycosylated by serum α-N-acetylgalactosaminidase (Nagalase) secreted from cancerous cells. Therefore, macrophages of prostate cancer patients having deglycosylated Gc protein cannot be activated, leading to immunosuppression. Stepwise treatment of pu...

Genome reorganization in Nicotiana asymmetric somatic hybrids analysed by in situ hybridization

International Nuclear Information System (INIS)

Parokonny, A.S.; Kenton, A.Y.; Gleba, Y.Y.; Bennett, M.D.

1992-01-01

In situ hybridization was used to examine genome reorganization in asymmetric somatic hybrids between Nicotiana plumbaginifolia and Nicotiana sylvestris obtained by fusion of gamma-irradiated protoplasts from one of the parents (donor) with non-irradiated protoplasts from the other (recipient). Probing with biotinylated total genomic DNA from either the donor or the recipient species unequivocally identified genetic material from both parents in 31 regenerant plants, each originating from a different nuclear hybrid colony. This method, termed genomic in situ hybridization (GISH), allowed intergenomic translocations containing chromosome segments from both species to be recognized in four regenerants. A probe homologous to the consensus sequence of the Arabidopsis thaliana telomeric repeat (5'-TTTAGGG-3')n, identified telomeres on all chromosomes, including 'mini-chromosomes' originating from the irradiated donor genome. Genomic in situ hybridization to plant chromosomes provides a rapid and reliable means of screening for recombinant genotypes in asymmetric somatic hybrids. Used in combination with other DNA probes, it also contributes to a greater understanding of the events responsible for genomic recovery and restabilization following genetic manipulation in vitro

Hybrid vehicle potential assessment. Volume 7: Hybrid vehicle review

Science.gov (United States)

Leschly, K. O.

1979-01-01

Review of hybrid vehicles built during the past ten years or planned to be built in the near future is presented. An attempt is made to classify and analyze these vehicles to get an overall picture of their key characteristics. The review includes onroad hybrid passenger cars, trucks, vans, and buses.

Generation of auroral kilometric radiation in upper hybrid wave-lower hybrid soliton interaction

International Nuclear Information System (INIS)

Pottelette, R.; Dubouloz, N.; Treumann, R.A.

1992-01-01

Sporadic bursts of auroral kilometric radiation (AKR) associated with strong bursty electrostatic turbulence in the vicinity of the lower hybrid frequency have been frequently recorded in the AKR source region by the Viking satellite. The variation time scale of these emissions is typically 1 s, long enough for lower hybrid waves to grow to amplitudes of several hundred millivolts per meter and to evolve nonlinearly into solitons. On the basis on these observations it is suggested that formation of lower hybrid solitons may play a role in the generation of AKR. A theoretical model is proposed which is based on the direct acceleration of electrons in the combined lower hybrid soliton and upper hybrid wave fields. The solitons act as sporadic, localized antennas allowing for efficient conversions of the electrostatic energy stored in upper hybrid waves into electromagnetic radiation at a frequency above the X mode cutoff. Excitation of lower hybrid waves is due to the presence of energetic electron beams in the auroral zone found to be associated with steep plasma density gradients. Upper hybrid waves can be excited by a population of energetic electrons with loss cone distributions. The power of the electromagnetic radiation obtained is only noticeable in regions where the plasma frequency is less than the electron gyrofrequency. The theory predicts spectral power densities of the order of 10 -11 to 10 -9 W m -2 Hz -1 in the source region, in good agreement with the Viking observations. The sporadic nature of the radiation derives from lower hybrid soliton collapses which occur on ∼1-s time scales

Craniomandibular form and body size variation of first generation mouse hybrids: A model for hominin hybridization.

Science.gov (United States)

Warren, Kerryn A; Ritzman, Terrence B; Humphreys, Robyn A; Percival, Christopher J; Hallgrímsson, Benedikt; Ackermann, Rebecca Rogers

2018-03-01

Hybridization occurs in a number of mammalian lineages, including among primate taxa. Analyses of ancient genomes have shown that hybridization between our lineage and other archaic hominins in Eurasia occurred numerous times in the past. However, we still have limited empirical data on what a hybrid skeleton looks like, or how to spot patterns of hybridization among fossils for which there are no genetic data. Here we use experimental mouse models to supplement previous studies of primates. We characterize size and shape variation in the cranium and mandible of three wild-derived inbred mouse strains and their first generation (F 1 ) hybrids. The three parent taxa in our analysis represent lineages that diverged over approximately the same period as the human/Neanderthal/Denisovan lineages and their hybrids are variably successful in the wild. Comparisons of body size, as quantified by long bone measurements, are also presented to determine whether the identified phenotypic effects of hybridization are localized to the cranium or represent overall body size changes. The results indicate that hybrid cranial and mandibular sizes, as well as limb length, exceed that of the parent taxa in all cases. All three F 1 hybrid crosses display similar patterns of size and form variation. These results are generally consistent with earlier studies on primates and other mammals, suggesting that the effects of hybridization may be similar across very different scenarios of hybridization, including different levels of hybrid fitness. This paper serves to supplement previous studies aimed at identifying F 1 hybrids in the fossil record and to introduce further research that will explore hybrid morphologies using mice as a proxy for better understanding hybridization in the hominin fossil record. Copyright © 2017 Elsevier Ltd. All rights reserved.

Course on hybrid calculation

International Nuclear Information System (INIS)

Weill, J.; Tellier; Bonnemay; Craigne; Chareton; Di Falco

1969-02-01

After a definition of hybrid calculation (combination of analogue and digital calculation) with a distinction between series and parallel hybrid computing, and a description of a hybrid computer structure and of task sharing between computers, this course proposes a description of hybrid hardware used in Saclay and Cadarache computing centres, and of operations performed by these systems. The next part addresses issues related to programming languages and software. The fourth part describes how a problem is organised for its processing on these computers. Methods of hybrid analysis are then addressed: resolution of optimisation problems, of partial differential equations, and of integral equations by means of different methods (gradient, maximum principle, characteristics, functional approximation, time slicing, Monte Carlo, Neumann iteration, Fischer iteration)

Hydraulic Hybrid Vehicles

Science.gov (United States)

EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

Research on a Household Dual Heat Source Heat Pump Water Heater with Preheater Based on ASPEN PLUS

Directory of Open Access Journals (Sweden)

Xiang Gou

2016-12-01

Full Text Available This article proposes a dual heat source heat pump bathroom unit with preheater which is feasible for a single family. The system effectively integrates the air source heat pump (ASHP and wastewater source heat pump (WSHP technologies, and incorporates a preheater to recover shower wastewater heat and thus improve the total coefficient of performance (COP of the system, and it has no electric auxiliary heating device, which is favorable to improve the security of the system operation. The process simulation software ASPEN PLUS, widely used in the design and optimization of thermodynamic systems, was used to simulate various cases of system use and to analyze the impact of the preheater on the system. The average COP value of a system with preheater is 6.588 and without preheater it is 4.677. Based on the optimization and analysis, under the standard conditions of air at 25 °C, relative humidity of 70%, wastewater at 35 °C, wastewater flow rate of 0.07 kg/s, tap water at 15 °C, and condenser outlet water temperature at 50 °C, the theoretical COP of the system can reach 9.784 at an evaporating temperature of 14.96 °C, condensing temperature of 48.74 °C, and preheated water temperature of 27.19 °C.

Mirror hybrid reactor optimization studies

International Nuclear Information System (INIS)

Bender, D.J.

1976-01-01

A system model of the mirror hybrid reactor has been developed. The major components of the model include (1) the reactor description, (2) a capital cost analysis, (3) various fuel management schemes, and (4) an economic analysis that includes the hybrid plus its associated fission burner reactors. The results presented describe the optimization of the mirror hybrid reactor, the objective being to minimize the cost of electricity from the hybrid fission-burner reactor complex. We have examined hybrid reactors with two types of blankets, one containing natural uranium, the other thorium. The major difference between the two optimized reactors is that the uranium hybrid is a significant net electrical power producer, whereas the thorium hybrid just about breaks even on electrical power. Our projected costs for fissile fuel production are approximately 50 $/g for 239 Pu and approximately 125 $/g for 233 U

Modeling solubility of CO2/hydrocarbon gas in ionic liquid ([emim][FAP]) using Aspen Plus simulations.

Science.gov (United States)

Bagchi, Bishwadeep; Sati, Sushmita; Shilapuram, Vidyasagar

2017-08-01

The Peng-Robinson equation of state with quadratic van der Waals (vdW) mixing rule model was chosen to perform the thermodynamic calculations in Flash3 column of Aspen Plus to predict the solubility of CO 2 or any one of the hydrocarbons (HCs) among methane, ethane, propane, and butane in an ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]). Bubble point pressure, solubility, bubble point temperature, fugacity, and partial molar volume at infinite dilution were obtained from the simulations, and enthalpy of absorption, Gibbs free energy of solvation, and entropy change of absorption were estimated by thermodynamic relations. Results show that carbon chain length has a significant effect on the bubble point pressure. Methane has the highest bubble point pressure among all the considered HCs and CO 2 . The bubble point pressure and fugacity variation with temperature is different for CO 2 as compared to HCs for mole fractions above 0.2. Two different profiles are noticed for enthalpy of absorption when plotted as a function of mole fraction of gas soluble in IL. Partial molar volume of CO 2 decreases with increase in temperature in [emim][FAP], while it is increased for HCs. Bubble point temperature decreases with increase in the mole fraction of the solute. Entropy of solvation increases with temperature till a particular value followed by a decrease with further increase in temperature. Gibbs free energy change of solvation showed that the process of solubility was spontaneous.

Comments On Clock Models In Hybrid Automata And Hybrid Control Systems

Directory of Open Access Journals (Sweden)

Virginia Ecaterina OLTEAN

2001-12-01

Full Text Available Hybrid systems have received a lot of attention in the past decade and a number of different models have been proposed in order to establish mathematical framework that is able to handle both continuous and discrete aspects. This contribution is focused on two models: hybrid automata and hybrid control systems with continuous-discrete interface and the importance of clock models is emphasized. Simple and relevant examples, some taken from the literature, accompany the presentation.

Hybrid Bloch brane

Energy Technology Data Exchange (ETDEWEB)

Bazeia, D.; Lima, Elisama E.M.; Losano, L. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)

2017-02-15

This work reports on models described by two real scalar fields coupled with gravity in the five-dimensional spacetime, with a warped geometry involving one infinite extra dimension. Through a mechanism that smoothly changes a thick brane into a hybrid brane, one investigates the appearance of hybrid branes hosting internal structure, characterized by the splitting on the energy density and the volcano potential, induced by the parameter which controls interactions between the two scalar fields. In particular, we investigate distinct symmetric and asymmetric hybrid brane scenarios. (orig.)

Effects of elevated concentrations of atmospheric CO{sub 2} and tropospheric O{sub 3} on leaf litter production and chemistry in trembling aspen and paper birch communities

Energy Technology Data Exchange (ETDEWEB)

Liu, L.; King, J.S. [Michigan Technological Univ., Houghton, MI (United States). School of Forest Resources and Environmental Science; Giardina, C.P. [United States Dept. of Agriculture Forest Service, Houghton, MI (United States)

2005-12-01

This study examined the effects of elevated carbon dioxide (CO{sub 2}) and elevated ozone (O{sub 3}) on the quantity and timing of nutrient release to plants and on soil carbon formation rates, and how they are influenced by the combined change in litter quality and quantity. The changes in leaf litter in response to environmental changes was characterized in order to understand the influence of global change on forests. Free-air CO{sub 2} enrichment (FACE) technology was used to examine leaf litter production and biochemical input to soil in response to elevated CO{sub 2} and O{sub 3} treatments. The study involved collecting litter from aspen and birch-aspen communities that had been exposed to FACE and O{sub 3} treatments for 6 years. The hypothesis of growth differentiation balance was used as the basis to develop other hypotheses regarding litter chemistry responses to elevated levels of carbon dioxide and ozone. It was assumed that environmental factors that increase the net balance of plant carbon sources relative to growth sinks will increase the allocation of photosynthate to the production of carbon-based secondary compounds. Litter was analyzed for concentrations of carbon, nitrogen, soluble sugars, lipids, lignin, cellulose, hemicellulose and carbon-based defensive compounds such as soluble phenolics and condensed tannins. The study showed that high levels of ozone greatly increased litter concentrations of soluble sugars, soluble phenolics and condensed tannins, but there were no major effects of elevated carbon dioxide or elevated ozone on the concentrations of individual carbon structural carbon hydrates such as cellulose, hemicellulose and lignin. It was concluded that in the future, the inputs of nitrogen, soluble sugars, condensed tannins, soluble phenolics, cellulose and lignin to forest soils can change as a result of small changes in litter chemistry resulting from elevated CO{sub 2}, tropospheric O{sub 3}, and changes in litter biomass

Gonad morphogenesis defects drive hybrid male sterility in asymmetric hybrid breakdown of Caenorhabditis nematodes.

Science.gov (United States)

Dey, Alivia; Jin, Qi; Chen, Yen-Chu; Cutter, Asher D

2014-01-01

Determining the causes and evolution of reproductive barriers to gene flow between populations, speciation, is the key to understanding the origin of diversity in nature. Many species manifest hybrid breakdown when they intercross, characterized by increasingly exacerbated problems in later generations of hybrids. Recently, Caenorhabditis nematodes have emerged as a genetic model for studying speciation, and here we investigate the nature and causes of hybrid breakdown between Caenorhabditis remanei and C. latens. We quantify partial F1 hybrid inviability and extensive F2 hybrid inviability; the ~75% F2 embryonic arrest occurs primarily during gastrulation or embryonic elongation. Moreover, F1 hybrid males exhibit Haldane's rule asymmetrically for both sterility and inviability, being strongest when C. remanei serves as maternal parent. We show that the mechanism by which sterile hybrid males are incapable of transferring sperm or a copulatory plug involves defective gonad morphogenesis, which we hypothesize results from linker cell defects in migration and/or cell death during development. This first documented case of partial hybrid male sterility in Caenorhabditis follows expectations of Darwin's corollary to Haldane's rule for asymmetric male fitness, providing a powerful foundation for molecular dissection of intrinsic reproductive barriers and divergence of genetic pathways controlling organ morphogenesis. © 2014 Wiley Periodicals, Inc.

New hybrid systems

International Nuclear Information System (INIS)

Bernardin, B.

2001-01-01

New hybrid systems are made up of a subcritical core, a spallation target and a proton accelerator. The neutrons that are produced in the target by the flux of protons are necessary to maintain the chain reaction of fission. Some parameters that are important for a classical nuclear reactor like doppler coefficient or delayed neutron fraction do not matter in a hybrid system. In a PWR-type reactor or in a fast reactor the concentration of actinides has a bad impact on these 2 parameters, so it is justified to study hybrid systems as actinide transmuters. The hybrid system, because of its external source of neutrons can put aside an important reactivity margin. This reactivity margin can be used to design safer nuclear reactors (particularly in some situations of reactivity accidents) or to irradiate fuel elements containing high concentrations of minor actinides that could not be allowed in a classical reactor. This article reviews various ways of integrating hybrid systems in a population of already existing nuclear reactors in order to manage quantities of plutonium, of minor actinides or of long-life fission products. (A.C.)

Epitaxial growth of hybrid nanostructures

Science.gov (United States)

Tan, Chaoliang; Chen, Junze; Wu, Xue-Jun; Zhang, Hua

2018-02-01

Hybrid nanostructures are a class of materials that are typically composed of two or more different components, in which each component has at least one dimension on the nanoscale. The rational design and controlled synthesis of hybrid nanostructures are of great importance in enabling the fine tuning of their properties and functions. Epitaxial growth is a promising approach to the controlled synthesis of hybrid nanostructures with desired structures, crystal phases, exposed facets and/or interfaces. This Review provides a critical summary of the state of the art in the field of epitaxial growth of hybrid nanostructures. We discuss the historical development, architectures and compositions, epitaxy methods, characterization techniques and advantages of epitaxial hybrid nanostructures. Finally, we provide insight into future research directions in this area, which include the epitaxial growth of hybrid nanostructures from a wider range of materials, the study of the underlying mechanism and determining the role of epitaxial growth in influencing the properties and application performance of hybrid nanostructures.

Hybrid laser-arc welding

DEFF Research Database (Denmark)

Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

Hybrid quantum information processing

Energy Technology Data Exchange (ETDEWEB)

Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo (Japan)

2014-12-04

I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

HYBRID VEHICLE CONTROL SYSTEM

Directory of Open Access Journals (Sweden)

V. Dvadnenko

2016-06-01

Full Text Available The hybrid vehicle control system includes a start–stop system for an internal combustion engine. The system works in a hybrid mode and normal vehicle operation. To simplify the start–stop system, there were user new possibilities of a hybrid car, which appeared after the conversion. Results of the circuit design of the proposed system of basic blocks are analyzed.

Techno-economic comparison of series hybrid, plug-in hybrid, fuel cell and regular cars

NARCIS (Netherlands)

van Vliet, O.P.R.|info:eu-repo/dai/nl/288519361; Kruithof, T.; Turkenburg, W.C.|info:eu-repo/dai/nl/073416355; Faaij, A.P.C.|info:eu-repo/dai/nl/10685903X

2010-01-01

We examine the competitiveness of series hybrid compared to fuel cell, parallel hybrid, and regular cars. We use public domain data to determine efficiency, fuel consumption, total costs of ownership and greenhouse gas emissions resulting from drivetrain choices. The series hybrid drivetrain can be

The Hybrid Advantage: Graduate Student Perspectives of Hybrid Education Courses

Science.gov (United States)

Hall, Sarah; Villareal, Donna

2015-01-01

Hybrid courses combine online and face-to-face learning environments. To organize and teach hybrid courses, instructors must understand the uses of multiple online learning tools and face-toface classroom activities to promote and monitor the progress of students. The purpose of this phenomenological study was to explore the perspectives of…

Optimal Design for Hybrid Ratio of Carbon/Basalt Hybrid Fiber Reinforced Resin Matrix Composites

Directory of Open Access Journals (Sweden)

XU Hong

2017-08-01

Full Text Available The optimum hybrid ratio range of carbon/basalt hybrid fiber reinforced resin composites was studied. Hybrid fiber composites with nine different hybrid ratios were prepared before tensile test.According to the structural features of plain weave, the unit cell's performance parameters were calculated. Finite element model was established by using SHELL181 in ANSYS. The simulated values of the sample stiffness in the model were approximately similar to the experimental ones. The stress nephogram shows that there is a critical hybrid ratio which divides the failure mechanism of HFRP into single failure state and multiple failure state. The tensile modulus, strength and limit tensile strain of HFRP with 45% resin are simulated by finite element method. The result shows that the tensile modulus of HFRP with 60% hybrid ratio increases by 93.4% compared with basalt fiber composites (BFRP, and the limit tensile strain increases by 11.3% compared with carbon fiber composites(CFRP.

Wood production potential in poplar plantations in Sweden

Energy Technology Data Exchange (ETDEWEB)

Christersson, Lars [Section of Short Rotation Forestry, VPE, SLU, Uppsala (Sweden)

2010-09-15

Shortage of oil, large variations in exports from Russia of wood to Europe, plenty of abandoned agriculture land, new ideas about a more intensive silviculture; these circumstances are driving forces in Sweden for planting fast-growing poplar and hybrid aspen clones on suitable land. The advantage of such trees is that the wood can be used for both energy (heat, biofuels, electricity), paper and for construction. Poplar clones bred in the USA and Belgium, and older hybrid aspen clones from Sweden, together with new poplar clones collected and selected for Swedish conditions from British Columbia, Canada, were planted during the 1990s in south and central Sweden. The stem diameters and heights of the trees have been measured during the last 10 years and the woody biomass production above ground has been calculated. MAI for all the plantations is 10-31 m{sup 3} or 3-10 ton DM per hectare with the highest annual woody production of 45 m{sup 3} or 15 ton DM per hectare in some years in a very dense plantation in the most southern part of Sweden. All the plantations have been fenced for at least the first ten years. The damage has been caused by stem canker, insects, leaf rust and by moose after removal of the fences. The possibilities for the use of poplar plantations as energy forest and vegetation filters are discussed. (author)

Hybridization in geese

NARCIS (Netherlands)

Ottenburghs, Jente; Hooft, van Pim; Wieren, van Sipke E.; Ydenberg, Ronald C.; Prins, Herbert H.T.

2016-01-01

The high incidence of hybridization in waterfowl (ducks, geese and swans) makes this bird group an excellent study system to answer questions related to the evolution and maintenance of species boundaries. However, knowledge on waterfowl hybridization is biased towards ducks, with a large

Hybrid Shipboard Microgrids

DEFF Research Database (Denmark)

Othman @ Marzuki, Muzaidi Bin; Anvari-Moghaddam, Amjad; Guerrero, Josep M.

2017-01-01

Strict regulation on emissions of air pollutants imposed by the maritime authorities has led to the introduction of hybrid microgrids to the shipboard power systems (SPSs) which acts toward energy efficient ships with less pollution. A hybrid energy system can include different means of generation...

ADVANCING PROTOCOLS FOR POPLARS in vitro PROPAGATION, REGENERATION AND SELECTION OF TRANSFORMANTS

Directory of Open Access Journals (Sweden)

Nataliia Kutsokon

2013-02-01

Full Text Available Poplars (genus Populus have emerged as a model organism for forest biotechnology, and genetic modification is more advanced for this genus than for any other tree. So far several protocols for microclonal propagation and regeneration for Populus species have been developed. However it is well known that these protocols differ for various species and need to be adapted even for different clones of the same species. This work was focused on developing of protocols for propagation, regeneration and putative transformant´s selection of aspen Populus tremula L. and other two fast-growing Populus species (P. nigra L., P. x canadensis Moench. The regeneration ability for black poplar explants was demonstrated to be three times higher compared to those for aspen and hybrid poplar. It was found that concentration 1 mg/L of phosphinothricin and 25 mg/L of kanamycin is toxic for non- transgenic plant tissues of P. x canadensis and can be applied in transformation experiments when genes of resistance to the corresponding selective agents into the plant genome are introduced.

Effect of sample storage time on detection of hybridization signals in Checkerboard DNA-DNA hybridization.

Science.gov (United States)

do Nascimento, Cássio; Muller, Katia; Sato, Sandra; Albuquerque Junior, Rubens Ferreira

2012-04-01

Long-term sample storage can affect the intensity of the hybridization signals provided by molecular diagnostic methods that use chemiluminescent detection. The aim of this study was to evaluate the effect of different storage times on the hybridization signals of 13 bacterial species detected by the Checkerboard DNA-DNA hybridization method using whole-genomic DNA probes. Ninety-six subgingival biofilm samples were collected from 36 healthy subjects, and the intensity of hybridization signals was evaluated at 4 different time periods: (1) immediately after collecting (n = 24) and (2) after storage at -20 °C for 6 months (n = 24), (3) for 12 months (n = 24), and (4) for 24 months (n = 24). The intensity of hybridization signals obtained from groups 1 and 2 were significantly higher than in the other groups (p  0.05). The Checkerboard DNA-DNA hybridization method was suitable to detect hybridization signals from all groups evaluated, and the intensity of signals decreased significantly after long periods of sample storage.

Hybrid radiator cooling system

Science.gov (United States)

France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

2016-03-15

A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

Hybrid quantum computation

International Nuclear Information System (INIS)

Sehrawat, Arun; Englert, Berthold-Georg; Zemann, Daniel

2011-01-01

We present a hybrid model of the unitary-evolution-based quantum computation model and the measurement-based quantum computation model. In the hybrid model, part of a quantum circuit is simulated by unitary evolution and the rest by measurements on star graph states, thereby combining the advantages of the two standard quantum computation models. In the hybrid model, a complicated unitary gate under simulation is decomposed in terms of a sequence of single-qubit operations, the controlled-z gates, and multiqubit rotations around the z axis. Every single-qubit and the controlled-z gate are realized by a respective unitary evolution, and every multiqubit rotation is executed by a single measurement on a required star graph state. The classical information processing in our model requires only an information flow vector and propagation matrices. We provide the implementation of multicontrol gates in the hybrid model. They are very useful for implementing Grover's search algorithm, which is studied as an illustrative example.

Security in hybrid cloud computing

OpenAIRE

Koudelka, Ondřej

2016-01-01

This bachelor thesis deals with the area of hybrid cloud computing, specifically with its security. The major aim of the thesis is to analyze and compare the chosen hybrid cloud providers. For the minor aim this thesis compares the security challenges of hybrid cloud as opponent to other deployment models. In order to accomplish said aims, this thesis defines the terms cloud computing and hybrid cloud computing in its theoretical part. Furthermore the security challenges for cloud computing a...

Hybrid intermediaries

OpenAIRE

Cetorelli, Nicola

2014-01-01

I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

Hybrid Ventilation Air Flow Process

DEFF Research Database (Denmark)

Heiselberg, Per Kvols

The scope of this annex is therefore to obtain better knowledge of the use of hybrid ventilation technologies. The annex focus on development of control strategies for hybrid ventilation, on development of methods to predict hybrid ventilation performance in office buildings and on implementation...

Compositional Modelling of Stochastic Hybrid Systems

NARCIS (Netherlands)

Strubbe, S.N.

2005-01-01

In this thesis we present a modelling framework for compositional modelling of stochastic hybrid systems. Hybrid systems consist of a combination of continuous and discrete dynamics. The state space of a hybrid system is hybrid in the sense that it consists of a continuous component and a discrete

Genomic Prediction of Barley Hybrid Performance

Directory of Open Access Journals (Sweden)

Norman Philipp

2016-07-01

Full Text Available Hybrid breeding in barley ( L. offers great opportunities to accelerate the rate of genetic improvement and to boost yield stability. A crucial requirement consists of the efficient selection of superior hybrid combinations. We used comprehensive phenotypic and genomic data from a commercial breeding program with the goal of examining the potential to predict the hybrid performances. The phenotypic data were comprised of replicated grain yield trials for 385 two-way and 408 three-way hybrids evaluated in up to 47 environments. The parental lines were genotyped using a 3k single nucleotide polymorphism (SNP array based on an Illumina Infinium assay. We implemented ridge regression best linear unbiased prediction modeling for additive and dominance effects and evaluated the prediction ability using five-fold cross validations. The prediction ability of hybrid performances based on general combining ability (GCA effects was moderate, amounting to 0.56 and 0.48 for two- and three-way hybrids, respectively. The potential of GCA-based hybrid prediction requires that both parental components have been evaluated in a hybrid background. This is not necessary for genomic prediction for which we also observed moderate cross-validated prediction abilities of 0.51 and 0.58 for two- and three-way hybrids, respectively. This exemplifies the potential of genomic prediction in hybrid barley. Interestingly, prediction ability using the two-way hybrids as training population and the three-way hybrids as test population or vice versa was low, presumably, because of the different genetic makeup of the parental source populations. Consequently, further research is needed to optimize genomic prediction approaches combining different source populations in barley.

Nanoscale Organic Hybrid Electrolytes

KAUST Repository

Nugent, Jennifer L.

2010-08-20

Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale Organic Hybrid Electrolytes

KAUST Repository

Nugent, Jennifer L.; Moganty, Surya S.; Archer, Lynden A.

2010-01-01

Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimal control of hybrid vehicles

CERN Document Server

Jager, Bram; Kessels, John

2013-01-01

Optimal Control of Hybrid Vehicles provides a description of power train control for hybrid vehicles. The background, environmental motivation and control challenges associated with hybrid vehicles are introduced. The text includes mathematical models for all relevant components in the hybrid power train. The power split problem in hybrid power trains is formally described and several numerical solutions detailed, including dynamic programming and a novel solution for state-constrained optimal control problems based on Pontryagin’s maximum principle.   Real-time-implementable strategies that can approximate the optimal solution closely are dealt with in depth. Several approaches are discussed and compared, including a state-of-the-art strategy which is adaptive for vehicle conditions like velocity and mass. Two case studies are included in the book: ·        a control strategy for a micro-hybrid power train; and ·        experimental results obtained with a real-time strategy implemented in...

Hybrid solar lighting distribution systems and components

Science.gov (United States)

Muhs, Jeffrey D [Lenoir City, TN; Earl, Dennis D [Knoxville, TN; Beshears, David L [Knoxville, TN; Maxey, Lonnie C [Powell, TN; Jordan, John K [Oak Ridge, TN; Lind, Randall F [Lenoir City, TN

2011-07-05

A hybrid solar lighting distribution system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates all components.

PV-hybrid and mini-grid

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

Within the 5th European PV-hybrid and mini-grid conference 29th and 30th April, 2010 in Tarragona (Spain) the following lectures were held: (1) Overview of IEA PVPS Task 11 PV-hybrid systems within mini grids; (2) Photovoltaic revolution for deployment in developing countries; (3) Legal and financial conditions for the sustainable operation of mini-grids; (4) EU instruments to promote renewable energies in developing countries; (5) PV hybridization of diesel electricity generators: Conditions of profitability and examples in differential power and storage size ranges; (6) Education suit of designing PV hybrid systems; (7) Sustainable renewable energy projects for intelligent rural electrification in Laos, Cambodia and Vietnam; (8) Techno-economic feasibility of energy supply of remote villages in Palestine by PV systems, diesel generators and electric grid (Case studies: Emnazeil and Atouf villages); (9) Technical, economical and sustainability considerations of a solar PV mini grid as a tool for rural electrification in Uganda; (10) Can we rate inverters for rural electrification on the basis of energy efficiency?; (11) Test procedures for MPPT charge controllers characterization; (12) Energy storage for mini-grid stabilization; (13) Redox flow batteries - Already an alternative storage solution for hybrid PV mini-grids?; (14) Control methods for PV hybrid mini-grids; (15) Partial AC-coupling in mini-grids; (15) Normative issues of small wind turbines in PV hybrid systems; (16) Communication solutions for PV hybrid systems; (17) Towards flexible control and communication of mini-grids; (18) PV/methanol fuel cell hybrid system for powering a highway security variable message board; (19) Polygeneration smartgrids: A solution for the supply of electricity, potable water and hydrogen as fuel for transportation in remote Areas; (20) Implementation of the Bronsbergen micro grid using FACDS; (21) A revisited approach for the design of PV wind hybrid systems; (22

Plug-In Hybrid Electric Vehicle Basics | NREL

Science.gov (United States)

Plug-In Hybrid Electric Vehicle Basics Plug-In Hybrid Electric Vehicle Basics Imagine being able to one that's in a standard hybrid electric vehicle. The larger battery pack allows plug-in hybrids to between fill-ups) that's very similar to the range of a conventional vehicle. A plug-in hybrid vehicle's

Hybridization and management of oak populations

Science.gov (United States)

Oliver Gailing

2017-01-01

Hybridization can result in the transfer of adaptations among species and may contribute to speciation processes. On the other hand, hybridization can also result in a loss of species diversity due to asymmetric gene flow between species (genetic swamping) and in low hybrid fitness. An understanding of the outcomes of interspecific hybridization is crucial for the...

Hydrothermal stability of silica, hybrid silica and Zr-doped hybrid silica membranes

NARCIS (Netherlands)

ten Hove, Marcel; Luiten-Olieman, Mieke W.J.; Huiskes, Cindy; Nijmeijer, Arian; Winnubst, Louis

2017-01-01

Hybrid silica membranes have demonstrated to possess a remarkable hydrothermal stability in pervaporation and gas separation processes allowing them to be used in industrial applications. In several publications the hydrothermal stability of pure silica or that of hybrid silica membranes are

Editorial: Hybrid Systems

DEFF Research Database (Denmark)

Olderog, Ernst-Rüdiger; Ravn, Anders Peter

2007-01-01

An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005.......An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005....

The situation of hybrid vehicles in Japan; Le point sur les vehicules hybrides au Japon

Energy Technology Data Exchange (ETDEWEB)

Perran, Th.

2000-01-01

Among the different competitors of the race on hybrid vehicles development, Honda was the fastest with its Insight model presented in November 1, 1999. This mass production hybrid vehicle can reach performances of 35 km/l. This new record could be obtained thanks to the development of more efficient weak mixture internal combustion engines and to the lightening of vehicles thanks to the massive use of aluminium. Today, each Japanese car manufacturer has his own hybrid vehicle prototype and one can expect a wave of performing hybrid vehicles on the automotive market in 2001. Toyota remains at the top with its second model, the future 6 places HV-M4 model which will be the very first four wheel drive mono-space hybrid vehicle. (J.S.)

Russia and hybrid warfare: identifying critical elements in successful applications of hybrid tactics

OpenAIRE

Neville, Seth B.

2015-01-01

Approved for public release; distribution is unlimited With the Russian annexation of Crimea in 2014, hybrid war became a buzzword within political and academic circles. This thesis examines hybrid warfare applications using contemporary and historical examples. The analysis seeks to determine why a country was or was not successful in its execution of hybrid war, and it assesses the geo-political context of cost, benefit, and risk for an aggressor state contributing to its decision to eng...

Genetic incompatibility dampens hybrid fertility more than hybrid viability: yeast as a case study.

Directory of Open Access Journals (Sweden)

Meibo Xu

Full Text Available Genetic incompatibility is believed to be the major cause of postzygotic reproductive isolation. Despite huge efforts seeking for speciation-related incompatibilities in the past several decades, a general understanding of how genetic incompatibility evolves in affecting hybrid fitness is not available, primarily due to the fact that the number of known incompatibilities is small. Instead of further mapping specific incompatible genes, in this paper we aimed to know the overall effects of incompatibility on fertility and viability, the two aspects of fitness, by examining 89 gametes produced by yeast S. cerevisiae-S. paradoxus F1 hybrids. Homozygous F2 hybrids formed by autodiploidization of F1 gametes were subject to tests for growth rate and sporulation efficiency. We observed much stronger defects in sporulation than in clonal growth for every single F2 hybrid strain, indicating that genetic incompatibility affects hybrid fertility more than hybrid viability in yeast. We related this finding in part to the fast-evolving nature of meiosis-related genes, and proposed that the generally low expression levels of these genes might be a cause of the observation.

Low CO2-emissions hybrid solar combined-cycle power system with methane membrane reforming

International Nuclear Information System (INIS)

Li, Yuanyuan; Zhang, Na; Cai, Ruixian

2013-01-01

Based on the principle of cascade utilization of multiple energy resources, a gas-steam combined cycle power system integrated with solar thermo-chemical fuel conversion and CO 2 capture has been proposed and analyzed. The collected solar heat at 550 °C drives the endothermic methane reforming and is converted to the produced syngas chemical exergy, and then released as high-temperature thermal energy via combustion for power generation, achieving its high-efficiency heat-power conversion. The reforming reaction is integrated with a hydrogen separation membrane, which continuously withdraws hydrogen from the reaction zone and enables nearly full methane conversion. The CO 2 enriched gas being concentrated in the retentate zone is collected and processed with pre-combustion decarbonization. The system is thermodynamically simulated using the ASPEN PLUS code. The results show that with 91% CO 2 captured, the specific CO 2 emission is 25 g/kWh. An exergy efficiency of 58% and thermal efficiency of 51.6% can be obtained. A fossil fuel saving ratio of 31.2% is achievable with a solar thermal share of 28.2%, and the net solar-to-electricity efficiency based on the gross solar heat incident on the collector is about 36.4% compared with the same gas-steam combined cycle system with an equal CO 2 removal ratio obtained by post-combustion decarbonization. - Highlights: ► A solar-assisted hybrid combined cycle power system has been proposed and analyzed. ► The system integrates power generation with solar-driven reforming and CO 2 capture. ► solar heat upgrading and high-efficiency heat-to-power conversion are achieved. ► membrane reforming enables high CH 4 conversion and pre-combustion CO 2 capture. ► The system thermodynamic performances have been investigated and compared

Proceedings of the 2015 A.S.P.E.N. Research Workshop - Taste Signaling: Impact on Food Selection, Intake, and Health

Science.gov (United States)

Spector, Alan C.; le Roux, Carel W; Munger, Steven D.; Travers, Susan P.; Sclafani, Anthony; Mennella, Julie A.

2016-01-01

This paper summarizes research findings from six experts in the field of taste and feeding that were presented at the 2015 ASPEN Research Workshop. The theme was focused on the interaction of taste signals with those of a postingestive origin and how this contributes to regulation of food intake through both physiological and learning processes. Gastric bypass results in exceptional loss of fat mass, increases in circulating levels of key gut peptides, some of which are also expressed along with their cognate receptors in taste buds. Changes in taste preference and food selection in both bariatric surgery patients and rodent models have been reported. Accordingly, the effects of this surgery on taste-related behavior were examined. The conservation of receptor and peptide signaling mechanisms in gustatory and extraoral tissues was discussed in the context of taste responsiveness and the regulation of metabolism. New findings detailing the features of neural circuits between the caudal nucleus of the solitary tract (NST), receiving visceral input from the vagus nerve, and the rostral NST, receiving taste input, were discussed, as was how early life experience with taste stimuli and learned associations between flavor and postoral consequences of nutrients can exert potent and long-lasting effects on feeding PMID:26598504

Mirror fusion--fission hybrids

International Nuclear Information System (INIS)

Lee, J.D.

1978-01-01

The fusion-fission concept and the mirror fusion-fission hybrid program are outlined. Magnetic mirror fusion drivers and blankets for hybrid reactors are discussed. Results of system analyses are presented and a reference design is described

Triplex in-situ hybridization

Science.gov (United States)

Fresco, Jacques R.; Johnson, Marion D.

2002-01-01

Disclosed are methods for detecting in situ the presence of a target sequence in a substantially double-stranded nucleic acid segment, which comprises: a) contacting in situ under conditions suitable for hybridization a substantially double-stranded nucleic acid segment with a detectable third strand, said third strand being capable of hybridizing to at least a portion of the target sequence to form a triple-stranded structure, if said target sequence is present; and b) detecting whether hybridization between the third strand and the target sequence has occured.

Hybrid electric vehicles TOPTEC

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-06-21

This one-day TOPTEC session began with an overview of hybrid electric vehicle technology. Updates were given on alternative types of energy storage, APU control for low emissions, simulation programs, and industry and government activities. The keynote speech was about battery technology, a key element to the success of hybrids. The TOPEC concluded with a panel discussion on the mission of hybrid electric vehicles, with a perspective from industry and government experts from United States and Canada on their view of the role of this technology.

Simulation of the SSC [Superconducting Super Collider] refrigeration system using the ASPEN/SP process simulator

International Nuclear Information System (INIS)

Rasson, J.; Dweck, J.

1990-08-01

The SSC Magnet must maintain at a super conducting temperature of 4 K. The proposed refrigeration cooling processes consist of fairly simple closed cycles which take advantage of the Joule-Thompson effect via a series of expansions and compressions of helium gas which has been precooled by liquid nitrogen. The processes currently under consideration consist of three cycles, the 20 K shield cooling, the 45 K helium refrigerator and the helium liquefier. The process units which are to be employed are compressors, turbines, expanders, mixers, flashes, two stream heat exchangers and multiple stream heat exchangers. The cycles are to be operated at or near steady state. Due to the large number of competing cooling sector designs to be considered and the high capital and operating costs of the proposed processes, the SSC Laboratory requires a software tool for the validation and optimization of the individual designs and for the performance of cost-benefit analyses among competing designs. Since these processes are steady state flow processes involving primarily standard unit operations, a decision was made to investigate the application of a commercial process simulator to the task. Several months of internal evaluations by the SSC Laboratory revealed that while the overall structure and calculation approach of number of the commercial simulators were appropriate for this task, all were lacking essential capabilities in the areas of thermodynamic property calculations for cryogenic systems and modeling of complex, multiple stream heat exchangers. An acceptable thermodynamics model was provided and a series of simple, but representative benchmark problems developed. The model and problems were provided to three software vendors. Based on the results of the benchmark test, the ASPEN/SP process simulator was selected for future modeling work

Hydraulic Hybrid Vehicle Publications | Transportation Research | NREL

Science.gov (United States)

Hydraulic Hybrid Vehicle Publications Hydraulic Hybrid Vehicle Publications The following technical papers and fact sheets provide information about NREL's hydraulic hybrid fleet vehicle evaluations . Refuse Trucks Project Startup: Evaluating the Performance of Hydraulic Hybrid Refuse Vehicles. Bob

Overview of hybrid electric vehicle trend

Science.gov (United States)

Wang, Haomiao; Yang, Weidong; Chen, Yingshu; Wang, Yun

2018-04-01

With the increase of per capita energy consumption, environmental pollution is worsening. Using new alternative sources of energy, reducing the use of conventional fuel-powered engines is imperative. Due to the short period, pure electric vehicles cannot be mass-produced and there are many problems such as imperfect charging facilities. Therefore, the development of hybrid electric vehicles is particularly important in a certain period. In this paper, the classification of hybrid vehicle, research status of hybrid vehicle and future development trends of hybrid vehicles is introduced. It is conducive to the public understanding of hybrid electric vehicles, which has a certain theoretical significance.

77 FR 25490 - Changes in Flood Hazard Determinations

Science.gov (United States)

2012-04-30

... Department, 1905 m/index.php/ Gulf Shores, P.O. West 1st Street, alabama/baldwin/. Box 299, Gulf Gulf Shores..., Management m/index.php/ 211 West Aspen Section, 211 West arizona/coconino- Avenue, Flagstaff, Aspen Avenue..., Management m/index.php/ 211 West Aspen Section, 211 West arizona/coconino- Avenue, Flagstaff, Aspen Avenue...

Laser driven fusion fission hybrids

International Nuclear Information System (INIS)

Hansen, L.F.; Maniscalco, J.A.

1977-11-01

The role of the fusion-fission hybrid reactor (FFHR) as a fissile fuel and/or power producer is discussed. As long range options to supply the world energy needs, hybrid-fueled thermal-burner reactors are compared to liquid metal fast breeder reactors (LMFBR). A discussion of different fuel cycles (thorium, depleted uranium, and spent fuel) is presented in order to compare the energy multiplication, the production of fissile fuel, the laser efficiency and pellet gain requirements of the hybrid reactor. Lawrence Livermore Laboratory (LLL) has collaborated with Bechtel Corporation and with Westinghouse in two engineering design studies of laser fusion driven hybrid power plants. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering operational parameters, such as energy multiplication, power density, burn-up and plutonium production as a function time

Genomic and transcriptomic alterations following intergeneric hybridization and polyploidization in the Chrysanthemum nankingense×Tanacetum vulgare hybrid and allopolyploid (Asteraceae).

Science.gov (United States)

Qi, Xiangyu; Wang, Haibin; Song, Aiping; Jiang, Jiafu; Chen, Sumei; Chen, Fadi

2018-01-01

Allopolyploid formation involves two major events: interspecific hybridization and polyploidization. A number of species in the Asteraceae family are polyploids because of frequent hybridization. The effects of hybridization on genomics and transcriptomics in Chrysanthemum nankingense×Tanacetum vulgare hybrids have been reported. In this study, we obtained allopolyploids by applying a colchicine treatment to a synthesized C. nankingense × T. vulgare hybrid. Sequence-related amplified polymorphism (SRAP), methylation-sensitive amplification polymorphism (MSAP), and high-throughput RNA sequencing (RNA-Seq) technologies were used to investigate the genomic, epigenetic, and transcriptomic alterations in both the hybrid and allopolyploids. The genomic alterations in the hybrid and allopolyploids mainly involved the loss of parental fragments and the gain of novel fragments. The DNA methylation level of the hybrid was reduced by hybridization but was restored somewhat after polyploidization. There were more significant differences in gene expression between the hybrid/allopolyploid and the paternal parent than between the hybrid/allopolyploid and the maternal parent. Most differentially expressed genes (DEGs) showed down-regulation in the hybrid/allopolyploid relative to the parents. Among the non-additive genes, transgressive patterns appeared to be dominant, especially repression patterns. Maternal expression dominance was observed specifically for down-regulated genes. Many methylase and methyltransferase genes showed differential expression between the hybrid and parents and between the allopolyploid and parents. Our data indicate that hybridization may be a major factor affecting genomic and transcriptomic changes in newly formed allopolyploids. The formation of allopolyploids may not simply be the sum of hybridization and polyploidization changes but also may be influenced by the interaction between these processes.

Systems for hybrid cars

Science.gov (United States)

Bitsche, Otmar; Gutmann, Guenter

Not only sharp competition but also legislation are pushing development of hybrid drive trains. Based on conventional internal combustion engine (ICE) vehicles, these drive trains offer a wide range of benefits from reduced fuel consumption and emission to multifaceted performance improvements. Hybrid electric drive trains may also facilitate the introduction of fuel cells (FC). The battery is the key component for all hybrid drive trains, as it dominates cost and performance issues. The selection of the right battery technology for the specific automotive application is an important task with an impact on costs of development and use. Safety, power, and high cycle life are a must for all hybrid applications. The greatest pressure to reduce cost is in soft hybrids, where lead-acid embedded in a considerate management presents the cheapest solution, with a considerable improvement in performance needed. From mild to full hybridization, an improvement in specific power makes higher costs more acceptable, provided that the battery's service life is equivalent to the vehicle's lifetime. Today, this is proven for the nickel-metal hydride system. Lithium ion batteries, which make use of a multiple safety concept, and with some development anticipated, provide even better prospects in terms of performance and costs. Also, their scalability permits their application in battery electric vehicles—the basis for better performance and enhanced user acceptance. Development targets for the batteries are discussed with a focus on system aspects such as electrical and thermal management and safety.

Hybrid Management in Hospitals

DEFF Research Database (Denmark)

Byrkjeflot, Haldor; Jespersen, Peter Kragh

2010-01-01

Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer......Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer...

Completeness in Hybrid Type Theory

DEFF Research Database (Denmark)

Areces, Carlos; Blackburn, Patrick Rowan; Huertas, Antonia

2014-01-01

We show that basic hybridization (adding nominals and @ operators) makes it possible to give straightforward Henkin-style completeness proofs even when the modal logic being hybridized is higher-order. The key ideas are to add nominals as expressions of type t, and to extend to arbitrary types th......-style intensional models; we build, as simply as we can, hybrid logicover Henkin’s logic...

A battery-fuel cell hybrid auxiliary power unit for trucks: Analysis of direct and indirect hybrid configurations

International Nuclear Information System (INIS)

Samsun, Remzi Can; Krupp, Carsten; Baltzer, Sidney; Gnörich, Bruno; Peters, Ralf; Stolten, Detlef

2016-01-01

Highlights: • A battery-fuel cell hybrid auxiliary power unit for heavy duty vehicles is reported. • Comparison of direct and indirect hybrids using representative load profiles. • Evaluation based on validated fuel cell system and battery models. • Indirect hybrid with constant fuel cell load yields 29.3% hybrid system efficiency. • Fuel cell should be pre-heated using waste heat from the diesel engine during drive. - Abstract: The idling operation of engines in heavy duty vehicles to cover electricity demand during layovers entails significant fuel consumption and corresponding emissions. Indeed, this mode of operation is highly inefficient and a noteworthy contributor to the transportation sector’s aggregate carbon dioxide emissions. Here, a potential solution to this wasteful practice is outlined in the form of a hybrid battery-fuel cell system for application as an auxiliary power unit for trucks. Drawing on experimentally-validated fuel cell and battery models, several possible hybrid concepts are evaluated and direct and indirect hybrid configurations analyzed using a representative load profile. The results indicate that a direct hybrid configuration is only applicable if the load demand profile does not deviate strongly from the assumed profile. Operation of an indirect hybrid with a constant fuel cell load yields the greatest hybrid system efficiency, at 29.3%, while battery size could be reduced by 87% if the fuel cell is operated at the highest dynamics. Maximum efficiency in truck applications can be achieved by pre-heating the system prior to operation using exhaust heat from the motor, which increased system efficiency from 25.3% to 28.1%, including start-up. These findings confirm that hybrid systems could offer enormous fuel savings and constitute a sizeable step on the path toward energy-efficient and environmentally-friendly heavy duty vehicles that does not necessitate a fuel switch.

Hybrid systems with constraints

CERN Document Server

Daafouz, Jamal; Sigalotti, Mario

2013-01-01

Control theory is the main subject of this title, in particular analysis and control design for hybrid dynamic systems.The notion of hybrid systems offers a strong theoretical and unified framework to cope with the modeling, analysis and control design of systems where both continuous and discrete dynamics interact. The theory of hybrid systems has been the subject of intensive research over the last decade and a large number of diverse and challenging problems have been investigated. Nevertheless, many important mathematical problems remain open.This book is dedicated mainly to

Relative biocompatibility of micro-hybrid and nano-hybrid light-activated composite resins.

Science.gov (United States)

Olabisi Arigbede, Abiodun; Folasade Adeyemi, Bukola; Femi-Akinlosotu, Omowumi

2017-01-01

Background. In vitro studies have revealed a direct association between resin content and cytotoxicity of composite resins; however, implantation studies in this regard are sparse. This study investigates the relationship between filler content of composite resins and biocompatibility. Methods. This research employed twelve 180‒200-gr male Wistar rats, 1 nano-hybrid (Prime-Dent Inc.) and 1 micro-hybrid (Medental Inc.) composite resins containing 74% and 80‒90% filler content, respectively. The samples were assessed on the 2nd, 14th and 90th day of implantation. Four rats were allocated to each day in this experimental study. A section of 1.5mm long cured nano-hybrid and micro-hybrid materials were implanted into the right and left upper and lower limbs of the rats, respectively. Eight samples were generated on each day of observation. Inflammation was graded according to the criteria suggested by Orstavik and Major. Pearson's chi-squared test was employed to determine the relationship between the tissue responses of the two materials. Statistical significance was set at P resin had a score of 3.0 for cellular inflammation. On the 14th day, the micro-hybrid resin also exhibited a lower average grade for cellular inflammation. On the 90th day, the micro-hybrid resin had a higher grade of inflammation (0.9) compared to 0.3 recorded for nano-hybrid. The composite resins with higher filler content elicited a significantly lower grade of inflammation irrespective of the duration (χ=20.000, df=8, P=0.010) while the composite resins with lower filler content elicited a significantly lower inflammatory response on the 90th day (χ=4.000, df=1, P=0.046). Conclusion. The composite resins with higher filler content generally elicited significantly lower grades of inflammation, and the composite resins with lower filler content exhibited significantly lower inflammatory response on the 90th day of implantation.

Estimation of power production potential from natural gas pressure reduction stations in pakistan using aspen hysys

International Nuclear Information System (INIS)

Unar, I.N.; Aftab, A.

2015-01-01

Pakistan is a gas rich but power poor country. It consumes approximately 1, 559 Billion cubic feet of natural gas annually. Gas is transported around the country in a system of pressurized transmission pipelines under a pressure-range of 600-1 000 psig exclusively operated by two state owned companies i.e. SNGPL (Sui Northern Gas Pipelines Limited) and SSGCL (Sui Southern Gas Company Limited). The gas is distributed by reducing from the transmission pressure into distribution pressure up to maximum level of 150 psig at the city gate stations normally called SMS (Sales Metering Station). As a normal practice gas pressure reduction at those SMSs is accomplished in pressure regulators (PCVs or in of natural gas is an untapped energy resource which is currently wasted by its throttling. This pressure reduction at SMS (pressure drop through SMS) may also be achieved by expansion of natural gas in TE, which converts its pressure into the mechanical energy, which can be transmitted any loading device for example electric generator. The aim of present paper is to explore the expected power production potential of various Sales Metering Stations of SSGCL company in Pakistan. The model of sales metering station was developed in a standard flow sheeting software Aspen HYSYS at the rate 7.1 to calculate power and study other parameters when an expansion turbine is used instead of throttling valves. It was observed from the simulation results that a significant power (more than 140 KW) can be produced at pressure reducing stations of SSGC network with gas flows more than 2.2 MMSCFD and pressure ration more than 1.3. (author)

Hybrid Electric Vehicle Testing | Transportation Research | NREL

Science.gov (United States)

Hybrid Electric Vehicle Evaluations Hybrid Electric Vehicle Evaluations How Hybrid Electric Vehicles Work Hybrid electric vehicles combine a primary power source, an energy storage system, and an is used to propel the vehicle during normal drive cycles. The batteries supply additional power for

Hybrid Electric Vehicle Publications | Transportation Research | NREL

Science.gov (United States)

Hybrid Electric Vehicle Publications Hybrid Electric Vehicle Publications The following technical papers, conference papers, and fact sheets provide information about NREL's hybrid electric fleet vehicle Class 8 Hybrid Electric Delivery Trucks. Mike Lammert. (2011) FedEx Delivery Trucks In-Use and Vehicle

Alternative Fuels Data Center: Hybrid Electric Vehicles

Science.gov (United States)

. A wide variety of hybrid electric vehicle models is currently available. Although HEVs are often -go traffic), further improving fuel economy. Mild hybrid systems cannot power the vehicle using Hybrid Electric Vehicles to someone by E-mail Share Alternative Fuels Data Center: Hybrid Electric

Effects of natural hybrid and non-hybrid Epichloë endophytes on the response of Hordelymus europaeus to drought stress.

Science.gov (United States)

Oberhofer, Martina; Güsewell, Sabine; Leuchtmann, Adrian

2014-01-01

Interspecific hybrid endophytes of the genus Epichloë (Ascomycota, Clavicipitaceae) are prevalent in wild grass populations, possibly because of their larger gene variation, resulting in increased fitness benefits for host plants; however, the reasons are not yet known. We tested hypotheses regarding niche expansion mediated by hybrid endophytes, population-dependent interactions and local co-adaptation in the woodland grass Hordelymus europaeus, which naturally hosts both hybrid and non-hybrid endophyte taxa. Seedlings derived from seeds of four grass populations made endophyte free were re-inoculated with hybrid or non-hybrid endophyte strains, or left endophyte free. Plants were grown in the glasshouse with or without drought treatment. Endophyte infection increased plant biomass and tiller production by 10-15% in both treatments. Endophyte types had similar effects on growth, but opposite effects on reproduction: non-hybrid endophytes increased seed production, whereas hybrid endophytes reduced or prevented it completely. The results are consistent with the observation that non-hybrid endophytes in H. europaeus prevail at dry sites, but cannot explain the prevalence of hybrid endophytes. Thus, our results do not support the hypothesis of niche expansion of hybrid-infected plants. Moreover, plants inoculated with native relative to foreign endophytes yielded higher infections, but both showed similar growth and survival, suggesting weak co-adaptation. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Mechanical and thermal design of hybrid blankets

International Nuclear Information System (INIS)

Schultz, K.R.

1978-01-01

The thermal and mechanical aspects of hybrid reactor blanket design considerations are discussed. This paper is intended as a companion to that of J. D. Lee of Lawrence Livermore Laboratory on the nuclear aspects of hybrid reactor blanket design. The major design characteristics of hybrid reactor blankets are discussed with emphasis on the areas of difference between hybrid reactors and standard fusion or fission reactors. Specific examples are used to illustrate the design tradeoffs and choices that must be made in hybrid reactor design. These examples are drawn from the work on the Mirror Hybrid Reactor

Deriving simulators for hybrid Chi models

NARCIS (Netherlands)

Beek, van D.A.; Man, K.L.; Reniers, M.A.; Rooda, J.E.; Schiffelers, R.R.H.

2006-01-01

The hybrid Chi language is formalism for modeling, simulation and verification of hybrid systems. The formal semantics of hybrid Chi allows the definition of provably correct implementations for simulation, verification and realtime control. This paper discusses the principles of deriving an

Hybrid Universities in Malaysia

Science.gov (United States)

Lee, Molly; Wan, Chang Da; Sirat, Morshidi

2017-01-01

Are Asian universities different from those in Western countries? Premised on the hypothesis that Asian universities are different because of hybridization between Western academic models and local traditional cultures, this paper investigates the hybrid characteristics in Malaysian universities resulting from interaction between contemporary…

Characterization of Metabolic Pathways and Absorption of Sea Cucumber Saponins, Holothurin A and Echinoside A, in Vitro and in Vivo.

Science.gov (United States)

Song, Shanshan; Zhang, Lingyu; Cao, Jian; Xiang, Gao; Cong, Peixu; Dong, Ping; Li, Zhaojie; Xue, Changhu; Xue, Yong; Wang, Yuming

2017-08-01

Sea cucumber saponins (SCSs) exhibit a wide spectrum of bioactivities, but their metabolic characteristics are not well elucidated. In this study, the metabolism of holothurin A (HA) and echinoside A (EA), 2 major saponins in sea cucumber, by gut microflora were investigated. First, we conducted an in vitro study, where in the SCSs were incubated with intestinal microflora and the metabolites were detected by high pressure liquid chromatography-high resolution mass spectrometry. We also conducted an in vivo study on rats, where in the intestinal contents, serum, urine, and feces were collected and evaluated after oral administration of SCSs. In the in vitro study, we identified 6 deglycosylated metabolites of HA and EA, assigned M1-M6. In the in vivo study, we found all the deglycosylated metabolites in the intestinal contents after oral administration, and both the metabolites and their prototype components could be absorbed. Four metabolites were identified in the serum, 6 in the urine, and 4 in the feces. The saponins with different structures showed different absorption characteristics in rats. According to our results, deglycosylation is the main intestinal microflora-mediated metabolic pathway for SCSs, and both the SCSs and deglycosylated metabolites can be absorbed by intestine. This study improves the understanding of the metabolism of HA and EA by gut flora, which will be useful for further analysis of the bioactivity mechanism of SCSs. © 2017 Institute of Food Technologists®.

Battery control system for hybrid vehicle and method for controlling a hybrid vehicle battery

Science.gov (United States)

Bockelmann, Thomas R [Battle Creek, MI; Hope, Mark E [Marshall, MI; Zou, Zhanjiang [Battle Creek, MI; Kang, Xiaosong [Battle Creek, MI

2009-02-10

A battery control system for hybrid vehicle includes a hybrid powertrain battery, a vehicle accessory battery, and a prime mover driven generator adapted to charge the vehicle accessory battery. A detecting arrangement is configured to monitor the vehicle accessory battery's state of charge. A controller is configured to activate the prime mover to drive the generator and recharge the vehicle accessory battery in response to the vehicle accessory battery's state of charge falling below a first predetermined level, or transfer electrical power from the hybrid powertrain battery to the vehicle accessory battery in response to the vehicle accessory battery's state of charge falling below a second predetermined level. The invention further includes a method for controlling a hybrid vehicle powertrain system.

A hybrid air conditioner driven by a hybrid solar collector

Science.gov (United States)

Al-Alili, Ali

The objective of this thesis is to search for an efficient way of utilizing solar energy in air conditioning applications. The current solar Air Conditioners (A/C)s suffer from low Coefficient of Performance (COP) and performance degradation in hot and humid climates. By investigating the possible ways of utilizing solar energy in air conditioning applications, the bottlenecks in these approaches were identified. That resulted in proposing a novel system whose subsystem synergy led to a COP higher than unity. The proposed system was found to maintain indoor comfort at a higher COP compared to the most common solar A/Cs, especially under very hot and humid climate conditions. The novelty of the proposed A/C is to use a concentrating photovoltaic/thermal collector, which outputs thermal and electrical energy simultaneously, to drive a hybrid A/C. The performance of the hybrid A/C, which consists of a desiccant wheel, an enthalpy wheel, and a vapor compression cycle (VCC), was investigated experimentally. This work also explored the use of a new type of desiccant material, which can be regenerated with a low temperature heat source. The experimental results showed that the hybrid A/C is more effective than the standalone VCC in maintaining the indoor conditions within the comfort zone. Using the experimental data, the COP of the hybrid A/C driven by a hybrid solar collector was found to be at least double that of the current solar A/Cs. The innovative integration of its subsystems allows each subsystem to do what it can do best. That leads to lower energy consumption which helps reduce the peak electrical loads on electric utilities and reduces the consumer operating cost since less energy is purchased during the on peak periods and less solar collector area is needed. In order for the proposed A/C to become a real alternative to conventional systems, its performance and total cost were optimized using the experimentally validated model. The results showed that for an

Aspen Plus simulation of biomass integrated gasification combined cycle systems at corn ethanol plants

International Nuclear Information System (INIS)

Zheng, Huixiao; Kaliyan, Nalladurai; Morey, R. Vance

2013-01-01

Biomass integrated gasification combined cycle (BIGCC) systems and natural gas combined cycle (NGCC) systems are employed to provide heat and electricity to a 0.19 hm 3 y −1 (50 million gallon per year) corn ethanol plant using different fuels (syrup and corn stover, corn stover alone, and natural gas). Aspen Plus simulations of BIGCC/NGCC systems are performed to study effects of different fuels, gas turbine compression pressure, dryers (steam tube or superheated steam) for biomass fuels and ethanol co-products, and steam tube dryer exhaust treatment methods. The goal is to maximize electricity generation while meeting process heat needs of the plant. At fuel input rates of 110 MW, BIGCC systems with steam tube dryers provide 20–25 MW of power to the grid with system thermal efficiencies (net power generated plus process heat rate divided by fuel input rate) of 69–74%. NGCC systems with steam tube dryers provide 26–30 MW of power to the grid with system thermal efficiencies of 74–78%. BIGCC systems with superheated steam dryers provide 20–22 MW of power to the grid with system thermal efficiencies of 53–56%. The life-cycle greenhouse gas (GHG) emission reduction for conventional corn ethanol compared to gasoline is 39% for process heat with natural gas (grid electricity), 117% for BIGCC with syrup and corn stover fuel, 124% for BIGCC with corn stover fuel, and 93% for NGCC with natural gas fuel. These GHG emission estimates do not include indirect land use change effects. -- Highlights: •BIGCC and natural gas combined cycle systems at corn ethanol plants are simulated. •The best performance results in 25–30 MW power to grid. •The best performance results in 74–78% system thermal efficiencies. •GHG reduction for corn ethanol with BIGCC systems compared to gasoline is over 100%

Behavioral and spermatogenic hybrid male breakdown in Nasonia.

Science.gov (United States)

Clark, M E; O'Hara, F P; Chawla, A; Werren, J H

2010-03-01

Several reproductive barriers exist within the Nasonia species complex, including allopatry, premating behavioral isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioral sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviors, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared with wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviorally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than nonfunctional sperm, is different from most described cases of hybrid male sterility, and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioral sterility, and indicate that Wolbachia-induced hybrid incompatibility has arisen early in species divergence, relative to behavioral sterility and spermatogenic infertility.

Behavioural and spermatogenic hybrid male breakdown in Nasonia

Science.gov (United States)

Clark, Michael E.; O’Hara, F. Patrick; Chawla, Ankur; Werren, John H.

2010-01-01

Several reproductive barriers exists within the Nasonia species complex, including allopatry, premating behavioural isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioural sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviours, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared to wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviourally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than non-functional sperm, is different from most described cases of hybrid male sterility and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioural sterility, and indicated that Wolbachia induced hybrid incompatibility has arisen early in species divergence, relative to behavioural sterility and spermatogenic infertility. PMID:20087395

In situ hybridization at the electron microscope level: hybrid detection by autoradiography and colloidal gold.

Science.gov (United States)

Hutchison, N J; Langer-Safer, P R; Ward, D C; Hamkalo, B A

1982-11-01

In situ hybridization has become a standard method for localizing DNA or RNA sequences in cytological preparations. We developed two methods to extend this technique to the transmission electron microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope in situ hybridization. Radioactively labeled complementary RNA (cRNA) is hybridized to metaphase chromosomes deposited on electron microscope grids and fixed in 70 percent ethanol vapor; hybridixation site are detected by autoradiography. Specific and intense labeling of chromosomal centromeric regions is observed even after relatively short exposure times. Inerphase nuclei present in some of the metaphase chromosome preparations also show defined paatterms of satellite DNA labeling which suggests that satellite-containing regions are associate with each other during interphase. The sensitivity of this method is estimated to at least as good as that at the light microscope level while the resolution is improved at least threefold. The second method, which circumvents the use of autoradiogrphic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction is improved at least threefold. The second method, which circumvents the use of autoradiographic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction with an antibody against biotin and secondary antibody adsorbed to the surface of over centromeric heterochromatin and along the associated peripheral fibers. Labeling is on average

Internal combustion engines in hybrid vehicles

NARCIS (Netherlands)

Mourad, S.; Weijer, C.J.T. van de; Beckman, D.E.

1998-01-01

In this paper the use of internal combustion engines in hybrid powertrains is investigated. The substantial difference between the use of internal combustion engines in conventional and in hybrid vehicles mean that engines for hybrid vehicles should be designed specifically for the purpose. At the

Design Procedure for Hybrid Ventilation

DEFF Research Database (Denmark)

Heiselberg, Per; Tjelflaat, Per Olaf

Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilises and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation....... Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC....... The first ideas on a design procedure for hybrid ventilation is presented and the different types of design methods, that is needed in different phases of the design process, is discussed....

Design, analysis and modeling of a novel hybrid powertrain system based on hybridized automated manual transmission

Science.gov (United States)

Wu, Guang; Dong, Zuomin

2017-09-01

Hybrid electric vehicles are widely accepted as a promising short to mid-term technical solution due to noticeably improved efficiency and lower emissions at competitive costs. In recent years, various hybrid powertrain systems were proposed and implemented based on different types of conventional transmission. Power-split system, including Toyota Hybrid System and Ford Hybrid System, are well-known examples. However, their relatively low torque capacity, and the drive of alternative and more advanced designs encouraged other innovative hybrid system designs. In this work, a new type of hybrid powertrain system based hybridized automated manual transmission (HAMT) is proposed. By using the concept of torque gap filler (TGF), this new hybrid powertrain type has the potential to overcome issue of torque gap during gearshift. The HAMT design (patent pending) is described in details, from gear layout and design of gear ratios (EV mode and HEV mode) to torque paths at different gears. As an analytical tool, mutli-body model of vehicle equipped with this HAMT was built to analyze powertrain dynamics at various steady and transient modes. A gearshift was decomposed and analyzed based basic modes. Furthermore, a Simulink-SimDriveline hybrid vehicle model was built for the new transmission, driveline and vehicle modular. Control strategy has also been built to harmonically coordinate different powertrain components to realize TGF function. A vehicle launch simulation test has been completed under 30% of accelerator pedal position to reveal details during gearshift. Simulation results showed that this HAMT can eliminate most torque gap that has been persistent issue of traditional AMT, improving both drivability and performance. This work demonstrated a new type of transmission that features high torque capacity, high efficiency and improved drivability.

Insight and Evidence Motivating the Simplification of Dual-Analysis Hybrid Systems into Single-Analysis Hybrid Systems

Science.gov (United States)

Todling, Ricardo; Diniz, F. L. R.; Takacs, L. L.; Suarez, M. J.

2018-01-01

Many hybrid data assimilation systems currently used for NWP employ some form of dual-analysis system approach. Typically a hybrid variational analysis is responsible for creating initial conditions for high-resolution forecasts, and an ensemble analysis system is responsible for creating sample perturbations used to form the flow-dependent part of the background error covariance required in the hybrid analysis component. In many of these, the two analysis components employ different methodologies, e.g., variational and ensemble Kalman filter. In such cases, it is not uncommon to have observations treated rather differently between the two analyses components; recentering of the ensemble analysis around the hybrid analysis is used to compensated for such differences. Furthermore, in many cases, the hybrid variational high-resolution system implements some type of four-dimensional approach, whereas the underlying ensemble system relies on a three-dimensional approach, which again introduces discrepancies in the overall system. Connected to these is the expectation that one can reliably estimate observation impact on forecasts issued from hybrid analyses by using an ensemble approach based on the underlying ensemble strategy of dual-analysis systems. Just the realization that the ensemble analysis makes substantially different use of observations as compared to their hybrid counterpart should serve as enough evidence of the implausibility of such expectation. This presentation assembles numerous anecdotal evidence to illustrate the fact that hybrid dual-analysis systems must, at the very minimum, strive for consistent use of the observations in both analysis sub-components. Simpler than that, this work suggests that hybrid systems can reliably be constructed without the need to employ a dual-analysis approach. In practice, the idea of relying on a single analysis system is appealing from a cost-maintenance perspective. More generally, single-analysis systems avoid

Mirror hybrid reactor studies

International Nuclear Information System (INIS)

Bender, D.J.

1978-01-01

The hybrid reactor studies are reviewed. The optimization of the point design and work on a reference design are described. The status of the nuclear analysis of fast spectrum blankets, systems studies for fissile fuel producing hybrid reactor, and the mechanical design of the machine are reviewed

Configurations of hybrid-electric cars propulsion systems

OpenAIRE

Cundev, Dobri; Sarac, Vasilija; Stefanov, Goce

2011-01-01

Over the last few years, hybrid electric cars have taken significant role in automotive market. There are successful technological solutions of hybrid-electric propulsion systems implemented in commercial passenger cars. Every automobile manufacturer of hybrid vehicles has unique hybrid propulsion system. In this paper, all implemented systems are described, analyzed and compared.

Nuclear hybrid energy infrastructure

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Vivek; Tawfik, Magdy S.

2015-02-01

The nuclear hybrid energy concept is becoming a reality for the US energy infrastructure where combinations of the various potential energy sources (nuclear, wind, solar, biomass, and so on) are integrated in a hybrid energy system. This paper focuses on challenges facing a hybrid system with a Small Modular Reactor at its core. The core of the paper will discuss efforts required to develop supervisory control center that collects data, supports decision-making, and serves as an information hub for supervisory control center. Such a center will also be a model for integrating future technologies and controls. In addition, advanced operations research, thermal cycle analysis, energy conversion analysis, control engineering, and human factors engineering will be part of the supervisory control center. Nuclear hybrid energy infrastructure would allow operators to optimize the cost of energy production by providing appropriate means of integrating different energy sources. The data needs to be stored, processed, analyzed, trended, and projected at right time to right operator to integrate different energy sources.

Hybrid synchronization of hyperchaotic Lu system

Indian Academy of Sciences (India)

In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid ...

Process simulation of ethanol production from biomass gasification and syngas fermentation.

Science.gov (United States)

Pardo-Planas, Oscar; Atiyeh, Hasan K; Phillips, John R; Aichele, Clint P; Mohammad, Sayeed

2017-12-01

The hybrid gasification-syngas fermentation platform can produce more bioethanol utilizing all biomass components compared to the biochemical conversion technology. Syngas fermentation operates at mild temperatures and pressures and avoids using expensive pretreatment processes and enzymes. This study presents a new process simulation model developed with Aspen Plus® of a biorefinery based on a hybrid conversion technology for the production of anhydrous ethanol using 1200tons per day (wb) of switchgrass. The simulation model consists of three modules: gasification, fermentation, and product recovery. The results revealed a potential production of about 36.5million gallons of anhydrous ethanol per year. Sensitivity analyses were also performed to investigate the effects of gasification and fermentation parameters that are keys for the development of an efficient process in terms of energy conservation and ethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Feasibility study on the introduction of hybrid buses; Hybrid bus donyu kanosei chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The purpose of this research is to design pilot projects for introducing hybrid buses into the public transportation sector. This research also covers contents regarding hybrid buses with a trolley-collector motor and a diesel engine, to identify technical and economical problems and to analyze cost beneficiation using hybrid buses. The trolley parallel hybrid system has been employed for the feasibility study. This system has abundant operation results in Europe and the USA. Its battery is small or is not necessary, and the maintenance cost is also low. As a result of the feasibility study, reduction effects of CO2 emission were found out. When the CO2 generation at the power plant is not counted, the reduction effect was estimated to be 32% compared with the CO2 emission from diesel buses. When the CO2 generation at the power plant is considered, it was estimated to be 18%. The cost beneficiation was investigated for the cases of the transportations using trolley system surrounding a medium-scale terminal among large-scale housing development, tourist resort, and stations. The annual income is estimated to be larger than the annual payment in each case. It was found that the hybrid bus is economically established. 17 refs., 48 figs., 41 tabs.

Hybrid cryptosystem RSA - CRT optimization and VMPC

Science.gov (United States)

Rahmadani, R.; Mawengkang, H.; Sutarman

2018-03-01

Hybrid cryptosystem combines symmetric algorithms and asymmetric algorithms. This combination utilizes speeds on encryption/decryption processes of symmetric algorithms and asymmetric algorithms to secure symmetric keys. In this paper we propose hybrid cryptosystem that combine symmetric algorithms VMPC and asymmetric algorithms RSA - CRT optimization. RSA - CRT optimization speeds up the decryption process by obtaining plaintext with dp and p key only, so there is no need to perform CRT processes. The VMPC algorithm is more efficient in software implementation and reduces known weaknesses in RC4 key generation. The results show hybrid cryptosystem RSA - CRT optimization and VMPC is faster than hybrid cryptosystem RSA - VMPC and hybrid cryptosystem RSA - CRT - VMPC. Keyword : Cryptography, RSA, RSA - CRT, VMPC, Hybrid Cryptosystem.

Parametric systems analysis for ICF hybrid reactors

International Nuclear Information System (INIS)

Berwald, D.H.; Maniscalco, J.A.; Chapin, D.L.

1981-01-01

Parametric design and systems analysis for inertial confinement fusion-fission hybrids are presented. These results were generated as part of the Electric Power Research Institute (EPRI) sponsored Feasibility Assessment of Fusion-Fission Hybrids, using an Inertial Confinement Fusion (ICF) hybrid power plant design code developed in conjunction with the feasibility assessment. The SYMECON systems analysis code, developed by Westinghouse, was used to generate economic results for symbiotic electricity generation systems consisting of the hybrid and its client Light Water Reactors (LWRs). These results explore the entire fusion parameter space for uranium fast fission blanket hybrids, thorium fast fission blanket hybrids, and thorium suppressed fission blanket types are discussed, and system sensitivities to design uncertainties are explored

Electric/Hybrid Vehicle Simulation

Science.gov (United States)

Slusser, R. A.; Chapman, C. P.; Brennand, J. P.

1985-01-01

ELVEC computer program provides vehicle designer with simulation tool for detailed studies of electric and hybrid vehicle performance and cost. ELVEC simulates performance of user-specified electric or hybrid vehicle under user specified driving schedule profile or operating schedule. ELVEC performs vehicle design and life cycle cost analysis.

Assay of hybrid ribonuclease using a membrane filter-immobilized synthetic hybrid: application to the human leukemic cell

International Nuclear Information System (INIS)

Papaphilis, A.D.; Kamper, E.F.

1985-01-01

A method for assaying hybrid ribonuclease has been devised which utilizes as substrate the synthetic hybrid [ 3 H]polyriboadenylic acid [poly(rA)]:polydeoxythymidylic acid [poly(dT)] immobilized on the solid matrix of nitrocellulose filters. The hybridization on filter of [ 3 H]poly(rA) to poly(dT) has been explored in terms of efficacy of the process and the response of the product to RNase H. A pulse of uv irradiation of poly(dT) while in dry state on the filter increased its firm binding to the filter in a concentration-dependent manner, resulting in a concomitant increase of the yield of hybrid formation. The filter-immobilized hybrid was 95% resistant to RNase A but sensitive to RNase H. When stored in toluene in the cold the hybrid maintained its stability for over 6 months, as judged by its resistance to RNase A. The method offers a number of advantages over assays that use solution hybrids as substrates and was readily applicable in the screening of leukemic patients, in the leukocytes of which it has demonstrated increased RNase H levels

The tokamak hybrid reactor

International Nuclear Information System (INIS)

Kelly, J.L.; Rose, R.P.

1981-01-01

At a time when the potential benefits of various energy options are being seriously evaluated in many countries through-out the world, it is both timely and important to evaluate the practical application of fusion reactors for their economical production of nuclear fissile fuels from fertile fuels. The fusion hybrid reactor represents a concept that could assure the availability of adequate fuel supplies for a proven nuclear technology and have the potential of being an electrical energy source as opposed to an energy consumer as are the present fuel enrichment processes. Westinghouse Fusion Power Systems Department, under Contract No. EG-77-C-02-4544 with the Department of Energy, Office of Fusion Energy, has developed a preliminary conceptual design for an early twenty-first century fusion hybrid reactor called the commercial Tokamak Hybrid Reactor (CTHR). This design was developed as a first generation commercial plant producing fissile fuel to support a significant number of client Light Water Reactor (LWR) Plants. To the depth this study has been performed, no insurmountable technical problems have been identified. The study has provided a basis for reasonable cost estimates of the hybrid plants as well as the hybrid/LWR system busbar electricity costs. This energy system can be optimized to have a net cost of busbar electricity that is equivalent to the conventional LWR plant, yet is not dependent on uranium ore prices or standard enrichment costs, since the fusion hybrid can be fueled by numerous fertile fuel resources. A nearer-term concept is also defined using a beam driven fusion driver in lieu of the longer term ignited operating mode. (orig.)

Towers of hybrid mesons

International Nuclear Information System (INIS)

Semay, Claude; Buisseret, Fabien; Silvestre-Brac, Bernard

2009-01-01

A hybrid meson is a quark-antiquark pair in which, contrary to ordinary mesons, the gluon field is in an excited state. In the framework of constituent models, the interaction potential is assumed to be the energy of an excited string. An approximate, but accurate, analytical solution of the Schroedinger equation with such a potential is presented. When applied to hybrid charmonia and bottomonia, towers of states are predicted in which the masses are a linear function of a harmonic oscillator band number for the quark-antiquark pair. Such a formula could be a reliable guide for the experimental detection of heavy hybrid mesons.

Program Hybrid/GDH. Revision

International Nuclear Information System (INIS)

Blann, M.; Bisplinghoff, J.

1975-10-01

This code is the most recent in a series of codes for doing a-priori pre-equilibrium decay calculations. It has been written to permit the user to exercise many options at time of execution. It will, for example, permit calculation with either Hybrid model or the geometry dependent Hybrid model (GDH). Intranuclear transition rates can be calculated using either a nucleon-nucleon scattering approach (improved over earlier results) or based on the imaginary optical potential. Transition rates based on exciton lifetimes can be selected (as suggested in the Hybrid model formulation) or an average lifetime for each n-exciton configuration may be selected

Hybrid job shop scheduling

NARCIS (Netherlands)

Schutten, Johannes M.J.

1995-01-01

We consider the problem of scheduling jobs in a hybrid job shop. We use the term 'hybrid' to indicate that we consider a lot of extensions of the classic job shop, such as transportation times, multiple resources, and setup times. The Shifting Bottleneck procedure can be generalized to deal with

Diagnoses of hybrid hummingbirds (Aves: Trochilidae). 17. Documentation of the intrageneric hybrid (Archilochus colubris × Archilochus alexandri)

DEFF Research Database (Denmark)

Graves, Gary R.; Dittmann, Donna L.; Cardiff, Steven W.

2016-01-01

Although the breeding ranges of Archilochus alexandri (Black-chinned Hummingbird) and Archilochus colubris (Ruby throated Hummingbird) are narrowly parapatric in central Texas and central and southern Oklahoma, there have been few reports of hybridization in the literature and no well......-documented hybrid specimens. Here we provide a comprehensive assessment of two male hybrids collected, respectively, in Grayson County, Texas, and East Baton Rouge Parish, Louisiana. As has been the pattern in other hummingbird hybrids, both specimens exhibit a blended mosaic of plumage characters of the parental...

Analysis of Non-binary Hybrid LDPC Codes

OpenAIRE

Sassatelli, Lucile; Declercq, David

2008-01-01

In this paper, we analyse asymptotically a new class of LDPC codes called Non-binary Hybrid LDPC codes, which has been recently introduced. We use density evolution techniques to derive a stability condition for hybrid LDPC codes, and prove their threshold behavior. We study this stability condition to conclude on asymptotic advantages of hybrid LDPC codes compared to their non-hybrid counterparts.

Hybrid fission-fusion nuclear reactors

International Nuclear Information System (INIS)

Zucchetti, Massimo

2011-01-01

A fusion-fission hybrid could contribute to all components of nuclear power - fuel supply, electricity production, and waste management. The idea of the fusion-fission hybrid is many decades old. Several ideas, both new and revisited, have been investigated by hybrid proponents. These ideas appear to have attractive features, but they require various levels of advances in plasma science and fusion and nuclear technology. As a first step towards the development of hybrid reactors, fusion neutron sources can be considered as an option. Compact high-field tokamaks can be a candidate for being the neutron source in a fission-fusion hybrid, essentially due to their design characteristics, such as compact dimensions, high magnetic field, flexibility of operation. This study presents the development of a tokamak neutron source for a material testing facility using an Ignitor-based concept. The computed values show the potential of this neutron-rich device for fusion materials testing. Some full-power months of operation are sufficient to obtain relevant radiation damage values in terms of dpa. (Author)

On the complexity of the Saccharomyces bayanus taxon: hybridization and potential hybrid speciation.

Directory of Open Access Journals (Sweden)

Laura Pérez-Través

Full Text Available Although the genus Saccharomyces has been thoroughly studied, some species in the genus has not yet been accurately resolved; an example is S. bayanus, a taxon that includes genetically diverse lineages of pure and hybrid strains. This diversity makes the assignation and classification of strains belonging to this species unclear and controversial. They have been subdivided by some authors into two varieties (bayanus and uvarum, which have been raised to the species level by others. In this work, we evaluate the complexity of 46 different strains included in the S. bayanus taxon by means of PCR-RFLP analysis and by sequencing of 34 gene regions and one mitochondrial gene. Using the sequence data, and based on the S. bayanus var. bayanus reference strain NBRC 1948, a hypothetical pure S. bayanus was reconstructed for these genes that showed alleles with similarity values lower than 97% with the S. bayanus var. uvarum strain CBS 7001, and of 99-100% with the non S. cerevisiae portion in S. pastorianus Weihenstephan 34/70 and with the new species S. eubayanus. Among the S. bayanus strains under study, different levels of homozygosity, hybridization and introgression were found; however, no pure S. bayanus var. bayanus strain was identified. These S. bayanus hybrids can be classified into two types: homozygous (type I and heterozygous hybrids (type II, indicating that they have been originated by different hybridization processes. Therefore, a putative evolutionary scenario involving two different hybridization events between a S. bayanus var. uvarum and unknown European S. eubayanus-like strains can be postulated to explain the genomic diversity observed in our S. bayanus var. bayanus strains.

PV-HYBRID and MINI-GRID. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

Within the 3rd European Conference at the Centre de Congres in Aix en Provence (France) between 11th and 12th May, 2006, the following lessons were held: (1) Small electric networks: European drivers and projects for the integration of RES and DG into the electricity grids of the future (Manuel Sanchez-Jimenez); (2) PV hybrid system within mini grids - IEA PVPS programme (Meuch Konraf); (3) Renewables for the developing world (Alvaro Ponce Plaza); (4) Rural electicity supply using photovoltaic / - Diesel hybrid systems: Attractive for investors in the renewable energy sector? (Andreas Hahn); (5) Economic analysis of stand-alone and grid-connected photovoltaic systems under current tariff structure of Taiwan (Yaw-Juen Wang); (6) Using wind-PV-diesel hybrid system for electrification of remote village in Western Libya (N.M. Kreama); (7) Venezuela's renewable energy program for small towns and rural areas ''Sembrando Luz'' (Jorge Torres); (8) AeroSmart5, the professional, sysem-compatible small-scale wind energy converter will be tested in field tests (Fabian Jochem); (9) Lifetime, test procedures and recommendations for optimal operating strategies for lead-acid-batteries in renewable energy systems - A survey on results from European projects from the 5th framework programme (Rudi Kaiser); (10) Prototype of a reversible fuel cell system for autonomous power supplies (Tom Smolinska); (11) Interconnection management in microgrids (Michel Vandenbergh); (12) Control strategy for a small-scale stand-alone power system based on renewable energy and hydrogen (Harald Miland); (13) Standard renewable electricity supply for people in rural areas - mini-grids in western provinces of China (Michael Wollny); (14) The Brava island a ''100% renewable energy'' project (Jean-Christian Marcel); (15) Breakthrough to a new era of PV-hybrid systems with the help of standardised components communication? (Michael Mueller); (16) Standardized

Bucking the trend in wolf-dog hybridization: first evidence from europe of hybridization between female dogs and male wolves.

Science.gov (United States)

Hindrikson, Maris; Männil, Peep; Ozolins, Janis; Krzywinski, Andrzej; Saarma, Urmas

2012-01-01

Studies on hybridization have proved critical for understanding key evolutionary processes such as speciation and adaptation. However, from the perspective of conservation, hybridization poses a concern, as it can threaten the integrity and fitness of many wild species, including canids. As a result of habitat fragmentation and extensive hunting pressure, gray wolf (Canis lupus) populations have declined dramatically in Europe and elsewhere during recent centuries. Small and fragmented populations have persisted, but often only in the presence of large numbers of dogs, which increase the potential for hybridization and introgression to deleteriously affect wolf populations. Here, we demonstrate hybridization between wolf and dog populations in Estonia and Latvia, and the role of both genders in the hybridization process, using combined analysis of maternal, paternal and biparental genetic markers. Eight animals exhibiting unusual external characteristics for wolves - six from Estonia and two from Latvia - proved to be wolf-dog hybrids. However, one of the hybridization events was extraordinary. Previous field observations and genetic studies have indicated that mating between wolves and dogs is sexually asymmetrical, occurring predominantly between female wolves and male dogs. While this was also the case among the Estonian hybrids, our data revealed the existence of dog mitochondrial genomes in the Latvian hybrids and, together with Y chromosome and autosomal microsatellite data, thus provided the first evidence from Europe of mating between male wolves and female dogs. We discuss patterns of sexual asymmetry in wolf-dog hybridization.

Sequence-dependent theory of oligonucleotide hybridization kinetics

International Nuclear Information System (INIS)

Marimuthu, Karthikeyan; Chakrabarti, Raj

2014-01-01

A theoretical approach to the prediction of the sequence and temperature-dependent rate constants for oligonucleotide hybridization reactions has been developed based on the theory of relaxation kinetics. One-sided and two-sided melting reaction mechanisms for oligonucleotide hybridization reactions have been considered, analyzed, modified, and compared to select a physically consistent as well as robust model for prediction of the relaxation times of DNA hybridization reactions that agrees with the experimental evidence. The temperature- and sequence-dependent parameters of the proposed model have been estimated using available experimental data. The relaxation time model that we developed has been combined with the nearest neighbor model of hybridization thermodynamics to estimate the temperature- and sequence-dependent rate constants of an oligonucleotide hybridization reaction. The model-predicted rate constants are compared to experimentally determined rate constants for the same oligonucleotide hybridization reactions. Finally, we consider a few important applications of kinetically controlled DNA hybridization reactions

Hybrid intelligent engineering systems

CERN Document Server

Jain, L C; Adelaide, Australia University of

1997-01-01

This book on hybrid intelligent engineering systems is unique, in the sense that it presents the integration of expert systems, neural networks, fuzzy systems, genetic algorithms, and chaos engineering. It shows that these new techniques enhance the capabilities of one another. A number of hybrid systems for solving engineering problems are presented.

Electric-hybrid-vehicle simulation

Science.gov (United States)

Pasma, D. C.

The simulation of electric hybrid vehicles is to be performed using experimental data to model propulsion system components. The performance of an existing ac propulsion system will be used as the baseline for comparative purposes. Hybrid components to be evaluated include electrically and mechanically driven flywheels, and an elastomeric regenerative braking system.

Recent Advances in Immobilization Strategies for Glycosidases

Science.gov (United States)

Karav, Sercan; Cohen, Joshua L.; Barile, Daniela; de Moura Bell, Juliana Maria Leite Nobrega

2017-01-01

Glycans play important biological roles in cell-to-cell interactions, protection against pathogens, as well as in proper protein folding and stability, and are thus interesting targets for scientists. Although their mechanisms of action have been widely investigated and hypothesized, their biological functions are not well understood due to the lack of deglycosylation methods for large-scale isolation of these compounds. Isolation of glycans in their native state is crucial for the investigation of their biological functions. However, current enzymatic and chemical deglycosylation techniques require harsh pretreatment and reaction conditions (high temperature and use of detergents) that hinder the isolation of native glycan structures. Indeed, the recent isolation of new endoglycosidases that are able to cleave a wider variety of linkages and efficiently hydrolyze native proteins has opened up the opportunity to elucidate the biological roles of a higher variety of glycans in their native state. As an example, our research group recently isolated a novel Endo-β-N-acetylglucosaminidase from Bifidobacterium longum subsp. infantis ATCC 15697 (EndoBI-1) that cleaves N-N′-diacetyl chitobiose moieties found in the N-linked glycan (N-glycan) core of high mannose, hybrid, and complex N-glycans. This enzyme is also active on native proteins, which enables native glycan isolation, a key advantage when evaluating their biological activities. Efficient, stable, and economically viable enzymatic release of N-glycans requires the selection of appropriate immobilization strategies. In this review, we discuss the state-of-the-art of various immobilization techniques (physical adsorption, covalent binding, aggregation, and entrapment) for glycosidases, as well as their potential substrates and matrices. PMID:27718339

Graphene hybridization for energy storage applications.

Science.gov (United States)

Li, Xianglong; Zhi, Linjie

2018-05-08

Graphene has attracted considerable attention due to its unique two-dimensional structure, high electronic mobility, exceptional thermal conductivity, excellent optical transmittance, good mechanical strength, and ultrahigh surface area. To meet the ever increasing demand for portable electronic products, electric vehicles, smart grids, and renewable energy integrations, hybridizing graphene with various functions and components has been demonstrated to be a versatile and powerful strategy to significantly enhance the performance of various energy storage systems such as lithium-ion batteries, supercapacitors and beyond, because such hybridization can result in synergistic effects that combine the best merits of involved components and confer new functions and properties, thereby improving the charge/discharge efficiencies and capabilities, energy/power densities, and cycle life of these energy storage systems. This review will focus on diverse graphene hybridization principles and strategies for energy storage applications, and the proposed outline is as follows. First, graphene and its fundamental properties, followed by graphene hybrids and related hybridization motivation, are introduced. Second, the developed hybridization formulas of using graphene for lithium-ion batteries are systematically categorized from the viewpoint of material structure design, bulk electrode construction, and material/electrode collaborative engineering; the latest representative progress on anodes and cathodes of lithium-ion batteries will be reviewed following such classifications. Third, similar hybridization formulas for graphene-based supercapacitor electrodes will be summarized and discussed as well. Fourth, the recently emerging hybridization formulas for other graphene-based energy storage devices will be briefed in combination with typical examples. Finally, future prospects and directions on the exploration of graphene hybridization toward the design and construction of

Estimation of Power Production Potential from Natural Gas Pressure Reduction Stations in Pakistan Using ASPEN HYSYS

Directory of Open Access Journals (Sweden)

Imran Nazir Unar

2015-07-01

Full Text Available Pakistan is a gas rich but power poor country. It consumes approximately 1, 559 Billion cubic feet of natural gas annually. Gas is transported around the country in a system of pressurized transmission pipelines under a pressure range of 600-1000 psig exclusively operated by two state owned companies i.e. SNGPL (Sui Northern Gas Pipelines Limited and SSGCL (Sui Southern Gas Company Limited. The gas is distributed by reducing from the transmission pressure into distribution pressure up to maximum level of 150 psig at the city gate stations normally called SMS (Sales Metering Station. As a normal practice gas pressure reduction at those SMSs is accomplished in pressure regulators (PCVs or in throttle valves where isenthalpic expansion takes place without producing any energy. Pressure potential of natural gas is an untapped energy resource which is currently wasted by its throttling. This pressure reduction at SMS (pressure drop through SMS may also be achieved by expansion of natural gas in TE, which converts its pressure into the mechanical energy, which can be transmitted any loading device for example electric generator. The aim of present paper is to explore the expected power production potential of various Sales Metering Stations of SSGCL company in Pakistan. The model of sales metering station was developed in a standard flow sheeting software Aspen HYSYS®7.1 to calculate power and study other parameters when an expansion turbine is used instead of throttling valves. It was observed from the simulation results that a significant power (more than 140 KW can be produced at pressure reducing stations of SSGC network with gas flows more than 2.2 MMSCFD and pressure ration more than 1.3.

Drought's legacy: multiyear hydraulic deterioration underlies widespread aspen forest die-off and portends increased future risk.

Science.gov (United States)

Anderegg, William R L; Plavcová, Lenka; Anderegg, Leander D L; Hacke, Uwe G; Berry, Joseph A; Field, Christopher B

2013-04-01

Forest mortality constitutes a major uncertainty in projections of climate impacts on terrestrial ecosystems and carbon-cycle feedbacks. Recent drought-induced, widespread forest die-offs highlight that climate change could accelerate forest mortality with its diverse and potentially severe consequences for the global carbon cycle, ecosystem services, and biodiversity. How trees die during drought over multiple years remains largely unknown and precludes mechanistic modeling and prediction of forest die-off with climate change. Here, we examine the physiological basis of a recent multiyear widespread die-off of trembling aspen (Populus tremuloides) across much of western North America. Using observations from both native trees while they are dying and a rainfall exclusion experiment on mature trees, we measure hydraulic performance over multiple seasons and years and assess pathways of accumulated hydraulic damage. We test whether accumulated hydraulic damage can predict the probability of tree survival over 2 years. We find that hydraulic damage persisted and increased in dying trees over multiple years and exhibited few signs of repair. This accumulated hydraulic deterioration is largely mediated by increased vulnerability to cavitation, a process known as cavitation fatigue. Furthermore, this hydraulic damage predicts the probability of interyear stem mortality. Contrary to the expectation that surviving trees have weathered severe drought, the hydraulic deterioration demonstrated here reveals that surviving regions of these forests are actually more vulnerable to future droughts due to accumulated xylem damage. As the most widespread tree species in North America, increasing vulnerability to drought in these forests has important ramifications for ecosystem stability, biodiversity, and ecosystem carbon balance. Our results provide a foundation for incorporating accumulated drought impacts into climate-vegetation models. Finally, our findings highlight the

Interspecific Hybridization within Ornamental Plants

DEFF Research Database (Denmark)

Kuligowska, Katarzyna

commercially important genera of ornamental plants: Kalanchoë and Hibiscus. The nature of hybridization barriers hampering hybrid production was investigated during pre- and post-fertilization stages. For each genus the interspecific crosses of Kalanchoë species and Hibiscus species, abnormal germination...... and growth of pollen tubes, as well as lower frequencies of pollen tubes were observed in specific cross-combinations. Post-fertilization barriers related to endosperm development and hybrid incompatibility were also observed in Kalanchoë and Hibiscus genus, respectively. Qualitative and quantitative...

Spatial sorting promotes the spread of maladaptive hybridization

Science.gov (United States)

Lowe, Winsor H.; Muhlfeld, Clint C.; Allendorf, Fred W.

2015-01-01

Invasive hybridization is causing loss of biodiversity worldwide. The spread of such introgression can occur even when hybrids have reduced Darwinian fitness, which decreases the frequency of hybrids due to low survival or reproduction through time. This paradox can be partially explained by spatial sorting, where genotypes associated with dispersal increase in frequency at the edge of expansion, fueling further expansion and allowing invasive hybrids to increase in frequency through space rather than time. Furthermore, because all progeny of a hybrid will be hybrids (i.e., will possess genes from both parental taxa), nonnative admixture in invaded populations can increase even when most hybrid progeny do not survive. Broader understanding of spatial sorting is needed to protect native biodiversity.

Reactivity limitations on the performance of hybrid reactors

International Nuclear Information System (INIS)

Piera, M.; Martinez-Val, J.M.

1994-01-01

A neutronic theory for characterizing the hybrid blanket physics is used to show that hybrid performances are limited because of reactivity restrictions. The hybrid must always remain subcritical, even in abnormal conditions. For hybrids devoted to energy production by multiplication of the neutron source power, the restriction is particularly strong, and the electricity recirculation fraction to feed the plant can be too large for its economic feasibility. In hybrids used to breed fissile fuel, the power of LWR maintained by power unit of the hybrid is also limited (to a factor of 10, approx.). (author)

Hybrid Arrays for Chemical Sensing

Science.gov (United States)

Kramer, Kirsten E.; Rose-Pehrsson, Susan L.; Johnson, Kevin J.; Minor, Christian P.

In recent years, multisensory approaches to environment monitoring for chemical detection as well as other forms of situational awareness have become increasingly popular. A hybrid sensor is a multimodal system that incorporates several sensing elements and thus produces data that are multivariate in nature and may be significantly increased in complexity compared to data provided by single-sensor systems. Though a hybrid sensor is itself an array, hybrid sensors are often organized into more complex sensing systems through an assortment of network topologies. Part of the reason for the shift to hybrid sensors is due to advancements in sensor technology and computational power available for processing larger amounts of data. There is also ample evidence to support the claim that a multivariate analytical approach is generally superior to univariate measurements because it provides additional redundant and complementary information (Hall, D. L.; Linas, J., Eds., Handbook of Multisensor Data Fusion, CRC, Boca Raton, FL, 2001). However, the benefits of a multisensory approach are not automatically achieved. Interpretation of data from hybrid arrays of sensors requires the analyst to develop an application-specific methodology to optimally fuse the disparate sources of data generated by the hybrid array into useful information characterizing the sample or environment being observed. Consequently, multivariate data analysis techniques such as those employed in the field of chemometrics have become more important in analyzing sensor array data. Depending on the nature of the acquired data, a number of chemometric algorithms may prove useful in the analysis and interpretation of data from hybrid sensor arrays. It is important to note, however, that the challenges posed by the analysis of hybrid sensor array data are not unique to the field of chemical sensing. Applications in electrical and process engineering, remote sensing, medicine, and of course, artificial

Genome-wide mapping in a house mouse hybrid zone reveals hybrid sterility loci and Dobzhansky-Muller interactions.

Science.gov (United States)

Turner, Leslie M; Harr, Bettina

2014-12-09

Mapping hybrid defects in contact zones between incipient species can identify genomic regions contributing to reproductive isolation and reveal genetic mechanisms of speciation. The house mouse features a rare combination of sophisticated genetic tools and natural hybrid zones between subspecies. Male hybrids often show reduced fertility, a common reproductive barrier between incipient species. Laboratory crosses have identified sterility loci, but each encompasses hundreds of genes. We map genetic determinants of testis weight and testis gene expression using offspring of mice captured in a hybrid zone between M. musculus musculus and M. m. domesticus. Many generations of admixture enables high-resolution mapping of loci contributing to these sterility-related phenotypes. We identify complex interactions among sterility loci, suggesting multiple, non-independent genetic incompatibilities contribute to barriers to gene flow in the hybrid zone.

Hybrid soft computing approaches research and applications

CERN Document Server

Dutta, Paramartha; Chakraborty, Susanta

2016-01-01

The book provides a platform for dealing with the flaws and failings of the soft computing paradigm through different manifestations. The different chapters highlight the necessity of the hybrid soft computing methodology in general with emphasis on several application perspectives in particular. Typical examples include (a) Study of Economic Load Dispatch by Various Hybrid Optimization Techniques, (b) An Application of Color Magnetic Resonance Brain Image Segmentation by ParaOptiMUSIG activation Function, (c) Hybrid Rough-PSO Approach in Remote Sensing Imagery Analysis,  (d) A Study and Analysis of Hybrid Intelligent Techniques for Breast Cancer Detection using Breast Thermograms, and (e) Hybridization of 2D-3D Images for Human Face Recognition. The elaborate findings of the chapters enhance the exhibition of the hybrid soft computing paradigm in the field of intelligent computing.

Thermal simulation of a cooling system of hybrid commercial vehicles; Thermalsimulation eine Hybrid-LKW-Kuehlsystems

Energy Technology Data Exchange (ETDEWEB)

Stroh, Christoph; Schnoerch, Stefan; Rathberger, Christian [Magna Powertrain Engineering Center Steyr GmbH und Co. KG, St. Valentin (Austria)

2012-11-01

In the past few years hybrid vehicles have been in the center of automotive engineering efforts, in particular in the field of passenger cars. But hybrid powertrains will also be important for commercial trucks. This focus on hybrid vehicles leads to high demands on thermal management since the additional components in a hybrid vehicle need appropriate cooling or even heating. In the given paper the simulation of a complete cooling system of a hybrid commercial vehicle will be explained. For this virtual examination the commercial 1D thermal management software KULI will be used, a co-simulation with several programs will not be done deliberately. Yet all aspects which are relevant for a global assessment of the thermal management are considered. The main focus is put on the investigation of appropriate concepts for the fluid circuits, including low and high temperature circuits, electric water pumps, etc. Moreover, also a refrigerant circuit with a chiller for active battery cooling will be used, the appropriate control strategy is implemented as well. For simulating transient profiles a simple driving simulation model is included, using road profile, ambient conditions, and various vehicle parameters as input. In addition an engine model is included which enables the investigation of fuel consumption potentials. This simulation model shows how the thermal management of a hybrid vehicle can be investigated with a single program and with reasonable effort. (orig.)

Magnetite Dissolution Performance of HYBRID-II Decontamination Process

International Nuclear Information System (INIS)

Kim, Seonbyeong; Lee, Woosung; Won, Huijun; Moon, Jeikwon; Choi, Wangkyu

2014-01-01

In this study, we conducted the magnetite dissolution performance test of HYBRID-II (Hydrazine Based Reductive metal Ion Decontamination with sulfuric acid) as a part of decontamination process development. Decontamination performance of HYBRID process was successfully tested with the results of the acceptable decontamination factor (DF) in the previous study. While following-up studies such as the decomposition of the post-decontamination HYBRID solution and corrosion compatibility on the substrate metals of the target reactor coolant system have been continued, we also seek for an alternate version of HYBRID process suitable especially for decommissioning. Inspired by the relationship between the radius of reacting ion and the reactivity, we replaced the nitrate ion in HYBRID with bigger sulfate ion to accommodate the dissolution reaction and named HYBRID-II process. As a preliminary step for the decontamination performance, we tested the magnetite dissolution performance of developing HYBRID-II process and compared the results with those of HYBRID process. HYBRID process developed previously is known have the acceptable decontamination performance, but the relatively larger volume of secondary waste induced by anion exchange resin to treat nitrate ion is the one of the problems related in the development of HYBRID process to be applicable. Therefore we alternatively devised HYBRID-II process using sulfuric acid and tested its dissolution of magnetite in numerous conditions. From the results shown in this study, we can conclude that HYBRID-II process improves the decontamination performance and potentially reduces the volume of secondary waste. Rigorous tests with metal oxide coupons obtained from reactor coolant system will be followed to prove the robustness of HYBRID-II process in the future

Current status of hybrid coronary revascularization.

Science.gov (United States)

Jaik, Nikhil P; Umakanthan, Ramanan; Leacche, Marzia; Solenkova, Natalia; Balaguer, Jorge M; Hoff, Steven J; Ball, Stephen K; Zhao, David X; Byrne, John G

2011-10-01

Hybrid coronary revascularization combines coronary artery bypass surgery with percutaneous coronary intervention techniques to treat coronary artery disease. The potential benefits of such a technique are to offer the patients the best available treatments for coronary artery disease while minimizing the risks of the surgery. Hybrid coronary revascularization has resulted in the establishment of new 'hybrid operating suites', which incorporate and integrate the capabilities of a cardiac surgery operating room with that of an interventional cardiology laboratory. Hybrid coronary revascularization has greatly augmented teamwork and cooperation between both fields and has demonstrated encouraging as well as good initial outcomes.

Do Hybrid Trees Inherit Invasive Characteristics? Fruits of Corymbia torelliana X C. citriodora Hybrids and Potential for Seed Dispersal by Bees.

Science.gov (United States)

Wallace, Helen Margaret; Leonhardt, Sara Diana

2015-01-01

Tree invasions have substantial impacts on biodiversity and ecosystem functioning, and trees that are dispersed by animals are more likely to become invasive. In addition, hybridisation between plants is well documented as a source of new weeds, as hybrids gain new characteristics that allow them to become invasive. Corymbia torelliana is an invasive tree with an unusual animal dispersal mechanism: seed dispersal by stingless bees, that hybridizes readily with other species. We examined hybrids between C. torelliana and C. citriodora subsp. citriodora to determine whether hybrids have inherited the seed dispersal characteristics of C. torelliana that allow bee dispersal. Some hybrid fruits displayed the characteristic hollowness, resin production and resin chemistry associated with seed dispersal by bees. However, we did not observe bees foraging on any hybrid fruits until they had been damaged. We conclude that C. torelliana and C. citriodora subsp. citriodora hybrids can inherit some fruit characters that are associated with dispersal by bees, but we did not find a hybrid with the complete set of characters that would enable bee dispersal. However, around 20,000 hybrids have been planted in Australia, and ongoing monitoring is necessary to identify any hybrids that may become invasive.

Principle, function, experiences, hybrid chilled ceilings; Prinzip, Funktion, Erfahrungen. Hybrid-Kuehldecken

Energy Technology Data Exchange (ETDEWEB)

Schulz, Uwe W. [Hochschule Luzern (Switzerland). Technik und Architektur

2010-12-15

Hybrid chilled ceilings combine a radiation chilled ceiling with thermal activations of a concrete ceiling. The activation permits the utilization of alternative and/or small cold generators for the efficient night cooling. The traditional chilled ceiling grants a speedy reaction to load variations as well as a reduction of the reverberation periods. In addition, the combination supplies a draught-free insertion of air. Beside established solutions, MWH Barcol-Air (Staefa, Switzerland) also offers project-specific hybrid chilled ceilings.

Hybrid uncertainty-based design optimization and its application to hybrid rocket motors for manned lunar landing

Directory of Open Access Journals (Sweden)

Hao Zhu

2017-04-01

Full Text Available Design reliability and robustness are getting increasingly important for the general design of aerospace systems with many inherently uncertain design parameters. This paper presents a hybrid uncertainty-based design optimization (UDO method developed from probability theory and interval theory. Most of the uncertain design parameters which have sufficient information or experimental data are classified as random variables using probability theory, while the others are defined as interval variables with interval theory. Then a hybrid uncertainty analysis method based on Monte Carlo simulation and Taylor series interval analysis is developed to obtain the uncertainty propagation from the design parameters to system responses. Three design optimization strategies, including deterministic design optimization (DDO, probabilistic UDO and hybrid UDO, are applied to the conceptual design of a hybrid rocket motor (HRM used as the ascent propulsion system in Apollo lunar module. By comparison, the hybrid UDO is a feasible method and can be effectively applied to the general design of aerospace systems.

Hybrid uncertainty-based design optimization and its application to hybrid rocket motors for manned lunar landing

Institute of Scientific and Technical Information of China (English)

Zhu Hao; Tian Hui; Cai Guobiao

2017-01-01

Design reliability and robustness are getting increasingly important for the general design of aerospace systems with many inherently uncertain design parameters. This paper presents a hybrid uncertainty-based design optimization (UDO) method developed from probability theory and interval theory. Most of the uncertain design parameters which have sufficient information or experimental data are classified as random variables using probability theory, while the others are defined as interval variables with interval theory. Then a hybrid uncertainty analysis method based on Monte Carlo simulation and Taylor series interval analysis is developed to obtain the uncer-tainty propagation from the design parameters to system responses. Three design optimization strategies, including deterministic design optimization (DDO), probabilistic UDO and hybrid UDO, are applied to the conceptual design of a hybrid rocket motor (HRM) used as the ascent propulsion system in Apollo lunar module. By comparison, the hybrid UDO is a feasible method and can be effectively applied to the general design of aerospace systems.

Introgressive hybridization as a promoter of genome reshuffling in natural homoploid fish hybrids (Cyprinidae, Leuciscinae)

Czech Academy of Sciences Publication Activity Database

Pereira, C. S.; Aboim, M. A.; Ráb, Petr; Collares-Pereira, M. J.

2014-01-01

Roč. 112, č. 3 (2014), s. 343-350 ISSN 0018-067X Institutional support: RVO:67985904 Keywords : comparative genome hybridization * hybrid zones * introgression Subject RIV: EG - Zoology Impact factor: 3.805, year: 2014

Close Look at Hybrid Vehicle Loyalty and Ownership

Energy Technology Data Exchange (ETDEWEB)

Hwang, Ho-Ling [ORNL; Chin, Shih-Miao [ORNL; Wilson, Daniel W [ORNL; Oliveira Neto, Francisco Moraes [ORNL; Taylor, Rob D [ORNL

2013-01-01

In a news release dated April 9, 2012, Polk stated that only 35% of hybrid owners bought a hybrid again when they returned to market in 2011. These findings were based on an internal study conducted by Polk. The study also indicated that if repurchase behavior among the high volume audience of Toyota Prius owners wasn t factored in; hybrid loyalty would drop to under 25%. This news release has generated a lot of interest and concern by the automobile industry as well as consumers, since it was published, and caused many to think about the idea of hybrid loyalty as well as factors that influence consumers. Most reactions to the 35% hybrid loyalty dealt with concerns of the viability of hybrid technology as part of the solution to address transportation energy challenges. This paper attempts to shed more light on Polk s hybrid loyalty study as well as explore several information sources concerning hybrid loyalty status. Specifically, major factors that might impact the selection and acquisition of hybrid vehicles are addressed. This includes investigating the associations between hybrid market shares and influencing factors like fuel price and hybrid incentives, as well as the availability of hybrid models and other highly fuel efficient vehicle options. This effort is not in-depth study, but rather a short study to see if Polk s claim could be validated. This study reveals that Polk s claim was rather misleading because its definition of loyalty was very narrow. This paper also suggests that Polk s analysis failed to account for some very important factors, raising the question of whether it is fair to compare a vehicle drive train option (which hybrids are) with a vehicle brand in terms of loyalty and also raises the question of whether hybrid loyalty is even a valid point to consider. This report maintains that Polk s study does not prove that hybrid owners were dissatisfied with their vehicles, which was a common theme among reporting news agencies when Polk

Hydraulic Hybrid Fleet Vehicle Testing | Transportation Research | NREL

Science.gov (United States)

Hydraulic Hybrid Fleet Vehicle Evaluations Hydraulic Hybrid Fleet Vehicle Evaluations How Hydraulic Hybrid Vehicles Work Hydraulic hybrid systems can capture up to 70% of the kinetic energy that would -pressure reservoir to a high-pressure accumulator. When the vehicle accelerates, fluid in the high-pressure

Hybrid reactors: Nuclear breeding or energy production?

International Nuclear Information System (INIS)

Piera, Mireia; Lafuente, Antonio; Abanades, Alberto; Martinez-Val, J.M.

2010-01-01

After reviewing the long-standing tradition on hybrid research, an assessment model is presented in order to characterize the hybrid performance under different objectives. In hybrids, neutron multiplication in the subcritical blanket plays a major role, not only for energy production and nuclear breeding, but also for tritium breeding, which is fundamental requirement in fusion-fission hybrids. All three objectives are better achieved with high values of the neutron multiplication factor (k-eff) with the obvious and fundamental limitation that it cannot reach criticality under any event, particularly, in the case of a loss of coolant accident. This limitation will be very important in the selection of the coolant. Some general considerations will be proposed, as guidelines for assessing the hybrid potential in a given scenario. Those guidelines point out that hybrids can be of great interest for the future of nuclear energy in a framework of Sustainable Development, because they can contribute to the efficient exploitation of nuclear fuels, with very high safety features. Additionally, a proposal is presented on a blanket specially suited for fusion-fission hybrids, although this reactor concept is still under review, and new work is needed for identifying the most suitable blanket composition, which can vary depending on the main objective of the hybrid.

Hybrid spacecraft attitude control system

Directory of Open Access Journals (Sweden)

Renuganth Varatharajoo

2016-02-01

Full Text Available The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.

Hybrid system concepts

International Nuclear Information System (INIS)

Landeyro, P.A.

1995-01-01

Hybrid systems studied for fissile material production, were reconsidered for minor actinide and long-lived fission product destruction as alternative to the traditional final disposal of nuclear waste. Now there are attempts to extend the use of the concepts developed for minor actinide incineration to plutonium burning. The most promising hybrid system concept considers fuel and target both as liquids. From the results obtained, the possibility to adopt composite targets seems the most promising solution, but still there remains the problem of Pu production, not acceptable in a burning system. This kind of targets can be mainly used for fissile material production, while for accelerator driven burners it is most convenient to use a liquid lead target. The most suitable solvent is heavy water for minor actinide annihilation in the blanket of a hybrid system. Due to the criticality conditions and the necessity of electric energy production, the blanket using plutonium dissolved in molten salts is the most convenient one. (author)

Asymmetric Hybrid Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chumanov, George [Clemson Univ., SC (United States)

2015-11-05

Hybrid Nanoparticles (AHNs) are rationally-designed multifunctional nanostructures and novel building blocks for the next generation of advanced materials and devices. Nanoscale materials attract considerable interest because of their unusual properties and potential for practical applications. Most of the activity in this field is focused on the synthesis of homogeneous nanoparticles from metals, metal oxides, semiconductors, and polymers. It is well recognized that properties of nanoparticles can be further enhanced if they are made as hybrid structures. This program is concerned with the synthesis, characterization, and application of such hybrid structures termed AHNs. AHNs are composed of a homogeneous core and several caps of different materials deposited on its surface (Fig. 1). Combined properties of the core and the caps as well as new properties that arise from core-cap and cap-cap interactions render AHNs multifunctional. In addition, specific chemical reactivity of the caps enables directional self-assembly of AHNs into complex architectures that are not possible with only spherical nanoparticles.

Hybrid pine for tough sites

International Nuclear Information System (INIS)

Davidson, W.H.

1994-01-01

A test planting of 30 first- and second-generation pitch x loblolly pine (pinus rigida x P. taeda) hybrids was established on a West Virginia minesoil in 1985. The site was considered orphaned because earlier attempts at revegetation were unsuccessful. The soil was acid (pH 4.6), lacking in nutrients, and compacted. Vegetation present at the time of planting consisted of a sparse cover of tall fescue (Festuca arundinacea) and poverty grass (Danthonia spicata) and a few sourwood (Oxydendrum arboreum) and mountain laurel (Kalmia latifolia) seedlings. In the planting trial, 30 different hybrids were set out in 4 tree linear plots replicated 5 times. The seedlings had been grown in containers for 1 yr before outplanting. Evaluations made after 6 growing seasons showed overall plantation survival was 93%; six hybrids and one open-pollinated cross survived 100%. Individual tree heights ranged from 50 to 425 cm with a plantation average of 235 cm (7.7 ft). Eleven of the hybrids had average heights that exceeded the plantation average. Another test planting of tree and shrub species on this site has very poor survival. Therefore, pitch x loblolly hybrid pine can be recommended for reclaiming this and similar sites

Case for the fusion hybrid

International Nuclear Information System (INIS)

Rose, R.P.

1981-01-01

The use of nuclear fusion to produce fuel for nuclear fission power stations is discussed in the context of a crucial need for future energy options. The fusion hybrid is first considered as an element in the future of nuclear fission power to provide long term assurance of adequate fuel supplies for both breeder and convertor reactors. Generic differences in neutronic characteristics lead to a fuel production potential of fusion-fission hybrid systems which is significantly greater than that obtainable with fission systems alone. Furthermore, cost benefit studies show a variety of scenarios in which the hybrid offers sufficient potential to justify development costs ranging in the tens of billions of dollars. The hybrid is then considered as an element in the ultimate development of fusion electric power. The hybrid offers a near term application of fusion where experience with the requisite technologies can be derived as a vital step in mapping a credible route to eventual commercial feasibility of pure fusion systems. Finally, the criteria for assessment of future energy options are discussed with prime emphasis on the need for rational comparision of alternatives

Hybrid perovskites: Approaches towards light-emitting devices

KAUST Repository

Alias, Mohd Sharizal

2016-10-06

The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted extensive research for photonic device applications. Using the bromide halide as an example, we present key approaches of our work towards realizing efficient perovskites based light-emitters. The approaches involved determination of optical constants for the hybrid perovskites thin films, fabrication of photonic nanostructures in the form of subwavelength grating reflector patterned directly on the hybrid perovskites as light manipulation layer, and enhancing the emission property of the hybrid perovskites by using microcavity structure. Our results provide a platform for realization of hybrid perovskites based light-emitting devices for solid-state lighting and display applications. © 2016 IEEE.

Hybrid perovskites: Approaches towards light-emitting devices

KAUST Repository

Alias, Mohd Sharizal; Dursun, Ibrahim; Priante, Davide; Saidaminov, Makhsud I.; Ng, Tien Khee; Bakr, Osman; Ooi, Boon S.

2016-01-01

The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted extensive research for photonic device applications. Using the bromide halide as an example, we present key approaches of our work towards realizing efficient perovskites based light-emitters. The approaches involved determination of optical constants for the hybrid perovskites thin films, fabrication of photonic nanostructures in the form of subwavelength grating reflector patterned directly on the hybrid perovskites as light manipulation layer, and enhancing the emission property of the hybrid perovskites by using microcavity structure. Our results provide a platform for realization of hybrid perovskites based light-emitting devices for solid-state lighting and display applications. © 2016 IEEE.

Hybrid colloidal plasmonic-photonic crystals.

Science.gov (United States)

Romanov, Sergei G; Korovin, Alexander V; Regensburger, Alois; Peschel, Ulf

2011-06-17

We review the recently emerged class of hybrid metal-dielectric colloidal photonic crystals. The hybrid approach is understood as the combination of a dielectric photonic crystal with a continuous metal film. It allows to achieve a strong modification of the optical properties of photonic crystals by involving the light scattering at electronic excitations in the metal component into moulding of the light flow in series to the diffraction resonances occurring in the body of the photonic crystal. We consider different realizations of hybrid plasmonic-photonic crystals based on two- and three-dimensional colloidal photonic crystals in association with flat and corrugated metal films. In agreement with model calculations, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tuneable functionality of these crystals. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimizing hybrid spreading in metapopulations.

Science.gov (United States)

Zhang, Changwang; Zhou, Shi; Miller, Joel C; Cox, Ingemar J; Chain, Benjamin M

2015-04-29

Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics.

Mitochondrial Recombination and Introgression during Speciation by Hybridization.

Science.gov (United States)

Leducq, Jean-Baptiste; Henault, Mathieu; Charron, Guillaume; Nielly-Thibault, Lou; Terrat, Yves; Fiumera, Heather L; Shapiro, B Jesse; Landry, Christian R

2017-08-01

Genome recombination is a major source of genotypic diversity and contributes to adaptation and speciation following interspecies hybridization. The contribution of recombination in these processes has been thought to be largely limited to the nuclear genome because organelles are mostly uniparentally inherited in animals and plants, which prevents recombination. Unicellular eukaryotes such as budding yeasts do, however, transmit mitochondria biparentally, suggesting that during hybridization, both parents could provide alleles that contribute to mitochondrial functions such as respiration and metabolism in hybrid populations or hybrid species. We examined the dynamics of mitochondrial genome transmission and evolution during speciation by hybridization in the natural budding yeast Saccharomyces paradoxus. Using population-scale mitochondrial genome sequencing in two endemic North American incipient species SpB and SpC and their hybrid species SpC*, we found that both parental species contributed to the hybrid mitochondrial genome through recombination. We support our findings by showing that mitochondrial recombination between parental types is frequent in experimental crosses that recreate the early step of this speciation event. In these artificial hybrids, we observed that mitochondrial genome recombination enhances phenotypic variation among diploid hybrids, suggesting that it could play a role in the phenotypic differentiation of hybrid species. Like the nuclear genome, the mitochondrial genome can, therefore, also play a role in hybrid speciation. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Hybrid computing - Generalities and bibliography

International Nuclear Information System (INIS)

Neel, Daniele

1970-01-01

This note presents the content of a research thesis. It describes the evolution of hybrid computing systems, discusses the benefits and shortcomings of analogue or hybrid systems, discusses the building up of an hybrid system (requires properties), comments different possible uses, addresses the issues of language and programming, discusses analysis methods and scopes of application. An appendix proposes a bibliography on these issues and notably the different scopes of application (simulation, fluid dynamics, biology, chemistry, electronics, energy, errors, space, programming languages, hardware, mechanics, and optimisation of equations or processes, physics) [fr

Evolution of hybrid defect networks

International Nuclear Information System (INIS)

Martins, C. J. A. P.

2009-01-01

We apply a recently developed analytic model for the evolution of monopole networks to the case of monopoles attached to one string, usually known as hybrid networks. We discuss scaling solutions for both local and global hybrid networks, and also find an interesting application for the case of vortons. Our quantitative results agree with previous estimates in indicating that the hybrid networks will usually annihilate soon after the string-forming phase transition. However, we also show that in some specific circumstances these networks can survive considerably more than a Hubble time.

Evolution and molecular control of hybrid incompatibility in plants

Directory of Open Access Journals (Sweden)

Chen Chen

2016-08-01

Full Text Available Postzygotic reproductive isolation (RI plays an important role in speciation. According to the stage at which it functions and the symptoms it displays, postzygotic RI can be called hybrid inviability, hybrid weakness or necrosis, hybrid sterility, or hybrid breakdown. In this review, we summarized new findings about hybrid incompatibilities in plants, most of which are from studies on Arabidopsis and rice. Recent progress suggests that hybrid incompatibility is a by-product of co-evolution either with parasitic selfish elements in the genome or with invasive microbes in the natural environment. We discuss the environmental influences on the expression of hybrid incompatibility and the possible effects of environment-dependent hybrid incompatibility on sympatric speciation. We also discuss the role of domestication on the evolution of hybrid incompatibilities.

Car makers: the hybrid car stirs up competition; Constructeurs automobiles: la voiture hybride attise la concurrence

Energy Technology Data Exchange (ETDEWEB)

Bocquet, P.Y.; Dumas, A.

2006-03-15

The success of clean vehicles has favored the hybrid technology. Toyota has drawn away from its competitors which today have to make up their leeway. Hybridization has the advantage to be able to be adapted to any energy source type. It has been adapted to gasoline engines first, but it is gaining diesel engines and trucks too. However, the over-cost of this technology remains today the main drawback of hybrid vehicles. (J.S.)

Conceptual innovations in hybrid reactors

International Nuclear Information System (INIS)

Greenspan, E.; Miley, G.H.

1980-01-01

A number of innovations in the conception of fusion-fission hybrid reactors, including the blanket, the fusion driver, the coupling of the fusion and the fission components as well as the application of hybrid reactors are described, and their feasibility assessed

Comparison performance of split plug-in hybrid electric vehicle and hybrid electric vehicle using ADVISOR

Directory of Open Access Journals (Sweden)

Mohd Rashid Muhammad Ikram

2017-01-01

Full Text Available Electric vehicle suffers from relatively short range and long charging times and consequently has not become an acceptable solution to the automotive consumer. The addition of an internal combustion engine to extend the range of the electric vehicle is one method of exploiting the high efficiency and lack of emissions of the electric vehicle while retaining the range and convenient refuelling times of a conventional gasoline powered vehicle. The term that describes this type of vehicle is a hybrid electric vehicle. Many configurations of hybrid electric vehicles have been designed and implemented, namely the series, parallel and power-split configurations. This paper discusses the comparison between Split Plug-in Hybrid Electric Vehicle(SPHEV and Hybrid Electric Vehicle(HEV. Modelling methods such as physics-based Resistive Companion Form technique and Bond Graph method are presented with powertrain component and system modelling examples. The modelling and simulation capability of existing tools such as ADvanced VehIcle SimulatOR (ADVISOR is demonstrated through application examples. Since power electronics is indispensable in hybrid vehicles, the issue of numerical oscillations in dynamic simulations involving power electronics is briefly addressed.

ASPEN Plus simulation of coal integrated gasification combined blast furnace slag waste heat recovery system

International Nuclear Information System (INIS)

Duan, Wenjun; Yu, Qingbo; Wang, Kun; Qin, Qin; Hou, Limin; Yao, Xin; Wu, Tianwei

2015-01-01

Highlights: • An integrated system of coal gasification with slag waste heat recovery was proposed. • The goal of BF slag heat saving and emission reduction was achieved by this system. • The optimal parameters were obtained and the waste heat recovery rate reached 83.08%. • About 6.64 kmol/min syngas was produced when using one ton BF slag to provide energy. - Abstract: This article presented a model for the system of coal gasification with steam and blast furnace slag waste heat recovery by using the ASPEN Plus as the simulating and modeling tool. Constrained by mass and energy balance for the entire system, the model included the gasifier used to product syngas at the chemical equilibrium based on the Gibbs free energy minimization approach and the boiler used to recover the heat of the blast furnace slag (BF slag) and syngas. Two parameters of temperature and steam to coal ratio (S/C) were considered to account for their impacts on the Datong coal (DT coal) gasification process. The carbon gasification efficiency (CE), cold gasification efficiency (CGE), syngas product efficiency (PE) and the heating value of syngas produced by 1 kg pulverized coal (HV) were adopted as the indicators to examine the gasification performance. The optimal operating temperature and S/C were 800 °C and 1.5, respectively. At this condition, CE reached above 90% and the maximum values of the CGE, PE and HV were all obtained. Under the optimal operating conditions, 1000 kg/min BF slag, about 40.41 kg/min DT pulverized coal and 77.94 kg/min steam were fed into the gasifier and approximate 6.64 kmol/min syngas could be generated. Overall, the coal was converted to clean syngas by gasification reaction and the BF slag waste heat was also recovered effectively (reached up to 83.08%) in this system, achieving the objective of energy saving and emission reduction

Electrokinetic acceleration of DNA hybridization in microsystems.

Science.gov (United States)

Lei, Kin Fong; Wang, Yun-Hsiang; Chen, Huai-Yi; Sun, Jia-Hong; Cheng, Ji-Yen

2015-06-01

In this work, electrokinetic acceleration of DNA hybridization was investigated by different combinations of frequencies and amplitudes of actuating electric signals. Because the frequencies from low to high can induce different kinds of electrokinetic forces, i.e., electroosmotic to electrothermal forces, this work provides an in-depth investigation of electrokinetic enhanced hybridization. Concentric circular Cr/Au microelectrodes of 350 µm in diameter were fabricated on a glass substrate and probe DNA was immobilized on the electrode surface. Target DNA labeled with fluorescent dyes suspending in solution was then applied to the electrode. Different electrokinetic forces were induced by the application of different electric signals to the circular microelectrodes. Local microfluidic vortexes were generated to increase the collision efficiency between the target DNA suspending in solution and probe DNA immobilized on the electrode surface. DNA hybridization on the electrode surface could be accelerated by the electrokinetic forces. The level of hybridization was represented by the fluorescent signal intensity ratio. Results revealed that such 5-min dynamic hybridization increased 4.5 fold of signal intensity ratio as compared to a 1-h static hybridization. Moreover, dynamic hybridization was found to have better differentiation ability between specific and non-specific target DNA. This study provides a strategy to accelerate DNA hybridization in microsystems. Copyright © 2015 Elsevier B.V. All rights reserved.

Hybrid Fuel Cell Technology Overview

Energy Technology Data Exchange (ETDEWEB)

None available

2001-05-31

For the purpose of this STI product and unless otherwise stated, hybrid fuel cell systems are power generation systems in which a high temperature fuel cell is combined with another power generating technology. The resulting system exhibits a synergism in which the combination performs with an efficiency far greater than can be provided by either system alone. Hybrid fuel cell designs under development include fuel cell with gas turbine, fuel cell with reciprocating (piston) engine, and designs that combine different fuel cell technologies. Hybrid systems have been extensively analyzed and studied over the past five years by the Department of Energy (DOE), industry, and others. These efforts have revealed that this combination is capable of providing remarkably high efficiencies. This attribute, combined with an inherent low level of pollutant emission, suggests that hybrid systems are likely to serve as the next generation of advanced power generation systems.

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

Science.gov (United States)

LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

2013-01-01

Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

Directory of Open Access Journals (Sweden)

Jared M LeBoldus

Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

Stochastic Reachability Analysis of Hybrid Systems

CERN Document Server

Bujorianu, Luminita Manuela

2012-01-01

Stochastic reachability analysis (SRA) is a method of analyzing the behavior of control systems which mix discrete and continuous dynamics. For probabilistic discrete systems it has been shown to be a practical verification method but for stochastic hybrid systems it can be rather more. As a verification technique SRA can assess the safety and performance of, for example, autonomous systems, robot and aircraft path planning and multi-agent coordination but it can also be used for the adaptive control of such systems. Stochastic Reachability Analysis of Hybrid Systems is a self-contained and accessible introduction to this novel topic in the analysis and development of stochastic hybrid systems. Beginning with the relevant aspects of Markov models and introducing stochastic hybrid systems, the book then moves on to coverage of reachability analysis for stochastic hybrid systems. Following this build up, the core of the text first formally defines the concept of reachability in the stochastic framework and then...

Exotic hybrid mesons in hard electroproduction

CERN Document Server

Anikin, I V; Szymanowski, L; Teryaev, O V; Wallon, S

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic $J^{PC}=1^{-+}$ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e. as $1/Q^2$. This is due to the non-vanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in $\\alpha_{S}$ and we explore the consequences of fixing the renormalization scale ambiguity through the BLM procedure. We study the particular case where the hybrid meson decays through a $\\pi\\eta $ meson pair. We discuss the $\\pi\\eta$ generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of $\\pi$ and $\\eta$ mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very ...

A hybrid mammalian cell cycle model

Directory of Open Access Journals (Sweden)

Vincent Noël

2013-08-01

Full Text Available Hybrid modeling provides an effective solution to cope with multiple time scales dynamics in systems biology. Among the applications of this method, one of the most important is the cell cycle regulation. The machinery of the cell cycle, leading to cell division and proliferation, combines slow growth, spatio-temporal re-organisation of the cell, and rapid changes of regulatory proteins concentrations induced by post-translational modifications. The advancement through the cell cycle comprises a well defined sequence of stages, separated by checkpoint transitions. The combination of continuous and discrete changes justifies hybrid modelling approaches to cell cycle dynamics. We present a piecewise-smooth version of a mammalian cell cycle model, obtained by hybridization from a smooth biochemical model. The approximate hybridization scheme, leading to simplified reaction rates and binary event location functions, is based on learning from a training set of trajectories of the smooth model. We discuss several learning strategies for the parameters of the hybrid model.

Nafion–clay hybrids with a network structure

KAUST Repository

Burgaz, Engin; Lian, Huiqin; Alonso, Rafael Herrera; Estevez, Luis; Kelarakis, Antonios; Giannelis, Emmanuel P.

2009-01-01

Nafion-clay hybrid membranes with a unique microstructure were synthesized using a fundamentally new approach. The new approach is based on depletion aggregation of suspended particles - a well-known phenomenon in colloids. For certain concentrations of clay and polymer, addition of Nafion solution to clay suspensions in water leads to a gel. Using Cryo-TEM we show that the clay particles in the hybrid gels form a network structure with an average cell size in the order of 500 nm. The hybrid gels are subsequently cast to produce hybrid Nafion-clay membranes. Compared to pure Nafion the swelling of the hybrid membranes in water and methanol is dramatically reduced while their selectivity (ratio of conductivity over permeability) increases. The small decrease of ionic conductivity for the hybrid membranes is more than compensated by the large decrease in methanol permeability. Lastly the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion. Both of these characteristics are highly desirable for use in fuel cell applications, since a) they will allow the use of a thinner membrane circumventing problems associated with the membrane resistance and b) enable high temperature applications. © 2009 Elsevier Ltd. All rights reserved.

Sustainability assessment of a hybrid energy system

International Nuclear Information System (INIS)

Afgan, Nain H.; Carvalho, Maria G.

2008-01-01

A hybrid energy system in the form of the Object structure is the pattern for the structure of options in the evaluation of a hybrid system. The Object structure is defined as: Hybrid Energy System {[production (solar, wind, biomass, natural gas)] [utilization(electricity, heat, hydrogen)]}. In the evaluation of hybrid energy systems only several options are selected to demonstrate the sustainability assessment method application in the promotion of the specific quality of the hybrid energy system. In this analysis the following options are taken into a consideration: 1.Solar photo-voltaic power plant (PV PP), wind turbine power plant (WTPP) biomass thermal power plant (ThSTPP) for electricity, heat and hydrogen production. 2.Solar PV PP and wind power plant (WPP) for electricity and hydrogen production. 3.Biomass thermal steam turbine power plant (BThSTPP) and WPP for heat and hydrogen production. 4.Combined cycle gas turbine power plant for electricity and hydrogen production. 5.Cogeneration of electricity and water by the hybrid system. The sustainability assessment method is used for the evaluation of quality of the selected hybrid systems. In this evaluation the following indicators are used: economic indicator, environment indicator and social indicator

Nafion–clay hybrids with a network structure

KAUST Repository

Burgaz, Engin

2009-05-01

Nafion-clay hybrid membranes with a unique microstructure were synthesized using a fundamentally new approach. The new approach is based on depletion aggregation of suspended particles - a well-known phenomenon in colloids. For certain concentrations of clay and polymer, addition of Nafion solution to clay suspensions in water leads to a gel. Using Cryo-TEM we show that the clay particles in the hybrid gels form a network structure with an average cell size in the order of 500 nm. The hybrid gels are subsequently cast to produce hybrid Nafion-clay membranes. Compared to pure Nafion the swelling of the hybrid membranes in water and methanol is dramatically reduced while their selectivity (ratio of conductivity over permeability) increases. The small decrease of ionic conductivity for the hybrid membranes is more than compensated by the large decrease in methanol permeability. Lastly the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion. Both of these characteristics are highly desirable for use in fuel cell applications, since a) they will allow the use of a thinner membrane circumventing problems associated with the membrane resistance and b) enable high temperature applications. © 2009 Elsevier Ltd. All rights reserved.

Deep electroproduction of exotic hybrid mesons

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2004-01-01

We evaluate the leading order amplitude for the deep exclusive electroproduction of an exotic hybrid meson in the Bjorken regime. We show that, contrarily to naive expectation, this amplitude factorizes at the twist 2 level and thus scales like usual meson electroproduction when the virtual photon and the hybrid meson are longitudinally polarized. Exotic hybrid mesons may thus be studied in electroproduction experiments at JLAB, HERA (HERMES) or CERN (Compass)

Hybrid magnets at Tohoku University

International Nuclear Information System (INIS)

Muto, Yoshio; Nakagawa, Yasuaki; Noto, Koshichi; Hoshi, Akira; Miura, Shigeto; Watanabe, Kazuo; Kido, Giyuu

1984-01-01

The High Field Laboratory for Superconducting Materials was established in April 1981 at Tohoku University in order to provide research facilities for the development of superconducting materials suitable for superconducting magnets for the plasma confinement in fusion reactors. Main facilities of this laboratory are three hybrid magnets up to 30 Tesla dc magnetic fields with inner bores from 32 to 52mm in diameter. The magnets consist of superconducting outer solenoids and water-cooled inner ones with a maximum steady power dissipation of 8 MW. The design and construction of these three hybrid magnets have finished in last three years, and two of them (HM-3;20T, 32 mm bore and HM-2; 23T, 52 mm bore) have already opened to scientists and engineers in the superconductivity and other fields. The rated field of the third hybrid magnet (HM-1) is 31 (or 29) Tesla in a bore of 32 (or 52) mm in diameter. By this hybrid system we have succeeded to produce 29.3 Tesla on April 21, 1984. Detailed descriptions are presented on the superconducting magnets, power supplies and cooling systems for them, water-cooled magnets, dc-high power source and water-cooled system for them, the monitoring and control system for the hybrid magnets including a super-minicomputer system, a hard-wired interlock system for the safety of human beings and machines, and so on. The fourth hybrid magnet system which aims at 35 Tesla as the next phase is also discussed. (author)

Electric and Hybrid Vehicle System Research and Development Project: Hybrid Vehicle Potential Assessment. Volume VI. Cost analysis

Energy Technology Data Exchange (ETDEWEB)

Hardy, K.S.

1979-09-30

The purpose of the cost analysis is to determine the economic feasibility of a variety of hybrid vehicles with respect to conventional vehicles specifically designed for the same duty cycle defined by the mission analysis. Several different hybrid configurations including parallel, parallel-flywheel, and series vehicles were evaluated. The ramifications of incorporating examples of advanced batteries, these being the advanced lead-acid, nickel-zinc, and sodium sulfur were also investigated. Vehicles were specifically designed with these batteries and for the driving cycles specified by the mission. Simulated operation on the missions yielded the energy consumption (petroleum and/or electricity) over the driving cycles. It was concluded that: in the event that gasoline prices reach $2.50 to $3.00/gal, hybrid vehicles in many applications will become economically competitive with conventional vehicles without subsidization; in some commercial applications hybrid vehicles could be economically competitive, when the gasoline price ranges from $1.20 to $1.50/gal. The cost per kWh per cycle of the advanced batteries is much more important economically than the specific energy; the series hybrid vehicles were found to be more expensive in comparison to the parallel or parallel-flywheel hybrids when designed as passenger vehicles; and hybrid vehicles designed for private use could become economically competitive and displace up to 50% of the fuel normally used on that mission if subsidies of $500 to $2000 were supplied to the owner/operator. (LCL)

Constructing decidable hybrid systems with velocity bounds

NARCIS (Netherlands)

Belta, C.; Habets, L.C.G.J.M.

2004-01-01

In this paper, the question of bi-similarity between hybrid systems and their discrete quotients is studied from a new point of view. We consider two classes of hybrid systems: piecewise affine hybrid systems on simplices and piecewise multi-affine systems on multi-dimensional rectangles. Given a

Agronomic and chemical characteristics of hybrid corn to ensiling

Directory of Open Access Journals (Sweden)

Flávia Borges de Assis

2014-12-01

Full Text Available Our aim was to evaluate agronomic and chemical characteristics of corn hybrids to ensiling. It were evaluated nine corn hybrids (MX 300, RB 9308, 2B655, XB 6012, GNZ 2500, PL6890, PRE 32D10, PRE 22T10 e AG 1051, with three replicates. The higher fresh matter yield were observed in the hybrids PL6890 and PRE 32D10, while the dry matter yield was observed in the hybrid PRE 32D10 (13.43 t ha-1. The hybrids PRE 32D10 and PRE 22T10 stood out to present higher percent of leaf in relation to whole plant, while the lower percent of stems was found in the hybrids MX 300, 2B655 and XB 6012, however the higher leaves: stems relation was found in XB 6012 (0.49. There was higher CP content in the hybrid PRE 32D10 (9.10% of DM, while the lower NDF (57.78% of DM and cellulose content (24.27% of DM were observed in the hybrid GNZ 2500. The hybrid PL6890 presented higher ADF and lignin contents, the others hybrids had values lower. The lower NDIN content was observed in the hybrid RB 9308, while the lower AIDN content occurred on the hybrid 2B655. The lower buffer capacity was observed in the hybrid 2B655 (0.29. There are some differences on chemical composition among the corn hybrids used in this study, however, it is recommended to use the hybrids MX 300, PL6890 and PRE 32D10 for showing higher dry matter yield, which may reflect in the amortization of silage production costs.

The hybrid electric vehicle revolution, off road

Energy Technology Data Exchange (ETDEWEB)

Wood, B.E. [ePower Technologies (United States)

2004-07-01

In this presentation the author presents concepts and details of hybrid vehicles in general, including their benefits, then describes off-road hybrid vehicles. Hybrid vehicles have been experimented with for over a century. Demonstrator vehicles include a diesel-electric tractor, an electric lawn tractor, a hybrid snow thrower, and a hybrid wheel loader. A duty cycle for the loader is shown with battery-assisted acceleration, and regenerative braking. Both of these keep the size of the engine small, the loads on it less variable, thus improving fuel economy. A hybrid excavator and its duty cycle is shown. A fuel cell lift truck that is currently in design is illustrated. The author then describes the possibilities of the hydrogen economy where sourcing and infrastructure are yet to be demonstrated on a commercial scale. The author predicts that off-road hydrogen fuel cell vehicles will be commercially viable five years before on-road applications. The author predicts hydrogen sourced from biogas, photovoltaics, and wind power. tabs, figs.

The governance of hybrid organisations

DEFF Research Database (Denmark)

Spear, Roger; Cornforth, Chris

2010-01-01

The focus of this chapter is on the governance of third sector organizations (TSOs) and the challenges that are raised by hybridity. In particular it will focus on the question how does hybridity affect governance structures and processes and the challenges that governing bodies face?...

Research of a hybrid undulator

International Nuclear Information System (INIS)

Ma Youwu; Wu Bing; Liu Bo

1995-12-01

A 1.5 m tapered hybrid undulator has been designed and built for mid-infrared free electron laser experiments at CIAE. The undulator utilizes the REC-steel hybrid configuration. The magnetic gap and magnetic field taper can be continuously adjusted. The rms error of the peak field is less than 0.53%. The electron trajectory deviation is around 0.03 mm. The design of undulator, sorting of magnets in hybrid undulator using simulated annealing technique, the motion of electron beam in the ideal and measured magnetic field, magnetic field measurement technique and magnetic field adjustment are described. (6 refs., 10 figs., 1 tab)

Hybrid keyword search auctions

KAUST Repository

Goel, Ashish

2009-01-01

Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer\\'s estimate can use per-impression bids to correct the auctioneer\\'s prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The

Hybrid keyword search auctions

KAUST Repository

Goel, Ashish; Munagala, Kamesh

2009-01-01

Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer's estimate can use per-impression bids to correct the auctioneer's prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The hybrid

Exotic hybrid mesons in hard electroproduction

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic J PC =1 -+ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e., as 1/Q 2 . This is due to the nonvanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy-momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in α S and we explore the consequences of fixing the renormalization scale ambiguity through the Brodsky-Lepage-Mackenzie (BLM) procedure. We study the particular case where the hybrid meson decays through a πη meson pair. We discuss the πη generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of π and η mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very high energy, in the diffractive limit where a QCD Odderon exchange mechanism should dominate. The conclusion of our study is that hard electroproduction is a promising way to study exotic hybrid mesons, in particular, at JLAB, HERA (HERMES), or CERN (Compass)

Hybrid strategies in nanolithography

Energy Technology Data Exchange (ETDEWEB)

Saavedra, Hector M; Mullen, Thomas J; Zhang Pengpeng; Dewey, Daniel C; Claridge, Shelley A; Weiss, Paul S [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States)], E-mail: psw@cnsi.ucla.edu

2010-03-15

Hybrid nanoscale patterning strategies combine the registration and addressability of conventional lithographic techniques with the chemical and physical functionality enabled by intermolecular, electrostatic and/or biological interactions. This review aims to highlight and to provide a comprehensive description of recent developments in hybrid nanoscale patterning strategies that enhance existing lithographic techniques or can be used to fabricate functional chemical patterns that interact with their environment. These functional structures create new capabilities, such as the fabrication of physicochemical surfaces that can recognize and capture analytes from complex liquid or gaseous mixtures. The nanolithographic techniques we describe can be classified into three general areas: traditional lithography, soft lithography and scanning-probe lithography. The strengths and limitations of each hybrid patterning technique will be discussed, along with the current and potential applications of the resulting patterned, functional surfaces.

The Hybrid Automobile and the Atkinson Cycle

Science.gov (United States)

Feldman, Bernard J.

2008-01-01

The hybrid automobile is a strikingly new automobile technology with a number of new technological features that dramatically improve energy efficiency. This paper will briefly describe how hybrid automobiles work; what are these new technological features; why the Toyota Prius hybrid internal combustion engine operates on the Atkinson cycle…

Hybrid Logical Analyses of the Ambient Calculus

DEFF Research Database (Denmark)

Bolander, Thomas; Hansen, Rene Rydhof

2010-01-01

In this paper, hybrid logic is used to formulate three control flow analyses for Mobile Ambients, a process calculus designed for modelling mobility. We show that hybrid logic is very well-suited to express the semantic structure of the ambient calculus and how features of hybrid logic can...

Energy from poultry waste: An Aspen Plus-based approach to the thermo-chemical processes.

Science.gov (United States)

Cavalaglio, Gianluca; Coccia, Valentina; Cotana, Franco; Gelosia, Mattia; Nicolini, Andrea; Petrozzi, Alessandro

2018-03-01

A particular approach to the task of energy conversion of a residual waste material was properly experienced during the implementation of the national funded Enerpoll project. This project is a case study developed in the estate of a poultry farm that is located in a rural area of central Italy (Umbria Region); such a farm was chosen for the research project since it is almost representative of many similar small-sized breeding realties of the Italian regional context. The purpose of the case study was the disposal of a waste material (i.e. poultry manure) and its energy recovery; this task is in agreement with the main objectives of the new Energy Union policy. Considering this background, an innovative gasification plant (300KW thermal power) was chosen and installed for the experimentation. The novelty of the investigated technology is the possibility to achieve the production of thermal energy burning just the produced syngas and not directly the solid residues. This aspect allows to reduce the quantity of nitrogen released in the atmosphere by the exhaust flue gases and conveying it into the solid residues (ashes). A critical aspect of the research program was the optimization of the pretreatment (reduction of the water content) and the dimensional homogenization of the poultry waste before its energy recovery. This physical pretreatment allowed the reduction of the complexity of the matrix to be energy enhanced. Further to the real scale plant monitoring, a complete Aspen Plus v.8.0 model was also elaborated for the prediction of the quality of the produced synthesis gas as a function of both the gasification temperature and the equivalence ratio (ER). The model is an ideal flowchart using as input material just the homogenized and dried material. On the basis of the real monitored thermal power (equal to about 200kW average value in an hour) the model was used for the estimation of the syngas energy content (i.e. LHV) that resulted in the range of 3-5MJ/m 3