WorldWideScience

Sample records for aspen model development

  1. 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.

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

    Institute of Scientific and Technical Information of China (English)

    单贤根; 常小瑞; 任琼; 江洪波; 翁惠新

    2014-01-01

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

  3. A flexible model for biomass fast pyrolysis in Aspen+

    OpenAIRE

    Kohl, Thomas; Laukkanen, Timo; Järvinen, Mika

    2012-01-01

    In order to estimate the heat of condensation of fast pyrolysis product of woody biomass a model to be used in the chemical process simulation software Aspen+ has been developed based on the composition of wood fast pyrolysis product. A simulation model for biomass fast pyrolysis was developed. The results obtained are in good accordance with values found in the literature. With more specific data (e.g. from measurements) it should be possible to adjust the flexible model to other data. ...

  4. Coal conversion systems design and process modeling. Volume 1: Application of MPPR and Aspen computer models

    Science.gov (United States)

    1981-01-01

    The development of a coal gasification system design and mass and energy balance simulation program for the TVA and other similar facilities is described. The materials-process-product model (MPPM) and the advanced system for process engineering (ASPEN) computer program were selected from available steady state and dynamic models. The MPPM was selected to serve as the basis for development of system level design model structure because it provided the capability for process block material and energy balance and high-level systems sizing and costing. The ASPEN simulation serves as the basis for assessing detailed component models for the system design modeling program. The ASPEN components were analyzed to identify particular process blocks and data packages (physical properties) which could be extracted and used in the system design modeling program. While ASPEN physical properties calculation routines are capable of generating physical properties required for process simulation, not all required physical property data are available, and must be user-entered.

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

    Institute of Scientific and Technical Information of China (English)

    吴建方

    2011-01-01

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

  6. 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.

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

    International Nuclear Information System (INIS)

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

  8. Tank SY-102 remediation project summary report: ASPEN modeling

    International Nuclear Information System (INIS)

    The U.S. Department of Energy established the Tank Waste Remediation System (TWRS) to safely manage and dispose of radioactive waste stored in underground tanks on the Hanford Site. As a part of this program, personnel at Los Alamos National Laboratory (LANL) have developed and demonstrated a flow sheet to remediate tank SY-102, which is located in the 200 West Area and contains high-level radioactive waste. In the conceptual design report issued earlier, an ASPEN plus trademark computer model of the flow sheet was presented. This report documents improvements in the flow sheet model after additional thermodynamic data for the actinide species were incorporated

  9. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Tord Johansson

    2013-01-01

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

  11. 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...

  12. Modeling water/lithium bromide absorption chillers in ASPEN Plus

    International Nuclear Information System (INIS)

    Highlights: → Single- and double-effect water/lithium bromide absorption chiller designs are numerically modeled using ASPEN. → The modeling procedure is described and the results are compared to published modeling data to access prediction accuracy. → Predictions for the single- and double-effect designs are within 3% and 5%, respectively of published data for all cycle parameters of interest. → The absorption cycle models presented allow investigation of using absorption chillers for waste heat utilization in the oil and gas industry. -- Abstract: Absorption chillers are a viable option for providing waste heat-powered cooling or refrigeration in oil and gas processing plants, thereby improving energy efficiency. In this paper, single- and double-effect water/lithium bromide absorption chiller designs are numerically modeled using ASPEN. The modeling procedure is described and the results are compared to published modeling data to access prediction accuracy. Predictions for the single- and double-effect designs are within 3% and 5%, respectively of published data for all cycle parameters of interest. The absorption cycle models presented not only allow investigation into the benefits of using absorption chillers for waste heat utilization in the oil and gas industry, but are also generically applicable to a wide range of other applications.

  13. 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

    settings and correlated aspen functional types. We propose the following aspen fire regime types: (1) fire-independent, stable aspen; (2) fire-influenced, stable aspen; (3) fire-dependent, seral, conifer-aspen mix; (4) fire-dependent, seral, montane aspen-conifer; and (5) fire-dependent, seral, subalpine aspen-conifer. Closing research gaps and validating our proposed aspen fire regime classification will likely require additional site-specific research, enhanced dendrochronology techniques, charcoal and pollen record analysis, spatially-explicit modeling, and other techniques. We hope to encourage development of site-appropriate disturbance ecology characterizations, in order to aid efforts to manage and restore aspen communities and to diagnose key factors contributing to changes in aspen.

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

    International Nuclear Information System (INIS)

    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 AspenPlusTM, 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 AspenPlusTM 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 AspenPlusTM functions and existing unit operation modules. The developed ''AspenPlusTM 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 (Uf), current density (Ic) and steam-carbon ratio (S/C), were performed using the developed model, and the results are discussed in this paper

  15. 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.

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

    Institute of Scientific and Technical Information of China (English)

    原璐; 吕海霞; 项曙光

    2005-01-01

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

  17. Three Stage Equilibrium Model for Coal Gasification in Entrained Flow Gasifiers Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    KONG Xiangdong; ZHONG Weimin; DU Wenli; QIAN Feng

    2013-01-01

    A three stage equilibrium model is developed for coal gasification in the Texaco type coal gasifiers based on Aspen Plus to calculate the composition of product gas,carbon conversion,and gasification temperature.The model is divided into three stages including pyrolysis and combustion stage,char gas reaction stage,and gas phase reaction stage.Part of the water produced in the pyrolysis and combustion stage is assumed to be involved in the second stage to react with the unburned carbon.Carbon conversion is then estimated in the second stage by steam participation ratio expressed as a function of temperature.And the gas product compositions are calculated from gas phase reactions in the third stage.The simulation results are consistent with published experimental data.

  18. Integrated model of G189A and Aspen-plus for the transient modeling of extravehicular activity atmospheric control systems

    Science.gov (United States)

    Kolodney, Matthew; Conger, Bruce C.

    1990-01-01

    A computerized modeling tool, under development for the transient modeling of an extravehicular activity atmospheric control subsystem is described. This subsystem includes the astronaut, temperature control, moisture control, CO2 removal, and oxygen make-up components. Trade studies evaluating competing components and subsystems to guide the selection and development of hardware for lunar and Martian missions will use this modeling tool. The integrated modeling tool uses the Advanced System for Process Engineering (ASPEN) to accomplish pseudosteady-state simulations, and the general environmental thermal control and life support program (G189A) to manage overall control of the run and transient input output, as well as transient modeling computations and database functions. Flow charts and flow diagrams are included.

  19. Aspen Delineation - Aspen Delineation Project [ds362

    Data.gov (United States)

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

  20. 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.

  1. A novel process simulation model (PSM) for anaerobic digestion using Aspen Plus.

    Science.gov (United States)

    Rajendran, Karthik; Kankanala, Harshavardhan R; Lundin, Magnus; Taherzadeh, Mohammad J

    2014-09-01

    A novel process simulation model (PSM) was developed for biogas production in anaerobic digesters using Aspen Plus®. The PSM is a library model of anaerobic digestion, which predicts the biogas production from any substrate at any given process condition. A total of 46 reactions were used in the model, which include inhibitions, rate-kinetics, pH, ammonia, volume, loading rate, and retention time. The hydrolysis reactions were based on the extent of the reaction, while the acidogenic, acetogenic, and methanogenic reactions were based on the kinetics. The PSM was validated against a variety of lab and industrial data on anaerobic digestion. The P-value after statistical analysis was found to be 0.701, which showed that there was no significant difference between discrete validations and processing conditions. The sensitivity analysis for a ±10% change in composition of substrate and extent of reaction results in 5.285% higher value than the experimental value. The model is available at http://hdl.handle.net/2320/12358 (Rajendran et al., 2013b).

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

    Science.gov (United States)

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

    2016-08-01

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

  3. 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. PMID:27317615

  4. Modeling and optimization of a regenerative fuel cell system using the ASPEN process simulator

    Science.gov (United States)

    Maloney, Thomas M.; Leibecki, Harold F.

    1990-01-01

    The Hydrogen-Oxygen Regenerative Fuel Cell System was identified as a key component for energy storage in support of future lunar missions. Since the H2-O2 regenerative electrochemical conversion technology has not yet been tested in space applications, it is necessary to implement predictive techniques to develop initial feasible system designs. The ASPEN simulation software furnishes a constructive medium for analyzing and optimizing such systems. A rudimentary regenerative fuel cell system design was examined using the ASPEN simulator and this modular approach allows for easy addition of supplementary ancillary components and easy integration with life support systems. The modules included in the preliminary analyses may serve as the fundamental structure for more complicated energy storage systems.

  5. On the modeling of a single-stage, entrained-flow gasifier using Aspen Custom Modeler (ACM)

    Energy Technology Data Exchange (ETDEWEB)

    Kasule, J.; Turton, R.; Bhattacharyya, D.; Zitney, S.

    2010-01-01

    Coal-fired gasifiers are the centerpiece of integrated gasification combined cycle (IGCC) power plants. The gasifier produces synthesis gas that is subsequently converted into electricity through combustion in a gas turbine. Several mathematical models have been developed to study the physical and chemical processes taking place inside the gasifier. Such models range from simple one-dimensional (1D) steady-state models to sophisticated dynamic 3D computational fluid dynamics (CFD) models that incorporate turbulence effects in the reactor. The practical operation of the gasifier is dynamic in nature but most 1D and some higher-dimensional models are often steady state. On the other hand, many higher order CFD-based models are dynamic in nature, but are too computationally expensive to be used directly in operability and controllability dynamic studies. They are also difficult to incorporate in the framework of process simulation software such as Aspen Plus Dynamics. Thus lower-dimensional dynamic models are still useful in these types of studies. In the current study, a 1D dynamic model for a single-stage, downward-firing, entrained-flow GE-type gasifier is developed using Aspen Custom Modeler{reg_sign} (ACM), which is a commercial equation-based simulator for creating, editing, and re-using models of process units. The gasifier model is based on mass, momentum, and energy balances for the solid and gas phases. The physical and chemical reactions considered in the model are drying, devolatilization/pyrolysis, gasification, combustion, and the homogeneous gas phase reactions. The dynamic gasifier model is being developed for use in a plant-wide dynamic model of an IGCC power plant. For dynamic simulation, the resulting highly nonlinear system of partial differential algebraic equations (PDAE) is solved in ACM using the well-known Method of Lines (MoL) approach. The MoL discretizes the space domain and leaves the time domain continuous, thereby converting the PDAE to

  6. 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.

  7. Aspen Trees.

    Science.gov (United States)

    Canfield, Elaine

    2002-01-01

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

  8. From the Aspen File.

    Science.gov (United States)

    Aspen Institute Quarterly, 1993

    1993-01-01

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

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

    International Nuclear Information System (INIS)

    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

  10. Global modeling of Hanford tank waste pretreatment alternatives within a total cleanup system using ASPEN PLUS{trademark}

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, B.J.; Jansen, G. Jr.; Zimmerman, B.D.; Niccoli, L.G. [Westinghouse Hanford Co., Richland, WA (United States); Lauerhass, L. [Pacific Northwest Lab., Richland, WA (United States)

    1994-11-01

    The purpose of this work is to evaluate and compare radionuclide separations/processing technologies being developed or considered as Hanford tank waste pretreatment alternatives. These technologies are integrated into a total cleanup system that includes tank waste retrieval, treatment, and disposal. Current Hanford flowsheets typically include only mature, developed technologies, not new technologies. Thus, this work examines the impact/benefits of inserting new technologies into Hanford flowsheets. Waste treatment must produce disposal fractions which are less troublesome than the original material. Researchers seeking effective treatment methods may lack the tools or expertise to fully understand the implications of their approach in terms of secondary and tertiary waste streams or the extent to which a unique new process will affect upstream or downstream processes. This work has developed and demonstrated mass balance methods that clarify the effect of including individual processes in an integrated waste treatment system, such as the Hanford cleanup system. The methods provide a measure of treatment effectiveness and a format for the researcher to understand waste stream interrelationships and determine how a particular treatment technology can best be used in a cleanup system. A description of the Hanford tank waste cleanup model developed using the ASPEN PLUS flowsheet simulation tool is given. Important aspects of the modeling approach are discussed along with a description of how performance measures were developed and integrated within the simulation to evaluate and compare various Hanford tank waste pretreatment alternatives.

  11. Global modeling of Hanford tank waste pretreatment alternatives within a total cleanup system using ASPEN PLUS trademark

    International Nuclear Information System (INIS)

    The purpose of this work is to evaluate and compare radionuclide separations/processing technologies being developed or considered as Hanford tank waste pretreatment alternatives. These technologies are integrated into a total cleanup system that includes tank waste retrieval, treatment, and disposal. Current Hanford flowsheets typically include only mature, developed technologies, not new technologies. Thus, this work examines the impact/benefits of inserting new technologies into Hanford flowsheets. Waste treatment must produce disposal fractions which are less troublesome than the original material. Researchers seeking effective treatment methods may lack the tools or expertise to fully understand the implications of their approach in terms of secondary and tertiary waste streams or the extent to which a unique new process will affect upstream or downstream processes. This work has developed and demonstrated mass balance methods that clarify the effect of including individual processes in an integrated waste treatment system, such as the Hanford cleanup system. The methods provide a measure of treatment effectiveness and a format for the researcher to understand waste stream interrelationships and determine how a particular treatment technology can best be used in a cleanup system. A description of the Hanford tank waste cleanup model developed using the ASPEN PLUS flowsheet simulation tool is given. Important aspects of the modeling approach are discussed along with a description of how performance measures were developed and integrated within the simulation to evaluate and compare various Hanford tank waste pretreatment alternatives

  12. Comparative simulation study of gas-phase propylene polymerization in fluidized bed reactors using aspen polymers and two phase models

    Directory of Open Access Journals (Sweden)

    Shamiria Ahmad

    2013-01-01

    Full Text Available A comparative study describing gas-phase propylene polymerization in fluidized-bed reactors using Ziegler-Natta catalyst is presented. The reactor behavior was explained using a two-phase model (which is based on principles of fluidization as well as simulation using the Aspen Polymers process simulator. The two-phase reactor model accounts for the emulsion and bubble phases which contain different portions of catalysts with the polymerization occurring in both phases. Both models predict production rate, molecular weight, polydispersity index (PDI and melt flow index (MFI of the polymer. We used both models to investigate the effect of important polymerization parameters, namely catalyst feed rate and hydrogen concentration, on the product polypropylene properties, such as production rate, molecular weight, PDI and MFI. Both the two-phase model and Aspen Polymers simulator showed good agreement in terms of production rate. However, the models differed in their predictions for weight-average molecular weight, PDI and MFI. Based on these results, we propose incorporating the missing hydrodynamic effects into Aspen Polymers to provide a more realistic understanding of the phenomena encountered in fluidized bed reactors for polyolefin production.

  13. The incorporation of an organic soil layer in the Noah-MP Land Surface Model and its evaluation over a Boreal Aspen Forest

    OpenAIRE

    Chen, L.; Li, Y.; Chen, F.; Barr, A.; Barlage, M.; Wan, B

    2015-01-01

    In this study, the multi-parameterization version of the Noah land-surface model (Noah-MP) was used to investigate the impact of adding a forest-floor organic soil layer on the simulated surface energy and water cycle components at a boreal aspen forest. The test site selected is BERMS Old Aspen Flux (OAS) field station in central Saskatchewan, Canada. The selection of different parameterization schemes for each process within the current Noah-MP model significantly affected...

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

    OpenAIRE

    Javier Fontalvo Alzate

    2014-01-01

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

  15. Automated Design Space Exploration with Aspen

    Directory of Open Access Journals (Sweden)

    Kyle L. Spafford

    2015-01-01

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

  16. Aspen Characteristics - Aspen Delineation Project [ds361

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2014-01-01

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

  18. 工业级催化重整装置的全流程模拟与优化%Modeling, Simulation and Optimization of a Whole Industrial Catalytic Naphtha Reforming Process on Aspen Plus Platform

    Institute of Scientific and Technical Information of China (English)

    侯卫锋; 苏宏业; 胡永有; 褚健

    2006-01-01

    A new 18-lump kinetic model for naphtha catalytic reforming reactions is discussed. By developing this model as a user module, a whole industrial continuous catalytic reforming process is simulated on Aspen plus plat form. The technique utilizes the strong databases, complete sets of modules, and flexible simulation tools of the Aspen plus system and retains the characteristics of the proposed kinetic model. The calculated results are in fair agreement with the actual operating data. Based on the model of the whole reforming process, the process is optimized and the optimization results are tested in the actual industrial unit for about two months. The test shows that the process profit increases about 1000yuan·h-1 averagely, which is close to the calculated result.

  19. 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.

  20. 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.

  1. Aspen Notebook: Cable and Continuing Education.

    Science.gov (United States)

    Adler, Richard; Baer, Walter S.

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

  2. Development of a Real-Time Expert Diagnostic and Supervision System for Flow Corrosion Condition Based on Aspen Plus Technology%基于Aspen Plus技术的流动腐蚀实时专家诊断监管系统开发

    Institute of Scientific and Technical Information of China (English)

    叶伊莎; 任佳; 偶国富; 程宏伟; 吴学华; 金浩哲

    2016-01-01

    针对石化企业炼油系统流动腐蚀失效频繁发生的现状、结合现场系统可靠性和安全性的需求,在企业现有信息化管理系统基础上,设计并开发了基于Aspen Plus技术的流动腐蚀实时专家诊断监管系统.该系统采用面向对象的设计原则,以.NET为开发平台和MySQL为数据后台,采用Visual Basic(VB)的ActiveX技术与Aspen Plus工艺仿真模型连接,结合Windows Communication Foundation(WCF)与.Net Remoting通信技术进行数据通讯.该系统框架可应用于多种炼油系统腐蚀监控平台的开发,以此框架开发了常压塔顶实时流动腐蚀监控平台,该监管平台能够实现装置数据的动态监测、历史数据查询、超限报警和措施指导等功能,具有有效的腐蚀防控作用.%Aiming at decreasing the flow corrosion failure happened frequently in refining system, considering the requirements of onsite system reliability and security, on the basis of enterprise’s existing information system, a real-time expert diagnostic and supervision system for flow corrosion condition based on Aspen Plus technology is developed. The system uses object-oriented design principles, with .NET as the development platform and MySQL as the backend database. Using the ActiveX technology of Visual Basic (VB), and Aspen Plus, process simulation model is connected with the system. Windows Communication Foundation (WCF) and .Net Remoting techniques are used for data communication. This structure given previously can be applied to a variety of oil refining systems. An application instance in atmospheric overhead system has been developed, which can achieve the dynamic data monitoring, the query of historical data, guidance and measures of limiting alarm, with effective function in corrosion prevention and control.

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

    Directory of Open Access Journals (Sweden)

    Javier Fontalvo Alzate

    2014-07-01

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

  4. Aspen Process Flowsheet Simulation Model of a Battelle Biomass-Based Gasification, Fischer-Tropsch Liquefaction and Combined-Cycle Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-10-30

    This study was done to support the research and development program of the National Renewable Energy Laboratory (NREL) in the thermochemical conversion of biomass to liquid transportation fuels using current state-of-the-art technology. The Mitretek study investigated the use of two biomass gasifiers; the RENUGAS gasifier being developed by the Institute of Gas Technology, and the indirectly heated gasifier being developed by Battelle Columbus. The Battelle Memorial Institute of Columbus, Ohio indirectly heated biomass gasifier was selected for this model development because the syngas produced by it is better suited for Fischer-Tropsch synthesis with an iron-based catalyst for which a large amount of experimental data are available. Bechtel with Amoco as a subcontractor developed a conceptual baseline design and several alternative designs for indirect coal liquefaction facilities. In addition, ASPEN Plus process flowsheet simulation models were developed for each of designs. These models were used to perform several parametric studies to investigate various alternatives for improving the economics of indirect coal liquefaction.

  5. The incorporation of an organic soil layer in the Noah-MP land surface model and its evaluation over a boreal aspen forest

    OpenAIRE

    Chen, Liang; Li, Yanping; Chen, Fei; Barr, Alan; Barlage, Michael; Wan, Bingcheng

    2016-01-01

    A thick top layer of organic matter is a dominant feature in boreal forests and can impact land–atmosphere interactions. In this study, the multi-parameterization version of the Noah land surface model (Noah-MP) was used to investigate the impact of incorporating a forest-floor organic soil layer on the simulated surface energy and water cycle components at the BERMS Old Aspen site (OAS) field station in central Saskatchewan, Canada. Compared to a simulation without an organ...

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

    Science.gov (United States)

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

    2004-01-01

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

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

    Science.gov (United States)

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

    2004-05-01

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

  8. 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.

  9. 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.

  10. 基于Aspen Plus软件的循环流化床烟气脱硫模型%A model of flue gas desulfurization for circulating fluidized bed using Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    颜湘华; 朱廷钰; 王威; 何京东

    2009-01-01

    Model study and flow simulation of circulating fluidized bed flue gas desulfurization (CFB-FGD) were described in this pa-per. The mathematic model of flue gas desulfurization for circulating fluidized bed (CFB) was buih on the basis of element analysis for mass transfer of SO2. The enhancement of the desulfurization reaction in the process of mass transfer of SO2 was analyzed with the doub-le-membrane theory in the model. And the real formation process of slurry droplet was accounted with the theory of inertia collision. And then a simulation study of CFB-FGD was conducted based on Aspen Plus, where a module subroutine was programmed in FOR-TRAN based on this model. The influences of the key parameters such as calcium-to-sulfur ration (Ca/S), flux of spay water, concen-tration of sorbent particles and water drop size on the desulfurization efficiency were analyzed. The modeling results were compared with the experimental data and the comparing results showed that this model could preferably predict the real trends, This paper would help the application of CFB-FGD as references.%本文研究和模拟循环流化床烟气脱硫的流程和模型.以微元分析SO2的传质为基础,建立循环流化床烟气脱硫的数学模型,模型用双膜理论分析脱硫反应对SO2传质过程的增强影响,并采用惯性碰撞理论解释浆滴的形成过程.借助Aspen Plus过程模拟平台,用FORTRAN语言编写基于该模型的用户单元模块,模拟循环流化床烟气脱硫工艺,分析Ca/S、增湿水量、塔内颗粒物浓度、水滴粒径等参数对脱硫的影响,模拟计算结果和实验数据的对比显示模型能如实反映实际的趋势.本文为应用循环流化床烟气脱硫技术提供参考.

  11. ASPEN Plus Simulation of CO2 Recovery Process

    Energy Technology Data Exchange (ETDEWEB)

    Charles W. White III

    2003-09-30

    ASPEN Plus simulations have been created for a CO{sub 2} capture process based on adsorption by monoethanolamine (MEA). Three separate simulations were developed, one each for the flue gas scrubbing, recovery, and purification sections of the process. Although intended to work together, each simulation can be used and executed independently. The simulations were designed as template simulations to be added as a component to other more complex simulations. Applications involving simple cycle or hybrid power production processes were targeted. The default block parameters were developed based on a feed stream of raw flue gas of approximately 14 volume percent CO{sub 2} with a 90% recovery of the CO{sub 2} as liquid. This report presents detailed descriptions of the process sections as well as technical documentation for the ASPEN simulations including the design basis, models employed, key assumptions, design parameters, convergence algorithms, and calculated outputs.

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

    Science.gov (United States)

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

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

  13. Aspen Code Development Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    none,; Cherry, Robert S. [INL; Richard, Boardman D. [INL

    2013-10-03

    Wyoming has a wealth of primary energy resources in the forms of coal, natural gas, wind, uranium, and oil shale. Most of Wyoming?s coal and gas resources are exported from the state in unprocessed form rather than as refined higher value products. Wyoming?s leadership recognizes the opportunity to broaden the state?s economic base energy resources to make value-added products such as synthetic vehicle fuels and commodity chemicals. Producing these higher value products in an environmentally responsible manner can benefit from the use of clean energy technologies including Wyoming?s abundant wind energy and nuclear energy such as new generation small modular reactors including the high temperature gas-cooled reactors.

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

    Directory of Open Access Journals (Sweden)

    Sara Alian

    2015-05-01

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

  15. Experiential Education at Aspen High School.

    Science.gov (United States)

    Burson, George

    1981-01-01

    Aspen High School's (Colorado) Experiential Education Week, developed to provide a "real-world" experience for students from a small, mountain, tourist-oriented community, is planned by both student and faculty; the whole process encourages both self-reliant and responsible students and develops positive student-teacher and peer relationships.…

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

    Science.gov (United States)

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

    2016-05-01

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

  17. Aspen Delineation - Klamath National Forest [ds370

    Data.gov (United States)

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

  18. Aspen Delineation - Inyo National Forest [ds366

    Data.gov (United States)

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

  19. THE ASPEN CONTINUOUS PROGRESS PLAN.

    Science.gov (United States)

    MORNINGSTAR, NED

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

  20. 77 FR 60119 - Proposed Consent Agreements: DesignerWare, LLC, Timothy Kelly and Ronald P. Koller, Aspen Way...

    Science.gov (United States)

    2012-10-02

    ... Proposed Consent Agreements: DesignerWare, LLC, Timothy Kelly and Ronald P. Koller, Aspen Way Enterprises..., LLC; Timothy Kelly and Ronald P. Koller; Aspen Way Enterprises, Inc.; Watershed Development Corp...Ware, LLC''; ``Timothy Kelly and Ronald P. Koller''; ``Aspen Way Enterprises, Inc.'';...

  1. New dimension analyses with error analysis for quaking aspen and black spruce

    Science.gov (United States)

    Woods, K. D.; Botkin, D. B.; Feiveson, A. H.

    1987-01-01

    Dimension analysis for black spruce in wetland stands and trembling aspen are reported, including new approaches in error analysis. Biomass estimates for sacrificed trees have standard errors of 1 to 3%; standard errors for leaf areas are 10 to 20%. Bole biomass estimation accounts for most of the error for biomass, while estimation of branch characteristics and area/weight ratios accounts for the leaf area error. Error analysis provides insight for cost effective design of future analyses. Predictive equations for biomass and leaf area, with empirically derived estimators of prediction error, are given. Systematic prediction errors for small aspen trees and for leaf area of spruce from different site-types suggest a need for different predictive models within species. Predictive equations are compared with published equations; significant differences may be due to species responses to regional or site differences. Proportional contributions of component biomass in aspen change in ways related to tree size and stand development. Spruce maintains comparatively constant proportions with size, but shows changes corresponding to site. This suggests greater morphological plasticity of aspen and significance for spruce of nutrient conditions.

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

    Science.gov (United States)

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

    2013-07-01

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

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

    Science.gov (United States)

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

    2013-07-01

    Quaking aspen (Populus tremuloides Michaux) stands are important for biodiversity in conifer-dominated forest landscapes. Our goal was to quantify the consequences of conifer succession on understory diversity and litter quality, as well as associated changes in aspen stand condition. We studied aspen stands on national park land in the transition zone between the northern Sierra Nevada and southern Cascade mountain ranges. We field-measured ten metrics of aspen stand condition in 29 aspen stands. Along a gradient of increasing current conifer cover, we observed decreases in herbaceous species diversity and richness and an increase in forest floor O horizon depth. We interpreted aerial photos from 1952 and 1998 to determine whether directional changes in conifer cover had occurred in the stands over the past half century, and used regression modeling to associate succession with the observed range of aspen stand condition. From the period 1952 to 1998, we found that conifer encroachment occurred in half the sampled stands, with an average increase in conifer cover of 1% a year. Aspen were persistent in the remaining stands. Stand cover dynamics and percent total canopy cover interacted to influence species richness, diversity, aspen sprouting, and litter quality. In stands with conifer encroachment, both understory species richness and diversity declined. Although aspen sprouting increased, aspen establishment declined and the relative mass of woody to fine soil litter increased. PMID:23093369

  4. Models for the distribution of quaking aspen in geographic and potential evapotranspiration spaces relevant to the Book Cliffs (Utah), 2000-2002

    OpenAIRE

    Sexton, Joseph O.

    2003-01-01

    Quaking aspen is the most widely distributed tree species in North America and an asset to sociological, ecological, and hydrological land values in the western United States. In recognition of these values, land managers seek means to oppose a regional decline of aspen in the Intermountain West—a decline apparently in progress since the close of the Pleistocene and driven by climate change, fire suppression, and increasing ungulate densities. One location of special relevance to this decline...

  5. Translating MAPGEN to ASPEN for MER

    Science.gov (United States)

    Rabideau, Gregg R.; Knight, Russell L.; Lenda, Matthew; Maldague, Pierre F.

    2013-01-01

    This software translates MAPGEN (Europa and APGEN) domains to ASPEN, and the resulting domain can be used to perform planning for the Mars Exploration Rover (MER). In other words, this is a conversion of two distinct planning languages (both declarative and procedural) to a third (declarative) planning language in order to solve the problem of faithful translation from mixed-domain representations into the ASPEN Modeling Language. The MAPGEN planning system is an example of a hybrid procedural/declarative system where the advantages of each are leveraged to produce an effective planner/scheduler for MER tactical planning. The adaptation of the planning system (ASPEN) was investigated, and, with some translation, much of the procedural knowledge encoding is amenable to declarative knowledge encoding. The approach was to compose translators from the core languages used for adapting MAGPEN, which consists of Europa and APGEN. Europa is a constraint- based planner/scheduler where domains are encoded using a declarative model. APGEN is also constraint-based, in that it tracks constraints on resources and states and other variables. Domains are encoded in both constraints and code snippets that execute according to a forward sweep through the plan. Europa and APGEN communicate to each other using proxy activities in APGEN that represent constraints and/or tokens in Europa. The composition of a translator from Europa to ASPEN was fairly straightforward, as ASPEN is also a declarative planning system, and the specific uses of Europa for the MER domain matched ASPEN s native encoding fairly closely. On the other hand, translating from APGEN to ASPEN was considerably more involved. On the surface, the types of activities and resources one encodes in APGEN appear to match oneto- one to the activities, state variables, and resources in ASPEN. But, when looking into the definitions of how resources are profiled and activities are expanded, one sees code snippets that access

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

    Science.gov (United States)

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

    2014-05-01

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

  7. 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

  8. Abaxial Greening Phenotype in Hybrid Aspen.

    Science.gov (United States)

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

    2013-04-24

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

  9. Abaxial Greening Phenotype in Hybrid Aspen

    Directory of Open Access Journals (Sweden)

    Julia S. Nowak

    2013-04-01

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

  10. 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

  11. Aspen Delineation - Sierra State Parks [ds380

    Data.gov (United States)

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

  12. Aspen Delineation - Plumas National Forest [ds374

    Data.gov (United States)

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

  13. Aspen Delineation - Lassen National Forest [ds372

    Data.gov (United States)

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

  14. Aspen Delineation - Sequoia National Forest [ds378

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2008-01-01

    As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less man-power rises.Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. 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, 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 ASE project's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

  16. 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.

  17. The incorporation of an organic soil layer in the Noah-MP land surface model and its evaluation over a boreal aspen forest

    Science.gov (United States)

    Chen, Liang; Li, Yanping; Chen, Fei; Barr, Alan; Barlage, Michael; Wan, Bingcheng

    2016-07-01

    A thick top layer of organic matter is a dominant feature in boreal forests and can impact land-atmosphere interactions. In this study, the multi-parameterization version of the Noah land surface model (Noah-MP) was used to investigate the impact of incorporating a forest-floor organic soil layer on the simulated surface energy and water cycle components at the BERMS Old Aspen site (OAS) field station in central Saskatchewan, Canada. Compared to a simulation without an organic soil parameterization (CTL), the Noah-MP simulation with an organic soil (OGN) improved Noah-MP-simulated soil temperature profiles and soil moisture at 40-100 cm, especially the phase and amplitude (Seasonal cycle) of soil temperature below 10 cm. OGN also enhanced the simulation of sensible and latent heat fluxes in spring, especially in wet years, which is mostly related to the timing of spring soil thaw and warming. Simulated top-layer soil moisture is better in OGN than that in CTL. The effects of including an organic soil layer on soil temperature are not uniform throughout the soil depth and are more prominent in summer. For drought years, the OGN simulation substantially modified the partitioning of water between direct soil evaporation and vegetation transpiration. For wet years, the OGN-simulated latent heat fluxes are similar to CTL except for the spring season when OGN produced less evaporation, which was closer to observations. Including organic soil produced more subsurface runoff and resulted in much higher runoff throughout the freezing periods in wet years.

  18. Simulation of IGFC power generation system by Aspen Plus

    DEFF Research Database (Denmark)

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

    2010-01-01

    and therefore, very high efficiencies can be achieved. The outputs from SOFC can be utilized by HRSG which drives steam turbine for electricity production. The SOFC stack model developed using the process flow sheet simulator Aspen Plus which is of equilibrium type. The results indicate there must be tread off...... efficiency and power with respect to a variety of SOFC inputs. HRSG which is located after the SOFC is also included in current simulation study with various operating parameters. This paper also describes for the IGFC Power Plants, the optimization of the Heat Recovery Steam Generator (HRSG......) is of particular interest in order to improve the efficiency of the heat recovery from SOFC exhaust gas and to maximize the power production in the steam cycle in IGFC system....

  19. Aspen Characteristics - Klamath National Forest [ds369

    Data.gov (United States)

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

  20. Aspen Characteristics - Sierra State Parks [ds379

    Data.gov (United States)

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

  1. Aspen Characteristics - Plumas National Forest [ds373

    Data.gov (United States)

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

  2. Aspen Characteristics - Sequoia National Forest [ds377

    Data.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-06-01

    from spruce yield models. The understorey spruce stand produced 106 m{sup 3} of stemwood ha{sup -1} during 44 years, and the overstorey aspens 430 m{sup 3} ha{sup -1}. A pure Norway spruce stand was estimated to produce 490-570 m{sup 3} ha{sup -1} 105 refs, 7 figs, 4 tabs

  4. Aspen Delineation - El Dorado National Forest [ds364

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  6. 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.

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

    Science.gov (United States)

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

    2009-11-01

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

  8. Aspen Characteristics - Lassen National Forest [ds371

    Data.gov (United States)

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

  9. Thermodynamic Phase And Chemical Equilibrium At 0-110 C For The H+-K+-Na+-Cl--H2O System Up To 16 Molal And The HNO3-H2O System Up To 20 Molal Using An Association-Based Pitzer Model Compatible With ASPEN Plus

    Energy Technology Data Exchange (ETDEWEB)

    Nichols,T.T.; Taylor,D.D.

    2003-09-26

    A status is presented of the parameterization during FY2003 of an association-based Pitzer model to simulate chemical and phase equilibria of acid-chloride-nitrate-mercury aqueous electrolyte systems at 0-100 C within the industry-standard process simulator, ASPEN Plus. Compatibility with ASPEN Plus requires that the Pitzer model used be limited to the third virial coefficient and have the values of b and a1 as originally proposed by Pitzer. Two aqueous models for 0-110 C at atmospheric pressure were parameterized in FY03. The model for the aqueous H+-K+-Na+-Cl- system is applicable for 0-16 molal, and the HNO3-H2O for 0-20 molal. An association-based Pitzer activity coefficient model is combined with Henry's law to predict activity/osmotic coefficient and VLE. The chloride model also predicts KCl and NaCl solubility, while the nitric acid model has the unique capability of predicting extent of dissociation with an average absolute deviation of 1.43%. The association-based approach presented here extends the utility of the molality-based Pitzer model past 6 molal to predict activity/osmotic coefficients up to 16-20 molal. The association-based approach offers the additional benefits of predicting extent of dissociation and of allowing the Pitzer model to be fully utilized in commercial simulators, such as ASPEN Plus, that require accounting for association to implement Henry's law. The Pitzer models presented here provide the chemical process simulation engineer with a superior alternative to the Electrolyte NRTL model that can easily be used in ASPEN Plus.

  10. 基于ASPEN PLUS平台的生物质氧气气化制备合成气的模拟研究%Modeling and Simulation of Oxygen Gasification of Biomass for Syngas Gas Production Based on ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    李斌; 陈汉平; 杨海平; 王贤华; 张世红; 代正华

    2011-01-01

    A model of oxygen gasification of biomass for syngas gas production was built using ASPEN PLUS, and the effects of various factors on gasification characteristics were analyzed. The results showed that, as the oxygen biomass equivalence ratio increases, both the synthesis gas concentration and the yield increase first and then de-crease and they both reach the maximum values of 97.63% and 1.61 m3/kg respectively at the equivalence ratio of 0.16, and the ratio of hydrogen to carbon monoxide also reaches the maximum value of 0.98. High temperature and low pressure are beneficial for syngas production, and under pressurized conditions, the temperature, at which a balanced concentration and yield of syngas can be achieved, increases. As the mass ratio of steam to biomass in-creases from 0 to 1.5, the ratio of hydrogen to carbon monoxide rapidly increases from 0.98 to 3.06, while the vol-ume ratio of oxygen to carbon dioxide changes from 1 : 0 to 1 :5, and the ratio of hydrogen to carbon monoxide decreases from 0.98 to 0.50 rapidly.%利用ASPEN PLUS软件建立了生物质氧气气化制备合成气模型,并对各种影响因素进行了深入分析,结果表明,随着O2当量比的增加,合成气的体积分数与产率均先增大后减小,且在当量比为0.16时,合成气的体积分数和产率均达到最大值,分别为97.63%和1.61 m3/kg,此φ(H2)/φ(CO)也有最大值0.98;高温和低压对制备合成气有利,在加压条件下,合成气体积分数和产率达到平衡组成时的温度提高;水蒸气与生物质之比由0增加到1.5时,φ(H2)/φ(CO)的值由0.98快速上升至3.06,而φ(O2)/φ(CO2)的值由1∶0变化到1∶5时,φ(H2)/φ(CO)的值由0.98快速下降至0.50.

  11. Can elevated CO2 and ozone shift the genetic composition of aspen (Populus tremuloides) stands?

    Science.gov (United States)

    Moran, Emily V; Kubiske, Mark E

    2013-04-01

    The world's forests are currently exposed to increasing concentrations of carbon dioxide (CO2) and ozone (O3). Both pollutants can potentially exert a selective effect on plant populations. This, in turn, may lead to changes in ecosystem properties, such as carbon sequestration. Here, we report how elevated CO2 and O3 affect the genetic composition of a woody plant population via altered survival. Using data from the Aspen free-air CO2 enrichment (FACE) experiment (in which aspen clones were grown in factorial combinations of CO2 and O3), we develop a hierarchical Bayesian model of survival. We also examine how survival differences between clones could affect pollutant responses in the next generation. Our model predicts that the relative abundance of the tested clones, given equal initial abundance, would shift under either elevated CO2 or O3 as a result of changing survival rates. Survival was strongly affected by between-clone differences in growth responses. Selection could noticeably decrease O3 sensitivity in the next generation, depending on the heritability of growth responses and the distribution of seed production. The response to selection by CO2, however, is likely to be small. Our results suggest that the changing atmospheric composition could shift the genotypic composition and average pollutant responses of tree populations over moderate timescales.

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

    Data.gov (United States)

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

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

    OpenAIRE

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

    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 discussion of aspen conservation and management techniques such as fencing, conifer removal, and artificial propagation. Local data on bird use of as...

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

    Science.gov (United States)

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

    2007-03-01

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

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

    Science.gov (United States)

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

    2011-03-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-08-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  20. 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.

  1. ASPEN PLUS在氯碱工程设计中的应用——氯氢处理流程模拟开发%Application of ASPEN PLUS in chlorine- alkali engineering design —— Development of imitiative process of chlorine and hydrogen treatment

    Institute of Scientific and Technical Information of China (English)

    杨萍; 邓敏

    2001-01-01

    The binary interaction parameters are derived from gas- liquid equilibrium regression by using the ASPEN PLUS 10. O. Main point in this paper is the introduction of the calculation of mass balance and heat balance in chlorine and hydrogen treatment process in ion - exchange membrane caustic soda production process with the above imitiative flow path software. The calcalation results are compared with actual data from plants,and agreeable results are obtained.%ASPEN PLUS 10.0版中有较为全面的气液平衡回归出来的二元交互作用参数,文中主要介绍了用该流程模拟软件对离子膜烧碱氯氢处理工序进行物料平衡和热量平衡的计算,并与工厂实际数据进行比较,获得满意的结果。

  2. Design, fabrication, operation and Aspen simulation of oil shale pyrolysis and biomass gasification process using a moving bed downdraft reactor

    Science.gov (United States)

    Golpour, Hassan

    Energy is the major facilitator of the modern life. Every developed and developing economy requires access to advanced sources of energy to support its growth and prosperity. Declining worldwide crude oil reserves and increasing energy needs has focused attention on developing existing unconventional fossil fuels like oil shale and renewable resources such as biomass. Sustainable, renewable and reliable resources of domestically produced biomass comparing to wind and solar energy is a sensible motivation to establish a small-scale power plant using biomass as feed to supply electricity demand and heat for rural development. The work in Paper I focuses on the possibility of water pollution from spent oil shale which should be studied before any significant commercial production is attempted. In Paper II, the proposed Aspen models for oil shale pyrolysis is to identify the key process parameters for the reactor and optimize the rate of production of syncrude from oil shale. The work in Paper III focuses on (1) Design and operation of a vertical downdraft reactor, (2) Establishing an optimum operating methodology and parameters to maximize syngas production through process testing. Finally in Paper IV, a proposed Aspen model for biomass gasification simulates a real biomass gasification system discussed in Paper III.

  3. 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

  4. Development of a threshold model to predict germination of Populus tomentosa seeds after harvest and storage under ambient condition.

    Directory of Open Access Journals (Sweden)

    Wei-Qing Wang

    Full Text Available Effects of temperature, storage time and their combination on germination of aspen (Populus tomentosa seeds were investigated. Aspen seeds were germinated at 5 to 30°C at 5°C intervals after storage for a period of time under 28°C and 75% relative humidity. The effect of temperature on aspen seed germination could not be effectively described by the thermal time (TT model, which underestimated the germination rate at 5°C and poorly predicted the time courses of germination at 10, 20, 25 and 30°C. A modified TT model (MTT which assumed a two-phased linear relationship between germination rate and temperature was more accurate in predicting the germination rate and percentage and had a higher likelihood of being correct than the TT model. The maximum lifetime threshold (MLT model accurately described the effect of storage time on seed germination across all the germination temperatures. An aging thermal time (ATT model combining both the TT and MLT models was developed to describe the effect of both temperature and storage time on seed germination. When the ATT model was applied to germination data across all the temperatures and storage times, it produced a relatively poor fit. Adjusting the ATT model to separately fit germination data at low and high temperatures in the suboptimal range increased the models accuracy for predicting seed germination. Both the MLT and ATT models indicate that germination of aspen seeds have distinct physiological responses to temperature within a suboptimal range.

  5. Wood Quality and Growth Characterization across Intra- and Inter-Specific Hybrid Aspen Clones

    Directory of Open Access Journals (Sweden)

    Shawn D. Mansfield

    2013-09-01

    Full Text Available Trembling aspen (Populus tremuloides Michx. is one of the most abundant poplar species in North America; it is native, displays substantial breadth in distribution inhabiting several geographical and climatic ecoregions, is notable for its rapid growth, and is ecologically and economically important. As the demand for raw material continues to increase rapidly, there is a pressing need to improve both tree quality and growth rates via breeding efforts. Hybridization is considered one of the most promising options to simultaneously accelerate these tree characteristics, as it takes advantage of heterosis. Two aspen species showing particular promise for hybridization with trembling aspen are European aspen (P. tremula and Chinese aspen (P. davidiana because their native climates are similar to that of P. tremuloides and are also very easy to hybridize. In 2003, aspen clones were planted in Athabasca, Alberta from the following species crosses: open pollinated (OP P. tremuloides (NN, OP P. davidiana (CC, P. tremula × P. tremula (EE, P. tremula × P. tremuloides (EN, and P. tremuloides × P. davidiana (CN. In November 2010, growth measurements and core samples were taken from seven-year field grown clones. Comparisons of the mean growth and cell wall traits were made between crosses using generalized linear model least squares means tests for stem volume, fiber length, fiber width, coarseness, wood density, microfibril angle, total cell wall carbohydrate and lignin content, and lignin composition. The results clearly indicated that the inter-specific crosses offer a means to breed for more desirable wood characteristics than the intra-specific Populus spp. crosses.

  6. 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.

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

    Science.gov (United States)

    Hamberg, Leena; Hantula, Jarkko

    2016-04-15

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

  8. Aspen Winter Conferences on High Energy

    Energy Technology Data Exchange (ETDEWEB)

    multiple speakers, presenters listed on link below

    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 caf� 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 caf� to discuss dark matter. This report provides the attendee lists, programs, and announcement posters for each event.

  9. Taxonomy Icon Data: quaking aspen [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available quaking aspen Populus tremuloides Populus_tremuloides_L.png Populus_tremuloides_NL.png Populus_trem...uloides_S.png Populus_tremuloides_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+trem...uloides&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+tremuloides&t=NL http://biosc...iencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+tremuloides&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+tremuloides&t=NS ...

  10. 77 FR 60373 - Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and Piute...

    Science.gov (United States)

    2012-10-03

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

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

    Data.gov (United States)

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

  12. Aspen Characteristics - El Dorado National Forest [ds363

    Data.gov (United States)

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

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

    OpenAIRE

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

    2015-01-01

    Background The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes: volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collecte...

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

    Institute of Scientific and Technical Information of China (English)

    陈智强; 陈曦; 邵之江; 张正江

    2007-01-01

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

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

    Science.gov (United States)

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

    2011-12-01

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

  16. 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.

  17. Aspen Competition Drives Innovative Ideas for Community Colleges

    Science.gov (United States)

    Gonzalez, Jennifer

    2012-01-01

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

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

    Science.gov (United States)

    Wyner, Joshua

    2012-01-01

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

  19. Polyploidy in aspen alters plant physiology and drought sensitivity

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2010-06-01

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

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

    Institute of Scientific and Technical Information of China (English)

    陈坚

    2011-01-01

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

  2. 2013 Aspen Winter Conference on particle physics: Higgs Quo Vadis

    CERN Document Server

    2013-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  4. Co-production of science for regional integrated assessment and management of climate change impacts: The case study of Aspen, CO

    Science.gov (United States)

    Arnott, J. C.; Katzenberger, J.

    2015-12-01

    The impacts of global climate change to regional scales are complex and cut across sectorial and jurisdictional boundaries, and therefore, a unique enterprise of collaboration between scientists, resource managers, and other stakeholders for development of adequate response strategies is required. Such collaboration has been exhibited between stakeholders, researchers, and a boundary organization—the Aspen Global Change Institute—since 2005 in assessing impacts and crafting policies in response with regard to climate change impacts in the mountain watershed surrounding Aspen, CO. A series of structured stakeholder interviews and town hall sessions, impact assessment reports, and intensive collaboration between various information providers and user groups has set the stage for development of both mitigation of and adaptation to climate change impacts. The most recent example of this has included the use of global scale climate model output to inform the development of resiliency strategies in response to extreme precipitation projections. The use of this kind of resource has been considered in a variety of decision-making contexts and has included the development of region- and decision-relevant qualitative scenarios that make use of quantitative model-based information. Results from this line of work that include feedback from actual users', a boundary organization, and researchers' perspectives will be reported along with examples of policy and implementation results.

  5. Aspen Increase Soil Moisture, Nutrients, Organic Matter and Respiration in Rocky Mountain Forest Communities

    OpenAIRE

    Buck, Joshua R.; Samuel B. St. Clair

    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 c...

  6. 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

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

    Science.gov (United States)

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

    2013-10-01

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

  8. 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

  9. The Rise of Netpolitik: How the Internet Is Changing International Politics and Diplomacy. A Report of the Annual Aspen Institute Roundtable on Information Technology (11th, Aspen, Colorado, August 1-4, 2002).

    Science.gov (United States)

    Bollier, David

    This document is an interpretive synthesis of the discussion at a conference sponsored by the Aspen Institute that sought to develop new ways to understand how the Internet is changing the powers of the nation-state, the conduct of international relations, and the definitions of nation security. This report examines how the Internet and other…

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

    Directory of Open Access Journals (Sweden)

    Headlee WL

    2015-10-01

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

  11. 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.

  12. Approach and development strategy for an agent-based model of economic confidence.

    Energy Technology Data Exchange (ETDEWEB)

    Sprigg, James A.; Pryor, Richard J.; Jorgensen, Craig Reed

    2004-08-01

    We are extending the existing features of Aspen, a powerful economic modeling tool, and introducing new features to simulate the role of confidence in economic activity. The new model is built from a collection of autonomous agents that represent households, firms, and other relevant entities like financial exchanges and governmental authorities. We simultaneously model several interrelated markets, including those for labor, products, stocks, and bonds. We also model economic tradeoffs, such as decisions of households and firms regarding spending, savings, and investment. In this paper, we review some of the basic principles and model components and describe our approach and development strategy for emulating consumer, investor, and business confidence. The model of confidence is explored within the context of economic disruptions, such as those resulting from disasters or terrorist events.

  13. 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

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

    International Nuclear Information System (INIS)

    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

  15. Developing mathematical modelling competence

    DEFF Research Database (Denmark)

    Blomhøj, Morten; Jensen, Tomas Højgaard

    2003-01-01

    In this paper we introduce the concept of mathematical modelling competence, by which we mean being able to carry through a whole mathematical modelling process in a certain context. Analysing the structure of this process, six sub-competences are identified. Mathematical modelling competence...... cannot be reduced to these six sub-competences, but they are necessary elements in the development of mathematical modelling competence. Experience from the development of a modelling course is used to illustrate how the different nature of the sub-competences can be used as a tool for finding...... the balance between different kinds of activities in a particular educational setting. Obstacles of social, cognitive and affective nature for the students' development of mathematical modelling competence are reported and discussed in relation to the sub-competences....

  16. Aspen Simulation of Diesel-Biodiesel Blends Combustion

    Directory of Open Access Journals (Sweden)

    Pérez-Sánchez Armando

    2015-01-01

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

  17. Somatic Embryogenesis from Cell Suspension Cultures of Aspen Clone

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

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

  18. 78 FR 46312 - Spruce Beetle Epidemic and Aspen Decline Management Response; Grand Mesa, Uncompahgre and...

    Science.gov (United States)

    2013-07-31

    ... Forest Service Spruce Beetle Epidemic and Aspen Decline Management Response; Grand Mesa, Uncompahgre and...,000 acres of aspen forests have experienced substantial mortality from insects and diseases over the..., juniper and ponderosa pine to Engelmann spruce, subalpine fir, and quaking aspen. Tree ring records...

  19. RISK ANALYSIS DEVELOPED MODEL

    Directory of Open Access Journals (Sweden)

    Georgiana Cristina NUKINA

    2012-07-01

    Full Text Available Through Risk analysis developed model deciding whether control measures suitable for implementation. However, the analysis determines whether the benefits of a data control options cost more than the implementation.

  20. Systems analysis of a closed loop ECLSS using the ASPEN simulation tool. Thermodynamic efficiency analysis of ECLSS components. M.S. Thesis

    Science.gov (United States)

    Chatterjee, Sharmista

    1993-01-01

    Our first goal in this project was to perform a systems analysis of a closed loop Environmental Control Life Support System (ECLSS). This pertains to the development of a model of an existing real system from which to assess the state or performance of the existing system. Systems analysis is applied to conceptual models obtained from a system design effort. For our modelling purposes we used a simulator tool called ASPEN (Advanced System for Process Engineering). Our second goal was to evaluate the thermodynamic efficiency of the different components comprising an ECLSS. Use is made of the second law of thermodynamics to determine the amount of irreversibility of energy loss of each component. This will aid design scientists in selecting the components generating the least entropy, as our penultimate goal is to keep the entropy generation of the whole system at a minimum.

  1. Importance of two consecutive methionines at the N-terminus of a cellulose synthase (PtdCesA8A) for normal wood cellulose synthesis in aspen.

    Science.gov (United States)

    Liu, Yunxia; Xu, Fuyu; Gou, Jiqing; Al-Haddad, Jameel; Telewski, Frank W; Bae, Hyeun-Jong; Joshi, Chandrashekhar P

    2012-11-01

    All known orthologs of a secondary wall-associated cellulose synthase (CesA) gene from Arabidopsis, AtCesA8, encode CesA proteins with two consecutive methionines at their N-termini (MM or 2M). Here, we report that these 2Ms in an aspen ortholog of AtCesA8, PtdCesA8A, are important for maintaining normal wood cellulose biosynthesis in aspen trees. Overexpression of an altered PtdCesA8A cDNA encoding a PtdCesA8A protein missing one methionine at the N-terminus (1M) in aspen resulted in substantial decrease in cellulose content and caused negative effects on wood strength, suggesting that both methionines are essential for proper CesA expression and function in developing xylem tissues. Transcripts from a pair of paralogous native PtdCesA8 genes, as well as introduced PtdCesA8A:1M transgenes were significantly reduced in developing xylem tissues of transgenic aspen plants, suggestive of a co-suppression event. Overexpression of a native PtdCesA8A cDNA encoding a CesA protein with 2Ms at the N-terminus did not cause any such phenotypic changes. These results suggest the importance of 2Ms present at the N-terminus of PtdCesA8A protein during cellulose synthesis in aspen.

  2. Reference Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Jepsen, Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2011-11-02

    Presentation from the 2011 Water Peer Review in which principal investigator discusses project progress to develop a representative set of Reference Models (RM) for the MHK industry to develop baseline cost of energy (COE) and evaluate key cost component/system reduction pathways.

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

    Institute of Scientific and Technical Information of China (English)

    薛科创; 许航线

    2014-01-01

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

  4. 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

    ... Aspen Wind Energy Project, Wyoming, and Notice of Segregation of Public Lands AGENCY: Bureau of Land... prepare an Environmental Impact Statement (EIS) for the Quaking Aspen Wind Energy Project (Quaking Aspen... comments and identify potential issues related to the Quaking Aspen EIS; and (2) Segregating 3,698.35...

  5. Simulation of integrated pollutant removal (IPR) water-treatment system using ASPEN Plus

    Energy Technology Data Exchange (ETDEWEB)

    Harendra, Sivaram; Oryshcyhn, Danylo [U.S. DOE/NETL; Ochs, Thomas [U.S. DOE/NETL; Gerdemann, Stephen; Clark, John

    2013-01-01

    Capturing CO2 from fossil fuel combustion provides an opportunity for tapping a significant water source which can be used as service water for a capture-ready power plant and its peripherals. Researchers at the National Energy Technology Laboratory (NETL) have patented a process—Integrated Pollutant Removal (IPR®)—that uses off-the-shelf technology to produce a sequestration ready CO2 stream from an oxy-combustion power plant. Water condensed from oxy-combustion flue gas via the IPR system has been analyzed for composition and an approach for its treatment—for in-process reuse and for release—has been outlined. A computer simulation model in ASPEN Plus has been developed to simulate water treatment of flue gas derived wastewater from IPR systems. At the field installation, water condensed in the IPR process contains fly ash particles, sodium (largely from spray-tower buffering) and sulfur species as well as heavy metals, cations, and anions. An IPR wastewater treatment system was modeled using unit operations such as equalization, coagulation and flocculation, reverse osmosis, lime softening, crystallization, and pH correction. According to the model results, 70% (by mass) of the inlet stream can be treated as pure water, the other 20% yields as saleable products such as gypsum (CaSO4) and salt (NaCl) and the remaining portion is the waste. More than 99% of fly ash particles are removed in the coagulation and flocculation unit and these solids can be used as filler materials in various applications with further treatment. Results discussed relate to a slipstream IPR installation and are verified experimentally in the coagulation/flocculation step.

  6. RESTORATION OF QUAKING ASPEN WOODLANDS INVADED BY WESTERN JUNIPER

    Science.gov (United States)

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

  7. 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…

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

    Science.gov (United States)

    Aspen Institute, 2013

    2013-01-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

  10. Detection of Aspens Using High Resolution Aerial Laser Scanning Data and Digital Aerial Images

    Directory of Open Access Journals (Sweden)

    Kalle Eerikäinen

    2008-08-01

    Full Text Available The aim was to use high resolution Aerial Laser Scanning (ALS data and aerial images to detect European aspen (Populus tremula L. from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM was interpolated from the ALS data with a pulse density of 3.86/m2, low-pass filtered using Height-Based Filtering (HBF and binarized to create the mask needed to separate the ground pixels from the canopy pixels within individual areas. Watershed segmentation was applied to the low-pass filtered CHM in order to create preliminary canopy segments, from which the non-canopy elements were extracted to obtain the final canopy segmentation, i.e. the ground mask was analysed against the canopy mask. A manual classification of aerial images was employed to separate the canopy segments of deciduous trees from those of coniferous trees. Finally, linear discriminant analysis was applied to the correctly classified canopy segments of deciduous trees to classify them into segments belonging to aspen and those belonging to other deciduous trees. The independent variables used in the classification were obtained from the first pulse ALS point data. The accuracy of discrimination between aspen and other deciduous trees was 78.6%. The independent variables in the classification function were the proportion of vegetation hits, the standard deviation of in pulse heights, accumulated intensity at the 90th percentile and the proportion of laser points reflected at the 60th height percentile. The accuracy of classification corresponded to the validation results of earlier ALS-based studies on the classification of individual deciduous trees to tree species.

  11. Product Development Process Modeling

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The use of Concurrent Engineering and other modern methods of product development and maintenance require that a large number of time-overlapped "processes" be performed by many people. However, successfully describing and optimizing these processes are becoming even more difficult to achieve. The perspective of industrial process theory (the definition of process) and the perspective of process implementation (process transition, accumulation, and inter-operations between processes) are used to survey the method used to build one base model (multi-view) process model.

  12. aspenONE先进控制和优化集成解决方案

    Institute of Scientific and Technical Information of China (English)

    竺建敏

    2006-01-01

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

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

    Science.gov (United States)

    Levi, Titus

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-15

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

  15. 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

  16. 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.

  17. Process simulation and maximization of energy output in chemical-looping combustion using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Xiao Zhang, Subhodeep Banerjee, Ling Zhou, Ramesh Agarwal

    2015-01-01

    Full Text Available Chemical-looping combustion (CLC is currently considered as a leading technology for reducing the economic cost of CO2 capture. In this paper, several process simulations of chemical-looping combustion are conducted using the ASPEN Plus software. The entire CLC process from the beginning of coal gasification to the reduction and oxidation of the oxygen carrier is modeled and validated against experimental data. The energy balance of each major component of the CLC process, e.g., the fuel and air reactors and air/flue gas heat exchangers is examined. Different air flow rates and oxygen carrier feeding rates are used in the simulations to obtain the optimum ratio of coal, air, and oxygen carrier that produces the maximum power. Two scaled-up simulations are also conducted to investigate the influence of increase in coal feeding on power generation. It is demonstrated that the optimum ratio of coal, air supply, and oxygen carrier for maximum power generation remains valid for scaled-up cases with substantially larger coal feeding rates; the maximum power generation scales up linearly by using the process simulation models in ASPEN Plus. The energy output from four different types of coals is compared, and the optimum ratio of coal, air supply and oxygen carrier for maximum power generation for each type of coal is determined.

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

    Institute of Scientific and Technical Information of China (English)

    李盛姬; 田端正; 吴江平; 张建君

    2011-01-01

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

  19. IMPACT fragmentation model developments

    Science.gov (United States)

    Sorge, Marlon E.; Mains, Deanna L.

    2016-09-01

    The IMPACT fragmentation model has been used by The Aerospace Corporation for more than 25 years to analyze orbital altitude explosions and hypervelocity collisions. The model is semi-empirical, combining mass, energy and momentum conservation laws with empirically derived relationships for fragment characteristics such as number, mass, area-to-mass ratio, and spreading velocity as well as event energy distribution. Model results are used for several types of analysis including assessment of short-term risks to satellites from orbital altitude fragmentations, prediction of the long-term evolution of the orbital debris environment and forensic assessments of breakup events. A new version of IMPACT, version 6, has been completed and incorporates a number of advancements enabled by a multi-year long effort to characterize more than 11,000 debris fragments from more than three dozen historical on-orbit breakup events. These events involved a wide range of causes, energies, and fragmenting objects. Special focus was placed on the explosion model, as the majority of events examined were explosions. Revisions were made to the mass distribution used for explosion events, increasing the number of smaller fragments generated. The algorithm for modeling upper stage large fragment generation was updated. A momentum conserving asymmetric spreading velocity distribution algorithm was implemented to better represent sub-catastrophic events. An approach was developed for modeling sub-catastrophic explosions, those where the majority of the parent object remains intact, based on estimated event energy. Finally, significant modifications were made to the area-to-mass ratio distribution to incorporate the tendencies of different materials to fragment into different shapes. This ability enabled better matches between the observed area-to-mass ratios and those generated by the model. It also opened up additional possibilities for post-event analysis of breakups. The paper will discuss

  20. 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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2008-08-01

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

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

    Science.gov (United States)

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

    2007-07-01

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

  4. Aquatic Ecosystem Response to Timber Harvesting for the Purpose of Restoring Aspen

    OpenAIRE

    Bobette E Jones; Monika Krupa; Kenneth W Tate

    2013-01-01

    The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003-2010) involved two projects located ...

  5. Genetic Variation in Functional Traits Influences Arthropod Community Composition in Aspen (Populus tremula L.)

    OpenAIRE

    Robinson, Kathryn M; Pär K Ingvarsson; 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 ...

  6. Aspen InfoPlus.21实时数据库管理系统的应用

    Institute of Scientific and Technical Information of China (English)

    肖建荣; 万慧芸

    2013-01-01

    To meet the requirement of chemical plant information management, Aspen Infoplus.21 real-time database manage-ment system is constructed based on the current DCS, LIMS and company office LAN. With this network, DCS plant operation re-al-time data information is acquired, monitored and used directly via OPC interface, DCS batch information is acquired, monitored and used directly via Aspen Production Record Manager and Microsoft SQL Server, LIMS data is acquired, monitored and used di-rectly via ODBC interface, and the open framework is developed. With these excellent applications, we have achieved our high work efficiency, and have eventually improved our plant operation effectiveness.%  针对化工厂信息管理的需要,在现有DCS、LIMS和公司局域网(LAN)基础上,搭建Aspen Infoplus.21实时数据库管理系统,通过OPC接口实时读取、监控、查阅和应用DCS系统数据,通过Aspen Production Record Manag-er及Microsoft SQL Server直接抽取DCS工厂批量工艺批次信息,通过ODBC接口及时读取实验室LIMS产品化验数据,并支持开放框架运用。通过实际应用,提高工作效率,最终提高整个工厂生产运作的有效性。

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

    Science.gov (United States)

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

    2015-01-01

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

  8. Hydraulic conductivity and aquaporin transcription in roots of trembling aspen (Populus tremuloides) seedlings colonized by Laccaria bicolor.

    Science.gov (United States)

    Xu, Hao; Cooke, Janice E K; Kemppainen, Minna; Pardo, Alejandro G; Zwiazek, Janusz J

    2016-07-01

    Ectomycorrhizal fungi have been reported to increase root hydraulic conductivity (L pr) by altering apoplastic and plasma membrane intrinsic protein (PIP)-mediated cell-to-cell water transport pathways in associated roots, or to have little effect on root water transport, depending on the interacting species and imposed stresses. In this study, we investigated the water transport properties and PIP transcription in roots of aspen (Populus tremuloides) seedlings colonized by the wild-type strain of Laccaria bicolor and by strains overexpressing a major fungal water-transporting aquaporin JQ585595. Inoculation of aspen seedlings with L. bicolor resulted in about 30 % colonization rate of root tips, which developed dense mantle and the Hartig net that was restricted in the modified root epidermis. Transcript abundance of the aspen aquaporins PIP1;2, PIP2;1, and PIP2;2 decreased in colonized root tips. Root colonization by JQ585595-overexpressing strains had no significant impact on seedling shoot water potentials, gas exchange, or dry mass; however, it led to further decrease in transcript abundance of PIP1;2 and PIP2;3 and the significantly lower L pr than in non-inoculated roots. These results, taken together with our previous study that showed enhanced root water hydraulics of L. bicolor-colonized white spruce (Picea glauca), suggest that the impact of L. bicolor on root hydraulics varies by the ectomycorrhiza-associated tree species.

  9. Hydraulic conductivity and aquaporin transcription in roots of trembling aspen (Populus tremuloides) seedlings colonized by Laccaria bicolor.

    Science.gov (United States)

    Xu, Hao; Cooke, Janice E K; Kemppainen, Minna; Pardo, Alejandro G; Zwiazek, Janusz J

    2016-07-01

    Ectomycorrhizal fungi have been reported to increase root hydraulic conductivity (L pr) by altering apoplastic and plasma membrane intrinsic protein (PIP)-mediated cell-to-cell water transport pathways in associated roots, or to have little effect on root water transport, depending on the interacting species and imposed stresses. In this study, we investigated the water transport properties and PIP transcription in roots of aspen (Populus tremuloides) seedlings colonized by the wild-type strain of Laccaria bicolor and by strains overexpressing a major fungal water-transporting aquaporin JQ585595. Inoculation of aspen seedlings with L. bicolor resulted in about 30 % colonization rate of root tips, which developed dense mantle and the Hartig net that was restricted in the modified root epidermis. Transcript abundance of the aspen aquaporins PIP1;2, PIP2;1, and PIP2;2 decreased in colonized root tips. Root colonization by JQ585595-overexpressing strains had no significant impact on seedling shoot water potentials, gas exchange, or dry mass; however, it led to further decrease in transcript abundance of PIP1;2 and PIP2;3 and the significantly lower L pr than in non-inoculated roots. These results, taken together with our previous study that showed enhanced root water hydraulics of L. bicolor-colonized white spruce (Picea glauca), suggest that the impact of L. bicolor on root hydraulics varies by the ectomycorrhiza-associated tree species. PMID:26861480

  10. 2012 Aspen Winter Conferences on High Energy and Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-01

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

  11. 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.

  12. Simulation and validation of chemical-looping combustion using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Ling Zhou, Zheming Zhang, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Laboratory-scale experimental studies have demonstrated that Chemical-Looping Combustion (CLC is an advanced technology which holds great potential for high-efficiency low-cost carbon capture. The generated syngas in CLC is subsequently oxidized to CO2 and H2O by reaction with an oxygen carrier. In this paper, process-level models of CLC are established in ASPEN Plus code for detailed simulations. The entire CLC process, from the beginning of coal gasification to reduction and oxidation of the oxygen carrier is modeled. The heat content of each major component such as fuel and air reactors and air/flue gas heat exchangers is carefully examined. Large amount of energy is produced in the fuel reactor, but energy needs to be supplied to the air reactor. The overall performance and efficiency of the modeled CLC systems are also evaluated.

  13. 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.

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

    Institute of Scientific and Technical Information of China (English)

    陈茂兵; 缪明烽; 卢作基

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    朱丽华; 李波

    2016-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Entman, Robert M.; Katz, Michael L.

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

  18. 75 FR 13805 - Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet...

    Science.gov (United States)

    2010-03-23

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet... Aspen Group Resources Corp. because it has not filed any periodic reports since the period...

  19. 76 FR 77591 - Surety Companies Acceptable on Federal Bonds: Aspen American Insurance Company

    Science.gov (United States)

    2011-12-13

    ... Supplement No. 3 to the Treasury Department Circular 570, 2011 Revision, published July 1, 2011, at 76 FR... Fiscal Service Surety Companies Acceptable on Federal Bonds: Aspen American Insurance Company AGENCY.... 9305 to the following company: Aspen American Insurance Company (NAIC 43460). Business Address:...

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

    Directory of Open Access Journals (Sweden)

    R. Justin DeRose

    2014-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

    张春勇; 郑纯智; 汪斌; 张国华; 文颖频; 张纪霞

    2010-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    薛科创; 闫晓前

    2014-01-01

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

  3. 77 FR 10491 - City of Aspen; Notice of Intent To File License Application, Filing of Pre-Application Document...

    Science.gov (United States)

    2012-02-22

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

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

    Institute of Scientific and Technical Information of China (English)

    孙立娟; 王佳; 齐鹏

    2015-01-01

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

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

    Science.gov (United States)

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

    2013-05-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2010-04-01

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

  8. 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

    increases. But, tree growth response should be studied before any conclusions can be drawn regarding biomass production in the experiments. The similarities in plant response to Ashes+N and NPK suggests that Ashes+N can be used as a P and K resource in the fertilization of young stands of birch and hybrid aspen. If the Ashes+N treatment results in increased N availability due to the pH increase, possibly the N dose could be lowered in order to decrease the risks for N leaching without negative effects on tree N uptake. Tools for the prediction of N mineralization need to be developed. The energy harvest for fertilized birch and hybrid aspen appear to be at least as high as for fertilized Norway spruce. Intensive cultivation including fertilization of young stands appears to be energy efficient: the energy input is a small fraction of the increase in energy harvest. Residue based fertilization appears to be more energy efficient than fertilization with NPK. If production systems other than the ones currently applied are more efficient in terms of sustainable energy production it is important to review the funding of research and development within the field. Which species or species mixtures are most efficient under which soil and climatic condition? Management programs and harvesting techniques need to be developed. More studies on fertilization response and energy harvest in deciduous species with and without the use of residue based fertilizers are needed in order to develop guidelines for the sustainable production of forest bio energy. Empirical studies should be combined with modeling studies in order to improve the understanding of the systems and predictability of management measures. Residue based fertilization appears to be attractive both environmentally and economically, but it is important that such systems are evaluated closely in terms of growth response, nutrient leaching, carbon and metal balances, etc. in comparison with conventional fertilization

  9. Process simulation of oxy-combustion for maximization of energy output using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Subhodeep Banerjee, Xiao Zhang, Suraj K. Puvvada, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Oxy-fuel combustion is a next-generation combustion technology that shows promise to address the need of low-cost carbon capture from fossil fueled power plants. Oxy-fuel combustion requires expensive pre-processing in an air separation unit to separate pure oxygen from air for the combustion process, which reduces the overall efficiency of the process. This paper employs ASPEN Plus process simulation software to model a simple oxy-fuel combustor and investigates the effect of various parameters on the energy output. The composition of the flue gas is carefully examined. The results of this study provide a starting point for optimized oxy-fuel combustion operation for maximum energy output, which will be crucial for future deployment of oxy-fuel combustion technology.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2008-01-01

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

  12. Physiological water model development

    Science.gov (United States)

    Doty, Susan

    1993-01-01

    The water of the human body can be categorized as existing in two main compartments: intracellular water and extracellular water. The intracellular water consists of all the water within the cells and constitutes over half of the total body water. Since red blood cells are surrounded by plasma, and all other cells are surrounded by interstitial fluid, the intracellular compartment has been subdivided to represent these two cell types. The extracellular water, which includes all of the fluid outside of the cells, can be further subdivided into compartments which represent the interstitial fluid, circulating blood plasma, lymph, and transcellular water. The interstitial fluid surrounds cells outside of the vascular system whereas plasma is contained within the blood vessels. Avascular tissues such as dense connective tissue and cartilage contain interstitial water which slowly equilibrates with tracers used to determine extracellular fluid volume. For this reason, additional compartments are sometimes used to represent these avascular tissues. The average size of each compartment, in terms of percent body weight, has been determined for adult males and females. These compartments and the forces which cause flow between them are presented. The kidneys, a main compartment, receive about 25 percent of the cardiac output and filters out a fluid similar to plasma. The composition of this filtered fluid changes as it flows through the kidney tubules since compounds are continually being secreted and reabsorbed. Through this mechanism, the kidneys eliminate wastes while conserving body water, electrolytes, and metabolites. Since sodium accounts for over 90 percent of the cations in the extracellular fluid, and the number of cations is balanced by the number of anions, considering the renal handling sodium and water only should sufficiently describe the relationship between the plasma compartment and kidneys. A kidney function model is presented which has been adapted from a

  13. Econometric models for biohydrogen development.

    Science.gov (United States)

    Lee, Duu-Hwa; Lee, Duu-Jong; Veziroglu, Ayfer

    2011-09-01

    Biohydrogen is considered as an attractive clean energy source due to its high energy content and environmental-friendly conversion. Analyzing various economic scenarios can help decision makers to optimize development strategies for the biohydrogen sector. This study surveys econometric models of biohydrogen development, including input-out models, life-cycle assessment approach, computable general equilibrium models, linear programming models and impact pathway approach. Fundamentals of each model were briefly reviewed to highlight their advantages and disadvantages. The input-output model and the simplified economic input-output life-cycle assessment model proved most suitable for economic analysis of biohydrogen energy development. A sample analysis using input-output model for forecasting biohydrogen development in the United States is given.

  14. Educational Game Development Models

    Directory of Open Access Journals (Sweden)

    Mehmet Emin Korkusuz

    2013-12-01

    Full Text Available Recent research on the subject shows that students spend more time on computer games than other activities such as reading book or watching TV. It is possible that this time-consuming activity can become much more effective by educator-game sector cooperation. Which type of game students prefer mostly; how the educational content can be articulated the games without diminishing the playability and enjoyableness of it; and the impact of the competition in the games on process and students are just several titles examined in the studies. This scope presents the types of computer game, qualities of educational games, and educational games designs which are recommended for developing educational games. It also presents a set of knowledge about the importance of educational games in mathematics and physic education, and some studies on this field. In the scope, some strategies, about educational game development process, are recommended educators and software developers in the sector who intend to develop educational games based on the literature.

  15. Modeling Auxin-regulated Development

    OpenAIRE

    Krupinski, Pawel; Jönsson, Henrik

    2010-01-01

    The phytohormone auxin plays an essential role in many aspects of plant growth and development. Its patterning, intercellular transport, and means of signaling have been extensively studied both in experiments and computational models. Here, we present a review of models of auxin-regulated development in different plant tissues. This includes models of organ initiation in the shoot apical meristem, development of vascular strands in leafs and stems, and auxin-related functioning in roots. The...

  16. Models for Sustainable Regional Development

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    2008-01-01

    The chapter presents a model for integrated cross-cultural knowledge building and entrepreneurship. In addtion, narrative and numeric simulations methods are suggested to promote a further development and implementation of the model in China.......The chapter presents a model for integrated cross-cultural knowledge building and entrepreneurship. In addtion, narrative and numeric simulations methods are suggested to promote a further development and implementation of the model in China....

  17. Analysis of CO2 Separation by Selexol Based on Aspen Plus%基于Aspen Plus对Selexol分离CO2流程的分析

    Institute of Scientific and Technical Information of China (English)

    邱朋华; 李丹丹; 徐宝龙; 呼姚; 杜昌帅; 吴少华

    2014-01-01

    整体煤气化联合循环发电系统可采取燃烧前捕集CO2的方法,处理的合成气量少,能耗低,且能够实现 CO2的近零排放,在 CO2脱除方面具有很大的优势。文中基于Aspen Plus 对 CO2/H2S 联合脱除和分别脱除流程建立了模型,对2流程的能耗、CO2及H2S的脱除效率以及Selexol溶液的再生性能进行了分析。得出:在出口 CO2纯度相同的情况下,CO2/H2S联合脱除流程的能耗仅占CO2/H2S分别脱除的21%左右,CO2脱除效率高于分别脱除流程,2流程Selexol溶液的再生性能相差不大,且H2S脱除效率也可达到95%以上,因此CO2/H2S联合脱除流程更经济。%Integrated gasification combined cycle (IGCC)power generation system can adopt pre-combustion CO2 capture methods, handling with less syngas and have low energy consumption, which can achieve near-zero emissions of CO2, resulting in great advantages in terms of CO2 removal. Based on Aspen Plus, combined removal of CO2/H2S (CRCH) and separate removal of CO2/H2S (SRCH) were modeled . Energy consumption, capture efficiency of CO2 and H2S, as well as the regeneration performance of Selexol were analyzed by the two models. The results indicate that:while keeping the same CO2 purity in outlet stream, the energy consumption of CRCH accounts for only 21% of SRCH; the CO2 capture efficiency is higher than that of SRCH, the regeneration performance of Selexol is almost the same for the two processes, and the capture efficiency of H2S in the two processes can be higher than 95%. All those prove that CRCH is more economic than SRCH.

  18. DEVELOPMENT OF TECHNOLOGIES AND ANALYTICAL CAPABILITIES FOR VISION 21 ENERGY PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Madhava Syamlal, Ph.D.`

    2001-04-20

    The project management plan was finalized during a project kick off meeting held on January 16, 2001 in Lebanon, NH, which was attended by all project participants. The project management plan was submitted to DOE and was revised based on comments from DOE (Task 1.0). A survey of the potential users of the integrated software was conducted. A web-based survey form was developed and was announced in the ProcessCity discussion forum and in AspenTech's e-mail digest Aspen e-Flash. Several Fluent clients were individually contacted. A user requirements document was written (Task 2.2). As a prototype of AspenPlus-Fluent integration, the flowsheet for allyl alcohol production via the isomerization of propylene oxide was developed. A stirred tank reactor in the flowsheet for converting the byproduct acetone into n-propyl propionate was modeled with Fluent, version 5.4. The convergence of the AspenPlus-Fluent integrated model was demonstrated, and a list of data exchanges required between AspenPlus and Fluent was developed (Task 2.6). As the first demonstration case, the RP and L power plant was selected. A planning meeting was held on February 13, 2001 in Cambridge, MA to discuss this demonstration case. It was decided that the steam-side of the power plant would be modeled with AspenPlus and the gas-side, with the ALSTOM Power in-house code INDVU. A flowsheet model of the power plant was developed (Task 3.1). Three positive responses were received for the invitation to join the project Advisory Board. It was decided to expand the membership on the Advisory Board to include other industrial users interested in integrating AspenPlus and Fluent. Additional invitations were sent out (Task 5.0). Integraph's role in the project was restructured based on discussions among the project participants. Fluent hired Dr. Maxwell Osawe to work on the project. Dr. Osawe brings to the project a unique combination of skills (expertise in CFD and object-oriented design and

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

    Science.gov (United States)

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

    2014-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

  1. 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).

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

    Institute of Scientific and Technical Information of China (English)

    林发现; 丁玲; 陈延林; 李繁荣; 师慧灵; 邹隐文

    2011-01-01

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

  3. COMPUTATIONAL MODELS FOR SUSTAINABLE DEVELOPMENT

    OpenAIRE

    Monendra Grover; Rajesh Kumar; Tapan Kumar Mondal; S. Rajkumar

    2011-01-01

    Genetic erosion is a serious problem and computational models have been developed to prevent it. The computational modeling in this field not only includes (terrestrial) reserve design, but also decision modeling for related problems such as habitat restoration, marine reserve design, and nonreserve approaches to conservation management. Models have been formulated for evaluating tradeoffs between socioeconomic, biophysical, and spatial criteria in establishing marine reserves. The percolatio...

  4. ASPEN: A Framework for Automated Planning and Scheduling of Spacecraft Control and Operations

    Science.gov (United States)

    Yan, David; Fukunaga, Alex S.; Rabideau, Gregg; Chien, Steve

    1997-01-01

    In this paper, we describe ASPEN (Automated Planning/Scheduling Environment), a modular, reconfigurable application framework which is capable of supporting a wide variety of planning and scheduling applications.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pacific Northwest National Laboratory & Oak Ridge National Laboratory

    2010-12-01

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

  6. Advanced Mirror & Modelling Technology Development

    Science.gov (United States)

    Effinger, Michael; Stahl, H. Philip; Abplanalp, Laura; Maffett, Steven; Egerman, Robert; Eng, Ron; Arnold, William; Mosier, Gary; Blaurock, Carl

    2014-01-01

    The 2020 Decadal technology survey is starting in 2018. Technology on the shelf at that time will help guide selection to future low risk and low cost missions. The Advanced Mirror Technology Development (AMTD) team has identified development priorities based on science goals and engineering requirements for Ultraviolet Optical near-Infrared (UVOIR) missions in order to contribute to the selection process. One key development identified was lightweight mirror fabrication and testing. A monolithic, stacked, deep core mirror was fused and replicated twice to achieve the desired radius of curvature. It was subsequently successfully polished and tested. A recently awarded second phase to the AMTD project will develop larger mirrors to demonstrate the lateral scaling of the deep core mirror technology. Another key development was rapid modeling for the mirror. One model focused on generating optical and structural model results in minutes instead of months. Many variables could be accounted for regarding the core, face plate and back structure details. A portion of a spacecraft model was also developed. The spacecraft model incorporated direct integration to transform optical path difference to Point Spread Function (PSF) and between PSF to modulation transfer function. The second phase to the project will take the results of the rapid mirror modeler and integrate them into the rapid spacecraft modeler.

  7. Multiplicity Analysis in Reactive Distillation Column Using ASPEN PLUS%反应精馏过程中的多稳态分析

    Institute of Scientific and Technical Information of China (English)

    杨伯伦; 吴江; 赵国胜; 王华军; 路士庆

    2006-01-01

    Reactive distillation processes for synthesis of ethylene glycol (EG) and ethyl tert-butyl ether (ETBE) were modeled with the simulation package ASPEN PLUS. The input multiplicity and output multiplicity were discussed with the method of sensitivity analysis for both cases. In EG production process, steady state multiplicities were studied in terms of effective liquid holdup volume and boil-up ratio. In ETBE synthesis process, the user kinetic subroutine was supplied into ASPEN PLUS firstly, and then the composition, temperature and reaction-rate profiles within the reactive distillation column were presented in detail. A set of stable solution branches based on distinct initial guesses for a range of boil-up ratio were found in EG synthesis. Input multiplicities were observed for a range of reboiler duty at several values of reflux ratio for ETBE synthesis process. These results can be used to avoid excessive energy consumption and achieve optimum design of reactive distillation column.

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

    OpenAIRE

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

    2013-01-01

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

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

    OpenAIRE

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

    2013-01-01

    Aim: Quaking aspen (Populus tremuloides) has the largest natural distribution of any tree native to North America. The primary objectives of this study were to characterize range-wide genetic diversity and genetic structuring in quaking aspen, and to assess the influence of glacial history and rear-edge dynamics. Location: North America. Methods: Using a sample set representing the full longitudinal and latitudinal extent of the species’ distribution, we examined geographical patterns o...

  10. Space Flight Cable Model Development

    Science.gov (United States)

    Spak, Kaitlin

    2013-01-01

    This work concentrates the modeling efforts presented in last year's VSGC conference paper, "Model Development for Cable-Harnessed Beams." The focus is narrowed to modeling of space-flight cables only, as a reliable damped cable model is not yet readily available and is necessary to continue modeling cable-harnessed space structures. New experimental data is presented, eliminating the low-frequency noise that plagued the first year's efforts. The distributed transfer function method is applied to a single section of space flight cable for Euler-Bernoulli and shear beams. The work presented here will be developed into a damped cable model that can be incorporated into an interconnected beam-cable system. The overall goal of this work is to accurately predict natural frequencies and modal damping ratios for cabled space structures.

  11. The Internet and Global Telecommunications: Exploring the Boundaries of International Coordination. A Report of the Annual Aspen Institute Roundtable on International Telecommunications (4th, Shonan Village Center, Japan, September 21-24, 1998).

    Science.gov (United States)

    Kleeman, Michael J.

    The goals of the Fourth Annual Aspen Institute Roundtable on International Telecommunications were: to address procedural and substantive solutions for international coordination of Internet policy issues; to suggest different models for dispute resolution and policy coordination that might be employed in the various contexts of Internet usage;…

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

    Science.gov (United States)

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

    2011-04-01

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

  13. 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.

  14. 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.

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

    Institute of Scientific and Technical Information of China (English)

    卢泽湘; 范立维; 廖益强

    2010-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    滑纬博; 李云凯; 吕燕

    2013-01-01

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

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

    Science.gov (United States)

    Mauriat, Mélanie; Moritz, Thomas

    2009-06-01

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

  18. 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.

  19. Hot-gas cleanup system model development. Volume I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, K.; Bennett, A.; Bekowies, P.J.

    1982-11-01

    This two-volume report summarizes the state of the art in performance modeling of advanced high-temperature, high-pressure (HTHP) gas cleanup devices. Volume I contains the culmination of the research effort carried over the past 12 months and is a summary of research achievements. Volume II is the user's manual for the computer programs developed under the present research project. In this volume, Section 2 presents background information on pressurized, fluidized-bed combustion concepts, a description of the role of the advanced gas cleanup systems, and a list of advanced gas cleanup systems that are currently in development under DOE sponsorship. Section 3 describes the methodology for the software architecture that forms the basis of the well-disciplined and structured computer programs developed under the present project. Section 4 reviews the fundamental theories that are important in analyzing the cleanup performance of HTHP gas filters. Section 5 discusses the effect of alkali agents in HTHP gas cleanup. Section 6 evaluates the advanced HTHP gas cleanup models based on their mathematical integrity, availability of supporting data, and the likelihood of commercialization. As a result of the evaluation procedure detailed in Section 6, five performance models were chosen to be incorporated into the overall system simulation code, ASPEN. These five models (the electrocyclone, ceramic bag filter, moving granular bed filter, electrostatic granular bed filter, and electrostatic precipitator) are described in Section 7. The method of cost projection for these five models is discussed in Section 8. The supporting data and validation of the computer codes are presented in Section 9, and finally the conclusions and recommendations for the HTHP gas cleanup system model development are given in Section 10. 72 references, 19 figures, 25 tables.

  20. Detailed Modeling of Distillation Technologies for Closed-Loop Water Recovery Systems

    Science.gov (United States)

    Allada, Rama Kumar; Lange, Kevin E.; Anderson, Molly S.

    2011-01-01

    Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA?s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents efforts to develop chemical process simulations for three technologies: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system and the Wiped-Film Rotating Disk (WFRD) using the Aspen Custom Modeler and Aspen Plus process simulation tools. The paper discusses system design, modeling details, and modeling results for each technology and presents some comparisons between the model results and recent test data. Following these initial comparisons, some general conclusions and forward work are discussed.

  1. Dynamic characteristics of Oxy-CFB combustion system based on Aspen%基于Aspen平台的Oxy-CFB燃烧侧动态特性模拟

    Institute of Scientific and Technical Information of China (English)

    周建新; 邵壮; 李崇; 司风琪; 徐治皋

    2014-01-01

    Taking an oxy-fuel circulating fluidized bed (Oxy-CFB )combustor pilot facility as the simulation object,a steady-state model for the Oxy-CFB combustion system was built with the plat-form of Aspen Plus.After modifying the steady-state model for the dynamic process simulation,a new dynamic model for the combustion system was built based on Aspen Dynamics and the results were validated by the test data.The simulation study on the responses of the bed temperature and the components,including carbon dioxide,oxygen,carbon monoxide,and nitrogen monoxide in the flue gas,was carried out.The research results show that the dynamic model based on Aspen pro-vides a new method to investigate the dynamic characteristics of the Oxy-CFB combustion system. The dynamic response characteristics of bed temperature and gas components for the coal feed and primary air step changes can provide valuable information for design and implementation of the con-trol system of the Oxy-CFB combustion system.%以某循环流化床富氧燃烧中试系统为模拟对象,借助Aspen Plus流程模拟软件搭建了Oxy-CFB燃烧系统的稳态模型。在此基础上针对动态过程模拟进行改进,并利用Aspen Dynam-ics平台建立了该燃烧系统的动态模型,利用试验数据对模拟结果进行了验证。基于动态模型对Oxy-CFB床温以及燃烧排放产物中二氧化碳、氧气、一氧化碳、一氧化氮等进行了仿真研究。研究表明,基于Aspen平台的动态过程模拟为Oxy-CFB锅炉燃烧系统的动态特性分析提供了新的研究手段,模拟所得的床温及烟气各组分随给煤量、一次风量阶跃变化的动态响应规律可为今后Oxy-CFB燃烧系统的控制设计提供重要依据。

  2. Developing A Holistic Wellness Model

    Directory of Open Access Journals (Sweden)

    D. A. Els

    2006-11-01

    Full Text Available The objective of the present study was the development of a holistic theoretical wellness model that served as frame of reference for the construction of a valid and reliable inventory that was considered suitable for the assessment of wellness of employees of a South African life insurance organisation. The 5 Factor Wellness Inventory was developed from existing proven wellness inventories. A non-random sample of 673 employees of the organisation concerned participated in a cross-sectional survey by completing the Inventory and a biographical questionnaire. Goodness of fit between the holistic wellness model and a data set derived from the application of the 5 Factor Wellness Inventory was determined empirically. The structural equation modelling statistics produced acceptable goodnessof- fit indices albeit with some scope for improvement. The Root Mean Square Error of Approximation indices supported acceptance of the holistic work-wellness model. The validity of the Inventory was also estimated.

  3. COMPUTATIONAL MODELS FOR SUSTAINABLE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Monendra Grover

    2011-02-01

    Full Text Available Genetic erosion is a serious problem and computational models have been developed to prevent it. The computational modeling in this field not only includes (terrestrial reserve design, but also decision modeling for related problems such as habitat restoration, marine reserve design, and nonreserve approaches to conservation management. Models have been formulated for evaluating tradeoffs between socioeconomic, biophysical, and spatial criteria in establishing marine reserves. The percolation theory and shortest path modeling have also been used. In this article we discuss the computational models that have been developed keeping in mind the sustainable developmentConservationists estimate that alarming rate at which biological species are disappearing will have an indelible impact on humanity. Targets which were set in 2002 to reduce the biodiversity loss by 2010 have not been met. The third global diversity outlook report said that loss of wildlife and habitats could not only exacerbate climate change through rising emissions but could also have a negative impact on food sources and industry.

  4. OSPREY Model Development Status Update

    Energy Technology Data Exchange (ETDEWEB)

    Veronica J Rutledge

    2014-04-01

    During the processing of used nuclear fuel, volatile radionuclides will be discharged to the atmosphere if no recovery processes are in place to limit their release. The volatile radionuclides of concern are 3H, 14C, 85Kr, and 129I. Methods are being developed, via adsorption and absorption unit operations, to capture these radionuclides. It is necessary to model these unit operations to aid in the evaluation of technologies and in the future development of an advanced used nuclear fuel processing plant. A collaboration between Fuel Cycle Research and Development Offgas Sigma Team member INL and a NEUP grant including ORNL, Syracuse University, and Georgia Institute of Technology has been formed to develop off gas models and support off gas research. Georgia Institute of Technology is developing fundamental level model to describe the equilibrium and kinetics of the adsorption process, which are to be integrated with OSPREY. This report discusses the progress made on expanding OSPREY to be multiple component and the integration of macroscale and microscale level models. Also included in this report is a brief OSPREY user guide.

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

    Institute of Scientific and Technical Information of China (English)

    岳芳华; 刘东斌; 申延明

    2014-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    薛科创

    2014-01-01

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

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

    Science.gov (United States)

    McGuire, Georgianna; Nicolau, Siobhan

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

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

    Science.gov (United States)

    Entman, Robert M.

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

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

    Science.gov (United States)

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

    2008-08-01

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

  10. 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

  11. 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.

    2010-01-01

    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

  12. Motorola Secure Software Development Model

    Directory of Open Access Journals (Sweden)

    Francis Mahendran

    2008-08-01

    Full Text Available In today's world, the key to meeting the demand for improved security is to implement repeatable processes that reliably deliver measurably improved security. While many organizations have announced efforts to institutionalize a secure software development process, there is little or no industry acceptance for a common process improvement framework for secure software development. Motorola has taken the initiative to develop such a framework, and plans to share this with the Software Engineering Institute for possible inclusion into its Capability Maturity Model Integration (CMMI®. This paper will go into the details of how Motorola is addressing this issue. The model that is being developed is designed as an extension of the existing CMMI structure. The assumption is that the audience will have a basic understanding of the SEI CMM® / CMMI® process framework. The paper will not describe implementation details of a security process model or improvement framework, but will address WHAT security practices are required for a company with many organizations operating at different maturity levels. It is left to the implementing organization to answer the HOW, WHEN, WHO and WHERE aspects. The paper will discuss how the model is being implemented in the Motorola Software Group.

  13. 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.

  14. 13C Tracking after 13CO2 Supply Revealed Diurnal Patterns of Wood Formation in Aspen.

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2010-04-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  17. 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.

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

    Science.gov (United States)

    Schwartz, Evan I.

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

  19. Developing a Malaysia flood model

    Science.gov (United States)

    Haseldine, Lucy; Baxter, Stephen; Wheeler, Phil; Thomson, Tina

    2014-05-01

    Faced with growing exposures in Malaysia, insurers have a need for models to help them assess their exposure to flood losses. The need for an improved management of flood risks has been further highlighted by the 2011 floods in Thailand and recent events in Malaysia. The increasing demand for loss accumulation tools in Malaysia has lead to the development of the first nationwide probabilistic Malaysia flood model, which we present here. The model is multi-peril, including river flooding for thousands of kilometres of river and rainfall-driven surface water flooding in major cities, which may cause losses equivalent to river flood in some high-density urban areas. The underlying hazard maps are based on a 30m digital surface model (DSM) and 1D/2D hydraulic modelling in JFlow and RFlow. Key mitigation schemes such as the SMART tunnel and drainage capacities are also considered in the model. The probabilistic element of the model is driven by a stochastic event set based on rainfall data, hence enabling per-event and annual figures to be calculated for a specific insurance portfolio and a range of return periods. Losses are estimated via depth-damage vulnerability functions which link the insured damage to water depths for different property types in Malaysia. The model provides a unique insight into Malaysian flood risk profiles and provides insurers with return period estimates of flood damage and loss to property portfolios through loss exceedance curve outputs. It has been successfully validated against historic flood events in Malaysia and is now being successfully used by insurance companies in the Malaysian market to obtain reinsurance cover.

  20. 76 FR 15306 - Aspen Merchant Energy LP; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2011-03-21

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

  1. 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

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

    Science.gov (United States)

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

    2012-09-01

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

  3. Aspen Plus”软件在化工生产中的应用

    Institute of Scientific and Technical Information of China (English)

    徐增花

    2013-01-01

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

  4. ASPEN PLUS在化工教学及科研中的应用

    Institute of Scientific and Technical Information of China (English)

    张毅博; 刘杨

    2015-01-01

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

  5. Aspen Plus在化工专业教学中的应用

    Institute of Scientific and Technical Information of China (English)

    韩慧艳

    2013-01-01

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

  6. 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

  7. 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.

  8. Aspen Plus在泵选型设计中的应用

    Institute of Scientific and Technical Information of China (English)

    黄卫国

    2007-01-01

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

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

    Directory of Open Access Journals (Sweden)

    N. M. Nazarenko

    2010-09-01

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

  10. Development Model for Research Infrastructures

    Science.gov (United States)

    Wächter, Joachim; Hammitzsch, Martin; Kerschke, Dorit; Lauterjung, Jörn

    2015-04-01

    . The maturity of individual scientific domains differs considerably. • Technologically and organisationally many different RI components have to be integrated. Individual systems are often complex and have a long-term history. Existing approaches are on different maturity levels, e.g. in relation to the standardisation of interfaces. • The concrete implementation process consists of independent and often parallel development activities. In many cases no detailed architectural blue-print for the envisioned system exists. • Most of the funding currently available for RI implementation is provided on a project basis. To increase the synergies in infrastructure development the authors propose a specific RI Maturity Model (RIMM) that is specifically qualified for open system-of-system environments. RIMM is based on the concepts of Capability Maturity Models for organisational development, concretely the Levels of Conceptual Interoperability Model (LCIM) specifying the technical, syntactical, semantic, pragmatic, dynamic, and conceptual layers of interoperation [1]. The model is complemented by the identification and integration of growth factors (according to the Nolan Stages Theory [2]). These factors include supply and demand factors. Supply factors comprise available resources, e.g., data, services and IT-management capabilities including organisations and IT-personal. Demand factors are the overall application portfolio for RIs but also the skills and requirements of scientists and communities using the infrastructure. RIMM thus enables a balanced development process of RI and RI components by evaluating the status of the supply and demand factors in relation to specific levels of interoperability. [1] Tolk, A., Diallo, A., Turnitsa, C. (2007): Applying the Levels of Conceptual Interoperability Model in Support of Integratability, Interoperability, and Composability for System-of-Systems Engineering. Systemics, Cybernetics and Informatics, Volume 5 - Number 5. [2

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

    Institute of Scientific and Technical Information of China (English)

    孙献菊

    2006-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    范峻铭; 诸林

    2014-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    姬加良

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    堵祖荫

    2002-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    杨云; 许祥军

    2009-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    戚一文; 方云进

    2007-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    曾开亮

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    杨绪壮; 屈一新

    2001-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    高彤; 赵熠

    2008-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    刘春法; 孙剑; 阮栋

    2005-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    徐宝学

    2008-01-01

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

  2. ASPEN Plus simulation of coal integrated gasification combined blast furnace slag waste heat recovery system

    International Nuclear Information System (INIS)

    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

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

    Institute of Scientific and Technical Information of China (English)

    路华清

    2010-01-01

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

  4. The Application of Aspen Energy Analyzer in Analysis and Synthesis for Chemical Engineering Process%Aspen Energy Analyzer在化工过程分析与合成课程教学中的应用

    Institute of Scientific and Technical Information of China (English)

    薄守石

    2015-01-01

    化工过程分析与合成是化工类实践性非常强的专业基础课。在过程工业中,能量是通过换热网络进行传递的,换热网络设计是此课程教学过程中的重要内容之一。本文应用夹点技术,采用Aspen Energy Analyzer软件对简单的换热网络进行分析、综合和优化,使学生更加容易理解和掌握夹点的基础理论,同时使学生熟悉该软件的使用,为后续化工设计和毕业设计的相关换热网络研究打下基础,也可为日后的科研开发、工程设计和生产管理提供了一种有力的技术手段。%Analysis and Synthesis for Chemical Engineering Process is one of the important courses in chemical engineering subject with strong practice.The energy transfer occurs in heat exchanger network in process industry, and the design of heat exchanger network is the important part for this course teaching.Pinch technology was used to analyze the heat exchanger network, this network with the help of Aspen Energy Analyzer software was optimized.Students were helped to use this software skillfully and prepare for the chemical design.At the same time, the software was a powerful means in scientific developing, process design and production management.

  5. Developing the Framed Standard Model

    CERN Document Server

    Baker, Michael J; Chan, H M; Tsou, S T

    2011-01-01

    The framed standard model (FSM) suggested earlier, which incorporates the Higgs field and 3 fermion generations as part of the framed gauge theory structure, is here developed further to show that it gives both quarks and leptons hierarchical masses and mixing matrices akin to what is experimentally observed. Among its many distinguishing features which lead to the above results are (i) the vacuum is degenerate under a global $su(3)$ symmetry which plays the role of fermion generations, (ii) the fermion mass matrix is "universal", rank-one and rotates (changes its orientation in generation space) with changing scale $\\mu$, (iii) the metric in generation space is scale-dependent too, and in general non-flat, (iv) the theta-angle term in the QCD action of topological origin gets transformed into the CP-violating phase of the CKM matrix for quarks, thus offering at the same time a solution to the strong CP problem.

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

    Directory of Open Access Journals (Sweden)

    Arvo Tullus

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

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

    Science.gov (United States)

    Stratman, James F.; And Others

    1995-01-01

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

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

    Science.gov (United States)

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

    2011-03-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  10. Continuous Hydrothermal Co-liquefaction of Aspen Wood and Glycerol with Water Phase Recirculation

    DEFF Research Database (Denmark)

    Pedersen, Thomas Helmer; Grigoras, Ionela; Hoffmann, Jessica;

    2016-01-01

    reactors, although a continuous and energy-efficient operation is paramount for such process to be feasible. In this work an experimental campaign in a continuous bench scale unit is presented. The campaign is based on glycerol-assisted hydrothermal liquefaction of aspen wood carried out with the presence...

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

    Science.gov (United States)

    Hill, W. Leigh; Anthony, Matthew

    1991-01-01

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

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

    Science.gov (United States)

    Rockstraw, David A.

    2005-01-01

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

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

    Science.gov (United States)

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

    2013-06-21

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

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

    Institute of Scientific and Technical Information of China (English)

    Tord Johansson

    2013-01-01

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

  15. 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.

  16. 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…

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

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

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

    Science.gov (United States)

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

    2011-06-01

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

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

    Science.gov (United States)

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

    2013-11-01

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

  20. Developing Personal Network Business Models

    DEFF Research Database (Denmark)

    Saugstrup, Dan; Henten, Anders

    2006-01-01

    The aim of the paper is to examine the issue of business modeling in relation to personal networks, PNs. The paper builds on research performed on business models in the EU 1ST MAGNET1 project (My personal Adaptive Global NET). The paper presents the Personal Network concept and briefly reports...... on the 'state of the art' in the field of business modeling. Furthermore, the paper suggests three generic business models for PNs: a service oriented model, a self-organized model, and a combination model. Finally, examples of relevant services and applications in relation to three different cases...... are presented and analyzed in light of business modeling of PN....

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

    Science.gov (United States)

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

    2012-12-01

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

  2. Modelling and analysis of offshore energy systems on North Sea oil and gas platforms

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Elmegaard, Brian; Pierobon, Leonardo;

    2012-01-01

    export, and power generation. In this paper, a generic model of a North Sea oil and gas platform is described and the most thermodynamically inefficient processes are identified by performing an exergy analysis. Models and simulations are built and run with the tools Aspen Plus R, DNA and Aspen HYSYS R...

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

    Institute of Scientific and Technical Information of China (English)

    薛科创

    2014-01-01

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

  4. The Validation of the Mixedwood Growth Model (MGM for Use in Forest Management Decision Making

    Directory of Open Access Journals (Sweden)

    Mike Bokalo

    2013-01-01

    Full Text Available We evaluated the Mixedwood Growth Model (MGM at a whole model scale for pure and mixed species stands of aspen and white spruce in the western boreal forest. MGM is an individual tree-based, distance-independent growth model, designed to evaluate growth and yield implications relating to the management of white spruce, black spruce, aspen, lodgepole pine, and mixedwood stands in Alberta, British Columbia, Saskatchewan, and Manitoba. Our validation compared stand-level model predictions against re-measured data (volume, basal area, diameter at breast height (DBH, average and top height and density from permanent sample plots using combined analysis of residual plots, bias statistics, efficiency and an innovative application of the equivalence test. For state variables, the model effectively simulated juvenile and mature stages of stand development for both pure and mixed species stands of aspen and white spruce in Alberta. MGM overestimates increment in older stands likely due to age-related pathology and weather-related stand damage. We identified underestimates of deciduous density and volume in Saskatchewan. MGM performs well for increment in postharvest stands less than 30 years of age. These results illustrate the comprehensive application of validation metrics to evaluate a complex model, and provide support for the use of MGM in management planning.

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

    Institute of Scientific and Technical Information of China (English)

    刘兴平

    2014-01-01

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

  6. Model Driven Development of Data Sensitive Systems

    DEFF Research Database (Denmark)

    Olsen, Petur

    2014-01-01

    Model-driven development strives to use formal artifacts during the development process. Formal artifacts enables automatic analyses of some aspects of the system under development. This serves to increase the understanding of the (intended) behavior of the system as well as increasing error...... to the values of variables. This theses strives to improve model-driven development of such data-sensitive systems. This is done by addressing three research questions. In the first we combine state-based modeling and abstract interpretation, in order to ease modeling of data-sensitive systems, while allowing...... efficient model-checking and model-based testing. In the second we develop automatic abstraction learning used together with model learning, in order to allow fully automatic learning of data-sensitive systems to allow learning of larger systems. In the third we develop an approach for modeling and model...

  7. Economic Development and "Indian Model"

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Dao: Early this year, there are many relevant reports on India's catching up from behind in economic development. It is reported that India and China will be the two engines to drive world economic development.

  8. 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

  9. Curriculum Development: A Philosophical Model.

    Science.gov (United States)

    Bruening, William H.

    Presenting models based on the philosophies of Carl Rogers, John Dewey, Erich Fromm, and Jean-Paul Sartre, this paper proposes a philosophical approach to education and concludes with pragmatic suggestions concerning teaching based on a fully-functioning-person model. The fully-functioning person is characterized as being open to experience,…

  10. A View of Earth System Model Development

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tianjun; YU Yongqiang; WANG Bin

    2009-01-01

    This paper gives a definition of earth system model and shows three development phases of it, including physical climate system model, earth climate system model, and earth system model, based on an inves-tigation of climate system models in the world. It provides an expatiation on the strategic significance of future development of earth system model, an introduction of some representative scientific research plans on development of earth system model home and abroad, and a review of its status and trends based on the models of the fourth assessment report (AR4) of the Intergovernmental Panel on Climate Change (IPCC).Some suggestions on future development of earth system model in China are given, which are expected to be helpful to advance the development.

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

    Institute of Scientific and Technical Information of China (English)

    赵琛琛

    2003-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    刘呈军

    2013-01-01

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

  13. El Paso's Organizational Development Model

    Science.gov (United States)

    de los Santos, Gilberto

    1975-01-01

    The success of El Paso Community College (Texas) is attributed to its early definition of instructional thrusts including: systematizing and individualizing instruction; increasing awareness, sensitivity, and appreciation of the culture of the students; development of staff bilingual capabilities; development of staff teams versed in management by…

  14. Good governance, new development model

    Directory of Open Access Journals (Sweden)

    Sanjar Salajeghe

    2014-07-01

    Full Text Available Today’s world, which is called ultra-modern world, develops special political, cultural, social and economic requirements and necessities; whereby new relationship between state and nations is required. In the past, state played important role at develop or produce services or goods, Today’s state relationship and other departments will provide Possibility of developing. For this reason, extensive efforts have been made to achieve suitable pattern of development with focus on sustainable development, so structural system and relationship between departments have been surveyed. Good governance pattern focus on accountability, Consensus-oriented, partnership, law-oriented, efficiency, clarity, responsibility and justice and designs a modern system according to interaction between triple departments of state, private and civil which Latent abilities and talents in the society are used to present effective public services, reinforce effective civil Institution and economic growth in collaboration with economic department.

  15. Development of a technoeconomic model

    DEFF Research Database (Denmark)

    Adjin, Daniel Michael Okwabi; Tadayoni, Reza

    2011-01-01

    In this article, we discuss the key technical features to be considered for developing and deploying intelligent transportation systems (ITSs) in developing countries. The empirical data are taken from a detailed case study of ITS deployment in Ghana. The methodology used for data collection...... included interviews and surveys-face-to-face discussions and questionnaires. The results show that deployment of intelligent vehicle tracking technology (IVTT) will address the problems of inefficiencies experienced in the Ghanaian road transport haulage tracking industry. Research for ITS development...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-02-01

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

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

    Science.gov (United States)

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

    2013-04-01

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

  18. Aspen Plus软件在工业上的应用

    Institute of Scientific and Technical Information of China (English)

    牛毓

    2014-01-01

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

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

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2007-11-01

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

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Bobette E Jones

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

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

    Science.gov (United States)

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

    2013-01-01

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

  4. Effect of Small Aspen Clearcuts on Water Yield and Water Quality

    OpenAIRE

    United States Department of Agriculture, Forest Service

    1984-01-01

    Streamflow and water quality were monitored in a paired watershed study involving the removal of 20 percent of the aspen (on 13 percent of the area) in five small clearcuts from a 217-acre (88-ha) catchment. There were no significant changes in peak flow, timing, or annual yield during the 4 years of posttreatment monitoring. Significant changes in pH, calcium, magnesium, and nitrates in the snowmelt streamflow from ephemeral subdrainages occurred the second year after cutting. At least so...

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

    OpenAIRE

    N. M. Nazarenko; I. M. Loza

    2010-01-01

    Conducted analysis of forest vegetation has allowed selecting and specifying classification and typological units of the aspen-and-birch separated small woods, which have statistically significant difference of ecotopic and coenotic parameters. Those parameters of studied forest ecosystems are characterised. Existence of the lines of hygrogenic and edaphogenic substitution, and succession rows are described. Phytoindication description of ecological factors’ pivotal conditions is presented. D...

  6. A One-Dimensional (1-D) Three-Region Model for a Bubbling Fluidized-Bed Adsorber

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Andrew; Miller, David C.

    2012-01-01

    A general one-dimensional (1-D), three-region model for a bubbling fluidized-bed adsorber with internal heat exchangers has been developed. The model can predict the hydrodynamics of the bed and provides axial profiles for all temperatures, concentrations, and velocities. The model is computationally fast and flexible and allows for any system of adsorption and desorption reactions to be modeled, making the model applicable to any adsorption process. The model has been implemented in both gPROMS and Aspen Custom Modeler, and the behavior of the model has been verified.

  7. Aspen-Plus模拟在氟化工中的应用

    Institute of Scientific and Technical Information of China (English)

    谢青

    2015-01-01

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

  8. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Eric C. Xu; Yajun Zhou

    2004-01-01

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

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

    Science.gov (United States)

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

    2016-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

    EricC.Xu; YajunZhou

    2004-01-01

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

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

    Science.gov (United States)

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

    2016-10-01

    Drought induces an increase in a tree's vulnerability to a loss of its hydraulic conductivity in many tree species, including two common in western Canada, trembling aspen (Populus tremuloides) and balsam poplar (Populus balsamifera). Termed 'cavitation fatigue' or 'air-seeding fatigue', the mechanism of this phenomenon is not well understood, but hypothesized to be a result of damage to xylem pit membranes. To examine the validity of this hypothesis, the effect of drought on the porosity of pit membranes in aspen and balsam poplar was investigated. Controlled drought and bench dehydration treatments were used to induce fatigue and scanning electron microscopy (SEM) was used to image pit membranes for relative porosity evaluations from air-dried samples after ethanol dehydration. A significant increase in the diameter of the largest pore was found in the drought and dehydration treatments of aspen, while an increase in the percentage of porous pit membranes was found in the dehydration treatments of both species. Additionally, the location of the largest pore per pit membrane was observed to tend toward the periphery of the membrane. PMID:27342227

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

    Directory of Open Access Journals (Sweden)

    Duygu Kocaefe

    2008-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Behzad Bazyar

    2011-12-01

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

  15. Developing Integrated Care: Towards a development model for integrated care

    OpenAIRE

    Minkman, Mirella M.N

    2012-01-01

    textabstractThe thesis adresses the phenomenon of integrated care. The implementation of integrated care for patients with a stroke or dementia is studied. Because a generic quality management model for integrated care is lacking, the study works towards building a development model for integrated care. Based on a systematic approach in which a literature study, a delphi study, a concept mapping study and questionnaire research are combined, a development model for integrated care is created....

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

    Institute of Scientific and Technical Information of China (English)

    张亮

    2015-01-01

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

  17. Toy models of developed turbulence

    Directory of Open Access Journals (Sweden)

    M.Hnatich

    2005-01-01

    Full Text Available We have investigated the advection of a passive scalar quantity by incompressible helical turbulent flow within the framework of extended Kraichnan model. Turbulent fluctuations of velocity field are assumed to have the Gaussian statistics with zero mean and defined noise with finite time-correlation. Actual calculations have been done up to two-loop approximation within the framework of field-theoretic renormalization group approach. It turned out that space parity violation (helicity of turbulent environment does not affect anomalous scaling which is a peculiar attribute of the corresponding model without helicity. However, stability of asymptotic regimes, where anomalous scaling takes place, strongly depends on the amount of helicity. Moreover, helicity gives rise to the turbulent diffusivity, which has been calculated in one-loop approximation.

  18. Requirements for Model Development Environments

    OpenAIRE

    Balci, Osman

    1983-01-01

    This paper deals with the initial phase of our ongoing research project on the Definition of a Discrete Event Simulation MDE which started on 1 June 1983. The first phase of the rapid prototyping approach we are using in designing the MDE involves the requirements specification. A literature review revealed eleven current problems in modeling. To address these problems, a MDE was identified as composed of four layers: (1) hardware and operating system, (2) kernel MDE, (3) minimal MDE, and...

  19. DSN RFI susceptibility models development program overview

    Science.gov (United States)

    Sue, M. K.

    1982-01-01

    The RFI model development described intended to provide an understanding of the interference susceptibility of DSN receivers. An overview of interference types and effects, analytic modelling and experimental verification is presented.

  20. Maturity Models Development in IS Research

    DEFF Research Database (Denmark)

    Lasrado, Lester Allan; Vatrapu, Ravi; Andersen, Kim Normann

    2015-01-01

    Maturity models are widespread in IS research and in particular, IT practitioner communities. However, theoretically sound, methodologically rigorous and empirically validated maturity models are quite rare. This literature review paper focuses on the challenges faced during the development...... literature reveals that researchers have primarily focused on developing new maturity models pertaining to domain-specific problems and/or new enterprise technologies. We find rampant re-use of the design structure of widely adopted models such as Nolan’s Stage of Growth Model, Crosby’s Grid, and Capability...... of maturity models. Specifically, it explores maturity models literature in IS and standard guidelines, if any to develop maturity models, challenges identified and solutions proposed. Our systematic literature review of IS publications revealed over hundred and fifty articles on maturity models. Extant...

  1. Nucleation and condensation model development

    Energy Technology Data Exchange (ETDEWEB)

    Fry, H.; Lyman, J.; Breshears, D.; Zerkle, D.; Wilson, C.; Hewitt, C.; Gallegos, D.

    1996-09-01

    This is a final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The purpose of this project was to bring to maturity a theoretical and experimental capability of the Laboratory to perform basic research in nucleation and condensation of water vapor. This report provides a general description of this capability and summarizes specific work in two areas: development and use of a combustive flow facility (CFF) to measure water monomer depletion in a supersonic nozzle and nucleation pulse experiments for investigation of transport effects on water droplet growth dynamics. The later work was performed in collaboration with Dr. Wehrner Strey in Goettingen, Germany. Preliminary water absorption data from the CFF experiment are presented. The nucleation pulse data is described along with an analysis that shows under the condition of the experiment the growth rate of water droplets is limited by monomer diffusion.

  2. Modeling Energy and Development : An Evaluation of Models and Concepts

    NARCIS (Netherlands)

    Ruijven, Bas van; Urban, Frauke; Benders, René M.J.; Moll, Henri C.; Sluijs, Jeroen P. van der; Vries, Bert de; Vuuren, Detlef P. van

    2008-01-01

    Most global energy models are developed by institutes from developed countries focusing primarily oil issues that are important in industrialized countries. Evaluation of the results for Asia of the IPCC/SRES models shows that broad concepts of energy and development. the energy ladder and the envir

  3. Developing Fast and Reliable Flood Models

    DEFF Research Database (Denmark)

    Thrysøe, Cecilie; Toke, Jens; Borup, Morten;

    2016-01-01

    State-of-the-art flood modelling in urban areas are based on distributed physically based models. However, their usage is impeded by high computational demands and numerical instabilities, which make calculations both difficult and time consuming. To address these challenges we develop and test...... is modelled by response surface surrogates, which are empirical data driven models. These are trained using the volume-discharge relations by piecewise linear functions. (ii) The surface flooding is modelled by lower-fidelity physically based surrogates, which are based on surface depressions and flow paths...... a cheaper-to-run surrogate model, which aims to emulate the response of an original model. The surrogate model is set up by lumping the original model into compartments. These are confined areas in which the volume is modelled by surrogates. We develop two types of surrogates: (i) The drainage system...

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

    Institute of Scientific and Technical Information of China (English)

    王磊; 李书珍; 刘卫民

    2012-01-01

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

  5. Faculty Development Using the Situational Leadership Model.

    Science.gov (United States)

    Shaner, Michael C.

    1995-01-01

    The situational leadership model developed by Hersey and Blanchard is described, and the task-specific model is then applied to the four primary tasks of college faculty--teaching, research, community service, and institutional service. The model combines directive and supportive behavior as they are reflected in four distinctive leadership…

  6. The Nomad Model: Theory, Developments and Applications

    NARCIS (Netherlands)

    Campanella, M.; Hoogendoorn, S.P.; Daamen, W.

    2014-01-01

    This paper presents details of the developments of the Nomad model after being introduced more than 12 years ago. The model is derived from a normative theory of pedestrian behavior making it unique under microscopic models. Nomad has been successfully applied in several cases indicating that it ful

  7. Continuous Competence Development Model for Teacher Teams

    DEFF Research Database (Denmark)

    Weitze, Charlotte Lærke

    2014-01-01

    "This paper presents the development of the IT‐Pedagogical Think Tank for Teacher Teams (ITP4T), a continuous competence development model. The model was co‐designed following a design‐based research approach with teachers from VUC Storstrøm’s (VUC) Global Classroom (GC), an innovative hybrid...... to create their own continuous competence development. This article describes how and why the different components of the model were developed in response to the teachers’ challenges. Such challenges included lack of time, competence and support from the educational organisation to innovate learning design...

  8. Animal models of tuberculosis for vaccine development.

    Science.gov (United States)

    Gupta, U D; Katoch, V M

    2009-01-01

    Animal models for testing different vaccine candidates have been developed since a long time for studying tuberculosis. Mice, guinea pigs and rabbits are animals most frequently used. Each model has its own merits for studying human tuberculosis, and none completely mimics the human disease. Different animal models are being used depending upon the availability of the space, trained manpower as well as other resources. Efforts should continue to develop a vaccine which can replace/outperform the presently available vaccine BCG. PMID:19287053

  9. Developing Integrated Care: Towards a development model for integrated care

    NARCIS (Netherlands)

    M.M.N. Minkman (Mirella)

    2012-01-01

    textabstractThe thesis adresses the phenomenon of integrated care. The implementation of integrated care for patients with a stroke or dementia is studied. Because a generic quality management model for integrated care is lacking, the study works towards building a development model for integrated c

  10. A Career Roles Model of Career Development

    Science.gov (United States)

    Hoekstra, Hans A.

    2011-01-01

    Career development is described as the interactive progression of internal career identity formation and the growth of external career significance. Argued is the need for a content model of career development where the field is dominated by process theories. A theory is put forward of career development crystallizing in the acquisition of career…

  11. An Aristotelian Model of Moral Development

    Science.gov (United States)

    Sanderse, Wouter

    2015-01-01

    Despite the Aristotelian renaissance in the philosophy of education, the development of virtue has not received much attention. This is unfortunate, because an attempt to draft an Aristotelian model of moral development can help philosophers to evaluate the contribution Aristotelian virtue ethics can make to our understanding of moral development,…

  12. Aspen Plus与Visual C++混合编程在化工模拟中的应用%Application of Mixed Programming Based on Aspen Plus and Visual C++ in Chemical Simulation

    Institute of Scientific and Technical Information of China (English)

    蔡振兴

    2014-01-01

    化工过程模拟软件Aspen Plus在化工流程的设计、校核方面得到了广泛的应用,显著提高了化工工艺流程设计、校核的效率和水平.Aspen Plus支持ActiveX自动控制技术,并符合CAPE-OPEN接口标准.借助Visual C++编程环境,实现了对Aspen Plus数据库的调用、单元模块的开发、以及与水力学软件的集成.

  13. Development of a comprehensive weld process model

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, B.; Zacharia, T.; Paul, A.

    1997-05-01

    This cooperative research and development agreement (CRADA) between Concurrent Technologies Corporation (CTC) and Lockheed Martin Energy Systems (LMES) combines CTC`s expertise in the welding area and that of LMES to develop computer models and simulation software for welding processes. This development is of significant impact to the industry, including materials producers and fabricators. The main thrust of the research effort was to develop a comprehensive welding simulation methodology. A substantial amount of work has been done by several researchers to numerically model several welding processes. The primary drawback of most of the existing models is the lack of sound linkages between the mechanistic aspects (e.g., heat transfer, fluid flow, and residual stress) and the metallurgical aspects (e.g., microstructure development and control). A comprehensive numerical model which can be used to elucidate the effect of welding parameters/conditions on the temperature distribution, weld pool shape and size, solidification behavior, and microstructure development, as well as stresses and distortion, does not exist. It was therefore imperative to develop a comprehensive model which would predict all of the above phenomena during welding. The CRADA built upon an already existing three-dimensional (3-D) welding simulation model which was developed by LMES which is capable of predicting weld pool shape and the temperature history in 3-d single-pass welds. However, the model does not account for multipass welds, microstructural evolution, distortion and residual stresses. Additionally, the model requires large resources of computing time, which limits its use for practical applications. To overcome this, CTC and LMES have developed through this CRADA the comprehensive welding simulation model described above.

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

    Science.gov (United States)

    Niinemets, Ülo; Sun, Zhihong; Talts, Eero

    2015-12-01

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

  15. 运用ASPEN B-JAC 设计管壳式换热器%Design and Optimize Tube/Shell Heat Exchanger by Aspen B-jac

    Institute of Scientific and Technical Information of China (English)

    周奇

    2010-01-01

    描述了运用ASPEN B-JAC换热器计算软件进行管壳式换热器设计的步骤,讨论了换热器管程壳程优化设计的要点以及利用ASPEN B-JAC进行换热器设计优化过程中应注意的问题,为管壳式换热器的优化设计提供了参考.

  16. Heterozygosity, gender, and the growth-defense trade-off in quaking aspen.

    Science.gov (United States)

    Cole, Christopher T; Stevens, Michael T; Anderson, Jon E; Lindroth, Richard L

    2016-06-01

    Although plant growth is generally recognized to be influenced by allocation to defense, genetic background (e.g., inbreeding), and gender, rarely have those factors been addressed collectively. In quaking aspen (Populus tremuloides Michx.), phenolic glycosides (PGs) and condensed tannins (CTs) constitute up to 30 % of leaf dry weight. To quantify the allocation cost of this chemical defense, we measured growth, defense chemistry, and individual heterozygosity (H obs at 16 microsatellite loci) for male and female trees in both controlled and natural environments. The controlled environment consisted of 12 juvenile genets grown for 3 years in a common garden, with replication. The natural environment consisted of 51 mature genets in wild populations, from which we sampled multiple ramets (trees) per genet. Concentrations of PGs and CTs were negatively correlated. PGs were uncorrelated with growth, but CT production represented a major cost. Across the range of CT levels found in wild-grown trees, growth rates varied by 2.6-fold, such that a 10 % increase in CT concentration occurred with a 38.5 % decrease in growth. H obs had a marked effect on aspen growth: for wild trees, a 10 % increase in H obs corresponded to a 12.5 % increase in growth. In wild trees, this CT effect was significant only in females, in which reproduction seems to exacerbate the cost of defense, while the H obs effect was significant only in males. Despite the lower growth rate of low-H obs trees, their higher CT levels may improve survival, which could account for the deficit of heterozygotes repeatedly found in natural aspen populations. PMID:26886130

  17. Mercury in Red Aspen Boletes (Leccinum aurantiacum) mushrooms and the soils.

    Science.gov (United States)

    Falandysz, Jerzy; Kowalewska, Izabela; Nnorom, Innocent C; Drewnowska, Małgorzata; Jarzyńska, Grażyna

    2012-01-01

    This communication reports data on the mercury contents of Red Aspen Boletes (Leccinum aurantiacum) mushrooms and the forest soils substrate layer (0-10 cm) underneath the fruit bodies collected from nine spatially distant sites across Poland. Total Hg concentration in soil substrate in seven of the nine sites studied varied from 0.0078 ± 0.0012 to 0.028 ± 0.007 μg/g dry weight (dw) and this could be considered baseline concentrations for uncontaminated forest soils in Poland. The arithmetic mean of mercury in Red Aspen Bolete caps varied, depending on the site from 0.27 ± 0.07 to 1.3 ± 0.6 μg/g dw. The lowest Hg contents in soil (0.011 ± 0.006 μg/g and 0.009 ± 0.002 μg/g) were observed for the sites of Wandalin and Opole Lubelskie (from Lubelska Upland region) with the corresponding highest bioconcentration factor (BCF) values of 130 ± 66 and 110 ± 13 for the mushroom caps and 58 ± 29 and 64 ± 8 for the stipes, respectively. The BCF values in caps showed a downward trend with increasing mercury content of soil. A meal of 300 g of fresh caps of Red Aspen Bolete from Aleksandrów Kujawski region could expose a consumer to 8.1 μg Hg, while this will be 39 μg at the Lubelska Upland amounting to 39 and 186 % of daily Hg reference dose, respectively.

  18. Aspen height, stem-girth and survivorship in an area of high ungulate use

    Science.gov (United States)

    Keigley, R.B.; Frisina, M.R.

    2008-01-01

    An increase in ungulate population size potentially exposes aspen suckers, saplings, and trees to increased use. This study examined how stem height and girth influenced the selection of stems by ungulates for browsing, rubbing, and gnawing, and reconstructed the history of ungulate use for the study area. Transects were run through each of three aspen clones growing in southwestern Montana to determine height, circumference, and the surface area from which bark was totally and partially removed by rubbing and gnawing. Stems 20-250 cm tall were browsed. Stems 2-13 cm diameter were preferentially selected for rubbing and gnawing. The area of totally removed bark on dead saplings was twice the area of removed bark on live stems of similar diameter, suggesting that bark removal played a major role in the death of some stems. Based on an analysis of stem height and age, ungulate browsing was inferred to have increased from a light-to-moderate level to an intense level in 1991. The depth of scars was used to date scarring events. An increase in rubbing and gnawing was determined to have occurred about 1985. We concluded that elk were primarily responsible for the observed impacts. The combined effect of rubbing, gnawing, and browsing affects a broader span of ages compared to the effect of browsing alone. If prescribed fire is used to rejuvenate aspen stands, the resulting young stems should be protected from heavy browsing, rubbing and gnawing until they reach about 13 cm diameter and have grown out of the browse zone.

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

    Science.gov (United States)

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

    2012-06-01

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

  20. Heterozygosity, gender, and the growth-defense trade-off in quaking aspen.

    Science.gov (United States)

    Cole, Christopher T; Stevens, Michael T; Anderson, Jon E; Lindroth, Richard L

    2016-06-01

    Although plant growth is generally recognized to be influenced by allocation to defense, genetic background (e.g., inbreeding), and gender, rarely have those factors been addressed collectively. In quaking aspen (Populus tremuloides Michx.), phenolic glycosides (PGs) and condensed tannins (CTs) constitute up to 30 % of leaf dry weight. To quantify the allocation cost of this chemical defense, we measured growth, defense chemistry, and individual heterozygosity (H obs at 16 microsatellite loci) for male and female trees in both controlled and natural environments. The controlled environment consisted of 12 juvenile genets grown for 3 years in a common garden, with replication. The natural environment consisted of 51 mature genets in wild populations, from which we sampled multiple ramets (trees) per genet. Concentrations of PGs and CTs were negatively correlated. PGs were uncorrelated with growth, but CT production represented a major cost. Across the range of CT levels found in wild-grown trees, growth rates varied by 2.6-fold, such that a 10 % increase in CT concentration occurred with a 38.5 % decrease in growth. H obs had a marked effect on aspen growth: for wild trees, a 10 % increase in H obs corresponded to a 12.5 % increase in growth. In wild trees, this CT effect was significant only in females, in which reproduction seems to exacerbate the cost of defense, while the H obs effect was significant only in males. Despite the lower growth rate of low-H obs trees, their higher CT levels may improve survival, which could account for the deficit of heterozygotes repeatedly found in natural aspen populations.

  1. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    Science.gov (United States)

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.

  2. Aspen Plus在化工设计物料衡算中的应用分析

    Institute of Scientific and Technical Information of China (English)

    茅慧

    2015-01-01

    化工领域中最关键的基础内容就是化工设计,随着社会的进步和科学技术的发展,传统的化工设计方式逐渐被Aspen Plus软件所替代,在化工设计领域中发挥着重要作用.本文主要阐述了Aspen Plus的概念,并对其在化工设计发挥的作用进行探究,分析了Aspen Plus在化工设计物料衡算中的应用,以期更加透彻的分析化工过程连续生产时的物料衡算,进一步提高化工设计效果.

  3. Average-passage flow model development

    Science.gov (United States)

    Adamczyk, John J.; Celestina, Mark L.; Beach, Tim A.; Kirtley, Kevin; Barnett, Mark

    1989-01-01

    A 3-D model was developed for simulating multistage turbomachinery flows using supercomputers. This average passage flow model described the time averaged flow field within a typical passage of a bladed wheel within a multistage configuration. To date, a number of inviscid simulations were executed to assess the resolution capabilities of the model. Recently, the viscous terms associated with the average passage model were incorporated into the inviscid computer code along with an algebraic turbulence model. A simulation of a stage-and-one-half, low speed turbine was executed. The results of this simulation, including a comparison with experimental data, is discussed.

  4. Developing a Domain Model for Relay Circuits

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth

    2009-01-01

    In this paper we stepwise develop a domain model for relay circuits as used in railway control systems. First we provide an abstract, property-oriented model of networks consisting of components that can be glued together with connectors. This model is strongly inspired by a network model for...... railways madeby Bjørner et.al., however our model is more general: the components can be of any kind and can later be refined to e.g. railway components or circuit components. Then we show how the abstract network model can be refined into an explicit model for relay circuits. The circuit model describes...... defined, checked to be legal, and the reaction to an input can be simulated....

  5. Developing Innovative Business Models in Social Ventures

    OpenAIRE

    Jokela, Päivi; Elo, Maria

    2015-01-01

    Social ventures represent a new type of organization that aim to create sustainable social value, such as promoting the well-being of communities and their existence is based on developing solutions to tackle complex social problems. Developing a suitable business model for a social venture is crucial because the right model with a sustainable value offering in its core can support the venture and direct it toward self-sustainability and competitiveness. Research on social...

  6. The development of a sustainable development model framework

    International Nuclear Information System (INIS)

    The emergence of the 'sustainable development' concept as a response to the mining of natural resources for the benefit of multinational corporations has advanced the cause of long-term environmental management. A sustainable development model (SDM) framework that is inclusive of the 'whole' natural environment is presented to illustrate the integration of the sustainable development of the 'whole' ecosystem. The ecosystem approach is an inclusive framework that covers the natural environment relevant futures and constraints. These are dynamically interconnected and constitute the determinates of resources development component of the SDM. The second component of the SDM framework is the resources development patterns, i.e., the use of land, water, and atmospheric resources. All of these patterns include practices that utilize environmental resources to achieve a predefined outcome producing waste and by-products that require disposal into the environment. The water quality management practices represent the third component of the framework. These practices are governed by standards, limitations and available disposal means subject to quantity and quality permits. These interconnected standards, practices and permits shape the resulting environmental quality of the ecosystem under consideration. A fourth component, environmental indicators, of the SDM framework provides a measure of the ecosystem productivity and status that may differ based on societal values and culture. The four components of the SDM are interwoven into an outcome assessment process to form the management and feedback models. The concept of Sustainable Development is expressed in the management model as an objective function subject to desired constraints imposing the required bounds for achieving ecosystem sustainability. The development of the objective function and constrains requires monetary values for ecosystem functions, resources development activities and environmental cost. The

  7. Nanocrystalline cellulose from aspen kraft pulp and its application in deinked pulp.

    Science.gov (United States)

    Xu, Qinghua; Gao, Yang; Qin, Menghua; Wu, Kaili; Fu, Yingjuan; Zhao, Jian

    2013-09-01

    Nanocrystalline cellulose (NCC) isolated from bleached aspen kraft pulp was characterized, and its application as pulp strengthening additive and retention aid was investigated. Results showed that NCC with high crystallinity of more than 80% can be obtained using 64 wt% sulfuric acid. The structure of nanocrystalline cellulose is parallelepiped rod-like, and their cross-sectional dimension is in the nanometer range with a high aspect ratio. The formation of microparticle retention systems during the application of NCC together with cationic polyacrylamide and cationic starch in deinked pulp was able to further improve pulp retention and strength properties without negative influence on the drainage.

  8. 甲醇合成过程的Aspen模拟%Aspen Analog of Methanol Synthesis Process

    Institute of Scientific and Technical Information of China (English)

    孟庆军

    2005-01-01

    通过Aspen-Plus工具,采用合成动力学方程对甲醇合成流程进行了全流程模拟,分析了模拟计算结果.从循环气量、合成压力、冷却水温、合成塔进口温度、合成塔结构、催化剂装填量等方面论述了操作条件和反应器尺寸的变化对合成回路的影响.

  9. MODELS OF TOURIST DEVELOPMENT IN THE CONTEXT OF REGIONAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Borma Afrodita

    2012-07-01

    Full Text Available Third year PhD candidate at the University of Oradea, under the guidance of Professor Mrs. Alina Bădulescu in the doctoral research project entitled: "Doctoral studies and Ph.D. candidates for competitive research on a knowledge based society", a co-financed project by the European Social Fund through the Sectoral Operational Program for Human Resources Development 2007 - 2013, Priority Axis 1. "Education and training in support for growth and development of a knowledge based society" I chose to present this subject in order to demonstrate the connection that exists between tourism and regional development. Having as research topic "Tourism and development in the Euro regional context” I felt it would be appropriate to devote a subchapter in presenting the impact of tourism in regional development. Thus I have analysed a number of specialised papers found at national and international level in order to achieve a synthesis on the approached topic. Authors such as Williams and Shaw (1991, Sharma (2004, Keskin and Cansiz (2010 were concerned with presenting the positive aspects of tourism in regional development. Condes (2004 presents on one hand the secrets regarding success in matter of tourist development, and on the other side he presents the possible risks that follow the development of tourism in a country / region (Condes 2004. Following the gathered information we found that indeed tourism plays an important role in regional development. The used research methodology consisted in using specialised literature in order to identify some models that illustrate the potential success of tourism in regional development. The space-temporal development model of tourism proposed by Opperman (1993, although it was developed at national level represents a useful tool in illustrating the potential success of tourism in regional development. Miossec's model (Sharma 2004:300 describes the structural evolution of touristic regions in

  10. Development of osteoporosis animal model using micropigs

    OpenAIRE

    Kim, Sang-Woo; Kim, Kyoung-Shim; Solis, Chester D.; Lee, Myeong-Seop; Hyun, Byung-Hwa

    2013-01-01

    Osteoporosis is a known major health problem and a serious disease of the bone, there has been a great need to develop more and newer animal models for this disease. Among animal models used for testing drug efficacy, the minipig model has become useful and effective due to its close similarity with humans (validity), particularly with the pharmacokinetics of compounds via subcutaneous administration, the structure and function of the organs, the morphology of bone and the overall metabolic n...

  11. Developing modelling lenses among practicing teachers

    Science.gov (United States)

    Awawdeh Shahbari, Juhaina; Tabach, Michal

    2016-07-01

    Growing awareness of the importance of modelling activities in mathematics education has raised the question of whether teachers are prepared to facilitate the engagement of students in such activities. The current study investigates the effects of how teachers cope with modelling activities in developing their abilities to identify modelling cycles. The research was conducted among 34 practicing teachers studying for master's degrees at a college of education. The data were collected from two reports and one reflection provided by the participants about a modelling activity conducted by a group of five sixth-grade students. The first report was submitted before the participants themselves dealt with the modelling activities, while the second report and the reflection were submitted after their participation in the modelling activities. The findings indicate that prior to participating in the activity most of the teachers described the students' participation in modelling activity as a linear process. The participating teachers noticed the final mathematical model and the mathematical results obtained from applying the model, but most of them ignored the realistic results, the validating process and the cyclical nature of the mathematical model's progress. However, after the practicing teachers participated in modelling activities as learners, their reports indicated that most were able to recognize all the modelling phases and to distinguish the cyclical processes of the progress of the mathematical models. Moreover, according to the analyses of the reflections, the participating teachers are aware of the changes in their descriptions.

  12. Suitability of Modern Software Development Methodologies for Model Driven Development

    Directory of Open Access Journals (Sweden)

    Ruben Picek

    2009-12-01

    Full Text Available As an answer to today’s growing challenges in software industry, wide spectrum of new approaches of software development has occurred. One prominent direction is currently most promising software development paradigm called Model Driven Development (MDD. Despite a lot of skepticism and problems, MDD paradigm is being used and improved to accomplish many inherent potential benefits. In the methodological approach of software development it is necessary to use some kind of development process. Modern methodologies can be classified into two main categories: formal or heavyweight and agile or lightweight. But when it is a question about MDD and development process for MDD, currently known methodologies are very poor or better said they don't have any explanation of MDD process. As the result of research, in this paper, author examines the possibilities of using existing modern software methodologies in context of MDD paradigm.

  13. 采用Aspen Plus设计计算蒸汽减温减压系统

    Institute of Scientific and Technical Information of China (English)

    王潇; 刘明; 夏红勋

    2015-01-01

    采用Aspen Plus设计计算蒸汽减温减压系统,并将所得数据与现场实际装置的运行情况相比较。结果表明,采用Aspen Plus模拟计算的结果与生产装置的运行参数和物性手册的数据相一致,在工程允许误差范围之内。

  14. BUILDING A SUSTAINABLE REGION ECONOMIC DEVELOPMENT MODEL

    Directory of Open Access Journals (Sweden)

    Pshunetlev A. A.

    2014-09-01

    Full Text Available The article contains basic assumptions of the region sustainable economic development model, which can be used to gain new knowledge about economic processes, contribute to the stability of the regional development, as well as serve as an educational tool in the study of relevant disciplines

  15. Conceptualizing Evolving Models of Educational Development

    Science.gov (United States)

    Fraser, Kym; Gosling, David; Sorcinelli, Mary Deane

    2010-01-01

    Educational development, which the authors use to refer to the field of professional and strategic development associated with university and college learning and teaching, can be described in many ways by referring to its different aspects. In this article the authors endeavor to categorize many of the models that have been used to describe…

  16. A career roles model of career development

    NARCIS (Netherlands)

    Hoekstra, Hans A.

    2011-01-01

    Career development is described as the interactive progression of internal career identity formation and the growth of external career significance. Argued is the need for a content model of career development where the field is dominated by process theories. A theory is put forward of career develo

  17. A Generic Modeling Process to Support Functional Fault Model Development

    Science.gov (United States)

    Maul, William A.; Hemminger, Joseph A.; Oostdyk, Rebecca; Bis, Rachael A.

    2016-01-01

    Functional fault models (FFMs) are qualitative representations of a system's failure space that are used to provide a diagnostic of the modeled system. An FFM simulates the failure effect propagation paths within a system between failure modes and observation points. These models contain a significant amount of information about the system including the design, operation and off nominal behavior. The development and verification of the models can be costly in both time and resources. In addition, models depicting similar components can be distinct, both in appearance and function, when created individually, because there are numerous ways of representing the failure space within each component. Generic application of FFMs has the advantages of software code reuse: reduction of time and resources in both development and verification, and a standard set of component models from which future system models can be generated with common appearance and diagnostic performance. This paper outlines the motivation to develop a generic modeling process for FFMs at the component level and the effort to implement that process through modeling conventions and a software tool. The implementation of this generic modeling process within a fault isolation demonstration for NASA's Advanced Ground System Maintenance (AGSM) Integrated Health Management (IHM) project is presented and the impact discussed.

  18. MODEL DRIVEN DEVELOPMENT OF ONLINE BANKING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Bresfelean Vasile Paul

    2011-07-01

    Full Text Available In case of online applications the cycle of software development varies from the routine. The online environment, the variety of users, the treatability of the mass of information created by them, the reusability and the accessibility from different devices are all factors of these systems complexity. The use of model drive approach brings several advantages that ease up the development process. Working prototypes that simplify client relationship and serve as the base of model tests can be easily made from models describing the system. These systems make possible for the banks clients to make their desired actions from anywhere. The user has the possibility of accessing information or making transactions.

  19. Development of a working Hovercraft model

    Science.gov (United States)

    Noor, S. H. Mohamed; Syam, K.; Jaafar, A. A.; Mohamad Sharif, M. F.; Ghazali, M. R.; Ibrahim, W. I.; Atan, M. F.

    2016-02-01

    This paper presents the development process to fabricate a working hovercraft model. The purpose of this study is to design and investigate of a fully functional hovercraft, based on the studies that had been done. The different designs of hovercraft model had been made and tested but only one of the models is presented in this paper. In this thesis, the weight, the thrust, the lift and the drag force of the model had been measured and the electrical and mechanical parts are also presented. The processing unit of this model is Arduino Uno by using the PSP2 (Playstation 2) as the controller. Since our prototype should be functioning on all kind of earth surface, our model also had been tested in different floor condition. They include water, grass, cement and tile. The Speed of the model is measured in every case as the respond variable, Current (I) as the manipulated variable and Voltage (V) as the constant variable.

  20. Modelling the canopy development of bambara groundnut

    DEFF Research Database (Denmark)

    Karunaratne, A.S.; Azam-Ali, S.N.; Al-Shareef, I.;

    2010-01-01

    Canopy development of bambara groundnut (Vigna subterranea (L.) Verdc) is affected by temperature stress, drought stress and photoperiod. The quantification of these documented effects by means of a suitable crop model, BAMGRO is presented in this paper. Data on canopy development from five growth...... chamber, four glasshouse and three field experiments were analyzed to calibrate and validate the BAMGRO model to produce simulations for temperature stress, drought stress and photoperiodic effect on two contrasting landraces; Uniswa Red (Swaziland) and S19-3 (Namibia). The daily initiation rate of new...... and drought stress. The leaf area expansion is calculated as a function of leaf number and individual leaf size. The canopy development of bambara groundnut is modelled (and tested) in BAMGRO model by means of leaf initiation and leaf area expansion and branching and stem production are not considered. Nash...

  1. Aspen Winter Workshop: New Directions in Neutrino Physics

    CERN Document Server

    2013-01-01

    Nearly a decade ago, a clear path forward was developed by the neutrino physics community. Exciting new results have recently come out as early steps along that path. The time is now ripe to look at new experimental ideas that have arisen and the performance of current experiments. This conference will take the current status of experiment as its launching point. We will examine new accelerator and reactor oscillation results, prospects for learning about mass hierarchy and leptonic CP violation, and potential for new physics in oscillation experiments. We will also cover the latest developments in neutrino physics, astrophysics and cosmology more broadly, including neutrinoless double beta decay, neutrino interactions, and supernovae. The emphasis of the conference will be on how new experimental techniques and theoretical ideas will impact the future directions of the field.

  2. Populus tremula (European aspen) shows no evidence of sexual dimorphism

    OpenAIRE

    Robinson, Kathryn M; Delhomme, Nicolas; Mähler, Niklas; Schiffthaler, Bastian; Önskog, Jenny; Albrectsen, Benedicte Rieber; Pär K Ingvarsson; Hvidsten, Torgeir Rhoden; Jansson, Stefan; Street, Nathaniel

    2014-01-01

    Background Evolutionary theory suggests that males and females may evolve sexually dimorphic phenotypic and biochemical traits concordant with each sex having different optimal strategies of resource investment to maximise reproductive success and fitness. Such sexual dimorphism would result in sex biased gene expression patterns in non-floral organs for autosomal genes associated with the control and development of such phenotypic traits. Results We examined morphological, biochemical and he...

  3. System model development for nuclear thermal propulsion

    International Nuclear Information System (INIS)

    A critical enabling technology in the evolutionary development of nuclear thermal propulsion (NTP) is the ability to predict the system performance under a variety of operating conditions. Since October 1991, US (DOE), (DOD) and NASA have initiated critical technology development efforts for NTP systems to be used on Space Exploration Initiative (SEI) missions to the Moon and Mars. This paper presents the strategy and progress of an interagency NASA/DOE/DOD team for NTP system modeling. It is the intent of the interagency team to develop several levels of computer programs to simulate various NTP systems. An interagency team was formed for this task to use the best capabilities available and to assure appropriate peer review. The vision and strategy of the interagency team for developing NTP system models will be discussed in this paper. A review of the progress on the Level 1 interagency model is also presented

  4. Model Development for Scientific Data Curation Education

    Directory of Open Access Journals (Sweden)

    Karon Kelly

    2013-06-01

    Full Text Available The mounting and critical need for scientific data curation professionals was the impetus for the Data Curation Education in Research Centers (DCERC program. DCERC is developing a sustainable and transferable model for educating Library and Information Science (LIS students in data curation through field experiences in research and data centers. DCERC has established and implemented a graduate research and education program bringing students into the real world of scientific data curation, where they engage with current practices and challenges, and share their developing expertise and research. The DCERC partner institutions are developing and evaluating this model with the intention of scaling the program to a larger cadre of partners and participants. This paper reports on progress in the early phases of the model development.

  5. Modeling socioeconomic status effects on language development.

    Science.gov (United States)

    Thomas, Michael S C; Forrester, Neil A; Ronald, Angelica

    2013-12-01

    Socioeconomic status (SES) is an important environmental predictor of language and cognitive development, but the causal pathways by which it operates are unclear. We used a computational model of development to explore the adequacy of manipulations of environmental information to simulate SES effects in English past-tense acquisition, in a data set provided by Bishop (2005). To our knowledge, this is the first application of computational models of development to SES. The simulations addressed 3 new challenges: (a) to combine models of development and individual differences in a single framework, (b) to expand modeling to the population level, and (c) to implement both environmental and genetic/intrinsic sources of individual differences. The model succeeded in capturing the qualitative patterns of regularity effects in both population performance and the predictive power of SES that were observed in the empirical data. The model suggested that the empirical data are best captured by relatively wider variation in learning abilities and relatively narrow variation in (and good quality of) environmental information. There were shortcomings in the model's quantitative fit, which are discussed. The model made several novel predictions, with respect to the influence of SES on delay versus giftedness, the change of SES effects over development, and the influence of SES on children of different ability levels (gene-environment interactions). The first of these predictions was that SES should reliably predict gifted performance in children but not delayed performance, and the prediction was supported by the Bishop data set. Finally, the model demonstrated limits on the inferences that can be drawn about developmental mechanisms on the basis of data from individual differences.

  6. Multicomponent aerosol dynamics model UHMA: model development and validation

    OpenAIRE

    Korhonen, H.; Lehtinen, K. E. J.; Kulmala, M.

    2004-01-01

    A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model) was developed for studies of multicomponent tropospheric aerosol particles. The model includes major aerosol microphysical processes in the atmosphere with a focus on new particle formation and growth; thus it incorporates particle coagulation and multicomponent condensation, applying a revised treatment of condensation flux onto free molecular regime particles and the activation of nanosi...

  7. Developing a Model for Continuous Professional Development by Action Research

    Science.gov (United States)

    Herbert, Susan; Rainford, Marcia

    2014-01-01

    This paper presents a case study of the work of two teacher educators with an in-service science teacher. This case study forms one cycle of a larger action research study that will eventually lead to a model of how the third-space concept for teacher professional development can be realized in natural school settings. The case study took place in…

  8. DEVELOPMENT MODEL OF UNDER DEVELOPED SMALL ISLAND IN SUMENEP

    Directory of Open Access Journals (Sweden)

    Sudarti Sudarti

    2011-09-01

    Full Text Available The purpose of this study is to build a Geographic Information System and Management Information System models of development of small islands in Sumenep. Based on the identification of economic potential there are few regions such as Nonggunong, Gayam, Ra'as, and Sapeken which have large contribution toward the rice plant production. The whole districts of the islands in Sumenep are the base of cow, horse, chicken and livestock commodities. Sapeken have significant contribution for marine fish. Giligenting, Nonggunong, Gayam, and Arjasa have large potential for brackish fish. Moreover, Gili-genting also has a great contribution for fresh fish.Keywords: Development model, under-developed area, small islandsJEL classification numbers: O13, O14

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

    Science.gov (United States)

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

    2016-07-01

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

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

    International Nuclear Information System (INIS)

    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.

  11. Kinetics model development of cocoa bean fermentation

    Science.gov (United States)

    Kresnowati, M. T. A. P.; Gunawan, Agus Yodi; Muliyadini, Winny

    2015-12-01

    Although Indonesia is one of the biggest cocoa beans producers in the world, Indonesian cocoa beans are oftenly of low quality and thereby frequently priced low in the world market. In order to improve the quality, adequate post-harvest cocoa processing techniques are required. Fermentation is the vital stage in series of cocoa beans post harvest processing which could improve the quality of cocoa beans, in particular taste, aroma, and colours. During the fermentation process, combination of microbes grow producing metabolites that serve as the precursors for cocoa beans flavour. Microbial composition and thereby their activities will affect the fermentation performance and influence the properties of cocoa beans. The correlation could be reviewed using a kinetic model that includes unstructured microbial growth, substrate utilization and metabolic product formation. The developed kinetic model could be further used to design cocoa bean fermentation process to meet the expected quality. Further the development of kinetic model of cocoa bean fermentation also serve as a good case study of mixed culture solid state fermentation, that has rarely been studied. This paper presents the development of a kinetic model for solid-state cocoa beans fermentation using an empirical approach. Series of lab scale cocoa bean fermentations, either natural fermentations without starter addition or fermentations with mixed yeast and lactic acid bacteria starter addition, were used for model parameters estimation. The results showed that cocoa beans fermentation can be modelled mathematically and the best model included substrate utilization, microbial growth, metabolites production and its transport. Although the developed model still can not explain the dynamics in microbial population, this model can sufficiently explained the observed changes in sugar concentration as well as metabolic products in the cocoa bean pulp.

  12. Development of Ensemble Model Based Water Demand Forecasting Model

    Science.gov (United States)

    Kwon, Hyun-Han; So, Byung-Jin; Kim, Seong-Hyeon; Kim, Byung-Seop

    2014-05-01

    In recent years, Smart Water Grid (SWG) concept has globally emerged over the last decade and also gained significant recognition in South Korea. Especially, there has been growing interest in water demand forecast and optimal pump operation and this has led to various studies regarding energy saving and improvement of water supply reliability. Existing water demand forecasting models are categorized into two groups in view of modeling and predicting their behavior in time series. One is to consider embedded patterns such as seasonality, periodicity and trends, and the other one is an autoregressive model that is using short memory Markovian processes (Emmanuel et al., 2012). The main disadvantage of the abovementioned model is that there is a limit to predictability of water demands of about sub-daily scale because the system is nonlinear. In this regard, this study aims to develop a nonlinear ensemble model for hourly water demand forecasting which allow us to estimate uncertainties across different model classes. The proposed model is consist of two parts. One is a multi-model scheme that is based on combination of independent prediction model. The other one is a cross validation scheme named Bagging approach introduced by Brieman (1996) to derive weighting factors corresponding to individual models. Individual forecasting models that used in this study are linear regression analysis model, polynomial regression, multivariate adaptive regression splines(MARS), SVM(support vector machine). The concepts are demonstrated through application to observed from water plant at several locations in the South Korea. Keywords: water demand, non-linear model, the ensemble forecasting model, uncertainty. Acknowledgements This subject is supported by Korea Ministry of Environment as "Projects for Developing Eco-Innovation Technologies (GT-11-G-02-001-6)

  13. Object-oriented Modular Model Library for Distillation

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang; DING Jianwan; CHEN Liping

    2013-01-01

    For modeling and simulation of distillation process,there are lots of special purpose simulators along with their model libraries,such as Aspen Plus and HYSYS.However,the models in these tools lack of flexibility and are not open to the end-user.Models developed in one tool can not be conveniently used in others because of the barriers among these simulators.In order to solve those problems,a flexible and extensible distillation system model library is constructed in this study,based on the Modelica and Modelica-supported platform MWorks,by the object-oriented technology and level progressive modeling strategy.It supports the reuse of knowledge on different granularities:physical phenomenon,unit model and system model.It is also an interface-friendly,accurate,fast PC-based and easily reusable simulation tool,which enables end-user to customize and extend the framework to add new functionality or adapt the simulation behavior as required.It also allows new models to be composed programmatically or graphically to form more complex models by invoking the existing components.A conventional air distillation column model is built and calculated using the library,and the results agree well with that simulated in Aspen Plus.

  14. Clover development during spaceflight: A model system

    Science.gov (United States)

    Guikema, James A.; Debell, Lynnette; Paulsen, Avelina; Spooner, Brian S.; Wong, Peter P.

    1994-08-01

    The development of legume root nodules was studied as a model system for the examination of gravitational effects on plant root development. In order to examine whether rhizobial association with clover roots can be achieved in microgravity, experiments were performed aboard the KC-135 parabolic aircraft and aboard the sounding rocket mission Consort 3. Binding of rhizobia to roots and the initial stages of root nodule development successfully occurred in microgravity. Seedling germination experiments were performed in the sliding block device, the Materials Dispersion Apparatus, aboard STS-37. When significant hydration of the seeds was achieved, normal rates of germination and seedling development were observed.

  15. The Aspen--Amsterdam Void Finder Comparison Project

    CERN Document Server

    Colberg, Joerg M; Foster, Caroline; Platen, Erwin; Brunino, Riccardo; Neyrinck, Mark; Basilakos, Spyros; Fairall, Anthony; Feldman, Hume; Gottloeber, Stefan; Hahn, Oliver; Hoyle, Fiona; Mueller, Volker; Nelson, Lorne; Plionis, Manolis; Porciaini, Cristiano; Shandarin, Sergei; Vogeley, Michael S; van de Weygaert, Rien

    2008-01-01

    Despite a history that dates back at least a quarter of a century studies of voids in the large--scale structure of the Universe are bedevilled by a major problem: there exist a large number of quite different void--finding algorithms, a fact that has so far got in the way of groups comparing their results without worrying about whether such a comparison in fact makes sense. Because of the recent increased interest in voids, both in very large galaxy surveys and in detailed simulations of cosmic structure formation, this situation is very unfortunate. We here present the first systematic comparison study of thirteen different void finders constructed using particles, haloes, and semi--analytical model galaxies extracted from a subvolume of the Millennium simulation. The study includes many groups that have studied voids over the past decade. We show their results and discuss their differences and agreements. As it turns out, the basic results of the various methods agree very well with each other in that they...

  16. Energy and Development. A Modelling Approach

    International Nuclear Information System (INIS)

    Rapid economic growth of developing countries like India and China implies that these countries become important actors in the global energy system. Examples of this impact are the present day oil shortages and rapidly increasing emissions of greenhouse gases. Global energy models are used to explore possible future developments of the global energy system and identify policies to prevent potential problems. Such estimations of future energy use in developing countries are very uncertain. Crucial factors in the future energy use of these regions are electrification, urbanisation and income distribution, issues that are generally not included in present day global energy models. Model simulations in this thesis show that current insight in developments in low-income regions lead to a wide range of expected energy use in 2030 of the residential and transport sectors. This is mainly caused by many different model calibration options that result from the limited data availability for model development and calibration. We developed a method to identify the impact of model calibration uncertainty on future projections. We developed a new model for residential energy use in India, in collaboration with the Indian Institute of Science. Experiments with this model show that the impact of electrification and income distribution is less univocal than often assumed. The use of fuelwood, with related health risks, can decrease rapidly if the income of poor groups increases. However, there is a trade off in terms of CO2 emissions because these groups gain access to electricity and the ownership of appliances increases. Another issue is the potential role of new technologies in developing countries: will they use the opportunities of leapfrogging? We explored the potential role of hydrogen, an energy carrier that might play a central role in a sustainable energy system. We found that hydrogen only plays a role before 2050 under very optimistic assumptions. Regional energy

  17. Application of Aspen Plus in the Practical Teaching of Chemical Technology%基于 Aspen Plus 在化工工艺学教学中的应用

    Institute of Scientific and Technical Information of China (English)

    唐新宜

    2016-01-01

    化工工艺学是一门理论与生产相结合的课程。本文讨论了化工流程模拟软件Aspen与化工工艺学教学的关系,将Aspen Plus流程模拟软件逐步引入到化工工艺学实践教学中,加深了学生对化工生产工艺的理解,并提高了学生利用工具解决实际问题的能力。引入Aspen Plus软件作为化工工艺学教学辅助工具,能使教学更接近实际生产过程,拓宽了学生的视野。%Chemical Technology is a rather practical course .The relationship between Aspen Plus software and Chemical Technology were discussed .Aspen Plus software was introduced in the teaching of Chemical Technology course to strengthen the understanding of Chemical Engineering courses and improve the hands-on and implementing ability of the students , which made the teaching closer to engineering practice and broaden the students ’visual field.

  18. 基于Aspen Plus物性分析计算甲醇水溶液凝固点%Calculation for freezing points of methanol aqueous solution based on property analysis of Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    刘光明; 王伟鹏

    2013-01-01

    探讨了气液固多相平衡的机理,利用活度系数法计算各相热力学性质,采用Aspen plus物性分析计算不同浓度的甲醇水溶液凝固点,将计算结果与手册值进行比较,结果表明:模拟计算结果与手册值较为接近,在工程误差允许的范围内,可以用Aspen plus物性分析计算甲醇水溶液凝固点.%The multiphase balance mechanism of gas,liquid and solid was discussed.The thermodynamic properties of which were calculated by activity coefficient method.The freezing points of the methanol aqueous solution with different concentrations were calculated using the properties analysis of Aspen Plus.The results show that the simulation result is much close to the manual value.Within the allowed range of engineering error,the freezing points of the methanol aqueous solution can be simulated based on properties analysis of Aspen Plus and used in the practical engineering.

  19. Reserves accumulated in non-photosynthetic organs during the previous growing season drive plant defenses and growth in aspen in the subsequent growing season.

    Science.gov (United States)

    Najar, Ahmed; Landhäusser, Simon M; Whitehill, Justin G A; Bonello, Pierluigi; Erbilgin, Nadir

    2014-01-01

    Plants store non-structural carbohydrates (NSC), nitrogen (N), as well as other macro and micronutrients, in their stems and roots; the role of these stored reserves in plant growth and defense under herbivory pressure is poorly understood, particularly in trees. Trembling aspen (Populus tremuloides) seedlings with different NSC and N reserves accumulated during the previous growing season were generated in the greenhouse. Based on NSC and N contents, seedlings were assigned to one of three reserve statuses: Low N-Low NSC, High N-Medium NSC, or High N-High NSC. In the subsequent growing season, half of the seedlings in each reserve status was subjected to defoliation by forest tent caterpillar (Malacosoma disstria) while the other half was left untreated. Following defoliation, the effect of reserves was measured on foliar chemistry (N, NSC) and caterpillar performance (larval development). Due to their importance in herbivore feeding, we also quantified concentrations of phenolic glycoside compounds in foliage. Seedlings in Low N-Low NSC reserve status contained higher amounts of induced phenolic glycosides, grew little, and supported fewer caterpillars. In contrast, aspen seedlings in High N-Medium or High NSC reserve statuses contained lower amounts of induced phenolic glycosides, grew faster, and some of the caterpillars which fed on these seedlings developed up to their fourth instar. Furthermore, multiple regression analysis indicated that foliar phenolic glycoside concentration was related to reserve chemistry (NSC, N). Overall, these results demonstrate that reserves accumulated during the previous growing season can influence tree defense and growth in the subsequent growing season. Additionally, our study concluded that the NSC/N ratio of reserves in the previous growing season represents a better measure of resources available for use in defense and growth than the foliar NSC/N ratios.

  20. SOFTWARE DEVELOPMENT MODEL FOR ETHNOBILINGUAL DICTIONARIES

    OpenAIRE

    Melchora Morales-Sánchez; Erasmo Miranda-Bojórquez

    2010-01-01

    A software development integral model for a dictionary to store and retrieve textual, visual, and most important, incorporating the audio of oral language. Taking into account both the characterization of indigenous cultural reality and the technical aspects of software construction. Such model consists of the next phases: context description, lexicographic design, computer design and multimedia, construction and tests of the application. There isn´t doubt about the influence of the contact o...

  1. Development of centrifuge modelling in geotechnics

    OpenAIRE

    J. Garnier

    2006-01-01

    In order to satisfy similitude conditions, physical modelling in the field of geotechnics requires major facilities, such as shaking tables, calibration chambers and centrifuges. The rapid expansion of centifuge modelling since the beginning of the 1980's can be explained by technological developments in computing, electronics and mechanics as well by enhanced knowledge in the areas of scaling laws, thanks to recent research work on both the properties of reconstituted soils and similitude co...

  2. 基于 Aspen Adsorption 的活性炭吸附溶液中镍离子的模拟研究%Simulation study on adsorption of nickel ion onto activated carbon from aqueous solution based on Aspen Adsorption

    Institute of Scientific and Technical Information of China (English)

    刘金昌; 曹俊雅; 刘娟; 解强

    2013-01-01

      利用 Aspen Adsorption 对活性炭吸附溶液中镍离子的过程进行模拟研究。通过静态吸附实验数据拟合、吸附等温线常数项估算,建立了实验室规模的活性炭吸附溶液中镍离子的单塔吸附模型;在设置的进料流量为0.001 m3/s、进料浓度为50 mg/m3的初始条件下,模拟计算获得了吸附塔出口液相中镍离子浓度随时间的变化和沿床层轴向的分布,并考察了进料浓度、进料流量和传质系数等对吸附过程和穿透曲线的影响。结果表明:模拟计算结果与实验结果基本吻合,模型假设、参数设置合理,研究条件下吸附床层在15000 s 后被完全穿透;随进料镍离子浓度、进料流量的增大,吸附床层的穿透曲线均前移,进料流量的影响更为显著,进料镍离子浓度由50 mg/m3增大至5000 mg/m3时,穿透时间从3500 s 提前至1500 s,而进料量由0.001 m3/s 提高到0.002 m3/s 时,穿透时间从3500 s 即提前至1700 s;传质系数≤0.1 s-1时对吸附性能影响显著。模拟研究、计算为放大试验及实际工程应用工艺参数的选择提供了依据。%  Adsorption process of nickel ion onto activated carbon from aqueous solution was simulated and studied with the aid of Aspen Adsorption. The model of a laboratory scale column for nickel adsorption was built on the basis of the experimental data fitting and the adsorption isotherm constants estimating. The nickel ion concentration at exit of adsorption column vs time curve and bed axial loading distribution of nickel ion were obtained from simulation results with the assumption of process parameters, including feed flow rate of 0.001 m3/s and feed concentration of 50 mg/m3. Also, the influences of feed concentration, feed flow rate and mass transfer coefficient on adsorption process and breakthrough curve were investigated. The results reveal that the simulated values of the model are consistent with

  3. Development of a Comprehensive Weld Process Model

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, B.; Zacharia, T.

    1997-05-01

    This cooperative research and development agreement (CRADA) between Concurrent Technologies Corporation (CTC) and Lockheed Martin Energy Systems (LMES) combines CTC's expertise in the welding area and that of LMES to develop computer models and simulation software for welding processes. This development is of significant impact to the industry, including materials producers and fabricators. The main thrust of the research effort was to develop a comprehensive welding simulation methodology. A substantial amount of work has been done by several researchers to numerically model several welding processes. The primary drawback of most of the existing models is the lack of sound linkages between the mechanistic aspects (e.g., heat transfer, fluid flow, and residual stress) and the metallurgical aspects (e.g., microstructure development and control). A comprehensive numerical model which can be used to elucidate the effect of welding parameters/conditions on the temperature distribution, weld pool shape and size, solidification behavior, and microstructure development, as well as stresses and distortion, does not exist. It was therefore imperative to develop a comprehensive model which would predict all of the above phenomena during welding. The CRADA built upon an already existing three- dimensional (3-D) welding simulation model which was developed by LMES which is capable of predicting weld pool shape and the temperature history in 3-d single-pass welds. However, the model does not account for multipass welds, microstructural evolution, distortion and residual stresses. Additionally, the model requires large resources of computing time, which limits its use for practical applications. To overcome this, CTC and LMES have developed through this CRADA the comprehensive welding simulation model described above. The following technical tasks have been accomplished as part of the CRADA. 1. The LMES welding code has been ported to the Intel Paragon parallel computer at

  4. Argonne Bubble Experiment Thermal Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-03

    This report will describe the Computational Fluid Dynamics (CFD) model that was developed to calculate the temperatures and gas volume fractions in the solution vessel during the irradiation. It is based on the model used to calculate temperatures and volume fractions in an annular vessel containing an aqueous solution of uranium . The experiment was repeated at several electron beam power levels, but the CFD analysis was performed only for the 12 kW irradiation, because this experiment came the closest to reaching a steady-state condition. The aim of the study is to compare results of the calculation with experimental measurements to determine the validity of the CFD model.

  5. A review on pilot plant development models

    International Nuclear Information System (INIS)

    After more than 30 years, MINT has been able to produce many new findings, products and processes. Some of these have been able to penetrate local and international markets. This was achieved through a systematic commercialisation program practiced in MINT with its technological chain and MINT Technology Park program. This paper will review the development process of MINT pilot plants and compare them with a few other models from other institutions in Malaysia and abroad. The advantages and disadvantages of each model are reviewed and a discussion against MINT's model is presented. (Author)

  6. Software Model Of Software-Development Process

    Science.gov (United States)

    Lin, Chi Y.; Synott, Debra J.; Levary, Reuven R.

    1990-01-01

    Collection of computer programs constitutes software tool for simulation of medium- to large-scale software-development projects. Necessary to include easily identifiable and more-readily quantifiable characteristics like costs, times, and numbers of errors. Mathematical model incorporating these and other factors of dynamics of software-development process implemented in the Software Life Cycle Simulator (SLICS) computer program. Simulates dynamics of software-development process. In combination with input and output expert software systems and knowledge-based management software system, develops information for use in managing large software-development project. Intended to aid managers in planning, managing, and controlling software-development processes by reducing uncertainties in budgets, required personnel, and schedules.

  7. Development modeling of Lucilia sericata (Diptera: Calliphoridae

    Directory of Open Access Journals (Sweden)

    Amanda Roe

    2015-03-01

    Full Text Available The relationship between insect development and temperature has been well established and has a wide range of uses, including the use of blow flies for postmortem (PMI interval estimations in death investigations. To use insects in estimating PMI, we must be able to determine the insect age at the time of discovery and backtrack to time of oviposition. Unfortunately, existing development models of forensically important insects are only linear approximations and do not take into account the curvilinear properties experienced at extreme temperatures. A series of experiments were conducted with Lucilia sericata, a forensically important blow fly species, that met the requirements needed to create statistically valid development models. Experiments were conducted over 11 temperatures (7.5 to 32.5 °C, at 2.5 °C with a 16:8 L:D cycle. Experimental units contained 20 eggs, 10 g beef liver, and 2.5 cm of pine shavings. Each life stage (egg to adult had five sampling times. Each sampling time was replicated four times, for a total of 20 measurements per life stage. For each sampling time, the cups were pulled from the chambers and the stage of each maggot was documented morphologically through posterior spiracle slits and cephalopharyngeal skeletal development. Data were normally distributed with the later larval stages (L3f, L3m having the most variation within and transitioning between stages. The biological minimum was between 7.5 °C and 10 °C, with little egg development and no egg emergence at 7.5 °C. Temperature-induced mortality was highest from 10.0 to 17.5 °C and 32.5 °C. The development data generated illustrates the advantages of large datasets in modeling Lucilia sericata development and the need for curvilinear models in describing development at environmental temperatures near the biological minima and maxima.

  8. Status report on dissolution model development

    International Nuclear Information System (INIS)

    The computer program PROTOCOL models the dissolution reactions of chemical species in water. It is being developed particularly to study the dissolution of proposed nuclear waste forms and related phases. Experimentally derived leaching rate functions are coupled to thermochemical equilibrium calculations and water flow rates. The program has been developed over a period of years. This report describes improvements that have been done in the past year

  9. Development of a simplified biofilm model

    Science.gov (United States)

    Sarkar, Sushovan; Mazumder, Debabrata

    2015-11-01

    A simplified approach for analyzing the biofilm process in deriving an easy model has been presented. This simplified biofilm model formulated correlations between substrate concentration in the influent/effluent and at biofilm-liquid interface along with substrate flux and biofilm thickness. The model essentially considered the external mass transport according to Fick's Law, steady state substrate as well as biomass balance for attached growth microorganisms. In substrate utilization, Monod growth kinetics has been followed incorporating relevant boundary conditions at the liquid-biofilm interface and at the attachment surface. The numerical solution of equations was accomplished using Runge-Kutta method and accordingly an integrated computer program was developed. The model has been successfully applied in a distinct set of trials with varying range of representative input variables. The model performance was compared with available existing methods and it was found an easy, accurate method that can be used for process design of biofilm reactor.

  10. Simulation Modeling for Service-Oriented Development

    Directory of Open Access Journals (Sweden)

    Elena Orta

    2008-01-01

    Full Text Available As a consequence of the growing customer orientation of business, organizations are now showing a big interest in the development of technological solutions that allow them both to offer a quick respond to their customers and procuring operational efficiency. In this sense, SOA can be seen as a mechanism to help achieve the alignment of business goals and objectives with technology capability. SOA benefits an organization by abstracting business services from the specific technologies they are developed with. However, to translate SOA benefits into successful software development projects, well defined processes to develop software from business processes are needed. To achieve this, simulation modeling techniques can be useful tools since they make it possible to model and improve both business processes within organizations and their service-oriented development process.This paper presents a set of domains in service-oriented development where simulation modeling can be applied and discusses the benefits of this application.These domains are also related with the different phases of a general SOA lifecycle. An overview of the main works in this field is also included.

  11. 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...

  12. 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.

  13. 77 FR 31351 - Adequacy Determination for Aspen PM10 and Fort Collins Carbon Monoxide Maintenance Plans' Motor...

    Science.gov (United States)

    2012-05-25

    ... 93.118(e)(4), which was promulgated August 15, 1997 (62 FR 43780). We described our process for... (69 FR 40004). In addition, in certain areas with monitored ambient carbon monoxide (CO) values... AGENCY Adequacy Determination for Aspen PM and Fort Collins Carbon Monoxide Maintenance Plans'...

  14. Acute O 3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment.

    Science.gov (United States)

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

    2011-09-01

    We studied the effect of high ozone (O(3)) concentration (110-490 nmol mol(-1)) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O(3) pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O(3) exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O(3) and/or CO(2) for 12 years, were harvested. Acute O(3) damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O(3) damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O(3) damage as it directly controlled O(3) uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O(3) exposure. Moreover, elevated CO(2) did not ameliorate the adverse effects of acute O(3) dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O(3) levels.

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

    Energy Technology Data Exchange (ETDEWEB)

    Darbah, J.N.; Nagy, J.; Jones, W. S.; Burton, A. J.; Kubiske, M. E.

    2011-10-01

    We studied the effect of high ozone (O{sub 3}) concentration (110-490 nmol mol{sup -1}) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O{sub 3} pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O{sub 3} exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O{sub 3} and/or CO{sub 2} for 12 years, were harvested. Acute O{sub 3} damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O{sub 3} damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O{sub 3} damage as it directly controlled O{sub 3} uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O{sub 3} exposure. Moreover, elevated CO{sub 2} did not ameliorate the adverse effects of acute O{sub 3} dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O{sub 3} levels.

  16. Compound leaf development in model plant species.

    Science.gov (United States)

    Bar, Maya; Ori, Naomi

    2015-02-01

    Plant leaves develop in accordance with a common basic program, which is flexibly adjusted to the species, developmental stage and environment. Two key stages of leaf development are morphogenesis and differentiation. In the case of compound leaves, the morphogenesis stage is prolonged as compared to simple leaves, allowing for the initiation of leaflets. Here, we review recent advances in the understanding of how plant hormones and transcriptional regulators modulate compound leaf development, yielding a substantial diversity of leaf forms, focusing on four model compound leaf organisms: cardamine (Cardamine hirsuta), tomato (Solanum lycopersicum), medicago (Medicago truncatula) and pea (Pisum sativum).

  17. Gis in Tourism Development Using Spatial Modelling

    Science.gov (United States)

    Juodkienė, Vytautė

    2014-12-01

    The article deals with a spatial problem - setting the best places for tourism development in Panevėžys district (Lithuania). In order to select areas using ArcGIS software, there was developed a model that evaluated the criteria that influence the selection of areas suitable for tourism. The article presents a digital map, which indicates most suitable locations for rural development by evaluating zones by points in order of importance. The evaluation scale is from 10 points (the most suitable location) to 2 points (the least suitable location). Evaluation points in thematic maps indicate exact locations that are most suitable for tourism homesteads.

  18. Developing a TQM quality management method model

    NARCIS (Netherlands)

    Zhang, Zhihai

    1997-01-01

    From an extensive review of total quality management literature, the external and internal environment affecting an organization's quality performance and the eleven primary elements of TQM are identified. Based on the primary TQM elements, a TQM quality management method model is developed. This mo

  19. Conceptual approach to modeling karst development

    OpenAIRE

    Mihael Brenčič

    1995-01-01

    Karst is probably one of the most complicated hydrogeological systems at all.Its structure is complex and it changes in time. In the article conceptual approaches are described which could help establishing numerical simulation models for karst development. These approaches repose on the systems theory and the concept of the pure karst.

  20. Model for Developing Data Management Policy Language

    OpenAIRE

    Mann, Wendy; Corey, Bill; Wilson, Tom; Hall, Nathan

    2013-01-01

    1 p.; 30" x 18". Representatives from four ASERL and SURA member academic libraries analyzed existing institutional data management policies in order to develop model data management policy language. This poster outlines milestones and a timeline of the ASERL/SURA Data Policy Working Group's process. Association for Southeastern Research Libraries. Southeastern Universities Research Association.

  1. Energy and development : A modelling approach

    NARCIS (Netherlands)

    van Ruijven, B.J.

    2008-01-01

    Rapid economic growth of developing countries like India and China implies that these countries become important actors in the global energy system. Examples of this impact are the present day oil shortages and rapidly increasing emissions of greenhouse gases. Global energy models are used explore p

  2. Developing a Motivational Model of College Achievement.

    Science.gov (United States)

    Tuckman, Bruce W.; Abry, Dennis

    This study involves developing a motivational model of college achievement. The predictor variables, which were procrastination tendency, self-efficacy, self-regulation, intrinsic value, outcome value, cognitive strategy, test anxiety, students grade goals, parent grade goals, and grade point average, as well as the criterion variable exam…

  3. Ongoing Model Development Analyzing Glass Fracture

    DEFF Research Database (Denmark)

    Molnar, G.; Bojtar, I.; Nielsen, Jens Henrik

    2013-01-01

    Present subject deals with an ongoing experimental and numerical analysis of inplane loaded glass plates. The main goal of the investigation is to develop a hybrid – discrete and finite element – model which could follow the fracture process in annealed and in tempered glass. Measurements...

  4. Evolutionary modelling of transitions to sustainable development

    International Nuclear Information System (INIS)

    This thesis has examined how evolutionary economics can contribute to modelling the micromechanisms that underlie transitions towards sustainable development. In general, transitions are fundamental or structural system changes. They involve, or even require, escaping lock-in of dominant, environmentally unsustainable technologies, introducing major technical or social innovations, and changing prevailing social practices and structures. Due to the complexity of socioeconomic interactions, it is not always possible to identify, and thus target with appropriate policy instruments, causes of specific unsustainable patterns of behaviour. Formal modelling exercises can help improve our understanding of the interaction of various transition mechanisms which are otherwise difficult to grasp intuitively. They allow exploring effects of policy interventions in complex systems. However, existing models of transitions focus on social phenomena and seldom address economic problems. As opposed, mainstream (neoclassical) economic models of technological change do not account for social interactions, and changing heterogeneity of users and their perspectives - even though all of these can influence the direction of innovations and patterns of socio-technological development. Evolutionary economics offers an approach that goes beyond neoclassical economics - in the sense of employing more realistic assumptions regarding the behaviour and heterogeneity of consumers, firms and investors. It can complement current transition models by providing them with a better understanding of associated economic dynamics. In this thesis, formal models were proposed to illustrate the usefulness of a range of evolutionary-economic techniques for modelling transitions. Modelling exercises aimed to explain the core properties of socio-economic systems, such as lock-in, path-dependence, coevolution, group selection and recombinant innovation. The studies collected in this dissertation illustrate that

  5. Pulverized Coal Gasification Simulation Based on Aspen Plus Software%基于Aspen Plus的粉煤气化模拟

    Institute of Scientific and Technical Information of China (English)

    张宗飞; 汤连英; 吕庆元; 章卫星; 何正兆; 毕东煌

    2008-01-01

    Aspen Plus为模拟工具,选择反应平衡模型,并应用Gibbs自由能最小化方法建立了Shell粉煤气化模型;通过对神华、沾化和天碱煤种的气化模拟,对建立的模型进行了检验,结果表明:用N2输送粉煤的气化过程能够很好地模拟,而用CO2输送粉煤的气化过程模拟偏差较大.以沾化煤种为例,检验了气化炉散热损失取煤总热值约2%的合理性;研究了不同操作条件下的气化性能,结果表明:提高温度和压力可使气化过程得到强化.

  6. Model Driven Software Development for Agricultural Robotics

    DEFF Research Database (Denmark)

    Larsen, Morten

    2016-01-01

    The design and development of agricultural robots, consists of both mechan- ical, electrical and software components. All these components must be de- signed and combined such that the overall goal of the robot is fulfilled. The design and development of these systems require collaboration between...... processing, control engineering, etc. This thesis proposes a Model-Driven Software Develop- ment based approach to model, analyse and partially generate the software implementation of a agricultural robot. Furthermore, Guidelines for mod- elling the architecture of an agricultural robots are provided......, assisting with bridging the different engineering disciplines. Timing play an important role in agricultural robotic applications, synchronisation of robot movement and implement actions is important in order to achieve precision spraying, me- chanical weeding, individual feeding, etc. Discovering...

  7. Inducer analysis/pump model development

    Science.gov (United States)

    Cheng, Gary C.

    1994-01-01

    Current design of high performance turbopumps for rocket engines requires effective and robust analytical tools to provide design information in a productive manner. The main goal of this study was to develop a robust and effective computational fluid dynamics (CFD) pump model for general turbopump design and analysis applications. A finite difference Navier-Stokes flow solver, FDNS, which includes an extended k-epsilon turbulence model and appropriate moving zonal interface boundary conditions, was developed to analyze turbulent flows in turbomachinery devices. In the present study, three key components of the turbopump, the inducer, impeller, and diffuser, were investigated by the proposed pump model, and the numerical results were benchmarked by the experimental data provided by Rocketdyne. For the numerical calculation of inducer flows with tip clearance, the turbulence model and grid spacing are very important. Meanwhile, the development of the cross-stream secondary flow, generated by curved blade passage and the flow through tip leakage, has a strong effect on the inducer flow. Hence, the prediction of the inducer performance critically depends on whether the numerical scheme of the pump model can simulate the secondary flow pattern accurately or not. The impeller and diffuser, however, are dominated by pressure-driven flows such that the effects of turbulence model and grid spacing (except near leading and trailing edges of blades) are less sensitive. The present CFD pump model has been proved to be an efficient and robust analytical tool for pump design due to its very compact numerical structure (requiring small memory), fast turnaround computing time, and versatility for different geometries.

  8. Developing Project Duration Models in Software Engineering

    Institute of Scientific and Technical Information of China (English)

    Pierre Bourque; Serge Oligny; Alain Abran; Bertrand Fournier

    2007-01-01

    Based on the empirical analysis of data contained in the International Software Benchmarking Standards Group(ISBSG) repository, this paper presents software engineering project duration models based on project effort. Duration models are built for the entire dataset and for subsets of projects developed for personal computer, mid-range and mainframeplatforms. Duration models are also constructed for projects requiring fewer than 400 person-hours of effort and for projectsre quiring more than 400 person-hours of effort. The usefulness of adding the maximum number of assigned resources as asecond independent variable to explain duration is also analyzed. The opportunity to build duration models directly fromproject functional size in function points is investigated as well.

  9. Advanced Small Modular Reactor Economics Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Thomas J [ORNL

    2014-10-01

    The US Department of Energy Office of Nuclear Energy’s Advanced Small Modular Reactor (SMR) research and development activities focus on four key areas: Developing assessment methods for evaluating advanced SMR technologies and characteristics; and Developing and testing of materials, fuels and fabrication techniques; and Resolving key regulatory issues identified by US Nuclear Regulatory Commission and industry; and Developing advanced instrumentation and controls and human-machine interfaces. This report focuses on development of assessment methods to evaluate advanced SMR technologies and characteristics. Specifically, this report describes the expansion and application of the economic modeling effort at Oak Ridge National Laboratory. Analysis of the current modeling methods shows that one of the primary concerns for the modeling effort is the handling of uncertainty in cost estimates. Monte Carlo–based methods are commonly used to handle uncertainty, especially when implemented by a stand-alone script within a program such as Python or MATLAB. However, a script-based model requires each potential user to have access to a compiler and an executable capable of handling the script. Making the model accessible to multiple independent analysts is best accomplished by implementing the model in a common computing tool such as Microsoft Excel. Excel is readily available and accessible to most system analysts, but it is not designed for straightforward implementation of a Monte Carlo–based method. Using a Monte Carlo algorithm requires in-spreadsheet scripting and statistical analyses or the use of add-ons such as Crystal Ball. An alternative method uses propagation of error calculations in the existing Excel-based system to estimate system cost uncertainty. This method has the advantage of using Microsoft Excel as is, but it requires the use of simplifying assumptions. These assumptions do not necessarily bring into question the analytical results. In fact, the

  10. DEVELOPMENT OF TECHNOLOGIES AND ANALYTICAL CAPABILITIES FOR VISION 21 ENERGY PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Madhava Syamlal, Ph.D.

    2002-07-01

    A software design review meeting was held May 2-3 in Lebanon, NH. The work on integrating a reformer model based on CFD with a fuel cell flow sheet was completed (Task 2.0). The CFD database design was completed and the database API's finalized. A file -based CFD database was implemented and tested (Task 2.8). The task COM-CORBA Bridge-I was completed. The bridge now has CO interfaces for transferring reaction kinetics information from Aspen Plus to Fluent (Task 2.11). The capability for transferring temperature-dependent physical properties from Aspen Plus to Fluent was implemented (Task 2.12). Work on ''Model Selection'' GUI was completed. This GUI allows the process analyst to select models from the CFD database. Work on ''Model Edit'' GUI was started (Task 2.13). A version of Aspen Plus with the capability for using CO parameters in ''design spec'' analysis has become available. With this version being available, work on adding CO wrapper to INDVU code has been started (Task 2.15). A preliminary design for the Solution Strategy class was developed (Task 2.16). The requirements for transferring pressure data between Aspen Plus and Fluent were defined. The ability to include two CFD models in a flow sheet was successfully tested. The capability to handle multiple inlets and outlets in a CO block was tested (Task 2.17). A preliminary version of the Configuration Wizard, which helps a user to make any Fluent model readable from a process simulator, was developed and tested (Task 2.18). Work on constructing a flow sheet model for Demo Case 2 was started. The work on documenting Demo Case 2 is nearing completion (Task 3.2). A Fluent heat exchanger model was installed and tested. Work on calibrating the heat exchanger model was started (Task 4.1). An advisory board meeting was held in conjunction with the Fluent Users Group Meeting on Monday, June 10, 2002. The meeting minutes and presentations for the

  11. Model developed for economic gas dispatch

    International Nuclear Information System (INIS)

    Essex County Gas Co. is using at new, highly efficient approach to simulate the daily economic dispatch of gas supplies to meet market requirements under FERC Order 636. Although sophisticated in its design, the modeling environment permits straightforward model construction with richly detailed components that can be readily changed as needed by gas utility personnel after only a short training period. It provides a mechanism for very detailed simulation of the market and supply balances governing LDC operations. The model serves as Essex County Gas' primary what if? tool for testing the operational and economic consequences of a wide variety of supply and demand-side-management alternatives. The model, developed by consultant E.J. Curtis, is driven by Effective Heating Degree-Day daily weather patterns, such as design, normal, warm and extreme. The model is driven by weather patterns input as time series, so other independent variables such as general inflation factors, energy cost projections and economic model results can also be input as time-series data. Alternatively, detailed submodels for such components can be imbedded within the model to automatically generate this information. It incorporates supply and market simulation elements, permitting ready adaptation for use not only in conventional supply planning but also integrated resource management. Comparative 'what if?' cases can be run with specific demand-side management initiatives toggled on and off

  12. Heat Pump Clothes Dryer Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL

    2016-01-01

    A heat pump clothes dryer (HPCD) is an innovative appliance that uses a vapor compression system to dry clothes. Air circulates in a closed loop through the drum, so no vent is required. The condenser heats air to evaporate moisture out of the clothes, and the evaporator condenses water out of the air stream. As a result, the HPCD can achieve 50% energy savings compared to a conventional electric resistance dryer. We developed a physics-based, quasi-steady-state HPCD system model with detailed heat exchanger and compressor models. In a novel approach, we applied a heat and mass transfer effectiveness model to simulate the drying process of the clothes load in the drum. The system model is able to simulate the inherently transient HPCD drying process, to size components, and to reveal trends in key variables (e.g. compressor discharge temperature, power consumption, required drying time, etc.) The system model was calibrated using experimental data on a prototype HPCD. In the paper, the modeling method is introduced, and the model predictions are compared with experimental data measured on a prototype HPCD.

  13. Dynamics models and modeling of tree stand development

    Directory of Open Access Journals (Sweden)

    M. V. Rogozin

    2015-04-01

    Full Text Available Brief analysis of scientific works in Russia and in the CIS over the past 100 years. Logical and mathematical models consider the conceptual and show some of the results of their verification. It was found that the models include different laws and the parameters, the sum of which allows you to divide them into four categories: models of static states, development models, models of care for the natural forest and models of cultivation. Each category has fulfilled and fulfills its tasks in economic management. Thus, the model states in statics (table traverse growth played a prominent role in figuring out what may be the most productive (full stands in different regions of the country. However, they do not answer the question of what the initial states lead to the production of complete stands. In a study of the growth of stands used system analysis, and it is observed dominance of works studying static state, snatched from the biological time. Therefore, the real drama of the growth of stands remained almost unexplored. It is no accident there were «chrono-forestry» «plantation forestry» and even «non-traditional forestry», where there is a strong case of a number of new concepts of development stands. That is quite in keeping with Kuhn (Kuhn, 2009 in the forestry crisis began – there were alternative theories and coexist conflicting scientific schools. To develop models of stand development, it is proposed to use a well-known method of repeated observations within 10–20 years, in conjunction with the explanation of the history of the initial density. It mounted on the basis of studying the dynamics of its indicators: the trunk, crown overlap coefficient, the sum of volumes of all crowns and the relative length of the crown. According to these indicators, the researcher selects natural series of development stands with the same initial density. As a theoretical basis for the models it is possible to postulate the general properties of

  14. Preliminary Phase Field Computational Model Development

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yulan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hu, Shenyang Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Ke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Suter, Jonathan D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCloy, John S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Bradley R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-15

    This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in

  15. Recent developments in modeling groundwater systems

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, T.N.; Witherspoon, P.A.

    1977-05-20

    This paper reviews the developments in the mathematical modeling of groundwater systems over the past decde. The first part of the paper is devoted to a description of the physics of the different types of problems that are of interest in hydrogeology and a statement of the related initial-boundary-value problems. The various numerical techniques that have been employed to solve the governing equations are discussed in the second part. In the third section a few typical case histories are presented to illustrate the trend of progress that has occurred in the application of mathematical modeling to actual field problems.

  16. Fuzzy logic marketing models for sustainable development

    Directory of Open Access Journals (Sweden)

    Ioan Constantin ENACHE

    2015-06-01

    Full Text Available Fuzzy logic offers a different approach to describe economic and marketing phenomena. By providing a replacement for crisp values the fuzzy sets proved to be efficient alternatives for customer behaviour analysis. These advantages can provide a new way to address sustainable development issues. The present paper aims at presenting the main characteristics of fuzzy models and their main advantages. Evidence on how to implement a fuzzy model and what are its strong points are provided based on previous research and published scientific papers. It is concluded that fuzzy logic gives a different view on a wide range of topics

  17. Application software development via model based design

    OpenAIRE

    Haapala, O. (Olli)

    2015-01-01

    This thesis was set to study the utilization of the MathWorks’ Simulink® program in model based application software development and its compatibility with the Vacon 100 inverter. The target was to identify all the problems related to everyday usage of this method and create a white paper of how to execute a model based design to create a Vacon 100 compatible system software. Before this thesis was started, there was very little knowledge of the compatibility of this method. However durin...

  18. Alternative Local Development models from the periphery

    Directory of Open Access Journals (Sweden)

    Mauricio Lopez Oropeza

    2013-09-01

    Full Text Available As neoliberal capitalism continues to fail on reducing inequities, and continues to fail on fulfilling its promise of a kind of “development” that would allow impoverished men and women to improve their situation and be able to experience a “freedom” which would empower them with new and better opportunities to vanish their many types of “poverties”, new and alternative models raise, presenting a different and inclusive type of development which intends to respond to their particular situations of exclusion and build on an alternative model.

  19. 美国 ACUSON ASPEN SN31893彩超特殊故障 1例

    Institute of Scientific and Technical Information of China (English)

    张涛

    2001-01-01

    @@美国 ASPEN SN31893彩超系美国 ACUSON公司的最新一代产品,为新一代全功能彩超,该机型在部队医院拥有量较大,据对经销商了解还没有出现过类似的故障。 故障现象 开机后机器开始自检, 4MB DRAM OK。然后是 ACUSON ASPEN的杉树图象出现,机器进入 POWER DIAGNOSTICS,一段时间后出现错误提示:

  20. The Aspen Framework for Dark Matter Substructure Inference from Strong Gravitational Lensing Observations

    Science.gov (United States)

    Moustakas, Leonidas A.; Cyr-Racine, Francis-Yan; Keeton, Charles R.

    2016-01-01

    The properties of the dark matter particle or particles lead to different small scale halo populations, distributions, and evolution over cosmic time. We introduce a new method for characterizing the properties of substructure within galaxies through the power spectrum of potential fluctuations, and demonstrate how complete sets of multiwavelength imaging and time domain observations can be processed directly to infer all facets of the strong gravitational lensing components and source properties, including the dark matter substructure power spectrum constraints. We are able to take advantage of analysis parallels with cosmic background radiation techniques, and furthermore demonstrate how this technique, dubbed The Aspen Framework, reduces to the long-standing approach of working with reduced or derived observable quantities in lensing.

  1. Carbohydrate reactions during high-temperature steam treatment of aspen wood.

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2005-06-01

    Aspen wood was treated with steam at different time-temperature severity factors. Analysis of the amounts of acids released revealed a relationship between the acidity and the formation of furfural and hydroxymethyl furfural as degradation products from carbohydrates. It is suggested that two concurrent or consecutive mechanisms are responsible for the observed results: a homolytic cleavage and an acid hydrolysis of glucosidic linkages in the polysaccharides. By preimpregnating the wood with alkali, hydrolysis can be eliminated, resulting in a much cleaner depolymerization of the polysaccharides without any further acid-catalyzed degradation. The enzymatic digestibility of the steam-treated wood material for the formation of glucose was compared with that of steam-exploded wood. A more efficient route for glucose production from steam-exploded wood was found as long as the biomass-pretreated material was homogeneous and without shives.

  2. Animal models in drug development for MRSA.

    Science.gov (United States)

    Marra, Andrea

    2014-01-01

    One of the foremost challenges of drug discovery in any therapeutic area is that of solidifying the correlation between in vitro activity and clinical efficacy. Between these is the confirmation that affecting a particular target in vivo will lead to a therapeutic benefit. In antibacterial drug discovery, there is a key advantage from the start, since the targets are bacteria-therefore, it is simple to ascertain in vitro whether a drug has the desired effect, i.e., bacterial cell inhibition or killing, and to understand the mechanism by which that occurs. The downstream criteria, whether a compound reaches the infection site and achieves appropriately high levels to affect bacterial viability, can be evaluated in animal models of infection. In this way animal models of infection can be a highly valuable and predictive bridge between in vitro drug discovery and early clinical evaluation.The Gram-positive pathogen Staphylococcus aureus causes a wide variety of infections in humans (Archer, Clin Infect Dis 26:1179-1181, 1998) and has been said to be able to infect every tissue type. Fortunately, over the years a great deal of effort has been expended toward developing infection models in rodents using this organism, with good success. This chapter will describe the advantages, methods, and outcome measurements of the rodent models most used in drug discovery for S. aureus. Mouse models will be the focus of this chapter, as they are the most economical and thus most commonly used, but a rat infection model is included as well.

  3. Cytoview: Development of a cell modelling framework

    Indian Academy of Sciences (India)

    Prashant Khodade; Samta Malhotra; Nirmal Kumar; M Sriram Iyengar; N Balakrishnan; Nagasuma Chandra

    2007-08-01

    The biological cell, a natural self-contained unit of prime biological importance, is an enormously complex machine that can be understood at many levels. A higher-level perspective of the entire cell requires integration of various features into coherent, biologically meaningful descriptions. There are some efforts to model cells based on their genome, proteome or metabolome descriptions. However, there are no established methods as yet to describe cell morphologies, capture similarities and differences between different cells or between healthy and disease states. Here we report a framework to model various aspects of a cell and integrate knowledge encoded at different levels of abstraction, with cell morphologies at one end to atomic structures at the other. The different issues that have been addressed are ontologies, feature description and model building. The framework describes dotted representations and tree data structures to integrate diverse pieces of data and parametric models enabling size, shape and location descriptions. The framework serves as a first step in integrating different levels of data available for a biological cell and has the potential to lead to development of computational models in our pursuit to model cell structure and function, from which several applications can flow out.

  4. Ecological aspects in sustainable development model

    International Nuclear Information System (INIS)

    Environment problems are caused by intensive use of natural resources due to scientific progress in combination with the present structure of unlimited consumption. To prevent the impending ecological disaster a model of sustainable development has been worked out. It is aimed at satisfying the ever-growing requirements of the modern man without damaging the environment. Scientifically grounded use of nature mat contribute to solution of the problem. The acceptable use of nature should take account of the land ecosystem resources which is ensured by reliable model including flow balance in particular. Irreversible flows generate entropy which could be the universal measure of technic genetics impact. Entropic condition of the acceptable (sustainable) development are started: techno-genic entropy production must be less than natural entropy production. Particular sciences should be re-oriented towards environmental problems. Environmental monitoring strategy should provide for determination of macro properties as well as flows. (author)

  5. Development of an energy storage tank model

    Science.gov (United States)

    Buckley, Robert Christopher

    A linearized, one-dimensional finite difference model employing an implicit finite difference method for energy storage tanks is developed, programmed with MATLAB, and demonstrated for different applications. A set of nodal energy equations is developed by considering the energy interactions on a small control volume. The general method of solving these equations is described as are other features of the simulation program. Two modeling applications are presented: the first using a hot water storage tank with a solar collector and an absorption chiller to cool a building in the summer, the second using a molten salt storage system with a solar collector and steam power plant to generate electricity. Recommendations for further study as well as all of the source code generated in the project are also provided.

  6. Model of Development Planning of Tourist Enterprise

    OpenAIRE

    Ivanyuk Ulyana V.

    2013-01-01

    The paper proposes a model of planning and development of tourist business. The model allows: 1) to justify the process of distribution of company profits, and 2) to select the optimal mode of its operation and the best operating conditions, and 3) make the selection of parameters for which the tour company created favorable conditions for the development and 4) to determine the optimal tax rate in favor of the company.В статье предложена модель планирования развития туристического предприяти...

  7. Model of the Product Development Lifecycle.

    Energy Technology Data Exchange (ETDEWEB)

    He, Sunny L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roe, Natalie H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wood, Evan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nachtigal, Noel M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Helms, Jovana [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    While the increased use of Commercial Off-The-Shelf information technology equipment has presented opportunities for improved cost effectiveness and flexibility, the corresponding loss of control over the product's development creates unique vulnerabilities and security concerns. Of particular interest is the possibility of a supply chain attack. A comprehensive model for the lifecycle of hardware and software products is proposed based on a survey of existing literature from academic, government, and industry sources. Seven major lifecycle stages are identified and defined: (1) Requirements, (2) Design, (3) Manufacturing for hardware and Development for software, (4) Testing, (5) Distribution, (6) Use and Maintenance, and (7) Disposal. The model is then applied to examine the risk of attacks at various stages of the lifecycle.

  8. Animal Migraine Models for Drug Development

    DEFF Research Database (Denmark)

    Jansen-Olesen, Inger; Tfelt-Hansen, Peer; Olesen, Jes

    2013-01-01

    Migraine is number seven in WHO's list of all diseases causing disability and the third most costly neurological disorder in Europe. Acute attacks are treatable by highly selective drugs such as the triptans but there is still a huge unmet therapeutic need. Unfortunately, drug development...... for headache has almost come to a standstill partly because of a lack of valid animal models. Here we review previous models with emphasis on optimal characteristics of a future model. In addition to selection of animal species, the method of induction of migraine-like changes and the method of recording...... responses elicited by such measures are crucial. The most naturalistic way of inducing attacks is by infusion of endogenous signaling molecules that are known to cause migraine in patients. The most valid response is recording of neural activity in the trigeminal system. The most useful headache related...

  9. SOFTWARE DEVELOPMENT MODEL FOR ETHNOBILINGUAL DICTIONARIES

    Directory of Open Access Journals (Sweden)

    Melchora Morales-Sánchez

    2010-09-01

    Full Text Available A software development integral model for a dictionary to store and retrieve textual, visual, and most important, incorporating the audio of oral language. Taking into account both the characterization of indigenous cultural reality and the technical aspects of software construction. Such model consists of the next phases: context description, lexicographic design, computer design and multimedia, construction and tests of the application. There isn´t doubt about the influence of the contact of Spanish language with the variety of languages spoken throughout Latin-America causing the most diverse and extensive communications. Causing that in the interior of communities are interested in preserving their language tongue for people to identify themselves with their own roots and transmit this legacy to the next generations. The model its design to develop dictionary software with factors that are certain in indigenous reality as they are: low budget, functioning in computers with limited resources and human resources with minimum capabilities. And is exemplified with the development of a Spanish-chatino dictionary spoken in the town of Santos Reyes Nopala, Oaxaca in the coast region of Mexico.

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

    Institute of Scientific and Technical Information of China (English)

    Zhang Gang; Jaana Luoranen; Heikki Smolander

    2007-01-01

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

  11. Model development for household waste prevention behaviour

    International Nuclear Information System (INIS)

    Highlights: ► We model waste prevention behaviour using structure equation modelling. ► We merge attitude–behaviour theories with wider models from environmental psychology. ► Personal norms and perceived behaviour control are the main behaviour predictors. ► Environmental concern, moral obligation and inconvenience are the main influence on the behaviour. ► Waste prevention and recycling are different dimensions of waste management behaviour. - Abstract: Understanding waste prevention behaviour (WPB) could enable local governments and decision makers to design more-effective policies for reducing the amount of waste that is generated. By merging well-known attitude–behaviour theories with elements from wider models from environmental psychology, an extensive cognitive framework that provides new and valuable insights is developed for understanding the involvement of individuals in waste prevention. The results confirm the usefulness of the theory of planned behaviour and of Schwartz’s altruistic behaviour model as bases for modelling participation in waste prevention. A more elaborate integrated model of prevention was shown to be necessary for the complete analysis of attitudinal aspects associated with waste prevention. A postal survey of 158 respondents provided empirical support for eight of 12 hypotheses. The proposed structural equation indicates that personal norms and perceived behaviour control are the main predictors and that, unlike the case of recycling, subjective norms have a weak influence on WPB. It also suggests that, since social norms have not presented a direct influence, WPB is likely to be influenced by a concern for the environment and the community as well by perceptions of moral obligation and inconvenience. Results also proved that recycling and waste prevention represent different dimensions of waste management behaviour requiring particular approaches to increase individuals’ engagement in future policies.

  12. Dynamic Modeling of Process Technologies for Closed-Loop Water Recovery Systems

    Science.gov (United States)

    Allada, Rama Kumar; Lange, Kevin E.; Anderson, Molly S.

    2012-01-01

    Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents dynamic simulations of chemical process for primary processor technologies including: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system, the Wiped-Film Rotating Disk (WFRD), and post-distillation water polishing processes such as the Volatiles Removal Assembly (VRA). These dynamic models were developed using the Aspen Custom Modeler (Registered TradeMark) and Aspen Plus(Registered TradeMark) process simulation tools. The results expand upon previous work for water recovery technology models and emphasize dynamic process modeling and results. The paper discusses system design, modeling details, and model results for each technology and presents some comparisons between the model results and available test data. Following these initial comparisons, some general conclusions and forward work are discussed.

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

    Science.gov (United States)

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

    2014-06-01

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

  14. Simulation models and designs for advanced Fischer-Tropsch technology

    Energy Technology Data Exchange (ETDEWEB)

    Choi, G.N.; Kramer, S.J.; Tam, S.S. [Bechtel Corp., San Francisco, CA (United States)

    1995-12-31

    Process designs and economics were developed for three grass-roots indirect Fischer-Tropsch coal liquefaction facilities. A baseline and an alternate upgrading design were developed for a mine-mouth plant located in southern Illinois using Illinois No. 6 coal, and one for a mine-mouth plane located in Wyoming using Power River Basin coal. The alternate design used close-coupled ZSM-5 reactors to upgrade the vapor stream leaving the Fischer-Tropsch reactor. ASPEN process simulation models were developed for all three designs. These results have been reported previously. In this study, the ASPEN process simulation model was enhanced to improve the vapor/liquid equilibrium calculations for the products leaving the slurry bed Fischer-Tropsch reactors. This significantly improved the predictions for the alternate ZSM-5 upgrading design. Another model was developed for the Wyoming coal case using ZSM-5 upgrading of the Fischer-Tropsch reactor vapors. To date, this is the best indirect coal liquefaction case. Sensitivity studies showed that additional cost reductions are possible.

  15. Developing a Common Information Model for climate models and data

    Science.gov (United States)

    Valcke, S.; Balaji, V.; Bentley, P.; Guilyardi, E.; Lawrence, B.; Pascoe, C.; Steenman-Clark, L.; Toussaint, F.; Treshansky, A.

    2009-04-01

    The Metafor project, funded under the EU Framework Programme 7, proposes a Common Information Model (CIM) to describe in a standard way climate data and the models and modelling environments that produced this data. To establish the CIM, Metafor first considered the metadata models developed by other groups engaged in similar efforts in Europe and worlwide, such as the US Earth System Curator, explored fragmentation and gaps as well as duplication of information present in these metadata models, and reviewed current problems in identifying, accessing or using climate data present in existing repositories. Based on this analysis and on different use cases, the first version of the CIM is composed of 5 packages. The "data" package is used to describe the data objects that can be collected and stored in any number of ways; the "activity" package details the simulations and experiments and related requirements that were performed with numerical (possibly coupled) models described with the "software" packages. Both data and models can be associated with numerical grids represented by the "grid" package and finally the "shared" package gathers concepts shared among the other packages. The CIM is defined and implemented in the Unified Modelling Language (UML) and application schema have been generated in XML schema. Aiming at a wide adoption of the CIM, Metafor will optimize the way climate data infrastructures are used to store knowledge, thereby adding value to primary research data and information, and providing an essential asset for the numerous stakeholders actively engaged in climate change issues (policy, research, impacts, mitigation, private sector).

  16. Development of New Co-gasification Technology Based on Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yue-hong; WEN Hao; GUO Zhan-cheng; XU Zhi-hong

    2005-01-01

    A new co-gasification technology was proposed. The core of this co-gasification technology is a gasifier capable of being operated on a wide range of fuels and being reconstructed from blast furnace or shaft furnace.Based on this innovative concept, the lab-scale experiment and modeling study were carried out to demonstrate its technical validity and thermodynamic characteristics. The obtained results indicate that co-gasification process can be undertaken under ideal thermodynamic conditions where quasi-equilibrium could be reached without catalysts and Aspen Plus is a useful tool for this process development. Furthermore, potential applications of co-gasification were discussed.

  17. Development of a smart DC grid model

    Science.gov (United States)

    Dalimunthe, Amty Ma'rufah Ardhiyah; Mindara, Jajat Yuda; Panatarani, Camellia; Joni, I. Made

    2016-03-01

    Smart grid and distributed generation should be the solution of the global climate change and the crisis energy of the main source of electrical power generation which is fossil fuel. In order to meet the rising electrical power demand and increasing service quality demands, as well as reduce pollution, the existing power grid infrastructure should be developed into a smart grid and distributed power generation which provide a great opportunity to address issues related to energy efficiency, energy security, power quality and aging infrastructure systems. The conventional of the existing distributed generation system is an AC grid while for a renewable resources requires a DC grid system. This paper explores the model of smart DC grid by introducing a model of smart DC grid with the stable power generation give a minimal and compressed circuitry that can be implemented very cost-effectively with simple components. The PC based application software for controlling was developed to show the condition of the grid and to control the grid become `smart'. The model is then subjected to a severe system perturbation, such as incremental change in loads to test the performance of the system again stability. It is concluded that the system able to detect and controlled the voltage stability which indicating the ability of power system to maintain steady voltage within permissible rangers in normal condition.

  18. QGSM development for spallation reactions modeling

    Directory of Open Access Journals (Sweden)

    Gudima K.K.

    2012-12-01

    Full Text Available The growing interest in spallation neutron sources, accelerator-driven systems, R&D of rare isotope beams, and development of external beam radiation therapy necessitated the improvement of nuclear reaction models for both stand-alone codes for the analysis of nuclear reactions and event generators within the Monte Carlo transport systems for calculations of interactions of high-energy particles with matter in a wide range of energy and in arbitrary 3D geometry of multicomponent targets. The exclusive approach to the description of nuclear reactions is the most effective for detailed calculation of inelastic interactions with atomic nuclei. It provides the correct description of particle production, single- and double-differential spectra, recoil, and fission product yields. This approach has been realized in the Quark Gluon String Model (QGSM for nuclear reactions induced by photons, hadrons, and high energy heavy ions. In this article, improved versions of the QGSM model and a corresponding code have been developed tested and bench marked against experimental data for neutron production in spallation reactions on thin and thick targets in the energy range from a few MeV to several GeV/nucleon.

  19. Nematode model systems in evolution and development.

    Science.gov (United States)

    Sommer, Ralf J; Bumbarger, Daniel J

    2012-01-01

    The free-living nematode Caenorhabditis elegans is one of the most important model organisms in all areas of modern biology. Using the knowledge about C. elegans as a baseline, nematodes are now intensively studied in evolution and development. Evolutionary developmental biology or for short, 'evo-devo' has been developed as a new research discipline during the last two decades to investigate how changes in developmental processes and mechanisms result in the modification of morphological structures and phenotypic novelty. In this article, we review the concepts that make nematode evo-devo a successful approach to evolutionary biology. We introduce selected model systems for nematode evo-devo and provide a detailed discussion of four selected case studies. The most striking finding of nematode evo-devo is the magnitude of developmental variation in the context of a conserved body plan. Detailed investigation of early embryogenesis, gonad formation, vulva development, and sex determination revealed that molecular mechanisms evolve rapidly, often in the context of a conserved body plan. These studies highlight the importance of developmental systems drift and neutrality in evolution. PMID:23801489

  20. A stochastic model for early placental development.

    KAUST Repository

    Cotter, Simon L

    2014-08-01

    In the human, placental structure is closely related to placental function and consequent pregnancy outcome. Studies have noted abnormal placental shape in small-for-gestational-age infants which extends to increased lifetime risk of cardiovascular disease. The origins and determinants of placental shape are incompletely understood and are difficult to study in vivo. In this paper, we model the early development of the human placenta, based on the hypothesis that this is driven by a chemoattractant effect emanating from proximal spiral arteries in the decidua. We derive and explore a two-dimensional stochastic model, and investigate the effects of loss of spiral arteries in regions near to the cord insertion on the shape of the placenta. This model demonstrates that disruption of spiral arteries can exert profound effects on placental shape, particularly if this is close to the cord insertion. Thus, placental shape reflects the underlying maternal vascular bed. Abnormal placental shape may reflect an abnormal uterine environment, predisposing to pregnancy complications. Through statistical analysis of model placentas, we are able to characterize the probability that a given placenta grew in a disrupted environment, and even able to distinguish between different disruptions.

  1. Continuous Extraction and Separation Based on Aspen for the Water of the ISO-Propylene Alcohol-Water%基于Aspen plus异丙醚-异丙醇-水的连续萃取分离

    Institute of Scientific and Technical Information of China (English)

    战俊磊

    2015-01-01

    选用乙二醇(EG)为萃取剂,用Aspen Plus化工模拟软件中的Radfrac单元操作模块,采用UNIFAC物性计算方法,通过优化各参数,在适宜操作条件下,塔顶可以得到高纯度的二异丙醚、异丙醇产品.

  2. Development model of the fine dining restaurant

    OpenAIRE

    Miško Radjenović

    2014-01-01

    Purpose –The purpose of this work is to support the hypothesis that the Fine dining restaurants are important part of hotel offer. Design –In the first and second part of this work the special focus is given on the history and positive and negative aspects offline dining restaurant business. In the third and fourth part, this paper will present the model for fine dining development by analyzing practical examples and steps needed to be taken for opening this type of restaurant. Methodology –H...

  3. MEDSLIK oil spill model recent developments

    Science.gov (United States)

    Lardner, Robin; Zodiatis, George

    2016-04-01

    MEDSLIK oil spill model recent developments Robin Lardner and George Zodiatis Oceanography Center, University of Cyprus, 1678 Nicosia, Cyprus MEDSLIK is a well established 3D oil spill model that predicts the transport, fate and weathering of oil spills and is used by several response agencies and institutions around the Mediterranean, the Black seas and worldwide. MEDSLIK has been used operationally for real oil spill accidents and for preparedness in contingency planning within the framework of pilot projects with REMPEC-Regional Marine Pollution Emergency Response Centre for the Mediterranean Sea and EMSA-European Maritime Safety Agency. MEDSLIK has been implemented in many EU funded projects regarding oil spill predictions using the operational ocean forecasts, as for example the ECOOP, NEREIDs, RAOP-Med, EMODNET MedSea Check Point. Within the frame of MEDESS4MS project, MEDSLIK is at the heart of the MEDESS4MS multi model oil spill prediction system. The MEDSLIK oil spill model contains among other, the following features: a built-in database with 240 different oil types characteristics, assimilation of oil slick observations from in-situ or aerial, to correct the predictions, virtual deployment of oil booms and/or oil skimmers/dispersants, continuous or instantaneous oil spills from moving or drifting ships whose slicks merge can be modelled together, multiple oil spill predictions from different locations, backward simulations for tracking the source of oil spill pollution, integration with AIS data upon the availability of AIS data, sub-surface oil spills at any given water depth, coupling with SAR satellite data. The MEDSLIK can be used for operational intervention for any user-selected region in the world if the appropriate coastline, bathymetry and meteo-ocean forecast files are provided. MEDSLIK oil spill model has been extensively validated in the Mediterranean Sea, both in real oil spill incidents (i.e. during the Lebanese oil pollution crisis in

  4. Implications of Elevated Atmospheric Carbon Dioxide and Tropospheric Ozone for Water Use in Stands of Trembling Aspen and Paper Birch

    Science.gov (United States)

    Rhea, Lee Kirk

    Projected increases in the atmospheric concentration of CO2 and tropospheric O3 over the next 50 years are of concern due in part to their potential to affect forest water budgets. I conducted a series of studies at the Aspen Free Air CO2 and O3 Enrichment experiment near Rhinelander, WI to determine the effect of projected concentrations of these gases for the year 2050 on the water budget in stands of trembling aspen and paper birch. In order to determine the effects of elevated CO2 (eCO 2) and O3 (eO3) on rainfall partitioning between interception, through fall, and stem flow I performed a computerized analysis of photographed canopy branches and compared the results to hydrologic measurements. Elevated O3 significantly decreased total aspen and birch branch length, resulting in net decreases for 2002 whorls of -18 % and 2006 whorls of -16 %. Some of these changes had measurable effects on rainfall partitioning. The biomass of fine roots has been observed to change in response to eCO2 and eO3 at shallow depths, but little work has been done to assess deeper roots. I characterized fine root responses to eCO 2 and eO3 to a depth of one meter. Fumigation with O 3 increased small root biomass in shallow soil 30 % in all aspen plots and decreased root biomass in shallow soil 46 % in aspen-birch plots. Increases in root length up to 131 % and specific root length up to 77 % occurred under eO3 in middle and deep soil layers, indicating more extensive soil exploration at depth. Small root biomass in shallow soils increased 20 % to 24 % under eCO2, indicative of more intensive soil exploration near the surface. Previous studies of sapwood from Aspen-FACE indicated that anatomical structures related to hydraulic conductance (K) differed between aspen clones and that they responded to the treatments differently. I constructed embolism curves for stem wood samples collected below the base of the live crowns. There were no significant treatment effects on K at full water

  5. Argonne Bubble Experiment Thermal Model Development II

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-01

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development”.1 The experiment was performed at Argonne National Laboratory (ANL) in 2014.2 A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at three beam power levels, 6, 12 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was observed. This report will describe the Computational Fluid Dynamics (CFD) model that was developed to calculate the temperatures and gas volume fractions in the solution vessel during the irradiations. The previous report1 described an initial analysis performed on a geometry that had not been updated to reflect the as-built solution vessel. Here, the as-built geometry is used. Monte-Carlo N-Particle (MCNP) calculations were performed on the updated geometry, and these results were used to define the power deposition profile for the CFD analyses, which were performed using Fluent, Ver. 16.2. CFD analyses were performed for the 12 and 15 kW irradiations, and further improvements to the model were incorporated, including the consideration of power deposition in nearby vessel components, gas mixture composition, and bubble size distribution. The temperature results of the CFD calculations are compared to experimental measurements.

  6. Argonne Bubble Experiment Thermal Model Development II

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-01

    This report describes the continuation of the work reported in “Argonne Bubble Experiment Thermal Model Development”. The experiment was performed at Argonne National Laboratory (ANL) in 2014. A rastered 35 MeV electron beam deposited power in a solution of uranyl sulfate, generating heat and radiolytic gas bubbles. Irradiations were performed at three beam power levels, 6, 12 and 15 kW. Solution temperatures were measured by thermocouples, and gas bubble behavior was observed. This report will describe the Computational Fluid Dynamics (CFD) model that was developed to calculate the temperatures and gas volume fractions in the solution vessel during the irradiations. The previous report described an initial analysis performed on a geometry that had not been updated to reflect the as-built solution vessel. Here, the as-built geometry is used. Monte-Carlo N-Particle (MCNP) calculations were performed on the updated geometry, and these results were used to define the power deposition profile for the CFD analyses, which were performed using Fluent, Ver. 16.2. CFD analyses were performed for the 12 and 15 kW irradiations, and further improvements to the model were incorporated, including the consideration of power deposition in nearby vessel components, gas mixture composition, and bubble size distribution. The temperature results of the CFD calculations are compared to experimental measurements.

  7. Characterization of SP1, a Stress-Responsive, Boiling-Soluble, Homo-Oligomeric Protein from Aspen1

    Science.gov (United States)

    Wang, Wang-Xia; Pelah, Dan; Alergand, Tal; Shoseyov, Oded; Altman, Arie

    2002-01-01

    sp1 cDNA was isolated from aspen (Populus tremula) plants by immunoscreening an expression library using polyclonal antibodies against BspA protein. BspA, which is a boiling-stable protein, accumulates in aspen plants in response to water stress and abscisic acid application (Pelah et al., 1995). The sp1 cDNA was found to encode a 12.4-kD generally hydrophilic protein with a hydrophobic C terminus, which is different from the BspA protein and was termed SP1 (stable protein 1). Northern-blot analysis revealed that sp1 encodes a small mRNA (about 0.6 kb) that is expressed in aspen plants under non-stress conditions and is accumulated after salt, cold, heat, and desiccation stress, and during the recovery from stress. The SP1 detected in plants remained soluble upon boiling, migrated both as a 12.4-kD band and a much higher mass of 116 kD on a 17% (w/v) Tricine-sodium dodecyl sulfate-polyacrylamide gel. Comparative protease digestion patterns, amino acid analyses, and the N-terminal sequences of the 12.4- and 116-kD proteins revealed that SP1 is homo-oligomeric. Furthermore, gel filtration chromatography analysis indicated that SP1 exists in aspen plants as a complex, composed of 12 subunits of 12.4 kD. A large number of sequences deduced from expressed sequence tags and genomic sequences of other organisms with unknown function show high homology to SP1. Thus, SP1 may represent a new protein family. Here, we present the first report on this putative protein family: the cloning, isolation, and characterization of SP1, a stress-responsive, boiling-soluble, oligomeric protein. PMID:12376651

  8. 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.

  9. Developing Learner Centered Action Learning Model

    Directory of Open Access Journals (Sweden)

    Chalard Chantarasombat

    2011-01-01

    Full Text Available Problem statement: This study aimed to examine the effects of using Learner Centered Action Learning Model. The research was research and development by applying Participatory Action Research method. Instruments used were an achievement test, a questionnaire on students’ satisfaction and focused group discussion. Approach: The statistic included the Mean, Standard Deviation, effectiveness index and Dependent Sample t-test. The results revealed that the learning model had 2 Key factors: PAR with 6 stages and using the model with 21 sub activity together with learning activity organization showing efficiency in cognitive domain, psychomotor domain, affective domain, effectiveness index and learning retention. Result: The students showed their satisfaction at the highest Level. The factors of success included: Participation in actions of the participants and researcher, responsibility and learning climate. Conclusion: The factor of success in knowledge management outcome on Learner Centered Action Learning with the product after using Participatory Action Research aligned with learning activity implementation, consisted of Key aspects as: (1 the participation in performance practice, (2 the awareness, feeling, thinking, good attitude, responsibility in the course they were studying both of individual performance and group performance, (3 the persistence in acting for achieving common agreement, (4 the learning climate, the instructor was a facilitator encouraging for learning in program, including textbook of he course, media and instrument to search for, AAR and case study from the senor cohorts for comparing the quality of their performances, (5 the evaluation and conclusion of implementation in outcome Learner Centered Action Learning Model regarding to knowledge, feeling and skill of practice in field performance, (6 sharing among the students, instructors and learning network.

  10. Multicomponent aerosol dynamics model UHMA: model development and validation

    Directory of Open Access Journals (Sweden)

    H. Korhonen

    2004-01-01

    Full Text Available A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model was developed for studies of multicomponent tropospheric aerosol particles. The model includes major aerosol microphysical processes in the atmosphere with a focus on new particle formation and growth; thus it incorporates particle coagulation and multicomponent condensation, applying a revised treatment of condensation flux onto free molecular regime particles and the activation of nanosized clusters by organic vapours (Nano-Köhler theory, as well as recent parameterizations for binary H2SO4–H2O and ternary H2SO4–NH3-H2O homogeneous nucleation and dry deposition. The representation of particle size distribution can be chosen from three sectional methods: the hybrid method, the moving center method, and the retracking method in which moving sections are retracked to a fixed grid after a certain time interval. All these methods can treat particle emissions and transport consistently, and are therefore suitable for use in large scale atmospheric models. In a test simulation against an accurate high resolution solution, all the methods showed reasonable treatment of new particle formation with 20 size sections although the hybrid and the retracking methods suffered from artificial widening of the distribution. The moving center approach, on the other hand, showed extra dents in the particle size distribution and failed to predict the onset of detectable particle formation. In a separate test simulation of an observed nucleation event, the model captured the key qualitative behaviour of the system well. Furthermore, its prediction of the organic volume fraction in newly formed particles, suggesting values as high as 0.5 for 3–4 nm particles and approximately 0.8 for 10 nm particles, agrees with recent indirect composition measurements.

  11. Multicomponent aerosol dynamics model UHMA: model development and validation

    Directory of Open Access Journals (Sweden)

    H. Korhonen

    2004-01-01

    Full Text Available A size-segregated aerosol dynamics model UHMA (University of Helsinki Multicomponent Aerosol model was developed for studies of multicomponent tropospheric aerosol particles. The model includes major aerosol microphysical processes in the atmosphere with a focus on new particle formation and growth; thus it incorporates particle coagulation and multicomponent condensation, applying a revised treatment of condensation flux onto free molecular regime particles and the activation of nanosized clusters by organic vapours (Nano-Köhler theory, as well as recent parameterizations for binary H2SO4-H2O and ternary H2SO4-NH3-H2O homogeneous nucleation and dry deposition. The representation of particle size distribution can be chosen from three sectional methods: the hybrid method, the moving center method, and the retracking method in which moving sections are retracked to a fixed grid after a certain time interval. All these methods can treat particle emissions and atmospheric transport consistently, and are therefore suitable for use in large scale atmospheric models. In a test simulation against an accurate high resolution solution, all the methods showed reasonable treatment of new particle formation with 20 size sections although the hybrid and the retracking methods suffered from artificial widening of the distribution. The moving center approach, on the other hand, showed extra dents in the particle size distribution and failed to predict the onset of detectable particle formation. In a separate test simulation of an observed nucleation event, the model captured the key qualitative behaviour of the system well. Furthermore, its prediction of the organic volume fraction in newly formed particles, suggesting values as high as 0.5 for 3–4 nm particles and approximately 0.8 for 10 nm particles, agrees with recent indirect composition measurements.

  12. Developing a Forensic Continuous Audit Model

    Directory of Open Access Journals (Sweden)

    Grover S. Kearns

    2011-06-01

    Full Text Available Despite increased attention to internal controls and risk assessment, traditional audit approaches do not seem to be highly effective in uncovering the majority of frauds. Less than 20 percent of all occupational frauds are uncovered by auditors. Forensic accounting has recognized the need for automated approaches to fraud analysis yet research has not examined the benefits of forensic continuous auditing as a method to detect and deter corporate fraud. The purpose of this paper is to show how such an approach is possible. A model is presented that supports the acceptance of forensic continuous auditing by auditors and management as an effective tool to support the audit function, meet management’s regulatory objectives, and to combat fraud. An approach to developing such a system is presented.

  13. Engineering model development and test results

    Science.gov (United States)

    Wellman, John A.

    1993-08-01

    The correctability of the primary mirror spherical error in the Wide Field/Planetary Camera (WF/PC) is sensitive to the precise alignment of the incoming aberrated beam onto the corrective elements. Articulating fold mirrors that provide +/- 1 milliradian of tilt in 2 axes are required to allow for alignment corrections in orbit as part of the fix for the Hubble space telescope. An engineering study was made by Itek Optical Systems and the Jet Propulsion Laboratory (JPL) to investigate replacement of fixed fold mirrors within the existing WF/PC optical bench with articulating mirrors. The study contract developed the base line requirements, established the suitability of lead magnesium niobate (PMN) actuators and evaluated several tilt mechanism concepts. Two engineering model articulating mirrors were produced to demonstrate the function of the tilt mechanism to provide +/- 1 milliradian of tilt, packaging within the space constraints and manufacturing techniques including the machining of the invar tilt mechanism and lightweight glass mirrors. The success of the engineering models led to the follow on design and fabrication of 3 flight mirrors that have been incorporated into the WF/PC to be placed into the Hubble Space Telescope as part of the servicing mission scheduled for late 1993.

  14. Rolling Resistance Measurement and Model Development

    DEFF Research Database (Denmark)

    Andersen, Lasse Grinderslev; Larsen, Jesper; Fraser, Elsje Sophia;

    2015-01-01

    There is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by just a few percent will lead to substantial energy savings. This paper reviews the state of the art of rolling resistance research, focusing on measuring techniques, s......, surface and texture modeling, contact models, tire models, and macro-modeling of rolling resistance...

  15. LADEE Satellite Modeling and Simulation Development

    Science.gov (United States)

    Adams, Michael; Cannon, Howard; Frost, Chad

    2011-01-01

    As human activity on and around the Moon increases, so does the likelihood that our actions will have an impact on its atmosphere. The Lunar Atmosphere and Dust Environment Explorer (LADEE), a NASA satellite scheduled to launch in 2013, will orbit the Moon collecting composition, density, and time variability data to characterize the current state of the lunar atmosphere. LADEE will also test the concept of the "Modular Common Bus" spacecraft architecture, an effort to reduce both development time and cost by designing reusable, modular components for use in multiple missions with similar requirements. An important aspect of this design strategy is to both simulate the spacecraft and develop the flight code in Simulink, a block diagram-style programming language that allows easy algorithm visualization and performance testing. Before flight code can be tested, however, a realistic simulation of the satellite and its dynamics must be generated and validated. This includes all of the satellite control system components such as actuators used for force and torque generation and sensors used for inertial orientation reference. My primary responsibilities have included designing, integrating, and testing models for the LADEE thrusters, reaction wheels, star trackers, and rate gyroscopes.

  16. 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

    2012-10-01

    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 (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.

  17. Model Driven Development of Simulation Models: Defining and Transforming Conceptual Models into Simulation Models by Using Metamodels and Model Transformations

    NARCIS (Netherlands)

    Küçükkeçeci Çetinkaya, D.

    2013-01-01

    Modeling and simulation (M&S) is an effective method for analyzing and designing systems and it is of interest to scientists and engineers from all disciplines. This thesis proposes the application of a model driven software development approach throughout the whole set of M&S activities and it prop

  18. Simulation of partial oxidation of natural gas to synthesis gas using ASPEN PLUS

    Energy Technology Data Exchange (ETDEWEB)

    Khoshnoodi, M.; Lim, Y.S. [University of Sistan and Baluchestan, Zahedan (Iran). Dept. of Chemical Engineering

    1997-02-01

    The paper reports studies on the first stage of the SMDS Process for the conversion of natural gas to liquid fuels. In the SMDS process natural gas is first partially oxidized with pure oxygen to synthesis gas (a mixture of H{sub 2} and CO) which is then converted to high quality liquid transportation fuels by utilizing a modernized version of the Fischer-Tropsch reaction. The first stage of the process is synthesis gas production from natural gas. ASPEN PLUS equipped with a combustion databank was used for calculations. Concentrations of over 30 combustion species and radicals expected in the synthesis gas have been calculated at equilibrium and several non-equilibrium conditions. Using a sensitivity analysis tool, the relative feed flow rates and reactor parameters have been varied searching to maximize the CO/O{sub 2} yields as well as to minimize the undesired nitrogen compounds in the product stream. The optimum reactor temperature for maximizing the CO mode fraction in the synthesis gas was also calculated. 16 refs., 8 figs., 4 tabs.

  19. Developing Friction Stir Welding Process Model for ICME Application

    Science.gov (United States)

    Yang, Yu-Ping

    2015-01-01

    A framework for developing a product involving manufacturing processes was developed with integrated computational materials engineering approach. The key component in the framework is a process modeling tool which includes a thermal model, a microstructure model, a thermo-mechanical, and a property model. Using friction stir welding (FSW) process as an example, development of the process modeling tool was introduced in detail. The thermal model and the microstructure model of FSW of steels were validated with the experiment data. The model can predict reasonable temperature and hardness distributions as observed in the experiment. The model was applied to predict residual stress and joint strength of a pipe girth weld.

  20. Transcription factors in pancreatic development. Animal models.

    Science.gov (United States)

    Martin, Merce; Hauer, Viviane; Messmer, Mélanie; Orvain, Christophe; Gradwohl, Gérard

    2007-01-01

    Through the analysis of genetically modified mice a hierarchy of transcription factors regulating pancreas specification, endocrine destiny as well as endocrine subtype specification and differentiation has been established. In addition to conventional approaches such as transgenic technologies and gene targeting, recombinase fate mapping in mice has been key in establishing the lineage relationship between progenitor cells and their progeny in understanding pancreas formation. Moreover, the design of specific mouse models to conditionally express transcription factors in different populations of progenitor cells has revealed to what extent transcription factors required for islet cell development are also sufficient to induce endocrine differentiation and the importance of the competence of progenitor cells to respond to the genetic program implemented by these factors. Taking advantage of this basic science knowledge acquired in rodents, immature insulin-producing cells have recently been differentiated in vitro from human embryonic stem cells. Taken together these major advances emphasize the need to gain further in-depth knowledge of the molecular and cellular mechanisms controlling beta-cell differentiation in mice to generate functional beta-cells in the future that could be used for cell therapy in diabetes. PMID:17923766

  1. Variation in Trembling Aspen and White Spruce Wood Quality Grown in Mixed and Single Species Stands in the Boreal Mixedwood Forest

    Directory of Open Access Journals (Sweden)

    Francis De Araujo

    2015-05-01

    Full Text Available The Canadian boreal forest is largely represented by mixed wood forests of white spruce (Picea glauca (Moench Voss and trembling aspen (Populus tremuloides Michx. In this study, a total of 300 trees originating from three sites composed of trembling aspen and white spruce with varying compositions were investigated for wood quality traits: one site was composed mainly of aspen, one mainly of spruce and a third was a mixed site. Four wood quality traits were examined: wood density, microfibril angle (MFA, fibre characteristics, and cell wall chemistry. Social classes were also determined for each site in an attempt to provide a more in-depth comparison. Wood density showed little variation among sites for both species, with only significant differences occurring between social classes. The aspen site showed statistically lower MFAs than the aspen from the mixed site, however, no differences were observed when comparing spruce. Fibre characteristics were higher in the pure species sites for both species. There were no differences in carbohydrate contents across sites, while lignin content varied. Overall, the use of social classes did not refine the characterization of sites.

  2. Development of large Area Covering Height Model

    OpenAIRE

    Jacobsen, K.

    2014-01-01

    Height information is a basic part of topographic mapping. Only in special areas frequent update of height models is required, usually the update cycle is quite lower as for horizontal map information. Some height models are available free of charge in the internet; for commercial height models a fee has to be paid. Mostly digital surface models (DSM) with the height of the visible surface are given and not the bare ground height, as required for standard mapping. Nevertheless by fil...

  3. Architecture design in global and model-centric software development

    NARCIS (Netherlands)

    Heijstek, Werner

    2012-01-01

    This doctoral dissertation describes a series of empirical investigations into representation, dissemination and coordination of software architecture design in the context of global software development. A particular focus is placed on model-centric and model-driven software development.

  4. Applying mechanistic models in bioprocess development

    DEFF Research Database (Denmark)

    Lencastre Fernandes, Rita; Bodla, Vijaya Krishna; Carlquist, Magnus;

    2013-01-01

    The available knowledge on the mechanisms of a bioprocess system is central to process analytical technology. In this respect, mechanistic modeling has gained renewed attention, since a mechanistic model can provide an excellent summary of available process knowledge. Such a model therefore...

  5. Developments in vapour cloud explosion blast modeling

    NARCIS (Netherlands)

    Mercx, W.P.M.; Berg, A.C. van den; Hayhurst, C.J.; Robertson, N.J.; Moran, K.C.

    2000-01-01

    TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be

  6. Developing a Model of Occupational Choice

    Science.gov (United States)

    Egner, Joan Roos

    1974-01-01

    Rational and non-rational decision-making models of occupational choice are described. The Blau model provides an alternative to these. This model contains an occupational set of factors and a set related to the individual. Research supporting its conceptual utility and activities illustrating its pragmatic utility are discussed. (EAK)

  7. DEVELOPMENT OF TECHNOLOGIES AND ANALYTICAL CAPABILITIES FOR VISION 21 ENERGY PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Madhava Syamlal, Ph.D.

    2002-04-01

    A software review meeting was held at Fluent Inc. in Lebanon, NH on January 31-February 1, 2002. The team reviewed the current status of the software and its compliance with the software requirements (Task 2). Work on a fuel cell based power-plant flow sheet that incorporates a reformer CFD model was started. This test case includes more features (multiple ports, temperature dependent properties) than the mixing tank test case developed earlier and will be used for the further testing of the software (Task 2). The software development plan was finalized (Task 2.7). The design and implementation of a CFD database was commenced. The CFD database would store various models that a process analyst can use in the flowsheet model (Task 2.8). The COM-CORBA Bridge was upgraded to use the recently published version 0.9.3 CAPE-OPEN specifications. Work on transferring reaction kinetics data from Aspen Plus to Fluent was started (Task 2.11). The requirements for extending CAPE-OPEN interfaces in Aspen Plus to transfer temperature dependent properties to Fluent was written and communicated to the Aspen Tech developer of CAPE-OPEN interfaces (Task 2.12). A prototype of low-order model based on the Multiple Regression technique was written. A low-order model is required to speed up the calculations with the integrated model (Task 2.19). The Berkshire Power (Agawam, MA) combined-cycle power plant was selected as the Demonstration Case 2 (Task 3.2). A CFD model of the furnace in Demonstration Case 1 was developed. The furnace model will be incorporated into the flowsheet model already developed for this case (Task 4.1). A new hire joined the Fluent development team for this project. The project management plan was revised based on the software development plan. A presentation on the project status was made at the Clearwater Conference, March 4-7, 2002. The final manuscript for ESCAPE-12 conference was submitted (Task 7.0).

  8. DEVELOPMENT OF TECHNOLOGIES AND ANALYTICAL CAPABILITIES FOR VISION 21 ENERGY PLANTS

    International Nuclear Information System (INIS)

    To complete project planning, various project groups conducted several meetings and teleconferences. As a result a draft project management plan was written and circulated. The plan will be finalized in a project kick off meeting to be held on January 16, 2001 in Lebanon, NH, which will be attended by all project participants (Task 1.0). Various project personnel have been trained in the use of Fluent and Aspen Plus, which completes all the training tasks except for Aspen Plus and IDL training for Alstom Power (Task 2.1). A preliminary version of User Requirements Document (preURD) was written. This document will be sent to key users of Aspen Plus and FLUENT and their responses will be collected in January (Task 2.3). A prototype of Fluent integration with Aspen Plus was constructed for understanding the required software design. The development of a general architecture for the integrated software suite has been started (Task 2.6). Invitation letters for participation in an Advisory Board were sent out to several Vision 21 contractors. Their responses will be used to form an Advisory Board in January (Task 5.0). Fluent has awarded subcontracts to Alstom Power, CERC, and Aspen Tech and negotiations with Intergraph are underway. Aspen Plus and FLUENT were installed on a computer at CERC. The design of a project web site was completed, and the site setup was started (Task 7.0)

  9. Development of a generic activities model of command and control

    OpenAIRE

    Stanton, NA; Baber, C; Walker, GH; Houghton, RJ; McMaster, R.; Stewart, R; Harris, D.; Jenkins, DP; Young, MS; Salmon, PM

    2008-01-01

    This paper reports on five different models of command and control. Four different models are reviewed: a process model, a contextual control model, a decision ladder model and a functional model. Further to this, command and control activities are analysed in three distinct domains: armed forces, emergency services and civilian services. From this analysis, taxonomies of command and control activities are developed that give rise to an activities model of command and control. This model w...

  10. International orientation on methodologies for modelling developments in road safety.

    NARCIS (Netherlands)

    Reurings, M.C.B. & Commandeur, J.J.F.

    2007-01-01

    This report gives an overview of the models developed in countries other than the Netherlands to evaluate past developments in road traffic safety and to obtain estimates of these developments in the future. These models include classical linear regression and loglinear models as applied in Great Br

  11. Development of an Instructional Quality Assurance Model in Nursing Science

    Science.gov (United States)

    Ajpru, Haruthai; Pasiphol, Shotiga; Wongwanich, Suwimon

    2011-01-01

    The purpose of this study was to develop an instructional quality assurance model in nursing science. The study was divided into 3 phases; (1) to study the information for instructional quality assurance model development (2) to develop an instructional quality assurance model in nursing science and (3) to audit and the assessment of the developed…

  12. Aqueous Solution Vessel Thermal Model Development II

    Energy Technology Data Exchange (ETDEWEB)

    Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-28

    The work presented in this report is a continuation of the work described in the May 2015 report, “Aqueous Solution Vessel Thermal Model Development”. This computational fluid dynamics (CFD) model aims to predict the temperature and bubble volume fraction in an aqueous solution of uranium. These values affect the reactivity of the fissile solution, so it is important to be able to calculate them and determine their effects on the reaction. Part A of this report describes some of the parameter comparisons performed on the CFD model using Fluent. Part B describes the coupling of the Fluent model with a Monte-Carlo N-Particle (MCNP) neutron transport model. The fuel tank geometry is the same as it was in the May 2015 report, annular with a thickness-to-height ratio of 0.16. An accelerator-driven neutron source provides the excitation for the reaction, and internal and external water cooling channels remove the heat. The model used in this work incorporates the Eulerian multiphase model with lift, wall lubrication, turbulent dispersion and turbulence interaction. The buoyancy-driven flow is modeled using the Boussinesq approximation, and the flow turbulence is determined using the k-ω Shear-Stress-Transport (SST) model. The dispersed turbulence multiphase model is employed to capture the multiphase turbulence effects.

  13. A Social Development Practice Model for Community Development.

    Science.gov (United States)

    Abrahams, Caryl

    1992-01-01

    The community practice model illustrates how goals of participation, empowerment, cooperation, and institutionalization are affected by inputs from human resources, program characteristics, finances, social costs, and policy requirements within the context of the social, economic, and political structure; population diversity; physical…

  14. Process optimization for bioethanol conversion to bioethylene using ASPEN PLUS%基于ASPEN PLUS平台的生物乙醇制生物乙烯的工艺优化

    Institute of Scientific and Technical Information of China (English)

    王林; 崔国燊; 徐檬; 谭天伟

    2009-01-01

    生物乙醇与生物乙烯的过程耦合是降低生物乙烯成本的重要途径.在充分分析生物乙醇制乙烯工艺的特点后,以ASPEN PLUS模拟软件为平台,对乙醇分离与乙醇脱水反应过程的耦合进行了优化设计,优化后的工艺流程节省蒸汽73%,节省能耗6%.

  15. Study on vent washing and waste-heat recovery of DAP plant based on ASPEN PLUS%基于ASPEN PLUS的磷酸二铵装置尾气洗涤及余热回收研究

    Institute of Scientific and Technical Information of China (English)

    田静; 莫春萍; 王万林; 张秀芳; 郑建国

    2014-01-01

    利用脱盐水间接冷凝尾气中的水蒸气以减少白雾的排放和回收尾气的低温位余热,同时使用ASPEN PLUS软件对尾气洗涤塔及余热回收过程进行模拟.结果表明,该软件模拟结果与现场测量参数较为吻合,可用于指导生产,并为装置改造提供依据.

  16. Simulation Modeling of Software Development Processes

    Science.gov (United States)

    Calavaro, G. F.; Basili, V. R.; Iazeolla, G.

    1996-01-01

    A simulation modeling approach is proposed for the prediction of software process productivity indices, such as cost and time-to-market, and the sensitivity analysis of such indices to changes in the organization parameters and user requirements. The approach uses a timed Petri Net and Object Oriented top-down model specification. Results demonstrate the model representativeness, and its usefulness in verifying process conformance to expectations, and in performing continuous process improvement and optimization.

  17. Development of Orthotopic Pancreatic Tumor Mouse Models

    OpenAIRE

    Qiu, Wanglong; Gloria H. Su

    2013-01-01

    Genetically engineered mouse models of pancreatic cancer that recapitulate human pancreatic tumorigenesis have been established. However, the cost associated with generating and housing these mice can be prohibitive. Tumor latency and progression to invasive diseases in these models are also highly variable. Xenograft mouse models of human pancreatic cancer including heterotopic and orthotopic have been widely used in preclinical studies for their comparatively low cost and rapid, predictable...

  18. Modelling Anxiety in Humans for Drug Development

    OpenAIRE

    Siepmann, Martin; Joraschky, Peter

    2007-01-01

    Animal behavioural profiles are commonly employed to investigate new therapeutic agents to treat anxiety disorders as well as to investigate the mechanism of action of anxiolytic drugs. However, many clinically important symptoms of anxiety can not be modelled directly in animals. Human models of anxiety should bridge between animal models and anxiety disorders. Experimental anxiety states in humans can be induced by either pharmacological means such as CO2 inhalation or psychological means s...

  19. Simulation by Aspen Plus on desolventizing of crude oil in soybean protein extracting process with reverse micelles%用 Aspen Plus 模拟反胶束萃取大豆蛋白过程中毛油脱溶操作

    Institute of Scientific and Technical Information of China (English)

    王鑫; 于国萍; 杜成亮; 吴志光

    2013-01-01

    distillation column, and the heat load of the reboiler and the condenser were analyzed. A generalized model (based on the NRTL model) for estimation of activity coefficients is applied to the simulation of the extraction process. The equilibrium stage model based on the RADFRAC module of Aspen Plus is employed for the steady-state simulation of the improved process flowsheet, and therefore rigorous simulations allow the appropriate operating conditions to be established in the separating process. It is shown in the results that the reflux ratio of the vacuum distillation was 0.352, the distillate flow was 10.348 kg/h, and the purity of the oil and solvent can be 98.9% and 99.7% respectively, while the actual heat loads of the reboiler and the condenser were 1398.824 W and -1626.226 W, respectively. According to the sensitivity analysis, the concentration of oil and solvent grew respectively with the number of stages, and the optimal number of stages was seven. The cost was analyzed based on simulation calculations, in which the annual cost savings was¥1 272 000. As an alternative to control the purity of solvent and soybean oil, the spirit distillation unit was highly efficient in the case of low contamination and production costs. Moreover, the reflux ratio and product flow rate have an important influence on the purity of spirit composition. The key parameters were provided for unit operations separating organic solvent from soybean oil. The technical key points for the industrialized installation design were discussed to provide reliable data for enlarged desolventizing devices in the industrial field.

  20. Carbon isotope discrimination and water stress in trembling aspen following variable retention harvesting.

    Science.gov (United States)

    Bladon, Kevin D; Silins, Uldis; Landhäusser, Simon M; Messier, Christian; Lieffers, Victor J

    2007-07-01

    Variable retention harvesting (VRH) has been proposed as a silvicultural practice to maintain biodiversity and ecosystem integrity. No previous study has examined tree carbon isotope discrimination to provide insights into water stress that could lead to dieback and mortality of trees following VRH. We measured and compared the carbon isotope ratios (delta(13)C) in stem wood of trembling aspen (Populus tremuloides Michx.) before and after VRH. Eight trees were sampled from isolated residual, edge and control (interior of unharvested stand) positions from each of seven plots in three regions (Calling Lake and Drayton Valley, Alberta and Lac Duparquet, Québec). After VRH, the general trend in mean delta(13)C was residual > edge > control trees. Although this trend is indicative of water stress in residual trees, it also suggests that edge trees received some sheltering effect, reducing their stress compared with that of residuals. A strong inverse relationship was found between the delta(13)C values and the mean annual precipitation in each region. The trend in mean delta(13)C signature was Calling Lake > Drayton Valley > Lac Duparquet trees. These results suggest that residual or edge trees in drier regions are more likely to suffer water stress following VRH. We also observed a trend of greater delta(13)C in stout trees compared with slender trees, both before and after VRH. The evidence of greater water stress in stout trees likely occurred because of a positive relationship between stem diameter and crown volume per basal area. Our results provide evidence that water stress could be the driving mechanism leading to dieback and mortality of residual trees shortly after VRH. Additionally, the results from edge trees indicate that leaving hardwood residuals in larger patches or more sheltered landscape positions could reduce the water stress to which these trees are subjected, thereby reducing dieback and mortality. PMID:17403660

  1. Evolving Leaders. A Model for Promoting Leadership Development in Programs.

    Science.gov (United States)

    Palus, Charles J.; Drath, Wilfred H.

    A new model for promoting leadership development in programs emphasizes individuals' psychological development. The model, which is intended for use by individuals responsible for leadership development in organizations or by leadership development program planners/evaluators, is based on a cyclic process of three time-linked categories: readiness…

  2. Developing mobile educational apps: development strategies, tools and business models

    Directory of Open Access Journals (Sweden)

    Serena Pastore

    Full Text Available The mobile world is a growing and evolving market in all its aspects from hardware, networks, operating systems and applications. Mobile applications or apps are becoming the new frontier of software development, since actual digital users use mobile devi ...

  3. Developing an Implementing Teacher Directed Professional Development Model.

    Science.gov (United States)

    Baden, Donald J.

    Teacher directed inservice or professional development is one means of increasing teacher self improvement. However, unless the teacher motivation stems from an intrinsic desire to teach more effectively, the degree of professional growth will be minimal. For this reason it is imperative that a teacher directed inservice program depend on…

  4. Development of the Integrated Communication Model

    Science.gov (United States)

    Ho, Hua-Kuo

    2008-01-01

    Human communication is a critical issue in personal life. It also should be the indispensable core element of general education curriculum in universities and colleges. Based on literature analysis and the author's clinical observation, the importance of human communication, functions of model, and often seen human communication models were…

  5. Development of a Model for Technology Strategy Elaboration

    Directory of Open Access Journals (Sweden)

    Aliakbar Mazlomi

    2011-02-01

    Full Text Available Considering the role of industry in the economy, especially the developed countries and countries with automobile (automotive industry seems to be necessary to develop technology development strategy. In this paper a model by choosing appropriate technology development strategy to how good we are. (So review existing models and evaluate their strengths and weaknesses of the measure applied in the industry with the closest model industry conditions is consistent with the practices were selected and other factors as the failure of this model was determined it developed a new model for strategy ispresented

  6. 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.

  7. Root mass, net primary production and turnover in aspen, jack pine and black spruce forests in Saskatchewan and Manitoba, Canada.

    Science.gov (United States)

    Steele, Sarah J.; Gower, Stith T.; Vogel, Jason G.; Norman, John M.

    1997-01-01

    Root biomass, net primary production and turnover were studied in aspen, jack pine and black spruce forests in two contrasting climates. The climate of the Southern Study Area (SSA) near Prince Albert, Saskatchewan is warmer and drier in the summer and milder in the winter than the Northern Study Area (NSA) near Thompson, Manitoba, Canada. Ingrowth soil cores and minirhizotrons were used to quantify fine root net primary production (NPPFR). Average daily fine root growth (m m(-2) day(-1)) was positively correlated with soil temperature at 10-cm depth (r(2) = 0.83-0.93) for all three species, with black spruce showing the strongest temperature effect. At both study areas, fine root biomass (measured from soil cores) and fine root length (measured from minirhizotrons) were less for jack pine than for the other two species. Except for the aspen stands, estimates of NPPFR from minirhizotrons were significantly greater than estimates from ingrowth cores. The core method underestimated NPPFR because it does not account for simultaneous fine root growth and mortality. Minirhizotron NPPFR estimates ranged from 59 g m(-2) year(-1) for aspen stands at SSA to 235 g m(-2) year(-1) for black spruce at NSA. The ratio of NPPFR to total detritus production (aboveground litterfall + NPPFR) was greater for evergreen forests than for deciduous forests, suggesting that carbon allocation patterns differ between boreal evergreen and deciduous forests. In all stands, NPPFR consistently exceeded annual fine root turnover and the differences were larger for stands in the NSA than for stands in the SSA, whereas the difference between study areas was only significant for black spruce. The imbalance between NPPFR and fine root turnover is sufficient to explain the net accumulation of carbon in boreal forest soils. PMID:14759831

  8. Aspen软件在大型聚乙烯装置上的应用%Application of Aspen software in large-scale polyethylene plant

    Institute of Scientific and Technical Information of China (English)

    王文庆; 李延辉

    2004-01-01

    以线型低密度聚乙烯装置产品牌号切换时的露点计算为例,对采用AspenTech公司的Aspen P1us、InfoPlus.21软件的应用进行了研究与分析.使用Aspen软件可以实现露点等物性数据的实时计算,为安全、稳定地进行产品牌号切换提供准确的依据;而且,可以使用Visual Basic语言将Aspen Plus的输入数据和模拟结果与其他应用程序相连接,实现全自动的数据采集与计算.

  9. Towards a controlled sensitivity analysis of model development decisions

    Science.gov (United States)

    Clark, Martyn; Nijssen, Bart

    2016-04-01

    The current generation of hydrologic models have followed a myriad of different development paths, making it difficult for the community to test underlying hypotheses and identify a clear path to model improvement. Model comparison studies have been undertaken to explore model differences, but these studies have not been able to meaningfully attribute inter-model differences in predictive ability to individual model components because there are often too many structural and implementation differences among the models considered. As a consequence, model comparison studies to date have provided limited insight into the causes of differences in model behavior, and model development has often relied on the inspiration and experience of individual modelers rather than a systematic analysis of model shortcomings. This presentation will discuss a unified approach to process-based hydrologic modeling to enable controlled and systematic analysis of multiple model representations (hypotheses) of hydrologic processes and scaling behavior. Our approach, which we term the Structure for Unifying Multiple Modeling Alternatives (SUMMA), formulates a general set of conservation equations, providing the flexibility to experiment with different spatial representations, different flux parameterizations, different model parameter values, and different time stepping schemes. We will discuss the use of SUMMA to systematically analyze different model development decisions, focusing on both analysis of simulations for intensively instrumented research watersheds as well as simulations across a global dataset of FLUXNET sites. The intent of the presentation is to demonstrate how the systematic analysis of model shortcomings can help identify model weaknesses and inform future model development priorities.

  10. ASPEN PLUS对混合二甲苯分离工艺的分析研究

    Institute of Scientific and Technical Information of China (English)

    刘春法; 孙剑; 阮栋

    2005-01-01

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

  11. Interface between MATLAB and Aspen Plus Based on COM Technology and its Advanced Application%基于COM技术的MATLAB与AsPen Plus接口及高级应用

    Institute of Scientific and Technical Information of China (English)

    耿大钊; 陈曦; 邵之江; 钱积新

    2006-01-01

    基于COM技术研制开发了MATLAB和Aspen Plus的接口工具箱MAP,实现了在MATLAB环境下对Aspen Plus中数据进行读写操作,并控制模拟的运行.MAP接口将MATLAB计算能力和Aspen Plus的模拟能力结合在一起,扩展了Aspen Plus的高级应用.通过精馏塔进料软测量的示例,阐述了如何通过MAP接口来调用自主开发的禁忌搜索优化算法,解决由于Aspen Plus中的优化算法的局限性所无法实现的模拟与优化问题.

  12. Development Model of Rural Industrialization in China

    OpenAIRE

    Chen, Weihong; Zhang, Ruide; Liu, Guichuan

    2009-01-01

    With the implementation of the policy of expanding domestic demand, farmers have become the main body of rural economy and rural industrialization. Development of rural industrialization promotes the development of rural economy in China, effectively transfers the surplus labor force in rural areas, continuously optimizes the rural economic structure, improves the living standard of farmers, and has made important contributions to the stability and development of economy and society in China....

  13. Business models for sustainable energy development

    OpenAIRE

    Kolk, A.; Buuse, van den, D.

    2013-01-01

    Business-led approaches to accessing energy in development countries are becoming key factors to sustainable market development. Given the major challenges in this market, companies will blend commercial and donor-funded activities, while simultaneously finding innovative ways to bring renewable energy technologies beyond the energy grid. Collaborative approaches by companies and public actors focused on private sector development seem crucial at this stage to further upscale emerging busines...

  14. Modeling human brain development with cerebral organoids

    OpenAIRE

    Muzio, Luca; Consalez, G. Giacomo

    2013-01-01

    The recent discovery of a new three-dimensional culture system for the derivation of cerebral organoids from human induced pluripotent stem cells provides developmental neurobiologists with the first example of a three-dimensional framework for the study of human brain development. This innovative approach permits the in vitro assembly of a human embryonic brain rudiment that recapitulates the developing human cerebrum. Organoids contain progenitor populations that develop to yield mature cor...

  15. Parallel Development of Products and New Business Models

    DEFF Research Database (Denmark)

    Lund, Morten; Hansen, Poul H. Kyvsgård

    2014-01-01

    functions and new concepts. These chances can be captured in various generations of practice. This paper will discuss the recent development of 3rd generation product development process models and the emergence of a 4th generation. While the 3rd generation models included the concept of innovation...... and innovation management the 4th generation models are increasingly including the concept business models and business model innovation....

  16. ADAPTIVE GUIDANCE MODEL BASED SIMILARITY FOR SOFTWARE PROCESS DEVELOPMENT

    OpenAIRE

    Hamid Khemissa; Mohamed Ahmed-nacer; Abdelkader Belkhir

    2014-01-01

    This paper describes a modeling approach SAGM (Similarity for Adaptive Guidance Model) that provides adaptive and recursive guidance for software process development. This approach, in accordance to developer needs, allows specific tailored guidance regarding the profile of developers. A profile is partially or completely defined from a model of developers, through their roles, their qualifications, and through the relationships between the context of the current activity and the ...

  17. Business models for sustainable energy development

    NARCIS (Netherlands)

    A. Kolk; D. van den Buuse

    2013-01-01

    Business-led approaches to accessing energy in development countries are becoming key factors to sustainable market development. Given the major challenges in this market, companies will blend commercial and donor-funded activities, while simultaneously finding innovative ways to bring renewable ene

  18. Aspen simulation of chlorine and hydrogen chloride absorption system%基于Aspen的氯气、氯化氢气体吸收系统的模拟

    Institute of Scientific and Technical Information of China (English)

    王银亮; 刘军

    2016-01-01

    采用Aspen Plus对某项目氯气、氯化氢气体吸收系统进行了稳态模拟,并对吸收剂的用量进行了优化;在得到基础数据的基础上,利用Aspen HYSYS对该吸收系统进行了动态模拟,明确了部分参数的变化对吸收率产生的影响,对项目开车及员工培训方案的制定具有重要的参考作用.

  19. 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...... of ground wood by 300–400%, compared to the initial raw material. Pretreatment with a 4.8% aqueous solution of nitric acid (125°C, 1.8 MPa, 10 min) is shown to be most effective, as it increases the reactivity of the ground aspen wood by more than 500%....

  20. 化工流程模拟软件Aspen Plus在湿法冶金学教学中的应用%Application of Aspen Plus in the Teaching Process of Hydrometallurgy

    Institute of Scientific and Technical Information of China (English)

    蓝德均

    2011-01-01

    The relationship between the chemical process simulation software,ASPEN Plus and the teaching process of Hydrometallurgy was discussed in detail.Introduction of ASPEN into the teaching process of Hydrometallurgy was practical completely,which was contributed to impart knowledge into students for improving teaching effect in the process of theoretical teaching,and to enhance the practice of Hydrometallurgy for the last goal of the course,and to give students the convenient fast simple pre-training of the job before working.%详细讨论了化工流程模拟软件ASPEN与湿法冶金学教学的关系。ASPEN软件的引入对于湿法冶金教学过程是完全可行的。这即有利于理论教学过程中对知识的灌输,改善教学效果,也有利于增强课程的实践环节,强化课程教学的最终目的,更可以使学生得到方便、快速、简单地就业前的岗位预训练。