WorldWideScience

Sample records for model nox storage

  1. Sulfur Deactivation of NOx Storage Catalysts: A Multiscale Modeling Approach

    Directory of Open Access Journals (Sweden)

    Rankovic N.

    2013-09-01

    Full Text Available Lean NOx Trap (LNT catalysts, a promising solution for reducing the noxious nitrogen oxide emissions from the lean burn and Diesel engines, are technologically limited by the presence of sulfur in the exhaust gas stream. Sulfur stemming from both fuels and lubricating oils is oxidized during the combustion event and mainly exists as SOx (SO2 and SO3 in the exhaust. Sulfur oxides interact strongly with the NOx trapping material of a LNT to form thermodynamically favored sulfate species, consequently leading to the blockage of NOx sorption sites and altering the catalyst operation. Molecular and kinetic modeling represent a valuable tool for predicting system behavior and evaluating catalytic performances. The present paper demonstrates how fundamental ab initio calculations can be used as a valuable source for designing kinetic models developed in the IFP Exhaust library, intended for vehicle simulations. The concrete example we chose to illustrate our approach was SO3 adsorption on the model NOx storage material, BaO. SO3 adsorption was described for various sites (terraces, surface steps and kinks and bulk for a closer description of a real storage material. Additional rate and sensitivity analyses provided a deeper understanding of the poisoning phenomena.

  2. Update on microkinetic modeling of lean NOx trap chemistry.

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Richard S.; Daw, C. Stuart (Oak Ridge National Laboratory, Oak Ridge, TN); Pihl, Josh A. (Oak Ridge National Laboratory, Oak Ridge, TN); Choi, Jae-Soon (Oak Ridge National Laboratory, Oak Ridge, TN); Chakravarthy, V, Kalyana (Oak Ridge National Laboratory, Oak Ridge, TN)

    2010-04-01

    Our previously developed microkinetic model for lean NOx trap (LNT) storage and regeneration has been updated to address some longstanding issues, in particular the formation of N2O during the regeneration phase at low temperatures. To this finalized mechanism has been added a relatively simple (12-step) scheme that accounts semi-quantitatively for the main features observed during sulfation and desulfation experiments, namely (a) the essentially complete trapping of SO2 at normal LNT operating temperatures, (b) the plug-like sulfation of both barium oxide (NOx storage) and cerium oxide (oxygen storage) sites, (c) the degradation of NOx storage behavior arising from sulfation, (d) the evolution of H2S and SO2 during high temperature desulfation (temperature programmed reduction) under H2, and (e) the complete restoration of NOx storage capacity achievable through the chosen desulfation procedure.

  3. Lean NOx Trap Modeling in Vehicle Systems Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming [ORNL; Chakravarthy, Veerathu K [ORNL; Daw, C Stuart [ORNL; Conklin, Jim [ORNL

    2010-09-01

    A one-dimensional model for simulating lean NOx trap (LNT) performance is developed and validated using both steady state cycling data and transient data from FTP testing cycles. The model consists of the conservation equations for chemical species and energy in the bulk flow, energy of the solid walls, O2 storage and NOx storage (in the form of nitrites and nitrates). Nitrites and nitrates are formed by diffusion of NO and NO2, respectively, into sorbent particles (assumed to be hemi-spherical in shape) along with O2 and their formation rates are controlled by chemical kinetics as well as solid-phase diffusion rates of NOx species. The model also accounts for thermal aging and sulfation of LNTs. Empirical correlations are developed on the basis of published experimental data to capture these effects. These empirical correlations depend on total mileage for which the LNT has been in use, the mileage accumulated since the last desulfation event in addition to the freshly degreened catalyst characteristics. The model has been used in studies of vehicle systems (integration, performance etc.) including hybrid powertrain configurations. Since the engines in hybrid vehicles turn on and off multiple number of times during single drive cycles, the exhaust systems may encounter multiple cold start transients. Accurate modeling of catalyst warm-up and cooling is, therefore, very important to simulate LNT performance in such vehicles. For this purpose, the convective heat loss from the LNT to the ambient is modeled using a Nusselt number correlation that includes effects of both forced convection and natural convection (with later being important when vehicle is stationary). Using the model, the fuel penalty associated with operating LNTs on small diesel engine powered car during FTP drive cycles is estimated.

  4. Combining nonthermal plasma with perovskite-like catalyst for NOx storage and reduction.

    Science.gov (United States)

    Peng, Han Hsuan; Pan, Kuan Lun; Yu, Sheng Jen; Yan, Shaw Yi; Chang, Moo Been

    2016-10-01

    A new NOx storage and reduction (NSR) system is developed for NOx removal by combining perovskite-like catalyst with nonthermal plasma technology. In this hybrid system, catalyst is mainly used for oxidizing NO to NO2 and storing them, while nonthermal plasma is applied as a desorption-reduction step for converting NOx into N2. An innovative catalyst with a high NOx storage capacity and good reduction performance is developed by successive impregnation. The catalysts prepared with various metal oxides were investigated for NOx storage capacity (NSC) and NOx conversion. Characterization of the catalysts prepared reveals that addition of cobalt (Co) and potassium (K) considerably increases the performance for NSC. Results also show that SrKMn0.8Co0.2O4 supported on BaO/Al2O3 has good NSC (209 μmol/gcatalyst) for the gas stream containing 500 ppm NO and 5 % O2 with N2 as carrier gas. For plasma reduction process, NOx conversion achieved with SrKMn0.8Co0.2O4/BaO/Al2O3 reaches 81 % with the applied voltage of 12 kV and frequency of 6 kHz in the absence of reducing agents. The results indicate that performance of plasma reduction process (81 %) is better than that of thermal reduction (64 %). Additionally, mixed gases including 1 % CO, 1 % H2 and 1 % CH4, and 2 % H2O(g) are simultaneously introduced into the system to investigate the effect on NSR with plasma system and results indicate that performance of NSR with plasma can be enhanced. Overall, the hybrid system is promising to be applied for removing NOx from gas streams. Graphical abstract ᅟ.

  5. Sulfate Storage and Stability on Common Lean NOx Trap Components

    Energy Technology Data Exchange (ETDEWEB)

    Ottinger, Nathan A [ORNL; Toops, Todd J [ORNL; Pihl, Josh A [ORNL; Roop, Justin T [ORNL; Choi, Jae-Soon [ORNL; Partridge Jr, William P [ORNL

    2012-01-01

    Components found in a commercial lean NO{sub x} trap have been studied in order to determine their impact on sulfate storage and release. A micro-reactor and a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) were used to compare components MgAl{sub 2}O{sub 4}, Pt/MgAl{sub 2}O{sub 4}, Pt/Al{sub 2}O{sub 3}, Pt/Ba/Al{sub 2}O{sub 3}, Pt/CeO{sub 2}-ZrO{sub 2}, and Pt/Ba/CeO{sub 2}-ZrO{sub 2}, as well as physical mixtures of Pt/Al{sub 2}O{sub 3} + MgAl{sub 2}O{sub 4} and Pt/Ba/CeO{sub 2}-ZrO{sub 2} + MgAl{sub 2}O{sub 4}. Desulfation temperature profiles as well as DRIFTS NO{sub x} and SO{sub x} storage spectra are presented for all components. This systematic approach highlighted the ability of the underlying support to impact sulfate stability, in particular when Ba was supported on ceria-zirconia rather than alumina the desulfation temperature decreased by 60-120 C. A conceptual model of sulfation progression on the ceria-zirconia support is proposed that explains the high uptake of sulfur and low temperature release when it is employed. It was also determined that the close proximity of platinum is not necessary for much of the sulfation and desulfation chemistry that occurs, as physical mixtures with platinum dispersed on only one phase displayed similar behavior to samples with platinum dispersed on both phases.

  6. Multifunctional catalyst for maximizing NOx oxidation/storage/reduction: The role of the different active sites

    OpenAIRE

    Palomares Gimeno, Antonio Eduardo; UZCATEGUI PAREDES, ALVARO; Franch Martí, Cristina; Corma Canós, Avelino

    2013-01-01

    A multifunctional catalyst/storage material has been prepared to maximize NOx removal. This material is based on mixed oxides derived from modified layered double hydrotalcites (LDH). A cobalt catalytic function oxidizes the NO to NO2. The NO2 is stored as nitrate in the basic sites of the material. The basic properties of the Co/Mg/Al mixed oxide derived from LDH were enhanced by doping with sodium, improving the storage capacity of the catalyst. Finally, the introduction of vanadium sites, ...

  7. Hydrotalcite-derived MnxMg3-xAlO catalysts used for soot combustion, NOx storage and simultaneous soot-NOx removal.

    Science.gov (United States)

    Li, Qian; Meng, Ming; Xian, Hui; Tsubaki, Noritatsu; Li, Xingang; Xie, Yaning; Hu, Tiandou; Zhang, Jing

    2010-06-15

    The hydrotalcite-based Mn(x)Mg(3-x)AlO catalysts with different Mn:Mg atomic ratios were synthesized by coprecipitation, and employed for soot combustion, NOx storage and simultaneous soot-NO(x) removal. It is shown that with the increase of Mn content in the hydrotalcite-based Mn(x)Mg(3-x)AlO catalysts the major Mn-related species vary from MnAl(2)O(4) and Mg(2)MnO(4) to Mn(3)O(4) and Mn(2)O(3). The catalyst Mn(1.5)Mg(1.5)AlO displays the highest soot combustion activity with the temperature for maximal soot combustion rate decreased by 210 degrees C, as compared with the Mn-free catalyst. The highly reducible Mn(4+) ions in Mg(2)MnO(4) are identified as the most active species for soot combustion. For NO(x) storage, introduction of Mn greatly influences bulk NO(x) storage, with the adsorbed NO(x) species varying from linear nitrites to ionic and chelating bidentate nitrates gradually. The coexistence of highly oxidative Mn(4+) and highly reductive Mn(2+) in Mn(1.0)Mg(2.0)AlO is favorable to the simultaneous soot-NO(x) removal, giving a NO(x) reduction percentage of 24%. In situ DRIFTS reveals that the ionic nitrate species are more reactive with soot than nitrites and chelating bidentate nitrates, showing higher NO(x) reduction efficiency.

  8. Kinetic and Performance Studies of the Regeneration Phase of Model Pt/Ba/Rh NOx Traps for Design and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Michael Harold; Vemuri Balakotaiah

    2010-05-31

    In this project a combined experimental and theoretical approach was taken to advance our understanding of lean NOx trap (LNT) technology. Fundamental kinetics studies were carried out of model LNT catalysts containing variable loadings of precious metals (Pt, Rh), and storage components (BaO, CeO{sub 2}). The Temporal Analysis of Products (TAP) reactor provided transient data under well-characterized conditions for both powder and monolith catalysts, enabling the identification of key reaction pathways and estimation of the corresponding kinetic parameters. The performance of model NOx storage and reduction (NSR) monolith catalysts were evaluated in a bench scale NOx trap using synthetic exhaust, with attention placed on the effect of the pulse timing and composition on the instantaneous and cycle-averaged product distributions. From these experiments we formulated a global model that predicts the main spatio-temporal features of the LNT and a mechanistic-based microkinetic models that incorporates a detailed understanding of the chemistry and predicts more detailed selectivity features of the LNT. The NOx trap models were used to determine its ability to simulate bench-scale data and ultimately to evaluate alternative LNT designs and operating strategies. The four-year project led to the training of several doctoral students and the dissemination of the findings as 47 presentations in conferences, catalysis societies, and academic departments as well 23 manuscripts in peer-reviewed journals. A condensed review of NOx storage and reduction was published in an encyclopedia of technology.

  9. Development of chemical kinetic models for lean NOx traps.

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Richard S.

    2010-04-01

    Overall project goal: Obtain the fundamental surface chemistry knowledge needed for the design and optimal utilization of NOx trap catalysts, thereby helping to speed the widespread adoption of this technology. Relevance to VT Program goals: Effective, durable advanced aftertreatment systems for lean-burn engines must be available if the fuel economy advantages of these engines are to be realized. Specific current year objective: Identify and correct any deficiencies in the previously developed reaction mechanism describing normal storage/regeneration cycles, and complete development of a supplementary mechanism accounting for the effects of sulfation. A fundamental understanding of LNT chemistry is needed to realize the full potential of this aftertreatment technology, which could lead to greater use of fuel-efficient lean-burn engines. We have used a multi-tiered approach to developing an elementary chemical mechanism benchmarked against experimental data: (1) Simulate a set of steady flow experiments, with storage effects minimized, to infer a tentative mechanism for chemistry on precious metal sites (completed). (2) Simulate a set of long cycle experiments to infer a mechanism for NOx and oxygen storage sites while simultaneously finalizing precious metal chemistry (completed). (3) Simulate a simplified sulfation/desulfation protocol to obtain a supplementary set of reactions involving sulfur on all three kinds of sites (nearly completed). (4) Investigate the potential role of reductants other than CO and H{sub 2}. While simulation of isothermal experiments is the preferred way to extract kinetic parameters, simulation of realistic storage/regeneration cycles requires that exotherms be considered. Our ultimate goal is to facilitate improved designs for LNT-based aftertreatment systems and to assist in the development of improved catalysts.

  10. Activity Enhancement of Pt/Ba/Al2O3 Mixed with Mn/Ba/Al2O3 for NOx Storage-reduction by Hydrogen

    Institute of Scientific and Technical Information of China (English)

    Jian Hua XIAO; Xue Hui LI; Sha DENG; Fu Rong WANG; Le Fu WANG

    2006-01-01

    Mn/Ba/Al2O3 catalyst for NO oxidation-storage and Pt/Ba/Al2O3 catalyst mixed with Mn/Ba/Al2O3 for NOx storage-reduction by hydrogen were investigated. The results showed that Mn/Ba/Al2O3 had large nitrogen oxides storage capacity (397.9 μmolg-1) under lean bum condition.When Pt/Ba/Al2O3 catalyst was mixed with Mn/Ba/Al2O3 in equal weight proportion, the NOx conversion increased between 250 ℃ and 500 ℃ under the dynamic lean-rich bum conditions, and the maximum NOx conversion increased from 95.4% to 98.2%. Mn/Ba/Al2O3 has promoted NOx storing in the lean stage and improved NOx reduction efficiency in the rich stage, these might result in higher NOx conversion over the low Pt loading content catalyst.

  11. Modeling Species Inhibition of NO Oxidation in Urea-SCR Catalysts for Diesel Engine NOx Control

    Energy Technology Data Exchange (ETDEWEB)

    Devarakonda, Maruthi N.; Tonkyn, Russell G.; Tran, Diana N.; Lee, Jong H.; Herling, Darrell R.

    2011-04-20

    Urea-selective catalytic reduction (SCR) catalysts are regarded as the leading NOx aftertreatment technology to meet the 2010 NOx emission standards for on-highway vehicles running on heavy-duty diesel engines. However, issues such as low NOx conversion at low temperature conditions still exist due to various factors, including incomplete urea thermolysis, inhibition of SCR reactions by hydrocarbons and H2O. We have observed a noticeable reduction in the standard SCR reaction efficiency at low temperature with increasing water content. We observed a similar effect when hydrocarbons are present in the stream. This effect is absent under fast SCR conditions where NO ~ NO2 in the feed gas. As a first step in understanding the effects of such inhibition on SCR reaction steps, kinetic models that predict the inhibition behavior of H2O and hydrocarbons on NO oxidation are presented in the paper. A one-dimensional SCR model was developed based on conservation of species equations and was coded as a C-language S-function and implemented in Matlab/Simulink environment. NO oxidation and NO2 dissociation kinetics were defined as a function of the respective adsorbate’s storage in the Fe-zeolite SCR catalyst. The corresponding kinetic models were then validated on temperature ramp tests that showed good match with the test data. Such inhibition models will improve the accuracy of model based control design for integrated DPF-SCR aftertreatment systems.

  12. NOx storage, desorption and reduction over Pd-K/MgAlO catalyst%Pd-K/MgAlO催化剂上的NOx 存储、脱附和还原过程

    Institute of Scientific and Technical Information of China (English)

    张业新; 王晓; 王力; 王仲鹏; 李倩; 张昭良

    2013-01-01

    The processes of NOx storage, desorption and reduction over Pd-K/MgAlO were investigated using temperature-programmed desorption ( TPD ) , temperature-programmed surface reduction ( TPSR ) and in situ IR. It was found that NOx storage on Pd-K/MgAlO was in the forms of ionic nitrites and ionic nitrates. In the presence of Pd, the nitrites were partically oxidized into nitrates with stronger acid strength, which were prone to be stored on the basic sites. As a result, the storage capacity of Pd-K/MgAlO reached 890. 4 μmol·g-1 from NOx-TPD results. Furthermore, the Pd-catalyzed disproportionation decomposition of nitrites was found in both NOx desorption and reduction with H2 , which proceeded via the spillover of the nitrites to the Pd sites. In this process, Pd was confirmed to promote NOx desorption at low temperatures and accelerate NOx reduction with H2 . These findings provide strong evidence for NOx ad-species spillover mechanism.%利用程序升温脱附( TPD)、程序升温表面反应( TPSR)和原位红外光谱( in situ IR)等技术研究了Pd-K/MgAlO催化剂上的NOx 存储、脱附和还原过程.结果表明,NOx 在Pd-K/MgAlO上主要以硝酸根和亚硝酸根的形式存储.在Pd的催化作用下,部分亚硝酸根被氧化为强酸性的硝酸根,变得更容易存储.由NOx-TPD计算得到Pd-K/MgAlO的NOx 存储容量高达890.4μmol·g-1.此外,在NOx 脱附及H2还原的实验中均发现了Pd催化的亚硝酸盐歧化分解反应,该反应通过亚硝酸盐溢流至Pd位实现.亚硝酸盐的溢流产生了两个作用:促进NOx 低温脱附及促进H2对存储NOx 的还原.此发现为NOx 存储物种的溢流机理提供了一个有力的证据.

  13. NO(x) decomposition, storage and reduction over novel mixed oxide catalysts derived from hydrotalcite-like compounds.

    Science.gov (United States)

    Yu, Jun Jie; Cheng, Jie; Ma, Chun Yan; Wang, Hai Lin; Li, Lan Dong; Hao, Zheng Ping; Xu, Zhi Ping

    2009-05-15

    Effective control and removal of nitrogen oxides (NO(x)) emission from vehicles exhausts under lean-burn condition is one of the most important targets in scientific research of environmental protection. A comprehensive introduction of NO(x) storage and reduction (NSR), the most promising lean-NO(x) control technology, is given including the sum-up of NSR materials, catalytic activity and related reaction mechanisms. Emphasis is put on the novel multifunctional NSR catalysts, derived from hydrotalcite-like compounds, with characteristic of simultaneous NO(x) strorage-decomposition-reduction. Finally, future research directions in the area of lean-NO(x) control based on mixed oxide catalysts derived from hydrotalcite-like materials is also proposed.

  14. Storage-Reduction of NOx over Combined Catalysts of Pt/Ba/Al2O3-Mn/Ba/Al2O3: Carbon Monoxide as Reductant

    Institute of Scientific and Technical Information of China (English)

    Sha Deng; Xuehui Li; Jianhua Xiao; Furong Wang; Lefu Wang

    2007-01-01

    Storage-reduction of NOx by carbon monoxide was investigated over combined catalysts of Mn/Ba/Al2O3-Pt/Ba/Al2O3. Combination of Mn/Ba/Al2O3 and Pt/Ba/Al2O3 catalysts in different ways showed excellent NOx storage-reduction performance and the content of Pt could be reduced by 50%.Not only the addition of 5Mn/15Ba/Al2O3 to 1Pt/15Ba/Al2O3 could improve its storage ability, but also enhance the NOx conversion consequently. NOx conversion over the combined catalysts (the combined catalysts Ⅰ and Ⅱ) was increased under dynamic lean-rich burn conditions, the maximum NOx conversion increased from 69.4% to respectively 78.8% and 75.7% over two combined catalysts.

  15. Effect of sulfate aerosol on tropospheric NOx and ozone budgets: Model simulations and TOPSE evidence

    Science.gov (United States)

    Tie, Xuexi; Emmons, Louisa; Horowitz, Larry; Brasseur, Guy; Ridley, Brian; Atlas, Elliot; Stround, Craig; Hess, Peter; Klonecki, Andrzej; Madronich, Sasha; Talbot, Robert; Dibb, Jack

    2003-02-01

    The distributions of NOx and O3 are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N2O5 on sulfate aerosols has on tropospheric NOx and O3 budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NOx concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; with this reaction, modeled NOx concentrations are close to the measured values. This comparison provides evidence that the hydrolysis of N2O5 on sulfate aerosol plays an important role in controlling the tropospheric NOx and O3 budgets. The calculated reduction of NOx attributed to this reaction is 80 to 90% in winter at high latitudes over North America. Because of the reduction of NOx, O3 concentrations are also decreased. The maximum O3 reduction occurs in spring although the maximum NOx reduction occurs in winter when photochemical O3 production is relatively low. The uncertainties related to uptake coefficient and aerosol loading in the model is analyzed. The analysis indicates that the changes in NOx due to these uncertainties are much smaller than the impact of hydrolysis of N2O5 on sulfate aerosol. The effect that hydrolysis of N2O5 on global NOx and O3 budgets are also assessed by the model. The results suggest that in the Northern Hemisphere, the average NOx budget decreases 50% due to this reaction in winter and 5% in summer. The average O3 budget is reduced by 8% in winter and 6% in summer. In the Southern Hemisphere (SH), the sulfate aerosol loading is significantly smaller than in the Northern Hemisphere. As a result, sulfate aerosol has little impact on NOx and O3 budgets of the Southern Hemisphere.

  16. Evaluating NOx emission inventories for regulatory air quality modeling using satellite and air quality model data

    Science.gov (United States)

    Kemball-Cook, Susan; Yarwood, Greg; Johnson, Jeremiah; Dornblaser, Bright; Estes, Mark

    2015-09-01

    The purpose of this study was to assess the accuracy of NOx emissions in the Texas Commission on Environmental Quality's (TCEQ) State Implementation Plan (SIP) modeling inventories of the southeastern U.S. We used retrieved satellite tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) together with NO2 columns from the Comprehensive Air Quality Model with Extensions (CAMx) to make top-down NOx emissions estimates using the mass balance method. Two different top-down NOx emissions estimates were developed using the KNMI DOMINO v2.0 and NASA SP2 retrievals of OMI NO2 columns. Differences in the top-down NOx emissions estimates made with these two operational products derived from the same OMI radiance data were sufficiently large that they could not be used to constrain the TCEQ NOx emissions in the southeast. The fact that the two available operational NO2 column retrievals give such different top-down NOx emissions results is important because these retrievals are increasingly being used to diagnose air quality problems and to inform efforts to solve them. These results reflect the fact that NO2 column retrievals are a blend of measurements and modeled data and should be used with caution in analyses that will inform policy development. This study illustrates both benefits and challenges of using satellite NO2 data for air quality management applications. Comparison with OMI NO2 columns pointed the way toward improvements in the CAMx simulation of the upper troposphere, but further refinement of both regional air quality models and the NO2 column retrievals is needed before the mass balance and other emission inversion methods can be used to successfully constrain NOx emission inventories used in U.S. regulatory modeling.

  17. Modeling of NOx Destruction Options for INEEL Sodium-Bearing Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Richard Arthur

    2001-09-01

    Off-gas NOx concentrations in the range of 1-5 mol% are expected as a result of the proposed vitrification of sodium-bearing waste at the Idaho National Engineering and Environmental Laboratory. An existing kinetic model for staged combustion (originally developed for NOx abatement from the calcination process) was updated for application to vitrification offgas. In addition, two new kinetic models were developed to assess the feasibility of using selective non-catalytic reduction (SNCR) or high-temperature alone for NOx abatement. Each of the models was developed using the Chemkin code. Results indicate that SNCR is a viable option, reducing NOx levels to below 1000 ppmv. In addition, SNCR may be capable of simultaneously reducing CO emissions to below 100 ppmv. Results for using high-temperature alone were not as promising, indicating that a minimum NOx concentration of 3950 ppmv is achievable at 3344°F.

  18. Application of the NOx Reaction Model for Development of Low-NOx Combustion Technology for Pulverized Coals by Using the Gas Phase Stoichiometric Ratio Index

    Directory of Open Access Journals (Sweden)

    Kenji Yamamoto

    2011-03-01

    Full Text Available We previously proposed the gas phase stoichiometric ratio (SRgas as an index to evaluate NOx concentration in fuel-rich flames. The SRgas index was defined as the amount of fuel required for stoichiometric combustion/amount of gasified fuel, where the amount of gasified fuel was the amount of fuel which had been released to the gas phase by pyrolysis, oxidation and gasification reactions. In the present study we found that SRgas was a good index to consider the gas phase reaction mechanism in fuel-rich pulverized coal flames. When SRgas < 1.0, NOx concentration was strongly influenced by the SRgas value. NOx concentration was also calculated by using a reaction model. The model was verified for various coals, particle diameters, reaction times, and initial oxygen concentrations. The most important reactions were gas phase NOx reduction reactions by hydrocarbons. The hydrocarbon concentration was estimated based on SRgas. We also investigated the ratio as an index to develop a new low-NOx combustion technology for pulverized coals. We examined the relation between local SRgas distribution in the fuel-rich region in the low-NOx flame and NOx emissions at the furnace exit, by varying burner structures. The relationship between local SRgas value and local NOx concentration was also examined. When a low-NOx type burner was used, the value of SRgas in the flame was readily decreased. When the local SRgas value was the same, it was difficult to influence the local NOx concentration by changing the burner structure. For staged combustion, the most important item was to design the burner structure and arrangement so that SRgas could be lowered as much as possible just before mixing with staged air.

  19. Sulfation and Desulfation Behavior of Pt-BaO/MgO-Al2O3 NOx Storage Reduction Catalyst.

    Science.gov (United States)

    Jeong, Soyeon; Kim, Do Heui

    2016-05-01

    The comparative study between Pt-BaO/Al2O3 and Pt-BaO/MgO-Al2O3 gives the information about the effect of MgO addition to Al2O3 support on the sulfation and desulfation behavior of Pt-BaO/MgO-Al2O3 NOx storage reduction catalyst. The sulfated two samples were analyzed by using element analysis (EA), X-ray diffraction (XRD), H2 temperature programmed reaction (H2 TPRX) and NOx uptake measurement. The amount of sulfur uptake on 2 wt% Pt-20 wt% BaO/Al2O3 and 2 wt% Pt-20 wt% BaO/MgO-Al2O3 are almost identical as 0.45 and 0.40 of S/Ba, respectively, which yields the drastic decrease in NOx uptake for both sulfated samples. However, after desulfa- tion with H2 at 600 degrees C, the residual sulfur amount on MgO-Al2O3 supported catalyst is three times larger than that on Al2O3 supported one, indicating that sulfur species formed on the former are more stable than those on the latter. It is also well corresponding to the H2 TPRX results where the main H2S peak from MgO-Al2O3 supported sample is observed at higher temperature than Al2O3 supported one, resulting in the lower NOx uptake activity of former sample than the latter one. Meanwhile, after desulfation of MgO-Al2O3 supported sample at 700 degrees C and 800 degrees C, the activity is recovered more significantly due to the removal of the large amount of sulfur while Al2O3 supported one decreases monotonically due to the sintering of Pt crystallite and the formation of BaAl2O4 phase. It is summarized that MgO-Al2O3 supported catalyst enhances the thermal stability of the catalyst, however, forms the stable sulfate species, which needs to be improved to develop the more sulfur resistant NSR catalyst system.

  20. Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling

    Directory of Open Access Journals (Sweden)

    W. Tang

    2014-09-01

    Full Text Available Uncertain photolysis rates and emission inventory impair the accuracy of state-level ozone (O3 regulatory modeling. Past studies have separately used satellite-observed clouds to correct the model-predicted photolysis rates, or satellite-constrained top-down NOx emissions to identify and reduce uncertainties in bottom-up NOx emissions. However, the joint application of multiple satellite-derived model inputs to improve O3 State Implementation Plan (SIP modeling has rarely been explored. In this study, Geostationary Operational Environmental Satellite (GOES observations of clouds are applied to derive the photolysis rates, replacing those used in Texas SIP modeling. This changes modeled O3 concentrations by up to 80 ppb and improves O3 simulations by reducing modeled normalized mean bias (NMB and normalized mean error (NME by up to 0.1. A sector-based discrete Kalman filter (DKF inversion approach is incorporated with the Comprehensive Air Quality Model with extensions (CAMx-Decoupled Direct Method (DDM model to adjust Texas NOx emissions using a high resolution Ozone Monitoring Instrument (OMI NO2 product. The discrepancy between OMI and CAMx NO2 vertical column densities (VCD is further reduced by increasing modeled NOx lifetime and adding an artificial amount of NO2 in the upper troposphere. The sector-based DKF inversion tends to scale down area and non-road NOx emissions by 50%, leading to a 2–5 ppb decrease in ground 8 h O3 predictions. Model performance in simulating ground NO2 and O3 are improved using inverted NOx emissions, with 0.25 and 0.04 reductions in NMBs and 0.13 and 0.04 reductions in NMEs, respectively. Using both GOES-derived photolysis rates and OMI-constrained NOx emissions together reduces modeled NMB and NME by 0.05 and increases the model correlation with ground measurement in O3 simulations and makes O3 more sensitive to NOx emissions in the O3 non-attainment areas.

  1. Experimental and modeling analysis of the NOxOUT process

    Energy Technology Data Exchange (ETDEWEB)

    Rota, R.; Antos, D.; Zanoelo, E.V.; Morbidelli, M. [Politecnico di Milano, Milano (Italy). Dipartimento di Chimica Fisica Applicata/CIIRCO

    2002-01-01

    The selective non-catalytic reduction of nitric oxide with urea has been investigated experimentally in a temperature range from 950 to 1450 K using a laboratory reactor that approximates well stirred conditions. From the experimental results it has been possible not only to deduce some generate trends of interest in the NOxOUT process, but also to validate a detailed kinetic mechanism. In particular, the experiments showed that the NOxOUT process is effective in a narrow temperature window. The effect of increasing the ratio of nitrogen in the reducing agent and in NO is to increase the efficiency of abatement, while that of increasing O{sub 2} concentration depends on the temperature considered. Moreover, the effect of increasing the CO/NO ratio up to one is not very pronounced. The detailed kinetic mechanism developed has been validated by comparison with several experimental findings, thus providing an effective tool for process simulation in a wide range of operating conditions.

  2. Fruit fly optimization algorithm based high efficiency and low NOx combustion modeling for a boiler

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhenxing∗; SUN Baomin; XIN Jing

    2014-01-01

    In order to control NOx emissions and enhance boiler efficiency in coal-fired boilers,the thermal operating data from an ultra-supercritical 1 000 MW unit boiler were analyzed.On the basis of the support vector regression machine (SVM),the fruit fly optimization algorithm (FOA)was applied to optimize the penalty parameter C,ker-nel parameter g and insensitive loss coefficient of the model.Then,the FOA-SVM model was established to predict the NOx emissions and boiler efficiency,and the performance of this model was compared with that of the GA-SVM model optimized by genetic algorithm (GA).The results show the FOA-SVM model has better prediction accuracy and generalization capability,of which the maximum average relative error of testing set lies in the NOx emissions model,which is only 3 .5 9%.The above models can predict the NOx emissions and boiler efficiency accurately,so they are very suitable for on-line modeling prediction,which provides a good model foundation for further optimiza-tion operation of large capacity boilers.

  3. Surface Tuning of La0.5Sr0.5CoO3 Perovskite Catalysts by Acetic Acid for NOx Storage and Reduction.

    Science.gov (United States)

    Peng, Yue; Si, Wenzhe; Luo, Jinming; Su, Wenkang; Chang, Huazhen; Li, Junhua; Hao, Jiming; Crittenden, John

    2016-06-21

    Selective dissolution of perovskite A site (A of ABO3 structure) was performed on the La1 - xSrxCoO3 catalysts for the NOx storage and reduction (NSR) reaction. The surface area of the catalysts were enhanced using dilute HNO3 impregnation to dissolve Sr. Inactive SrCO3 was removed effectively within 6 h, and the catalyst preserved the perovskite framework after 24 h of treatment. The tuned catalysts exhibited higher NSR performance (both NOx storage and NO-to-NO2 oxidation) under lean-burn and fuel-rich cycles at 250 °C. Large amounts of NOx adsorption were due to the increase of nitrate/nitrite species bonding to the A site and the growth of newly formed monodentate nitrate species. Nitrate species were stored stably on the partial exposed Sr(2+) cations. These exposed Sr(2+) cations played an important role on the NOx reduction by C3H6. High NO-to-NO2 oxidation ability was due to the generation of oxygen defects and Co(2+)-Co(3+) redox couples, which resulted from B-site exsolution induced by A-site dissolution. Hence, our method is facile to modify the surface structures of perovskite catalysts and provides a new strategy to obtain highly active catalysts for the NSR reaction.

  4. Modelling the spatial distribution of SO2 and NO(x) emissions in Ireland

    NARCIS (Netherlands)

    Kluizenaar, Y.de; Aherne, J.; Farrell, E.P.

    2001-01-01

    The spatial distributions of sulphur dioxide (SO2) and nitrogen oxides (NO(x)) emissions are essential inputs to models of atmospheric transport and deposition. Information of this type is required for international negotiations on emission reduction through the critical load approach. High-resoluti

  5. Electrochemical reduction of NOx

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund

    NO and NO2 (collectively referred to as NOx) are air pollutants, and the largest single contributor to NOx pollution is automotive exhaust. This study investigates electrochemical deNOx, a technology which aims to remove NOx from automotive diesel exhaust by electrochemical reduction of NOx to N2...... and O2. The focus in this study is on improving the activity and selectivity of solid oxide electrodes for electrochemical deNOx by addition of NOx storage compounds to the electrodes. Two different composite electrodes, La0.85Sr0.15MnO3-δ-Ce0.9Gd0.1O1.95 (LSM15-CGO10) and La0.85Sr0.15FeO3-δ-Ce0.9Gd0.1O......1.95 (LSF15-CGO10), have been investigated in combination with three different NOx storage compounds: BaO, K2O and MnOx. The main focus in the investigation has been on conversion measurements and electrochemical characterization, the latter by means of electrochemical impedance spectroscopy...

  6. CFD Study of NOx Emissions in a Model Commercial Aircraft Engine Combustor

    Institute of Scientific and Technical Information of China (English)

    ZHANG Man; FU Zhenbo; LIN Yuzhen; LI Jibao

    2012-01-01

    Air worthiness requirements of the aircraft engine emission bring new challenges to the combustor research and design.With the motivation to design high performance and clean combustor,computational fluid dynamics (CFD) is utilized as the powerful design approach.In this paper,Reynolds averaged Navier-Stokes (RANS) equations of reactive two-phase flow in an experimental low emission combustor is performed.The numerical approach uses an implicit compressible gas solver together with a Lagrangian liquid-phase tracking method and the extended coherent flamelet model for turbulence-combustion interaction.The NOx formation is modeled by the concept of post-processing,which resolves the NOx transport equation with the assumption of frozen temperature distribution.Both turbulence-combustion interaction model and NOx formation model are firstly evaluated by the comparison of experimental data published in open literature of a lean direct injection (LDI) combustor.The test rig studied in this paper is called low emission stirred swirl (LESS) combustor,which is a two-stage model combustor,fueled with liquid kerosene (RP-3) and designed by Beihang University (BUAA).The main stage of LESS combustor employs the principle of lean prevaporized and premixed (LPP) concept to reduce pollutant,and the pilot stage depends on a diffusion flame for flame stabilization.Detailed numerical results including species distribution,turbulence performance and burning performance are qualitatively and quantitatively evaluated.Numerical prediction of NOx emission shows a good agreement with test data at both idle condition and full power condition of LESS combustor.Preliminary results of the flame structure are shown in this paper.The flame stabilization mechanism and NOx reduction effort are also discussed with in-depth analysis.

  7. On the Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates Parameterization of Lightning NOx Production in CMAQ

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  8. SIMULATION OF NOx FORMATION IN TURBULENT SWIRLING COMBUSTION USING A USM TURBULENCE-CHEMISTRY MODEL

    Institute of Scientific and Technical Information of China (English)

    周力行; 乔丽; 张健

    2003-01-01

    A unified second-order moment (USM) turbulence-chemistry model for simulating NOx formation in turbulent combustion is proposed.All of correlations,including the correlation of the reaction-rate coefficient fluctuation with the concentration fluctuation,are closed by the transport equations in the same form.This model discards the approximation of series expansion of the exponential function or the approximation of using the product of several 1-D PDF's instead of a joint PDF.It is much simpler than other refined models,such as the PDF transport equation model and the conditional moment closure model.The proposed model is used to simulate methane-air swirling turbulent combustion and NOx formation.The prediction results are in good agreement with the experimental results.

  9. The influence of temperature on ozone production under varying NOx conditions - a modelling study

    Science.gov (United States)

    Coates, Jane; Mar, Kathleen A.; Ojha, Narendra; Butler, Tim M.

    2016-09-01

    Surface ozone is a secondary air pollutant produced during the atmospheric photochemical degradation of emitted volatile organic compounds (VOCs) in the presence of sunlight and nitrogen oxides (NOx). Temperature directly influences ozone production through speeding up the rates of chemical reactions and increasing the emissions of VOCs, such as isoprene, from vegetation. In this study, we used an idealised box model with different chemical mechanisms (Master Chemical Mechanism, MCMv3.2; Common Representative Intermediates, CRIv2; Model for OZone and Related Chemical Tracers, MOZART-4; Regional Acid Deposition Model, RADM2; Carbon Bond Mechanism, CB05) to examine the non-linear relationship between ozone, NOx and temperature, and we compared this to previous observational studies. Under high-NOx conditions, an increase in ozone from 20 to 40 °C of up to 20 ppbv was due to faster reaction rates, while increased isoprene emissions added up to a further 11 ppbv of ozone. The largest inter-mechanism differences were obtained at high temperatures and high-NOx emissions. CB05 and RADM2 simulated more NOx-sensitive chemistry than MCMv3.2, CRIv2 and MOZART-4, which could lead to different mitigation strategies being proposed depending on the chemical mechanism. The increased oxidation rate of emitted VOC with temperature controlled the rate of Ox production; the net influence of peroxy nitrates increased net Ox production per molecule of emitted VOC oxidised. The rate of increase in ozone mixing ratios with temperature from our box model simulations was about half the rate of increase in ozone with temperature observed over central Europe or simulated by a regional chemistry transport model. Modifying the box model set-up to approximate stagnant meteorological conditions increased the rate of increase of ozone with temperature as the accumulation of oxidants enhanced ozone production through the increased production of peroxy radicals from the secondary degradation of

  10. Transport of NOx in East Asia identified by satellite and in situ measurements and Lagrangian particle dispersion model simulations

    Science.gov (United States)

    Lee, H.-J.; Kim, S.-W.; Brioude, J.; Cooper, O. R.; Frost, G. J.; Kim, C.-H.; Park, R. J.; Trainer, M.; Woo, J.-H.

    2014-03-01

    Nitrogen dioxide (NO2) columns observed from space have been useful in detecting the increase of nitrogen oxides (NOx) emissions in East Asia, particularly China, coinciding with rapid economic growth during the past several decades. NO2 columns retrieved above a particular location reflect a combination of local NOx emissions and transported NOx from upwind sources. In this study, we demonstrate the transport of NOx emitted in East Asia using satellite and surface in situ measurements and Lagrangian particle dispersion model simulations. Enhanced satellite NO2 columns in the Yellow Sea (between China and South Korea) and the East Sea (between South Korea and Japan), and different seasonal variations of NO2 in China, North and South Korea, and Japan, suggest the importance of NOx transport in understanding the local NOx budget. Lagrangian transport model simulations with tracers of different chemical lifetimes identify source-receptor relationships that explain high NO2 over the oceans and springtime peaks in Korea and Japan, with China being the most likely source region. Our results have important implications for studies using satellite NO2 retrievals to derive NOx emissions at local scales in regions adjacent to large sources, such as in East Asia, Europe, and the Eastern U.S.

  11. Photochemical grid model implementation of VOC, NOx, and O3 source apportionment

    Directory of Open Access Journals (Sweden)

    R. H. F. Kwok

    2014-09-01

    Full Text Available For the purposes of developing optimal emissions control strategies, efficient approaches are needed to identify the major sources or groups of sources that contribute to elevated ozone (O3 concentrations. Source based apportionment techniques implemented in photochemical grid models track sources through the physical and chemical processes important to the formation and transport of air pollutants. Photochemical model source apportionment has been used to estimate impacts of specific sources, groups of sources (sectors, sources in specific geographic areas, and stratospheric and lateral boundary inflow on O3. The implementation and application of a source apportionment technique for O3 and its precursors, nitrogen oxides (NOx and volatile organic compounds (VOC, for the Community Multiscale Air Quality (CMAQ model are described here. The Integrated Source Apportionment Method (ISAM O3 approach is a hybrid of source apportionment and source sensitivity in that O3 production is attributed to precursor sources based on O3 formation regime (e.g., for a NOx-sensitive regime, O3 is apportioned to participating NOx emissions. This implementation is illustrated by tracking multiple emissions source sectors and lateral boundary inflow. NOx, VOC, and O3 attribution to tracked sectors in the application are consistent with spatial and temporal patterns of precursor emissions. The O3 ISAM implementation is further evaluated through comparisons of apportioned ambient concentrations and deposition amounts with those derived from brute force zero-out scenarios, with correlation coefficients ranging between 0.58 and 0.99 depending on specific combination of target species and tracked precursor emissions. Low correlation coefficients occur for chemical regimes that have strong non-linearity in O3 sensitivity, which demonstrates different functionalities between source apportionment and zero-out approaches, depending on whether sources of interest are either to

  12. INTEGRATED HYDROGEN STORAGE SYSTEM MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, B

    2007-11-16

    Hydrogen storage is recognized as a key technical hurdle that must be overcome for the realization of hydrogen powered vehicles. Metal hydrides and their doped variants have shown great promise as a storage material and significant advances have been made with this technology. In any practical storage system the rate of H2 uptake will be governed by all processes that affect the rate of mass transport through the bed and into the particles. These coupled processes include heat and mass transfer as well as chemical kinetics and equilibrium. However, with few exceptions, studies of metal hydrides have focused primarily on fundamental properties associated with hydrogen storage capacity and kinetics. A full understanding of the complex interplay of physical processes that occur during the charging and discharging of a practical storage system requires models that integrate the salient phenomena. For example, in the case of sodium alanate, the size of NaAlH4 crystals is on the order of 300nm and the size of polycrystalline particles may be approximately 10 times larger ({approx}3,000nm). For the bed volume to be as small as possible, it is necessary to densely pack the hydride particles. Even so, in packed beds composed of NaAlH{sub 4} particles alone, it has been observed that the void fraction is still approximately 50-60%. Because of the large void fraction and particle to particle thermal contact resistance, the thermal conductivity of the hydride is very low, on the order of 0.2 W/m-{sup o}C, Gross, Majzoub, Thomas and Sandrock [2002]. The chemical reaction for hydrogen loading is exothermic. Based on the data in Gross [2003], on the order of 10{sup 8}J of heat of is released for the uptake of 5 kg of H{sub 2}2 and complete conversion of NaH to NaAlH{sub 4}. Since the hydride reaction transitions from hydrogen loading to discharge at elevated temperatures, it is essential to control the temperature of the bed. However, the low thermal conductivity of the hydride

  13. Parameter study of a model for NOx emissions from PFBC

    DEFF Research Database (Denmark)

    Jensen, Anker Degn; Johnsson, Jan Erik

    1996-01-01

    Simulations with a mathematical model of a pressurized bubbling fluidized bed combustor (PFBC) combined with a kinetic model for NO formation and reduction are presented and discussed. The kinetic model for NO formation and reduction considers NO and NH3 as the fixed nitrogen species, and includes...... homogeneous reactions and heterogeneous reactions catalyzed by bed material and char. Simulations of the influence of operating conditions: air staging, load, temperature, fuel particle size, bed particle size and bed inventory on the NO emission is presented and the trends are compared to experimental data...

  14. A two-dimensional volatility basis set – Part 3: Prognostic modeling and NOx dependence

    Directory of Open Access Journals (Sweden)

    W. K. Chuang

    2015-06-01

    Full Text Available When NOx is introduced to organic emissions, aerosol production is sometimes, but not always, reduced. Under certain conditions, these interactions will instead increase aerosol concentrations. We expanded the two-dimensional volatility basis set (2-D-VBS to include the effects of NOx on aerosol formation. This includes the formation of organonitrates, where the addition of a nitrate group contributes to a decrease of 2.5 orders of magnitude in volatility. With this refinement, we model outputs from experimental results, such as the atomic N : C ratio, organonitrate mass, and nitrate fragments in AMS measurements. We also discuss the mathematical methods underlying the implementation of the 2-D-VBS and provide the complete code in the Supplemental material. A developer version is available on Bitbucket, an online community repository.

  15. Inversion of CO and NOx emissions using the adjoint of the IMAGES model

    Directory of Open Access Journals (Sweden)

    T. Stavrakou

    2004-12-01

    Full Text Available We use ground-based observations of CO mixing ratios and vertical column abundances together with tropospheric NO2 columns from the GOME satellite instrument as constraints for improving the global annual emission estimates of CO and NOx for the year 1997. The agreement between concentrations calculated by the global 3-dimensional CTM IMAGES and the observations is optimized using the adjoint modelling technique, which allows to invert for CO and NOx fluxes simultaneously, taking their chemical interactions into account. Our analysis quantifies a total of 39 flux parameters, comprising anthropogenic and biomass burning sources over large continental regions, soil and lightning emissions of NOx, biogenic emissions of CO and non-methane hydrocarbons, as well as the deposition velocities of both CO and NOx. Comparison between observed, prior and optimized CO mixing ratios at NOAA/CMDL sites shows that the inversion performs well at the northern mid- and high latitudes, and that it is less efficient in the Southern Hemisphere, as expected due to the scarsity of measurements over this part of the globe. The inversion, moreover, brings the model much closer to the measured NO2 columns over all regions. Sensitivity tests show that anthropogenic sources exhibit weak sensitivity to changes of the a priori errors associated to the bottom-up inventory, whereas biomass burning sources are subject to a strong variability. Our best estimate for the 1997 global top-down CO source amounts to 2760 Tg CO. Anthropogenic emissions increase by 28%, in agreement with previous inverse modelling studies, suggesting that the present bottom-up inventories underestimate the anthropogenic CO emissions in the Northern Hemisphere. The magnitude of the optimized NOx global source decreases by 14% with respect to the prior, and amounts to 42.1 Tg N, out of which 22.8 Tg N are due to anthropogenic sources. The NOx emissions increase over Tropical regions, whereas they

  16. Mathematical modeling of an in-line low-NOx calciner

    DEFF Research Database (Denmark)

    Iliuta, Ion; Dam-Johansen, Kim; Jensen, Lars Skaarup

    2002-01-01

    is very important. A heterogeneous, dynamic mathematical model for an in-line low-NOx calciner based on non-isothermal diffusion reaction models for char combustion and limestone calcination has been developed. The importance of the rate at which preheated combustion air was mixed into the main flow...... transport limitation is significant for the endothermic limestone calcination. The rate at which preheated combustion air is mixed into the main flow directly influences the coal combustion rate, and thereby through the rate of heat release from combustion, it also influences the calcination rate...

  17. Modeling of in-line low-NOx calciners - a parametric study

    DEFF Research Database (Denmark)

    Iliuta, Ion; Dam-Johansen, Kim; Jensen, Anker;

    2002-01-01

    Simulations with a heterogeneous model of an in-line low-NOx calciner, based on non-isothermal diffusion-reaction models for char combustion and limestone calcination combined with a kinetic model for NO formation and reduction, are reported. The analysis shows that the most important hydrodynamic...... parameter is the mixing rate of preheated combustion air into the sub-stoichiometric suspension leaving the reducing zone and the most important combustion parameter is the char reactivity. Also, the calcination rate modifies very much the temperature in the calciner, char and limestone conversion...... and NO emission. Carbon monoxide is a key component for the reduction of NO and reliable data for the kinetics of NO reduction by CO over CaO are very important for the prediction of the NO emission. The internal surface area of char and limestone particles influences the combustion and calcination rates...

  18. Altered p53 and NOX1 activity cause bioenergetic defects in a SCA7 polyglutamine disease model.

    Science.gov (United States)

    Ajayi, Abiodun; Yu, Xin; Wahlo-Svedin, Carolina; Tsirigotaki, Galateia; Karlström, Victor; Ström, Anna-Lena

    2015-01-01

    Spinocerebellar ataxia type 7 (SCA7) is one of the nine neurodegenerative disorders caused by expanded polyglutamine (polyQ) domains. Common pathogenic mechanisms, including bioenergetics defects, have been suggested for these so called polyQ diseases. However, the exact molecular mechanism(s) behind the metabolic dysfunction is still unclear. In this study we identified a previously unreported mechanism, involving disruption of p53 and NADPH oxidase 1 (NOX1) activity, by which the expanded SCA7 disease protein ATXN7 causes metabolic dysregulation. The NOX1 protein is known to promote glycolytic activity, whereas the transcription factor p53 inhibits this process and instead promotes mitochondrial respiration. In a stable inducible PC12 model of SCA7, p53 and mutant ATXN7 co-aggregated and the transcriptional activity of p53 was reduced, resulting in a 50% decrease of key p53 target proteins, like AIF and TIGAR. In contrast, the expression of NOX1 was increased approximately 2 times in SCA7 cells. Together these alterations resulted in a decreased respiratory capacity, an increased reliance on glycolysis for energy production and a subsequent 20% reduction of ATP in SCA7 cells. Restoring p53 function, or suppressing NOX1 activity, both reversed the metabolic dysfunction and ameliorated mutant ATXN7 toxicity. These results hence not only enhance the understanding of the mechanisms causing metabolic dysfunction in SCA7 disease, but also identify NOX1 as a novel potential therapeutic target in SCA7 and possibly other polyQ diseases.

  19. Modeling and Multi-Objective Optimization of NOx Conversion Efficiency and NH3 Slip for a Diesel Engine

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2016-05-01

    Full Text Available The objective of the study is to present the modeling and multi-objective optimization of NOx conversion efficiency and NH3 slip in the Selective Catalytic Reduction (SCR catalytic converter for a diesel engine. A novel ensemble method based on a support vector machine (SVM and genetic algorithm (GA is proposed to establish the models for the prediction of upstream and downstream NOx emissions and NH3 slip. The data for modeling were collected from a steady-state diesel engine bench calibration test. After obtaining the two conflicting objective functions concerned in this study, the non-dominated sorting genetic algorithm (NSGA-II was implemented to solve the multi-objective optimization problem of maximizing NOx conversion efficiency while minimizing NH3 slip under certain operating points. The optimized SVM models showed great accuracy for the estimation of actual outputs with the Root Mean Squared Error (RMSE of upstream and downstream NOx emissions and NH3 slip being 44.01 × 10−6, 21.87 × 10−6 and 2.22 × 10−6, respectively. The multi-objective optimization and subsequent decisions for optimal performance have also been presented.

  20. Production of lightning NOx and its vertical distribution calculated from three-dimensional cloud-scale chemical transport model simulations

    KAUST Repository

    Ott, Lesley E.

    2010-02-18

    A three-dimensional (3-D) cloud-scale chemical transport model that includes a parameterized source of lightning NOx on the basis of observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms observed during four field projects. Production per intracloud (PIC) and cloud-to-ground (PCG) flash is estimated by assuming various values of PIC and PCG for each storm and determining which production scenario yields NOx mixing ratios that compare most favorably with in-cloud aircraft observations. We obtain a mean PCG value of 500 moles NO (7 kg N) per flash. The results of this analysis also suggest that on average, PIC may be nearly equal to PCG, which is contrary to the common assumption that intracloud flashes are significantly less productive of NO than are cloud-to-ground flashes. This study also presents vertical profiles of the mass of lightning NOx after convection based on 3-D cloud-scale model simulations. The results suggest that following convection, a large percentage of lightning NOx remains in the middle and upper troposphere where it originated, while only a small percentage is found near the surface. The results of this work differ from profiles calculated from 2-D cloud-scale model simulations with a simpler lightning parameterization that were peaked near the surface and in the upper troposphere (referred to as a “C-shaped” profile). The new model results (a backward C-shaped profile) suggest that chemical transport models that assume a C-shaped vertical profile of lightning NOx mass may place too much mass near the surface and too little in the middle troposphere.

  1. Lightning NOx Production in CMAQ: Part II - Parameterization Based on Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  2. Lightning NOx Production in CMAQ: Part II - Parameterization Based on Relationship between Observed NLDN Lightning Strikes and Modeled Convective Precipitation Rates

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  3. MODELLING AND MEASUREMENT OF NOx CONCENTRATION IN PLUME FROM AIRCRAFT ENGINE UNDER OPERATION CONDITIONS AT THE AERODROME AREA

    Directory of Open Access Journals (Sweden)

    Oleksandr Zaporozhets

    2016-06-01

    Full Text Available Purpose: Airport air pollution is growing concern because of the air traffic expansion over the years (at annual rate of 5 %, rising tension of airports and growing cities expansion close each other (for such Ukrainian airports, as Zhulyany, Boryspol, Lviv, Odesa and Zaporizhzhia and accordingly growing public concern with air quality around the airport. Analysis of inventory emission results at major European and Ukrainian airports highlighted, that an aircraft is the dominant source of air pollution in most cases under consideration. For accurate assessment of aircraft emission contribution to total airport pollution and development of successful mitigation strategies, it is necessary to combine the modeling and measurement methods. Methods: Measurement of NOx concentration in the jet/plume from aircraft engine was implemented by chemiluminescence method under real operating conditions (taxi, landing, accelerating on the runway and take-off at International Boryspol airport (IBA. Modeling of NOx concentration was done by complex model PolEmiCa, which takes into account the transport and dilution of air contaminates by exhaust gases jet and the wing trailing vortexes.Results: The results of the measured NOx concentration in plume from aircraft engine for take-off conditions at IBA were used for improvement and validation of the complex model PolEmiCa. The comparison of measured and modeled instantaneous concentration of NOx was sufficiently improved by taking into account the impact of wing trailing vortices on the parameters of the jet (buoyancy height, horizontal and vertical deviation and on concentration distribution in plume. Discussion: Combined approach of modeling and measurement methods provides more accurate representation of aircraft emission contribution to total air pollution in airport area. Modeling side provides scientific grounding for organization of instrumental monitoring of aircraft engine emissions, particularly, scheme

  4. Mathematical Storage-Battery Models

    Science.gov (United States)

    Chapman, C. P.; Aston, M.

    1985-01-01

    Empirical formula represents performance of electrical storage batteries. Formula covers many battery types and includes numerous coefficients adjusted to fit peculiarities of each type. Battery and load parameters taken into account include power density in battery, discharge time, and electrolyte temperature. Applications include electric-vehicle "fuel" gages and powerline load leveling.

  5. Summertime weekly cycles of observed and modeled NOx and O3 concentrations as a function of land use type and ozone production sensitivity over the Continental United States

    Directory of Open Access Journals (Sweden)

    P. Lee

    2012-01-01

    Full Text Available Simulation results from the Community Multiscale Air Quality (CMAQ model version 4.7.1 over the Conterminous United States (CONUS for August 2009 are analyzed to evaluate how satellite-derived O3 sensitivity regimes capture weekly cycles of the U.S. EPA's Air Quality System (AQS observed ground-level concentrations of ozone (O3. AQS stations are classified according to a geographically-based land use designation or an O3-NOx-VOC chemical sensitivity regime. Land use designations are derived from the Advanced Very High Resolution Radiometer (AVHRR global land cover characteristic data representing three features: urban regions, forest regions, and other regions. The O3 chemical regimes (NOx-saturated, mixed, and NOx-sensitive are inferred from low to high values of photochemical indicators based on the ratio of the HCHO to NO2 column density from the Global Ozone Monitoring Experiment 2 (GOME-2 and CMAQ. Both AQS-observed weekly cycles of NOx at measurement sites over AVHRR geographical regions and GOME-2 sensitivity regimes show high NOx on weekdays and low NOx on weekends. However, the AQS-observed O3 weekly cycle at sites over the GOME-2 NOx-saturated regime is noticeably different from that over the AVHRR urban region. Whereas the high weekend O3 anomaly is clearly shown at sites over the GOME-2 NOx-saturated regime in both AQS and CMAQ, the weekend effect is not captured at other sites over the AVHRR urban region. In addition, the weekend effect from AQS is more clearly discernible at sites above the GOME-2 NOx-saturated regime than at other sites above the CMAQ NOx-saturated regime. This study suggests that chemical classifications of GOME-2 chemical regime stations produces better results for weekly O3 cycles than either the CMAQ chemical or AVHRR geographical classifications.

  6. NOx dispersion modelling around roundabout in a small city, example from Hungary

    Science.gov (United States)

    Farkas, Orsolya; Rákai, Anikó; Czáder, Károly; Török, Ákos

    2013-04-01

    The present paper focuses on the modelling of pollutant distribution and dispersion in an urban region that is located in a moderately industrialized town of Hungary, Székesfehérvár, with a population of 100,000. The study area is located close to the city centre, with different housing styles and different building elevations. High-rise buildings with 10 floors to small houses with gardens are found in the modelled area. The roundabout has 5 access roads; three major ones and two minor ones with different geometries and traffic load. The traffic load of the roads was defined by traffic count, while for the meteorological characteristics wind-statistics were created. Additional input parameters were the ground plan and the elevation of buildings. To simulate the airflow and the dispersion of pollutants a Computational Fluid Dynamics code called MISKAM was used. The background concentration was taken from the dataset of a nearby air quality monitoring station. According to vehicle counting the 5 roads of the roundabout have very different loads from 12 vehicles to more than 412 vehicles/hour. Three different grid systems were applied ranging from half million to 5 million cells. The difference in the results related to grid density was also evaluated. Wind speed distribution, wind turbulence and building wake flow patterns were identified by using the model. With the help of the simulation the NOx flow and dispersion of pollutants around the roundabout can be estimated and the critical locations with higher pollution concentration are presented. The results of the modelling can be more generalized and used in the design of the layout, development, traffic-control and environmental aspects of roundabouts located in small urban areas.

  7. Modelling study of NOx removal in oil-fired waste off-gases under electron beam irradiation

    Science.gov (United States)

    Zwolińska, Ewa; Sun, Yongxia; Chmielewski, A. G.; Nichipor, H.; Bulka, S.

    2015-08-01

    Computer simulations for high concentration of NOx removal from oil-fired waste off-gases under electron beam irradiation were carried out by using the Computer code "Kinetic" and GEAR method. 293 reactions involving 64 species were used for the modelling calculations. The composition of simulated oil-fired off-gas was the same as the experimental conditions. The calculations were made for following system: (75.78% N2+11.5% CO2+8.62% H2O+4.1% O2), NOx concentration varies from 200 ppm to 1500 ppm. Calculation results qualitatively agree with the experimental results. Furthermore the influence of temperature, SO2 concentration and ammonia addition is discussed.

  8. Capacity Expansion Modeling for Storage Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hale, Elaine; Stoll, Brady; Mai, Trieu

    2017-04-03

    The Resource Planning Model (RPM) is a capacity expansion model designed for regional power systems and high levels of renewable generation. Recent extensions capture value-stacking for storage technologies, including batteries and concentrating solar power with storage. After estimating per-unit capacity value and curtailment reduction potential, RPM co-optimizes investment decisions and reduced-form dispatch, accounting for planning reserves; energy value, including arbitrage and curtailment reduction; and three types of operating reserves. Multiple technology cost scenarios are analyzed to determine level of deployment in the Western Interconnection under various conditions.

  9. NOx Change over China and Its Influences

    Institute of Scientific and Technical Information of China (English)

    LIU Yu(刘煜); I. S. A. ISAKSEN; J. K. SUNDET; HE Jinhai(何金海); YAN Peng(颜鹏)

    2004-01-01

    A 3-D chemical transport model (OSLO CTM2) is used to investigate the impact of the increase of NOx emission over China.The model is capable to reproduce basically the seasonal variation of surface NOx and ozone over eastern China.NOx emission data and observations reveal that NOx over easternChina increases quite quickly with the economic development of China.Model results indicate that NOxconcentration over eastern China increasingly rises with the increase of NOx emission over China,and accelerates to increase in winter.When the NOx emission increases from 1995 to its double,the ratio of NO2/NOx abruptly drops in winter over northern China.Ozone at the surface decreases in winter with the continual enhancement of the NOx level over eastern China,but increases over southern China in summertime.It is noticeable that peak ozone over northern China increases in summer although mean ozone changes little.In summer,ozone increases in the free troposphere dominantly below 500 hPa.Moreover,the increases of total ozone over eastern China are proportional to the increases of NOx emission.In a word,the model results suggest that the relationship between NOx and ozone at the surface would change with NOx increase.

  10. 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.

  11. Modeling of NOx and Soot Formation in Diesel Combustion Modélisation de la formation des NOx et de la suie en combustion diesel

    Directory of Open Access Journals (Sweden)

    Dederichs A. S.

    2006-12-01

    Full Text Available An approach to model the formation and oxidation or reduction of soot and NO in turbulent diffusion flames is presented. The model is based on the flamelet library approach and extended to account for radiative heat losses in the flame. Due to the rather slow processes leading to soot and NO a modified flamelet library approach is used. Instead of taking the mass fractions directly from flamelet libraries the different source terms for soot and NO formation are calculated and a transport equation for the mean mass fractions is solved in the CFD calculation. The source terms are obtained from laminar counterflow-flame calculations using a detailed chemistry model for the gas phase species and the formation and oxidation of soot. Transport equations for the mean mixture fraction and the mixture fraction variance are solved and the chemical source term is closed by presuming a beta-function like distribution of mixture fraction and a log-normal distribution of the scalar dissipation rate. The model was first tested in laminar and turbulent jet flames. By applying a reduction strategy for the flamelet libraries of the source terms it was made applicable to the simulation of soot formation in a Diesel spray taking different oxidizer temperatures and pressures into account. Additionally, different formulations of the flamelet equations have been tested and their accuracy has been evaluated by comparing them to turbulent flame experiments. Cet article présente une approche de modélisation de la formation et de l'oxydation ou de la réduction des suies et des NOx dans les flammes de diffusion turbulente. Le modèle repose sur l'étude des données d'une bibliographie de flamelets , et intègre la prise en compte des pertes radiatives de chaleur dans la flamme. Comme les processus de formation des suies et NO sont relativement lents, une nouvelle approche modifiée est proposée. Au lieu d'extraire les concentrations de suies et NO directement de la

  12. Influence of enhanced Asian NOx emissions on ozone in the upper troposphere and lower stratosphere in chemistry-climate model simulations

    Science.gov (United States)

    Roy, Chaitri; Fadnavis, Suvarna; Müller, Rolf; Ayantika, D. C.; Ploeger, Felix; Rap, Alexandru

    2017-01-01

    The Asian summer monsoon (ASM) anticyclone is the most pronounced circulation pattern in the upper troposphere and lower stratosphere (UTLS) during northern hemispheric summer. ASM convection plays an important role in efficient vertical transport from the surface to the upper-level anticyclone. In this paper we investigate the potential impact of enhanced anthropogenic nitrogen oxide (NOx) emissions on the distribution of ozone in the UTLS using the fully coupled aerosol-chemistry-climate model, ECHAM5-HAMMOZ. Ozone in the UTLS is influenced both by the convective uplift of ozone precursors and by the uplift of enhanced-NOx-induced tropospheric ozone anomalies. We performed anthropogenic NOx emission sensitivity experiments over India and China. In these simulations, covering the years 2000-2010, anthropogenic NOx emissions have been increased by 38 % over India and by 73 % over China with respect to the emission base year 2000. These emission increases are comparable to the observed linear trends of 3.8 % per year over India and 7.3 % per year over China during the period 2000 to 2010. Enhanced NOx emissions over India by 38 % and China by 73 % increase the ozone radiative forcing in the ASM anticyclone (15-40° N, 60-120° E) by 16.3 and 78.5 mW m-2 respectively. These elevated NOx emissions produce significant warming over the Tibetan Plateau and increase precipitation over India due to a strengthening of the monsoon Hadley circulation. However, increase in NOx emissions over India by 73 % (similar to the observed increase over China) results in large ozone production over the Indo-Gangetic Plain and Tibetan Plateau. The higher ozone concentrations, in turn, induce a reversed monsoon Hadley circulation and negative precipitation anomalies over India. The associated subsidence suppresses vertical transport of NOx and ozone into the ASM anticyclone.

  13. Opportunity NOx

    Energy Technology Data Exchange (ETDEWEB)

    Karrs, M.; Albano, J.V. [ABB Lummus Global Inc., (United States)

    2002-03-01

    Legislation on the emission of oxides of nitrogen (NO{sub x}) from stationery fired sources is becoming ever more stringent. The only proven technology for reducing NOx to below 10 ppm in flue gas is selective catalytic reduction (SCR) at temperatures of 400 - 700 Fahrenheit. But, since modern refinery and petrochemical heater stack temperatures are below this range, retrofitting a catalytic reducer to an existing heater was difficult and expensive. ABB Lummus Heat Transfer took up this problem and have developed a low impact solution for SCR retrofits. The system developed is compact and the modular design facilitates fabrication almost anywhere in the world. The modular design keeps downtime to a minimum. The investment costs are site specific but the system has marked advantages over the retrofitting of low NO{sub x} burners.

  14. DCMDSM: a DICOM decomposed storage model.

    Science.gov (United States)

    Savaris, Alexandre; Härder, Theo; von Wangenheim, Aldo

    2014-01-01

    To design, build, and evaluate a storage model able to manage heterogeneous digital imaging and communications in medicine (DICOM) images. The model must be simple, but flexible enough to accommodate variable content without structural modifications; must be effective on answering query/retrieval operations according to the DICOM standard; and must provide performance gains on querying/retrieving content to justify its adoption by image-related projects. The proposal adapts the original decomposed storage model, incorporating structural and organizational characteristics present in DICOM image files. Tag values are stored according to their data types/domains, in a schema built on top of a standard relational database management system (RDBMS). Evaluation includes storing heterogeneous DICOM images, querying metadata using a variable number of predicates, and retrieving full-content images for different hierarchical levels. When compared to a well established DICOM image archive, the proposal is 0.6-7.2 times slower in storing content; however, in querying individual tags, it is about 48.0% faster. In querying groups of tags, DICOM decomposed storage model (DCMDSM) is outperformed in scenarios with a large number of tags and low selectivity (being 66.5% slower); however, when the number of tags is balanced with better selectivity predicates, the performance gains are up to 79.1%. In executing full-content retrieval, in turn, the proposal is about 48.3% faster. DCMDSM is a model built for the storage of heterogeneous DICOM content, based on a straightforward database design. The results obtained through its evaluation attest its suitability as a storage layer for projects where DICOM images are stored once, and queried/retrieved whenever necessary. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  15. Impact of Aircraft NOx Emission on NOx and Ozone over China

    Institute of Scientific and Technical Information of China (English)

    刘煜; I.S.A.ISAKSEN; J.K.SUNDET; 周秀骥; 马建中

    2003-01-01

    A three-dimensional global chemistry transport model (OSLO CTM2) is used to investigate the impact of subsonic aircraft NOx emission on NOz and ozone over China in terms of a year 2000 scenario of subsonic aircraft NOx emission. The results show that subsonic aircraft NOx emission significantly affects northern China, which makes NOx at 250 hPa increase by about 50 pptv with the highest percentage of 60% in January, and leading to an ozone increase of 8 ppbv with 5% relative change in April. The NOx increase is mainly attributed to the transport process, but ozone increase is produced by the chemical process. The NOx increases by less than 10 pptv by virtue of subsonic aircraft NOx emission over China,and ozone changes less than 0.4 ppbv. When subsonic aircraft NOx emission over China is doubled, its influence is still relatively small.

  16. The influence of cloud chemistry on HOx and NOx in the Marine Boundary Layer: a 1-D modelling study

    Directory of Open Access Journals (Sweden)

    F. J. Dentener

    2001-10-01

    Full Text Available A 1-D marine stratocumulus cloud model has been supplemented with a comprehensive and up-to-date aqueous phase chemical mechanism for the purpose of assessing the impact that the presence of clouds and aerosols has on gas phase HOx, NOx and O3 budgets in the marine boundary layer. The simulations presented here indicate that cloud may act as a heterogeneous source of HONOg via the conversion of HNO4(g at moderate pH (~4.5. The photolysis of nitrate (NO3- has also been found to contribute to this simulated increase in HONOg by ~5% and also acts as a minor source of NO2(g. The effect of introducing deliquescent aerosol on the simulated increase of HONOg is negligible. The most important consequences of this elevation in HONOg are that, in the presence of cloud, gas phase concentrations of NOx species increase by a factor of 2, which minimises the simulated decrease in O3(g, and results in a regeneration of OHg. This partly compensates for the removal of OHg by direct phase transfer into the cloud and has important implications regarding the oxidising capacity of the marine boundary layer. The findings presented here also suggest that previous modelling studies, which neglect the heterogeneous HNO4(g reaction cycle, may have over-estimated the role of clouds as a sink for OHg and O3(gin unpolluted oceanic regions, by ~10% and ~2%, respectively.

  17. Modelling NOX concentrations through CFD-RANS in an urban hot-spot using high resolution traffic emissions and meteorology from a mesoscale model

    Science.gov (United States)

    Sanchez, Beatriz; Santiago, Jose Luis; Martilli, Alberto; Martin, Fernando; Borge, Rafael; Quaassdorff, Christina; de la Paz, David

    2017-08-01

    Air quality management requires more detailed studies about air pollution at urban and local scale over long periods of time. This work focuses on obtaining the spatial distribution of NOx concentration averaged over several days in a heavily trafficked urban area in Madrid (Spain) using a computational fluid dynamics (CFD) model. A methodology based on weighted average of CFD simulations is applied computing the time evolution of NOx dispersion as a sequence of steady-state scenarios taking into account the actual atmospheric conditions. The inputs of emissions are estimated from the traffic emission model and the meteorological information used is derived from a mesoscale model. Finally, the computed concentration map correlates well with 72 passive samplers deployed in the research area. This work reveals the potential of using urban mesoscale simulations together with detailed traffic emissions so as to provide accurate maps of pollutant concentration at microscale using CFD simulations.

  18. Evaluating NOx Emissions Using Satellite Observations

    Science.gov (United States)

    Frost, G. J.; Kim, S.; Brioude, J.; McKeen, S. A.; Trainer, M.; Heckel, A.; Hilboll, A.; Richter, A.; Burrows, J. P.; Gleason, J. F.; Boersma, K. F.; Hsie, E.; Lee, S.; Angevine, W. M.; Granier, C.; Peischl, J.; Ryerson, T. B.; Fehsenfeld, F. C.

    2012-12-01

    Atmospheric NO2 columns retrieved from satellites can provide a useful top-down assessment of bottom-up NOx emissions inventories. We present three case studies of an approach to evaluate NOx emissions at a sector level by comparing satellite retrievals to regional chemical-transport model calculations of NO2 columns. In the first example, the atmospheric impact of implementing NOx controls at eastern US power plants is demonstrated. In the second study, we use NOx monitors at western US power plants to calibrate our satellite-model comparisons. We then apply our approach to evaluate bottom-up estimates of NOx emissions from western US cities. In the third example, we validate our satellite-model approach using in-situ aircraft measurements and assess NOx emissions from power plants, cities, industrial facilities, and ports in eastern Texas. We conclude with some general insights on the usefulness of this approach and suggestions for future areas of research.

  19. Validation of a zero-dimensional model for prediction of NOx and engine performance for electronically controlled marine two-stroke diesel engines

    DEFF Research Database (Denmark)

    Scappin, Fabio; Stefansson, Sigurður H.; Haglind, Fredrik

    2012-01-01

    combustion model using ideal gas law equations over a complete crank cycle. The combustion process is divided into intervals, and the product composition and flame temperature are calculated in each interval. The NOx emissions are predicted using the extended Zeldovich mechanism. The model is validated using...

  20. Modelling simulations of NOx and HOx in the middle and upper atmosphere using a 3D Whole Atmosphere Community Climate Model with D region ion-neutral chemistry

    Science.gov (United States)

    Feng, W.; Plane, J. M. C.; Kovacs, T.; Chipperfield, M.; Marsh, D. R.; Smith, A. K.; Verronen, P. T.; Newnham, D.; Clilverd, M. A.

    2016-12-01

    In the middle and upper atmosphere, the distributions of odd nitrogen NOx (NO, NO2) and odd hydrogen HOx (OH, HO2) are controlled by transport processes and chemistry. Energetic particle precipitation (of protons and electrons) produces NOx and HOx through ion-molecule chemistry, and this can play an important role in the chemistry of the mesosphere. There is also increasing evidence that the descent of NOx can destroy stratospheric O3 at high latitudes. Therefore, it is crucial to understand the importance of their production/loss rates, horizontal/vertical transport to advance our knowledge in the evolution of NOx and HOx as well as other related chemical species (e.g. HNO3, ClNO3, O and O3). Recently, we have developed a new coupled ion-neutral chemical model for the ionospheric D region (altitudes 50 - 90 km) based on the Sodankylä Ion and neutral Chemistry (SIC) model and 3D Whole Atmosphere Community Climate Model (WACCM), termed WACCM-SIC (Kovacs et al., 2016). An extra 306 ion-neutral and ion-recombination reactions of neutral species, positive and negative ions, and electrons have been added to the standard chemistry in WACCM. WACCM-SIC simulations have been performed to explore the relative contributions to mesospheric NO from auroral and medium energetic electrons, during the period 2013-2015. The modelled simulations are also compared with the available satellite measurements (e.g., temperature, O, H, and O3 from SABER, and NO from AIM) and ground-based microwave radiometer observations of mesospheric NO at Halley station (75oS). The interannual and inter-hemisphere differences will also be discussed.

  1. Spatiotemporal distribution of NOx storage and impact on NH3 and N2O selectivities during lean/rich cycling of a Ba-based lean NOx trap catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae-Soon [ORNL; Partridge Jr, William P [ORNL; Pihl, Josh A [ORNL; Kim, Miyoung [ORNL; Koci, Petr [Institute of Chemical Technology, Prague, Czech Republic; Daw, C Stuart [ORNL

    2012-01-01

    We summarize results from an investigation of the spatiotemporal distribution of NO{sub x} storage and intermediate gas species in determining the performance of a fully formulated, Ba-based, lean NO{sub x} trap catalyst under lean/rich cycling conditions. By experimentally resolving spatiotemporal profiles of gas composition, we found that stored NO{sub x} was significantly redistributed along the monolith axis during the rich phase of the cycle by release and subsequent downstream re-adsorption. Sulfur poisoning of upstream NO{sub x} storage sites caused the active NO{sub x}-storage zone to be displaced downstream. This axial displacement in turn influenced rich-phase NO{sub x} release and re-adsorption. As sulfur poisoning increased, NH3 slip at the catalyst exit also increased due to its formation closer to the catalyst outlet and decreased exposure to downstream oxidation by surface oxygen. N{sub 2}O formation was found to be associated with nitrate reduction rather than oxidation of NH3 by stored oxygen. We propose that the observed evolution of N{sub 2}O selectivity with sulfation can be explained by changes in the spatiotemporal distribution of NO{sub x} storage resulting in either increased or decreased number of precious-metal sites surrounded by nitrates.

  2. Pilot‐scale investigation and CFD modeling of particle deposition in low‐dust monolithic SCR DeNOx catalysts

    DEFF Research Database (Denmark)

    Heiredal, Michael Lykke; Jensen, Anker Degn; Thøgersen, Joakim Reimer

    2013-01-01

    Deposition of particles in selective catalytic reduction DeNOx monolithic catalysts was studied by low‐dust pilot‐scale experiments. The experiments showed a total deposition efficiency of about 30%, and the deposition pattern was similar to that observed in full‐scale low‐dust applications....... On extended exposure to the dust‐laden flue gas, complete blocking of channels was observed, showing that also in low‐dust applications soot blowing is necessary to keep the catalyst clean. A particle deposition model was developed in computational fluid dynamics, and simulations were carried out assuming...... either laminar or turbulent flow. Assuming laminar flow, the accumulated mass was underpredicted with a factor of about 17, whereas assuming turbulent flow overpredicted the experimental result with a factor of about 2. The simulations showed that turbulent diffusion in the monolith channels and inertial...

  3. An Enhanced Rate-Based Emission Trading Program for NOx: The Dutch Model

    Directory of Open Access Journals (Sweden)

    Anne M. Sholtz

    2001-01-01

    Full Text Available Since 1997 government and industry in The Netherlands have been engaged in intensive policy discussions on how to design an emission trading program that would satisfy the Government’s policy objectives within the national and international regulatory framework and accommodate industry’s need for a flexible and cost-effective approach. Early on in the discussion the most promising solution was a rate-based approach, which dynamically allocated saleable emission credits based on a performance standard rate and actual energy used by facilities. All industrial facilities above a threshold of 20 MWth would be judged on their ability to meet this performance rate. Those “cleaner” than the standard can sell excess credits to others with an allocation that is less than their actual NOX emission. With some changes in law, such a design could be made to fit well into the national and EU legislative framework while at the same time uniquely meeting industry’s requirement of flexibility toward economic growth and facility expansion. (An analysis of the legislative changes required will be given in a separate paper by Chris Dekkers. However, the environmental outcome of such a system is not as certain as under an absolute emission cap. At the request of the Netherlands Ministry of Housing, Spatial Planning and the Environment (VROM, Automated Credit Exchange (ACE, in close cooperation with the working group of government and industry representatives introduced a number of features into the Dutch NOX program allowing full exploitation of market mechanisms while allowing intermediate adjustments in the performance standard rates. The design is geared toward meeting environmental targets without jeopardizing the trading market the program intends to create. The paper discusses the genesis of the two-tier credit system ACE helped to design, explains the differences between primary (fixed and secondary (variable credits, and outlines how the Dutch

  4. An enhanced rate-based emission trading program for NOX: the Dutch model.

    Science.gov (United States)

    Sholtz, A M; Van Amburg, B; Wochnick, V K

    2001-12-01

    Since 1997 government and industry in The Netherlands have been engaged in intensive policy discussions on how to design an emission trading program that would satisfy the Government's policy objectives within the national and international regulatory framework and accommodate industry's need for a flexible and cost-effective approach. Early on in the discussion the most promising solution was a rate-based approach, which dynamically allocated saleable emission credits based on a performance standard rate and actual energy used by facilities. All industrial facilities above a threshold of 20 MWth would be judged on their ability to meet this performance rate. Those "cleaner" than the standard can sell excess credits to others with an allocation that is less than their actual NOX emission. With some changes in law, such a design could be made to fit well into the national and EU legislative framework while at the same time uniquely meeting industry's requirement of flexibility toward economic growth and facility expansion. (An analysis of the legislative changes required will be given in a separate paper by Chris Dekkers.) However, the environmental outcome of such a system is not as certain as under an absolute emission cap. At the request of the Netherlands Ministry of Housing, Spatial Planning and the Environment (VROM), Automated Credit Exchange (ACE), in close cooperation with the working group of government and industry representatives introduced a number of features into the Dutch NOX program allowing full exploitation of market mechanisms while allowing intermediate adjustments in the performance standard rates. The design is geared toward meeting environmental targets without jeopardizing the trading market the program intends to create. The paper discusses the genesis of the two-tier credit system ACE helped to design, explains the differences between primary (fixed) and secondary (variable) credits, and outlines how the Dutch system is expected to

  5. Multiphase modeling of nitrate photochemistry in the quasi-liquid layer (QLL: implications for NOx release from the Arctic and coastal Antarctic snowpack

    Directory of Open Access Journals (Sweden)

    A. Saiz-Lopez

    2008-08-01

    Full Text Available We utilize a multiphase model, CON-AIR (Condensed Phase to Air Transfer Model, to show that the photochemistry of nitrate (NO3− in and on ice and snow surfaces, specifically the quasi-liquid layer (QLL, can account for NOx volume fluxes, concentrations, and [NO]/[NO2] (γ=[NO]/[NO2] measured just above the Arctic and coastal Antarctic snowpack. Maximum gas phase NOx volume fluxes, concentrations and γ simulated for spring and summer range from 5.0×104 to 6.4×105 molecules cm−3 s−1, 5.7×108 to 4.8×109 molecules cm−3, and ~0.8 to 2.2, respectively, which are comparable to gas phase NOx volume fluxes, concentrations and γ measured in the field. The model incorporates the appropriate actinic solar spectrum, thereby properly weighting the different rates of photolysis of NO3− and NO2−. This is important since the immediate precursor for NO, for example, NO2−, absorbs at wavelengths longer than nitrate itself. Finally, one-dimensional model simulations indicate that both gas phase boundary layer NO and NO2 exhibit a negative concentration gradient as a function of height although [NO]/[NO2] are approximately constant. This gradient is primarily attributed to gas phase reactions of NOx with halogens oxides (i.e. as BrO and IO, HOx, and hydrocarbons, such as CH3O2.

  6. Economic Modeling of Compressed Air Energy Storage

    Directory of Open Access Journals (Sweden)

    Rui Bo

    2013-04-01

    Full Text Available Due to the variable nature of wind resources, the increasing penetration level of wind power will have a significant impact on the operation and planning of the electric power system. Energy storage systems are considered an effective way to compensate for the variability of wind generation. This paper presents a detailed production cost simulation model to evaluate the economic value of compressed air energy storage (CAES in systems with large-scale wind power generation. The co-optimization of energy and ancillary services markets is implemented in order to analyze the impacts of CAES, not only on energy supply, but also on system operating reserves. Both hourly and 5-minute simulations are considered to capture the economic performance of CAES in the day-ahead (DA and real-time (RT markets. The generalized network flow formulation is used to model the characteristics of CAES in detail. The proposed model is applied on a modified IEEE 24-bus reliability test system. The numerical example shows that besides the economic benefits gained through energy arbitrage in the DA market, CAES can also generate significant profits by providing reserves, compensating for wind forecast errors and intra-hour fluctuation, and participating in the RT market.

  7. Heat Transfer Modeling of Dry Spent Nuclear Fuel Storage Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y.

    1999-01-13

    The present work was undertaken to provide heat transfer model that accurately predicts the thermal performance of dry spent nuclear fuel storage facilities. One of the storage configurations being considered for DOE Aluminum-clad Spent Nuclear Fuel (Al-SNF), such as the Material and Testing Reactor (MTR) fuel, is in a dry storage facility. To support design studies of storage options a computational and experimental program has been conducted at the Savannah River Site (SRS). The main objective is to develop heat transfer models including natural convection effects internal to an interim dry storage canister and to geological codisposal Waste Package (WP). Calculated temperatures will be used to demonstrate engineering viability of a dry storage option in enclosed interim storage and geological repository WP and to assess the chemical and physical behaviors of the Al-SNF in the dry storage facilities. The current paper describes the modeling approaches and presents the computational results along with the experimental data.

  8. Modeling and Simulation on NOx and N2O Formation in Co-combustion of Low-rank Coal and Palm Kernel Shell

    Directory of Open Access Journals (Sweden)

    Mahidin Mahidin

    2012-12-01

    Full Text Available NOx and N2O emissions from coal combustion are claimed as the major contributors for the acid rain, photochemical smog, green house and ozone depletion problems. Based on the facts, study on those emissions formation is interest topic in the combustion area. In this paper, theoretical study by modeling and simulation on NOx and N2O formation in co-combustion of low-rank coal and palm kernel shell has been done. Combustion model was developed by using the principle of chemical-reaction equilibrium. Simulation on the model in order to evaluate the composition of the flue gas was performed by minimization the Gibbs free energy. The results showed that by introduced of biomass in coal combustion can reduce the NOx concentration in considerably level. Maximum NO level in co-combustion of low-rank coal and palm kernel shell with fuel composition 1:1 is 2,350 ppm, low enough compared to single low-rank coal combustion up to 3,150 ppm. Moreover, N2O is less than 0.25 ppm in all cases. Keywords: low-rank coal, N2O emission, NOx emission, palm kernel shell

  9. Modeling of vehicular hydrogen storage transfer processes

    Energy Technology Data Exchange (ETDEWEB)

    Viola, J.; Ventner, R.D. [Toronto Univ., ON (Canada). Dept. of Mechanical and Industrial Engineering; Bose, T.; Benard, P. [Quebec Univ., Trois-Rivieres, PQ (Canada)

    2003-07-01

    The acceptance of hydrogen as an alternate fuel for powering vehicles depends on several factors, such as the performance properties of hydrogen fuels, the behaviour of the vehicle in terms of power response, and the handling of the fuel during the transfer operation to the vehicle. This paper presents a study which examined the transfer of fuel and compared the fueling processes of several hydrogen storage methods on a vehicle. The study involved a computer-simulation of different hydrogen storage systems to compare the characteristics of the various transfer processes. The thermodynamics of hydrogen transfer from a defined initial condition to its final state was studied. Tabulations of energy requirements, temperature and pressure variations, and limitations concerning the transfer rate were provided. The fueling procedure was simulated using dynamic models, and the components from the initial to the final equilibrium state within the vehicle were characterized. The fluctuations in the system during the physical transfer operations were illustrated. Some of the safety risks include passive risks from toxic and low temperature or cryogenic effects, and explosion and combustion. The authors used fuzzy analysis of survey results to examine safety, which is more subjective in nature than the other properties modeled. An introduction to fuzzy logic was presented, followed by a description of the method used. 2 refs., 7 figs.

  10. Modeling the regional impact of ship emissions on NOx and ozone levels over the Eastern Atlantic and Western Europe using ship plume parameterization

    Directory of Open Access Journals (Sweden)

    P. Pisoft

    2010-07-01

    Full Text Available In general, regional and global chemistry transport models apply instantaneous mixing of emissions into the model's finest resolved scale. In case of a concentrated source, this could result in erroneous calculation of the evolution of both primary and secondary chemical species. Several studies discussed this issue in connection with emissions from ships and aircraft. In this study, we present an approach to deal with the non-linear effects during dispersion of NOx emissions from ships. It represents an adaptation of the original approach developed for aircraft NOx emissions, which uses an exhaust tracer to trace the amount of the emitted species in the plume and applies an effective reaction rate for the ozone production/destruction during the plume's dilution into the background air. In accordance with previous studies examining the impact of international shipping on the composition of the troposphere, we found that the contribution of ship induced surface NOx to the total reaches 90% over remote ocean and makes 10–30% near coastal regions. Due to ship emissions, surface ozone increases by up to 4–6 ppbv making 10% contribution to the surface ozone budget. When applying the ship plume parameterization, we show that the large scale NOx decreases and the ship NOx contribution is reduced by up to 20–25%. A similar decrease was found in the case of O3. The plume parameterization suppressed the ship induced ozone production by 15–30% over large areas of the studied region. To evaluate the presented parameterization, nitrogen monoxide measurements over the English Channel were compared with modeled values and it was found that after activating the parameterization the model accuracy increases.

  11. Modeling the regional impact of ship emissions on NOx and ozone levels over the Eastern Atlantic and Western Europe using ship plume parameterization

    Directory of Open Access Journals (Sweden)

    P. Pisoft

    2009-12-01

    Full Text Available In general, regional and global chemistry transport models apply instantaneous mixing of emissions into the model's finest resolved scale. In case of a concentrated source, this could result in erroneous calculation of the evolution of both primary and secondary chemical species. Several studies discussed this issue in connection with emissions from ships and aircrafts. In this study, we present an approach to deal with the non-linear effects during dispersion of NOx emissions from ships. It represents an adaptation of the original approach developed for aircraft NOx emissions, which uses an exhaust tracer to trace the amount of the emitted species in the plume and applies an effective reaction rate for the ozone production/destruction during the plume's dilution into the background air. In accordance with previous studies examining the impact of international shipping on the composition of the troposphere, we found that the contribution of ship induced surface NOx to the total reaches 90% over remote ocean and makes 10–30% near coastal regions. Due to ship emissions, surface ozone increases by up to 4–6 ppbv making 10% contribution to the surface ozone budget. When applying the ship plume parameterization, we showed that the large scale NOx decreases and the ship NOx contribution is reduced by up to 20–25%. Similar decrease was found in case of O3. The plume parameterization suppressed the ship induced ozone production by 15–30% over large areas of the focused region. To evaluate the presented parameterization, nitrogen oxide measurements over the English Channel were compared with modeled values and it was found that after activating the parameterization the model accuracy increases.

  12. NOX2 Mediated-Parvalbumin Interneuron Loss Might Contribute to Anxiety-Like and Enhanced Fear Learning Behavior in a Rat Model of Post-Traumatic Stress Disorder.

    Science.gov (United States)

    Liu, Fang-Fang; Yang, Lin-Dong; Sun, Xiao-Ru; Zhang, Hui; Pan, Wei; Wang, Xing-Ming; Yang, Jian-Jun; Ji, Mu-Huo; Yuan, Hong-Mei

    2016-12-01

    Post-traumatic stress disorder (PTSD) is a common psychiatric disease following exposure to a severe traumatic event or physiological stress, yet the precise mechanisms underlying PTSD remains largely to be determined. Using an animal model of PTSD induced by a single prolonged stress (SPS), we assessed the role of hippocampal nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and parvalbumin (PV) interneurons in the development of PTSD symptoms. In the present study, behavioral tests were performed by the open field (day 13 after SPS) and fear conditioning tests (days 13 and 14 after SPS). For the interventional study, rats were chronically treated with a NADPH oxidase inhibitor apocynin either by early or delayed administration. The levels of tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, IL-10, malondialdehyde, superoxide dismutase, NOX2, 4-hydroxynonenal, and PV in the hippocampus were measured at the indicated time points. In the present study, we showed that SPS rats displayed anxiety-like and enhanced fear learning behavior, which was accompanied by the increased expressions of malondialdehyde, IL-6, NOX2, 4-hydroxynonenal, and decreased PV expression. Notably, early but not delayed treatment with apocynin reversed all these abnormalities after SPS. In conclusion, our results provided evidence that NOX2 activation in the hippocampus, at least in part, contributes to oxidative stress and neuroinflammation, which further results in PV interneuron loss and consequent PTSD symptoms in a rat model of PTSD induced by SPS.

  13. Modeling leaks from liquid hydrogen storage systems.

    Energy Technology Data Exchange (ETDEWEB)

    Winters, William Stanley, Jr.

    2009-01-01

    This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

  14. Slow Dynamics Model of Compressed Air Energy Storage and Battery Storage Technologies for Automatic Generation Control

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Venkat; Das, Trishna

    2016-05-01

    Increasing variable generation penetration and the consequent increase in short-term variability makes energy storage technologies look attractive, especially in the ancillary market for providing frequency regulation services. This paper presents slow dynamics model for compressed air energy storage and battery storage technologies that can be used in automatic generation control studies to assess the system frequency response and quantify the benefits from storage technologies in providing regulation service. The paper also represents the slow dynamics model of the power system integrated with storage technologies in a complete state space form. The storage technologies have been integrated to the IEEE 24 bus system with single area, and a comparative study of various solution strategies including transmission enhancement and combustion turbine have been performed in terms of generation cycling and frequency response performance metrics.

  15. NO2 columns in the western United States observed from space and simulated by a regional chemistry model and their implications for NOx emissions

    Science.gov (United States)

    Kim, S.-W.; Heckel, A.; Frost, G. J.; Richter, A.; Gleason, J.; Burrows, J. P.; McKeen, S.; Hsie, E.-Y.; Granier, C.; Trainer, M.

    2009-06-01

    There are many isolated sources of NOx emissions across the western United States, including electrical power generation plants and urban areas. In this manuscript, two satellite instruments measuring NO2 vertical columns over these sources and an atmospheric chemical-transport model are used to evaluate bottom-up NOx emission inventories, model assumptions, and satellite retrieval algorithms. We carried out simulations with the Weather Research and Forecasting-Chemistry (WRF-Chem) model for the western U.S. domain during the summer of 2005 using measured power plant NOx emissions. Model NO2 vertical columns are compared with a retrieval of the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) satellite instrument data by the University of Bremen and retrievals of the Ozone Monitoring Instrument (OMI) data by the U.S. National Aeronautics and Space Administration (NASA) and a modified version of the NASA OMI retrieval produced by the University of Bremen. For areas dominated by power plant NOx emissions, the model NO2 columns serve as a comparison standard for satellite retrievals because emissions are continuously monitored at all large U.S. power plants. An extensive series of sensitivity tests of the assumptions in both the satellite retrievals and the model are carried out over the Four Corners and San Juan power plants, two adjacent facilities in the northwest corner of New Mexico that together represent the largest NOx point source in the United States. Overall, the SCIAMACHY and OMI NO2 columns over western U.S. power plants agree well with model NO2 columns, with differences between the two being within the variability of the model and satellite. In contrast to regions dominated by power plant emissions, model NO2 columns over large urban areas along the U.S. west coast are approximately twice as large as satellite NO2 columns from SCIAMACHY and OMI retrievals. The discrepancies in urban areas are beyond the sensitivity

  16. GE networked mass storage solutions supporting IEEE network mass storage model

    Science.gov (United States)

    Herzog, Donald

    1993-01-01

    The General Electric Government Communications Systems Department (GE/GCSD) has developed a near real time digital data storage and retrieval system that extends the capabilities currently available in today's marketplace. This system called DuraStore uses commercially available rotary tape drive technology with ANSI/IEEE standards for automated magnetic tape based data storage. It uses a nonproprietary approach to satisfy a wide range of data rates and storage capabilities requirements and is compliant with the IEEE Network Storage Model. Rotary tape drives, standard interfaces, application specific hardware/software, networked automated tape libraries, library administrator, write protection, volume/physical media linkages, and maximum resource utilization are addressed.

  17. O3 and NOx Exchange

    NARCIS (Netherlands)

    Loubet, B.; Castell, J.F.; Laville, P.; Personne, E.; Tuzet, A.; Ammann, C.; Emberson, L.; Ganzeveld, L.; Kowalski, A.S.; Merbold, L.; Stella, P.; Tuovinen, J.P.

    2015-01-01

    This discussion was based on the background document “Review on modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides”, which reviews the processes contributing to biosphere-atmosphere exchange of O3 and NOx, including stomatal and non-stomatal exchange of O3 and NO, NO2.

  18. Integration of the Smart NOx-Sensor in the exhaust line of a gasoline high pressure direct injection system; Integration eines Smart NOx-Sensors im Abgasstrang fuer die Benzindirekteinspritzung

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hong; Pfleger, C.; Lemire, B. [Siemens AG Automobiltechnik, Regensburg (Germany)

    2000-07-01

    For further reduction of fuel consumption of Gasoline engines the High Pressure Direct Injection is the most suitable way. For the exhaust gas aftertreatment NOx storage catalysts are used, which stores the NOx emission in lean burn phases and reduce it in short phases with rich mixture. To trigger the start of the regeneration phases suitable models can be used. The optimum start of the regeneration phase concerning emission and consumption is only possible with the use of a NOx-Sensor, so that further stringent emission regulation and OBD II requirements will force the use of the NOx-Sensor. Siemens Automotive in cooperation with NGK Insulators are developping in cooperation the 'Smart' NOx-Sensor, which can be integrated in the ECU. With this configuration all requirements concerning emission, fuel consumption and diagnosis can be fulfilled. (orig.) [German] Die Benzindirekteinspritzung bietet ein hohes Potential fuer die Reduzierung des Kraftstoffverbrauchs. Fuer die Abgasnachbehandlung werden NOx-Speicherkatalysatoren eingesetzt, die in den mageren Motorbetriebsphasen die entstehenden Stickoxide speichern und in kurzen Motorbetriebsphasen mit fettem Gemisch diese regenerieren. Fuer die Einleitung der Regenerationsphasen bieten sich geeignete Modelle an. Die sowohl emissions- wie auch verbrauchsoptimale Einleitung der Regenerationsphase ist jedoch nur mit dem Einsatz eines NOx-Sensors moeglich, wobei die zunehmend strenger werdenden Emissions- und Diagnosevorschriften der emissionsbeeinflussenden Bauteile den Einsatz des NOx-Sensors erfordern werden. Siemens Automobiltechnik entwickelt in Zusammenarbeit mit NGK Insulator einen NOx-Sensor, der in die Motorsteuerung eingebunden werden kann. Mit dieser Konfiguration lassen sich alle Anforderungen an das Motorsteuergeraet und die Abgasnachbehandlung bezueglich Kraftstoffverbrauch, Emissionen und Diagnose erfuellen. (orig.)

  19. A control model for district heating networks with storage

    NARCIS (Netherlands)

    Scholten, Tjeert; De Persis, Claudio; Tesi, Pietro

    2014-01-01

    In [1] pressure control of hydraulic networks is investigated. We extend this work to district heating systems with storage capabilities and derive a model taking the topology of the network into account. The goal for the derived model is that it should allow for control of the storage level and tem

  20. A control model for district heating networks with storage

    NARCIS (Netherlands)

    Scholten, Tjeert; De Persis, Claudio; Tesi, Pietro

    2014-01-01

    In [1] pressure control of hydraulic networks is investigated. We extend this work to district heating systems with storage capabilities and derive a model taking the topology of the network into account. The goal for the derived model is that it should allow for control of the storage level and tem

  1. Top-Down Constraints on Air Quality Model Emissions of NH3, NOx, and SO2 using Surface, Aircraft, and Satellite Data

    Science.gov (United States)

    Alvarado, M. J.; Lonsdale, C. R.; Winijkul, E.; Brodowski, C. M.; Cady-Pereira, K.; Henze, D. K.; Capps, S.

    2016-12-01

    Accurate modeling of the formation of ozone (O3) and fine particulate matter (PM2.5) requires accurate estimates of the emissions of precursor species such as ammonia (NH3), nitrogen oxides (NOx = NO+NO2) and sulfur dioxide (SO2). Here we present an evaluation of the 2011 EPA National Emission Inventory for NH3, NOx, and SO2 using CMAQv5.0.2 and data from the 2013 NOAA Southeast Nexus (SENEX) field campaign. Model results are compared to surface and aircraft measurements during each campaign, as well as satellite NH3 observations from the NOAA Cross-track Infrared Sounder (CrIS) and satellite observations of NO2 and SO2 from the NASA Ozone Monitoring Instrument (OMI). We also present an evaluation of the California Air Resources Board (CARB) NH3 emissions for 2012 using CMAQ and the CrIS NH3 observations. We discuss the lessons learned in using CrIS NH3 observations in the southeast US, where CMAQ predicts most of the gas-phase NH3 is very close to the surface, and contrast this with the use of CrIS NH3 observations over California. We discuss the use of two methods - a mass balance approach and an approach using the CMAQ adjoint - to optimize these emissions and evaluate the improvement in model performance for gas-phase NH3, NOx, and SO2, as well as for the formation of O3 and PM2.5.

  2. Didactic model of the high storage system

    Directory of Open Access Journals (Sweden)

    J. Świder

    2006-04-01

    Full Text Available Purpose: The continuous progress in Computer Integrated Manufacturing (CIM field with automatic storing systems is broadening the range of education process for engineers in future. This document describes the newest didactic station integrated witch a Modular Production System (MPS model [1, 2, 3]. It is a module of high storage. This arrangement is the perfect didactic item for students.Design/methodology/approach: The main reason, why the laboratory position, we have mentioned, has been created is brodening the students knowlegde’s range. To achive this task the warehouse has been made from really industrial elements. All manipulator’s axis were building from different types of transmissions. Findings: During the work with warehouse there has been prepared the new algorithm which controlls the linear drive. Besides that there has been created brand new standards in engineers education, which are based on the described warehouse. Research limitations/implications: The main target of the didactic activity of Institute of Engineering Processes Automation and Integrated Manufacturing Systems is broden the loboratory base. That’s the reason why now there already has been building another laboratory position, which is based on Fanuc manipulator.Practical implications: The algorithm of Pneu-Stat steering hasn’t been finished yet, but when it has been done it can be used in industrial aplicationsOriginality/value: This paper describes the new didactic station with innovational steering algorithm [4, 5].

  3. Modelling of NOx emissions from pressurized fluidized bed combustion - A parameter study

    DEFF Research Database (Denmark)

    Jensen, Anker; Johnsson, Jan Erik

    1997-01-01

    Simulations with a mathematical model of a pressurized bubbling fluidized-bed combustor (PFBC) combined with a kinetic model for NO formation and reduction are reported. The kinetic model for NO formation and reduction considers NO and NH3 as the fixed nitrogen species, and includes homogeneous....... The sensitivity of the simulated NO emission with respect to hydrodynamic and combustion parameters in the model is investigated and the mechanisms by which the parameters influence the emission of NO is explained. The analysis shows that the most important hydrodynamic parameters are the minimum fluidization...

  4. Modeling Deactivation of Catalysts for Selective Catalytic Reduction of NOx by KCl Aerosols

    DEFF Research Database (Denmark)

    Olsen, Brian Kjærgaard; Castellino, Francesco; Jensen, Anker Degn

    2017-01-01

    with the catalyst at the surface of the monolith wall, the transport and accumulation of potassium, bound to Brønsted acid sites, throughout the catalyst wall, and the resulting loss in SCR activity. Using an experimentally measured KCl aerosol size distribution as input, the model can replicate the observed...... if the particle size of the incoming aerosol is increased. The model provides, for the first time, a mechanistic framework for understanding and modeling SCR catalyst deactivation by KCl that may be applicable also for deactivation by other salts and at different operating conditions.......A detailed model for the deactivation of a V2O5–WO3/TiO2-based SCR monolith catalyst by potassium poisoning has been developed and validated. The model accounts for deposition of KCl aerosol particles present in the flue gas on the external catalyst surface, the reaction of the deposited particles...

  5. Microkinetic Modeling of Lean NOx Trap Storage and Regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Richard S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Chakravarthy, V. Kalyana [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pihl, Josh A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Daw, C. Stuart [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2011-12-01

    A microkinetic chemical reaction mechanism capable of describing both the storage and regeneration processes in a fully formulated lean NOx trap (LNT) is presented. The mechanism includes steps occurring on the precious metal, barium oxide (NOx storage), and cerium oxide (oxygen storage) sites of the catalyst. The complete reaction set is used in conjunction with a transient plug flow reactor code (including boundary layer mass transfer) to simulate not only a set of long storage/regeneration cycles with a CO/H2 reductant, but also a series of steady flow temperature sweep experiments that were previously analyzed with just a precious metal mechanism and a steady state code neglecting mass transfer. The results show that, while mass transfer effects are generally minor, NOx storage is not negligible during some of the temperature ramps, necessitating a re-evaluation of the precious metal kinetic parameters. The parameters for the entire mechanism are inferred by finding the best overall fit to the complete set of experiments. Rigorous thermodynamic consistency is enforced for parallel reaction pathways and with respect to known data for all of the gas phase species involved. It is found that, with a few minor exceptions, all of the basic experimental observations can be reproduced with the transient simulations. In addition to accounting for normal cycling behavior, the final mechanism should provide a starting point for the description of further LNT phenomena such as desulfation and the role of alternative reductants.

  6. A Cost Model for Storage and Weeding Programs.

    Science.gov (United States)

    Lawrence, Gary S.

    1981-01-01

    Presents a simple cost model to analyze trade-offs involved in considering storage and weeding as alternatives to new construction for academic libraries. References are provided, and the Palmour cost model is presented as an appendix. (RAA)

  7. Emissions and transport of NOx over East Asia diagnosed by satellite and in-situ observations and chemical transport model results

    Science.gov (United States)

    Lee, H.; Kim, S.; Brioude, J.; Cooper, O. R.; Frost, G. J.; Trainer, M.; Kim, C.

    2012-12-01

    Nitrogen dioxide (NO2) columns observed from space have been useful in detecting the increase of NOx emissions over East Asia in accordance with rapid growth in its economy. In addition to emissions, transport can be an important factor to determine the observed satellite NO2 columns in this region. Satellite tropospheric NO2 columns showed maximum in winter and minimum in summer over the high emission areas in China, as lifetime of NO2 decreases with increase of sunlight. However, secondary peaks in the satellite NO2 columns were found in spring in both Korea and Japan, which may be influenced by transport of NOx within East Asia. Surface in-situ observations confirm the findings from the satellite measurements. The large-scale distribution of satellite NO2 columns over East Asia and the Pacific Ocean showed that the locations of NO2 column maxima coincided with wind convergence zones that change with seasons. In spring, the convergence zone is located over 30-40°N, leading to the most efficient transport of the emissions from southern China to downwind areas including Korea, Japan, and western coastal regions of the United States. We employed a Lagrangian particle dispersion model to identify the sources of the observed springtime maximum NO2. In order to understand chemical processing during the transport and quantify the roles of emissions and transport in local NOx budgets, we will also present the results from a regional chemical transport model.

  8. Predicate Model on NOx Emission of a High Capacity Firing Boiler%大型燃煤锅炉氮氧化物排放预测模型

    Institute of Scientific and Technical Information of China (English)

    凡荣荣; 杨巨生; 谢克昌

    2012-01-01

    随着环保要求的不断提高,大型燃煤电厂锅炉的NOx排放特性日益受到关注。借助某600MW锅炉燃烧调整试验数据,采用BP-adaboost算法建立了NOx排放特性的预测模型。研究结构表明,与BP神经网络建立的NOx特性排放模型相比,该模型能根据燃煤特性及各种操作参数更加准确预测锅炉在不同工况下NOx排放特性。%With the development of the restricted environmental protection demand,more attention is paid to the NOx emission property of the high capacity tangential firing boiler.The estimation model has been established by means of BP-adaboost based on a 600MW boiler combustion adjustment testing data.It is proven by the research result that such a model can predicate the NOx emission more accurate than that established by BP network under various operating conditions.

  9. Technoeconomic Modeling of Battery Energy Storage in SAM

    Energy Technology Data Exchange (ETDEWEB)

    DiOrio, Nicholas [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Janzou, Steven [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lundstrom, Blake [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    Detailed comprehensive lead-acid and lithium-ion battery models have been integrated with photovoltaic models in an effort to allow System Advisor Model (SAM) to offer the ability to predict the performance and economic benefit of behind the meter storage. In a system with storage, excess PV energy can be saved until later in the day when PV production has fallen, or until times of peak demand when it is more valuable. Complex dispatch strategies can be developed to leverage storage to reduce energy consumption or power demand based on the utility rate structure. This document describes the details of the battery performance and economic models in SAM.

  10. HYBRID SNCR-SCR TECHNOLOGIES FOR NOX CONTROL: MODELING AND EXPERIMENT

    Science.gov (United States)

    The hybrid process of homogeneous gas-phase selective non-catalytic reduction (SNCR) followed by selective catalytic reduction (SCR) of nitric oxide (NO) was investigated through experimentation and modeling. Measurements, using NO-doped flue gas from a gas-fired 29 kW test combu...

  11. Pellet as a Technological Nutrient within the Circular Economy Model: Comparative Analysis of Combustion Efficiency and CO and NOx Emissions for Pellets from Olive and Almond Trees

    Directory of Open Access Journals (Sweden)

    Valentín Molina-Moreno

    2016-09-01

    Full Text Available This study analyzes the operation of Biomass System (BIO System technology for the combustion of pellets from almond and olive trees within the circular economy model. Its aims are the reduction of greenhouse gas emissions as well as waste removal and its energy use by reintroducing that waste into the production process as technological nutrient. In order to do so, combustion efficiency under optimal conditions at nominal power was analyzed. In addition, a TESTO 350-XL analyzer was employed to measure CO and NOx emissions. High combustion efficiency values were obtained, 87.7% and 86.3%, for pellets from olive tree and almond tree, respectively. The results of CO and NOx emission levels were very satisfactory. Under conditions close to nominal power, CO emission levels were 225.3 ppm at 6% O2 for pellet from almond tree and 351.6 ppm at 6% O2 for pellet from olive tree. Regarding NOx emissions, the values were 365.8 ppm at 6% O2 and 333.2 ppm at 6% O2 for pellets from almond tree and olive tree, respectively. In general, these values were below those legally established by current legislation in European countries. Therefore, BIO System technology is a perfectly feasible option in terms of energy use and circular economy.

  12. Developing a Model for a CHP System with Storage

    Directory of Open Access Journals (Sweden)

    M. Abunku

    2016-04-01

    Full Text Available A model for a Combined Heat and Power (CHP system developed using Matlab is presented in this project. The model developed includes sub-models of Internal Combustion Engine (ICE and generator, electrical and thermal storage systems, and power converters (rectifier and inverter. The model developed is able to simulate the performance of a CHP system when supplying user load. The battery electrical storage system is modelled and used as the electrical storage for this project, and the water storage tank is modelled and used as thermal storage. The project presents the model developed, and the results of the analysis done on the model. The model considered only heat from engine cooling, which is used to heat water to supply the DHW (District Hot Water needs of the user. The results show that by the addition of storage to the CHP system, the overall system efficiency is increased by 32% indicating that the model developed is reliable, and the project is a feasible one

  13. Damsel: A Data Model Storage Library for Exascale Science

    Energy Technology Data Exchange (ETDEWEB)

    Koziol, Quincey [The HDF Group

    2014-11-26

    The goal of this project is to enable exascale computational science applications to interact conveniently and efficiently with storage through abstractions that match their data models. We will accomplish this through three major activities: (1) identifying major data model motifs in computational science applications and developing representative benchmarks; (2) developing a data model storage library, called Damsel, that supports these motifs, provides efficient storage data layouts, incorporates optimizations to enable exascale operation, and is tolerant to failures; and (3) productizing Damsel and working with computational scientists to encourage adoption of this library by the scientific community.

  14. Damsel - A Data Model Storage Library for Exascale Science

    Energy Technology Data Exchange (ETDEWEB)

    Samatova, Nagiza F

    2014-07-18

    The goal of this project is to enable exascale computational science applications to interact conveniently and efficiently with storage through abstractions that match their data models. We will accomplish this through three major activities: (1) identifying major data model motifs in computational science applications and developing representative benchmarks; (2) developing a data model storage library, called Damsel, that supports these motifs, provides efficient storage data layouts, incorporates optimizations to enable exascale operation, and is tolerant to failures; and (3) productizing Damsel and working with computational scientists to encourage adoption of this library by the scientific community.

  15. Modeling impact of storage zones on stream dissolved oxygen

    Science.gov (United States)

    Chapra, S.C.; Runkel, R.L.

    1999-01-01

    The Streeter-Phelps dissolved oxygen model is modified to incorporate storage zones. A dimensionless number reflecting enhanced decomposition caused by the increased residence time of the biochemical oxygen demand in the storage zone parameterizes the impact. This result provides a partial explanation for the high decomposition rates observed in shallow streams. An application suggests that the storage zone increases the critical oxygen deficit and moves it closer to the point source. It also indicates that the storage zone should have lower oxygen concentration than the main channel. An analysis of a dimensionless enhancement factor indicates that the biochemical oxygen demand decomposition in small streams could be up to two to three times more than anticipated based on the standard Streeter-Phelps model without storage zones. For larger rivers, enhancements of up to 1.5 could occur.The Streeter-Phelps dissolved oxygen model is modified to incorporate storage zones. A dimensionless number reflecting enhanced decomposition caused by the increased residence time of the biochemical oxygen demand in the storage zone parameterizes the impact. This result provides a partial explanation for the high decomposition rates observed in shallow streams. An application suggests that the storage zone increases the critical oxygen deficit and moves it closer to the point source. It also indicates that the storage zone should have lower oxygen concentration than the main channel. An analysis of a dimensionless enhancement factor indicates that the biochemical oxygen demand decomposition in small streams could be up to two to three times more than anticipated based on the standard Streeter-Phelps model without storage zones. For larger rivers, enhancements of up to 1.5 could occur.

  16. Computer modeling of ORNL storage tank sludge mobilization and mixing

    Energy Technology Data Exchange (ETDEWEB)

    Terrones, G.; Eyler, L.L.

    1993-09-01

    This report presents and analyzes the results of the computer modeling of mixing and mobilization of sludge in horizontal, cylindrical storage tanks using submerged liquid jets. The computer modeling uses the TEMPEST computational fluid dynamics computer program. The horizontal, cylindrical storage tank configuration is similar to the Melton Valley Storage Tanks (MVST) at Oak Ridge National (ORNL). The MVST tank contents exhibit non-homogeneous, non-Newtonian rheology characteristics. The eventual goals of the simulations are to determine under what conditions sludge mobilization using submerged liquid jets is feasible in tanks of this configuration, and to estimate mixing times required to approach homogeneity of the contents of the tanks.

  17. A New Model of Data Protection on Cloud Storage

    Directory of Open Access Journals (Sweden)

    Jing Peng

    2014-03-01

    Full Text Available This paper focuses on studying cloud storage data protection model and implementing encrypted storage of user data in double-key form. User data are encrypted with symmetric encryption algorithm and this secret key is encrypted with asymmetric encryption algorithm. The private key is managed and controlled by users. In this way, users guarantee the security of their own data with the sole private key. Providing effective protection for uploading and downloading of user data and good data storage and transmission support for cloud storage application through the data protection mechanism deployed at client, thus solving the biggest obstacle, i.e. security of cloud data in the application of cloud storage enterprises currently to a certain extent.

  18. Modeling Pumped Thermal Energy Storage with Waste Heat Harvesting

    Science.gov (United States)

    Abarr, Miles L. Lindsey

    This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual-functionality. This dissertation first presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was +/- 0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed energy of a recently proposed Pumped Thermal Energy Storage and Bottoming System (Bot-PTES) that uses ammonia as the working fluid. This analysis focused on the effects of hot thermal storage utilization, system pressure, and evaporator/condenser size on the system performance. This work presents the estimated performance for a proposed baseline Bot-PTES. Results of this analysis showed that all selected parameters had significant effects on efficiency, with the evaporator/condenser size having the largest effect over the selected ranges. Results for the baseline case showed stand-alone energy storage efficiencies between 51 and 66% for varying power levels and charge states, and a stand-alone bottoming efficiency of 24%. The resulting efficiencies for this case were low compared to competing technologies; however, the dual-functionality of the Bot-PTES enables it to have higher capacity factor, leading to 91-197/MWh levelized cost of energy compared to 262-284/MWh for batteries and $172-254/MWh for Compressed Air Energy Storage.

  19. Damsel: A Data Model Storage Library for Exascale Science

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Alok [Northwestern Univ., Evanston, IL (United States); Liao, Wei-keng [Northwestern Univ., Evanston, IL (United States)

    2014-07-11

    Computational science applications have been described as having one of seven motifs (the “seven dwarfs”), each having a particular pattern of computation and communication. From a storage and I/O perspective, these applications can also be grouped into a number of data model motifs describing the way data is organized and accessed during simulation, analysis, and visualization. Major storage data models developed in the 1990s, such as Network Common Data Format (netCDF) and Hierarchical Data Format (HDF) projects, created support for more complex data models. Development of both netCDF and HDF5 was influenced by multi-dimensional dataset storage requirements, but their access models and formats were designed with sequential storage in mind (e.g., a POSIX I/O model). Although these and other high-level I/O libraries have had a beneficial impact on large parallel applications, they do not always attain a high percentage of peak I/O performance due to fundamental design limitations, and they do not address the full range of current and future computational science data models. The goal of this project is to enable exascale computational science applications to interact conveniently and efficiently with storage through abstractions that match their data models. The project consists of three major activities: (1) identifying major data model motifs in computational science applications and developing representative benchmarks; (2) developing a data model storage library, called Damsel, that supports these motifs, provides efficient storage data layouts, incorporates optimizations to enable exascale operation, and is tolerant to failures; and (3) productizing Damsel and working with computational scientists to encourage adoption of this library by the scientific community. The product of this project, Damsel library, is openly available for download from http://cucis.ece.northwestern.edu/projects/DAMSEL. Several case studies and application programming interface

  20. Storage Capacity Modeling of Reservoir Systems Employing Performance Measures

    Directory of Open Access Journals (Sweden)

    Issa Saket Oskoui

    2014-12-01

    Full Text Available Developing a prediction relationship for total (i.e. within-year plus over-year storage capacity of reservoir systems is beneficial because it can be used as an alternative to the analysis of reservoirs during designing stage and gives an opportunity to planner to examine and compare different cases in a fraction of time required for complete analysis where detailed analysis is not necessary. Existing relationships for storage capacity are mostly capable of estimating over-year storage capacity and total storage capacity can be obtained through relationships for adjusting over-year capacity and there is no independent relationship to estimate total storage capacity. Moreover these relationships do not involve vulnerability performance criterion and are not verified for Malaysia Rivers. In this study two different reservoirs in Southern part of Peninsular Malaysia, Melaka and Muar, are analyzed through a Monte Carlo simulation approach involving performance metrics. Subsequently the storage capacity results of the simulation are compared with those of the well-known existing equations. It is observed that existing models may not predict total capacity appropriately for Malaysian reservoirs. Consequently, applying the simulation results, two separate regression equations are developed to model total storage capacity of study reservoirs employing time based reliability and vulnerability performance measures.

  1. Response of lightning NOx emissions and ozone production to climate change: Insights from the Atmospheric Chemistry and Climate Model Intercomparison Project

    Science.gov (United States)

    Finney, D. L.; Doherty, R. M.; Wild, O.; Young, P. J.; Butler, A.

    2016-05-01

    Results from an ensemble of models are used to investigate the response of lightning nitrogen oxide emissions to climate change and the consequent impacts on ozone production. Most models generate lightning using a parameterization based on cloud top height. With this approach and a present-day global emission of 5 TgN, we estimate a linear response with respect to changes in global surface temperature of +0.44 ± 0.05 TgN K-1. However, two models using alternative approaches give +0.14 and -0.55 TgN K-1 suggesting that the simulated response is highly dependent on lightning parameterization. Lightning NOx is found to have an ozone production efficiency of 6.5 ± 4.7 times that of surface NOx sources. This wide range of efficiencies across models is partly due to the assumed vertical distribution of the lightning source and partly to the treatment of nonmethane volatile organic compound (NMVOC) chemistry. Careful consideration of the vertical distribution of emissions is needed, given its large influence on ozone production.

  2. A Study on Modeling of Lean NOx Trap Based on GT-POWER%基于GT-POWER的NOx吸附还原催化器建模研究

    Institute of Scientific and Technical Information of China (English)

    陈韶舒; 李志军; 刘磊; 常庆; 张洪洋; 曹曼曼

    2015-01-01

    By using GT-POWER simulation tools and combining with test data, a lean NOx trap (LNT) model is established. The results of simulation on the model are compared with test results, verifying the correctness of LNT model. This method, being an effective way of catalytic converter modeling, is also applicable to other types of catalytic converters.%本文中使用GT-POWER模拟工具,结合试验数据建立了NOx 吸附还原催化器模型,并通过试验结果与模型模拟结果对比分析,验证了该催化器模型正确. 这种通过GT-POWER模拟工具与试验数据相结合建立模型的方法,同样适用于其他类型的催化器,是一种有效的催化器建模方法.

  3. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush; Stephen Niksa

    2003-04-30

    In full-scale boilers, the effect of biomass cofiring on NO{sub x} and unburned carbon (UBC) emissions has been found to be site-specific. Few sets of field data are comparable and no consistent database of information exists upon which cofiring fuel choice or injection system design can be based to assure that NOX emissions will be minimized and UBC be reduced. This report presents the results of a comprehensive project that generated an extensive set of pilot-scale test data that were used to validate a new predictive model for the cofiring of biomass and coal. All testing was performed at the 3.6 MMBtu/hr (1.75 MW{sub t}) Southern Company Services/Southern Research Institute Combustion Research Facility where a variety of burner configurations, coals, biomasses, and biomass injection schemes were utilized to generate a database of consistent, scalable, experimental results (422 separate test conditions). This database was then used to validate a new model for predicting NO{sub x} and UBC emissions from the cofiring of biomass and coal. This model is based on an Advanced Post-Processing (APP) technique that generates an equivalent network of idealized reactor elements from a conventional CFD simulation. The APP reactor network is a computational environment that allows for the incorporation of all relevant chemical reaction mechanisms and provides a new tool to quantify NOx and UBC emissions for any cofired combination of coal and biomass.

  4. Gray-box modelling approach for description of storage tunnel

    DEFF Research Database (Denmark)

    Harremoës, Poul; Carstensen, Jacob

    1999-01-01

    of the water in the overflow structures. The capacity of a pump draining the storage tunnel is estimated for two different rain events, revealing that the pump was malfunctioning during the first rain event. The proposed modeling approach can be used in automated online surveillance and control and implemented....... The model in the present paper provides on-line information on overflow volumes, pumping capacities, and remaining storage capacities. A linear overflow relation is found, differing significantly from the traditional deterministic modeling approach. The linearity of the formulas is explained by the inertia...

  5. Experimental and Modeling Study on de-NOx Characteristics of Selective Non-catalytic Reduction in O2/CO2 Atmosphere

    Institute of Scientific and Technical Information of China (English)

    Hui Li; Kuihua Han⁎; Hongtao Liu; Chunmei Lu

    2014-01-01

    An experimental study of thermal de-NOx using NH3 as reductant in O2/CO2 atmosphere with the effect of SO2 and different additives was performed in a drop tube furnace. Results show that the optimum temperature win-dow is 841-1184 °C, and the optimum reaction temperature is about 900 °C with a de-NOx efficiency of 95.4%. A certain amount of SO2 has an inhibiting effect on NO reduction. The effect of additives, including Na2CO3, C2H5OH and FeCl3, on NO reduction by NH3 is also explored. The addition of Na2CO3 and FeCl3 is useful to widen the tem-perature window and shift the reaction to lower temperature for the efficiency is increased from 30.5%to 74.0%and 67.4%respectively at 800 °C. Qualitatively, the modeling results using a detailed kinetic modeling mecha-nism represent well most of the process features. The effect of Na2CO3, C2H5OH and FeCl3 addition can be reproduced well by the Na2CO3, C2H5OH and Fe(CO)5 sub-mechanism respectively. The reaction mechanism analysis shows that the effects of these additives on NO reduction are achieved mainly by promoting the produc-tion of OH radicals at lower temperature.

  6. Gray-box modelling approach for description of storage tunnel

    DEFF Research Database (Denmark)

    Harremoës, Poul; Carstensen, Jacob

    1999-01-01

    The dynamics of a storage tunnel is examined using a model based on on-line measured data and a combination of simple deterministic and black-box stochastic elements. This approach, called gray-box modeling, is a new promising methodology for giving an on-line state description of sewer systems...

  7. Emission factors of SO2, NOx and particles from ships in Neva Bay from ground-based and helicopter-borne measurements and AIS-based modeling

    Directory of Open Access Journals (Sweden)

    J. Beecken

    2014-10-01

    Full Text Available Emission factors of SO2, NOx and size distributed particle numbers were measured for approximately 300 different ships in the Gulf of Finland and Neva Bay area during two campaigns in August/September 2011 and June/July 2012. The measurements were carried out from a harbor vessel and from an MI-8 helicopter downwind of passing ships. Other measurements were carried out from shore sites near the island of Kronstadt and along the river Neva in the city area of Saint Petersburg. Most ships were running at reduced speed (10 knots, i.e. not at their optimal load. Vessels for domestic and international shipping were monitored. It was seen that the distribution of the SO2 emission factors is bi-modal with averages of 4.6 gSO2 kgfuel−1 and 18.2 gSO2 kgfuel−1 for the lower and the higher mode, respectively. The emission factors show compliance with the 1% fuel sulfur content SECA limit for 90% of the vessels in 2011 and 97% in 2012. The distribution of the NOx emission factor is mono-modal with an average of 58 gNOx kgfuel−1. The corresponding emission related to the generated power yields an average of 12.1 gNOx kWh−1. The distribution of the emission factors for particulate number shows that nearly 90% of all particles in the 5.6 nm to 10 μm size range were below 70 nm in diameter. The distribution of the corresponding emission factors for the mass indicates two separated main modes, one for particles between 30 and 300 nm the other above 2 μm. The average particle emission factors were found to be in the range from 0.7 to 2.7 × 1016 particles kgfuel−1 and 0.2 to 3.4 gPM kgfuel−1, respectively. The NOx and particulate emissions are comparable with other studies. The measured emission factors were compared, for individual ships, to modeled ones using the Ship Traffic Emission Assessment Model (STEAM of the Finnish Meteorological Institute. A reasonably good agreement for gaseous sulfur and nitrogen emissions can be seen for ships in

  8. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    David R. Thompson; Lawrence E. Bool; Jack C. Chen

    2004-04-01

    Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this

  9. Modeling of battery energy storage in the National Energy Modeling System

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, S.; Flynn, W.T.; Sen, R.K. [Sentech, Inc., Bethesda, MD (United States)

    1997-12-01

    The National Energy Modeling System (NEMS) developed by the U.S. Department of Energy`s Energy Information Administration is a well-recognized model that is used to project the potential impact of new electric generation technologies. The NEMS model does not presently have the capability to model energy storage on the national grid. The scope of this study was to assess the feasibility of, and make recommendations for, the modeling of battery energy storage systems in the Electricity Market of the NEMS. Incorporating storage within the NEMS will allow the national benefits of storage technologies to be evaluated.

  10. Modeling of battery energy storage in the National Energy Modeling System

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, S.; Flynn, W.T.; Sen, R.K. [Sentech, Inc., Bethesda, MD (United States)

    1997-12-01

    The National Energy Modeling System (NEMS) developed by the U.S. Department of Energy`s Energy Information Administration is a well-recognized model that is used to project the potential impact of new electric generation technologies. The NEMS model does not presently have the capability to model energy storage on the national grid. The scope of this study was to assess the feasibility of, and make recommendations for, the modeling of battery energy storage systems in the Electricity Market of the NEMS. Incorporating storage within the NEMS will allow the national benefits of storage technologies to be evaluated.

  11. Exact solutions for the spin tune for model storage rings

    CERN Document Server

    Mane, S R

    2002-01-01

    We present exact analytical expressions for the spin tune for arbitrary values of the orbital action for several storage ring models. The models we treat contain Siberian Snakes, the use of which is essential to preserve the polarization of beams in high-energy proton storage rings. Our solutions contain some novel features. We also prove a previously conjectured claim about the behavior of spin tuneshifts in rings with multiple Snakes. The conjecture is based on numerical simulations, but our proof is analytical, and also nonperturbative.

  12. Sulfur Management of NOx Adsorber Technology for Diesel Light-Duty Vehicle and Truck Applications

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Howard L.; Wang, Jerry C.; Yu, Robert C. (Cummins, Inc.); Wan, C. Z. (Engelhard Corp.); Howden, Ken (U.S. Dept. of Energy)

    2003-10-01

    Sulfur poisoning from engine fuel and lube is one of the most recognizable degradation mechanisms of a NOx adsorber catalyst system for diesel emission reduction. Even with the availability of 15 ppm sulfur diesel fuel, NOx adsorber will be deactivated without an effective sulfur management. Two general pathways are currently being explored for sulfur management: (1) the use of a disposable SOx trap that can be replaced or rejuvenated offline periodically, and (2) the use of diesel fuel injection in the exhaust and high temperature de-sulfation approach to remove the sulfur poisons to recover the NOx trapping efficiency. The major concern of the de-sulfation process is the many prolonged high temperature rich cycles that catalyst will encounter during its useful life. It is shown that NOx adsorber catalyst suffers some loss of its trapping capacity upon high temperature lean-rich exposure. With the use of a disposable SOx trap to remove large portion of the sulfur poisons from the exhaust, the NOx adsorber catalyst can be protected and the numbers of de-sulfation events can be greatly reduced. Spectroscopic techniques, such as DRIFTS and Raman, have been used to monitor the underlying chemical reactions during NOx trapping/ regeneration and de-sulfation periods, and provide a fundamental understanding of NOx storage capacity and catalyst degradation mechanism using model catalysts. This paper examines the sulfur effect on two model NOx adsorber catalysts. The chemistry of SOx/base metal oxides and the sulfation product pathways and their corresponding spectroscopic data are discussed. SAE Paper SAE-2003-01-3245 {copyright} 2003 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed

  13. A Novel Dynamic Physical Storage Model for Vehicle Navigation Maps

    Directory of Open Access Journals (Sweden)

    Shaohua Wang

    2016-04-01

    Full Text Available The physical storage model is one of the key technologies for vehicle navigation maps used in a navigation system. However, the performance of most traditional storage models is limited in dynamic navigation due to the static storage format they use. In this paper, we proposed a new physical storage model, China Navigation Data Format (CNDF, which helped access and update the navigation data. The CNDF model used the reach-based hierarchy method to build a road hierarchal network, which enhanced the efficiency of data compression. It also adopted the Linear Link Coding method, in which the start position was combined with the end position as the identification code for multi-level links, and each link traced up-level links consistently without recording the array of identifications. The navigation map of East China (including Beijing, Tianjin, Shandong, Hebei, and Jiangsu at 1:10,000, generated using the CNDF model, and the real time traffic information in Beijing were combined to test the performance of a navigation system using an embedded navigation device. Results showed that it cost less than 1 second each time to refresh the navigation map, and the accuracy of the hierarchal shortest-path algorithm was 99.9%. Our work implied that the CNDF model is efficient in vehicle navigation applications.

  14. Key management and encryption under the bounded storage model.

    Energy Technology Data Exchange (ETDEWEB)

    Draelos, Timothy John; Neumann, William Douglas; Lanzone, Andrew J.; Anderson, William Erik

    2005-11-01

    There are several engineering obstacles that need to be solved before key management and encryption under the bounded storage model can be realized. One of the critical obstacles hindering its adoption is the construction of a scheme that achieves reliable communication in the event that timing synchronization errors occur. One of the main accomplishments of this project was the development of a new scheme that solves this problem. We show in general that there exist message encoding techniques under the bounded storage model that provide an arbitrarily small probability of transmission error. We compute the maximum capacity of this channel using the unsynchronized key-expansion as side-channel information at the decoder and provide tight lower bounds for a particular class of key-expansion functions that are pseudo-invariant to timing errors. Using our results in combination with Dziembowski et al. [11] encryption scheme we can construct a scheme that solves the timing synchronization error problem. In addition to this work we conducted a detailed case study of current and future storage technologies. We analyzed the cost, capacity, and storage data rate of various technologies, so that precise security parameters can be developed for bounded storage encryption schemes. This will provide an invaluable tool for developing these schemes in practice.

  15. Functions and regulation of the Nox family in the filamentous fungus Podospora anserina: a new role in cellulose degradation.

    Science.gov (United States)

    Brun, Sylvain; Malagnac, Fabienne; Bidard, Frédérique; Lalucque, Hervé; Silar, Philippe

    2009-10-01

    NADPH oxidases are enzymes that produce reactive oxygen species. Studies in mammals, plants and fungi have shown that they play important roles in differentiation, defence, host/pathogen interaction and mutualistic symbiosis. In this paper, we have identified a Podospora anserina mutant strain impaired for processes controlled by PaNox1 and PaNox2, the two Nox isoforms characterized in this model ascomycete. We show that the gene mutated is PaNoxR, the homologue of the gene encoding the regulatory subunit p67(phox), conserved in mammals and fungi, and that PaNoxR regulates both PaNox1 and PaNox2. Genome sequence analysis of P. anserina reveals that this fungus posses a third Nox isoform, PaNox3, related to human Nox5/Duox and plant Rboh. We have generated a knock-out mutant of PaNox3 and report that PaNox3 plays a minor role in P. anserina, if any. We show that PaNox1 and PaNox2 play antagonist roles in cellulose degradation. Finally, we report for the first time that a saprobic fungus, P. anserina, develops special cell structures dedicated to breach and to exploit a solid cellulosic substrate, cellophane. Importantly, as for similar structures present in some plant pathogens, their proper differentiation requires PaNox1, PaNox2, PaNoxR and the tetraspanin PaPls1.

  16. Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials

    Directory of Open Access Journals (Sweden)

    Ganesh Chandra Dhal

    2017-04-01

    Full Text Available In this research paper, the nanometric size effect, the effects of the intrinsic factors including structure, and the redox properties of three systems of nanometric of silver-based catalysts were summarized. In this work, these catalysts were investigated for the simultaneous removal of particulate matter (diesel soot, and NOX was compared with that of a model of Pt-Ba/Al2O3 catalyst. The Silver-Barium based catalytic materials of Ag (5 wt%-Ba(10 wt%/MO (MO=Al2O3, CeO2, ZrO2, and Ag (5 wt%-Sr (10 wt%/CeO2 catalysts have been prepared by wetness impregnation method and characterized by BET, XRD, HRTEM, XPS and TPR (temperature-programmed reduction experiments. The behavior of the catalyst in the soot combustion (under tight conditions and NOX elimination has been separately analyzed by means of temperature programmed oxidation and isothermal concentration step change experiments, respectively. The results showed that all the catalysts were active in soot combustion with an indicative decrease of oxidation onset temperature compared to uncatalyzed soot oxidation. The removal of NOX in the presence and in the absence of soot was investigated under cycling conditions, i.e. alternating lean-rich phases according to the LNT approach. It has been found that the Ag-based samples were able to simultaneously remove soot and NOX. In particular, studying the behavior of the prepared catalysts, the Ba-containing systems exhibited higher NOX storage capacity than Sr-catalyst; also, the nitrogen selectivity increased even if resulted lower than the traditional LNT Pt-based catalyst. An adverse effect of soot on the NOX storage activity has been also observed. Copyright © 2017 BCREC GROUP. All rights reserved Received: 18th August 2016; Revised: 19th October 2016; Accepted: 19th October 2016 How to Cite: Dhal, G.C., Dey, S., Prasad, R., Mohan, D. (2017. Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials. Bulletin of

  17. Advances in catalytic removal of NOx under lean-burn conditions

    Institute of Scientific and Technical Information of China (English)

    LIU Zhiming; HAO Jiming; FU Lixin; LI Junhua; CUI Xiangyu

    2004-01-01

    The catalytic removal of NOx under lean conditions is one of the most important targets in catalysis research. The activities of metal oxides, zeolite-based catalysts and noble metal catalysts together with the factors are influencing the selective reduction of NOx with hydrocarbons are reviewed. The reaction mechanisms for the three types of catalysts are briefly discussed. Recent progress in combined catalyst and NOx storage reduction catalysts is also introduced. Finally, future research directions are forecasted.

  18. System-level modeling for geological storage of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingqi; Oldenburg, Curtis M.; Finsterle, Stefan; Bodvarsson, Gudmundur S.

    2006-04-24

    One way to reduce the effects of anthropogenic greenhousegases on climate is to inject carbon dioxide (CO2) from industrialsources into deep geological formations such as brine formations ordepleted oil or gas reservoirs. Research has and is being conducted toimprove understanding of factors affecting particular aspects ofgeological CO2 storage, such as performance, capacity, and health, safetyand environmental (HSE) issues, as well as to lower the cost of CO2capture and related processes. However, there has been less emphasis todate on system-level analyses of geological CO2 storage that considergeological, economic, and environmental issues by linking detailedrepresentations of engineering components and associated economic models.The objective of this study is to develop a system-level model forgeological CO2 storage, including CO2 capture and separation,compression, pipeline transportation to the storage site, and CO2injection. Within our system model we are incorporating detailedreservoir simulations of CO2 injection and potential leakage withassociated HSE effects. The platform of the system-level modelingisGoldSim [GoldSim, 2006]. The application of the system model is focusedon evaluating the feasibility of carbon sequestration with enhanced gasrecovery (CSEGR) in the Rio Vista region of California. The reservoirsimulations are performed using a special module of the TOUGH2 simulator,EOS7C, for multicomponent gas mixtures of methane and CO2 or methane andnitrogen. Using this approach, the economic benefits of enhanced gasrecovery can be directly weighed against the costs, risks, and benefitsof CO2 injection.

  19. Radiolysis Model Sensitivity Analysis for a Used Fuel Storage Canister

    Energy Technology Data Exchange (ETDEWEB)

    Wittman, Richard S.

    2013-09-20

    This report fulfills the M3 milestone (M3FT-13PN0810027) to report on a radiolysis computer model analysis that estimates the generation of radiolytic products for a storage canister. The analysis considers radiolysis outside storage canister walls and within the canister fill gas over a possible 300-year lifetime. Previous work relied on estimates based directly on a water radiolysis G-value. This work also includes that effect with the addition of coupled kinetics for 111 reactions for 40 gas species to account for radiolytic-induced chemistry, which includes water recombination and reactions with air.

  20. Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2013-04-01

    Full Text Available An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT for NOx storage catalysts (NSC enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380 °C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD. The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1 time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2 during the short-term thermal NOx release.

  1. Factors Affecting the Relative Success of EPA’s NOx CAP-and-Trade Program.

    Science.gov (United States)

    1998-06-01

    concerns as the use of banked NOx allowances. 27. See Laurel J. Carlson, NESCAUM/ MARAMA NOx Budget Model Rule (prepared for the Northeast States for...Coordinated Air Use Management (NESCAUM) and the Mid-Atlantic Regional Air Management Association ( MARAMA ) NO, Budget Task Force’s NESCAUM/ MARAMA NOx...a two-for-one basis. See Laurel J. Carlson, NESCA UM/ MARAMA NOxBudget Model Rule (prepared for the Northeast States for Coordinated Air Use

  2. New simulation model of absorption pump with internal storage

    Energy Technology Data Exchange (ETDEWEB)

    San Juan, Cristina; Soutullo, Silvia; Enriquez, Ricardo; Ferrer, Jose Antonio; Heras, M Rosario [Energy Efficiency in Buildings R and D Unit. CIEMAT., Avenida Complutense 22, 28040 Madrid, (Spain)], email: cristina.sanjuan@ciemat.es

    2010-07-01

    In hot climates, such as in Spain, conditioning systems are used to provide a good level of thermal comfort during summer. Systems are usually composed of one liquid absorption pump and external storage in a water tank. The aim of this study is to present a new technology whereby energy is stored in crystallized salts through the use of 4 heat pumps. A case study was carried out in the Plataforma Solar de Almeria, Spain, where the performance of both conventional and new cooling systems were analyzed through the use of a dynamic model in TRNSYS. Results showed that for the new system, adaptability increases with the number of independent blocks and its performance is influenced by the control strategy. In addition it was found that 15m3 of external storage are required in conventional systems to achieve the same performance as the new system. This study showed that the new system requires less storage room than conventional systems.

  3. Quantifying watershed surface depression storage: determination and application in a hydrologic model

    Science.gov (United States)

    Joseph K. O. Amoah; Devendra M. Amatya; Soronnadi. Nnaji

    2012-01-01

    Hydrologic models often require correct estimates of surface macro-depressional storage to accurately simulate rainfall–runoff processes. Traditionally, depression storage is determined through model calibration or lumped with soil storage components or on an ad hoc basis. This paper investigates a holistic approach for estimating surface depressional storage capacity...

  4. Optimum NOx abatement in diesel exhaust using inferential feedforward reductant control

    Energy Technology Data Exchange (ETDEWEB)

    Krijnsen, H.C.; Leeuwen, J.C.M. van; Bakker, R.; Bleek, C.M. van den; Calis, H.P.A. [Delft University of Technology, Delft (Netherlands). DelftChem Tech, Faculty of Applied Sciences, Chemical Reactor Engineering

    2001-05-01

    To adequately control the reductant flow for the selective catalytic reduction of NOx in diesel exhaust gas a tool is required that is capable of accurately and quickly predicting the engine's fluctuating NOx emissions based on its time-dependent operating variables, and that is also capable of predicting the optimum reductant/NOx ratio for NOx abatement. Measurements were carried out on a semi-stationary diesel engine. Four algorithms for non-linear modelling are evaluated. The models resulting from the algorithms gave very accurate NOx predictions with a short computation time. Together with the small errors this makes the models very promising tools for on-line automotive NOx emission control. The optimum reductant/NOx ratio (to get the lowest combined NOx + reduction emission of the exhaust treating system) was best predicted by a neural network. 24 refs., 6 figs., 5 tabs.

  5. Single bank NOx adsorber for heavy duty diesel engines

    NARCIS (Netherlands)

    Genderen, M. van; Aken, M.G. van

    2003-01-01

    In a NOx adsorber programme the feasibility for applying this technology to heavy duty diesel engines was investigated. After modelling and simulations for realising best λ < 1 engine conditions a platform was build which was used to obtain good NOx adsorber regeneration settings in a number of stea

  6. Design of Dimensional Model for Clinical Data Storage and Analysis

    Directory of Open Access Journals (Sweden)

    Dipankar SENGUPTA

    2013-06-01

    Full Text Available Current research in the field of Life and Medical Sciences is generating chunk of data on daily basis. It has thus become a necessity to find solutions for efficient storage of this data, trying to correlate and extract knowledge from it. Clinical data generated in Hospitals, Clinics & Diagnostics centers is falling under a similar paradigm. Patient’s records in various hospitals are increasing at an exponential rate, thus adding to the problem of data management and storage. Major problem being faced corresponding to storage, is the varied dimensionality of the data, ranging from images to numerical form. Therefore there is a need for development of efficient data model which can handle this multi-dimensionality data issue and store the data with historical aspect.For the stated problem lying in façade of clinical informatics we propose a clinical dimensional model design which can be used for development of a clinical data mart. The model has been designed keeping in consideration temporal storage of patient's data with respect to all possible clinical parameters which can include both textual and image based data. Availability of said data for each patient can be then used for application of data mining techniques for finding the correlation of all the parameters at the level of individual and population.

  7. Induced pluripotent stem cell models of lysosomal storage disorders

    Directory of Open Access Journals (Sweden)

    Daniel K. Borger

    2017-06-01

    Full Text Available Induced pluripotent stem cells (iPSCs have provided new opportunities to explore the cell biology and pathophysiology of human diseases, and the lysosomal storage disorder research community has been quick to adopt this technology. Patient-derived iPSC models have been generated for a number of lysosomal storage disorders, including Gaucher disease, Pompe disease, Fabry disease, metachromatic leukodystrophy, the neuronal ceroid lipofuscinoses, Niemann-Pick types A and C1, and several of the mucopolysaccharidoses. Here, we review the strategies employed for reprogramming and differentiation, as well as insights into disease etiology gleaned from the currently available models. Examples are provided to illustrate how iPSC-derived models can be employed to develop new therapeutic strategies for these disorders. We also discuss how models of these rare diseases could contribute to an enhanced understanding of more common neurodegenerative disorders such as Parkinson’s disease, and discuss key challenges and opportunities in this area of research.

  8. Impact of Soot on NOx Adsorption over Cu-Modified Hydrotalcite-Derived Lean NOx Trap Catalyst.

    Science.gov (United States)

    Li, Bo; Song, Chonglin; Lv, Gang; Chen, Ke; Cao, Xiaofeng

    2017-03-28

    The impact of soot on NOx adsorption was studied over a Cu-modified hydrotalcite-derived lean NOx trap catalyst in a NO + O2 atmosphere. Powder X-ray diffraction, scanning electron microscopy, Raman scattering spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the surface properties of the pure catalyst and the soot/catalyst mixture. The adsorbed NOx species on the samples were evaluated by in situ diffuse reflectance Fourier transform spectroscopy. The soot coverage decreases the available adsorption sites on the surface of the catalyst, and a portion of active oxygen species are consumed by the soot oxidation during He pretreatment process. The NOx adsorption on two catalyst samples simultaneously undergoes two routes: the "nitrite route" and the "nitrate route". The "nitrite route" is more dominant than the "nitrate route". During NOx adsorption, the soot oxidation weakens the NO oxidation to NO2, and the released CO2 competes with NOx on the adsorption sites. Moreover, the temperature-programmed desorption tests indicate that the presence of soot reduces the NOx storage capacity of the catalyst and shifts the NO desorption peak to the lower temperature range by 50 °C.

  9. 基于果蝇优化算法的锅炉高效率低N Ox 燃烧建模%Fruit fly optimization algorithm based high efficiency and low NOx combustion modeling for a boiler

    Institute of Scientific and Technical Information of China (English)

    张振星; 孙保民; 信晶

    2014-01-01

    In order to control NOx emissions and enhance boiler efficiency in coal-fired boilers,the thermal operating data from an ultra-supercritical 1000MW unit boiler were analyzed.On the basis of the support vector regression machine (SVM),the fruit fly optimization algorithm (FOA)was applied to optimize the penalty parameter C,kernel parameter g and insensitive loss coefficient of the model.Then,the FOA-SVM model was established to predict the NOx emissions and boiler efficiency,and the performance of this model was compared with that of the GA-SVM model optimized by genetic algorithm (GA).The results show the FOA-SVM model has better prediction accuracy and generalization capability,of which the maximum aver-age relative error of testing set lies in the NOx emissions model,which is only 3 .5 9%.The above models can predict the NOx emissions and boiler efficiency accurately,so they are very suitable for on-line modeling prediction,which provides a good model foundation for further optimization operation of large capacity boilers.%为了控制燃煤锅炉的NOx 排放量并提高锅炉效率,对某超超临界1000 MW机组锅炉的热态运行数据进行分析,基于支持向量回归机(SVM),建立了 NOx 排放和锅炉热效率的 FOA-SVM模型,采用果蝇优化算法(FOA)对模型中的惩罚因子C、核函数参数g和不敏感损失系数ε这3个参数寻优,并与遗传算法(GA)优化参数的预测模型进行比较.结果表明,FOA-SVM模型的预测精度更高,泛化能力更强,其中误差最大的 NOx 排放模型测试集数据的平均相对误差仅3.59%,能够精准地预测锅炉热效率和 N Ox 排放,适合于在线建模预测,为大容量锅炉的进一步优化运行提供了良好的模型基础.

  10. Packed bed heat storage: Continuum mechanics model and validation

    Science.gov (United States)

    Knödler, Philipp; Dreißigacker, Volker; Zunft, Stefan

    2016-05-01

    Thermal energy storage (TES) systems are key elements for various types of new power plant concepts. As possible cost-effective storage inventory option, packed beds of miscellaneous material come into consideration. However, high technical risks arise due to thermal expansion and shrinking of the packed bed's particles during cyclic thermal operation, possibly leading to material failure. Therefore, suitable tools for designing the heat storage system are mandatory. While particle discrete models offer detailed simulation results, the computing time for large scale applications is inefficient. In contrast, continuous models offer time-efficient simulation results but are in need of effective packed bed parameters. This work focuses on providing insight into some basic methods and tools on how to obtain such parameters and on how they are implemented into a continuum model. In this context, a particle discrete model as well as a test rig for carrying out uniaxial compression tests (UCT) is introduced. Performing of experimental validation tests indicate good agreement with simulated UCT results. In this process, effective parameters required for a continuous packed bed model were identified and used for continuum simulation. This approach is validated by comparing the simulated results with experimental data from another test rig. The presented method significantly simplifies subsequent design studies.

  11. Impacts of contaminant storage on indoor air quality: Model development

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max H.; Hult, Erin L.

    2013-02-26

    A first-order, lumped capacitance model is used to describe the buffering of airborne chemical species by building materials and furnishings in the indoor environment. The model is applied to describe the interaction between formaldehyde in building materials and the concentration of the species in the indoor air. Storage buffering can decrease the effect of ventilation on the indoor concentration, compared to the inverse dependence of indoor concentration on the air exchange rate that is consistent with a constant emission rate source. If the exposure time of an occupant is long relative to the time scale of depletion of the compound from the storage medium, however, the total exposure will depend inversely on the air exchange rate. This lumped capacitance model is also applied to moisture buffering in the indoor environment, which occurs over much shorter depletion timescales of the order of days. This model provides a framework to interpret the impact of storage buffering on time-varying concentrations of chemical species and resulting occupant exposure. Pseudo-steady state behavior is validated using field measurements. Model behavior over longer times is consistent with formaldehyde and moisture concentration measurements in previous studies.

  12. An Investigation of the Kinematic and Microphysical Control of Lightning Rate, Extent and NOx Production using DC3 Observations and the NASA Lightning Nitrogen Oxides Model (LNOM)

    Science.gov (United States)

    Carey, Lawrence; Koshak, William; Peterson, Harold; Matthee, Retha; Bain, Lamont

    2013-01-01

    The Deep Convective Clouds and Chemistry (DC3) experiment seeks to quantify the relationship between storm physics, lightning characteristics and the production of nitrogen oxides via lightning (LNOx). The focus of this study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern LNOx production, such as flash rate, type and extent across Alabama during DC3. Prior studies have demonstrated that lightning flash rate and type is correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume and graupel mass. More study is required to generalize these relationships in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm physics, morphology and three-dimensional flash extent, despite its importance for LNOx production. To address this conceptual gap, the NASA Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection Network(TM) (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash rate, flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to multicell thunderstorms over Northern Alabama on two days during DC3 (21 May and 11 June 2012) in which aircraft observations of NOx are available for comparison. The LNOM lightning characteristics and LNOX production estimates are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby radar network, including the UAH Advanced Radar for Meteorological and Operational Research (ARMOR). Given complex multicell evolution, particular attention is paid to storm morphology, cell

  13. FACSIM/MRS (Monitored Retrievable Storage)-2: Storage and shipping model documentation and user's guide

    Energy Technology Data Exchange (ETDEWEB)

    Huber, H.D.; Chockie, A.D.; Hostick, C.J.; Otis, P.T.; Sovers, R.A.

    1987-06-01

    The Pacific Northwest Laboratory (PNL) has developed a stochastic computer model, FACSIM/MRS, to assist in assessing the operational performance of the Monitored Retrievable Storage (MRS) waste-handling facility. This report provides the documentation and user's guide for FACSIM/MRS-2, which is also referred to as the back-end model. The FACSIM/MRS-2 model simulates the MRS storage and shipping operations, which include handling canistered spent fuel and secondary waste in the shielded canyon cells, in onsite yard storage, and in repository shipping cask loading areas.

  14. Enhanced Combustion Low NOx Pulverized Coal Burner

    Energy Technology Data Exchange (ETDEWEB)

    David Towle; Richard Donais; Todd Hellewell; Robert Lewis; Robert Schrecengost

    2007-06-30

    economic evaluation and commercial application. During the project performance period, Alstom performed computational fluid dynamics (CFD) modeling and large pilot scale combustion testing in its Industrial Scale Burner Facility (ISBF) at its U.S. Power Plant Laboratories facility in Windsor, Connecticut in support of these objectives. The NOx reduction approach was to optimize near-field combustion to ensure that minimum NOx emissions are achieved with minimal impact on unburned carbon in ash, slagging and fouling, corrosion, and flame stability/turn-down. Several iterations of CFD and combustion testing on a Midwest coal led to an optimized design, which was extensively combustion tested on a range of coals. The data from these tests were then used to validate system costs and benefits versus SCR. Three coals were evaluated during the bench-scale and large pilot-scale testing tasks. The three coals ranged from a very reactive subbituminous coal to a moderately reactive Western bituminous coal to a much less reactive Midwest bituminous coal. Bench-scale testing was comprised of standard ASTM properties evaluation, plus more detailed characterization of fuel properties through drop tube furnace testing and thermogravimetric analysis. Bench-scale characterization of the three test coals showed that both NOx emissions and combustion performance are a strong function of coal properties. The more reactive coals evolved more of their fuel bound nitrogen in the substoichiometric main burner zone than less reactive coal, resulting in the potential for lower NOx emissions. From a combustion point of view, the more reactive coals also showed lower carbon in ash and CO values than the less reactive coal at any given main burner zone stoichiometry. According to bench-scale results, the subbituminous coal was found to be the most amenable to both low NOx, and acceptably low combustibles in the flue gas, in an air staged low NOx system. The Midwest bituminous coal, by contrast, was

  15. Distributed Data Storage Model for Cattle Health Monitoring Using WSN

    Directory of Open Access Journals (Sweden)

    Ankit R. Bhavsar

    2013-05-01

    Full Text Available Now a day, wireless sensor networks (WSN are being deployed in various applications like industrial, environmental, health care, societal monitoring. The sensor networks have tendency to generate huge amount of data. Hence data storage techniques become a critical issue for the success of these applications. In this paper, we have proposed a distributed data storage model used for WSN based cattle health monitoring. We have also defined the structure for the same. We have divided this model into two levels namely a local level and a central level. The main aim of storing data locally is to get quick response for any query raised by the user. The second level where the data is centralized is used to make long term decision, planning and policy for the cattle health monitoring.

  16. Mechanistic Investigation of the Reduction of NOx over Pt- and Rh-Based LNT Catalysts

    Directory of Open Access Journals (Sweden)

    Lukasz Kubiak

    2016-03-01

    Full Text Available The influence of the noble metals (Pt vs. Rh on the NOx storage reduction performances of lean NOx trap catalysts is here investigated by transient micro-reactor flow experiments. The study indicates a different behavior during the storage in that the Rh-based catalyst showed higher storage capacity at high temperature as compared to the Pt-containing sample, while the opposite is seen at low temperatures. It is suggested that the higher storage capacity of the Rh-containing sample at high temperature is related to the higher dispersion of Rh as compared to Pt, while the lower storage capacity of Rh-Ba/Al2O3 at low temperature is related to its poor oxidizing properties. The noble metals also affect the catalyst behavior upon reduction of the stored NOx, by decreasing the threshold temperature for the reduction of the stored NOx. The Pt-based catalyst promotes the reduction of the adsorbed NOx at lower temperatures if compared to the Rh-containing sample, due to its superior reducibility. However, Rh-based material shows higher reactivity in the NH3 decomposition significantly enhancing N2 selectivity. Moreover, formation of small amounts of N2O is observed on both Pt- and Rh-based catalyst samples only during the reduction of highly reactive NOx stored at 150 °C, where NOx is likely in the form of nitrites.

  17. Constraining NOx emissions over East Asia using satellite NO2 column retrievals with emphasis on the role of NOx transport

    Science.gov (United States)

    Lee, H.; Kim, S.; Brioude, J. F.; Cooper, O. R.; Frost, G. J.; Kim, C.; Trainer, M.

    2013-12-01

    Satellite observations have provided a continuous view of significant changes in NOx emissions over the past two decades. In this study, tropospheric NO2 columns from the polar orbiting OMI, SCIAMACHY and GOME-2 instruments were used to diagnose the annual and seasonal variations and the spatial characteristic of NOx emissions over East Asia. As expected, we found substantial increases in both NO2 columns and bottom-up NOx emissions over China from 2005 to 2011, resulting from rapid economic growth. However, the year-to-year change in NO2 columns over Korea showed increasing trends, in contrast to decreasing inventoried NOx emissions. Both NO2 columns and bottom-up NOx emissions over Japan decreased during this period. Seasonally, maximum and minimum NO2 columns occur in winter and summer above China, Korea, and Japan, as NOx chemical lifetime changes. Above Korea and Japan, however, secondary peaks are found in spring. Numerical simulations using Lagrangian and Eulerian chemical transport models indicate that transport of NOx from China could explain the spring peaks of NO2 columns above Korea and Japan and the discrepancy between annual trends of satellite observations and bottom-up emissions downwind of China . The model results also quantify the contributions of emissions and transport to the local NOx budget over each country and sub-regions of China.

  18. Expression of NADPH oxidase (NOX 5 in rabbit corneal stromal cells.

    Directory of Open Access Journals (Sweden)

    Farhan Rizvi

    Full Text Available PURPOSE: To determine whether NOX 5 is expressed in rabbit corneal stromal cells (RCSC. NADPH oxidases (NOXes are enzymes that preferentially use NADPH as a substrate and generate superoxide. Several isoforms of NOXes function as multi-protein complexes while NOX5 and DUOXs do not require the accessory proteins for their activity and possess calcium binding EF hands. METHODS: Human NOX5 primers were used to amplify the rabbit NOX5 by RT-PCR. Amplified product was sequenced to confirm its identity. The protein encoded by the NOX5 was identified by western blot analysis. NOX5 siRNA was used to reduce transcript, protein, and calcium stimulated activity. In silico analyses were performed to establish the putative structure, functions, and evolution of rabbit NOX5. RESULTS: NOX activity was measured in RCSC with NADPH rather than NADH as a substrate. RT-PCR with NOX5 primers amplified 288 bp product using RCSC cDNA, which, when sequenced, confirmed its identity to human NOX5 mRNA. This sequence was used to predict the rabbit (Oryctolagus cuniculus NOX5 gene. NOX5 siRNA reduced amounts of NOX5 mRNA in RCSC and reduced ionomycin stimulated superoxide production. A protein of about 65 to 70 kDa encoded by the NOX5 was detected by western blot analysis. In silico analysis predicted a putative rabbit NOX5 protein containing 801 amino acids. Motif searches predicted the presence of at least 3 putative EF-hands in N-terminus and a NOX domain in C terminal region. CONCLUSIONS: The data document that the NOX5 gene was expressed in cells of lagomorphs unlike rodents, making the rabbit an interesting model to study NOX5 functions. The activity of the rabbit NOX5 was calcium stimulated, a trait of NOX5 in general. NOX5 may also prove to be a useful genetic marker for studying the taxonomic position of lagomorphs and the Glires classification.

  19. Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts

    Science.gov (United States)

    Brioude, Jerome; Angevine, Wayne; Ahmadov, Ravan; Kim, Si Wan; Evan, Stephanie; McKeen, Stuart; Hsie, Eirh Yu; Frost, Greg; Neuman, Andy; Pollack, Ilana; Peischl, Jeff; Ryerson, Tom; Holloway, John; Brown, Steeve; Nowak, John; Roberts, Jim; Wofsy, Steeve; Santoni, Greg; Trainer, Michael

    2013-04-01

    We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May-June 2010. The US EPA National Emission Inventory 2005 (NEI 2005) was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was used to calculate the CO2 inventory without prior knowledge of CO2 surface fluxes. The inversion was applied to each flight to estimate the variability of single-flight-based flux estimates. In Los Angeles (LA) County, the uncertainties on CO and NOx fluxes were 10% and 15%, respectively. Compared with NEI 2005, the CO posterior emissions were lower by 43% ± 6% in LA County and by 37% ± 10% in the South Coast Air Basin (SoCAB). NOx posterior emissions were lower by 32% ± 10% in LA County and by 27% ± 15% in the SoCAB. NOx posterior emissions were 40% lower on weekends relative to weekdays. The CO2 posterior estimates were 183 ± 18 Tg yr-1 in SoCAB. A flight during ITCT in 2002 was used to estimate emissions in the LA Basin in 2002. From 2002 to 2010, the CO and NOx posterior emissions decreased by 41% and 37%, respectively, in agreement with previous studies. Over the same time period, CO2 emissions increased by 10% ± 14% in LA County but decreased by 4% ± 10% in the SoCAB, a statistically insignificant change. Overall, the posterior estimates were in good agreement with the California Air Resources Board (CARB) inventory, with differences of 15% or less. However, the posterior spatial distribution in the basin was significantly different from CARB for NOx emissions. WRF-Chem mesoscale chemical-transport model simulations allowed an evaluation of differences in chemistry using different inventory assumptions, including NEI 2005, CARB 2010 and the posterior inventories derived in

  20. Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts

    Directory of Open Access Journals (Sweden)

    S. C. Wofsy

    2012-12-01

    Full Text Available We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May–June 2010. The US EPA National Emission Inventory 2005 (NEI 2005 was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was used to calculate the CO2 inventory without prior knowledge of CO2 surface fluxes. The inversion was applied to each flight to estimate the variability of single-flight-based flux estimates. In Los Angeles (LA County, the uncertainties on CO and NOx fluxes were 10% and 15%, respectively. Compared with NEI 2005, the CO posterior emissions were lower by 43% ± 6% in LA County and by 37% ± 10% in the South Coast Air Basin (SoCAB. NOx posterior emissions were lower by 32% ± 10% in LA County and by 27% ± 15% in the SoCAB. NOx posterior emissions were 40% lower on weekends relative to weekdays. The CO2 posterior estimates were 183 ± 18 Tg yr−1 in SoCAB. A flight during ITCT in 2002 was used to estimate emissions in the LA Basin in 2002. From 2002 to 2010, the CO and NOx posterior emissions decreased by 41% and 37%, respectively, in agreement with previous studies. Over the same time period, CO2 emissions increased by 10% ± 14% in LA County but decreased by 4% ± 10% in the SoCAB, a statistically insignificant change. Overall, the posterior estimates were in good agreement with the California Air Resources Board (CARB inventory, with differences of 15% or less. However, the posterior spatial distribution in the basin was significantly different from CARB for NOx emissions. WRF-Chem mesoscale chemical-transport model simulations allowed an evaluation of differences in chemistry using different inventory assumptions, including NEI 2005, CARB 2010 and the posterior

  1. Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts

    Directory of Open Access Journals (Sweden)

    J. Brioude

    2013-04-01

    Full Text Available We present top-down estimates of anthropogenic CO, NOx and CO2 surface fluxes at mesoscale using a Lagrangian model in combination with three different WRF model configurations, driven by data from aircraft flights during the CALNEX campaign in southern California in May–June 2010. The US EPA National Emission Inventory 2005 (NEI 2005 was the prior in the CO and NOx inversion calculations. The flux ratio inversion method, based on linear relationships between chemical species, was used to calculate the CO2 inventory without prior knowledge of CO2 surface fluxes. The inversion was applied to each flight to estimate the variability of single-flight-based flux estimates. In Los Angeles (LA County, the uncertainties on CO and NOx fluxes were 10% and 15%, respectively. Compared with NEI 2005, the CO posterior emissions were lower by 43% in LA County and by 37% in the South Coast Air Basin (SoCAB. NOx posterior emissions were lower by 32% in LA County and by 27% in the SoCAB. NOx posterior emissions were 40% lower on weekends relative to weekdays. The CO2 posterior estimates were 183 Tg yr−1 in SoCAB. A flight during ITCT (Intercontinental Transport and Chemical Transformation in 2002 was used to estimate emissions in the LA Basin in 2002. From 2002 to 2010, the CO and NOx posterior emissions decreased by 41% and 37%, respectively, in agreement with previous studies. Over the same time period, CO2 emissions increased by 10% in LA County but decreased by 4% in the SoCAB, a statistically insignificant change. Overall, the posterior estimates were in good agreement with the California Air Resources Board (CARB inventory, with differences of 15% or less. However, the posterior spatial distribution in the basin was significantly different from CARB for NOx emissions. WRF-Chem mesoscale chemical-transport model simulations allowed an evaluation of differences in chemistry using different inventory assumptions, including NEI 2005, a gridded CARB

  2. MODELING OF HIGH STORAGE SHEET DEPOT WITH PLANT SIMULATION

    Directory of Open Access Journals (Sweden)

    Andrzej Jardzioch

    2013-03-01

    Full Text Available Manufacturing processes are becoming increasingly automated. Introduction of innovative solutions often necessitate processing very large number of signals from various devices. Correctness tests of the components configuration becomes a compiled operation requiring vast expenditure of time and knowledge. The models may be a mathematical reflection of the actual object. Many actions can be computer-assisted to varying degree. One example is construction of simulation models. These can also be simulation models developed in advanced software. The stages of creating a model may be purely random. This paper aims at a closer analysis of the simulation model based on the high storage sheet depot modeling using Plant Simulation software. The results of analysis can be used for optimization, but this stage is a separate issue.

  3. Improved storage efficiency through geologic modeling and reservoir simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ammer, J.R.; Mroz, T.H.; Covatch, G.L.

    1997-11-01

    The US Department of Energy (DOE), through partnerships with industry, is demonstrating the importance of geologic modeling and reservoir simulation for optimizing the development and operation of gas storage fields. The geologic modeling and reservoir simulation study for the Natural Fuel Gas Supply Corporation CRADA was completed in September 1995. The results of this study were presented at the 1995 Society of Petroleum Engineers` (SPE) Eastern Regional Meeting. Although there has been no field verification of the modeling results, the study has shown the potential advantages and cost savings opportunities of using horizontal wells for storage enhancement. The geologic modeling for the Equitrans` CRADA was completed in September 1995 and was also presented at the 1995 SPE Eastern Regional Meeting. The reservoir modeling of past field performance was completed in November 1996 and prediction runs are currently being made to investigate the potential of offering either a 10 day or 30 day peaking service in addition to the existing 110 day base load service. Initial results have shown that peaking services can be provided through remediation of well damage and by drilling either several new vertical wells or one new horizontal well. The geologic modeling for the Northern Indiana Public Service Company CRADA was completed in November 1996 with a horizontal well being completed in January 1997. Based on well test results, the well will significantly enhance gas deliverability from the field and will allow the utilization of gas from an area of the storage field that was not accessible from their existing vertical wells. Results are presented from these three case studies.

  4. A novel storage method for near infrared spectroscopy chemometric models.

    Science.gov (United States)

    Zhang, Zhi-Min; Chen, Shan; Liang, Yi-Zeng

    2010-06-04

    Chemometric Modeling Markup Language (CMML) is developed by us for containing chemometrics models within one document through converting binary data into strings by base64 encode/decode algorithms to solve the interoperability issue in sharing chemometrics models. It provides a base functionality for storage of sampling, variable selection, pretreating, outlier and modeling parameters and data. With the help of base64 algorithm, the usability of CMML is in equilibrium with size by transforming the binary data into base64 encoded string. Due to the advantages of Extensible Markup Language (XML), models stored in CMML can be easily reused in various other software and programming languages as long as the programming language has XML parsing library. One can also use the XML Path Language (XPath) query language to select desired data from the CMML file effectively. The application of this language in near infrared spectroscopy model storage is implemented as a class in C++ language and available as open source software (http://code.google.com/p/cmml), and the implementations in other languages, such as MATLAB and R are in progress.

  5. EMR modelling of a hydrogen-based electrical energy storage

    Science.gov (United States)

    Agbli, K. S.; Hissel, D.; Péra, M.-C.; Doumbia, I.

    2011-05-01

    This paper deals with multi-physics modelling of the stationary system. This modelling is the first step to reach the fuel cell system dimensioning aim pursued. Besides this modelling approach based on the stationary energetic system, the novelty in this paper is both the new approach of the photovoltaic EMR modelling and the EMR of the hydrogen storage process. The granular modelling approach is used to model each component of the system. Considering a stand alone PEM fuel cell system, hydrogen is expected to be produced and stored on the spot from renewable energy (photovoltaic) in order to satisfy the fuel availability. In fact, to develop a generic and modular model, energetic macroscopic representation (EMR) is used as graphical modelling tool. Allowing to be easily grasped by the experts even not necessarily gotten used to the modelling formalism, EMR is helpful to model the multi-domains energetic chain. The solar energy through solar module is converted in electrical energy; part of this energy is transformed in chemical energy (hydrogen) thanks to an electrolyser. Then the hydrogen is compressed into a tank across a storage system. The latter part of the solar module energy is stored as electrical energy within supercapacitor or lead-acid battery. Using the modularity feature of the EMR, the whole system is modelled entity by entity; afterwards by putting them together the overall system has been reconstructed. According to the scale effect of the system entities, some simulation and/or experimental results are given. Given to the different aims which are pursued in the sustainable energy framework like prediction, control and optimisation, EMR modelling approach is a reliable option for the energy management in real time of energetic system in macroscopic point of view.

  6. A Model of BES Data Storage Management System

    Institute of Scientific and Technical Information of China (English)

    MeiYE; MeiMA; 等

    2001-01-01

    In this article we will introduce the system structure of a model built for BES data management and storage as well as the basic methods on how to establish the system.Additionally the analysis of the data structure,the data process,the selection of experimental program,the image manipulation and the key techniques will be discussed in detail,The model implements the setup of the system environment and all those functions from data loading,database cresting,data accessing,remote data process to data figuring.

  7. On the Maximum Storage Capacity of the Hopfield Model

    Science.gov (United States)

    Folli, Viola; Leonetti, Marco; Ruocco, Giancarlo

    2017-01-01

    Recurrent neural networks (RNN) have traditionally been of great interest for their capacity to store memories. In past years, several works have been devoted to determine the maximum storage capacity of RNN, especially for the case of the Hopfield network, the most popular kind of RNN. Analyzing the thermodynamic limit of the statistical properties of the Hamiltonian corresponding to the Hopfield neural network, it has been shown in the literature that the retrieval errors diverge when the number of stored memory patterns (P) exceeds a fraction (≈ 14%) of the network size N. In this paper, we study the storage performance of a generalized Hopfield model, where the diagonal elements of the connection matrix are allowed to be different from zero. We investigate this model at finite N. We give an analytical expression for the number of retrieval errors and show that, by increasing the number of stored patterns over a certain threshold, the errors start to decrease and reach values below unit for P ≫ N. We demonstrate that the strongest trade-off between efficiency and effectiveness relies on the number of patterns (P) that are stored in the network by appropriately fixing the connection weights. When P≫N and the diagonal elements of the adjacency matrix are not forced to be zero, the optimal storage capacity is obtained with a number of stored memories much larger than previously reported. This theory paves the way to the design of RNN with high storage capacity and able to retrieve the desired pattern without distortions. PMID:28119595

  8. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush

    2002-10-26

    This is the eighth Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. The final biomass co-firing test burn was conducted during this quarter. In this test (Test 14), up to 20% by weight dry switchgrass was comilled with Jim Walters No.7 mine coal and injected through the single-register burner. Jim Walters No.7 coal is a low-volatility, low-sulfur ({approx}0.7% S) Eastern bituminous coal. The results of this test are presented in this quarterly report. Progress has continued to be made in implementing a modeling approach to combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO{sub x} emissions and unburned carbon levels in the furnace exhaust. The REI Configurable Fireside Simulator (CFS) is now in regular use. Presently, the CFS is being used to generate CFD calculations for completed tests with Powder River Basin coal and low-volatility (Jim Walters No.7 Mine) coal. Niksa Energy Associates will use the results of these CFD simulations to complete their validation of the NOx/LOI predictive model. Work has started on the project final report.

  9. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush

    2001-07-17

    This is the third Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. Three additional biomass co-firing test burns have been conducted. In the first test (Test 3), up to 20% by weight dry hardwood sawdust and dry switchgrass was injected through the center of the burner. In the second test (Test 4), 100% Pratt seam coal was burned in a repeat of the initial test condition of Test 1, to reconcile irregularities in the data from the first test. In the third test (Test 5), up to 20% by weight dry hardwood sawdust and dry switchgrass was injected through an external pipe directed toward the exit of the burner. Progress has continued in developing a modeling approach to synthesize the reaction time and temperature distributions that will be produced by computational fluid dynamic models of the pilot-scale combustion furnace and the char burnout and chemical reaction kinetics that will predict NOx emissions and unburned carbon levels in the furnace exhaust. Additional results of CFD modeling efforts have been received and Preparations are under way for continued pilot-scale combustion experiments. Finally, a presentation was made at a Biomass Cofiring Project Review Meeting held at the NETL in Pittsburgh, PA on June 20-21.

  10. System level permeability modeling of porous hydrogen storage materials.

    Energy Technology Data Exchange (ETDEWEB)

    Kanouff, Michael P.; Dedrick, Daniel E.; Voskuilen, Tyler (Purdue University, West Lafayette, IN)

    2010-01-01

    A permeability model for hydrogen transport in a porous material is successfully applied to both laboratory-scale and vehicle-scale sodium alanate hydrogen storage systems. The use of a Knudsen number dependent relationship for permeability of the material in conjunction with a constant area fraction channeling model is shown to accurately predict hydrogen flow through the reactors. Generally applicable model parameters were obtained by numerically fitting experimental measurements from reactors of different sizes and aspect ratios. The degree of channeling was experimentally determined from the measurements and found to be 2.08% of total cross-sectional area. Use of this constant area channeling model and the Knudsen dependent Young & Todd permeability model allows for accurate prediction of the hydrogen uptake performance of full-scale sodium alanate and similar metal hydride systems.

  11. Deployment models for commercialized carbon capture and storage.

    Science.gov (United States)

    Esposito, Richard A; Monroe, Larry S; Friedman, Julio S

    2011-01-01

    Even before technology matures and the regulatory framework for carbon capture and storage (CCS) has been developed, electrical utilities will need to consider the logistics of how widespread commercial-scale operations will be deployed. The framework of CCS will require utilities to adopt business models that ensure both safe and affordable CCS operations while maintaining reliable power generation. Physical models include an infrastructure with centralized CO(2) pipelines that focus geologic sequestration in pooled regional storage sites or supply CO(2) for beneficial use in enhanced oil recovery (EOR) and a dispersed plant model with sequestration operations which take place in close proximity to CO(2) capture. Several prototypical business models, including hybrids of these two poles, will be in play including a self-build option, a joint venture, and a pay at the gate model. In the self-build model operations are vertically integrated and utility owned and operated by an internal staff of engineers and geologists. A joint venture model stresses a partnership between the host site utility/owner's engineer and external operators and consultants. The pay to take model is turn-key external contracting to a third party owner/operator with cash positive fees paid out for sequestration and cash positive income for CO(2)-EOR. The selection of a business model for CCS will be based in part on the desire of utilities to be vertically integrated, source-sink economics, and demand for CO(2)-EOR. Another element in this decision will be how engaged a utility decides to be and the experience the utility has had with precommercial R&D activities. Through R&D, utilities would likely have already addressed or at least been exposed to the many technical, regulatory, and risk management issues related to successful CCS. This paper provides the framework for identifying the different physical and related prototypical business models that may play a role for electric utilities in

  12. A modelling exercise to examine variations of NOx concentrations on adjacent footpaths in a street canyon: The importance of accounting for wind conditions and fleet composition.

    Science.gov (United States)

    Gallagher, J

    2016-04-15

    Personal measurement studies and modelling investigations are used to examine pollutant exposure for pedestrians in the urban environment: each presenting various strengths and weaknesses in relation to labour and equipment costs, a sufficient sampling period and the accuracy of results. This modelling exercise considers the potential benefits of modelling results over personal measurement studies and aims to demonstrate how variations in fleet composition affects exposure results (presented as mean concentrations along the centre of both footpaths) in different traffic scenarios. A model of Pearse Street in Dublin, Ireland was developed by combining a computational fluid dynamic (CFD) model and a semi-empirical equation to simulate pollutant dispersion in the street. Using local NOx concentrations, traffic and meteorological data from a two-week period in 2011, the model were validated and a good fit was presented. To explore the long-term variations in personal exposure due to variations in fleet composition, synthesised traffic data was used to compare short-term personal exposure data (over a two-week period) with the results for an extended one-year period. Personal exposure during the two-week period underestimated the one-year results by between 8% and 65% on adjacent footpaths. The findings demonstrate the potential for relative differences in pedestrian exposure to exist between the north and south footpaths due to changing wind conditions in both peak and off-peak traffic scenarios. This modelling approach may help overcome potential under- or over-estimations of concentrations in personal measurement studies on the footpaths. Further research aims to measure pollutant concentrations on adjacent footpaths in different traffic and wind conditions and to develop a simpler modelling system to identify pollutant hotspots on our city footpaths so that urban planners can implement improvement strategies to improve urban air quality.

  13. Development of climate data storage and processing model

    Science.gov (United States)

    Okladnikov, I. G.; Gordov, E. P.; Titov, A. G.

    2016-11-01

    We present a storage and processing model for climate datasets elaborated in the framework of a virtual research environment (VRE) for climate and environmental monitoring and analysis of the impact of climate change on the socio-economic processes on local and regional scales. The model is based on a «shared nothings» distributed computing architecture and assumes using a computing network where each computing node is independent and selfsufficient. Each node holds a dedicated software for the processing and visualization of geospatial data providing programming interfaces to communicate with the other nodes. The nodes are interconnected by a local network or the Internet and exchange data and control instructions via SSH connections and web services. Geospatial data is represented by collections of netCDF files stored in a hierarchy of directories in the framework of a file system. To speed up data reading and processing, three approaches are proposed: a precalculation of intermediate products, a distribution of data across multiple storage systems (with or without redundancy), and caching and reuse of the previously obtained products. For a fast search and retrieval of the required data, according to the data storage and processing model, a metadata database is developed. It contains descriptions of the space-time features of the datasets available for processing, their locations, as well as descriptions and run options of the software components for data analysis and visualization. The model and the metadata database together will provide a reliable technological basis for development of a high- performance virtual research environment for climatic and environmental monitoring.

  14. HIERARCHICAL METHODOLOGY FOR MODELING HYDROGEN STORAGE SYSTEMS PART II: DETAILED MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, B; Donald L. Anton, D

    2008-12-22

    There is significant interest in hydrogen storage systems that employ a media which either adsorbs, absorbs or reacts with hydrogen in a nearly reversible manner. In any media based storage system the rate of hydrogen uptake and the system capacity is governed by a number of complex, coupled physical processes. To design and evaluate such storage systems, a comprehensive methodology was developed, consisting of a hierarchical sequence of models that range from scoping calculations to numerical models that couple reaction kinetics with heat and mass transfer for both the hydrogen charging and discharging phases. The scoping models were presented in Part I [1] of this two part series of papers. This paper describes a detailed numerical model that integrates the phenomena occurring when hydrogen is charged and discharged. A specific application of the methodology is made to a system using NaAlH{sub 4} as the storage media.

  15. Evaluation of NOx emission inventories in California using multi-satellite data sets, in-situ airborne measurements, and regional model simulations during the CalNex 2010 field campaign

    Science.gov (United States)

    Kim, S.; Ahmadov, R.; Angevine, W. M.; Boersma, F. F.; Brioude, J.; Browne, E. C.; Bucsela, E. J.; Burrows, J. P.; Celarier, E. A.; Cohen, R. C.; Frost, G. J.; Krotkov, N. A.; Lamsal, L.; Lee, S.; Martin, R. V.; McKeen, S. A.; Pollack, I. B.; Richter, A.; Russell, A. R.; Ryerson, T. B.; Trainer, M.; Valin, L. C.

    2011-12-01

    Satellite NO2 column measurements indicate large NOx emissions from urban and agricultural sources in California. In this presentation, we highlight the NOx sources identified in California using the satellite measurements. Comparison of regional model-simulated NO2 columns with satellite retrievals has proven useful in evaluating emission inventories for various sectors. We compare the NO2 columns from the WRF-Chem model with the multi-satellite data sets from different instruments and retrieval groups for a variety of California sources. Use of multiple satellite data sets help to define the uncertainties in the satellite retrievals. In addition, the CalNex 2010 intensive field campaign provides a unique opportunity to independently assess California's emission inventories. The in-situ airborne observations from CalNex 2010 and fine-resolution model simulations are used to estimate the accuracy of the satellite NO2 column retrievals.

  16. Determination of the NOx loading of an automotive lean NOx trap by directly monitoring the electrical properties of the catalyst material itself.

    Science.gov (United States)

    Fremerey, Peter; Reiss, Sebastian; Geupel, Andrea; Fischerauer, Gerhard; Moos, Ralf

    2011-01-01

    Recently, it has been shown that the degree of loading of several types of automotive exhaust aftertreatment devices can be directly monitored in situ and in a contactless way by a microwave-based method. The goal of this study was to clarify whether this method can also be applied to NOx storage and reduction catalysts (lean NOx traps) in order to obtain further knowledge about the reactions occurring in the catalyst and to compare the results with those obtained by wirebound NOx loading sensors. It is shown that both methods are able to detect the different catalyst loading states. However, the sensitivity of the microwave-based method turned out to be small compared to that previously observed for other exhaust aftertreatment devices. This may limit the practical applicability of the microwave-based NOx loading detection in lean NOx traps.

  17. Determination of the NOx Loading of an Automotive Lean NOx Trap by Directly Monitoring the Electrical Properties of the Catalyst Material Itself

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2011-08-01

    Full Text Available Recently, it has been shown that the degree of loading of several types of automotive exhaust aftertreatment devices can be directly monitored in situ and in a contactless way by a microwave-based method. The goal of this study was to clarify whether this method can also be applied to NOx storage and reduction catalysts (lean NOx traps in order to obtain further knowledge about the reactions occurring in the catalyst and to compare the results with those obtained by wirebound NOx loading sensors. It is shown that both methods are able to detect the different catalyst loading states. However, the sensitivity of the microwave-based method turned out to be small compared to that previously observed for other exhaust aftertreatment devices. This may limit the practical applicability of the microwave-based NOx loading detection in lean NOx traps.

  18. Optimization of Experimental Model Parameter Identification for Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Rosario Morello

    2013-09-01

    Full Text Available The smart grid approach is envisioned to take advantage of all available modern technologies in transforming the current power system to provide benefits to all stakeholders in the fields of efficient energy utilisation and of wide integration of renewable sources. Energy storage systems could help to solve some issues that stem from renewable energy usage in terms of stabilizing the intermittent energy production, power quality and power peak mitigation. With the integration of energy storage systems into the smart grids, their accurate modeling becomes a necessity, in order to gain robust real-time control on the network, in terms of stability and energy supply forecasting. In this framework, this paper proposes a procedure to identify the values of the battery model parameters in order to best fit experimental data and integrate it, along with models of energy sources and electrical loads, in a complete framework which represents a real time smart grid management system. The proposed method is based on a hybrid optimisation technique, which makes combined use of a stochastic and a deterministic algorithm, with low computational burden and can therefore be repeated over time in order to account for parameter variations due to the battery’s age and usage.

  19. AMMONIA-FREE NOx CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2006-06-01

    This report describes a novel NOx control system that has the potential to drastically reduce cost, and enhance performance, operation and safety of power plant NOx control. The new system optimizes the burner and the furnace to achieve very low NOx levels and to provide an adequate amount of CO, and uses the CO for reducing NO both in-furnace and over a downstream AFSCR (ammonia-free selective catalytic reduction) reactor. The AF-SCR combines the advantages of the highly successful SCR technology for power plants and the TWC (three-way catalytic converter) widely used on automobiles. Like the SCR, it works in oxidizing environment of combustion flue gas and uses only base metal catalysts. Like the TWC, the AF-SCR removes NO and excess CO simultaneously without using any external reagent, such as ammonia. This new process has been studied in a development program jointed funded by the US Department of Energy and Foster Wheeler. The report outlines the experimental catalyst work performed on a bench-scale reactor, including test procedure, operating conditions, and results of various catalyst formulations. Several candidate catalysts, prepared with readily available transition metal oxides and common substrate materials, have shown over 80-90% removal for both NO and CO in oxidizing gas mixtures and at elevated temperatures. A detailed combustion study of a 400 MWe coal-fired boiler, applying computational fluid dynamics techniques to model boiler and burner design, has been carried out to investigate ways to optimize the combustion process for the lowest NOx formation and optimum CO/NO ratios. Results of this boiler and burner optimization work are reported. The paper further discusses catalyst scale-up considerations and the conceptual design of a 400 MWe size AF-SCR reactor, as well as economics analysis indicating large cost savings of the ammonia-free NOx control process over the current SCR technology.

  20. NOX4 is an early initiator of neuropathic pain.

    Science.gov (United States)

    Geis, Christian; Geuss, Eva; Sommer, Claudia; Schmidt, Harald H H W; Kleinschnitz, Christoph

    2017-02-01

    Treatment of neuropathic pain remains challenging as the etiology is heterogeneous and pathomechanisms are incompletely understood. One possible mechanism is oxidative stress due to unphysiological reactive oxygen species (ROS) formation. The only know dedicated enzymatic source of ROS are NADPH oxidases of which the type 4 isoform (NOX4) has been suggested to be involved in the subacute and chronic phase of neuropathic pain. Here, we aim to translate this finding into a treatment strategy by examining the efficacy of the NOX1/4-specific inhibitor GKT136901 using the chronic constriction injury (CCI) mouse model of neuropathic pain. Unexpectedly, post-nerve lesion treatment using GKT136901 was ineffective to reduce pain-related behavior after CCI. We therefore re-investigated the role of NOX4 using an independent KO mouse model. Early after CCI we found an increase in pro-inflammatory cytokines, ROS formation and the oxidative stress marker nitrotyrosine in the lesioned nerve together with an upregulated Nox4 gene expression. In NOX4 KO mice, mechanical allodynia was markedly reduced from day 4 after nerve injury as were all ROS related and acute biomarkers. In addition, we observed a reduction in the CCI-induced upregulation of pro-inflammatory cytokines in the sciatic nerve and dorsal root ganglia along with NOX4-deficiency. Thus, we conclude that NOX4 is involved in the development of neuropathic pain states by producing oxidative stress and subsequent cytokine dysregulation at the lesion site. This appears at very early stages immediately after nerve injury explaining ineffectiveness of post-acute pharmacological NOX inhibition. We suggest that future target validation of NOX4 should now focus on defining the possible therapeutic window in human neuropathic pain. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Measurement and model comparison of methacrolein and methyl vinyl ketone concentrations from the OH-initiated oxidation of isoprene under NOx free conditions

    Science.gov (United States)

    Navarro, M. A.; Dusanter, S.; Stevens, P. S.; Hites, R. A.

    2009-12-01

    Isoprene, the dominant natural hydrocarbon emitted into the atmosphere by deciduous trees, contributes significantly to the production of tropospheric ozone, organic nitrates, and secondary VOCs due to its high reactivity with hydroxyl radicals (OH). As a result, the chemical mechanism for the oxidation of isoprene is a subject of considerable interest in atmospheric chemistry. Recent measurements of OH and HO2 radical concentrations in forest environments do not agree with modeled concentrations, bringing into question our understanding of the atmospheric chemistry of isoprene and other reactive biogenic emissions. In this study, a small UV-irradiated reaction chamber was coupled to an on-line mass spectrometer to investigate the formation of isoprene oxidation products under NOx free conditions using UV-photolysis of hydrogen peroxide (H2O2) as the OH source. Time-resolved concentration profiles were measured for the two main products of isoprene oxidation: methacrolein (MAC) and methyl vinyl ketone (MVK). These experimental concentration profiles were compared to the values predicted by both the explicit Master Chemical Mechanism (MCM) and the condensed Regional Atmospheric Chemistry Mechanism (RACM). Several changes to the oxidation mechanism were incorporated, including the addition of recently proposed OH recycling reactions, in order to determine their impact on the predicted yields of MAC and MVK.

  2. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Balyk, Olexandr

    2013-01-01

    options: passive heat storage in the building structure via radiator heating, active heat storage in concrete floors via floor heating, and use of thermal storage tanks for space heating and hot water. It is shown that the model is well qualified for analysing possibilities and system benefits...... be taken into account. In this study, we present a model that facilitates analysing individual heat pumps and complementing heat storages in integration with the energy system, while optimising both investments and operation. The model incorporates thermal building dynamics and covers various heat storage...

  3. Application of a Central Composite Design for the Study of NOx Emission Performance of a Low NOx Burner

    Directory of Open Access Journals (Sweden)

    Marcin Dutka

    2015-04-01

    Full Text Available In this study, the influence of various factors on nitrogen oxides (NOx emissions of a low NOx burner is investigated using a central composite design (CCD approach to an experimental matrix in order to show the applicability of design of experiments methodology to the combustion field. Four factors have been analyzed in terms of their impact on NOx formation: hydrogen fraction in the fuel (0%–15% mass fraction in hydrogen-enriched methane, amount of excess air (5%–30%, burner head position (20–25 mm from the burner throat and secondary fuel fraction provided to the burner (0%–6%. The measurements were performed at a constant thermal load equal to 25 kW (calculated based on lower heating value. Response surface methodology and CCD were used to develop a second-degree polynomial regression model of the burner NOx emissions. The significance of the tested factors over their respective ranges has been evaluated using the analysis of variance and by the consideration of the coefficients of the model equation. Results show that hydrogen addition to methane leads to increased NOx emissions in comparison to emissions from pure methane combustion. Hydrogen content in a fuel is the strongest factor affecting NOx emissions among all the factors tested. Lower NOx formation because of increased excess air was observed when the burner was fuelled by pure methane, but this effect diminished for hydrogen-rich fuel mixtures. NOx emissions were slightly reduced when the burner head was shifted closer to the burner outer tube, whereas a secondary fuel stream provided to the burner was found to have no impact on NOx emissions over the investigated range of factors.

  4. A Comparison of Three Data Models for Text Storage and Retrieval Systems: The Relational Model Revisited

    DEFF Research Database (Denmark)

    Hertzum, Morten

    1994-01-01

    A number of software toolkits exist for the development of text storage and retrieval systems (TSARS). This study compares three data models applicable to such toolkits and discusses the suitability of one of them as the basis of a toolkit unifying all three data models. The three data models are...

  5. Modellization of Metal Hydride Canister for Hydrogen Storage

    Directory of Open Access Journals (Sweden)

    Rocio Maceiras

    2015-06-01

    Full Text Available Hydrogen shows very interesting features for its use on-board applications as fuel cell vehicles. This paper presents the modelling of a tank with a metal hydride alloy for on-board applications, which provides good performance under ambient conditions. The metal hydride contained in the tank is Ti0.98Zr0.02V0.43Fe0.09Cr0.05Mn1.5. A two-dimensional model has been performed for the refuelling process (absorption and the discharge process (desorption. For that, individual models of mass balance, energy balance, reaction kinetics and behaviour of hydrogen gas has been modelled. The model has been developed under Matlab / Simulink© environment. Finally, individual models have been integrated into a global model, and simulated under ambient conditions. With the aim to analyse the temperature influence on the state of charge and filling and emptying time, other simulations were performed at different temperatures. The obtained results allow to conclude that this alloy offers a good behaviour with the discharge process under normal ambient conditions. Keywords: Hydrogen storage; metal hydrides; fuel cell; simulation; board applications

  6. Simultaneous reduction of particulate matter and NO(x) emissions using 4-way catalyzed filtration systems.

    Science.gov (United States)

    Swanson, Jacob J; Watts, Winthrop F; Newman, Robert A; Ziebarth, Robin R; Kittelson, David B

    2013-05-07

    The next generation of diesel emission control devices includes 4-way catalyzed filtration systems (4WCFS) consisting of both NOx and diesel particulate matter (DPM) control. A methodology was developed to simultaneously evaluate the NOx and DPM control performance of miniature 4WCFS made from acicular mullite, an advanced ceramic material (ACM), that were challenged with diesel exhaust. The impact of catalyst loading and substrate porosity on catalytic performance of the NOx trap was evaluated. Simultaneously with NOx measurements, the real-time solid particle filtration performance of catalyst-coated standard and high porosity filters was determined for steady-state and regenerative conditions. The use of high porosity ACM 4-way catalyzed filtration systems reduced NOx by 99% and solid and total particulate matter by 95% when averaged over 10 regeneration cycles. A "regeneration cycle" refers to an oxidizing ("lean") exhaust condition followed by a reducing ("rich") exhaust condition resulting in NOx storage and NOx reduction (i.e., trap "regeneration"), respectively. Standard porosity ACM 4-way catalyzed filtration systems reduced NOx by 60-75% and exhibited 99.9% filtration efficiency. The rich/lean cycling used to regenerate the filter had almost no impact on solid particle filtration efficiency but impacted NOx control. Cycling resulted in the formation of very low concentrations of semivolatile nucleation mode particles for some 4WCFS formulations. Overall, 4WCFS show promise for significantly reducing diesel emissions into the atmosphere in a single control device.

  7. A convolution model of rock bed thermal storage units

    Science.gov (United States)

    Sowell, E. F.; Curry, R. L.

    1980-01-01

    A method is presented whereby a packed-bed thermal storage unit is dynamically modeled for bi-directional flow and arbitrary input flow stream temperature variations. The method is based on the principle of calculating the output temperature as the sum of earlier input temperatures, each multiplied by a predetermined 'response factor', i.e., discrete convolution. A computer implementation of the scheme, in the form of a subroutine for a widely used solar simulation program (TRNSYS) is described and numerical results compared with other models. Also, a method for efficient computation of the required response factors is described; this solution is for a triangular input pulse, previously unreported, although the solution method is also applicable for other input functions. This solution requires a single integration of a known function which is easily carried out numerically to the required precision.

  8. A Dissipative Model for Hydrogen Storage: Existence and Regularity Results

    CERN Document Server

    Chiodaroli, Elisabetta

    2010-01-01

    We prove global existence of a solution to an initial and boundary value problem for a highly nonlinear PDE system. The problem arises from a termomechanical dissipative model describing hydrogen storage by use of metal hydrides. In order to treat the model from an analytical point of view, we formulate it as a phase transition phenomenon thanks to the introduction of a suitable phase variable. Continuum mechanics laws lead to an evolutionary problem involving three state variables: the temperature, the phase parameter and the pressure. The problem thus consists of three coupled partial differential equations combined with initial and boundary conditions. Existence and regularity of the solutions are here investigated by means of a time discretization-a priori estimate-passage to the limit procedure joined with compactness and monotonicity arguments.

  9. OSIRIS observations of a tongue of NOx in the lower stratosphere at the Antarctic vortex edge: comparison with a high-resolution simulation from the Global Environmental Multiscale (GEM) model

    Energy Technology Data Exchange (ETDEWEB)

    Sioris, C.E.; McLinden, C.A.; Rochon, Y.J.; McElroy, C.T. [Environment Canada, Toronto, ON (Canada). Atmospheric Science and Technology Directorate; Chabrillat, S. [Belgian Inst. for Space Aeronomy, Brussels (Belgium); Haley, C.S. [York Univ., Toronto, ON (Canada); Menard, R.; Charron, M. [Environment Canada, Dorval, ON (Canada). Atmospheric Science and Technology Directorate

    2007-11-15

    An optical spectrograph and infrared imager system (OSIRIS) aboard the Odin satellite measures limb-scattered sunlight in the 280 to 810 nm range. This paper addressed the challenge of interpreting nitrogen dioxide (NO{sub 2}) profile observations in the polar lower stratosphere. Interpretations of these profile observations can be facilitated by first converting the measurements to NO{sub x} using a photochemical model in order to compare directly with simulated NO{sub x} from a 3-dimensional chemical transport model such as the Global Environmental Multiscale (GEM) model. In this study, GEM was used to simulate a tongue of NO{sub x} observed by OSIRIS as it circulated inside the Antarctic vortex edge. The objective was to clarify one of several OSIRIS observations of enhanced lower stratospheric NO{sub 2} in the Antarctic in early austral spring. Another objective was to demonstrate the variability in lower stratospheric NO{sub x} at polar latitudes due to dynamical processes. Selected NOx profiles of the Antarctic lower stratosphere inferred from OSIRIS NO{sub 2} observations were presented from the austral spring of 2003. A tongue of NOx at 100 hPa was observed, with a concentration typical of the middle stratosphere. GEM simulations revealed that this small-scale tongue of NOx-rich air descended into the lower stratosphere. The tongue was formed as a result of a Rossby wave breaking, transporting NOx from the pole, where larger concentrations had recently appeared, to the edge of the vortex. A detailed illustration of the 3-dimensional structure of the breaking wave was also presented. 17 refs., 1 tab., 10 figs.

  10. Modelling challenges for battery materials and electrical energy storage

    Science.gov (United States)

    Muller, Richard P.; Schultz, Peter A.

    2013-10-01

    Many vital requirements in world-wide energy production, from the electrification of transportation to better utilization of renewable energy production, depend on developing economical, reliable batteries with improved performance characteristics. Batteries reduce the need for gasoline and liquid hydrocarbons in an electrified transportation fleet, but need to be lighter, longer-lived and have higher energy densities, without sacrificing safety. Lighter and higher-capacity batteries make portable electronics more convenient. Less expensive electrical storage accelerates the introduction of renewable energy to electrical grids by buffering intermittent generation from solar or wind. Meeting these needs will probably require dramatic changes in the materials and chemistry used by batteries for electrical energy storage. New simulation capabilities, in both methods and computational resources, promise to fundamentally accelerate and advance the development of improved materials for electric energy storage. To fulfil this promise significant challenges remain, both in accurate simulations at various relevant length scales and in the integration of relevant information across multiple length scales. This focus section of Modelling and Simulation in Materials Science and Engineering surveys the challenges of modelling for energy storage, describes recent successes, identifies remaining challenges, considers various approaches to surmount these challenges and discusses the potential of these methods for future battery development. Zhang et al begin with atoms and electrons, with a review of first-principles studies of the lithiation of silicon electrodes, and then Fan et al examine the development and use of interatomic potentials to the study the mechanical properties of lithiated silicon in larger atomistic simulations. Marrocchelli et al study ionic conduction, an important aspect of lithium-ion battery performance, simulated by molecular dynamics. Emerging high

  11. Bulk energy storage increases United States electricity system emissions.

    Science.gov (United States)

    Hittinger, Eric S; Azevedo, Inês M L

    2015-03-03

    Bulk energy storage is generally considered an important contributor for the transition toward a more flexible and sustainable electricity system. Although economically valuable, storage is not fundamentally a "green" technology, leading to reductions in emissions. We model the economic and emissions effects of bulk energy storage providing an energy arbitrage service. We calculate the profits under two scenarios (perfect and imperfect information about future electricity prices), and estimate the effect of bulk storage on net emissions of CO2, SO2, and NOx for 20 eGRID subregions in the United States. We find that net system CO2 emissions resulting from storage operation are nontrivial when compared to the emissions from electricity generation, ranging from 104 to 407 kg/MWh of delivered energy depending on location, storage operation mode, and assumptions regarding carbon intensity. Net NOx emissions range from -0.16 (i.e., producing net savings) to 0.49 kg/MWh, and are generally small when compared to average generation-related emissions. Net SO2 emissions from storage operation range from -0.01 to 1.7 kg/MWh, depending on location and storage operation mode.

  12. A Fundamental Consideration on NOx Adsorber Technology for DI Diesel Application

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Howard L.; Huang, Shyan C.; Yu, Robert C. (Cummins, Inc.); Wan, C. Z. (Engelhard Corp.); Howden, Ken (U.S. Dept. of Energy)

    2002-10-01

    Diesel engines are far more efficient than gasoline engines of comparable size, and emit less greenhouse gases that have been implicated in global warming. In 2000, the US EPA proposed very stringent emissions standards to be introduced in 2007 along with low sulfur (< 15 ppm) diesel fuel. The California Air Resource Board (CARB) has also established the principle that future diesel fueled vehicles should meet the same low emissions standards as gasoline fueled vehicles and the EPA followed suit with its Tier II emissions regulation. Achieving such low emissions cannot be done through engine development and fuel reformulation alone, and requires application of NOx and particulate matter (PM) aftertreatment control devices. There is a widespread consensus that NOx adsorbers and particulate filter are required in order for diesel engines to meet the 2007 emissions regulations for NOx and PM. In this paper, the key exhaust characteristics from an advanced diesel engine are reviewed. Development of the NOx adsorber technology is discussed. Spectroscopic techniques are applied to understand the underlying chemical reactions over the catalyst surface during NOx trapping and regeneration periods. In-situ surface probes are useful in providing not only thermodynamic and kinetics information required for model development but also a fundamental understanding of storage capacity and degradation mechanisms. The distribution of various nitration/sulfation species is related to surface basicity. Surface displacement reactions of carbonates also play roles in affecting the trapping capability of NOx adsorbers. When ultralow-S fuel is used as a reductant during the regeneration, sulfur induced performance degradation is still observed in an aged catalyst. Other possible sources related to catalyst deactivation include incomplete reduction of surface nitration, coke formation derived from incomplete hydrocarbon burning, and lubricant formulations. Sulfur management and the

  13. Characterization of NOx emission in the suburbs of Tokyo based on simultaneous and real-time observations of atmospheric Ox and NOx

    Science.gov (United States)

    Matsumoto, J.

    2013-12-01

    .1 ppbv for Ox and 0.5 ppbv for NOx (60-s integration, S/N = 3). The observation test in the suburbs of Tokyo was conducted in April 2013 at Tokorozawa Campus, Waseda University. During the campaign, 48 cases of ';NOx spikes', for which NOx levels significantly varied in the second time scale due to local NOx emission, were captured. NO2/NOx ratio in the exhaust gas was estimated as the slope of regression line between 1-s series data of Ox and those of NOx observed during each spike. The average of acquired NO2/NOx ratio was 0.10. Thus, as a result of observations of real atmosphere, the present NO2/NOx ratio in the exhaust gases in the suburbs of Tokyo was 0.10 as average, which was mainly due to exhausts of automobiles. However, when the individual cases were considered, NO2/NOx could vary from 0.00 to 0.30. Such a wide range of NO2/NOx ratio may be due to (1) difference of source types (eg. automobiles, power generator) and (2) difference of conditions of sources (eg. engines, filters of exhaust). For example, NO2/NOx ratio for hybrid electric vehicles may be different from those for conventional cars. When diffusion of such new model cars can change NOx emission in near future, the present method of simultaneous and real-time monitoring of Ox and NOx in the atmosphere can be useful and promising for characterization of NOx emission.

  14. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false NOX RACT and NOX conformity exemption... RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of nitrogen (NOX) reasonably available control technology (RACT) and NOX conformity exemption request submitted...

  15. 40 CFR 86.1860-04 - How to comply with the Tier 2 and interim non-Tier 2 fleet average NOX standards.

    Science.gov (United States)

    2010-07-01

    ... NOX standards do not apply to a manufacturer whose U.S. LDV/T and MDPV sales are 100% Tier 2 LDV/Ts... sufficient Tier 2 NOX credits, interim non-Tier 2 LDV/LLDT NOX credits or interim non-Tier 2 HLDT/MDPV NOX...) Their Tier 2 LDV/LLDT and Tier 2 HLDT/MDPV fleet average NOX emissions for each model year through 2008...

  16. Modeling, hybridization, and optimal charging of electrical energy storage systems

    Science.gov (United States)

    Parvini, Yasha

    The rising rate of global energy demand alongside the dwindling fossil fuel resources has motivated research for alternative and sustainable solutions. Within this area of research, electrical energy storage systems are pivotal in applications including electrified vehicles, renewable power generation, and electronic devices. The approach of this dissertation is to elucidate the bottlenecks of integrating supercapacitors and batteries in energy systems and propose solutions by the means of modeling, control, and experimental techniques. In the first step, the supercapacitor cell is modeled in order to gain fundamental understanding of its electrical and thermal dynamics. The dependence of electrical parameters on state of charge (SOC), current direction and magnitude (20-200 A), and temperatures ranging from -40°C to 60°C was embedded in this computationally efficient model. The coupled electro-thermal model was parameterized using specifically designed temporal experiments and then validated by the application of real world duty cycles. Driving range is one of the major challenges of electric vehicles compared to combustion vehicles. In order to shed light on the benefits of hybridizing a lead-acid driven electric vehicle via supercapacitors, a model was parameterized for the lead-acid battery and combined with the model already developed for the supercapacitor, to build the hybrid battery-supercapacitor model. A hardware in the loop (HIL) setup consisting of a custom built DC/DC converter, micro-controller (muC) to implement the power management strategy, 12V lead-acid battery, and a 16.2V supercapacitor module was built to perform the validation experiments. Charging electrical energy storage systems in an efficient and quick manner, motivated to solve an optimal control problem with the objective of maximizing the charging efficiency for supercapacitors, lead-acid, and lithium ion batteries. Pontryagins minimum principle was used to solve the problems

  17. Use of Combined Observational- and Model-Derived Photochemical Indicators to Assess the O3-NOx-VOC System Sensitivity in Urban Areas

    Directory of Open Access Journals (Sweden)

    Edson R. Carrillo-Torres

    2017-01-01

    Full Text Available Tropospheric levels of O3 have historically exceeded the official annual Mexican standards within the Monterrey Metropolitan Area (MMA in NE Mexico. High-frequency and high-precision measurements of tropospheric O3, NOy, NO2, NO, CO, SO2, PM10 and PM2.5 were made at the Obispado monitoring site near the downtown MMA from September 2012 to August 2013. The seasonal cycles of O3 and NOy are driven by changes in meteorology and to a lesser extent by variations in primary emissions. The NOy levels were positively correlated with O3 precursors and inversely correlated with O3 and wind speed. Recorded data were used to assess the O3-Volatile Organic Compounds (VOC-NOx system’s sensitivity through an observational-based approach. The photochemical indicator O3/NOy was derived from measured data during the enhanced O3 production period (12:00–18:00 Central Daylight Time (CDT, GMT-0500. The O3/NOy ratios calculated for this time period showed that the O3 production within the MMA is VOC sensitive. A box model simulation of production rates of HNO3 (PHNO3 and total peroxides (Pperox carried out for O3 episodes in fall and spring confirmed the VOC sensitivity within the MMA environment. No significant differences were observed in O3/NOy from weekdays to weekends or for PHNO3/Pperox ratios, confirming the limiting role of VOCs in O3 production within the MMA. The ratified photochemical regime observed may allow the environmental authorities to revise and verify the current policies for air quality control within the MMA.

  18. Model analysis of the effects of atmospheric drivers on storage water use in Scots pine

    Directory of Open Access Journals (Sweden)

    H. Verbeeck

    2007-08-01

    Full Text Available Storage water use is an indirect consequence of the interplay between different meteorological drivers through their effect on water flow and water potential in trees. We studied these microclimatic drivers of storage water use in Scots pine (Pinus sylvestris L. growing in a temperate climate. The storage water use was modeled using the ANAFORE model, integrating a dynamic water flow and – storage model with a process-based transpiration model. The model was calibrated and validated with sap flow measurements for the growing season of 2000 (26 May–18 October.

    Because there was no severe soil drought during the study period, we were able to study atmospheric effects. Incoming radiation and vapour pressure deficit (VPD were the main atmospheric drivers of storage water use. The general trends of sap flow and storage water use are similar, and follow more or less the pattern of incoming radiation. Nevertheless, considerable differences in the day-to-day pattern of sap flow and storage water use were observed. VPD was determined to be one of the main drivers of these differences. During dry atmospheric conditions (high VPD storage water use was reduced. This reduction was higher than the reduction in measured sap flow. Our results suggest that the trees did not rely more on storage water during periods of atmospheric drought, without severe soil drought. The daily minimum tree water content was lower in periods of high VPD, but the reserves were not completely depleted after the first day of high VPD, due to refilling during the night.

    Nevertheless, the tree water content deficit was a third important factor influencing storage water use. When storage compartments were depleted beyond a threshold, storage water use was limited due to the low water potential in the storage compartments. The maximum relative contribution of storage water to daily transpiration was also constrained by an increasing tree water content

  19. ADVANCED BIOMASS REBURNING FOR HIGH EFFICIENCY NOx CONTROL AND BIOMASS REBURNING - MODELING/ENGINEERING STUDIES JOINT FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Vladimir M. Zamansky; Mark S. Sheldon; Vitali V. Lissianski; Peter M. Maly; David K. Moyeda; Antonio Marquez; W. Randall Seeker

    2000-10-01

    This report presents results of studies under a Phase II SBIR program funded by the U. S. Department of Agriculture, and a closely coordinated project sponsored by the DOE National Energy Technology Laboratory (NETL, formerly FETC). The overall Phase II objective of the SBIR project is to experimentally optimize the biomass reburning technologies and conduct engineering design studies needed for process demonstration at full scale. The DOE project addresses supporting issues for the process design including modeling activities, economic studies of biomass handling, and experimental evaluation of slagging and fouling. The performance of biomass has been examined in a 300 kW (1 x 10{sup 6} Btu/hr) Boiler Simulator Facility under different experimental conditions. Fuels under investigation include furniture waste, willow wood and walnut shells. Tests showed that furniture pellets and walnut shells provided similar NO{sub x} control as that of natural gas in basic reburning at low heat inputs. Maximum NO{sub x} reduction achieved with walnut shell and furniture pellets was 65% and 58% respectively. Willow wood provided a maximum NO{sub x} reduction of 50% and was no better than natural gas at any condition tested. The efficiency of biomass increases when N-agent is injected into reburning and/or burnout zones, or along with OFA (Advanced Reburning). Co-injection of Na{sub 2}CO{sub 3} with N-agent further increases efficiency of NO{sub x} reduction. Maximum NO{sub x} reduction achieved with furniture pellets and willow wood in Advanced Reburning was 83% and 78% respectively. All combustion experiments of the Phase II project have been completed. All objectives of the experimental tasks were successfully met. The kinetic model of biomass reburning has been developed. Model agrees with experimental data for a wide range of initial conditions and thus correctly represents main features of the reburning process. Modeling suggests that the most important factors that provide

  20. Source apportionment and health effect of NOx over the Pearl River Delta region in southern China.

    Science.gov (United States)

    Lu, Xingcheng; Yao, Teng; Li, Ying; Fung, Jimmy C H; Lau, Alexis K H

    2016-05-01

    As one of the most notorious atmospheric pollutants, NOx not only promotes the formation of ozone but also has adverse health effects on humans. It is therefore of great importance to study the sources of NOx and its effects on human health. The Comprehensive Air Quality Model (CAMx) modeling system and ozone source apportionment technology (OSAT) were used to study the contribution of NOx from different emission sources over southern China. The results indicate that heavy duty diesel vehicles (HDDVs) and industrial point sources are the two major local NOx sources, accounting for 30.8% and 18.5% of local NOx sources, respectively. In Hong Kong, marine emissions contributed around 43.4% of local NOx in 2011. Regional transport is another important source of this pollutant, especially in February and November, and it can contribute over 30% of ambient NOx on average. Power plant point emission is an significant regional source in Zhuhai, Zhongshan and Foshan. The total emission sources are estimated to cause 2119 (0-4405) respiratory deaths and 991 (0-2281) lung cancer deaths due to long-term exposure to NOx in the Pearl River Delta region. Our results suggest that local governments should combine their efforts and vigorously promote further reduction of NOx emissions, especially for those sources that make a substantial contribution to NOx emissions and affect human health: HDDV, LDGV, industrial point sources and marine sources.

  1. Simulation and Modelling of MOFs for Hydrogen Storage

    OpenAIRE

    Başdoğan, Yasemin; Keskin Avcı, Seda

    2015-01-01

    Metal organic frameworks (MOFs) have received significant attention in recent years both from academia and industry since this new class of nanoporous materials has many potential advantages over traditional nanoporous materials in gas storage and separation applications. Hydrogen storage has been one of the most widely investigated applications of MOFs and recent experimental studies have shown that several MOFs are promising for hydrogen storage at low temperatures and moderate pressures. I...

  2. Simulation and Modelling of MOFs for Hydrogen Storage

    OpenAIRE

    Başdoğan, Yasemin; Keskin Avcı, Seda

    2015-01-01

    Metal organic frameworks (MOFs) have received significant attention in recent years both from academia and industry since this new class of nanoporous materials has many potential advantages over traditional nanoporous materials in gas storage and separation applications. Hydrogen storage has been one of the most widely investigated applications of MOFs and recent experimental studies have shown that several MOFs are promising for hydrogen storage at low temperatures and moderate pressures. I...

  3. Aquifer Storage and Recovery : Physical and Geochemical Modelling (SWIFTPHREEQC)of British Aquifers for Aquifer Storage and Recovery Purposes. Part 1, physical modelling and geochemical model calibration

    OpenAIRE

    2000-01-01

    This report describes the progress that has been made in developing models simulating both the physical and geochemical aspects of Aquifer Storage Recovery (ASR) schemes. This work is part of a 30 month project, entitled ASR-UK, which started in April 1999. The report describes progress to the end of 1999. SWIFT is a fully transient 3-Dimensional model that simulates flow and transport of fluids. It is ideally suited to modelling ASR and has been used to simulate the response o...

  4. Modeling and Operational Testing of an Isolated Variable Speed PMSG Wind Turbine with Battery Energy Storage

    OpenAIRE

    BAROTE, L.; MARINESCU, C.

    2012-01-01

    This paper presents the modeling and operational testing of an isolated permanent magnet synchronous generator (PMSG), driven by a small wind turbine with a battery energy storage system during wind speed and load variations. The whole system is initially modeled, including the PMSG, the boost converter and the storage system. The required power for the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropri...

  5. Storage to energy: Modeling the carbon emission of storage task offloading between data centers

    NARCIS (Netherlands)

    Taal, A.; Drupsteen, D.; Makkes, M.X.; Grosso, P.

    2014-01-01

    Storing data in the cloud is becoming a common trend, for both end-customers and data center operators. We propose a method for deciding where to host data storage tasks under the constraint of minimal greenhouse gas emission. The decision on whether to store data locally or store it remotely at a c

  6. Storage to energy: Modeling the carbon emission of storage task offloading between data centers

    NARCIS (Netherlands)

    Taal, A.; Drupsteen, D.; Makkes, M.X.; Grosso, P.

    2014-01-01

    Storing data in the cloud is becoming a common trend, for both end-customers and data center operators. We propose a method for deciding where to host data storage tasks under the constraint of minimal greenhouse gas emission. The decision on whether to store data locally or store it remotely at a

  7. New Concept for Museum Storage Buildings – Evaluation of Building Performance Model for Simulation of Storage

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Knudsen, Lise Ræder; Kollias, Christos Georgios

    2016-01-01

    is close to be CO2 neutral. The analysis shows very good agreement between simulations and measurements, meaning that the proposed methods can be used for designing museum storage buildings. The analysis also shows, that the weather conditions of previous years, affect the indoor environment...

  8. Numerical Modeling of a Shallow Borehole Thermal Energy Storage System

    Science.gov (United States)

    Catolico, N.; Ge, S.; Lu, N.; McCartney, J. S.

    2014-12-01

    Borehole thermal energy storage (BTES) combined with solar thermal energy harvesting is an economic technological system to garner and store energy as well as an environmentally-sustainable alternative for the heating of buildings. The first community-scale BTES system in North America was installed in 2007 in the Drake Landing Solar Community (DLSC), about 35 miles south of Calgary, Canada. The BTES system involves direct circulation of water heated from solar thermal panels in the summer into a storage tank, after which it is circulate within an array of 144 closed-loop geothermal heat exchangers having a depth of 35 m and a spacing of 2.5 m. In the winter the circulation direction is reversed to supply heat to houses. Data collection over a six year period indicates that this system can supply more than 90% of the winter heating energy needs for 52 houses in the community. One major challenge facing the BTES system technology is the relatively low annual efficiency, i.e., the ratio of energy input and output is in the range of 15% to 40% for the system in Drake Landing. To better understand the working principles of BTES and to improve BTES performance for future applications at larger scales, a three-dimensional transient coupled fluid and heat transfer model is established using TOUGH2. The time-dependent injection temperatures and circulation rate measured over the six years of monitoring are used as model input. The simulations are calibrated using soil temperature data measured at different locations over time. The time-dependent temperature distributions within the borehole region agree well with the measured temperatures for soil with an intrinsic permeability of 10e-19 m2, an apparent thermal conductivity of 2.03 W/m°C, and a volumetric heat capacity of 2.31 MJ/m-3°C. The calibrated model serves as the basis for a sensitivity analysis of soil and operational parameters on BTES system efficiency preformed with TOUGH2. Preliminary results suggest 1) BTES

  9. OZONE PRODUCTION EFFICIENCY AND NOX DEPLETION IN AN URBAN PLUME: INTERPRETATION OF FIELD OBSERVATIONS AND IMPLICATIONS FOR EVALUATING O3-NOX-VOC SENSITIVITY

    Science.gov (United States)

    Ozone production efficiency (OPE) can be defined as the number of ozone (O3) molecules photochemically produced by a molecule of NOx (NO + NO2) before it is lost from the NOx - O3 cycle. Here, we consider observational and modeling techniques to evaluate various operational defi...

  10. Sustained Low Temperature NOx Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zha, Yuhui

    2017-04-05

    Increasing regulatory, environmental, and customer pressure in recent years led to substantial improvements in the fuel efficiency of diesel engines, including the remarkable breakthroughs demonstrated through the Super Truck program supported by the U.S. Department of Energy (DOE). On the other hand, these improvements have translated into a reduction of exhaust gas temperatures, thus further complicating the task of controlling NOx emissions, especially in low power duty cycles. The need for improved NOx conversion over these low temperature duty cycles is also observed as requirements tighten with in-use emissions testing. Sustained NOx reduction at low temperatures, especially in the 150-200oC range, shares some similarities with the more commonly discussed cold-start challenge, however poses a number of additional and distinct technical problems. In this project we set a bold target of achieving and maintaining a 90% NOx conversion at the SCR catalyst inlet temperature of 150oC. The project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015. Through this collaboration, we are exploring catalyst formulations and catalyst architectures with enhanced catalytic activity at 150°C; opportunities to approach the desirable ratio of NO and NO2 in the SCR feed gas; options for robust low-temperature reductant delivery; and the requirements for overall system integration. The program is expected to deliver an on-engine demonstration of the technical solution and an assessment of its commercial potential. In the SAE meeting, we will share the initial performance data on engine to

  11. Transport versus energetic particle precipitation: Northern polar stratospheric NOx and ozone in January-March 2012

    Science.gov (United States)

    Päivärinta, S.-M.; Verronen, P. T.; Funke, B.; Gardini, A.; Seppälä, A.; Andersson, M. E.

    2016-05-01

    In early 2012, a strong sudden stratospheric warming (SSW) took place, accompanied by several medium-scale solar proton events (SPEs). Here we use a chemistry transport model (CTM) in order to assess the relative contributions of (1) intensified downward transport of odd nitrogen (NOx) and (2) in situ production of NOx by protons, on stratospheric NOx and ozone during January-March 2012. The CTM is constrained by an upper boundary condition for reactive nitrogen (NOy) species, based on satellite observations from Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat, and includes a new parameterization of the SPE-caused effects on NOy and odd hydrogen (HOx) species. We found that the amount of NOx increases due to both transport and in situ production effects, the intensified descent of NOx dominating the middle and upper stratospheric impact. The model results indicate NOx enhancements of 120-3300% (5-48 ppbv) between 38 and 50 km, caused by the transport of mesosphere/lower thermosphere NOx down to the stratosphere following the SSW. The SPEs increase NOx by up to 820-1200% (14-21 ppbv) at 33 to 50 km. The effect on the stratospheric ozone is larger following the downward transport of NOx than during and after the SPEs. The model predicts ozone losses of up to 17% and 9% at around 40 km due to transport and SPE effects, respectively.

  12. A subsurface runoff parameterization with water storage and recharge based on the Boussinesq-Storage Equation for a Land Surface Model

    Institute of Scientific and Technical Information of China (English)

    TIAN; Xiangjun; XIE; Zhenghui; ZHANG; Shenglei

    2006-01-01

    Subsurface runoff in a land surface model is usually parameterized as a single-valued function of total storage in a basin aquifer reservoir. This kind of parameterization is often single-valued function of storage-discharge under a steady or "quasi-steady" state, which cannot represent the influence of aquifer recharge on subsurface runoff generation. In this paper, a new subsurface runoff parameterization with water storage and recharge based on the Boussinesq-storage equation is developed. This model is validated by a subsurface flow separation algorithm for an example river basin, which shows that the new model can simulate the subsurface flow reasonably.

  13. Climate model biases in seasonally of continental water storage revealed by satellite gravimetry

    Science.gov (United States)

    Swenson, S.C.; Milly, P.C.D.

    2006-01-01

    Satellite gravimetric observations of monthly changes in continental water storage are compared with outputs from five climate models. All models qualitatively reproduce the global pattern of annual storage amplitude, and the seasonal cycle of global average storage is reproduced well, consistent with earlier studies. However, global average agreements mask systematic model biases in low latitudes. Seasonal extrema of low-latitude, hemispheric storage generally occur too early in the models, and model-specific errors in amplitude of the low-latitude annual variations are substantial. These errors are potentially explicable in terms of neglected or suboptimally parameterized water stores in the land models and precipitation biases in the climate models. Copyright 2006 by the American Geophysical Union.

  14. Numerical simulation of NOx formation in a cyclone-opposed coal-fired utility boiler

    Institute of Scientific and Technical Information of China (English)

    LI Fang-qin; REN Jian-xing; WEI Dun-song

    2005-01-01

    In this paper, FLUENT software was used to simulate the burning process in a utility boiler. Chose the kinetics/diffusion-limited as combustion model, two-compet-ingrates as devolatjlization model, RNG k-εmodel as viscous model, and PDF model as combustion turbulent flow model. Numerical calculation of NOx formation in a 330 MW cyclone-opposed coal-fired utility boiler with 32 double air registers was done. The distribution characteristics of temperature, NOx and oxygen concentration in furnace were studied. They were symmetrically distributed in furnace. In the combustion area, temperature and NOx concentration are high, while oxygen concentration is low. Temperature and NOx concentration are declined gradually along with furnace height, while oxygen concentration is raised. The higher the temperature is and the greater the excess air coefficient is, the more NOx formation.

  15. Five-fold way to NOx nirvana

    Energy Technology Data Exchange (ETDEWEB)

    Monro, R.J.; Halloran, J.; Krishnan, R. [RJM Corp., Norwalk, CT (United States)

    2002-03-01

    A layered approach to NOx reduction can achieve up to 90% lower NOx emissions from coal plants, but at much lower cost than the alternatives. The paper explains the main elements of the five layered approach consisting of: burner modifications; overair fire; NOx tempering; selective non-catalytic reduction (SNCR), and amine injection. 1 fig.

  16. A Bilevel Model for Participation of a Storage System in Energy and Reserve Markets

    DEFF Research Database (Denmark)

    Nasrolahpour, Ehsan; Kazempour, Jalal; Zareipour, Hamidreza

    2017-01-01

    We develop a decision-making tool based on a bilevel complementarity model for a merchant price-maker energy storage system to determine the most beneficial trading actions in pool-based markets, including day-ahead (as joint energy and reserve markets) and balancing settlements. The uncertainty...... of net load deviation in real-time is incorporated into the model using a set of scenarios generated from the available forecast in the day-ahead. The objective of this energy storage system is to maximize its expected profit. The day-ahead products of energy storage system include energy as well...... as reserve commitment (as one of the ancillary services), whereas its balancing product is the energy deployed from the committed reserve. The proposed model captures the interactions of different markets and their impacts on the functioning of the storage system. It also provides an insight for storage...

  17. Modelling and monitoring of Aquifer Thermal Energy Storage : impacts of soil heterogeneity, thermal interference and bioremediation

    NARCIS (Netherlands)

    Sommer, W.T.

    2015-01-01

    Modelling and monitoring of Aquifer Thermal Energy Storage Impacts of heterogeneity, thermal interference and bioremediation Wijbrand Sommer
    PhD thesis, Wageningen University, Wageningen, NL (2015)
    ISBN 978-94-6257-294-2 Abstract Aquifer thermal energy storage (ATES) is

  18. Analytical solutions for spin response functions in model storage rings with Siberian Snakes

    Energy Technology Data Exchange (ETDEWEB)

    Mane, S.R. [Convergent Computing Inc., P.O. Box 561, Shoreham, NY 11786 (United States)], E-mail: srmane@optonline.net

    2009-03-01

    I present analytical solutions for the spin response functions for radial field rf dipole spin flippers in models of storage rings with one Siberian Snake or two diametrically opposed orthogonal Siberian Snakes. The solutions can serve as benchmarks tests for computer programs. The spin response functions can be used to calculate the resonance strengths for radial field rf dipole spin flippers in storage rings.

  19. Modelling and monitoring of Aquifer Thermal Energy Storage : impacts of soil heterogeneity, thermal interference and bioremediation

    NARCIS (Netherlands)

    Sommer, W.T.

    2015-01-01

    Modelling and monitoring of Aquifer Thermal Energy Storage Impacts of heterogeneity, thermal interference and bioremediation Wijbrand Sommer
    PhD thesis, Wageningen University, Wageningen, NL (2015)
    ISBN 978-94-6257-294-2 Abstract Aquifer thermal energy storage (ATES) is

  20. State Estimation in the Automotive SCR DeNOx Process

    DEFF Research Database (Denmark)

    Zhou, Guofeng; Jørgensen, John Bagterp; Duwig, Christophe;

    2012-01-01

    Selective catalytic reduction (SCR) of nitrogen oxides (NOx) is a widely applied diesel engine exhaust gas after-treatment technology. For effective NOx removal in a transient operating automotive application, controlled dosing of urea can be used to meet the increasingly restrictive legislations...... on exhaust gas emissions. For advanced control, e.g. Model Predictive Control (MPC), of the SCR process, accurate state estimates are needed. We investigate the performance of the ordinary and the extended Kalman filters based on a simple first principle system model. The performance is tested through...

  1. A software tool to assess uncertainty in transient-storage model parameters using Monte Carlo simulations

    Science.gov (United States)

    Ward, Adam S.; Kelleher, Christa A.; Mason, Seth J. K.; Wagener, Thorsten; McIntyre, Neil; McGlynn, Brian L.; Runkel, Robert L.; Payn, Robert A.

    2017-01-01

    Researchers and practitioners alike often need to understand and characterize how water and solutes move through a stream in terms of the relative importance of in-stream and near-stream storage and transport processes. In-channel and subsurface storage processes are highly variable in space and time and difficult to measure. Storage estimates are commonly obtained using transient-storage models (TSMs) of the experimentally obtained solute-tracer test data. The TSM equations represent key transport and storage processes with a suite of numerical parameters. Parameter values are estimated via inverse modeling, in which parameter values are iteratively changed until model simulations closely match observed solute-tracer data. Several investigators have shown that TSM parameter estimates can be highly uncertain. When this is the case, parameter values cannot be used reliably to interpret stream-reach functioning. However, authors of most TSM studies do not evaluate or report parameter certainty. Here, we present a software tool linked to the One-dimensional Transport with Inflow and Storage (OTIS) model that enables researchers to conduct uncertainty analyses via Monte-Carlo parameter sampling and to visualize uncertainty and sensitivity results. We demonstrate application of our tool to 2 case studies and compare our results to output obtained from more traditional implementation of the OTIS model. We conclude by suggesting best practices for transient-storage modeling and recommend that future applications of TSMs include assessments of parameter certainty to support comparisons and more reliable interpretations of transport processes.

  2. Static and Dynamic Data Models for the Storage Resource Manager v2.2

    CERN Document Server

    Donno, Flavia; CERN. Geneva. IT Department

    2008-01-01

    We present a conceptual model for the Storage Resource Manager, the standard interface adopted for the storage systems of the Worldwide LHC Computing Grid. This model provides a clear and concise definition of the structural and behavioral concepts underlying the interface specification and is meant to support service and application development. Different languages (natural language, UML diagrams, and simple set-theoretic and logical notation) are used to describe different aspects of the model.

  3. Simulation modeling of an automated material storage/retrieval system. [GPSS

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos, J.

    1978-03-01

    A computer simulation model is presented for an automated material storage-and-retrieval system that utilizes bin loading. The model is written in General Purpose Simulation System (GPSS) language, and it functionally simulates incoming job-arrival rates, operator task times, and the travel times of the storage/retrieval vehicle. The model is utilized to evaluate the impact of employing different types of storage policies, the duration of wait times encountered in a priority batch queue, and the expected throughput capacity of the system under either maximum-input or peak-period conditions.

  4. Storage for free: a surprising property of a simple gain-control model of motion aftereffects.

    Science.gov (United States)

    van de Grind, Wim A; van der Smagt, Maarten J; Verstraten, Frans A J

    2004-01-01

    If a motion aftereffect (MAE) for given adaptation conditions has a duration T s, and the eyes are closed after adaptation during a waiting period tw=T s before testing, an unexpected MAE of a 'residual' duration TrT s is experienced. This effect is called 'storage' and it is often quantified by a storage factor sigma=TrT/T, which can reach values up to about 0.7-0.8. The phenomenon and its name have invited explanations in terms of inhibition of recovery during darkness. We present a model based on the opposite idea, that an effective test stimulus quickens recovery relative to darkness or other ineffective test stimuli. The model is worked out in mathematical detail and proves to explain 'storage' data from the literature, on the static MAE (sMAE: an MAE experienced for static test stimuli). We also present results of a psychophysical experiment with moving random pixel arrays, quantifying storage phenomena both for the sMAE and the dynamic MAE (dMAE: an MAE experienced for a random dynamic noise test stimulus). Storage factors for the dMAE are lower than for the sMAE. Our model also gives an excellent description of these new data on storage of the dMAE. The term 'storage' might therefore be a misnomer. If an effective test stimulus influences all direction tuned motion sensors indiscriminately and thus speeds up equalization of gains, one gets the storage phenomenon for free.

  5. Modeling delamination due to thermal stress in optical storage media

    Science.gov (United States)

    Nkansah, M. A.; Evans, K. E.

    1990-04-01

    Finite element analysis is used to calculate the shape of blisters formed in bilayer optical storage media due to the buildup of thermal stresses during laser writing. It is shown that practically usable blisters may be expected to form in a time period of about 15 ns. Such a thermal stress delamination process may also precede melting in conventional pit formation processes.

  6. Lightning NOx Production in CMAQ Part I – Using Hourly NLDN Lightning Strike Data

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  7. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    NARCIS (Netherlands)

    Castellanos, P.; Boersma, K.F.; Werf, van de G.R.

    2014-01-01

    Biomass burning is an important contributor to global total emissions of NOx (NO+NO2). Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome-specific emission factors, defined in units of grams of NO per kilogram of dry matter

  8. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    NARCIS (Netherlands)

    Castellanos, P.; Boersma, K.F.; Werf, van de G.R.

    2014-01-01

    Biomass burning is an important contributor to global total emissions of NOx (NO+NO2). Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome-specific emission factors, defined in units of grams of NO per kilogram of dry matter c

  9. Nature of nitrogen specie in coke and their role in NOx formation during FCC catalyst regeneration.

    NARCIS (Netherlands)

    Babych, Igor V.; Seshan, Kulathuiyer; Lefferts, Leonardus

    2005-01-01

    NOx emission during the regeneration of coked fluid catalytic cracking (FCC) catalysts is an environmental problem. In order to follow the route to NOx formation and try to find ways to suppress it, a coked industrial FCC catalyst has been prepared using model N-containing compounds, e.g., pyridine,

  10. Lightning NOx Production in CMAQ Part I – Using Hourly NLDN Lightning Strike Data

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  11. Variation of radiative forcings and global warming potentials from regional aviation NOx emissions

    Science.gov (United States)

    Skowron, Agnieszka; Lee, David S.; De León, Ruben R.

    2015-03-01

    The response to hemispherical and regional aircraft NOx emissions is explored by using two climate metrics: radiative forcing (RF) and Global Warming Potential (GWP). The global chemistry transport model, MOZART-3 CTM, is applied in this study for a series of incremental aircraft NOx emission integrations to different regions. It was found that the sensitivity of chemical responses per unit emission rate from regional aircraft NOx emissions varies with size of aircraft NOx emission rate and that climate metric values decrease with increasing aircraft NOx emission rates, except for Southeast Asia. Previous work has recognized that aircraft NOx GWPs may vary regionally. However, the way in which these regional GWPs are calculated are critical. Previous studies have added a fixed amount of NOx to different regions. This approach can heavily bias the results of a regional GWP because of the well-established sensitivity of O3 production to background NOx whereby the Ozone Production Efficiency (OPE) is greater at small background NOx. Thus, even a small addition of NOx in a clean-air area can produce a large O3 response. Using this 'fixed addition' method of 0.035 Tg(N) yr-1, results in the greatest effect observed for North Atlantic and Brazil, ∼10.0 mW m-2/Tg(N) yr-1. An alternative 'proportional approach' is also taken that preserves the subtle balance of local NOx-O3-CH4 systems with the existing emission patterns of aircraft and background NOx, whereby a proportional amount of aircraft NOx, 5% (N) yr-1, is added to each region in order to determine the response. This results in the greatest effect observed for North Pacific that with its net NOx RF of 23.7 mW m-2/Tg(N) yr-1 is in contrast with the 'fixed addition' method. For determining regional NOx GWPs, it is argued that the 'proportional' approach gives more representative results. However, a constraint of both approaches is that the regional GWP determined is dependent on the relative global emission pattern

  12. Electrochemical Removal of NOx on Ceria-Based Catalyst-Electrodes

    Directory of Open Access Journals (Sweden)

    Xi Wang

    2017-02-01

    Full Text Available This study reports the electrochemical properties for NOx reduction of a ceria-based mixed ionic electronic conducting porous electrode promoted by Pt nanoparticles, as efficient catalyst for NO oxidation, and BaO, as sorbent to store NOx. This catalytic layer was deposited by screen-printing on a dense membrane of gadolinia-doped ceria, an O2− ionic conductor. The targeted Ba and Pt loadings were 150 and 5 μg/cm2, respectively. The NOx selective electrochemical reduction was performed between 400 °C and 500 °C with and without oxygen in the feed. Variations of the open-circuit voltage with time were found to be a good sensor of the NOx storage process on the ceria-based catalyst-electrode. However, no N2 production was observed in the presence of O2 phase in spite of nitrates formation.

  13. A Smart and Generic Secured Storage Model for Web based Systems

    Directory of Open Access Journals (Sweden)

    P.Iyappan

    2014-09-01

    Full Text Available Nowadays, Recent developments shows that, Cloud computing is a milestone in delivering IT services based on the Internet. Storage as a Service is a type of business model which rents storage space for smaller companies or even for individuals. The vendors are targeting secondary storage by promoting this service which allows a convenient way of managing backups instead of maintaining a large tape library. The key advantage of using Storage service is cost savings of hardware and physical storage spaces. In securing Storage as a Service model, there is a need for a middleware to monitor the data transmission among cloud storage and various clients. The objective of the system aims at developing a smart and integrated dynamic secured storage model which acts as a middleware in supporting all the primary security goals such as confidentiality, data integrity, and accountability. This proposed model will provide secured data dynamics, access controls and auditability. The secured data dynamics is done by Boneh Franklin-Identity Based Cryptography. This model enhances the accounting model in adding indexing policies and provides security in the audit logs through password based cryptography along with AES. This is a generic middleware assisting the basic security features for any cloud environment, so that it can be equipped for any type of system. The main advantage of the proposed system is to reduce the time complexity in encryption and decryption process and also to provide higher degree of security. We also leveraged the implementation of this middleware in a mail server environment with drive option which poses file storage and enables file sharing among the drive users.

  14. Modeling hydrogen storage in boron-substituted graphene decorated with potassium metal atoms

    CSIR Research Space (South Africa)

    Tokarev, A

    2015-03-01

    Full Text Available Boron-substituted graphene decorated with potassium metal atoms was considered as a novel material for hydrogen storage. Density functional theory calculations were used to model key properties of the material, such as geometry, hydrogen packing...

  15. Energy Storage R&D: Thermal Management Studies and Modeling (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, A. A.

    2009-05-01

    Here we summarize NREL's FY09 energy storage R&D studies in the areas of 1. thermal characterization and analysis, 2. cost, life, and performance trade-off studies, and 3. thermal abuse modeling.

  16. Simulation model for wind energy storage systems. Volume I. Technical report. [SIMWEST code

    Energy Technology Data Exchange (ETDEWEB)

    Warren, A.W.; Edsinger, R.W.; Chan, Y.K.

    1977-08-01

    The effort developed a comprehensive computer program for the modeling of wind energy/storage systems utilizing any combination of five types of storage (pumped hydro, battery, thermal, flywheel and pneumatic). An acronym for the program is SIMWEST (Simulation Model for Wind Energy Storage). The level of detail of SIMWEST is consistent with a role of evaluating the economic feasibility as well as the general performance of wind energy systems. The software package consists of two basic programs and a library of system, environmental, and load components. Volume I gives a brief overview of the SIMWEST program and describes the two NASA defined simulation studies.

  17. Dynamic modeling of hybrid energy storage systems coupled to photovoltaic generation in residential applications

    OpenAIRE

    Maclay, JD; J. Brouwer; Samuelsen, GS

    2007-01-01

    A model of a photovoltaic (PV) powered residence in stand-alone configuration was developed and evaluated. The model assesses the sizing, capital costs, control strategies, and efficiencies of reversible fuel cells (RFC), batteries, and ultra-capacitors (UC) both individually, and in combination, as hybrid energy storage devices. The choice of control strategy for a hybrid energy storage system is found to have a significant impact on system efficiency, hydrogen production and component utili...

  18. Influence of fuel quality on vehicular NOx emissions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The quality of gasoline and diesel fuel affects pollutant emissions from vehicles. By applying the COMPLEX model, developed by the MUS EPA and industry to relate fuel composition to vehicle emissions, this paper estimates the influence of improvements in gasoline quality to lower vehicular NOx emissions. A case study is performed for Guangzhou City that has NOr concentrations significantly above the national ambient air quality standards(NAAQS).The paper discusses the potential for reducing NOx in Guangzhou by improving the quality of gasoline.

  19. NOx emission trends in megacities derived from satellite measurements

    Science.gov (United States)

    Konovalov, Igor; Beekmann, Matthias; Richter, Andreas

    2010-05-01

    The effects of air pollutant emissions on both local air quality in megacities and composition of the atmosphere on regional and global scales are currently an important issue of atmospheric researches. In order to properly evaluate these effects, atmospheric models should be provided with accurate information on emissions of major air pollutants. However, such information is frequently very uncertain, as it is documented in literature. The quantification of emissions and related effects is an especially difficult task in the case of developing countries. Recently, it has been demonstrated that satellite measurements of nitrogen dioxide (NO2) can be used as a source of independent information on NOx emissions. In particular, the satellite measurements were used in our earlier studies to improve spatial allocation of NOx emissions, to estimate multi-annual changes of NOx emissions on regional scales and to validate data of traditional emission inventories (see Ref. 1, 2). The goals of the present study are (1) developing an efficient method for estimation of NOx emissions trend in megacity regions by using satellite measurements and an inverse modeling technique and (2) obtaining independent estimates of NOx emission trends in several megacities in Europe and the Middle East in the period from 1996 to 2008. The study is based on the synergetic use of the data for tropospheric NO2 column amounts derived from the long-term GOME and SCIAMACHY measurements and simulations performed by the CHIMERE chemistry transport model. We performed the analysis involving methods of different complexity ranging from estimation of linear trends in the tropospheric NO2 columns retrieved from satellite measurements to evaluation of nonlinear trends in NOx emission estimates obtained with the inverse modeling approach, which, in the given case, involves only very simple and transparent formulations. The most challenging part of the study is the nonlinear trend estimation, which is

  20. Validation of a predictive model for smart control of electrical energy storage

    NARCIS (Netherlands)

    Homan, Bart; Leeuwen, van Richard P.; Smit, Gerard J.M.; Zhu, Lei; Wit, de Jan B.

    2016-01-01

    The purpose of this paper is to investigate the applicability of a relatively simple model which is based on energy conservation for model predictions as part of smart control of thermal and electric storage. The paper reviews commonly used predictive models. Model predictions of charging and discha

  1. Thermal Modeling of NUHOMS HSM-15 and HSM-1 Storage Modules at Calvert Cliffs Nuclear Power Station ISFSI

    Energy Technology Data Exchange (ETDEWEB)

    Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.; Cuta, Judith M.; Collins, Brian A.; Siciliano, Edward R.

    2012-10-01

    As part of the Used Fuel Disposition Campaign of the Department of Energy (DOE), visual inspections and temperature measurements were performed on two storage modules in the Calvert Cliffs Nuclear Power Station’s Independent Spent Fuel Storage Installation (ISFSI). Detailed thermal models models were developed to obtain realistic temperature predictions for actual storage systems, in contrast to conservative and bounding design basis calculations.

  2. Feasibility Study of Energy Storage Systems in Wind/Diesel Applications Using the HOMER Model

    Directory of Open Access Journals (Sweden)

    Andrew Stiel

    2012-10-01

    Full Text Available With an increased focus on solutions to the ensuing “climate crisis”, the need for energy storage systems is becoming increasingly important as a means to increase the penetration of renewable technologies such as wind energy. The Vanadium Redox Battery is one such energy storage system showing considerable potential owing to its flexibility in power output and capacity, high efficiency and long operating life. This study models the use of the Vanadium Redox Battery as an integration technology in realistic large-scale remote wind/diesel power systems using the HOMER Micropower Optimization Model computer program developed by the US National Renewable Energy Laboratory. Results from this modelling demonstrate the significant financial and environmental benefits to be gained in installing energy storage in a wind farm. The storage system considered here was a Vanadium Redox Battery.

  3. NOX2 protects against progressive lung injury and multiple organ dysfunction syndrome.

    Science.gov (United States)

    Whitmore, Laura C; Goss, Kelli L; Newell, Elizabeth A; Hilkin, Brieanna M; Hook, Jessica S; Moreland, Jessica G

    2014-07-01

    Systemic inflammatory response syndrome (SIRS) is a common clinical condition in patients in intensive care units that can lead to complications, including multiple organ dysfunction syndrome (MODS). MODS carries a high mortality rate, and it is unclear why some patients resolve SIRS, whereas others develop MODS. Although oxidant stress has been implicated in the development of MODS, several recent studies have demonstrated a requirement for NADPH oxidase 2 (NOX2)-derived oxidants in limiting inflammation. We recently demonstrated that NOX2 protects against lung injury and mortality in a murine model of SIRS. In the present study, we investigated the role of NOX2-derived oxidants in the progression from SIRS to MODS. Using a murine model of sterile systemic inflammation, we observed significantly greater illness and subacute mortality in gp91(phox-/y) (NOX2-deficient) mice compared with wild-type mice. Cellular analysis revealed continued neutrophil recruitment to the peritoneum and lungs of the NOX2-deficient mice and altered activation states of both neutrophils and macrophages. Histological examination showed multiple organ pathology indicative of MODS in the NOX2-deficient mice, and several inflammatory cytokines were elevated in lungs of the NOX2-deficient mice. Overall, these data suggest that NOX2 function protects against the development of MODS and is required for normal resolution of systemic inflammation. Copyright © 2014 the American Physiological Society.

  4. Simulation-optimization model of reservoir operation based on target storage curves

    Institute of Scientific and Technical Information of China (English)

    Hong-bin FANG; Tie-song HU; Xiang ZENG; Feng-yan WU

    2014-01-01

    This paper proposes a new storage allocation rule based on target storage curves. Joint operating rules are also proposed to solve the operation problems of a multi-reservoir system with joint demands and water transfer-supply projects. The joint operating rules include a water diversion rule to determine the amount of diverted water in a period, a hedging rule based on an aggregated reservoir to determine the total release from the system, and a storage allocation rule to specify the release from each reservoir. A simulation-optimization model was established to optimize the key points of the water diversion curves, the hedging rule curves, and the target storage curves using the improved particle swarm optimization (IPSO) algorithm. The multi-reservoir water supply system located in Liaoning Province, China, including a water transfer-supply project, was employed as a case study to verify the effectiveness of the proposed join operating rules and target storage curves. The results indicate that the proposed operating rules are suitable for the complex system. The storage allocation rule based on target storage curves shows an improved performance with regard to system storage distribution.

  5. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel N. Clark

    2006-12-31

    Nitric oxide (NO) and nitrogen dioxide (NO2) generated by internal combustion (IC) engines are implicated in adverse environmental and health effects. Even though lean-burn natural gas engines have traditionally emitted lower oxides of nitrogen (NOx) emissions compared to their diesel counterparts, natural gas engines are being further challenged to reduce NOx emissions to 0.1 g/bhp-hr. The Selective NOx Recirculation (SNR) approach for NOx reduction involves cooling the engine exhaust gas and then adsorbing the NOx from the exhaust stream, followed by the periodic desorption of NOx. By sending the desorbed NOx back into the intake and through the engine, a percentage of the NOx can be decomposed during the combustion process. SNR technology has the support of the Department of Energy (DOE), under the Advanced Reciprocating Engine Systems (ARES) program to reduce NOx emissions to under 0.1 g/bhp-hr from stationary natural gas engines by 2010. The NO decomposition phenomenon was studied using two Cummins L10G natural gas fueled spark-ignited (SI) engines in three experimental campaigns. It was observed that the air/fuel ratio ({lambda}), injected NO quantity, added exhaust gas recirculation (EGR) percentage, and engine operating points affected NOx decomposition rates within the engine. Chemical kinetic model predictions using the software package CHEMKIN were performed to relate the experimental data with established rate and equilibrium models. The model was used to predict NO decomposition during lean-burn, stoichiometric burn, and slightly rich-burn cases with added EGR. NOx decomposition rates were estimated from the model to be from 35 to 42% for the lean-burn cases and from 50 to 70% for the rich-burn cases. The modeling results provided an insight as to how to maximize NOx decomposition rates for the experimental engine. Results from this experiment along with chemical kinetic modeling solutions prompted the investigation of rich-burn operating conditions

  6. Accounting for Long Term Sediment Storage in a Watershed Scale Numerical Model for Suspended Sediment Routing

    Science.gov (United States)

    Keeler, J. J.; Pizzuto, J. E.; Skalak, K.; Karwan, D. L.; Benthem, A.; Ackerman, T. R.

    2015-12-01

    Quantifying the delivery of suspended sediment from upland sources to downstream receiving waters is important for watershed management, but current routing models fail to accurately represent lag times in delivery resulting from sediment storage. In this study, we route suspended sediment tagged by a characteristic tracer using a 1-dimensional model that implicitly includes storage and remobilization processes and timescales. From an input location where tagged sediment is added, the model advects suspended sediment downstream at the velocity of the stream (adjusted for the intermittency of transport events). Deposition rates are specified by the fraction of the suspended load stored per kilometer of downstream transport (presumably available from a sediment budget). Tagged sediment leaving storage is evaluated from a convolution equation based on the probability distribution function (pdf) of sediment storage waiting times; this approach avoids the difficulty of accurately representing complex processes of sediment remobilization from floodplain and other deposits. To illustrate the role of storage on sediment delivery, we compare exponential and bounded power-law waiting time pdfs with identical means of 94 years. In both cases, the median travel time for sediment to reach the depocenter in fluvial systems less than 40km long is governed by in-channel transport and is unaffected by sediment storage. As the channel length increases, however, the median sediment travel time reflects storage rather than in-channel transport; travel times do not vary significantly between the two different waiting time functions. At distances of 50, 100, and 200 km, the median travel time for suspended sediment is 36, 136, and 325 years, orders of magnitude slower than travel times associated with in-channel transport. These computations demonstrate that storage can be neglected for short rivers, but for longer systems, storage controls the delivery of suspended sediment.

  7. New model for holographic storage by simultaneous angular multiplexing

    Science.gov (United States)

    Ibarra, J. C.; Urzua, D.; Olivares-Peréz, A.; Ortiz-Gutierrez, M.

    2006-05-01

    We describe a technique for holographic storage by simultaneous angular multiplexing to obtain a large-scale holographic memory. We recorded 72 objects at the same time in one point on holographic plate PFG-03M from Slavich Co., using a He-Ne laser (λ = 633 nm). Each object is placed on a circular photographic transparency, separate 0.94 degree each one. The technique allows us simultaneous reconstruction of the 72 images without cross-talk. The diffraction efficiency obtained at order one is 6%. Experimental results are shown.

  8. Muninn: A versioning flash key-value store using an object-based storage model

    OpenAIRE

    Kang, Y.; Pitchumani, R; Marlette, T; Miller, El

    2014-01-01

    While non-volatile memory (NVRAM) devices have the po-tential to alleviate the trade-off between performance, scal-ability, and energy in storage and memory subsystems, a block interface and storage subsystems designed for slow I/O devices make it difficult to efficiently exploit NVRAMs in a portable and extensible way. We propose an object-based storage model as a way of addressing the shortfalls of the current interfaces. Through the design of Muninn, an object-based versioning key-value st...

  9. Thermal performance sensitivity studies in support of material modeling for extended storage of used nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Cuta, Judith M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Suffield, Sarah R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fort, James A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adkins, Harold E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-08-15

    The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.

  10. Nox reduction in the sintering process

    Institute of Scientific and Technical Information of China (English)

    Yan-guang Chen; Zhan-cheng Guo; Zhi Wang; Gen-sheng Feng

    2009-01-01

    A new process, NOx reduction with recycling flue gas and modifying coke breeze, was proposed. The effects of modified coke breeze and recycled flue gas on NOx reduction were investigated by sinter pot tests. The results show that the NOx reduction rate is over 10wt% in the sintering of modified coke breeze, the effects of the additives on NOx reduction are: CeO2CaOK2CO3.The NOx reduction rate increases with the amount of recycled flue gas, and is 22.35wt% in the sintering with recycling 30vo1% of the flue gas. When 30vo1% of the flue gas is recycled into the sintering of CeO2, CaO, and K2CO3 modified coke breeze, the NOx reduc-tion rates are 36.10wt%, 32.56wt%, and 32.17wt%, respectively.

  11. State of the art coal fired steam generators for low emission of CO{sub 2}, SO{sub 2}, and NOx

    Energy Technology Data Exchange (ETDEWEB)

    Busekrus, K.; Tigges, K.; Klauke, F. [Hitachi Power Europe GmbH (Germany)

    2008-07-01

    Some methods of improving efficiency of coal-fired power plants in order to reduce CO{sub 2} emissions is described, followed by carbon capture and storage technologies. NOx and SOx reduction technologies are then discussed. 26 refs.

  12. Modeling and Operational Testing of an Isolated Variable Speed PMSG Wind Turbine with Battery Energy Storage

    Directory of Open Access Journals (Sweden)

    BAROTE, L.

    2012-05-01

    Full Text Available This paper presents the modeling and operational testing of an isolated permanent magnet synchronous generator (PMSG, driven by a small wind turbine with a battery energy storage system during wind speed and load variations. The whole system is initially modeled, including the PMSG, the boost converter and the storage system. The required power for the connected loads can be effectively delivered and supplied by the proposed wind turbine and energy storage systems, subject to an appropriate control method. Energy storage devices are required for power balance and power quality in stand alone wind energy systems. The main purpose is to supply 230 V / 50 Hz domestic appliances through a single-phase inverter. The experimental waveforms, compared to the simulation results, show a good prediction of the electrical variable parameters. Furthermore, it can be seen that the results validate the stability of the supply.

  13. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2005-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  14. A Novel Modeling of Molten-Salt Heat Storage Systems in Thermal Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Rogelio Peón Menéndez

    2014-10-01

    Full Text Available Many thermal solar power plants use thermal oil as heat transfer fluid, and molten salts as thermal energy storage. Oil absorbs energy from sun light, and transfers it to a water-steam cycle across heat exchangers, to be converted into electric energy by means of a turbogenerator, or to be stored in a thermal energy storage system so that it can be later transferred to the water-steam cycle. The complexity of these thermal solar plants is rather high, as they combine traditional engineering used in power stations (water-steam cycle or petrochemical (oil piping, with the new solar (parabolic trough collector and heat storage (molten salts technologies. With the engineering of these plants being relatively new, regulation of the thermal energy storage system is currently achieved in manual or semiautomatic ways, controlling its variables with proportional-integral-derivative (PID regulators. This makes the overall performance of these plants non optimal. This work focuses on energy storage systems based on molten salt, and defines a complete model of the process. By defining such a model, the ground for future research into optimal control methods will be established. The accuracy of the model will be determined by comparing the results it provides and those measured in the molten-salt heat storage system of an actual power plant.

  15. Modeling Potential Surface and Shallow Groundwater Storage Provided by Beaver Ponds Across Watersheds

    Science.gov (United States)

    Hafen, K.; Wheaton, J. M.; Macfarlane, W.

    2016-12-01

    Damming of streams by North American Beaver (Castor canadensis) has been shown to provide a host of potentially desirable hydraulic and hydrologic impacts. Notably, increases in surface water storage and groundwater storage may alter the timing and delivery of water around individual dams and dam complexes. Anecdotal evidence suggests these changes may be important for increasing and maintaining baseflow and even helping some intermittent streams flow perennially. In the arid west, these impacts could be particularly salient in the face of climate change. However, few studies have examined the hydrologic impacts of beaver dams at scales large enough to provide insight for water management, in part because understanding or modeling these impacts at large spatial scales has been precluded by uncertainty concerning the number of beaver dams a drainage network can support. Using the recently developed Beaver Restoration Assessment Tool (BRAT) to identify possible densities and spatial configurations of beaver dams, we developed a model that predicts the area and volume of surface water storage associated with dams of various sizes, and applied this model at different dam densities across multiple watersheds (HUC12) in northern Utah. We then used model results as inputs to the MODFLOW groundwater model to identify the subsequent changes to shallow groundwater storage. The spatially explicit water storage estimates produced by our approach will be useful in evaluating potential beaver restoration and conservation, and will also provide necessary information for developing hydrologic models to specifically identify the effects beaver dams may have on water delivery and timing.

  16. Development and Validation of a Slurry Model for Chemical Hydrogen Storage in Fuel Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Kriston P.; Pires, Richard P.; Simmons, Kevin L.

    2014-07-25

    The US Department of Energy's (DOE) Hydrogen Storage Engineering Center of Excellence (HSECoE) is developing models for hydrogen storage systems for fuel cell-based light duty vehicle applications for a variety of promising materials. These transient models simulate the performance of the storage system for comparison to the DOE’s Technical Targets and a set of four drive cycles. The purpose of this research is to describe the models developed for slurry-based chemical hydrogen storage materials. The storage systems of both a representative exothermic system based on ammonia borane and endothermic system based on alane were developed and modeled in Simulink®. Once complete the reactor and radiator components of the model were validated with experimental data. The model was then run using a highway cycle, an aggressive cycle, cold-start cycle and hot drive cycle. The system design was adjusted to meet these drive cycles. A sensitivity analysis was then performed to identify the range of material properties where these DOE targets and drive cycles could be met. Materials with a heat of reaction greater than 11 kJ/mol H2 generated and a slurry hydrogen capacity of greater than 11.4% will meet the on-board efficiency and gravimetric capacity targets, respectively.

  17. Development and validation of a slurry model for chemical hydrogen storage in fuel cell vehicle applications

    Science.gov (United States)

    Brooks, Kriston P.; Pires, Richard P.; Simmons, Kevin L.

    2014-12-01

    The U.S. Department of Energy's (DOE) Hydrogen Storage Engineering Center of Excellence (HSECoE) is developing models for hydrogen storage systems for fuel cell-based light duty vehicle applications for a variety of promising materials. These transient models simulate the performance of the storage system for comparison to the DOE's Technical Targets and a set of four drive cycles. PNNL developed models to simulate the performance and suitability of slurry-based chemical hydrogen storage materials. The storage systems of both a representative exothermic system based on ammonia borane and an endothermic system based on alane were developed and modeled in Simulink®. Once complete, the reactor and radiator components of the model were validated with experimental data. The system design parameters were adjusted to allow the model to successfully meet a highway cycle, an aggressive cycle, a cold-start cycle, and a hot drive cycle. Finally, a sensitivity analysis was performed to identify the range of material properties where these DOE targets and drive cycles could be met. Materials with a heat of reaction >11 kJ mol-1 H2 generated and a slurry hydrogen capacity of >11.4% will meet the on-board efficiency and gravimetric capacity targets, respectively.

  18. Importance of NOx control for peak ozone reduction in the Pearl River Delta region

    Science.gov (United States)

    Li, Ying; Lau, Alexis K. H.; Fung, Jimmy C. H.; Zheng, Junyu; Liu, Shawchen

    2013-08-01

    As major air pollutants and key precursors of several secondary air pollutants, nitrogen oxide (NOx) emissions are regulated in many countries. However, NOx control increases ozone concentrations when the ozone formation regime is volatile organic compound (VOC) limited. Although many studies have shown that NOx regulation reduces ozone levels over the long term, it is still of concern that NOx regulation increases short-term ozone levels in metropolitan regions, where ozone formation is found to be predominantly VOC-limited. The Pearl River Delta (PRD) in China is such a region. Our modeling sensitivity study shows that while NOx reduction in the PRD region may raise the mean ozone concentration, it can also decrease peak ozone levels. Similar changes are observed in the NOx and ozone data of the PRD regional air quality monitoring network (2006-2012), lending further credence to our results. In the model, this NOx control effect is a result of the complicated spatial and diurnal variations of the ozone formation regime. In most of the PRD region, the formation regime is VOC-limited in the morning and becomes NOx-limited during peak ozone hours. Although some areas are always VOC-limited, their ozone concentrations are relatively low, and the ozone increases caused by NOx reduction generally do not cause higher ozone levels than the region's original ozone maxima. Several control scenarios are simulated to evaluate the effects of various possible control regulations. Our results show that in addition to VOC control, NOx control can be effective for reducing peak ozone concentrations in the PRD region.

  19. Data organization and storage model of the realty uniform registration system

    Science.gov (United States)

    Shen, Chenhua; Liu, Yu; Wu, Xiaobin

    2007-06-01

    Based on the Real Right Law, this article analyzes the entity objects of the realty uniform registration, and establishes the model of the logical relations among the entities, from which the dada relation model is proposed, and from which the data relation model of the realty uniform registration is proposed, and is compared with the current land registration data model and the real estate data model. It is proved that this uniform registration data model has not only maintained the close links with the land registration data model and the real estate registration data model, but also met the need of the uniform registration by comparing with the existing land registration data model and the real estate data model. In the end, this article discusses the method of data storage for the uniform registration of the land and the real estate to improve the efficiency of storage and access by adopting split technology to store the alteration data logically.

  20. "Method, system and storage medium for generating virtual brick models"

    DEFF Research Database (Denmark)

    2009-01-01

    An exemplary embodiment is a method for generating a virtual brick model. The virtual brick models are generated by users and uploaded to a centralized host system. Users can build virtual models themselves or download and edit another user's virtual brick models while retaining the identity...... of the original virtual brick model. Routines are provided for both storing user created building steps in and generating automated building instructions for virtual brick models, generating a bill of materials for a virtual brick model and ordering physical bricks corresponding to a virtual brick model....

  1. Effects of biogenic nitrate chemistry on the NOx lifetime in remote continental regions

    Science.gov (United States)

    Browne, E. C.; Cohen, R. C.

    2012-12-01

    We present an analysis of the NOx budget in conditions of low NOx (NOx = NO + NO2) and high biogenic volatile organic compound (BVOC) concentrations that are characteristic of most continental boundary layers. Using a steady-state model, we show that below 500 pptv of NOx, the NOx lifetime is extremely sensitive to organic nitrate (RONO2) formation rates. We find that even for RONO2 formation values that are an order of magnitude smaller than is typical for continental conditions significant reductions in NOx lifetime, and consequently ozone production efficiency, are caused by nitrate forming reactions. Comparison of the steady-state box model to a 3-D chemical transport model (CTM) confirms that the concepts illustrated by the simpler model are a useful approximation of predictions provided by the full CTM. This implies that the regional and global budgets of NOx, OH, and ozone will be sensitive to assumptions regarding organic nitrate chemistry. Changes in the budgets of these species affect the representation of processes important to air quality and climate. Consequently, CTMs must include an accurate representation of organic nitrate chemistry in order to provide accurate assessments of past, present, and future air quality and climate. These findings suggest the need for further experimental constraints on the formation and fate of biogenic RONO2.

  2. Dynamics for the storage control of a endocrine gland: A model for adrenal epinephrine

    Science.gov (United States)

    Cortez, Celia Martins; Neto, Antonio Pires; Motta, Art Adriel E. A.

    2016-12-01

    In this work, we are presenting a simple mathematical model to simulate the control dynamics of synthesis, storage and secretion in an endocrine gland. In this, the hormone normally is synthetized from material selected and removed from the blood. In cell, material is processed and the final product, the hormone, can be stored until being released to the blood. The model associates the classical theory enzymatic kinetics to Lotka-Volterra equations. To test the proposed model, we take as an example the regulation of catecholamine synthesis-storage-release in the adrenal medulla.

  3. Energy Storage in Power System Operation: The Power Nodes Modeling Framework

    DEFF Research Database (Denmark)

    Heussen, Kai; Koch, Stephan; Ulbig, Andreas

    2010-01-01

    such as power rating, ramprate constraints, eciencies, and storage capacity are modeled, while the individual physical properties of the interconnected units are not taken into account. This allows the modeling of a physically very diverse unit portfolio with a single approach. The concept can be used...... for designing operation strategies for power systems based on ubiquitous energy storage, for example to buer non-dispatchable generation, as well as for the evaluation of the operational performance in terms of energy eciency, reliability and cost. After introducing the modeling approach and a categorization...

  4. A model of cloud application assignments in software-defined storages

    Science.gov (United States)

    Bolodurina, Irina P.; Parfenov, Denis I.; Polezhaev, Petr N.; Shukhman, Alexander E.

    2017-01-01

    The aim of this study is to analyze the structure and mechanisms of interaction of typical cloud applications and to suggest the approaches to optimize their placement in storage systems. In this paper, we describe a generalized model of cloud applications including the three basic layers: a model of application, a model of service, and a model of resource. The distinctive feature of the model suggested implies analyzing cloud resources from the user point of view and from the point of view of a software-defined infrastructure of the virtual data center (DC). The innovation character of this model is in describing at the same time the application data placements, as well as the state of the virtual environment, taking into account the network topology. The model of software-defined storage has been developed as a submodel within the resource model. This model allows implementing the algorithm for control of cloud application assignments in software-defined storages. Experimental researches returned this algorithm decreases in cloud application response time and performance growth in user request processes. The use of software-defined data storages allows the decrease in the number of physical store devices, which demonstrates the efficiency of our algorithm.

  5. Comparative Heat Conduction Model of a Cold Storage with Puf & Eps Insulation Using Taguchi Methodology

    Directory of Open Access Journals (Sweden)

    Dr. N. Mukhopadhyay

    2015-05-01

    Full Text Available In this project work a mathematical heat conduction model of a cold storage (with the help of computer program; and multiple regression analysis has been proposed which can be used for further development of cold storages in the upcoming future. In cold storage refrigeration system brings down the temperature initially during start up but thermal insulation maintains the temperature later on continuously. In this view, the simple methodology is presented to calculate heat transfer by analytical method also attempt has been made to minimize the energy consumption by replacing 150 mm Expanded polystyrene (EPS by 100 mm Poly Urethane foam (PUF insulation. The methodology is validated against actual data obtained from Penguin cold storage situated in Pune, India. Insulation thickness of the side walls (TW, area of the wall (AW, and insulation thickness of the roof (TR have been chosen as predictor variables of the study.

  6. A numerical model for thermal energy storage systems utilising encapsulated phase change materials

    Science.gov (United States)

    Jacob, Rhys; Saman, Wasim; Bruno, Frank

    2016-05-01

    In an effort to reduce the cost of thermal energy storage for concentrated solar power plants, a thermocline storage concept was investigated. Two systems were investigated being a sensible-only and an encapsulated phase change system. Both systems have the potential to reduce the storage tank volume and/or reduce the cost of the filler material, thereby reducing the cost of the system when compared to current two-tank molten salt systems. The objective of the current paper is to create a numerical model capable of designing and simulating the aforementioned thermocline storage concepts in the open source programming language known as Python. The results of the current study are compared to previous numerical results and are found to be in good agreement.

  7. [Prediction of spatial distribution of forest carbon storage in Heilongjiang Province using spatial error model].

    Science.gov (United States)

    Liu, Chang; Li, Feng-Ri; Zhen, Zhen

    2014-10-01

    Abstract: Based on the data from Chinese National Forest Inventory (CNFI) and Key Ecological Benefit Forest Monitoring plots (5075 in total) in Heilongjiang Province in 2010 and concurrent meteorological data coming from 59 meteorological stations located in Heilongjiang, Jilin and Inner Mongolia, this paper established a spatial error model (SEM) by GeoDA using carbon storage as dependent variable and several independent variables, including diameter of living trees (DBH), number of trees per hectare (TPH), elevation (Elev), slope (Slope), and product of precipitation and temperature (Rain_Temp). Global Moran's I was computed for describing overall spatial autocorrelations of model results at different spatial scales. Local Moran's I was calculated at the optimal bandwidth (25 km) to present spatial distribution residuals. Intra-block spatial variances were computed to explain spatial heterogeneity of residuals. Finally, a spatial distribution map of carbon storage in Heilongjiang was visualized based on predictions. The results showed that the distribution of forest carbon storage in Heilongjiang had spatial effect and was significantly influenced by stand, topographic and meteorological factors, especially average DBH. SEM could solve the spatial autocorrelation and heterogeneity well. There were significant spatial differences in distribution of forest carbon storage. The carbon storage was mainly distributed in Zhangguangcai Mountain, Xiao Xing'an Mountain and Da Xing'an Mountain where dense, forests existed, rarely distributed in Songnen Plains, while Wanda Mountain had moderate-level carbon storage.

  8. Nox4 Is Expressed In Pulmonary Artery Adventitia And Contributes To Hypertensive Vascular Remodeling

    Science.gov (United States)

    Barman, Scott A.; Chen, Feng; Su, Yunchao; Dimitropoulou, Christiana; Wang, Yusi; Catravas, John D.; Han, Weihong; Orfi, Laszlo; Szantai-Kis, Csaba; Keri, Gyorgy; Szabadkai, Istvan; Barabutis, Nektarios; Rafikova, Olga; Rafikov, Ruslan; Black, Stephen M.; Jonigk, Danny; Giannis, Athanassios; Asmis, Reto; Stepp, David W.; Ramesh, Ganesan; Fulton, David J.R.

    2014-01-01

    OBJECTIVE Pulmonary Hypertension (PH) is a progressive disease arising from remodeling and narrowing of pulmonary arteries (PA) resulting in high pulmonary blood pressure and ultimately right ventricular failure. Elevated production of reactive oxygen species (ROS) by NADPH oxidase 4 (Nox4) is associated with increased pressure in PH. However, the cellular location of Nox4 and its contribution to aberrant vascular remodeling in PH remains poorly understood. Therefore, we sought to identify the vascular cells expressing Nox4 in PA and determine the functional relevance of Nox4 in PH. APPROACH AND RESULTS Elevated expression of Nox4 was detected in hypertensive PA from 3 rat PH models and human PH using qRT-PCR, Western blot, and immunofluorescence. In the vascular wall, Nox4 was detected in both endothelium and adventitia and perivascular staining was prominently increased in hypertensive lung sections, colocalizing with cells expressing fibroblast and monocyte markers and matching the adventitial location of ROS production. Small molecule inhibitors of Nox4 reduced adventitial ROS generation and vascular remodeling as well as ameliorating right ventricular hypertrophy and non-invasive indices of PA stiffness in monocrotaline (MCT)-treated rats as determined by morphometric analysis and high resolution digital ultrasound. Nox4 inhibitors improved PH in both prevention and reversal protocols and reduced the expression of fibroblast markers in isolated PA. In fibroblasts, Nox4 over-expression stimulated migration and proliferation and was necessary for matrix gene expression. CONCLUSIONS These findings indicate that Nox4 is prominently expressed in the adventitia and contributes to altered fibroblast behavior, hypertensive vascular remodeling and the development of PH. PMID:24947524

  9. The hillslope-storage Boussinesq model for non-constant bedrock slope

    NARCIS (Netherlands)

    Hilberts, A.G.J.; Loon, van E.E.; Troch, P.A.A.; Paniconi, C.

    2004-01-01

    In this study the recently introduced hill slope-storage Boussinesq (hsB) model is cast in a generalized formulation enabling the model to handle non-constant bedrock slopes (i.e. bedrock profile curvature). This generalization extends the analysis of hydrological behavior to hillslopes of arbitrary

  10. The benefits of gravimeter observations for modelling water storage changes at the field scale

    Directory of Open Access Journals (Sweden)

    B. Creutzfeldt

    2010-04-01

    Full Text Available Water storage is the fundamental state variable of hydrological systems. However, comprehensive data on total water storage changes (WSC are practically inaccessible by hydrological measurement techniques at the field or catchment scale, and hydrological models are highly uncertain in representing the storage term due to the lack of adequate validation or calibration data. In this study, we assess the benefit of temporal gravimeter measurements for modelling WSC at the field scale. A simple conceptual hydrological model is calibrated and evaluated against records of a superconducting gravimeter, soil moisture and groundwater time series. The model is validated against independently estimated WSC data. Using gravimeter data as a calibration constraint improves the model results substantially in terms of predictive capability and variation of the behavioural model runs. Thanks to their capacity to integrate over different storage components and a larger area, gravimeters provide generalised information on total WSC that is useful to constrain the overall status of the hydrological system in a model. The general problem of specifying the internal model structure or individual parameter sets can, however, not be solved with gravimeters alone.

  11. A PROBABILISTIC INVENTORY MODEL FOR CONDITIONAL CREDIT PERIOD AND LEAD TIME WITH MULTIPLE STORAGE FACILITIES

    Directory of Open Access Journals (Sweden)

    S. S. Mishra

    2008-01-01

    Full Text Available A probabilistic inventory model for conditional credit period with exponential demand, non-zero lead time and multiple storage facility has been developed. The behaviour of total expected cost (TEC has been examined and the use and application of the model is demonstrated with the help of a numerical example.

  12. A predictive model for smart control of a domestic heat pump and thermal storage

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; Gebhardt, I.; de Wit, J.B.; Smit, Gerardus Johannes Maria

    The purpose of this paper is to develop and validate a predictive model of a thermal storage which is charged by a heat pump and used for domestic hot water supply. The model is used for smart grid control purposes and requires measurement signals of flow and temperature at the inlet and outlet of

  13. A predictive model for smart control of a domestic heat pump and thermal storage

    NARCIS (Netherlands)

    Leeuwen, van R.P.; Gebhardt, I.; Wit, de J.B.; Smit, G.J.M.

    2016-01-01

    The purpose of this paper is to develop and validate a predictive model of a thermal storage which is charged by a heat pump and used for domestic hot water supply. The model is used for smart grid control purposes and requires measurement signals of flow and temperature at the inlet and outlet of t

  14. Research on Mechanism and Model of Centralized Bidding for Pumped Storage Power in Shanghai

    Science.gov (United States)

    Hua, Zhong; Ying, Zhiwei; Lv, Zhengyu; Jianlin, Yang; Huang, Yupeng; Li, Dong

    2017-05-01

    China is now in the transition stage toward power market and in some specific area, market approach has already been adopted to improve the overall efficiency. In this paper, Bidding and trading modes of pumped storage energy in various regions of China are analysed. Based on the constraints of bidding price and electricity, as well as the system power flow, the trading model is established to collect the capacity cost of pumped storage energy in Shanghai. With the trading model proposed, that the generators who actively undertake the capacity cost of pumped storage energy and bid enough electricity with lower price can be rewarded, while those attempts to conspire and manipulate the market will be penalized. Finally, using seven generators in Shanghai as examples to simulate the market operation, the effectiveness of the proposed model is verified.

  15. Removal of NOx by radical injection

    Institute of Scientific and Technical Information of China (English)

    LIN He; GAO Xiang; LUO Zhongyang; CEN Kefa; PEI Meixiang; HUANG Zhen

    2004-01-01

    Removal of NOx ( DeNOx, NOx is the total of NO and NO2) from flue gas by radical injection has been investigated . The discharge characteristics were examined and the steady streamer corona was acquired by adjusting the nozzle gases properly. It was found that an increase in the voltage resulted in a decrease in the NO concentration and the concentration of the NO2 increased at low voltages but decreased as the voltage rose to a certain level. The DeNOx efficiency increased as the applied voltage rose and reached a maximum of 70% when the voltage approached the breakdown voltage. The hypothetical mechanism of NOx removal suggested that the radicals formed in the discharge process converted the NO and NO2 into acidic species. The Monte Carlo method was used to calculate the rate coefficients and the productivity of the radicals, and then the concentrations of both NO and NO2 and the DeNOx efficiencies were calculated with chemical kinetics. The calculated DeNOx efficiencies were comparable with the experimental DeNOx efficiencies at low voltages, but were lower at high voltages.

  16. Modeling of an Integrated Renewable Energy System (IRES) with hydrogen storage

    Science.gov (United States)

    Shenoy, Navin Kodange

    2010-12-01

    Scope and Method of Study. The purpose of the study was to consider the integration of hydrogen storage technology as means of energy storage with renewable sources of energy. Hydrogen storage technology consists of an alkaline electrolyzer, gas storage tank and a fuel cell. The Integrated Renewable Energy System (IRES) under consideration includes wind energy, solar energy from photovoltaics, solar thermal energy and biomass energy in the form of biogas. Energy needs are categorized depending on the type and quality of the energy requirements. After meeting all the energy needs, any excess energy available from wind and PVs is converted into hydrogen using an electrolyzer for later use in a fuel cell. Similarly, when renewable energy generation is not able to supply the actual load demand, the stored hydrogen is utilized through fuel cell to fulfill load demand. Analysis of how IRES operates in order to satisfy different types of energy needs is discussed. Findings and Conclusions. All simulations are performed using MATLAB software. Hydrogen storage technology consisting of an electrolyzer, gas storage tank and a fuel cell is incorporated in the IRES design process for a hypothetical remote community. Results show that whenever renewable energy generated is greater than the electrical demand, excess energy is stored in the form of hydrogen and in case of energy shortfall, the stored hydrogen is utilized through the fuel cell to supply to excess power demand. The overall operation of IRES is enhanced as a result of energy storage in the form of hydrogen. Hydrogen has immense potential to be the energy carrier of the future because of its clean character and the model of hydrogen storage discussed here can form an integral part of IRES for remote area applications.

  17. Implications of the modelling of stratified hot water storage tanks in the simulation of CHP plants

    Energy Technology Data Exchange (ETDEWEB)

    Campos Celador, A., E-mail: alvaro.campos@ehu.es [ENEDI Research Group-University of the Basque Country, Departamento de Maquinas y Motores Termicos, E.T.S.I. de Bilbao Alameda de Urquijo, s/n 48013 Bilbao, Bizkaia (Spain); Odriozola, M.; Sala, J.M. [ENEDI Research Group-University of the Basque Country, Departamento de Maquinas y Motores Termicos, E.T.S.I. de Bilbao Alameda de Urquijo, s/n 48013 Bilbao, Bizkaia (Spain)

    2011-08-15

    Highlights: {yields} Three different modelling approaches for simulation of hot water tanks are presented. {yields} The three models are simulated within a residential cogeneration plant. {yields} Small differences in the results are found by an energy and exergy analysis. {yields} Big differences between the results are found by an advanced exergy analysis. {yields} Results on the feasibility study are explained by the advanced exergy analysis. - Abstract: This paper considers the effect that different hot water storage tank modelling approaches have on the global simulation of residential CHP plants as well as their impact on their economic feasibility. While a simplified assessment of the heat storage is usually considered in the feasibility studies of CHP plants in buildings, this paper deals with three different levels of modelling of the hot water tank: actual stratified model, ideal stratified model and fully mixed model. These three approaches are presented and comparatively evaluated under the same case of study, a cogeneration plant with thermal storage meeting the loads of an urbanisation located in the Bilbao metropolitan area (Spain). The case of study is simulated by TRNSYS for each one of the three modelling cases and the so obtained annual results are analysed from both a First and Second-Law-based viewpoint. While the global energy and exergy efficiencies of the plant for the three modelling cases agree quite well, important differences are found between the economic results of the feasibility study. These results can be predicted by means of an advanced exergy analysis of the storage tank considering the endogenous and exogenous exergy destruction terms caused by the hot water storage tank.

  18. Power Systems and Energy Storage Modeling for Directed Energy Weapons

    Science.gov (United States)

    2014-06-01

    electron laser kW Kilo-watt LCS Littoral Combat Ship LAWS Laser Weapon System MLD Maritime Laser Demonstration MW Mega -watt NiMH Nickel metal...and various littoral combat ships. Also, an accurate, working model of the capacitor energy bank is being developed and the flywheel model is being

  19. Evaluation of NOx emission inventories in California using multi-satellite data sets, AMAX-DOAS and in-situ airborne measurements, and regional model simulations during the CalNex field campaign

    Science.gov (United States)

    Kim, S.; Baidar, S.; Boersma, F.; Brioude, J. F.; Bucsela, E. J.; Burrows, J. P.; Celarier, E. A.; Cohen, R. C.; Frost, G. J.; Harley, R. A.; Krotkov, N. A.; Lamsal, L. N.; Martin, R.; Mcdonald, B. C.; McKeen, S. A.; Oetjen, H.; Pollack, I. B.; Richter, A.; Russell, A.; Ryerson, T. B.; Trainer, M.; Valin, L. C.; Volkamer, R.

    2013-12-01

    Satellite NO2 column measurements indicate large NOx emissions from urban and agricultural sources in California. Comparison of regional model-simulated NO2 columns with satellite retrievals has proven useful in evaluating emission inventories for various sectors. We compare the NO2 columns from the WRF-Chem model with the multi-satellite data sets from different instruments and retrieval groups for a variety of California sources. Use of multiple satellite data sets help to define the uncertainties in the satellite retrievals. In addition, the CalNex 2010 intensive field campaign provides a unique opportunity to independently assess California's emission inventories. CU-AMAX-DOAS and in-situ airborne observations from CalNex 2010 and fine-resolution model simulations are used to estimate the accuracy of the satellite NO2 column retrievals over urban and agricultural areas. To understand differences in the retrievals, we will present sensitivity of satellite NO2 retrievals to a priori NO2 profiles that are produced from global models and the fine-resolution WRF-Chem model using state-of-the-art emission inventories.

  20. Critical review of creep FRAPCON-3 model under dry storage conditions

    Energy Technology Data Exchange (ETDEWEB)

    Feria, F.; Herranz, L.E. [Unit of Nuclear Safety Research, CIEMAT, Avda. Complutense 22, Madrid, Madrid 28040 (Spain)

    2009-06-15

    There is a general agreement that cladding creep rupture is the most likely and limiting failure mechanism of spent fuel in dry storage compared to other potential mechanisms, like stress corrosion cracking and/or delayed hydride cracking. Nevertheless, occurrence of creep rupture is very improbable since both decay heat and hoop stress tend to decrease throughout dry storage. In spite of this, the current trend to higher burn up levels needs further attention that ensures safe storage of spent fuel irradiated over 45 GWd/MTU. An extensive work has been carried out during the last four decades in the area of in-reactor creep modelling. Unfortunately, the in-reactor conditions are so different from those prevailing under dry storage, that all the experience gained cannot be extrapolated in a straightforward manner. On the other side, as creep tests simulating conditions throughout a 20-40 year dry storage are impractical, post-irradiation cladding creep behaviour has been modelled by means of time-temperature dependent laws developed on the basis of currently available zirconium alloys data. Additionally, some tests have been exploring the effect of irradiation, hydrogen distribution and material composition on the materials creep behaviour. Adaptation of fuel performance codes initially developed for normal and off-normal reactor operation is not an easy task either. Creep modelling is usually dependent of host codes because a good part of its validation and update has been carried out in an integral way, and as a consequence its independent performance assessment is not an easy task. This work examines the current capability of FRAPCON-3 to model creep behaviour under dry storage conditions. To do so, a review of its major fundamentals has been done and its range of applicability discussed. Once its main approximations and drawbacks have been identified, an attempt to overcome some of them has been intended by implementing an alternative expression for creep under

  1. Simulation model for wind energy storage systems. Volume II. Operation manual. [SIMWEST code

    Energy Technology Data Exchange (ETDEWEB)

    Warren, A.W.; Edsinger, R.W.; Burroughs, J.D.

    1977-08-01

    The effort developed a comprehensive computer program for the modeling of wind energy/storage systems utilizing any combination of five types of storage (pumped hydro, battery, thermal, flywheel and pneumatic). An acronym for the program is SIMWEST (Simulation Model for Wind Energy Storage). The level of detail of SIMWEST is consistent with a role of evaluating the economic feasibility as well as the general performance of wind energy systems. The software package consists of two basic programs and a library of system, environmental, and load components. Volume II, the SIMWEST operation manual, describes the usage of the SIMWEST program, the design of the library components, and a number of simple example simulations intended to familiarize the user with the program's operation. Volume II also contains a listing of each SIMWEST library subroutine.

  2. A model for release of fission products from a breached fuel plate under wet storage

    Energy Technology Data Exchange (ETDEWEB)

    Terremoto, L.A.A.; Seerban, R.S.; Zeituni, C.A.; Silva, J.E.R. da; Silva, A.T. e; Castanheira, M.; Lucki, G.; Damy, M. de A.; Teodoro, C.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: laaterre@ipen.br

    2007-07-01

    MTR fuel elements burned-up inside the core of nuclear research reactors are stored worldwide mainly under the water of storage pools. When cladding breach is present in one or more fuel plates of such elements, radioactive fission products are released into the storage pool water. This work proposes a model to describe the release mechanism considering the diffusion of nuclides of a radioactive fission product either through a postulated small cylindrical breach or directly from a large circular hole in the cladding. In each case, an analytical expression is obtained for the activity released into the water as a function of the total storage time of a breached fuel plate. Regarding sipping tests already performed at the IEA-R1 research reactor on breached MTR fuel elements, the proposed model correlates successfully the specific activity of {sup 137}Cs, measured as a function of time, with the evaluated size of the cladding breach. (author)

  3. Utility-Scale Lithium-Ion Storage Cost Projections for Use in Capacity Expansion Models

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Wesley J.; Marcy, Cara; Krishnan, Venkat K.; Margolis, Robert

    2016-11-21

    This work presents U.S. utility-scale battery storage cost projections for use in capacity expansion models. We create battery cost projections based on a survey of literature cost projections of battery packs and balance of system costs, with a focus on lithium-ion batteries. Low, mid, and high cost trajectories are created for the overnight capital costs and the operating and maintenance costs. We then demonstrate the impact of these cost projections in the Regional Energy Deployment System (ReEDS) capacity expansion model. We find that under reference scenario conditions, lower battery costs can lead to increased penetration of variable renewable energy, with solar photovoltaics (PV) seeing the largest increase. We also find that additional storage can reduce renewable energy curtailment, although that comes at the expense of additional storage losses.

  4. Modeling long-term, large-scale sediment storage using a simple sediment budget approach

    Science.gov (United States)

    Naipal, Victoria; Reick, Christian; Van Oost, Kristof; Hoffmann, Thomas; Pongratz, Julia

    2016-05-01

    Currently, the anthropogenic perturbation of the biogeochemical cycles remains unquantified due to the poor representation of lateral fluxes of carbon and nutrients in Earth system models (ESMs). This lateral transport of carbon and nutrients between terrestrial ecosystems is strongly affected by accelerated soil erosion rates. However, the quantification of global soil erosion by rainfall and runoff, and the resulting redistribution is missing. This study aims at developing new tools and methods to estimate global soil erosion and redistribution by presenting and evaluating a new large-scale coarse-resolution sediment budget model that is compatible with ESMs. This model can simulate spatial patterns and long-term trends of soil redistribution in floodplains and on hillslopes, resulting from external forces such as climate and land use change. We applied the model to the Rhine catchment using climate and land cover data from the Max Planck Institute Earth System Model (MPI-ESM) for the last millennium (here AD 850-2005). Validation is done using observed Holocene sediment storage data and observed scaling between sediment storage and catchment area. We find that the model reproduces the spatial distribution of floodplain sediment storage and the scaling behavior for floodplains and hillslopes as found in observations. After analyzing the dependence of the scaling behavior on the main parameters of the model, we argue that the scaling is an emergent feature of the model and mainly dependent on the underlying topography. Furthermore, we find that land use change is the main contributor to the change in sediment storage in the Rhine catchment during the last millennium. Land use change also explains most of the temporal variability in sediment storage in floodplains and on hillslopes.

  5. SELECTIVE NOx RECIRCULATION FOR STATIONARY LEAN-BURN NATURAL GAS ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Chamila Tissera; Matt Swartz; Emre Tatli; Ramprabhu Vellaisamy

    2005-01-01

    the baseline and finding the ratio between the injected NO amounts. It was observed that the air/fuel ratio, injected NO quantity and engine operating points affected the NOx decomposition rates of the natural gas engine. A highest NOx decomposition rate of 27% was measured from this engine. A separate exploratory tests conducted with a gasoline engine with a low air/fuel ratio yielded results that suggested, that high NOx decomposition rates may be possible if a normally lean burn engine were operated at conditions closer to stoichiometric, with high exhaust gas recirculation (EGR) for a brief period of time during the NOx decomposition phase and with a wider range of air/fuel ratios. Chemical kinetic model predictions using CHEMKIN were performed to relate the experimental data with the established rate and equilibrium models. NOx decomposition rates from 35% to 42% were estimated using the CHEMKIN software. This provided insight on how to maximize NOx decomposition rates for a large bore engine. In the future, the modeling will be used to examine the effect of higher NO{sub 2}/NO ratios that are associated with lower speed and larger bore lean burn operation.

  6. Research on renewable energy power generation complementarity and storage distribution model

    Science.gov (United States)

    Wei, Xiaoxia; Zhang, Jinfang

    2017-01-01

    This paper mainly studied the equivalent conversion relationships and model of different “quality “energies in process of multi-energy conversion. In energy interconnection system containing wind turbine, photovoltaic cell and energy storage systems, it gives renewable energy and storage distribution development model, considering comprehensive effect of load demand characteristics on energy utilization mode, multi-objective optimization model is established with objectives of both maximized energy utilization ratio and minimized system operation costs. Then, take Chinese one certain area as scenario, and give out “renewable energy utilization“, “energy transfer” and “total operating cost” three different analyses, according to the connection model. The result is compared with that for traditional energy utilization model. Feasibility of the proposed model is verified with simulation results.

  7. Application of spatially varying storage capacity model for runoff parameterization in semi-arid catchment

    Institute of Scientific and Technical Information of China (English)

    Li-liang REN; Gui-zuo WANG; Fang LU; Tian-fang FANG

    2009-01-01

    This paper introduces the method of designation of water storage capacity for each grid cell within a catchment, which considers topography, vegetation and soil synthetically. For the purpose of hydrological process simulation in semi-arid regions, a spatially varying storage capacity (VSC) model was developed based on the spatial distribution of water storage capacity and the vertical hybrid runoff mechanism. To verify the applicability of the VSC model, both the VSC model and a hybrid runoff model were used to simulate daily runoff processes in the catchment upstream of the Dianzi hydrological station from 1973 to 1979. The results showed that the annual average Nash-Sutcliffe coefficient was 0.80 for the VSC model, and only 0.67 for the hybrid runoff model. The higher annual average Nash-Sutcliffe coefficient of the VSC model means that this hydrological model can better simulate daily runoff processes in semi-arid regions. Furthermore, as a distributed hydrological model, the VSC model can be applied in regional water resource management.

  8. Application of spatially varying storage capacity model for runoff parameterization in semi-arid catchment

    Directory of Open Access Journals (Sweden)

    Li-liang REN

    2009-06-01

    Full Text Available This paper introduces the method of designation of water storage capacity for each grid cell within a catchment, which considers topography, vegetation and soil synthetically. For the purpose of hydrological process simulation in semi-arid regions, a spatially varying storage capacity (VSC model was developed based on the spatial distribution of water storage capacity and the vertical hybrid runoff mechanism. To verify the applicability of the VSC model, both the VSC model and a hybrid runoff model were used to simulate daily runoff processes in the catchment upstream of the Dianzi hydrological station from 1973 to 1979. The results showed that the annual average Nash-Sutcliffe coefficient was 0.80 for the VSC model, and only 0.67 for the hybrid runoff model. The higher annual average Nash-Sutcliffe coefficient of the VSC model means that this hydrological model can better simulate daily runoff processes in semi-arid regions. Furthermore, as a distributed hydrological model, the VSC model can be applied in regional water resource management.

  9. Estimation of storage time of yogurt with artificial neural network modeling.

    Science.gov (United States)

    Sofu, A; Ekinci, F Y

    2007-07-01

    Changes in the physical, chemical, and microbiological structure of yogurt determine the storage and shelf life of the product. In this study, microbial counts and pH values of yogurt during storage were determined at d 1, 7, and 14. Simultaneously, image processing of yogurt was digitized by using a machine vision system (MVS) to determine color changes during storage, and the obtained data were modeled with an artificial neural network (ANN) for prediction of shelf life of set-type whole-fat and low-fat yogurts. The ANN models were developed using back-propagation networks with a single hidden layer and sigmoid activation functions. The input variables of the network were pH; total aerobic, yeast, mold, and coliform counts; and color analysis values measured by the machine vision system. The output variable was the storage time of the yogurt. The modeling results showed that there was excellent agreement between the experimental data and predicted values, with a high determination coefficient (R2 = 0.9996) showing that the developed model was able to analyze nonlinear multivariant data with very good performance, fewer parameters, and shorter calculation time. The model might be an alternative method to control the expiration date of yogurt shown in labeling and provide consumers with a safer food supply.

  10. Dynamic modeling of hybrid energy storage systems coupled to photovoltaic generation in residential applications

    Science.gov (United States)

    Maclay, James D.; Brouwer, Jacob; Samuelsen, G. Scott

    A model of a photovoltaic (PV) powered residence in stand-alone configuration was developed and evaluated. The model assesses the sizing, capital costs, control strategies, and efficiencies of reversible fuel cells (RFC), batteries, and ultra-capacitors (UC) both individually, and in combination, as hybrid energy storage devices. The choice of control strategy for a hybrid energy storage system is found to have a significant impact on system efficiency, hydrogen production and component utilization. A hybrid energy storage system comprised of batteries and RFC has the advantage of reduced cost (compared to using a RFC as the sole energy storage device), high system efficiency and hydrogen energy production capacity. A control strategy that preferentially used the RFC before the battery in meeting load demand allows both grid independent operation and better RFC utilization compared to a system that preferentially used the battery before the RFC. Ultra-capacitors coupled with a RFC in a hybrid energy storage system contain insufficient energy density to meet dynamic power demands typical of residential applications.

  11. Design and modelling of an innovative three-stage thermal storage system for direct steam generation CSP plants

    Science.gov (United States)

    Garcia, Pierre; Vuillerme, Valéry; Olcese, Marco; El Mourchid, Nadim

    2016-05-01

    Thermal Energy Storage systems (TES) for a Direct Steam Generation (DSG) solar plant feature preferably three stages in series including a latent heat storage module so that steam can be recovered with a limited temperature loss. The storage system designed within the Alsolen Sup project is characterized by an innovative combination of sensible and latent modules. A dynamic model of this three-stage storage has been developed and applied to size the storage system of the Alsolen Sup® plant demonstrator at CEA Cadarache. Results of this simulation show that this promising concept is an efficient way to store heat in DSG solar plants.

  12. Influence of Li-ion Battery Models in the Sizing of Hybrid Storage Systems with Supercapacitors

    OpenAIRE

    Pinto, Claudio; Barreras, Jorge Varela; Castro, Ricardo; Schaltz, Erik; Andreasen, Søren Juhl; Araujo, Rui Esteves

    2014-01-01

    This paper presents a comparative study of the influence of different aggregated electrical circuit battery models in the sizing process of a hybrid energy storage system (ESS), composed by Li-ion batteries and supercapacitors (SCs). The aim is to find the number of cells required to propel a certain vehicle over a predefined driving cycle. During this process, three battery models will be considered. The first consists in a linear static zeroeth order battery model over a restricted operatin...

  13. Thermal Storage Power Balancing with Model Predictive Control

    DEFF Research Database (Denmark)

    Halvgaard, Rasmus; Poulsen, Niels Kjølstad; Madsen, Henrik

    2013-01-01

    The method described in this paper balances power production and consumption with a large number of thermal loads. Linear controllers are used for the loads to track a temperature set point, while Model Predictive Control (MPC) and model estimation of the load behavior are used for coordination....... The total power consumption of all loads is controlled indirectly through a real-time price. The MPC incorporates forecasts of the power production and disturbances that influence the loads, e.g. time-varying weather forecasts, in order to react ahead of time. A simulation scenario demonstrates...

  14. NOX2-dependent regulation of inflammation.

    Science.gov (United States)

    Singel, Kelly L; Segal, Brahm H

    2016-04-01

    NADPH oxidase (NOX) isoforms together have multiple functions that are important for normal physiology and have been implicated in the pathogenesis of a broad range of diseases, including atherosclerosis, cancer and neurodegenerative diseases. The phagocyte NADPH oxidase (NOX2) is critical for antimicrobial host defence. Chronic granulomatous disease (CGD) is an inherited disorder of NOX2 characterized by severe life-threatening bacterial and fungal infections and by excessive inflammation, including Crohn's-like inflammatory bowel disease (IBD). NOX2 defends against microbes through the direct antimicrobial activity of reactive oxidants and through activation of granular proteases and generation of neutrophil extracellular traps (NETs). NETosis involves the breakdown of cell membranes and extracellular release of chromatin and neutrophil granular constituents that target extracellular pathogens. Although the immediate effects of oxidant generation and NETosis are predicted to be injurious, NOX2, in several contexts, limits inflammation and injury by modulation of key signalling pathways that affect neutrophil accumulation and clearance. NOX2 also plays a role in antigen presentation and regulation of adaptive immunity. Specific NOX2-activated pathways such as nuclear factor erythroid 2-related factor 2 (Nrf2), a transcriptional factor that induces antioxidative and cytoprotective responses, may be important therapeutic targets for CGD and, more broadly, diseases associated with excessive inflammation and injury.

  15. NOx Emissions from a Rotating Detonation-wave Engine

    Science.gov (United States)

    Kailasanath, Kazhikathra; Schwer, Douglas

    2016-11-01

    Rotating detonation-wave engines (RDE) are a form of continuous detonation-wave engines. They potentially provide further gains in performance than an intermittent or pulsed detonation-wave engine (PDE). The overall flow field in an idealized RDE, primarily consisting of two concentric cylinders, has been discussed in previous meetings. Because of the high pressures involved and the lack of adequate reaction mechanisms for this regime, previous simulations have typically used simplified chemistry models. However, understanding the exhaust species concentrations in propulsion devices is important for both performance considerations as well as estimating pollutant emissions. Progress towards addressing this need will be discussed in this talk. In this approach, an induction parameter model is used for simulating the detonation but a more detailed finite-chemistry model including NOx chemistry is used in the expansion flow region, where the pressures are lower and the uncertainties in the chemistry model are greatly reduced. Results show that overall radical concentrations in the exhaust flow are substantially lower than from earlier predictions with simplified models. Results to date show that NOx emissions are not a problem for the RDE due to the short residence times and the nature of the flow field. Furthermore, simulations show that the amount of NOx can be further reduced by tailoring the fluid dynamics within the RDE.

  16. Cryptography in the Bounded Quantum-Storage Model

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Serge, Fehr; Schaffner, Christian;

    2008-01-01

    We initiate the study of two-party cryptographic primitives with unconditional security, assuming that the adversary's quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory...

  17. Cryptography In The Bounded Quantum-Storage Model

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Salvail, Louis; Schaffner, Christian;

    2005-01-01

    We initiate the study of two-party cryptographic primitives with unconditional security, assuming that the adversary's quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory...

  18. Modeling and optimization of energy storage system for microgrid

    Science.gov (United States)

    Qiu, Xin

    The vanadium redox flow battery (VRB) is well suited for the applications of microgrid and renewable energy. This thesis will have a practical analysis of the battery itself and its application in microgrid systems. The first paper analyzes the VRB use in a microgrid system. The first part of the paper develops a reduced order circuit model of the VRB and analyzes its experimental performance efficiency during deployment. The statistical methods and neural network approximation are used to estimate the system parameters. The second part of the paper addresses the implementation issues of the VRB application in a photovoltaic-based microgrid system. A new dc-dc converter was proposed to provide improved charging performance. The paper was published on IEEE Transactions on Smart Grid, Vol. 5, No. 4, July 2014. The second paper studies VRB use within a microgrid system from a practical perspective. A reduced order circuit model of the VRB is introduced that includes the losses from the balance of plant including system and environmental controls. The proposed model includes the circulation pumps and the HVAC system that regulates the environment of the VRB enclosure. In this paper, the VRB model is extended to include the ESS environmental controls to provide a model that provides a more realistic efficiency profile. The paper was submitted to IEEE Transactions on Sustainable Energy. Third paper discussed the optimal control strategy when VRB works with other type of battery in a microgird system. The work in first paper is extended. A high level control strategy is developed to coordinate a lead acid battery and a VRB with reinforcement learning. The paper is to be submitted to IEEE Transactions on Smart Grid.

  19. Predictive model to describe water migration in cellular solid foods during storage

    NARCIS (Netherlands)

    Voogt, J.A.; Hirte, A.; Meinders, M.B.J.

    2011-01-01

    BACKGROUND: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. RESULTS: Water migration in cellular solid foods

  20. Water harvest- and storage- location assessment model using GIS and remote sensing

    Directory of Open Access Journals (Sweden)

    H. Weerasinghe

    2011-04-01

    Full Text Available This study describes a globally applicable method to determine the local suitability to implement water supply management strategies within the context of a river catchment. We apply this method, and develop a spatial analysis model named Geographic Water Management Potential (GWAMP. We retrieve input data from global data repositories and rescale these data to 1km spatial resolution to obtain a set of manageable input data. Potential runoff is calculated as an intermediate input using the Soil Conservation Service Curve Number (SCS-CN equation. Multi Criteria Evaluation techniques are used to determine the suitability levels and relative importance of input parameters for water supply management. Accordingly, the model identifies, potential water harvesting- and storage sites for on-farm water storage, regional dams, and soil moisture conservation.

    We apply the model to two case-study locations, the Sao-Francisco and Nile catchments, which differ in their geographic and climatic conditions. The model results are validated against existing data on hydrologic networks, reservoir capacities and runoff. On average, GWAMP predictions of sites with high rain water storage suitability correlate well (83% with the locations of existing regional dams and farm tanks. According to the results from testing and validation of the GWAMP we point out that the GWAMP can be used identify potential sites for rain water harvesting and storage technologies in a given catchment.

  1. Predictive model to describe water migration in cellular solid foods during storage

    NARCIS (Netherlands)

    Voogt, J.A.; Hirte, A.; Meinders, M.B.J.

    2011-01-01

    Background: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. Results: Water migration in cellular solid foods invo

  2. Modeling the effect of water activity and storage temperature on chemical stability of coffee brews.

    Science.gov (United States)

    Manzocco, Lara; Nicoli, Maria Cristina

    2007-08-08

    This work was addressed to study the chemical stability of coffee brew derivatives as a function of water activity (aw) and storage temperature. To this purpose, coffee brew was freeze-dried, equilibrated at increasing aw values, and stored for up to 10 months at different temperatures from -30 to 60 degrees C. The chemical stability of the samples was assessed by measuring H3O+ formation during storage. Independently of storage temperature, the rate of H3O+ formation was considerably low only when aw was reduced below 0.5 (94% w/w). Beyond this critical boundary, the rate increased, reaching a maximum value at ca. 0.8 aw (78% w/w). Further hydration up to the aw of the freshly prepared beverage significantly increased chemical stability. It was suggested that mechanisms other than lactones' hydrolysis, probably related to nonenzymatic browning pathways, could contribute to the observed increase in acidity during coffee staling. The temperature dependence of H3O+ formation was well-described by the Arrhenius equation in the entire aw range considered. However, aw affected the apparent activation energy and frequency factor. These effects were described by simple equations that were used to set up a modified Arrhenius equation. This model was validated by comparing experimental values, not used to generate the model, with those estimated by the model itself. The model allowed efficient prediction of the chemical stability of coffee derivatives on the basis of only the aw value and storage temperature.

  3. Predictive model to describe water migration in cellular solid foods during storage

    NARCIS (Netherlands)

    Voogt, J.A.; Hirte, A.; Meinders, M.B.J.

    2011-01-01

    BACKGROUND: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. RESULTS: Water migration in cellular solid foods invo

  4. Modeling, Analysis, and Design Insights for Shuttle-based Compact Storage Systems

    NARCIS (Netherlands)

    E. Tappia (Elena); D. Roy (Debjit); M.B.M. de Koster (René); M. Melacini (Marco)

    2015-01-01

    textabstractShuttle-based compact systems are new automated multi-deep unit-load storage systems with lifts that promise both low operational cost and large volume flexibility. In this paper, we develop novel queuing network models to estimate the performance of both single-tier and multi-tier shutt

  5. Storage binnen OAIS: Normatief Model en GAP Analysis voor Beeld en Geluid

    NARCIS (Netherlands)

    D. Steinmeier (Daniel)

    2013-01-01

    textabstractOne of the organisational goals of the Netherlands institute of Sound and Vision is to become an OAIS-compliant trustworthy digital archive. This document focuses on the Storage-functions within the OAIS-model and what measures and strategies need to be in place in order to fulfill the g

  6. General regression neural network model for behavior of Salmonella on chicken meat during cold storage

    Science.gov (United States)

    The objective of this study was to investigate and model the behavior of Salmonella on different types of chicken meat during frozen and refrigerated storage. Portions (0.69 to 0.83 g) of chicken meat (breast, skin, or thigh) were inoculated with a single strain (ATCC 700408) of Salmonella Typhimur...

  7. A Distributed Model Predictive Control approach for the integration of flexible loads, storage and renewables

    DEFF Research Database (Denmark)

    Ferrarini, Luca; Mantovani, Giancarlo; Costanzo, Giuseppe Tommaso

    2014-01-01

    This paper presents an innovative solution based on distributed model predictive controllers to integrate the control and management of energy consumption, energy storage, PV and wind generation at customer side. The overall goal is to enable an advanced prosumer to autoproduce part of the energy...... he needs with renewable sources and, at the same time, to optimally exploit the thermal and electrical storages, to trade off its comfort requirements with different pricing schemes (including real-time pricing), and apply optimal control techniques rather than sub-optimal heuristics....

  8. Model study of the thermal storage system by FEHM code

    Energy Technology Data Exchange (ETDEWEB)

    Tenma, N.; Yasukawa, Kasumi [National Institute of Advanced Industrial Science and Technology, Ibaraki (Japan); Zyvoloski, G. [Los Alamos National Laboratory, Los Alamos, NM (United States). Earth and Environmental Science Division

    2003-12-01

    The use of low-temperature geothermal resources is important from the viewpoint of global warming. In order to evaluate various underground projects that use low-temperature geothermal resources, we have estimated the parameters of a typical underground system using the two-well model. By changing the parameters of the system, six different heat extraction scenarios have been studied. One of these six scenarios is recommended because of its small energy loss. (author)

  9. Coupled process modelling with applications to radionuclide storage and disposal

    OpenAIRE

    English, Myles

    2013-01-01

    Radioactive waste repositories, designed in accordance with the current UK concept, would be required to provide containment for thousands of years beneath hundreds of metres of rock. The physical processes, both geological and other processes, that might lead to migration of radionuclides are slow in comparison to human timescales — it is impractical to make an experiment of the whole system and so these systems are typically investigated through the use of numerical models. P...

  10. Summertime NOx measurements during the CHABLIS campaign: can source and sink estimates unravel observed diurnal cycles?

    Directory of Open Access Journals (Sweden)

    H. K. Roscoe

    2009-09-01

    Full Text Available NOx measurements were conducted at the Halley Research Station, Antarctica, during the austral summer period 1 January–10 February 2005. A clear NOx diurnal cycle was observed with minimum concentrations close to instrumental detection limit (5 pptv measured between 04:00–05:00 GMT. NOx concentrations peaked (24 pptv between 19:00–20:00 GMT, approximately 5 h after local solar noon. An optimised box model of NOx concentrations based on production from in-snow nitrate photolysis and chemical loss derives a mean noon emission rate of 3.48×108 molecules cm−2 s−1, assuming a 100 m boundary layer mixing height, and a relatively short NOx lifetime of ~6.4 h. This emission rate compares to directly measured values ranging from 1.7 to 3.4×108 molecules cm−2 s−1 made on 3 days at the end of the study period. Calculations of the maximum rate of NO2 loss via a variety of conventional HOx and halogen oxidation processes show that the lifetime of NOx is predominantly controlled by halogen processing, namely BrNO3 and INO3 gas-phase formation and their subsequent heterogeneous uptake, with a potential smaller contribution from HNO4 formation and uptake. Furthermore the presence of halogen oxides is shown to significantly perturb NOx concentrations by decreasing the NO/NO2 ratio. We conclude that in coastal Antarctica, the potential ozone production efficiency of NOx emitted from the snowpack is mitigated by the more rapid NOx loss due to halogen nitrate hydrolysis. These results suggest that the role of halogen oxides need to be considered when interpreting the isotopic signature of nitrate impurities held within snow and ice.

  11. Modeling and Analysis of the Role of Fast-Response Energy Storage in the Smart Grid

    CERN Document Server

    Su, Han-I

    2011-01-01

    The large short time-scale variability of renewable energy resources presents significant challenges to the reliable operation of power systems. This variability can be mitigated by deploying fast-ramping generators. However, these generators are costly to operate and produce environmentally harmful emissions. Fast-response energy storage devices, such as batteries and flywheels, provide an environmentally friendly alternative, but are expensive and have limited capacity. To study the environmental benefits of storage, we introduce a slotted-time dynamic residual dc power flow model with the prediction error of the difference between the generation (including renewables) and the load as input and the fast-ramping generation and the storage (charging/discharging) operation as the control variables used to ensure that the demand is satisfied (as much as possible) in each time slot. We assume the input prediction error sequence to be i.i.d. zero-mean random variables. The optimal power flow problem is then formu...

  12. Pumped storage system model and experimental investigations on S-induced issues during transients

    Science.gov (United States)

    Zeng, Wei; Yang, Jiandong; Hu, Jinhong

    2017-06-01

    Because of the important role of pumped storage stations in the peak regulation and frequency control of a power grid, pump turbines must rapidly switch between different operating modes, such as fast startup and load rejection. However, pump turbines go through the unstable S region in these transition processes, threatening the security and stability of the pumped storage station. This issue has mainly been investigated through numerical simulations, while field experiments generally involve high risks and are difficult to perform. Therefore, in this work, the model test method was employed to study S-induced security and stability issues for a pumped storage station in transition processes. First, a pumped storage system model was set up, including the piping system, model units, electrical control systems and measurement system. In this model, two pump turbines with different S-shaped characteristics were installed to determine the influence of S-shaped characteristics on transition processes. The model platform can be applied to simulate any hydraulic transition process that occurs in real power stations, such as load rejection, startup, and grid connection. On the experimental platform, the S-shaped characteristic curves were measured to be the basis of other experiments. Runaway experiments were performed to verify the impact of the S-shaped characteristics on the pump turbine runaway stability. Full load rejection tests were performed to validate the effect of the S-shaped characteristics on the water-hammer pressure. The condition of one pump turbine rejecting its load after another defined as one-after-another (OAA) load rejection was performed to validate the possibility of S-induced extreme draft tube pressure. Load rejection experiments with different guide vane closing schemes were performed to determine a suitable scheme to adapt the S-shaped characteristics. Through these experiments, the threats existing in the station were verified, the

  13. A New Approach for NOx Soft Sensors for the Aftertreatment of Diesel Engines

    Science.gov (United States)

    Ishizuka, S.; Kajiwara, I.; Sato, J.; Hanamura, Y.

    2016-09-01

    To maintain the NOX concentration at an appropriate level, traditionally an air-path control that regulates the intake and exhaust system of diesel engines aims to control the mass air flow and the manifold absolute pressure, which influence the production of NOX. To improve the control accuracy, a more recent approach takes the NOX concentration directly as a controlled output variable, but the sensors monitoring the NOX concentration are slow to respond. Consequently, a direct sensor is inappropriate as a feedback controller. Instead a mechanism called a soft sensor, which computes the NOX concentration from state quantities of diesel engines, is used. Because the prediction accuracy from the sensor model greatly affects the control performance, it is important to improve the model accuracy. However, deviations in the steady state indicate an insufficient model accuracy. This study proposes a method to construct an adaptive NOX soft sensor that corrects the parameters of the sensor model sequentially using the simultaneous perturbation stochastic approximation while comparing the values computed by the software to actual measurements as well as examines the effectiveness of the proposed method experimentally.

  14. Lactose/beta-lactoglobulin interaction during storage of model whey powders.

    Science.gov (United States)

    Thomas, M E C; Scher, J; Desobry, S

    2004-05-01

    The objective of this study was to evaluate the presence or absence of interaction between lactose and beta-lactoglobulin during storage of model whey powders at different water activities (a(w)). Model whey powders were prepared by colyophilization of lactose with increasing quantities of beta-lactoglobulin. These colyophilized beta-lactoglobulin:lactose powders, assigned as BL powders, were stored from 0.11 to 0.95 a(w). The water sorption behavior of BL powders was studied gravimetrically, and the state of lactose was investigated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Before storage, BL powders were amorphous. After storage, a loss of water was observed on moisture sorption isotherms of BL powders. It was related to the formation of lactose crystals, detected by DSC and SEM analysis, and to the structural collapse of the powders. Water loss due to lactose crystallization was shifted to higher a(w) with increasing beta-lactoglobulin content in BL powders. Moreover, kinetics of moisture sorption demonstrated that beta-lactoglobulin was also responsible for a slower crystallization process in BL powders. Then, the water sorption behavior of BL powders was very different from the behavior of the 2 compounds mixed after separate lyophilization. All these results pointed out interaction between lactose and beta-lactoglobulin, which appeared during lyophilization and still occurred during storage. This lactose/beta-lactoglobulin interaction stabilized model whey powders against lactose crystallization.

  15. Implementation for Model of Adsoptive Hydrogen Storage Using UDF in Fluent

    Science.gov (United States)

    Ye, Feng; Xiao, Jinsheng; Hu, Binxiang; Benard, Pierre; Chahine, Richard

    This paper builds an axisymmetrical geometry model and simulates the charging, domancy, discharging and domancy processes of hydrogen storage tank based on activated carbon bed in a steel container at room temperature (302K) and medium storage pressure (10 MPa). The CFD model is based on the mass, momentum and energy conservation equations of the hydrogen storage system formed of gaseous and adsorbed hydrogen, activated carbon bed and steel tank wall. The adsorption model is based on Dubinin-Astakov adsorption isotherms. The simulation is implemented using a finite volume method through the computational fluid dynamics commercial software Fluent. User defined functions (UDFs) hooked in Fluent software are given to set the boundary conditions or modify the mass and energy conservation equations.The simulating results have good agreement with experimental results. Results show that the temperature of central region is higher than that near the wall during the charging process,while the temperature of central region is lower than that near the wall during the discharging process.The amount of adsorbed hydrogen is greater than that of the compressed gaseous hydrogen. Hydrogen storage by adsorption on high surface area activated carbon has obvious advantages.

  16. Experimental testing procedures and dynamic model validation for vanadium redox flow battery storage system

    Science.gov (United States)

    Baccino, Francesco; Marinelli, Mattia; Nørgård, Per; Silvestro, Federico

    2014-05-01

    The paper aims at characterizing the electrochemical and thermal parameters of a 15 kW/320 kWh vanadium redox flow battery (VRB) installed in the SYSLAB test facility of the DTU Risø Campus and experimentally validating the proposed dynamic model realized in Matlab-Simulink. The adopted testing procedure consists of analyzing the voltage and current values during a power reference step-response and evaluating the relevant electrochemical parameters such as the internal resistance. The results of different tests are presented and used to define the electrical characteristics and the overall efficiency of the battery system. The test procedure has general validity and could also be used for other storage technologies. The storage model proposed and described is suitable for electrical studies and can represent a general model in terms of validity. Finally, the model simulation outputs are compared with experimental measurements during a discharge-charge sequence.

  17. Effective NOx remediation from a surrogate flue gas using the US NRL Electra electron beam facility

    Science.gov (United States)

    Petrova, Tz. B.; Petrov, G. M.; Wolford, M. F.; Giuliani, J. L.; Ladouceur, H. D.; Hegeler, F.; Myers, M. C.; Sethian, J. D.

    2017-02-01

    Nitric oxide (NOx) emission is under restrictive federal regulations because of its negative impact on atmosphere, biosphere, and human health. Therefore, its removal has been a subject of extensive research to develop new efficient and cost effective techniques that can be applied on an industrial scale. In this work, we study both experimentally and theoretically an effective removal of NOx pollutants from a surrogate flue gas (SFG) using high power electron beam (e-beam) pulses. SFG is a simulant for exhaust from coal combustion power plants (82% N2, 6% O2, 12% CO2, and ˜100 ppm of NOx). The pulsed electron beam is generated using the United States Naval Research Laboratory Electra facility, which delivers e-beams with energies of ˜500 keV and a power pulse duration of ˜140 ns. During the e-beam irradiation, the energetic electrons generate a non-equilibrium plasma containing chemically active species, which then react with NOx to form harmless substances. A non-equilibrium time-dependent model is developed to describe NOx remediation from SFG. The model combines e-beam deposition rates obtained by solving the electron Boltzmann equation and extensive plasma chemistry modeling, which follows the species on a time scale from sub-nanoseconds to a few seconds. NOx decomposition as a function of electron beam parameters is studied. It is demonstrated experimentally that short (ns) pulses are the most efficient for NOx removal. A sharp reduction of NOx was measured with e-beam power deposition increasing, following the trend predicted by the model, achieving a 20 fold reduction to ˜5 ppm at energy deposition ˜20 J/l.

  18. Modeling, Design and Simulation of Stand-Alone Photovoltaic Power Systems with Battery Storage

    OpenAIRE

    Abd Essalam BADOUD; Mabrouk KHEMLICHE

    2013-01-01

    Stand alone renewable energy based on photovoltaic systems accompanied with battery storage system are beginning to play an important role over the world to supply power to remote areas. The objective of the study reported in this paper is to elaborate and design a bond graphs model for sizing stand-alone domestic solar photovoltaic electricity systems and simulating the performance of the systems in a tropical climate. The systems modelled consist of an array of PV modules, a lead-acid batte...

  19. Subgrid Parameterization of the Soil Moisture Storage Capacity for a Distributed Rainfall-Runoff Model

    Directory of Open Access Journals (Sweden)

    Weijian Guo

    2015-05-01

    Full Text Available Spatial variability plays an important role in nonlinear hydrologic processes. Due to the limitation of computational efficiency and data resolution, subgrid variability is usually assumed to be uniform for most grid-based rainfall-runoff models, which leads to the scale-dependence of model performances. In this paper, the scale effect on the Grid-Xinanjiang model was examined. The bias of the estimation of precipitation, runoff, evapotranspiration and soil moisture at the different grid scales, along with the scale-dependence of the effective parameters, highlights the importance of well representing the subgrid variability. This paper presents a subgrid parameterization method to incorporate the subgrid variability of the soil storage capacity, which is a key variable that controls runoff generation and partitioning in the Grid-Xinanjiang model. In light of the similar spatial pattern and physical basis, the soil storage capacity is correlated with the topographic index, whose spatial distribution can more readily be measured. A beta distribution is introduced to represent the spatial distribution of the soil storage capacity within the grid. The results derived from the Yanduhe Basin show that the proposed subgrid parameterization method can effectively correct the watershed soil storage capacity curve. Compared to the original Grid-Xinanjiang model, the model performances are quite consistent at the different grid scales when the subgrid variability is incorporated. This subgrid parameterization method reduces the recalibration necessity when the Digital Elevation Model (DEM resolution is changed. Moreover, it improves the potential for the application of the distributed model in the ungauged basin.

  20. Second Approximation Model for Optical Head in Super High Density Storage Technology

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The paper presents second approximation model for optical head in super high-density storage technology firstly and it is an important part for three grades approximate model of ultra-small-size quantum well corn-shaped laser and simulative calculations. It supplies the important and useful results for the NFOD optical head design with ultra thin active layer and ultra small spot laser.

  1. Food Prices and Climate Extremes: A Model of Global Grain Price Variability with Storage

    Science.gov (United States)

    Otto, C.; Schewe, J.; Frieler, K.

    2015-12-01

    Extreme climate events such as droughts, floods, or heat waves affect agricultural production in major cropping regions and therefore impact the world market prices of staple crops. In the last decade, crop prices exhibited two very prominent price peaks in 2007-2008 and 2010-2011, threatening food security especially for poorer countries that are net importers of grain. There is evidence that these spikes in grain prices were at least partly triggered by actual supply shortages and the expectation of bad harvests. However, the response of the market to supply shocks is nonlinear and depends on complex and interlinked processes such as warehousing, speculation, and trade policies. Quantifying the contributions of such different factors to short-term price variability remains difficult, not least because many existing models ignore the role of storage which becomes important on short timescales. This in turn impedes the assessment of future climate change impacts on food prices. Here, we present a simple model of annual world grain prices that integrates grain stocks into the supply and demand functions. This firstly allows us to model explicitly the effect of storage strategies on world market price, and thus, for the first time, to quantify the potential contribution of trade policies to price variability in a simple global framework. Driven only by reported production and by long--term demand trends of the past ca. 40 years, the model reproduces observed variations in both the global storage volume and price of wheat. We demonstrate how recent price peaks can be reproduced by accounting for documented changes in storage strategies and trade policies, contrasting and complementing previous explanations based on different mechanisms such as speculation. Secondly, we show how the integration of storage allows long-term projections of grain price variability under climate change, based on existing crop yield scenarios.

  2. Rise and fall of the NOx emissions trade; Opkomst en ondergang van NOx-emissiehandel

    Energy Technology Data Exchange (ETDEWEB)

    Van der Velde, R. [Royal Haskoning DHV, Amersfoort (Netherlands); Van der Kolk, J. [Van der Kolk Advies, Soest (Netherlands)

    2013-04-15

    In 2005, the Netherlands started NOx emission trading. In 2014 they are terminating these activities. Are they stopping because the targets have been realized? This article provides an overview of the developments and experiences that have ultimately led to the termination of the NOx emission trade in the Netherlands [Dutch] In 2005 is Nederland begonnen in NOx-emissiehandel. In 2014 stoppen we er weer mee. Stoppen we omdat de doelen zijn gehaald? Een overzicht wordt gegeven van de ontwikkelingen en ervaringen die uiteindelijk hebben geleid tot beeindiging van de NOx-emissiehandel in Nederland.

  3. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    S. Wu

    2003-12-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the October 1 to December 31, 2003 time period.

  4. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    S. Wu; Z. Fan; R. Herman

    2004-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the January 1 to March 31, 2004 time period.

  5. Congressionally Directed Project for Passive NOx Removal Catalysts Research

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, William [Univ. of Notre Dame, IN (United States)

    2014-12-29

    The Recipient proposes to produce new scientific and technical knowledge and tools to enable the discovery and deployment of highly effective materials for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) from lean combustion exhaust. A second goal is to demonstrate a closely coupled experimental and computational approach to heterogeneous catalysis research. These goals will be met through the completion of four primary technical objectives: First, an in-depth kinetic analysis will be performed on two prominent classes of NOx SCR catalysts, Fe- and Cu-exchanged beta and ZSM-5 zeolites, over a wide range of catalyst formulation and under identical, high conversion conditions as a function of gas phase composition. Second, the nanoscale structure and adsorption chemistry of these high temperature (HT) and low temperature (LT) catalysts will be determined using in situ and operando spectroscopy under the same reaction conditions. Third, first-principles molecular simulations will be used to model the metal-zeolite active sites, their adsorption chemistry, and key steps in catalytic function. Fourth, this information will be integrated into chemically detailed mechanistic and kinetic descriptions and models of the operation of these well- defined NOx SCR catalysts under practically relevant reaction conditions. The new knowledge and models that derive from this work will be published in the scientific literature.

  6. Congressionally Directed Project for Passive NOx Removal Catalysts Research

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, William

    2014-08-29

    The Recipient proposes to produce new scientific and technical knowledge and tools to enable the discovery and deployment of highly effective materials for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) from lean combustion exhaust. A second goal is to demonstrate a closely coupled experimental and computational approach to heterogeneous catalysis research. These goals will be met through the completion of four primary technical objectives: First, an in-depth kinetic analysis will be performed on two prominent classes of NOx SCR catalysts, Fe- and Cu-exchanged beta and ZSM-5 zeolites, over a wide range of catalyst formulation and under identical, high conversion conditions as a function of gas phase composition. Second, the nanoscale structure and adsorption chemistry of these high temperature (HT) and low temperature (LT) catalysts will be determined using in situ and operando spectroscopy under the same reaction conditions. Third, first-principles molecular simulations will be used to model the metal-zeolite active sites, their adsorption chemistry, and key steps in catalytic function. Fourth, this information will be integrated into chemically detailed mechanistic and kinetic descriptions and models of the operation of these well- defined NOx SCR catalysts under practically relevant reaction conditions. The new knowledge and models that derive from this work will be published in the scientific literature.

  7. A dynamic programming model for optimal planning of aquifer storage and recovery facility operations

    Science.gov (United States)

    Uddameri, V.

    2007-01-01

    Aquifer storage recovery (ASR) is an innovative technology with the potential to augment dwindling water resources in regions experiencing rapid growth and development. Planning and design of ASR systems requires quantifying how much water should be stored and appropriate times for storage and withdrawals within a planning period. A monthly scale planning model has been developed in this study to derive optimal (least cost) long-term policies for operating ASR systems and is solved using a recursive deterministic dynamic programming approach. The outputs of the model include annual costs of operation, the amount of water to be imported each month as well as the schedule for storage and extraction. A case study modeled after a proposed ASR system for Mustang Island and Padre Island service areas of the city of Corpus Christi is used to illustrate the utility of the developed model. The results indicate that for the assumed baseline demands, the ASR system is to be kept operational for a period of 4 months starting from May through August. Model sensitivity analysis indicated that increased seasonal shortages can be met using ASR with little additional costs. For the assumed cost structure, a 16% shortage increased the costs by 1.6%. However, the operation time of ASR increased from 4 to 8 months. The developed dynamic programming model is a useful tool to assess the feasibility of evaluating the use of ASR systems during regional-scale water resources planning endeavors.

  8. A Chance-Constrained Economic Dispatch Model in Wind-Thermal-Energy Storage System

    Directory of Open Access Journals (Sweden)

    Yanzhe Hu

    2017-03-01

    Full Text Available As a type of renewable energy, wind energy is integrated into the power system with more and more penetration levels. It is challenging for the power system operators (PSOs to cope with the uncertainty and variation of the wind power and its forecasts. A chance-constrained economic dispatch (ED model for the wind-thermal-energy storage system (WTESS is developed in this paper. An optimization model with the wind power and the energy storage system (ESS is first established with the consideration of both the economic benefits of the system and less wind curtailments. The original wind power generation is processed by the ESS to obtain the final wind power output generation (FWPG. A Gaussian mixture model (GMM distribution is adopted to characterize the probabilistic and cumulative distribution functions with an analytical expression. Then, a chance-constrained ED model integrated by the wind-energy storage system (W-ESS is developed by considering both the overestimation costs and the underestimation costs of the system and solved by the sequential linear programming method. Numerical simulation results using the wind power data in four wind farms are performed on the developed ED model with the IEEE 30-bus system. It is verified that the developed ED model is effective to integrate the uncertain and variable wind power. The GMM distribution could accurately fit the actual distribution of the final wind power output, and the ESS could help effectively decrease the operation costs.

  9. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Science.gov (United States)

    2010-07-01

    ... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection...

  10. Correlating Engine NOx Emission with Biodiesel Composition

    Science.gov (United States)

    Jeyaseelan, Thangaraja; Mehta, Pramod Shankar

    2016-06-01

    Biodiesel composition comprising of saturated and unsaturated fatty acid methyl esters has a significant influence on its properties and hence the engine performance and emission characteristics. This paper proposes a comprehensive approach for composition-property-NOx emission analysis for biodiesel fuels and highlights the pathways responsible for such a relationship. Finally, a procedure and a predictor equation are developed for the assessment of biodiesel NOx emission from its composition details.

  11. PHOTOCATALYTIC OXIDATION FOR NOx ABATEMENT: DEVELOPMENT OF A KINETIC EXPRESSION AND DESIGN TOOLS

    Energy Technology Data Exchange (ETDEWEB)

    Rajiv Srivastava; M. A. Ebadian

    2000-09-15

    The ''Nitrogen Oxides Emission Reduction Program'' and ''Ozone Non-Attainment Program'' in the 1990 Clean Air Act provide guidelines for controlling NOx (NO and NO{sub 2}) emissions in new and existing stationary sources. NOx emissions have local (air quality), regional (acid rain), and global (ozone production) consequences. This study aids in developing the photocatalyst technology that has potential for use in abatement of NOx. The objective of the proposed project is to apply the principles of chemical engineering fundamentals--reaction kinetics, transport phenomena and thermodynamics--in the process design for a system that will utilize a photocatalytic reactor to oxidize NOx to nitric acid (HNO{sub 3}). HNO{sub 3} can be more easily trapped than NOx on adsorbent surfaces or in water. The project dealt with the engineering aspect of the gas-solid heterogeneous oxidation of NOx. The experiments were conducted in a photocatalyst wash-coated glass flow tube reactor. A mathematical model was developed based on a rigorous description of the physical and chemical processes occurring in the reactor. The mathematical model took into account (1) intrinsic reaction kinetics (i.e., true reaction rates), (2) transport phenomena that deal with the mass transfer effects in the reactor, and (3) the geometry of the reactor. The experimental results were used for validation of the mathematical model that provides the basis for a versatile and reliable method for the purpose of design, scale-up and process control. The NOx abatement was successfully carried out in a flow tube reactor surrounded by black lights under the exploratory grant. Due to lack of funds, a comprehensive kinetic analysis for the photocatalytic reaction scheme could not be carried out. The initial experiments look very promising for use of photocatalysis for NOx abatement.

  12. A storage-based model of heterocyst commitment and patterning in cyanobacteria

    CERN Document Server

    Brown, Aidan I

    2013-01-01

    When deprived of fixed nitrogen (fN), certain filamentous cyanobacteria differentiate nitrogen-fixing heterocysts. There is a large and dynamic fraction of stored fN in cyanobacterial cells, but its role in directing heterocyst commitment has not been identified. We present an integrated computational model of fN transport, cellular growth, and heterocyst commitment for filamentous cyanobacteria. By including fN storage proportional to cell length, but without any explicit cell-cycle effect, we are able to recover a broad and late range of heterocyst commitment times and we observe a strong indirect cell-cycle effect. We propose that fN storage is an important component of heterocyst commitment and patterning in filamentous cyanobacteria. The model allows us to explore both initial and steady-state heterocyst patterns. The developmental model is hierarchical after initial commitment: our only source of stochasticity is observed growth rate variability. Explicit lateral inhibition allows us to examine $\\Delta$...

  13. Control of NOx during stationary combustion

    Energy Technology Data Exchange (ETDEWEB)

    James T. Yeh; Wei-Yin Chen

    2004-11-01

    Nitrogen oxides (NOx) and sulfur oxides (SOx) emissions are primary contributors to acid rain, which is associated with a number of effects including acidification of lakes and streams, accelerated corrosion of buildings, and visibility impairment. Among the various nitrogen oxides emitted from stationary combustion; nitrogen oxide (NO), nitrous oxide (N{sub 2}O), and nitrogen dioxide (NO{sub 2}) are stable, and NO predominates (over 90%). In health effects, NO{sub 2} can irritate the lungs and lower resistance to respiratory infection. In the area of ozone nonattainment, NOx and volatile organic compounds (VOCs) react in the atmosphere to form ozone, a photochemical oxidant and a major component of smog. Atmospheric ozone can cause respiratory problems by damaging lung tissue and reducing lung function. It is generally believed that over 80% of the total NOx emitted to the atmosphere originate at sources where fossil fuels and industrial wastes are burned. About one-half of the emissions are produced during combustion of fossil fuels in the utility industries. The rate of NOx formation is affected by fuel nitrogen content and by combustor design parameters. Higher firing temperature and combustor pressure increase NOx emissions. Nitric acid plants also produce large amounts of NOx as waste gas, but in much higher concentration than emissions from utility boiler flue gas.

  14. Observations of a seasonal cycle in NOx emissions from fires in the African savanna

    Science.gov (United States)

    Mebust, A. K.; Cohen, R. C.

    2012-12-01

    Nitrogen oxide (NOx) emissions from wildfires account for ~15% of the global total, inducing large fluctuations in the chemical production and loss rates of O3 and CH4 and thereby affecting Earth's radiative balance. NOx emissions from fires depend on fuel N content, combustion stage, and total biomass burned; sparse observations limit current understanding of the variability in these factors across biomes. Here we use satellite-based measurements to study emission coefficients (ECs), a value proportional to emission factors i.e. NOx emitted per unit of biomass burned, from fires in African savannas. NOx ECs decrease steadily across the fire season, rather than remaining constant as is currently assumed. We speculate that this is due to reallocation of nutrients, including N, to plant roots after the growing season. We account for the observed cycle in the GEOS-Chem chemical transport model to show the impacts on monthly tropospheric ozone.

  15. Model for energy conversion in renewable energy system with hydrogen storage

    Science.gov (United States)

    Kélouwani, S.; Agbossou, K.; Chahine, R.

    A dynamic model for a stand-alone renewable energy system with hydrogen storage (RESHS) is developed. In this system, surplus energy available from a photovoltaic array and a wind turbine generator is stored in the form of hydrogen, produced via an electrolyzer. When the energy production from the wind turbine and the photovoltaic array is not enough to meet the load demand, the stored hydrogen can then be converted by a fuel cell to produce electricity. In this system, batteries are used as energy buffers or for short time storage. To study the behavior of such a system, a complete model is developed by integrating individual sub-models of the fuel cell, the electrolyzer, the power conditioning units, the hydrogen storage system, and the batteries (used as an energy buffer). The sub-models are valid for transient and steady state analysis as a function of voltage, current, and temperature. A comparison between experimental measurements and simulation results is given. The model is useful for building effective algorithms for the management, control and optimization of stand-alone RESHSs.

  16. Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Saxon, Aron R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Keyser, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lundstrom, Blake R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-25

    Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System: Preprint Lithium-ion (Li-ion) batteries are being deployed on the electrical grid for a variety of purposes, such as to smooth fluctuations in solar renewable power generation. The lifetime of these batteries will vary depending on their thermal environment and how they are charged and discharged. To optimal utilization of a battery over its lifetime requires characterization of its performance degradation under different storage and cycling conditions. Aging tests were conducted on commercial graphite/nickel-manganese-cobalt (NMC) Li-ion cells. A general lifetime prognostic model framework is applied to model changes in capacity and resistance as the battery degrades. Across 9 aging test conditions from 0oC to 55oC, the model predicts capacity fade with 1.4 percent RMS error and resistance growth with 15 percent RMS error. The model, recast in state variable form with 8 states representing separate fade mechanisms, is used to extrapolate lifetime for example applications of the energy storage system integrated with renewable photovoltaic (PV) power generation.

  17. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    Directory of Open Access Journals (Sweden)

    P. Castellanos

    2013-08-01

    Full Text Available Biomass burning is an important contributor to global total emissions of NOx (NO + NO2. Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome specific emission factors, defined in units of grams of NO per kilogram of dry matter consumed. Emission factors are a significant source of uncertainty in bottom-up fire emissions modeling because relatively few observations are available to characterize the large spatial and temporal variability of burning conditions. In this paper we use NO2 tropospheric column observations from the Ozone Monitoring Instrument (OMI from the year 2005 over South America to calculate monthly NOx emission factors for four fire types: deforestation, savanna/grassland, woodland, and agricultural waste burning. In general, the spatial trends in NOx emission factors calculated in this work are consistent with emission factors derived from in situ measurements from the region, but are more variable than published biome specific global average emission factors widely used in bottom up fire emissions inventories such as the Global Fire Emissions Database (GFED v3. Satellite based NOx emission factors also indicate substantial temporal variability in burning conditions. Overall, we found that deforestation fires have the lowest NOx emission factors, on average 30 % lower than the emission factors used in GFED v3. Agricultural fire NOx emission factors were the highest, on average a factor of 2 higher than GFED v3 values. For savanna, woodland, and deforestation fires early dry season NOx emission factors were a factor of ~1.5–2.0 higher than late dry season emission factors. A minimum in the NOx emission factor seasonal cycle for deforestation fires occurred in August, the time period of severe drought in South America in 2005. Our results support the hypothesis that prolonged dry spells may lead to an increase in the contribution of smoldering combustion

  18. Pressure Effects on the Thermal De-NOx Process

    DEFF Research Database (Denmark)

    Kjærgaard, Karsten; Glarborg, Peter; Dam-Johansen, Kim

    1996-01-01

    The effect of pressure on the thermal de-NOx process has been investigated in flow reactor experiments. The experiments were performed at pressures from 1 to 10 bar and temperatures ranging from 925 to 1375 K. The inlet O-2 level was varied from 1000 ppm to 10%, while NH3 and NO were maintained...... at 1000 and 500 ppm, respectively At the highest pressure, CO was added to shift the regime for NO reduction to lower temperatures. The results show that the pressure affects the location and the width of the temperature window for NO reduction. As the pressure is increased, both the lower and the higher...... effect of the pressure but also cause a slight decrease in the NO reduction potential. The results are consistent with recent atmospheric pressure experiments of thermal de-NOx covering a wide range of reactant partial pressures. Comparisons of the experimental data with the recent chemical kinetic model...

  19. An overview of photocatalysis phenomena applied to NOx abatement.

    Science.gov (United States)

    Ângelo, Joana; Andrade, Luísa; Madeira, Luís M; Mendes, Adélio

    2013-11-15

    This review provides a short introduction to photocatalysis technology in terms of the present environmental remediation paradigm and, in particular, NOx photoabatement. The fundamentals of photoelectrochemical devices and the photocatalysis phenomena are reviewed, highlighting the main reaction mechanisms. The critical historical developments on heterogeneous photocatalysis are briefly discussed, giving particular emphasis to the pioneer works in this field. The third part of this work focus mainly on NOx removal technology considering topics such as: TiO2 photochemistry; effect of the operating conditions on the photocatalysis process; Langmuir-Hinshelwood modeling; TiO2 photocatalytic immobilization approaches; and their applications. The last section of the paper presents the main conclusions and perspectives on the opportunities related to this technology.

  20. Evapotranspiration from drained wetlands with different hydrologic regimes: Drivers, modeling, and storage functions

    Science.gov (United States)

    Wu, Chin-Lung; Shukla, Sanjay; Shrestha, Niroj K.

    2016-07-01

    We tested whether the current understanding of insignificant effect of drainage on evapotranspiration (ET) in the temperate region wetlands applies to those in the subtropics. Hydro-climatic drivers causing the changes in drained wetlands were identified and used to develop a generic model to predict wetland ET. Eddy covariance (EC)-based ET measurements were made for two years at two differently drained but close by wetlands, a heavily drained wetland (SW) (97% reduced surface storage) and a more functional wetland (DW) (42% reduced storage). Annual ET for more intensively drained SW was 836 mm, 34% less than DW (1271 mm) and the difference was significant (p = 0.001). This difference was mainly due to drainage driven differences in inundation and associated effects on net radiation (Rn) and local relative humidity. Two generic daily ET models, a regression model (MSE = 0.44 mm2, R2 = 0.80) and a machine learning-based Relevance Vector Machine (RVM) model (MSE = 0.36 mm2, R2 = 0.84), were developed with the latter being more robust. The RVM model can predict changes in ET for different restoration scenarios; a 1.1 m rise in drainage level showed 7% increase ET (18 mm) at SW while the increase at DW was negligible. The additional ET, 28% of surface flow, can enhance water storage, flood protection, and climate mitigation services at SW compared to DW. More intensely drained wetlands at higher elevation should be targeted for restoration for enhanced storage through increased ET. The models developed can predict changes in ET for improved evaluation of basin-scale effects of restoration programs and climate change scenarios.

  1. Transient Thermal Model and Analysis of the Lunar Surface and Regolith for Cryogenic Fluid Storage

    Science.gov (United States)

    Christie, Robert J.; Plachta, David W.; Yasan, Mohammad M.

    2008-01-01

    A transient thermal model of the lunar surface and regolith was developed along with analytical techniques which will be used to evaluate the storage of cryogenic fluids at equatorial and polar landing sites. The model can provide lunar surface and subsurface temperatures as a function of latitude and time throughout the lunar cycle and season. It also accounts for the presence of or lack of the undisturbed fluff layer on the lunar surface. The model was validated with Apollo 15 and Clementine data and shows good agreement with other analytical models.

  2. Dynamic Modeling of Adjustable-Speed Pumped Storage Hydropower Plant: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Singh, M.; Gevorgian, V.; Mohanpurkar, M.; Havsapian, R.; Koritarov, V.

    2015-04-06

    Hydropower is the largest producer of renewable energy in the U.S. More than 60% of the total renewable generation comes from hydropower. There is also approximately 22 GW of pumped storage hydropower (PSH). Conventional PSH uses a synchronous generator, and thus the rotational speed is constant at synchronous speed. This work details a hydrodynamic model and generator/power converter dynamic model. The optimization of the hydrodynamic model is executed by the hydro-turbine controller, and the electrical output real/reactive power is controlled by the power converter. All essential controllers to perform grid-interface functions and provide ancillary services are included in the model.

  3. Estimates of lightning NOx production from GOME satellite observations

    Directory of Open Access Journals (Sweden)

    K. F. Boersma

    2005-01-01

    Full Text Available Tropospheric NO2 column retrievals from the Global Ozone Monitoring Experiment (GOME satellite spectrometer are used to quantify the source strength and 3-D distribution of lightning produced nitrogen oxides (NOx=NO+NO2. A sharp increase of NO2 is observed at convective cloud tops with increasing cloud top height, consistent with a power-law behaviour with power 5±2. Convective production of clouds with the same cloud height are found to produce NO2 with a ratio 1.6/1 for continents compared to oceans. This relation between cloud properties and NO2 is used to construct a 10:30 local time global lightning NO2 production map for 1997. An extensive statistical comparison is conducted to investigate the capability of the TM3 chemistry transport model to reproduce observed patterns of lightning NO2 in time and space. This comparison uses the averaging kernel to relate modelled profiles of NO2 to observed NO2 columns. It exploits a masking scheme to minimise the interference of other NOx sources on the observed total columns. Simulations are performed with two lightning parameterizations, one relating convective preciptation (CP scheme to lightning flash distributions, and the other relating the fifth power of the cloud top height (H5 scheme to lightning distributions. The satellite-retrieved NO2 fields show significant correlations with the simulated lightning contribution to the NO2 concentrations for both parameterizations. Over tropical continents modelled lightning NO2 shows remarkable quantitative agreement with observations. Over the oceans however, the two model lightning parameterizations overestimate the retrieved NO2 attributed to lightning. Possible explanations for these overestimations are discussed. The ratio between satellite-retrieved NO2 and modelled lightning NO2 is used to rescale the original modelled lightning NOx production. Eight estimates of the lightning NOx production in 1997 are obtained from spatial and temporal

  4. Estimates of lightning NOx production from GOME satellite observations

    Directory of Open Access Journals (Sweden)

    H. M. Kelder

    2005-05-01

    Full Text Available Tropospheric NO2 column retrievals from the Global Ozone Monitoring Experiment (GOME satellite spectrometer are used to quantify the source strength and 3D distribution of lightning produced nitrogen oxides (NOx=NO2+NO2. A sharp increase of NO2 is observed at convective cloud tops with increasing cloud top height, consistent with a power-law behaviour with power 5±2. Convective production of clouds with the same cloud height are found to produce NO2 with a ratio 1.6/1 for continents compared to oceans. This relation between cloud properties and NO2 is used to construct a 10:30 local time global lightning NO2 production map for 1997. An extensive statistical comparison is conducted to investigate the capability of the TM3 chemistry transport model to reproduce observed patterns of lightning NO2 in time and space. This comparison uses the averaging kernel to relate modelled profiles of NO2 to observed NO2 columns. It exploits a masking scheme to minimise the interference of other NOx sources on the observed total columns. Simulations are performed with two lightning parametrisations, one relating convective preciptation (CP scheme to lightning flash distributions, and the other relating the fifth power of the cloud top height (H5 scheme to lightning distributions. The satellite-retrieved NO2 fields show significant correlations with the simulated lightning contribution to the NO2 concentrations for both parametrisations. Over tropical continents modelled lightning NO2 shows remarkable quantitative agreement with observations. Over the oceans however, the two model lightning parametrisations overestimate the retrieved NO2 attributed to lightning. Possible explanations for these overestimations are discussed. The ratio between satellite-retrieved NO2 and modelled lightning NO2 is used to rescale the original modelled lightning NOx production. Eight estimates of the lightning NOx production in 1997 are obtained from spatial and temporal correlation

  5. Understanding how roadside concentrations of NOx are influenced by the background levels, traffic density, and meteorological conditions using Boosted Regression Trees

    Science.gov (United States)

    Sayegh, Arwa; Tate, James E.; Ropkins, Karl

    2016-02-01

    Oxides of Nitrogen (NOx) is a major component of photochemical smog and its constituents are considered principal traffic-related pollutants affecting human health. This study investigates the influence of background concentrations of NOx, traffic density, and prevailing meteorological conditions on roadside concentrations of NOx at UK urban, open motorway, and motorway tunnel sites using the statistical approach Boosted Regression Trees (BRT). BRT models have been fitted using hourly concentration, traffic, and meteorological data for each site. The models predict, rank, and visualise the relationship between model variables and roadside NOx concentrations. A strong relationship between roadside NOx and monitored local background concentrations is demonstrated. Relationships between roadside NOx and other model variables have been shown to be strongly influenced by the quality and resolution of background concentrations of NOx, i.e. if it were based on monitored data or modelled prediction. The paper proposes a direct method of using site-specific fundamental diagrams for splitting traffic data into four traffic states: free-flow, busy-flow, congested, and severely congested. Using BRT models, the density of traffic (vehicles per kilometre) was observed to have a proportional influence on the concentrations of roadside NOx, with different fitted regression line slopes for the different traffic states. When other influences are conditioned out, the relationship between roadside concentrations and ambient air temperature suggests NOx concentrations reach a minimum at around 22 °C with high concentrations at low ambient air temperatures which could be associated to restricted atmospheric dispersion and/or to changes in road traffic exhaust emission characteristics at low ambient air temperatures. This paper uses BRT models to study how different critical factors, and their relative importance, influence the variation of roadside NOx concentrations. The paper

  6. Sensitivities of NOx transformation and the effects on surface ozone and nitrate

    Directory of Open Access Journals (Sweden)

    H. Lei

    2013-08-01

    Full Text Available As precursors for tropospheric ozone and nitrate aerosols, Nitrogen oxides (NOx in present atmosphere and its transformation in responding to emission and climate perturbations are studied by CAM-Chem model and air quality measurements including National Emission Inventory (NEI, Clean Air Status and Trends Network (CASTNET and Environmental Protection Agency Air Quality System (EPA AQS. It is found that not only the surface ozone formation but also the nitrate formation is associated with the relative emissions of NOx and volatile organic compounds (VOC. Due to the availability of VOC and associated NOx titration, ozone productions in industrial regions increase in warmer conditions and slightly decrease against NOx emission increase, which is converse to the response in farming region. The decrease or small increase in ozone concentrations over industrial regions result in the responded nitrate increasing rate staying above the increasing rate of NOx emissions. It is indicated that ozone concentration change is more directly affected by changes in climate and precursor emissions, while nitrate concentration change is also affected by local ozone production types and their seasonal transfer. The sensitivity to temperature perturbations shows that warmer climate accelerates the decomposition of odd nitrogen (NOy during the night. As a result, the transformation rate of NOx to nitrate decreases. Examinations on the historical emission and air quality records on typical pollution areas further confirm the conclusion drawn from modeling experiments.

  7. The impact of global aviation NOx emissions on tropospheric composition changes from 2005 to 2011

    Science.gov (United States)

    Wasiuk, D. K.; Khan, M. A. H.; Shallcross, D. E.; Lowenberg, M. H.

    2016-09-01

    The impact of aviation NOx emissions from 2005 to 2011 on the chemical composition of the atmosphere has been investigated on the basis of integrations of the 3-D global chemical and transport model, STOCHEM-CRI with the novel CRIv2-R5 chemistry scheme. A base case simulation without aircraft NOx emissions and integrations with NOx emissions from aircraft are inter-compared. The sensitivity of the global atmosphere to varying the quantity and the geographical distribution of the global annual aviation NOx emissions is assessed by performing, for the first time, a series of integrations based on changing the total mass and distribution of aircraft NOx emissions derived from air traffic movements recorded between 2005 and 2011. The emissions of NOx from the global fleet based on actual records of air traffic movements between 2005 and 2011 increased the global tropospheric annual mean burden of O3 by 1.0 Tg and decreased the global tropospheric annual mean burden of CH4 by 2.5 Tg. The net NOy and O3 production increases by 0.5% and 1%, respectively between 2005 and 2011 in total. At cruise altitude, the absolute increase in the modelled O3 mixing ratios is found to be up to 0.7 ppb between 2005 and 2011 at 25°N-50°N.

  8. Transient modelling of heat loading of phase change material for energy storage

    Directory of Open Access Journals (Sweden)

    Asyraf W.M.

    2017-01-01

    Full Text Available As the development of solar energy is getting advance from time to time, the concentration solar technology also get the similar attention from the researchers all around the globe. This technology concentrate a large amount of energy into main spot. To collect all the available energy harvest from the solar panel, a thermal energy storage is required to convert the heat energy to one of the purpose such as electrical energy. With the idea of energy storage application that can be narrow down to commercial application such as cooking stove. Using latent heat type energy storage seem to be appropriate with the usage of phase change material (PCM that can release and absorb heat energy at nearly constant temperature by changing its state. Sodium nitrate (NaNO3 and potassium nitrate (KNO3 was selected to use as PCM in this project. This paper focus on the heat loading process and the melting process of the PCM in the energy storage using a computer simulation. The model of the energy storage was created as solid three dimensional modelling using computer aided software and the geometry size of it depend on how much it can apply to boil 1 kg of water in cooking application. The materials used in the tank, heat exchanger and the heat transfer fluid are stainless steel, copper and XCELTHERM MK1, respectively. The analysis was performed using a commercial simulation software in a transient state. The simulation run on different value of velocity but kept controlled under laminar state only, then the relationship of velocity and heat distribution was studied and the melting process of the PCM also has been analyzed. On the effect of heat transfer fluid velocity, the higher the velocity resulted in higher the rate of heat transfer. The comparison between the melting percentages of the PCMs under test conditions show that NaNO3 melts quite faster than KNO3.

  9. A multicriteria decision analysis model and risk assessment framework for carbon capture and storage.

    Science.gov (United States)

    Humphries Choptiany, John Michael; Pelot, Ronald

    2014-09-01

    Multicriteria decision analysis (MCDA) has been applied to various energy problems to incorporate a variety of qualitative and quantitative criteria, usually spanning environmental, social, engineering, and economic fields. MCDA and associated methods such as life-cycle assessments and cost-benefit analysis can also include risk analysis to address uncertainties in criteria estimates. One technology now being assessed to help mitigate climate change is carbon capture and storage (CCS). CCS is a new process that captures CO2 emissions from fossil-fueled power plants and injects them into geological reservoirs for storage. It presents a unique challenge to decisionmakers (DMs) due to its technical complexity, range of environmental, social, and economic impacts, variety of stakeholders, and long time spans. The authors have developed a risk assessment model using a MCDA approach for CCS decisions such as selecting between CO2 storage locations and choosing among different mitigation actions for reducing risks. The model includes uncertainty measures for several factors, utility curve representations of all variables, Monte Carlo simulation, and sensitivity analysis. This article uses a CCS scenario example to demonstrate the development and application of the model based on data derived from published articles and publicly available sources. The model allows high-level DMs to better understand project risks and the tradeoffs inherent in modern, complex energy decisions.

  10. An XPath-based OWL storage model for effective ontology management in Semantic Web environment

    Institute of Scientific and Technical Information of China (English)

    Jinhyung KIM; Dongwon JEONG; Doo-kwon BAIK

    2009-01-01

    With the rapid growth of the Web, the volume of information on the Web is increasing exponentially. However,information on the current Web is only understandable to humans, and this makes precise information retrieval difficult. To solve this problem, the Semantic Web was proposed. We must use ontology languages that can assign data the semantics for realizing the Semantic Web. One of the representative ontology languages is the Web ontology language OWL, adopted as a recommendation by the World-Wide Web Consortium (W3C). OWL includes hierarchical structural information between classes or properties. Therefore, an efficient OWL storage model that considers a hierarchical structure for effective information retrieval on the Semantic Web is required. In this paper we suggest an XPath-based OWL storage (XPOS) model, which includes hierarchical information between classes or properties in XPath form, and enables intuitive and effective information retrieval. Also, we show the comparative evaluation results for the performance of the XPOS model, Sesame, and the XML file system-based storage (XFSS) model, in terms of query processing and ontology updating.

  11. An Object-Relational Ifc Storage Model Based on Oracle Database

    Science.gov (United States)

    Li, Hang; Liu, Hua; Liu, Yong; Wang, Yuan

    2016-06-01

    With the building models are getting increasingly complicated, the levels of collaboration across professionals attract more attention in the architecture, engineering and construction (AEC) industry. In order to adapt the change, buildingSMART developed Industry Foundation Classes (IFC) to facilitate the interoperability between software platforms. However, IFC data are currently shared in the form of text file, which is defective. In this paper, considering the object-based inheritance hierarchy of IFC and the storage features of different database management systems (DBMS), we propose a novel object-relational storage model that uses Oracle database to store IFC data. Firstly, establish the mapping rules between data types in IFC specification and Oracle database. Secondly, design the IFC database according to the relationships among IFC entities. Thirdly, parse the IFC file and extract IFC data. And lastly, store IFC data into corresponding tables in IFC database. In experiment, three different building models are selected to demonstrate the effectiveness of our storage model. The comparison of experimental statistics proves that IFC data are lossless during data exchange.

  12. Thermocline Storage Filled with Structured Ceramics. Numerical Consistency of the Developed Numerical Model and First Observations

    Science.gov (United States)

    Motte, Fabrice; Bugler-Lamb, Samuel L.; Falcoz, Quentin

    2015-07-01

    The attraction of solar energy is greatly enhanced by the possibility of it being used during times of reduced or non-existent solar flux, such as weather induced intermittences or the darkness of the night. Therefore optimizing thermal storage for use in solar energy plants is crucial for the success of this sustainable energy source. Here we present a study of a structured bed filler dedicated to Thermocline type thermal storage, believed to outweigh the financial and thermal benefits of other systems currently in use such as packed bed Thermocline tanks. Several criterions such as Thermocline thickness and Thermocline centering are defined with the purpose of facilitating the assessment of the efficiency of the tank to complement the standard concepts of power output. A numerical model is developed that reduces to two dimensions the modeling of such a tank. The structure within the tank is designed to be built using simple bricks harboring rectangular channels through which the solar heat transfer and storage fluid will flow. The model is scrutinized and tested for physical robustness, and the results are presented in this paper. The consistency of the model is achieved within particular ranges for each physical variable.

  13. Using interactive recession curve analysis to specify a general catchment storage model

    Directory of Open Access Journals (Sweden)

    R. Lamb

    1997-01-01

    Full Text Available An analysis of hydrograph recessions can be used to identify the parameters of a conceptual catchment storage irnodel and, with the advent of large-scale digital data storage and automated logging systems, it has become desirable to automate recession curve analysis. Various studies have thus reported algorithms used to infer 'baseflow' storage models automatically from recession data. Such algorithms commonly operate by maximising the fit of measured recession data to some a priori function. Here, an alternative approach is taken in which the appropriate form for a catchment saturated zone store is investigated by combining observed recession data to form a Master Recession Curve (MRC. This is done within a software package that offers automated functions to help select recession periods suitable for inclusion within the MRC. These recession periods are combined automatically to form a 'prototype' MRC, which can be modified interactively to overcome problems such as unrepresentative or sparse data. The master recession for a catchment is used to calculate an empirical catchment-averaged discharge-relative storage (QΔS relationship. The method is considered to be general because the QΔS relationship may be of arbitrary form. Examples are given, showing the derivation for three catchments of different QΔS functions.

  14. The role of residence time in diagnostic models of global carbon storage capacity: model decomposition based on a traceable scheme.

    Science.gov (United States)

    Yizhao, Chen; Jianyang, Xia; Zhengguo, Sun; Jianlong, Li; Yiqi, Luo; Chengcheng, Gang; Zhaoqi, Wang

    2015-11-06

    As a key factor that determines carbon storage capacity, residence time (τE) is not well constrained in terrestrial biosphere models. This factor is recognized as an important source of model uncertainty. In this study, to understand how τE influences terrestrial carbon storage prediction in diagnostic models, we introduced a model decomposition scheme in the Boreal Ecosystem Productivity Simulator (BEPS) and then compared it with a prognostic model. The result showed that τE ranged from 32.7 to 158.2 years. The baseline residence time (τ'E) was stable for each biome, ranging from 12 to 53.7 years for forest biomes and 4.2 to 5.3 years for non-forest biomes. The spatiotemporal variations in τE were mainly determined by the environmental scalar (ξ). By comparing models, we found that the BEPS uses a more detailed pool construction but rougher parameterization for carbon allocation and decomposition. With respect to ξ comparison, the global difference in the temperature scalar (ξt) averaged 0.045, whereas the moisture scalar (ξw) had a much larger variation, with an average of 0.312. We propose that further evaluations and improvements in τ'E and ξw predictions are essential to reduce the uncertainties in predicting carbon storage by the BEPS and similar diagnostic models.

  15. State of the art on high temperature thermal energy storage for power generation. Part 1. Concepts, materials and modellization

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Antoni; Medrano, Marc; Martorell, Ingrid; Cabeza, Luisa F. [GREA Innovacio Concurrent, Universitat de Lleida, Pere de Cabrera s/n, 25001-Lleida (Spain); Lazaro, Ana; Dolado, Pablo; Zalba, Belen [Instituto de Investigacion en Ingenieria de Aragon, I3A, Grupo de Ingenieria Termica y Sistemas Energeticos (GITSE), Dpto. Ingenieria Mecanica, Area de Maquinas y Motores Termicos, Universidad de Zaragoza, Campus Politecnico Rio Ebro, Edificio ' Agustin de Betancourt' , Maria de Luna s/n, 50018 Zaragoza (Spain)

    2010-01-15

    Concentrated solar thermal power generation is becoming a very attractive renewable energy production system among all the different renewable options, as it has have a better potential for dispatchability. This dispatchability is inevitably linked with an efficient and cost-effective thermal storage system. Thus, of all components, thermal storage is a key one. However, it is also one of the less developed. Only a few plants in the world have tested high temperature thermal energy storage systems. In this paper, the different storage concepts are reviewed and classified. All materials considered in literature or plants are listed. And finally, modellization of such systems is reviewed. (author)

  16. Experimental challenges to theories of classical conditioning: application of an attentional model of storage and retrieval.

    Science.gov (United States)

    Schmajuk, Nestor A; Larrauri, José A

    2006-01-01

    Several studies have recently challenged the accuracy of traditional models of classical conditioning that account for some experimental data in terms of a storage deficit. Among other results, it has been reported that extinction of the blocking or overshadowing stimulus results in the recovery of the response to the blocked or overshadowed stimulus, backward blocking shows spontaneous recovery, extinction of the training context results in the recovery from latent inhibition, interposing a delay between conditioning and testing in latent inhibition increases latent inhibition, and latent inhibition antagonizes overshadowing. An existing neural network model of classical conditioning (N. A. Schmajuk, Y. Lam, & J. A. Gray, 1996), which includes an attentional mechanism controlling both storage and retrieval of associations, is able to quantitatively describe these results.

  17. Seasonal thermal energy storage in unsaturated soils: Model development and field validation

    Energy Technology Data Exchange (ETDEWEB)

    Doughty, C.; Nir, Aharon, Tsang, Chin-Fu

    1991-06-01

    This report summarizes ten years of activity carried out at the Earth Sciences Division of the Lawrence Berkeley Laboratory (LBI) in the subject of seasonal storage of thermal energy in unsaturated soils. The objectives of the work were to make a conceptual study of this type of storage, to offer guidelines for planning and evaluation of the method, to produce models and simulation for an actual field experiment, to participate in an on-line data analysis of experimental results. and to evaluate the results in terms of the validation of the concept, models and the experimental techniques. The actual field experiments were performed in Beer-Sheva, Israel. Details of engineering and field operations are not included in this report.

  18. Modelling the Size of Seasonal Thermal Storage in the Solar District Heating System

    Directory of Open Access Journals (Sweden)

    Giedrė Streckienė

    2012-12-01

    Full Text Available The integration of a thermal storage system into the solar heating system enables to increase the use of solar thermal energy in buildings and allows avoiding the mismatch between consumers’ demand and heat production in time. The paper presents modelling a seasonal thermal storage tank various sizes of which have been analyzed in the district solar heating system that could cover a part of heat demand for the district of individual houses in Vilnius. A biomass boiler house, as an additional heat source, should allow covering the remaining heat demand. energyPRO software is used for system modelling. The paper evaluates heat demand, climate conditions and technical characteristics.Article in Lithuanian

  19. Mixed Integer Programming Model and Incremental Optimization for Delivery and Storage Planning Using Truck Terminals

    Science.gov (United States)

    Sakakibara, Kazutoshi; Tian, Yajie; Nishikawa, Ikuko

    We discuss the planning of transportation by trucks over a multi-day period. Each truck collects loads from suppliers and delivers them to assembly plants or a truck terminal. By exploiting the truck terminal as a temporal storage, we aim to increase the load ratio of each truck and to minimize the lead time for transportation. In this paper, we show a mixed integer programming model which represents each product explicitly, and discuss the decomposition of the problem into a problem of delivery and storage, and a problem of vehicle routing. Based on this model, we propose a relax-and-fix type heuristic in which decision variables are fixed one by one by mathematical programming techniques such as branch-and-bound methods.

  20. Glycogen Storage Disease Type Ia in Canines: A Model for Human Metabolic and Genetic Liver Disease

    Directory of Open Access Journals (Sweden)

    Andrew Specht

    2011-01-01

    Full Text Available A canine model of Glycogen storage disease type Ia (GSDIa is described. Affected dogs are homozygous for a previously described M121I mutation resulting in a deficiency of glucose-6-phosphatase-α. Metabolic, clinicopathologic, pathologic, and clinical manifestations of GSDIa observed in this model are described and compared to those observed in humans. The canine model shows more complete recapitulation of the clinical manifestations seen in humans including “lactic acidosis”, larger size, and longer lifespan compared to other animal models. Use of this model in preclinical trials of gene therapy is described and briefly compared to the murine model. Although the canine model offers a number of advantages for evaluating potential therapies for GSDIa, there are also some significant challenges involved in its use. Despite these challenges, the canine model of GSDIa should continue to provide valuable information about the potential for generating curative therapies for GSDIa as well as other genetic hepatic diseases.

  1. Toward improved catalytic low-temperature NOx removal in diesel-powered vehicles.

    Science.gov (United States)

    Klingstedt, Fredrik; Arve, Kalle; Eränen, Kari; Murzin, Dmitry Yu

    2006-04-01

    The potential of different catalytic after treatment techniques to meet future diesel emission standards, which are strongly shifted toward urban driving conditions including cold start, are critically discussed in this Account and evaluated for their suitability for commercial applications. The dominating techniques in this field are NO(x) storage, urea-selective catalytic reduction (SCR), and HC-SCR. Each of these techniques have significant disadvantages such as sulfur sensitiveness and regeneration requirements of NO(x)-storage materials, infrastructure issues and formation of ammonium nitrate (at low temperatures) for urea-SCR, and low-temperature activity of HC-SCR catalysts. Ways to overcome these disadvantages in commercial applications may involve optimized regeneration strategies, reactor modifications, flow reversal, closed-loop NO(x) feedback systems, nonthermal plasma, and/or hydrogen-assisted catalyses, etc.

  2. Finite Element Method Modeling of Sensible Heat Thermal Energy Storage with Innovative Concretes and Comparative Analysis with Literature Benchmarks

    Directory of Open Access Journals (Sweden)

    Claudio Ferone

    2014-08-01

    Full Text Available Efficient systems for high performance buildings are required to improve the integration of renewable energy sources and to reduce primary energy consumption from fossil fuels. This paper is focused on sensible heat thermal energy storage (SHTES systems using solid media and numerical simulation of their transient behavior using the finite element method (FEM. Unlike other papers in the literature, the numerical model and simulation approach has simultaneously taken into consideration various aspects: thermal properties at high temperature, the actual geometry of the repeated storage element and the actual storage cycle adopted. High-performance thermal storage materials from the literatures have been tested and used here as reference benchmarks. Other materials tested are lightweight concretes with recycled aggregates and a geopolymer concrete. Their thermal properties have been measured and used as inputs in the numerical model to preliminarily evaluate their application in thermal storage. The analysis carried out can also be used to optimize the storage system, in terms of thermal properties required to the storage material. The results showed a significant influence of the thermal properties on the performances of the storage elements. Simulation results have provided information for further scale-up from a single differential storage element to the entire module as a function of material thermal properties.

  3. Neuro-fuzzy modeling to predict physicochemical and microbiological parameters of partially dried cherry tomato during storage: effects on water activity, temperature and storage time.

    Science.gov (United States)

    Tao, Yang; Li, Yong; Zhou, Ruiyun; Chu, Dinh-Toi; Su, Lijuan; Han, Yongbin; Zhou, Jianzhong

    2016-10-01

    In the study, osmotically dehydrated cherry tomatoes were partially dried to water activity between 0.746 and 0.868, vacuum-packed and stored at 4-30 °C for 60 days. Adaptive neuro-fuzzy inference system (ANFIS) was utilized to predict the physicochemical and microbiological parameters of these partially dried cherry tomatoes during storage. Satisfactory accuracies were obtained when ANFIS was used to predict the lycopene and total phenolic contents, color and microbial contamination. The coefficients of determination for all the ANFIS models were higher than 0.86 and showed better performance for prediction compared with models developed by response surface methodology. Through ANFIS modeling, the effects of storage conditions on the properties of partially dried cherry tomatoes were visualized. Generally, contents of lycopene and total phenolics decreased with the increase in water activity, temperature and storage time, while aerobic plate count and number of yeasts and molds increased at high water activities and temperatures. Overall, ANFIS approach can be used as an effective tool to study the quality decrease and microbial pollution of partially dried cherry tomatoes during storage, as well as identify the suitable preservation conditions.

  4. Calibration of the Nonlinear Accelerator Model at the Diamond Storage Ring

    CERN Document Server

    Bartolini, Riccardo; Rowland, James; Martin, Ian; Schmidt, Frank

    2010-01-01

    The correct implementation of the nonlinear ring model is crucial to achieve the top performance of a synchrotron light source. Several dynamics quantities can be used to compare the real machine with the model and eventually to correct the accelerator. Most of these methods are based on the analysis of turn-by-turn data of excited betatron oscillations. We present the experimental results of the campaign of measurements carried out at the Diamond. A combination of Frequency Map Analysis (FMA) and detuning with momentum measurements has allowed a precise calibration of the nonlinear model capable of reproducing the nonlinear beam dynamics in the storage ring

  5. Effect of Steam Addition on the Flow Field and NOx Emissions for Jet-A in an Aircraft Combustor

    Science.gov (United States)

    Xue, Rui; Hu, Chunbo; Nikolaidis, Theoklis; Pilidis, Pericle

    2016-12-01

    The steam injection technology for aircraft engines is gaining rising importance because of the strong limitations imposed by the legislation for NOx reduction in airports. In order to investigate the impact of steam addition on combustion and NOx emissions, an integrated performance-CFD-chemical reactor network (CRN) methodology was developed. The CFD results showed steam addition reduced the high temperature size and the radical pool moved downstream. Then different post-processing techniques are employed and CRN is generated to predict NOx emissions. This network consists of 14 chemical reactor elements and the results were in close agreement with the ICAO databank. The established CRN model was then used for steam addition study and the results showed under air/steam mixture atmosphere, high steam content could push the NOx formation region to the post-flame zone and a large amount of the NOx emission could be reduced when the steam mass fraction is quite high.

  6. Thermo-hydro-mechanical modeling and analysis of cement-based energy storages for small-scale dwellings

    Science.gov (United States)

    Hailemariam, Henok; Wuttke, Frank

    2016-04-01

    One of the common technologies for balancing the energy demand and supply in district heating, domestic hot water production, thermal power plants and thermal process industries in general is thermal energy storage. Thermal energy storage, in particular sensible heat storage as compared to latent heat storage and thermo-chemical storage, has recently gained much interest in the renewable energy storage sector due to its comparatively low cost and technical development. Sensible heat storages work on the principle of storing thermal energy by raising or lowering the temperature of liquid (commonly water) or solid media, and do not involve material phase change or conversion of thermal energy by chemical reactions or adsorption processes as in latent heat and thermo-chemical storages, respectively. In this study, the coupled thermo-hydro-mechanical behaviour of a cement-based thermal energy storage system for domestic applications has been modeled in both saturated as well as unsaturated conditions using the Finite Element method along with an extensive experimental analysis program for parameter detection. For this purpose, a prototype model is used with three well-known thermal energy storage materials, and the temperature and heat distribution of the system were investigated under specific thermo-hydro-mechanical conditions. Thermal energy samples with controlled water to solids ratio and stored in water for up to 28 days were used for the experimental program. The determination of parameters included: thermal conductivity, specific heat capacity and linear coefficient of thermal expansion (CTE) using a transient line-source measurement technique as well as a steady-state thermal conductivity and expansion meter; mechanical strength parameters such as uni-axial strength, young's modulus of elasticity, poisson's ratio and shear parameters using uniaxial, oedometer and triaxial tests; and hydraulic properties such as hydraulic permeability or conductivity under

  7. Improvement of LSM15-CGO10 electrodes for electrochemical removal of NOx by KNO3 and MnOx impregnation

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Kammer Hansen, Kent

    2011-01-01

    in 1000 ppm NO, 10% O2 and 1000 ppm NO + 10% O2 in the temperature range 300-500 °C and the electrodes were investigated by scanning electron microscopy before and after testing. At 400-450 °C a NOx-storage process was observed on the KNO3-impregnated electrodes, this process appeared to be dependent...

  8. Resource Storage Management Model For Ensuring Quality Of Service In The Cloud Archive Systems

    Directory of Open Access Journals (Sweden)

    Mariusz Kapanowski

    2014-01-01

    Full Text Available Nowadays, service providers offer a lot of IT services in the public or private cloud. The client can buy various kinds of services like SaaS, PaaS, etc. Recently there was introduced Backup as a Service (BaaS as a variety of SaaS. At the moment there are available several different BaaSes for archiving the data in the cloud, but they provide only a basic level of service quality. In the paper we propose a model which ensures QoS for BaaS and some  methods for management of storage resources aimed at achieving the required SLA. This model introduces a set of parameters responsible for SLA level which can be offered on the basic or higher level of quality. The storage systems (typically HSM, which are distributed between several Data Centres,  are built based on disk arrays, VTLs, and tape libraries. The RSMM model does not assume bandwidth reservation or control, but is rather focused on the management of storage resources.

  9. Modelling Concentrating Solar Power with Thermal Energy Storage for Integration Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Hummon, M.; Denholm, P.; Jorgenson, J.; Mehos, M.

    2013-10-01

    Concentrating solar power with thermal energy storage (CSP-TES) can provide multiple benefits to the grid, including low marginal cost energy and the ability to levelize load, provide operating reserves, and provide firm capacity. It is challenging to properly value the integration of CSP because of the complicated nature of this technology. Unlike completely dispatchable fossil sources, CSP is a limited energy resource, depending on the hourly and daily supply of solar energy. To optimize the use of this limited energy, CSP-TES must be implemented in a production cost model with multiple decision variables for the operation of the CSP-TES plant. We develop and implement a CSP-TES plant in a production cost model that accurately characterizes the three main components of the plant: solar field, storage tank, and power block. We show the effect of various modelling simplifications on the value of CSP, including: scheduled versus optimized dispatch from the storage tank and energy-only operation versus co-optimization with ancillary services.

  10. Pathological features of glycogen storage disease type II highlighted in the knockout mouse model.

    Science.gov (United States)

    Bijvoet, A G; Van Hirtum, H; Vermey, M; Van Leenen, D; Van Der Ploeg, A T; Mooi, W J; Reuser, A J

    1999-11-01

    Glycogen storage disease type II (GSDII; Pompe's disease) is an autosomal recessive disease caused by lysosomal alpha-glucosidase deficiency. Skeletal muscle weakness is the most conspicuous clinical symptom of patients suffering from GSDII and skeletal muscle also is prominently involved in the knockout mouse model of this disease. Thus far, however, little detailed information has been published on the pathological changes in other mouse tissues. This paper aims to provide these data and gives a record of the clinical course of the mouse model over a 2-year period. Four-month-old affected mice perform worse in a running wheel than their unaffected littermates, but do not yet display other clear signs of disease. The lysosomal glycogen storage, already evident at birth, becomes more severe in time, leading to muscle wasting by 9-10 months of age and then limb girdle weakness and kyphosis. The disease does not markedly shorten the animal's life span despite the serious tissue pathology, which is not limited to heart and skeletal muscle, but is also seen in the smooth muscle of blood vessels and of the respiratory, digestive, and urogenital tracts. In addition, the mice have lysosomal glycogen storage in the liver, kidney, spleen, and salivary gland; in Schwann cells of the peripheral nerves, and in a subset of neurons in the central nervous system. By pathological criteria, the knockout mouse model parallels the human infantile form of GSDII and is attractive for studying the possible reversal of tissue pathology and symptomatology under different therapeutic regimes.

  11. Degradation kinetic modelling of ascorbic acid and colour intensity in pasteurised blood orange juice during storage.

    Science.gov (United States)

    Remini, Hocine; Mertz, Christian; Belbahi, Amine; Achir, Nawel; Dornier, Manuel; Madani, Khodir

    2015-04-15

    The stability of ascorbic acid and colour intensity in pasteurised blood orange juice (Citrus sinensis [L.] Osbeck) during one month of storage was investigated at 4-37 °C. The effects of ascorbic acid fortification (at 100, 200 mg L(-1)) and deaeration, temperature/time storage on the kinetic behaviour were determined. Ascorbic acid was monitored by HPLC-DAD and colour intensity by spectrophotometric measurements. Degradation kinetics were best fitted by first-order reaction models for both ascorbic acid and colour intensity. Three models (Arrhenius, Eyring and Ball) were used to assess the temperature-dependent degradation. Following the Arrhenius model, activation energies were ranged from 51 to 135 kJ mol(-1) for ascorbic acid and from 49 to 99 kJ mol(-1) for colour intensity. The effect of storage temperature and deaeration are the most influent factors on kinetics degradation, while the fortification revealed no significant effect on ascorbic acid content and colour intensity.

  12. Controls over Ocean Mesopelagic Interior Carbon Storage (COMICS: fieldwork, synthesis and modelling efforts

    Directory of Open Access Journals (Sweden)

    Richard John Sanders

    2016-08-01

    Full Text Available The ocean’s biological carbon pump plays a central role in regulating atmospheric CO2 levels. In particular, the depth at which sinking organic carbon is broken down and respired in the mesopelagic zone is critical, with deeper remineralisation resulting in greater carbon storage. Until recently, however, a balanced budget of the supply and consumption of organic carbon in the mesopelagic had not been constructed in any region of the ocean, and the processes controlling organic carbon turnover are still poorly understood. Large-scale data syntheses suggest that a wide range of factors can influence remineralisation depth including upper-ocean ecological interactions, and interior dissolved oxygen concentration and temperature. However these analyses do not provide a mechanistic understanding of remineralisation, which increases the challenge of appropriately modelling the mesopelagic carbon dynamics. In light of this, the UK Natural Environment Research Council has funded a programme with this mechanistic understanding as its aim, drawing targeted fieldwork right through to implementation of a new parameterisation for mesopelagic remineralisation within an IPCC class global biogeochemical model. The Controls over Ocean Mesopelagic Interior Carbon Storage (COMICS programme will deliver new insights into the processes of carbon cycling in the mesopelagic zone and how these influence ocean carbon storage. Here we outline the programme’s rationale, its goals, planned fieldwork and modelling activities, with the aim of stimulating international collaboration.

  13. Transport of atmospheric NOx and HNO3 over Cape Town

    Science.gov (United States)

    Abiodun, B. J.; Ojumu, A. M.; Jenner, S.; Ojumu, T. V.

    2013-05-01

    Cape Town, the most popular tourist city in Africa, usually experiences air pollution with unpleasant odour in winter. Previous studies have associated the pollution with local emission of pollutants within the city. The present study examines the transport of atmospheric pollutants (NOx and HNO3) over South Africa and shows how the transport of pollutants from the Mpumalanga Highveld may contribute to the pollution in Cape Town. The study analysed observation data (2001-2008) from Cape Town air quality network and simulation data (2001-2004) from regional climate model (RegCM4) over southern Africa. The simulation accounts for the influence of complex topography, atmospheric condition, and atmospheric chemistry on emission and transport of pollutants over southern Africa. Flux budget analysis was used to examine whether Cape Town is a source or sink for NOx and HNO3 during the extreme pollution events. The results show that extreme pollution events over Cape Town are associated with the low-level (surface-850 hPa) transport of NOx from the Mpumalanga Highveld to Cape Town, and with a tongue of high concentration of HNO3 that extends from the Mpumalanga Highveld to Cape Town along the south coast of South Africa. The prevailing atmospheric conditions during the extreme pollution events feature an upper-level (700 hPa) anticyclonic flow over South Africa and a low-level col over Cape Town. The anticyclonic flow induces a strong subsidence motion, which prevents vertical mixing of the pollutants and caps high concentration of pollutants close to the surface as they are transported from the Mpumalanga Highveld toward Cape Town, while the col accumulates the pollutants over the city. This study shows that Cape Town can be a sink for the NOx and HNO3 during extreme pollution events and suggests that the accumulation of pollutants transported from other areas (e.g. Mpumalanga Highveld) may contribute substantially to the air pollution in Cape Town.

  14. NOx and NOy in the Tropical Marine Boundary Layer

    Science.gov (United States)

    Reed, Chris; Evans, Mathew J.; Lee, James D.; Carpenter, Lucy J.; Read, Katie A.; Mendes, Luis N.

    2016-04-01

    Nitrogen oxides (NOx=NO+NO2) and their reservoir species (NOy) play a central role in determining the chemistry of the troposphere. Although their concentrations are low (1-100 ppt) in regions such as the remote marine boundary layer, they have a profound impact on ozone production and the oxidizing capacity. There are very few observations of NOx and NOy in remote oceanic regions due to the technical challenges of measuring such low concentrations, and thus our understanding of this background chemistry is incomplete. Here we present long term measurements of NOx (2006-2015) and more recent measurements of speciated NOy (total peroxyacetyl nitrates, PANs; alkyl nitrates, ANs; nitric acid; and aerosol analogues) made at the Cape Verde Atmospheric Observatory (CVAO; 16° 51' N, 24° 52' W) located in the tropical Atlantic Ocean. We identify potential interferences in the NO2 and NOy measurements and methods to eliminate them. Diurnal and seasonal cycles are interpreted using a box model. We find a complex chemistry with interactions between organic and inorganic chemistry, between the aerosol and gas phase, and between the very local and large scales.

  15. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Marc Cremer; Kevin Davis; Martin Denison; Adel Sarofim; Connie Senior; Hong-Shig Shim; Dave Swenson; Bob Hurt; Eric Suuberg; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker

    2006-06-30

    This is the Final Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project was to develop cost-effective analysis tools and techniques for demonstrating and evaluating low-NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) provided co-funding for this program. This project included research on: (1) In furnace NOx control; (2) Impacts of combustion modifications on boiler operation; (3) Selective Catalytic Reduction (SCR) catalyst testing and (4) Ammonia adsorption/removal on fly ash. Important accomplishments were achieved in all aspects of the project. Rich Reagent Injection (RRI), an in-furnace NOx reduction strategy based on injecting urea or anhydrous ammonia into fuel rich regions in the lower furnace, was evaluated for cyclone-barrel and PC fired utility boilers. Field tests successfully demonstrated the ability of the RRI process to significantly reduce NOx emissions from a staged cyclone-fired furnace operating with overfire air. The field tests also verified the accuracy of the Computational Fluid Dynamic (CFD) modeling used to develop the RRI design and highlighted the importance of using CFD modeling to properly locate and configure the reagent injectors within the furnace. Low NOx firing conditions can adversely impact boiler operation due to increased waterwall wastage (corrosion) and increased soot production. A corrosion monitoring system that uses electrochemical noise (ECN) corrosion probes to monitor, on a real-time basis, high temperature corrosion events within the boiler was evaluated. Field tests were successfully conducted at two plants. The Ohio Coal Development Office provided financial assistance to perform the field tests. To investigate soot behavior, an advanced model to predict soot production and destruction was implemented into an existing reacting CFD modeling tool. Comparisons between experimental data collected

  16. Worldwide biogenic soil NOx emissions inferred from OMI NO2 observations

    Directory of Open Access Journals (Sweden)

    G. C. M. Vinken

    2014-06-01

    Full Text Available Biogenic NOx emissions from soils are a large natural source with substantial uncertainties in global bottom-up estimates (ranging from 4 to 27 Tg N yr−1. We reduce this range in emission estimates, and present a top-down soil NOx emission inventory for 2005 based on retrieved tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI. We used a state-of-science soil NOx emission inventory (Hudman et al., 2012 as a priori in the GEOS-Chem chemistry transport model to identify 11 regions where tropospheric NO2 columns are dominated by soil NOx emissions. Strong correlations between soil NOx emissions and simulated NO2 columns indicated that spatial patterns in simulated NO2 columns in these regions indeed reflect the underlying soil NOx emissions. Subsequently, we used a mass-balance approach to constrain emissions for these 11 regions on all major continents using OMI observed and GEOS-Chem simulated tropospheric NO2 columns. We found that responses of simulated NO2 columns to changing NOx emissions were suppressed over low NOx regions, and accounted for these non-linearities in our inversion approach. In general, our approach suggests that emissions need to be increased in most regions. Our OMI top-down soil NOx inventory amounts to 10.0 Tg N for 2005 when only constraining the 11 regions, and 12.9 Tg N when extrapolating the constraints globally. Substantial regional differences exist (ranging from −40% to +90%, and globally our top-down inventory is 4–35% higher than the GEOS-Chem a priori (9.6 Tg N yr−1. We evaluated NO2 concentrations simulated with our new OMI top-down inventory against surface NO2 measurements from monitoring stations in Africa, the USA, and Europe. Although this comparison is complicated by several factors, we find an encouraging improved agreement when using the OMI top-down inventory compared to using the a priori inventory. To our knowledge, this study provides, for the first time, specific constraints

  17. Kinetics of ozone and nitric oxides in dielectric barrier discharges in O2/NOx and N2/O2/NOx mixtures

    Science.gov (United States)

    Stefanovic, I.; Bibinov, N. K.; Deryugin, A. A.; Vinogradov, I. P.; Napartovich, A. P.; Wiesemann, K.

    2001-08-01

    Concentrations of NO, NO2, NO3, N2O5, and O3 were measured by classical absorption spectroscopy in dielectric barrier discharges in flowing O2/NOx and N2/O2/NOx mixtures. The results of measurements in different parts of the discharge chamber and in its exhaust are compared to a numerical zero-dimensional kinetic model and good agreement is found. The experimentally found upper limit of the NOx concentration allowing ozone production is confirmed by the kinetic calculations for both gas mixtures. The rotational temperature of different nitrogen bands was measured by high-resolution emission spectroscopy. The results are explained on the basis of a simplified model and related to the gas temperature in the microdischarge channel and the surrounding gas.

  18. Fractured rock modeling in the National Waste Terminal Storage Program: a review of requirements and status

    Energy Technology Data Exchange (ETDEWEB)

    St. John, C.; Krug, A.; Key, S.; Monsees, J.

    1983-05-01

    Generalized computer codes capable of forming the basis for numerical models of fractured rock masses are being used within the NWTS program. Little additional development of these codes is considered justifiable, except in the area of representation of discrete fractures. On the other hand, model preparation requires definition of medium-specific constitutive descriptions and site characteristics and is therefore legitimately conducted by each of the media-oriented projects within the National Waste Terminal Storage program. However, it is essential that a uniform approach to the role of numerical modeling be adopted, including agreement upon the contribution of modeling to the design and licensing process and the need for, and means of, model qualification for particular purposes. This report discusses the role of numerical modeling, reviews the capabilities of several computer codes that are being used to support design or performance assessment, and proposes a framework for future numerical modeling activities within the NWTS program.

  19. Key chemical NOx sink uncertainties and how they influence top-down emissions of nitrogen oxides

    Directory of Open Access Journals (Sweden)

    T. Stavrakou

    2013-03-01

    Full Text Available Triggered by recent developments from laboratory and field studies regarding major NOx sink pathways in the troposphere, this study evaluates the influence of chemical uncertainties in NOx sinks for global NOx distributions calculated by the IMAGESv2 chemistry-transport model, and quantifies their significance for top-down NOx emission estimates. Our study focuses on four key chemical parameters believed to be of primary importance, more specifically, the rate of the reaction of NO2 with OH radicals, the newly-identified HNO3-forming channel in the reaction of NO with HO2, the reactive uptake of N2O5 on aerosols, and the regeneration of OH in the oxidation of isoprene. Sensitivity simulations are performed to estimate the impact of each source of uncertainty. The model calculations show that, although the NO2 + OH reaction is the largest NOx sink globally accounting for 50–70% of the total sink, the reaction contributing the most to the overall uncertainty is the formation of HNO3 in NO + HO2, leading to NOx column changes reaching a~factor of two over tropical regions, and to a 35% decrease in the global tropospheric NOx lifetime. Emission inversion experiments are carried out using model settings which either miminize (MINLOSS or maximize (MAXLOSS the total NOx sink, both constrained by one year of OMI NO2 column data from the DOMINO v2 KNMI algorithm. The choice of the model setup is found to have a major impact on the top-down flux estimates, with 50% higher emissions for MAXLOSS compared to the MINLOSS inversion globally. Even larger departures are found for soil NO (factor of 2 and lightning (70%, whereas the global anthropogenic source is comparatively better constrained, especially in China. Evaluation of the emission optimization is performed against independent satellite observations from the SCIAMACHY sensor, airborne NO2 measurements, observed NOx lifetimes at megacities, as well as with two new bottom-up inventories of

  20. Simulation of NOx emission in circulating fluidized beds burning low-grade fuels

    Energy Technology Data Exchange (ETDEWEB)

    Afsin Gungor [Nigde University, Nigde (Turkey). Faculty of Engineering and Architecture

    2009-05-15

    Nitrogen oxides are a major environmental pollutant resulting from combustion. This paper presents a modeling study of pollutant NOx emission resulting from low-grade fuel combustion in a circulating fluidized bed. The simulation model accounts for the axial and radial distribution of NOx emission in a circulating fluidized bed (CFB). The model results are compared with and validated against experimental data both for small-size and industrial-size CFBs that use different types of low-grade fuels given in the literature. The present study proves that CFB combustion demonstrated by both experimental data and model predictions produces low and acceptable levels of NOx emissions resulting from the combustion of low-grade fuels. Developed model can also investigate the effects of different operational parameters on overall NOx emission. As a result of this investigation, both experimental data and model predictions show that NOx emission increases with the bed temperature but decreases with excess air if other parameters are kept unchanged. 37 refs., 5 figs., 5 tabs.

  1. A Metadata Based Storage Model for Securing Data in Cloud Environment

    Directory of Open Access Journals (Sweden)

    S. Subashini

    2012-01-01

    Full Text Available Problem statement: Enterprises are migrating to the cloud environment at a faster pace. Security of information that is being processed by the applications and ultimately getting stored in the data centers are of big concerns of this newly evolving environment. The security of the data is a concern not only during transferring of data through the wires but also during its storage phase where data stays most of the time. Approach: In order to keep the data secure during its storage phase, a preventive, robust security model is required. Instead of developing a robust security module to prevent hackers from intruding into data centers, a model which will prevent intruders from getting the required information even at the event of intrusion, will be of utmost use. Conventional security models secure data by encryption or by fragmentation. A security model developed using a fragmentation technique that is based on the sensitivity, criticality and value of the data provides better security by means of disintegration of value of the data and also a good technique for prevention of information leaks. The proposed method also provides solutions to access the fragmented data. Results: The proposed model provides a efficient security solution for data stored in cloud. When compared to conventional methods, the speed of data queries are less for small databases, but prove to be very efficient for huge databases. Conclusion: This model provides an efficient solution for data storage security in cloud environment. This technique coupled with standard encryption techniques will make this model more robust.

  2. Response of lightning NOx emissions and ozone production to climate change:Insights from the Atmospheric Chemistry and Climate Model Intercomparison Project

    OpenAIRE

    2016-01-01

    Results from an ensemble of models are used to investigate the response of lightning nitrogen oxide emissions to climate change and the consequent impacts on ozone production. Most models generate lightning using a parameterization based on cloud top height. With this approach and a present-day global emission of 5 TgN, we estimate a linear response with respect to changes in global surface temperature of +0.44 ± 0.05 TgN K−1. However, two models using alternative approaches give +0.14 and −0...

  3. Wind power integration with heat pumps, heat storages, and electric vehicles - Energy systems analysis and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hedegaard, K.

    2013-09-15

    This PhD investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing research, the main focus is put on individual heat pumps in the residential sector (one-family houses) and the possibilities for flexible operation, using the heat storage options available. Several energy systems analyses are performed using the energy system models, Balmorel, developed at the former TSO, ElkraftSystem, and, EnergyPLAN, developed at Aalborg University. The Danish energy system towards 2030, with wind power penetrations of up to 60 %, is used as a case study in most of the analyses. Both models have been developed further, resulting in an improved representation of individual heat pumps and heat storages. An extensive model add-on for Balmorel renders it possible to optimise investment and operation of individual heat pumps and different types of heat storages, in integration with the energy system. Total costs of the energy system are minimised in the optimisation. The add-on incorporates thermal building dynamics and covers various different heat storage options: intelligent heat storage in the building structure for houses with radiator heating and floor heating, respectively, heat accumulation tanks on the space heating circuit, as well as hot water tanks. In EnergyPLAN, some of the heat storage options have been modelled in a technical optimisation that minimises fuel consumption of the energy system and utilises as much wind power as possible. The energy systems analyses reveal that in terms of supporting wind power integration, the installation of individual heat pumps is an important step, while adding heat storages to the heat pumps is less influential. When equipping the heat pumps with heat storages, only moderate system benefits can be gained. Hereof, the main system benefit is that the need for peak/reserve capacity investments can be reduced through peak load shaving; in

  4. Impacts of the abolition of NOx emission trade; Effecten van de afschaffing van NOx- emissiehandel

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, P. [ECN Beleidsstudies, Petten (Netherlands)

    2012-09-15

    The consequences of abolishing the NOx emission trade have been analyzed for the installations that are covered by BEMS legislation (Dutch decree on emission limits for medium-sized combustion plants). The following aspects have been analyzed: What are the enforcement costs if these installations need to comply with BEMS requirements as of 2014?; How are these costs distributed across the various sectors and in particular for the sectors of onshore/offshore gas and oil extraction, greenhouse horticulture and hospitals?; To what extent can costs be lowered by allowing a 2-,3- or 5-year delay of the implementation date for existing installations in BEMS? To answer the above questions, data were used from the NEA (Netherlands Emission Authority) at sector level. Model calculations were conducted to determine the costs and effects [Dutch] De gevolgen van de afschaffing van NOx-emissiehandel zijn geanalyseerd voor het installatiepark dat terugvalt op BEMS-wetgeving (Besluit emissie-eisen middelgrote stookinstallaties). De volgende zaken zijn geanalyseerd: Wat zijn de nalevingskosten indien vanaf 2014 deze installaties aan de BEMS-eisen moeten voldoen?; Hoe zijn deze kosten verdeeld over de verschillende sectoren en in het bijzonder voor de sectoren offshore/onshore gas- en oliewinning, de glastuinbouw en ziekenhuizen?; In hoeverre zijn de kosten te verlagen door 2, 3 of 5 jaar uitstel te geven ten opzichte van de implementatiedatum voor bestaande installaties in BEMS? Voor het beantwoorden van de bovenstaande vragen is gebruik gemaakt van gegevens van de NEa (Nederlandse Emissie autoriteit) op sectorniveau. Met modelberekeningen zijn hiermee kosten en effecten bepaald.

  5. A model of growth and carbon storage in Eriophorum Vaginatum L.

    Science.gov (United States)

    Curasi, S. R.; Rocha, A. V.; Bolster, D.; Fetcher, N.; Parker, T.

    2016-12-01

    Eriophorum Vaginatum L. is a rhizomatous, tussock forming, perennial sedge commonly found in Arctic tundra environments. Tussocks are well suited to harsh nutrient poor environments and tussock tundra is common in Alaska, Canada and Northeastern Russia accounting for 24% of Arctic land area. Tussocks play important roles in Arctic ecosystem biogeochemistry and C storage. However, the environmental and biological factors controlling their size, distribution across the landscape and growth are poorly understood as a result of their growth form and slow growth rate ( 150 years). In order to better understand the role of tussocks in tussock tundra ecosystem C stocks and the potential impacts of climate change on tussock tundra we amassed data from a core site at Toolik field station in North Slope Alaska as well as other Arctic locations. Using this information we constructed a model of carbon storage and growth in E. Vaginatum. We conclude that environmental conditions and the physical properties of the tussock growth form control the rate of tussock growth and retention of C. This work highlights the role of plant growth forms in the retention of tundra ecosystem C stocks. It also has broader applicability to those interested in predicating the impacts of climate change and shifts in vegetation species composition on C storage and fuel loading as well as broader vegetation modeling efforts in tundra ecosystems.

  6. Experimental modelling of the dipole magnet for the electron storage ring DELSY

    CERN Document Server

    Meshkov, I N; Syresin, E M

    2003-01-01

    In the Joint Institute for Nuclear Research (Dubna) the project of Dubna Electron Synchrotron (DELSY) with an electron energy of 1.2 GeV is developed. The electron storage ring in the DELSY project is planned to be created on the basis of magnetic elements, which were used earlier in the storage ring AmPS (NIKHEF, Amsterdam). The optics of the ring is necessary to be changed, its perimeter to be reduced approximately in one and a half time, the energy of electrons to be increased. The paper is devoted to the development of a modified dipole magnet of the storage ring. The preliminary estimation of geometry of the magnet pole is carried out by means of computer modelling using two- and three- dimensional codes of the magnetic field calculation SUPERFISH and RADIA. The experimental stand for the measurements of the dipole magnetic field is described. As the result of calculational and experimental modelling for the dipole magnet, the geometry of its poles was estimated, providing in the horizontal aperture +- 3...

  7. Correlation between enzyme activity and substrate storage in a cell culture model system for Gaucher disease.

    Science.gov (United States)

    Schueler, U H; Kolter, T; Kaneski, C R; Zirzow, G C; Sandhoff, K; Brady, R O

    2004-01-01

    Gaucher disease, the most common sphingolipidosis, is caused by a decreased activity of glucosylceramide beta-glucosidase, resulting in the accumulation of glucosylceramide in macrophage-derived cells known as Gaucher cells. Much of the storage material is thought to originate from the turnover of cell membranes, such as phagocytosed red and white blood cells. In this study, an in vitro model of Gaucher disease was developed by treating the murine macrophage cell line J774 with a specific inhibitor of glucosylceramide beta-glucosidase, conduritol B-epoxide, and feeding red blood cell ghosts, in order to mimic the disease state. It was found in this model system that glucosylceramide beta-glucosidase activity could be reduced to about 11-15% of the normal control level before increased storage of glucosylceramide occurred. This in vitro system allows insight into the correlation between enzyme activity and lipid storage as predicted by the theory of residual enzyme activity that was proposed by Conzelmann and Sandhoff.

  8. Dynamic Modeling and Control of Electromechanical Coupling for Mechanical Elastic Energy Storage System

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2013-01-01

    Full Text Available The structural scheme of mechanical elastic energy storage (MEES system served by permanent magnet synchronous motor (PMSM and bidirectional converters is designed. The aim of the research is to model and control the complex electromechanical system. The mechanical device of the complex system is considered as a node in generalized coordinate system, the terse nonlinear dynamic model of electromechanical coupling for the electromechanical system is constructed through Lagrange-Maxwell energy method, and the detailed deduction of the mathematical model is presented in the paper. The theory of direct feedback linearization (DFL is applied to decouple the nonlinear dynamic model and convert the developed model from nonlinear to linear. The optimal control theory is utilized to accomplish speed tracking control for the linearized system. The simulation results in three different cases show that the proposed nonlinear dynamic model of MEES system is correct; the designed algorithm has a better control performance in contrast with the conventional PI control.

  9. A vertically integrated model with vertical dynamics for CO2 storage

    Science.gov (United States)

    Guo, Bo; Bandilla, Karl W.; Doster, Florian; Keilegavlen, Eirik; Celia, Michael A.

    2014-08-01

    Conventional vertically integrated models for CO2 storage usually adopt a vertical equilibrium (VE) assumption, which states that due to strong buoyancy, CO2 and brine segregate quickly, so that the fluids can be assumed to have essentially hydrostatic pressure distributions in the vertical direction. However, the VE assumption is inappropriate when the time scale of fluid segregation is not small relative to the simulation time. By casting the vertically integrated equations into a multiscale framework, a new vertically integrated model can be developed that relaxes the VE assumption, thereby allowing vertical dynamics to be modeled explicitly. The model maintains much of the computational efficiency of vertical integration while allowing a much wider range of problems to be modeled. Numerical tests of the new model, using injection scenarios with typical parameter sets, show excellent behavior of the new approach for homogeneous geologic formations.

  10. Closeout final report on a demonstration test and evaluation of the Cannon Low-NOx Digester System

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-04-01

    Cannon Boiler Works Inc. has been investigating a system for removing NOx from the exhaust gases of furnaces, gas turbines, chemical reactors, incinerators, and boilers. Computer simulations, bench-scale and pilot plant tests have proved that the system is capable of removing substantially all of the NOx from natural gas fired equipment exhaust streams. Originally designated as the Cannon NOx Digester, it has recently been renamed the Low Temperature Oxidation (LTO) System for NOx and SOx Reduction. The principal elements in the system are a fan, heat exchanger, oxidation chamber, spray chamber acting as a gas/liquid absorber, demister, an ozone generator, liquid oxygen storage or dry air supply system for the ozonator, chemical storage and metering system for the caustic neutralizer, and a data acquisition and control system. Most of the ozone is consumed in converting NOx to N{sub 2}O{sub 5} which hydrates to nitric acid which is then scrubbed out of the gas as it passes through the absorber. CO also reacts with ozone to form CO{sub 2} which is subsequently scrubbed out with NaOH. A demonstration, planned for the Alta Dena Dairy located near Los Angeles and in violation of California`s air quality regulations for natural gas fired boilers, was started, delayed due to boiler modifications, and will be continued shortly with new funding. This paper describes the LTO process and presents results from the initial demonstration.

  11. Property Prediction of Dry Common Carp (Cyprinus Carpio During Storage by Kinetic Model

    Directory of Open Access Journals (Sweden)

    Qian Lu

    2014-12-01

    Full Text Available Common carp (Cyprinus carpio is an important food resource in European and Asian countries. Nowadays, common carp after drying process is appreciated by the transportation agency and food industry because of its low transportation cost. Changes of acid value (AV, total bacterial count (TBC, and peroxide value (PV were reported in this study. We found that the changes of AV, TBC and PV of dry common carp fitted the first order reaction model and the reaction energies of changes of AV, TBC, and PV during storage were 4.56 kJ/mol, 2.21 kJ/mol, and 2.33 kJ/mol, respectively. This study will provide theoretical knowledge to food factories relating with dry fish storage and transportation.

  12. Warehousing in the Global Supply Chain Advanced Models, Tools and Applications for Storage Systems

    CERN Document Server

    2012-01-01

    With increased globalization and offshore sourcing, global supply chain management is becoming an important issue for many businesses as it involves a company's worldwide interests and suppliers rather than simply a local or national orientation. The storage systems significantly affect the level of quality of products, the customer’s service level, and the global logistic cost. The mission of warehousing systems design, control and optimization is to effectively ship products in the right place, at the right time, and in the right quantity (i.e. in any configuration) without any damages or alterations, and minimizing costs. Warehousing in the Global Supply Chain presents and discusses a set of models, tools and real applications, including a few case studies rarely presented with a sufficient detail by other literature, to illustrate the main challenges in warehousing activities. This includes all warehouse operations (from receiving to shipping), problems and issues (e.g. storage allocation, assignment,...

  13. Crane scheduling for a plate storage in a shipyard: Modelling the problem

    DEFF Research Database (Denmark)

    Hansen, Jesper; Kristensen, Torben F.H.

    2003-01-01

    This document is the first in a series of three describing an investigation of possible improvements in methods for handling the storage of steel plates at Odense Steel Shipyard (OSS). Steel ships are constructed by cutting up plates and afterwards welding them together to produce blocks. These b...... a potential reduction in movements by 67% and reduction in time by 39% compared to current practices. This leads to an estimated cost saving by approx. 1.0 mill. dkr. per year. This paper describes the modelling aspects of the investigation.......This document is the first in a series of three describing an investigation of possible improvements in methods for handling the storage of steel plates at Odense Steel Shipyard (OSS). Steel ships are constructed by cutting up plates and afterwards welding them together to produce blocks...

  14. Parallel processing optimization strategy based on MapReduce model in cloud storage environment

    Science.gov (United States)

    Cui, Jianming; Liu, Jiayi; Li, Qiuyan

    2017-05-01

    Currently, a large number of documents in the cloud storage process employed the way of packaging after receiving all the packets. From the local transmitter this stored procedure to the server, packing and unpacking will consume a lot of time, and the transmission efficiency is low as well. A new parallel processing algorithm is proposed to optimize the transmission mode. According to the operation machine graphs model work, using MPI technology parallel execution Mapper and Reducer mechanism. It is good to use MPI technology to implement Mapper and Reducer parallel mechanism. After the simulation experiment of Hadoop cloud computing platform, this algorithm can not only accelerate the file transfer rate, but also shorten the waiting time of the Reducer mechanism. It will break through traditional sequential transmission constraints and reduce the storage coupling to improve the transmission efficiency.

  15. Study of Photovoltaic Energy Storage by Supercapacitors through Both Experimental and Modelling Approaches

    Directory of Open Access Journals (Sweden)

    Pierre-Olivier Logerais

    2013-01-01

    Full Text Available The storage of photovoltaic energy by supercapacitors is studied by using two approaches. An overview on the integration of supercapacitors in solar energy conversion systems is previously provided. First, a realized experimental setup of charge/discharge of supercapacitors fed by a photovoltaic array has been operated with fine data acquisition. The second approach consists in simulating photovoltaic energy storage by supercapacitors with a faithful and accessible model composed of solar irradiance evaluation, equivalent electrical circuit for photovoltaic conversion, and a multibranch circuit for supercapacitor. Both the experimental and calculated results are confronted, and an error of 1% on the stored energy is found with a correction largely within ±10% of the transmission line capacitance according to temperature.

  16. Modeling colliding beams with an element by element representation of the storage ring guide field

    Directory of Open Access Journals (Sweden)

    D. L. Rubin

    2006-01-01

    Full Text Available A detailed model of the Cornell Electron Storage Ring (CESR guide field, including beam-beam interaction computed in the weak-strong regime, is the basis for a multiturn simulation of luminosity. The simulation reproduces the dependence of luminosity on bunch current that is measured in the storage ring, at both high-energy (5.3   GeV/beam and in the wiggler-dominated low energy (CESR-c configuration (1.9   GeV/beam. Dynamics are determined entirely by the physics of propagation through the individual guide field elements with no free parameters. Energy dependence of the compensation of the transverse coupling introduced by the experimental solenoid is found to significantly degrade specific luminosity. The simulation also indicates a strong dependence of limiting beam-beam tune shift parameter on the geometric mean of synchrotron tune and bunch length.

  17. An assessment of aquifer storage recovery using ground water flow models.

    Science.gov (United States)

    Lowry, Christopher S; Anderson, Mary P

    2006-01-01

    Owing to increased demands on ground water accompanied by increased drawdowns, technologies that use recharge options, such as aquifer storage recovery (ASR), are being used to optimize available water resources and reduce adverse effects of pumping. In this paper, three representative ground water flow models were created to assess the impact of hydrogeologic and operational parameters/factors on recovery efficiency of ASR systems. Flow/particle tracking and solute transport models were used to track the movement of water during injection, storage, and recovery. Results from particle tracking models consistently produced higher recovery efficiency than the solute transport models for the parameters/properties examined because the particle tracking models neglected mixing of the injected and ambient water. Mixing between injected and ambient water affected recovery efficiency. Results from this study demonstrate the interactions between hydrogeologic and operational parameters on predictions of recovery efficiency. These interactions are best simulated using coupled numerical ground water flow and transport models that include the effects of mixing of injected water and ambient ground water.

  18. Simulating the Value of Concentrating Solar Power with Thermal Energy Storage in a Production Cost Model

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, P.; Hummon, M.

    2012-11-01

    Concentrating solar power (CSP) deployed with thermal energy storage (TES) provides a dispatchable source of renewable energy. The value of CSP with TES, as with other potential generation resources, needs to be established using traditional utility planning tools. Production cost models, which simulate the operation of grid, are often used to estimate the operational value of different generation mixes. CSP with TES has historically had limited analysis in commercial production simulations. This document describes the implementation of CSP with TES in a commercial production cost model. It also describes the simulation of grid operations with CSP in a test system consisting of two balancing areas located primarily in Colorado.

  19. A logistic model for magnetic energy storage in solar active regions

    Institute of Scientific and Technical Information of China (English)

    Hua-Ning Wang; Yan-Mei Cui; Han He

    2009-01-01

    Previous statistical analyses of a large number of SOHO/MDI full disk longitu-dinal magnetograms provided a result that demonstrated how responses of solar flares to photospheric magnetic properties can be fitted with sigmoid functions. A logistic model reveals that these fitted sigmoid functions might be related to the free energy storage process in solar active regions. Although this suggested model is rather simple, the free energy level of active regions can be estimated and the probability of a solar flare with importance over a threshold can be forecast within a given time window.

  20. Influence of Li-ion Battery Models in the Sizing of Hybrid Storage Systems with Supercapacitors

    DEFF Research Database (Denmark)

    Pinto, Claudio; Barreras, Jorge Varela; de Castro, Ricardo

    2014-01-01

    This paper presents a comparative study of the influence of different aggregated electrical circuit battery models in the sizing process of a hybrid energy storage system (ESS), composed by Li-ion batteries and supercapacitors (SCs). The aim is to find the number of cells required to propel......-order dynamics of the battery. Simulation results demonstrate that the adoption of a more accurate battery model in the sizing of hybrid ESSs prevents over-sizing, leading to a reduction in the number of cells of up to 29%, and a cost decrease of up to 10%....

  1. A Model for Optimizing the Combination of Solar Electricity Generation, Supply Curtailment, Transmission and Storage

    Science.gov (United States)

    Perez, Marc J. R.

    With extraordinary recent growth of the solar photovoltaic industry, it is paramount to address the biggest barrier to its high-penetration across global electrical grids: the inherent variability of the solar resource. This resource variability arises from largely unpredictable meteorological phenomena and from the predictable rotation of the earth around the sun and about its own axis. To achieve very high photovoltaic penetration, the imbalance between the variable supply of sunlight and demand must be alleviated. The research detailed herein consists of the development of a computational model which seeks to optimize the combination of 3 supply-side solutions to solar variability that minimizes the aggregate cost of electricity generated therefrom: Storage (where excess solar generation is stored when it exceeds demand for utilization when it does not meet demand), interconnection (where solar generation is spread across a large geographic area and electrically interconnected to smooth overall regional output) and smart curtailment (where solar capacity is oversized and excess generation is curtailed at key times to minimize the need for storage.). This model leverages a database created in the context of this doctoral work of satellite-derived photovoltaic output spanning 10 years at a daily interval for 64,000 unique geographic points across the globe. Underpinning the model's design and results, the database was used to further the understanding of solar resource variability at timescales greater than 1-day. It is shown that--as at shorter timescales--cloud/weather-induced solar variability decreases with geographic extent and that the geographic extent at which variability is mitigated increases with timescale and is modulated by the prevailing speed of clouds/weather systems. Unpredictable solar variability up to the timescale of 30 days is shown to be mitigated across a geographic extent of only 1500km if that geographic extent is oriented in a north

  2. Altered detrusor gap junction communications induce storage symptoms in bladder inflammation: a mouse cyclophosphamide-induced model of cystitis.

    Science.gov (United States)

    Okinami, Takeshi; Imamura, Masaaki; Nishikawa, Nobuyuki; Negoro, Hiromitsu; Sugino, Yoshio; Yoshimura, Koji; Kanematsu, Akihiro; Hashitani, Hikaru; Ogawa, Osamu

    2014-01-01

    Lower urinary tract symptoms (LUTS) include storage, voiding and post-micturition symptoms, featuring many urological diseases. Storage symptoms are the most frequent among these and associated with overactive bladder and non-bacterial bladder inflammation such as interstitial cystitis/bladder pain syndrome (IC/BPS). Gap junction, a key regulator of hyperactive conditions in the bladder, has been reported to be involved in pathological bladder inflammation. Here we report involvement of gap junction in the etiology of storage symptoms in bladder inflammation. In this study, cyclophosphamide-induced cystitis was adapted as a model of bladder inflammation. Cyclophosphamide-treated mice showed typical storage symptoms including increased urinary frequency and reduced bladder capacity, with concurrent up-regulation of connexin 43 (GJA1), one of the major gap junction proteins in the bladder. In isometric tension study, bladder smooth muscle strips taken from the treated mice showed more pronounced spontaneous contraction than controls, which was attenuated by carbenoxolone, a gap junction inhibitor. In voiding behavior studies, the storage symptoms in the treated mice characterized by frequent voiding were alleviated by 18α-glycyrrhetinic acid, another gap junction inhibitor. These results demonstrate that cyclophosphamide-induced mouse model of cystitis shows clinical storage symptoms related with bladder inflammation and that gap junction in the bladder may be a key molecule of these storage symptoms. Therefore, gap junction in the bladder might be an alternative therapeutic target for storage symptoms in bladder inflammation.

  3. Altered detrusor gap junction communications induce storage symptoms in bladder inflammation: a mouse cyclophosphamide-induced model of cystitis.

    Directory of Open Access Journals (Sweden)

    Takeshi Okinami

    Full Text Available Lower urinary tract symptoms (LUTS include storage, voiding and post-micturition symptoms, featuring many urological diseases. Storage symptoms are the most frequent among these and associated with overactive bladder and non-bacterial bladder inflammation such as interstitial cystitis/bladder pain syndrome (IC/BPS. Gap junction, a key regulator of hyperactive conditions in the bladder, has been reported to be involved in pathological bladder inflammation. Here we report involvement of gap junction in the etiology of storage symptoms in bladder inflammation. In this study, cyclophosphamide-induced cystitis was adapted as a model of bladder inflammation. Cyclophosphamide-treated mice showed typical storage symptoms including increased urinary frequency and reduced bladder capacity, with concurrent up-regulation of connexin 43 (GJA1, one of the major gap junction proteins in the bladder. In isometric tension study, bladder smooth muscle strips taken from the treated mice showed more pronounced spontaneous contraction than controls, which was attenuated by carbenoxolone, a gap junction inhibitor. In voiding behavior studies, the storage symptoms in the treated mice characterized by frequent voiding were alleviated by 18α-glycyrrhetinic acid, another gap junction inhibitor. These results demonstrate that cyclophosphamide-induced mouse model of cystitis shows clinical storage symptoms related with bladder inflammation and that gap junction in the bladder may be a key molecule of these storage symptoms. Therefore, gap junction in the bladder might be an alternative therapeutic target for storage symptoms in bladder inflammation.

  4. Numerical models of mass transfer during ripening and storage of salami

    Directory of Open Access Journals (Sweden)

    Angelo Fabbri

    2013-09-01

    Full Text Available Ripening, in the dry sausages manufacturing process, has an influence over the main physical, chemical and microbiological transformations that take place inside these products and that define the final organoleptic properties of dry sausages. A number of study about the influence of ripening conditions on the main chemical and microbiological characteristics of dry sausages is available today. All these studies indicate that the final quality and safety standards achieved by the sausage manufacturing process can be considered to be strictly dependent from the specific ripening conditions. The water diffusion inside a seasoned sausage is surely an aspect of primary importance with regard to the quality of final product. As a consequence the aim of this research was to develop two parametric numerical models, concerning the moisture diffusion physics, describing salami ripening and storage. Mass transfer equations inside the sausage volume were numerically solved using a finite element technique. A first model describes diffusion phenomena occurring inside the salami and the exchange phenomena involving the surface of the product and the environment. After the ripening, the salami are stored in waterproof packaging, consequently an additional model able to describe also the evaporation and condensation phenomena occurring between the salami surface and the air in the package, was developed. The moisture equilibrium between salami surface and conservation atmosphere is mainly ruled by the temperature changes during storage. Both models allow to analyze the history of the moisture content inside the salami and are parametrised on product size and maturation/storage conditions. The models were experimentally validated, comparing the numerical outputs of the simulations with experimental data, showing a good agreement.

  5. Sustainable Irrigation Allocation Model for Dry and Wet Periods using Reservoir Storage and Inflow

    Science.gov (United States)

    Surianarayanan, S.; Suribabu, C. R.; Ramakrishnan, K.

    2017-07-01

    The dry period agriculture is inevitable both for the farmers for their earning, and for the soil for its fertility by crop-rotation. In tropical countries like INDIA, dry period agriculture becomes difficult because of less (or) no rain fall. Hence a simple water balancing model for irrigation scheduling, using the measure “Volumetric Reliability” is prepared in this paper, with the storage and inflow of a reservoir both for the dry and wet periods. The case-study is done for a reservoir in INDIA with thirty one years of hydrological data(from 1982 to 2012). The objective of this paper is to prepare a simple water balance model taking 10 days periods of demand and supply for ID crop(Irrigated Dry crop, ground nut) with usage of volumetric reliability concept for the periods of deficiency and adoption of less water requirement crops to reduce the water-stress during critical periods of crop growth, and finally arrive at a feasible allocation schedule for the success of agriculture and the yield throughout the year both for wet and dry crops with the available storage on the start of irrigation for a particular year. The reservoir is divided for storages such as full, deficient and critical storages. The starting storage for the dry period from January is used after adequate allocation for wet crops, the quantity for riparian rights and for drinking water, for the sustainability. By the water-balancing, the time-series for thirty one years, it is found that for twenty two years the demand for the ID crops is satisfied with the storage in the reservoir, and in the remaining years of deficient inflows, for three years (1986,1996,2004)the demand is managed by using the safe reliability factor for demand which can nullify the deficit in demand for the whole supply period. But it is genuine to assure that the reduction in the amount of water for each 10 days periods should not exceed the survival limit of the crop. Necessary soil-moisture must be ensured in the crop

  6. Physical multiscale modeling and numerical simulation of electrochemical devices for energy conversion and storage from theory to engineering to practice

    CERN Document Server

    Franco, Alejandro A; Bessler, Wolfgang G

    2015-01-01

    This book reviews the use of innovative physical multiscale modeling methods to deeply understand the electrochemical mechanisms and numerically simulate the structure and properties of electrochemical devices for energy storage and conversion.

  7. Modeling the spatiotemporal organization of velocity storage in the vestibuloocular reflex by optokinetic studies

    Science.gov (United States)

    Raphan, T.; Sturm, D.; Cohen, B. (Principal Investigator)

    1991-01-01

    1. A generalized three-dimensional state space model of visual vestibular interaction was developed. Matrix and dynamical system operators associated with inputs from the semicircular canals, otolith velocity estimator, and the visual system have been incorporated into the model, which focus on their relationship to the velocity storage integrator. 2. A relationship was postulated between the eigenvalues and the direction of the eigenvectors of the system matrix and the orientation of the spatial vertical. It was assumed that the system matrix for a tilted position was a composition of two linear transformations of the system matrix for the upright position. One transformation modifies the eigenvalues of the system matrix, whereas another rotates the eigenvectors of the system matrix. The pitch and roll eigenvectors rotate with the head, whereas the yaw axis eigenvector remains approximately spatially invariant. 3. Based on the three-dimensional model, a computational procedure was formulated to identify the eigenvalues and eigenvectors of the system matrix with the use of a modification of the marquardt algorithm. With the use of data obtained from a monkey, it was shown that the three-dimensional behavior of velocity storage cannot be predicted solely in terms of its time constants, i.e., the inverse of its eigenvalues. With the use of the same eigenvalues the data could either be fit or not fit, depending on the eigenvector directions. Therefore, it is necessary to specify eigenvector directions when characterizing velocity storage in three dimensions. 4. Parameters found with the use of the Marquardt algorithm were incorporated into the model. Diagonal matrices in a head coordinate frame were introduced for coupling the visual system to the integrator and to the direct optokinetic pathway. Simulations of optokinetic nystagmus (OKN) and optokinetic after-nystagmus (OKAN) were run. The model predicted the behavior of yaw and pitch OKN and OKAN when the animal is

  8. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Richard Turton; Chamila Tissera; Emre Tatli; Andy Zimmerman

    2005-12-28

    Selective NOx Recirculation (SNR) involves cooling the engine exhaust gas and then adsorbing the oxides of nitrogen (NOx) from the exhaust stream, followed by the periodic desorption of NOx. By returning the desorbed, concentrated NOx into the engine intake and through the combustion chamber, a percentage of the NOx is decomposed during the combustion process. An initial study of NOx decomposition during lean-burn combustion was concluded in 2004 using a 1993 Cummins L10G 240hp natural gas engine. It was observed that the air/fuel ratio, injected NO (nitric oxide) quantity and engine operating points affected NOx decomposition rates of the engine. Chemical kinetic modeling results were also used to determine optimum NOx decomposition operating points and were published in the 2004 annual report. A NOx decomposition rate of 27% was measured from this engine under lean-burn conditions while the software model predicted between 35-42% NOx decomposition for similar conditions. A later technology 1998 Cummins L10G 280hp natural gas engine was procured with the assistance of Cummins Inc. to replace the previous engine used for 2005 experimental research. The new engine was equipped with an electronic fuel management system with closed-loop control that provided a more stable air/fuel ratio control and improved the repeatability of the tests. The engine was instrumented with an in-cylinder pressure measurement system and electronic controls, and was adapted to operate over a range of air/fuel ratios. The engine was connected to a newly commissioned 300hp alternating current (AC) motoring dynamometer. The second experimental campaign was performed to acquire both stoichiometric and slightly rich (0.97 lambda ratio) burn NOx decomposition rates. Effects of engine load and speed on decomposition were quantified, but Exhaust Gas Recirculation (EGR) was not varied independently. Decomposition rates of up to 92% were demonstrated. Following recommendations at the 2004 ARES peer

  9. Climatic effects on tundra carbon storage inferred from experimental data and a model

    Energy Technology Data Exchange (ETDEWEB)

    McKane, R.B.; Rastetter, E.B.; Shaver, G.R. [Ecosystems Center, Woods Hole, MA (United States)] [and others

    1997-06-01

    A process-based model of ecosystem carbon (C) and nitrogen (N) dynamics, MBL-GEM (Marine Biological Laboratory General Ecosystem Model) was used, to integrate and analyze the results of several experiments that examined the response of arctic tussock tundra to manipulations of CO{sub 2}, temperature, light, and soil nutrients. The experiments manipulated these variables over 3- to 9-yr periods and were intended to simulate anticipated changes in the arctic environment. Our objective was to use the model to extend the analysis of the experimental data so that unmeasured changes in ecosystem C storage and the underlying mechanisms controlling those changes could be estimated and compared. Using an inverse calibration method, we derived a single parameter set for the model that closely simulated the measured responses of tussock tundra to all of the experimental treatments. This parameterization allowed us to infer confidence limits for ecosystem components and processes that were not directly measured in the experiments. Thus, we used the model to estimate changes in ecosystem C storage by inferring key soil processes within the constraints imposed by measured components of the ecosystem C budget. 28 refs., 2 figs., 4 tabs.

  10. Assessment against Experiments of Devolatilization and Char Burnout Models for the Simulation of an Aerodynamically Staged Swirled Low-NOx Pulverized Coal Burner

    Directory of Open Access Journals (Sweden)

    Marco Torresi

    2017-01-01

    Full Text Available In the next few years, even though there will be a continuous growth of renewables and a loss of the share of fossil fuel, energy production will still be strongly dependent on fossil fuels. It is expected that coal will continue to play an important role as a primary energy source in the next few decades due to its lower cost and higher availability with respect to other fossil fuels. However, in order to improve the sustainability of energy production from fossil fuels, in terms of pollutant emissions and energy efficiency, the development of advanced investigation tools is crucial. In particular, computational fluid dynamics (CFD simulations are needed in order to support the design process of low emission burners. Even if in the literature several combustion models can be found, the assessment of their performance against detailed experimental measurements on full-scale pulverized coal burners is lacking. In this paper, the numerical simulation of a full-scale low-NO x , aerodynamically-staged, pulverized coal burner for electric utilities tested in the 48 MW th plant at the Combustion Environment Research Centre (CCA - Centro Combustione e Ambiente of Ansaldo Caldaie S.p.A. in Gioia del Colle (Italy is presented. In particular, this paper is focused on both devolatilization and char burnout models. The parameters of each model have been set according to the coal characteristics without any tuning based on the experimental data. Thanks to a detailed description of the complex geometry of the actual industrial burner and, in particular, of the pulverized coal inlet distribution (considering the entire primary air duct, in order to avoid any unrealistic assumption, a correct selection of both devolatilization and char burnout models and a selection of suited parameters for the NO x modeling, accurate results have been obtained in terms of NO x formation. Since the model parameters have been evaluated a priori, the numerical approach proposed

  11. Hybrid Modeling Optimization of Thermal Efficiency and NOx Emission of Utility Boiler%电站锅炉热效率和NOx排放混合建模与优化

    Institute of Scientific and Technical Information of China (English)

    吕玉坤; 彭鑫; 赵锴

    2011-01-01

    Increasing thermal efficiency of utility boilers and reducing pollutant emission are both important for saving energy and protecting environment. The artificial intelligence method is widely used in boiler combustion optimization. Based on the test data of boiler combustion adjustment in a 300 MW power plant, a model of the boiler combustion system was established by using BP neural network targeting at boiler efficiency and NOx emission. The present model was optimized with the genetic algorithms to improve the training and prediction accuracy. The average prediction error declines from 0.22% to 0.06% for boiler efficiency and from 3.5% to 0.15% for NOx emission concentration. And based on global optimization with genetic algorithm method, the multi-objective optimization was transformed to a single objective optimization with weight coefficients. The results show that the present method can optimize the boiler efficiency and NO~ emission according to practical requirements, and the optimization level depends on each weight coefficient. Thus, the corresponding boiler operation control parameters could be obtained, which can provide guidance for power plant boiler optimal operation.%提高电站锅炉热效率和降低污染物排放对于节约能源和保护环境具有重要意义。人工智能方法在优化锅炉燃烧方面有广泛的应用。该文以某300MW电站锅炉燃烧调整试验数据为基础,采用BP神经网络建立以锅炉效率和NOx排放为目标的锅炉燃烧系统模型,利用遗传算法对模型进行优化,使模型训练精度和预测精度大为提高,锅炉效率平均预测误差由0.22%降至0.06%,NOx排放浓度平均预测误差由3.5%降至0.15%。利用遗传算法进行全局寻优,并用权重系数法将多目标优化转化为单目标优化。结果表明,该方法可根据需要对锅炉效率和NOx排放进行优化,实际中需重点优化锅炉效率或者重点优化NOx排放时

  12. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush

    2003-01-29

    This is the ninth Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. The pilot-scale testing phase of the project has been completed. Calculations are essentially completed for implementing a modeling approach to combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO{sub x} emissions and unburned carbon levels in the furnace exhaust. The REI Configurable Fireside Simulator (CFS) has proven to be an essential component to provide input for these calculations. Niksa Energy Associates expects to deliver their final report in February 2003. Work has continued on the project final report.

  13. A data driven model for the impact of IFT and density variations on CO2 storage capacity in geologic formations

    Science.gov (United States)

    Nomeli, Mohammad A.; Riaz, Amir

    2017-09-01

    Carbon dioxide (CO2) storage in depleted hydrocarbon reservoirs and deep saline aquifers is one of the most promising solutions for decreasing CO2 concentration in the atmosphere. One of the important issues for CO2 storage in subsurface environments is the sealing efficiency of low-permeable cap-rocks overlying potential CO2 storage reservoirs. Though we focus on the effect of IFT in this study as a factor influencing sealing efficiency or storage capacity, other factors such as interfacial interactions, wettability, pore radius and interfacial mass transfer also affect the mobility and storage capacity of CO2 phase in the pore space. The study of the variation of IFT is however important because the pressure needed to penetrate a pore depends on both the pore size and the interfacial tension. Hence small variations in IFT can affect flow across a large population of pores. A novel model is proposed to find the IFT of the ternary systems (CO2/brine-salt) in a range of temperatures (300-373 K), pressures (50-250 bar), and up to 6 molal salinity applicable to CO2 storage in geological formations through a multi-variant non-linear regression of experimental data. The method uses a general empirical model for the quaternary system CO2/brine-salts that can be made to coincide with experimental data for a variety of solutions. We introduce correction parameters into the model, which compensates for uncertainties, and enforce agreement with experimental data. The results for IFT show a strong dependence on temperature, pressure, and salinity. The model has been found to describe the experimental data in the appropriate parameter space with reasonable precision. Finally, we use the new model to evaluate the effects of formation depth on the actual efficiency of CO2 storage. The results indicate that, in the case of CO2 storage in deep subsurface environments as a global-warming mitigation strategy, CO2 storage capacity increases with reservoir depth.

  14. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush

    2002-01-31

    This is the fifth Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. One additional biomass co-firing test burn was conducted during this quarter. In this test (Test 9), up to 20% by weight dry hardwood sawdust and switchgrass was injected through the center of the single-register burner with Jacobs Ranch coal. Jacobs Ranch coal is a low-sulfur Powder River Basin coal ({approx} 0.5% S). The results from Test 9 as well as for Test 8 (conducted late last quarter) are presented in this quarterly report. Significant progress has been made in implementing a modeling approach to combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO{sub x} emissions and unburned carbon levels in the furnace exhaust. Additional results of CFD modeling efforts have been received and preparations are under way for continued pilot-scale combustion experiments with the dual-register burner. Finally, a project review was held at NETL in Pittsburgh, on November 13, 2001.

  15. NOx processing on Solar gas turbines; Turbines, traitement des nox sur les turbines a gaz solar

    Energy Technology Data Exchange (ETDEWEB)

    Chausse, X. [Spie Trindel, 95 - Cergy (France). Service TAG

    1997-12-31

    The Solar Company, in cooperation with Tuma Turbomach, has developed the SoLoNOx combustion system with a dry, lean, premixed compound, allowing for reduced NOx and CO emission levels (respectively 42 ppmv and 50 ppmv at 15 pc O{sub 2}). The combustor size is larger than a conventional combustor in order to maintain combustion efficiency and reduce carbon monoxide levels. Leaner combustion occurs at lower temperatures which produce less nitrogen oxides but require more volume to complete the combustion process. New developments should allow for a further reduction of NOx level at 25 ppmv

  16. Thermodynamic model of a thermal storage air conditioning system with dynamic behavior

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, E; Wen, SY; Shi, L; da Silva, AK

    2013-12-01

    A thermodynamic model was developed to predict transient behavior of a thermal storage system, using phase change materials (PCMs), for a novel electric vehicle climate conditioning application. The main objectives of the paper are to consider the system's dynamic behavior, such as a dynamic air flow rate into the vehicle's cabin, and to characterize the transient heat transfer process between the thermal storage unit and the vehicle's cabin, while still maintaining accurate solution to the complex phase change heat transfer. The system studied consists of a heat transfer fluid circulating between either of the on-board hot and cold thermal storage units, which we refer to as thermal batteries, and a liquid-air heat exchanger that provides heat exchange with the incoming air to the vehicle cabin. Each thermal battery is a shell-and-tube configuration where a heat transfer fluid flows through parallel tubes, which are surrounded by PCM within a larger shell. The system model incorporates computationally inexpensive semianalytic solution to the conjugated laminar forced convection and phase change problem within the battery and accounts for airside heat exchange using the Number of Transfer Units (NTUs) method for the liquid-air heat exchanger. Using this approach, we are able to obtain an accurate solution to the complex heat transfer problem within the battery while also incorporating the impact of the airside heat transfer on the overall system performance. The implemented model was benchmarked against a numerical study for a melting process and against full system experimental data for solidification using paraffin wax as the PCM. Through modeling, we demonstrate the importance of capturing the airside heat exchange impact on system performance, and we investigate system response to dynamic operating conditions, e.g., air recirculation. (C) 2013 Elsevier Ltd. All rights reserved.

  17. Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO2 Storage

    KAUST Repository

    Allen, Rebecca

    2015-04-01

    ABSTRACT Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO2 Storage Rebecca Allen Geological CO2 storage is an engineering feat that has been undertaken around the world for more than two decades, thus accurate modeling of flow and transport behavior is of practical importance. Diffusive and convective transport are relevant processes for buoyancy-driven convection of CO2 into underlying fluid, a scenario that has received the attention of numerous modeling studies. While most studies focus on Darcy-scale modeling of this scenario, relatively little work exists at the pore-scale. In this work, properties evaluated at the pore-scale are used to investigate the transport behavior modeled at the Darcy-scale. We compute permeability and two different forms of tortuosity, namely hydraulic and diffusive. By generating various pore ge- ometries, we find hydraulic and diffusive tortuosity can be quantitatively different in the same pore geometry by up to a factor of ten. As such, we emphasize that these tortuosities should not be used interchangeably. We find pore geometries that are characterized by anisotropic permeability can also exhibit anisotropic diffusive tortuosity. This finding has important implications for buoyancy-driven convection modeling; when representing the geological formation with an anisotropic permeabil- ity, it is more realistic to also account for an anisotropic diffusivity. By implementing a non-dimensional model that includes both a vertically and horizontally orientated 5 Rayleigh number, we interpret our findings according to the combined effect of the anisotropy from permeability and diffusive tortuosity. In particular, we observe the Rayleigh ratio may either dampen or enhance the diffusing front, and our simulation data is used to express the time of convective onset as a function of the Rayleigh ratio. Also, we implement a lattice Boltzmann model for thermal convective flows, which we treat as an analog for

  18. Monitoring and modeling of water storage in karstic area (Larzac, France) with a continuous supraconducting gravimeter

    Science.gov (United States)

    Benjamin, Fores; Cédric, Champollion; Nicolas, Lemoigne; Jean, Chéry

    2014-05-01

    Quantitative knowledge of the groundwater storage and transfer in karstic area is crucial for water resources management and protection. As the karst hydro-geological properties are highly heterogeneous and scale dependent, geophysical observations such as time dependant gravity could be helpful to fill the gap between local (based on boreholes, moisture sensors, …) and global (based on chemistry, river flow, …) studies. Since more than 2 years, the iGrav #002 supraconducting gravimeter is continuously operating in the French GEK observatory(Géodésie de l'Environnement Karstique, OSU OREME, SNO H+) in the Larzac karstic plateau (south of France). The observatory is surrounding more than 250m karstified dolomite, with an unsaturated zone of ~150m thickness. First, the evaluation of the iGrav data (calibration, steps and drift) will be presented. Then a careful analysis of the global, topographic and building effects will be done to evaluate the local water storage only. The gravity data will be integrated with the water level data in nearby boreholes and petrophysical data from core samples. Finally, simple hydrological models will be presented to help the interpretation on the karst groundwater storage and transfer and to merge the whole dataset.

  19. Thermal performance sensitivity studies in support of material modeling for extended storage of used nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Cuta, Judith M.; Suffield, Sarah R.; Fort, James A.; Adkins, Harold E.

    2013-08-15

    The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. • degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds • changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components • changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.

  20. Medical chilling device designed for hypothermic hydration graft storage system: Design, thermohydrodynamic modeling, and preliminary testing

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jung Hwan [Hongik University, Seoul (Korea, Republic of)

    2015-02-15

    Hypothermic hydration graft storage is essential to reduce the metabolic demand of cells in vitro. The alleviated metabolic demands reduce the emergence rate of anaerobic metabolism generating adenosine triphosphate (ATP) energy that creates free radicals. The cessive free radicals can damage cells and tissues due to their highly oxidative power with molecules. Current cooling systems such as a conventional air cooling system and an ice pack system are inappropriate for chilling cell tissues in vitro because of inconvenience in use and inconsistent temperature sustainability caused by large size and progressive melting, respectively. Here, we develop a medical chilling device (MCD) for hypothermic hydration graft storage based on thermo-hydrodynamic modeling and thermal electric cooling technology. Our analysis of obtained hydrodynamic thermal behavior of the MCD revealed that the hypothermic condition of 4 .deg. C was continuously maintained, which increased the survival rates of cells in vitro test by reduced free radicals. The validated performance of the MCD promises future development of an optimal hypothermic hydration graft storage system designed for clinical use.

  1. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush

    2002-04-30

    This is the sixth Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. Two additional biomass co-firing test burns were conducted during this quarter. In the first test (Test 10), up to 20% by weight dry hardwood sawdust and switchgrass was compiled with Galatia coal and injected through the dual-register burner. Galatia coal is a medium-sulfur Illinois Basin coal ({approx}1.0% S). The dual-register burner is a generic low-NO{sub x} burner that incorporates two independent wind boxes. In the second test (Test 11), regular ({approx}70% passing 200 mesh) and finely ground ({approx}90% passing 200 mesh) Pratt Seam coal was injected through the single-register burner to determine if coal grind affects NO{sub x} and unburned carbon emissions. The results of these tests are presented in this quarterly report. Significant progress has been made in implementing a modeling approach to combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO{sub x} emissions and unburned carbon levels in the furnace exhaust. No additional results of CFD modeling have been received as delivery of the Configurable Fireside Simulator is expected during the next quarter. Preparations are under way for continued pilot-scale combustion experiments with the single-register burner and a low-volatility bituminous coal. Some delays have been experienced in the acquisition and processing of biomass. Finally, a project review was held at the offices of Southern Research in Birmingham, on February 27, 2002.

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

    Science.gov (United States)

    Wang, Wei-Qing; Cheng, Hong-Yan; Song, Song-Quan

    2013-01-01

    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.

  3. The effect of lightning NOx production on surface ozone in the continental United States

    Directory of Open Access Journals (Sweden)

    Y. Choi

    2008-03-01

    Full Text Available Lightning NOx emissions calculated using the U.S. National Lightning Detection Network data were found to account for 30% of the total NOx emissions for July–August 2004, a period chosen both for having higher lightning NOx production and high ozone levels, thus maximizing the likelihood that such emissions could impact peak ozone levels. Including such emissions led to modest, but sometimes significant increases in simulated surface ozone when using the Community Multi-scale Air Quality Model (CMAQ. Three model simulations were performed, two with the addition of lightning NOx emissions, and one without. Domain-wide daily maximum 8-h ozone changes due to lightning NOx were less than 2 ppbv in 71% of the cases with a maximum of 10-ppbv; whereas the difference in 1-h ozone was less than 2 ppbv in 77% of the cases with a maximum of 6 ppbv. Daily maximum 1-h and 8-h ozone for grids containing O3 monitoring stations changed slightly, with more than 43% of the cases differing less than 2 ppbv. The greatest differences were 42-ppbv for both 1-h and 8-h O3, though these tended to be on days of lower ozone. Lightning impacts on the season-wide maximum 1-h and 8-h averaged ozone decreased starting from the 1st to 4th highest values (an average of 4th highest, 8-h values is used for attainment demonstration in the U.S.. Background ozone values from the y-intercept of O3 versus NOz curve were 42.2 and 43.9 ppbv for simulations without and with lightning emissions, respectively. Results from both simulations with lightning NOx suggest that while North American lightning production of NOx can lead to significant local impacts on a few occasions, they will have a relatively small impact on typical maximum levels and determination of Policy Relevant Background levels.

  4. 40 CFR 86.1862-04 - Maintenance of records and submittal of information relevant to compliance with fleet average NOX...

    Science.gov (United States)

    2010-07-01

    ... each LDV/T or MDPV subject to this subpart: (i) Model year; (ii) Applicable fleet average NOX standard... which the LDV/T or MDPV is certified; and (vii) Information on the point of first sale, including the...

  5. Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Saxon, Aron R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Keyser, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lundstrom, Blake R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cao, Ziwei [SunPower Corporation; Roc, Albert [SunPower Corporation

    2017-09-06

    Lithium-ion (Li-ion) batteries are being deployed on the electrical grid for a variety of purposes, such as to smooth fluctuations in solar renewable power generation. The lifetime of these batteries will vary depending on their thermal environment and how they are charged and discharged. To optimal utilization of a battery over its lifetime requires characterization of its performance degradation under different storage and cycling conditions. Aging tests were conducted on commercial graphite/nickel-manganese-cobalt (NMC) Li-ion cells. A general lifetime prognostic model framework is applied to model changes in capacity and resistance as the battery degrades. Across 9 aging test conditions from 0oC to 55oC, the model predicts capacity fade with 1.4% RMS error and resistance growth with 15% RMS error. The model, recast in state variable form with 8 states representing separate fade mechanisms, is used to extrapolate lifetime for example applications of the energy storage system integrated with renewable photovoltaic (PV) power generation.

  6. Evaluation of the Fluid Model Approach for the Sizing of Energy Storage in Wave-Wind Energy Systems

    Directory of Open Access Journals (Sweden)

    José A. Domínguez-Navarro

    2016-03-01

    Full Text Available The application of energy storage in offshore renewable generation systems allows managing the intrinsic uncertainty of the resources and improving the utilization factor of the electrical network. Optimal storage design algorithms generally have to evaluate the behavior of the whole system thousands times before converging to the optimal solution and the reliability of the results obviously depends on the quality of input data. On the other hand, the utilization of simplified storage models in the design stage can reduce the simulation time drastically, while still providing useful information. The goal of this paper is to evaluate the applicability of a methodology for sizing the energy storage system in a hybrid wind and wave farm, which is based on fluid models. The description and performance of this modeling approach will be introduced and compared to standard design procedures based on extensive simulations. Advantages and limitations of each approach will be underlined and the impact of input data quality will be discussed.

  7. A storage model approach to the assessment of snow depth trends

    Science.gov (United States)

    Woody, Jonathan; Lund, Robert; Grundstein, Andrew J.; Mote, Thomas L.

    2009-10-01

    This paper introduces a stochastic storage model capable of assessing trends in daily snow depth series. The model allows for seasonal features, which permits the analysis of daily data. Breakpoint times, which occur when the observing station changes location or instrumentation, are shown to greatly influence estimated trend margins and are accounted for in this analysis. The model is fitted by numerically minimizing a sum of squares of daily prediction errors. Standard errors for the model parameters, useful in making trend inferences, are presented. The methods are illustrated in the analysis of a century of daily snow depth observations from Napoleon, North Dakota. The results here show that snow depths are significantly declining at Napoleon, with spring ablation occurring earlier, and that breakpoint features are very influential in deriving realistic trend estimates.

  8. DEVELOPMENT OF A NOVEL RADIATIVELY/CONDUCTIVELY STABILIZED BURNER FOR SIGNIFICANT REDUCTION OF NOx EMISSIONS AND FOR ADVANCING THE MODELING AND UNDERSTANDING OF PULVERIZED COAL COMBUSTION AND EMISSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Noam Lior; Stuart W. Churchill

    2003-10-01

    The primary objective of the proposed study was the study and analysis of, and design recommendations for, a novel radiatively-conductively stabilized combustion (RCSC) process for pulverized coal, which, based on our prior studies with both fluid fuels and pulverized coal, holds a high promise to reduce NO{sub x} production significantly. We have primarily engaged in continuing and improving our process modeling and analysis, obtained a large amount of quantitative information about the effects of the major parameters on NO{sub x} production, conducted an extensive exergy analysis of the process, evaluated the practicalities of employing the Radiatively-Conductively Stabilized Combustor (RCSC) to large power and heat plants, and improved the experimental facility. Prior experimental work has proven the feasibility of the combustor, but slagging during coal combustion was observed and should be dealt with. The primary outcomes and conclusions from the study are: (1) we developed a model and computer program that represents the pulverized coal combustion in the RCSC, (2) the model predicts that NO{sub x} emissions can be reduced by a number of methods, detailed in the report. (3) the exergy analysis points out at least a couple of possible ways to improve the exergetic efficiency in this combustor: increasing the effectiveness of thermal feedback, and adjusting the combustor mixture exit location, (4) because of the low coal flow rates necessitated in this study to obtain complete combustion in the burner, the size of a burner operating under the considered conditions would have to be up to an order of magnitude, larger than comparable commercial burners, but different flow configurations of the RCSC can yield higher feed rates and smaller dimensions, and should be investigated. Related to this contract, eleven papers were published in journals and conference proceedings, and ten invited presentations were given at university and research institutions, as well as at

  9. DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO-FIRING BIOMASS WITH COAL

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Felix; P. Vann Bush

    2002-07-01

    This is the seventh Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. Two additional biomass co-firing test burns were conducted during this quarter. In the first test (Test 12), up to 20% by weight dry hardwood sawdust and switchgrass was comilled with Galatia coal and injected through the single-register burner. Liquid ammonia was intermittently added to the primary air stream to increase fuel-bound nitrogen and simulate cofiring with chicken litter. Galatia coal is a medium-sulfur ({approx} 1.2% S), high chlorine ({approx}0.5%) Illinois Basin coal. In the second test (Test 13), up to 20% by weight dry hardwood sawdust and switchgrass was comilled with Jim Walters No.7 mine coal and injected through the single-register burner. Jim Walters No.7 coal is a low-volatility, low-sulfur ({approx} 0.7% S) Eastern bituminous coal. The results of these tests are presented in this quarterly report. Progress has continued to be made in implementing a modeling approach to combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO{sub x} emissions and unburned carbon levels in the furnace exhaust. The Configurable Fireside Simulator has been delivered from REI, Inc. and is being tested with exiting CFD solutions. Preparations are under way for a final pilot-scale combustion experiment using the single-register burner fired with comilled mixtures of Jim Walters No.7 low-volatility bituminous coal and switchgrass. Because of the delayed delivery of the Configurable Fireside Simulator, it is planned to ask for a no-cost time extension for the project until the end of this calendar year. Finally, a paper describing this project that included preliminary results from the first four cofiring tests was presented at the 12th European

  10. Modeling and Optimal Operation of Distributed Battery Storage in Low Voltage Grids

    OpenAIRE

    Fortenbacher, Philipp; Mathieu, Johanna L.; Andersson, Göran

    2016-01-01

    Due to high power in-feed from photovoltaics, it can be expected that more battery systems will be installed in the distribution grid in near future to mitigate voltage violations and thermal line and transformer overloading. In this paper, we present a two-stage centralized model predictive control scheme for distributed battery storage that consists of a scheduling entity and a real-time control entity. To guarantee secure grid operation, we solve a robust multi-period optimal power flow (O...

  11. NOx production and rainout from Chicxulub impact ejecta reentry

    Science.gov (United States)

    Parkos, Devon; Alexeenko, Alina; Kulakhmetov, Marat; Johnson, Brandon C.; Melosh, H. Jay

    2015-12-01

    The Chicxulub impact 66.0 Ma ago initiated the second biggest extinction in the Phanerozoic Eon. The cause of the concurrent oceanic nitrogen isotopic anomaly, however, remains elusive. The Chicxulub impactor struck the Yucatán peninsula, ejecting 2 × 1015 kg of molten and vaporized rock that reentered globally as approximately 1023 microscopic spherules. Here we report that modern techniques indicate that this ejecta generates 1.5 × 1014 moles of NOx, which is enough to cause the observed nitrogen enrichment of the basal layer. Additionally, reentry-based NO production would explain the anomalously heavy isotopic composition of the observed nitrogen. We include N, O, N2, O2, and NO species in simulations of nonequilibrium chemically reacting flow around a reentering spherule. We then determine the net production of NO from all the spherules and use turbulence models to determine how quickly this yield diffuses through the atmosphere. Upon reaching the stratosphere and troposphere, cloud moisture absorbs the NOx and forms nitric acid. We model this process and determine the acidity of the resulting precipitation, which peaks about 1 year after the impact. The precipitation ultimately reaches the upper ocean, where we assume that the well-mixed surface layer is 100 m deep. We then model the naturally occurring carbonate/bicarbonate buffer and determine the net pH. We find that insufficient NOx reaches the ocean to directly cause the observed end-Cretaceous oceanic extinction via acidification and buffer removal. However, the resulting nitrates are sufficient to explain the concurrent nitrogen isotopic anomaly and facilitate an end-Cretaceous algae bloom.

  12. Fleet average NOx emission performance of 2007 model year light-duty vehicles, light-duty trucks and medium-duty passenger vehicles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-09-15

    This report summarized the regulatory requirements related to nitrous oxide (NO{sub x}) fleet averaging for light-duty vehicles, light-duty trucks, and medium-duty passenger vehicles under the On-Road Vehicle and Engine Emission Regulations. The regulations introduced more stringent national emission standards for on-road vehicles and engines and include technical standards that establish maximum limits on vehicle exhaust emissions. The fleet average NO{sub x} emission performance of individual companies and the overall Canadian fleet for 2007 was summarized, and the effectiveness of the Canadian fleet average NO{sub x} emission program was evaluated in relation to its environmental performance objectives. A total of 22 companies submitted reports for 294 test groups comprising 1,599,051 vehicles of the 2007 model year. The average NO{sub x} value for the entire LDV/LLDT fleet was 0.06897630 grams per mile. The average value for the HLDT/MDPV fleet was 0.160668 grams per mile. NO{sub x} values for both overall fleets remained better than the corresponding fleet average NO{sub x} standards, and were consistent with the environmental performance objectives of the regulations. 9 tabs., 3 figs.

  13. Solid State Electrochemical DeNOx

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2010-01-01

    The literature on direct electrochemical reduction of NOx in a solid state cell has been reviewed. It is shown that that the reduction of nitric oxide either occurs on the electrode or on the electrolyte if F-centers are formed. It is also shown that some oxide based electrodes has a high apparent...

  14. A Split-Path Schema-Based RFID Data Storage Model in Supply Chain Management

    Directory of Open Access Journals (Sweden)

    Jianfeng Zhang

    2013-05-01

    Full Text Available In modern supply chain management systems, Radio Frequency IDentification (RFID technology has become an indispensable sensor technology and massive RFID data sets are expected to become commonplace. More and more space and time are needed to store and process such huge amounts of RFID data, and there is an increasing realization that the existing approaches cannot satisfy the requirements of RFID data management. In this paper, we present a split-path schema-based RFID data storage model. With a data separation mechanism, the massive RFID data produced in supply chain management systems can be stored and processed more efficiently. Then a tree structure-based path splitting approach is proposed to intelligently and automatically split the movement paths of products . Furthermore, based on the proposed new storage model, we design the relational schema to store the path information and time information of tags, and some typical query templates and SQL statements are defined. Finally, we conduct various experiments to measure the effect and performance of our model and demonstrate that it performs significantly better than the baseline approach in both the data expression and path-oriented RFID data query performance.

  15. Assessing Drought Impacts on Water Storage using GRACE Satellites and Regional Groundwater Modeling in the Central Valley of California

    Science.gov (United States)

    Scanlon, B. R.; Zhang, Z.; Save, H.; Faunt, C. C.; Dettinger, M. D.

    2015-12-01

    Increasing concerns about drought impacts on water resources in California underscores the need to better understand effects of drought on water storage and coping strategies. Here we use a new GRACE mascons solution with high spatial resolution (1 degree) developed at the Univ. of Texas Center for Space Research (CSR) and output from the most recent regional groundwater model developed by the U.S. Geological Survey to evaluate changes in water storage in response to recent droughts. We also extend the analysis of drought impacts on water storage back to the 1980s using modeling and monitoring data. The drought has been intensifying since 2012 with almost 50% of the state and 100% of the Central Valley under exceptional drought in 2015. Total water storage from GRACE data declined sharply during the current drought, similar to the rate of depletion during the previous drought in 2007 - 2009. However, only 45% average recovery between the two droughts results in a much greater cumulative impact of both droughts. The CSR GRACE Mascons data offer unprecedented spatial resolution with no leakage to the oceans and no requirement for signal restoration. Snow and reservoir storage declines contribute to the total water storage depletion estimated by GRACE with the residuals attributed to groundwater storage. Rates of groundwater storage depletion are consistent with the results of regional groundwater modeling in the Central Valley. Traditional approaches to coping with these climate extremes has focused on surface water reservoir storage; however, increasing conjunctive use of surface water and groundwater and storing excess water from wet periods in depleted aquifers is increasing in the Central Valley.

  16. Ecosystem carbon storage capacity as affected by disturbance regimes: A general theoretical model

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Ensheng [University of Oklahoma, Norman; Luo, Yiqi [University of Oklahoma; Wang, Weile [NASA Ames Research Center; Wang, Han [University of Oklahoma, Norman; Hayes, Daniel J [ORNL; McGuire, A. David [University of Alaska; Hastings, Alan [University of California, Davis; Schimel, David [NEON Inc.

    2012-01-01

    Disturbances have been recognized as a key factor shaping terrestrial ecosystem states and dynamics. A general model that quantitatively describes the relationship between carbon storage and disturbance regime is critical for better understanding large scale terrestrial ecosystem carbon dynamics. We developed a model (REGIME) to quantify ecosystem carbon storage capacities (E[x]) under varying disturbance regimes with an analytical solution E[x] = U {center_dot} {tau}{sub E} {center_dot} {lambda}{lambda} + s {tau} 1, where U is ecosystem carbon influx, {tau}{sub E} is ecosystem carbon residence time, and {tau}{sub 1} is the residence time of the carbon pool affected by disturbances (biomass pool in this study). The disturbance regime is characterized by the mean disturbance interval ({lambda}) and the mean disturbance severity (s). It is a Michaelis-Menten-type equation illustrating the saturation of carbon content with mean disturbance interval. This model analytically integrates the deterministic ecosystem carbon processes with stochastic disturbance events to reveal a general pattern of terrestrial carbon dynamics at large scales. The model allows us to get a sense of the sensitivity of ecosystems to future environmental changes just by a few calculations. According to the REGIME model, for example, approximately 1.8 Pg C will be lost in the high-latitude regions of North America (>45{sup o} N) if fire disturbance intensity increases around 5.7 time the current intensity to the end of the twenty-first century, which will require around 12% increases in net primary productivity (NPP) to maintain stable carbon stocks. If the residence time decreased 10% at the same time additional 12.5% increases in NPP are required to keep current C stocks. The REGIME model also lays the foundation for analytically modeling the interactions between deterministic biogeochemical processes and stochastic disturbance events.

  17. Cyclone Boiler Field Testing of Advanced Layered NOx Control Technology in Sioux Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Marc A. Cremer; Bradley R. Adams

    2006-06-30

    A four week testing program was completed during this project to assess the ability of the combination of deep staging, Rich Reagent Injection (RRI), and Selective Non-Catalytic Reduction (SNCR) to reduce NOx emissions below 0.15 lb/MBtu in a cyclone fired boiler. The host site for the tests was AmerenUE's Sioux Unit 1, a 500 MW cyclone fired boiler located near St. Louis, MO. Reaction Engineering International (REI) led the project team including AmerenUE, FuelTech Inc., and the Electric Power Research Institute (EPRI). This layered approach to NOx reduction is termed the Advanced Layered Technology Approach (ALTA). Installed RRI and SNCR port locations were guided by computational fluid dynamics (CFD) based modeling conducted by REI. During the parametric testing, NOx emissions of 0.12 lb/MBtu were achieved consistently from overfire air (OFA)-only baseline NOx emissions of 0.25 lb/MBtu or less, when firing the typical 80/20 fuel blend of Powder River Basin (PRB) and Illinois No.6 coals. From OFA-only baseline levels of 0.20 lb/MBtu, NOx emissions of 0.12 lb/MBtu were also achieved, but at significantly reduced urea flow rates. Under the deeply staged conditions that were tested, RRI performance was observed to degrade as higher blends of Illinois No.6 were used. NOx emissions achieved with ALTA while firing a 60/40 blend were approximately 0.15 lb/MBtu. NOx emissions while firing 100% Illinois No.6 were approximately 0.165 lb/MBtu. Based on the performance results of these tests, economics analyses of the application of ALTA to a nominal 500 MW cyclone unit show that the levelized cost to achieve 0.15 lb/MBtu is well below 75% of the cost of a state of the art SCR.

  18. Air quality benefits of universal particle filter and NOx controls on diesel trucks

    Science.gov (United States)

    Tao, L.; Mcdonald, B. C.; Harley, R.

    2015-12-01

    Heavy-duty diesel trucks are a major source of black carbon/particulate matter and nitrogen oxide emissions on urban and regional scales. These emissions are relevant to both air quality and climate change. Since 2010 in the US, new engines are required to be equipped with emission control systems that greatly reduce both PM and NOx emissions, by ~98% relative to 1988 levels. To reduce emissions from the legacy fleet of older trucks that still remain on the road, regulations have been adopted in Califonia to accelerate the replacement of older trucks and thereby reduce associated emissions of PM and NOx. Use of diesel particle filters will be widespread by 2016, and universal use of catalytic converters for NOx control is required by 2023. We assess the air quality consequences of this clean-up effort in Southern California, using the Community Multiscale Air Quality model (CMAQ), and comparing three scenarios: historical (2005), present day (2016), and future year (2023). Emissions from the motor vehicle sector are mapped at high spatial resolution based on traffic count and fuel sales data. NOx emissions from diesel engines in 2023 are expected to decrease by ~80% compared to 2005, while the fraction of NOx emitted as NO2 is expected to increase from 5 to 18%. Air quality model simulations will be analyzed to quantify changes in NO2, black carbon, particulate matter, and ozone, both basin-wide and near hot spots such as ports and major highways.

  19. Urban eddy covariance measurements reveal significant missing NOx emissions in Central Europe.

    Science.gov (United States)

    Karl, T; Graus, M; Striednig, M; Lamprecht, C; Hammerle, A; Wohlfahrt, G; Held, A; von der Heyden, L; Deventer, M J; Krismer, A; Haun, C; Feichter, R; Lee, J

    2017-05-30

    Nitrogen oxide (NOx) pollution is emerging as a primary environmental concern across Europe. While some large European metropolitan areas are already in breach of EU safety limits for NO2, this phenomenon does not seem to be only restricted to large industrialized areas anymore. Many smaller scale populated agglomerations including their surrounding rural areas are seeing frequent NO2 concentration violations. The question of a quantitative understanding of different NOx emission sources is therefore of immanent relevance for climate and air chemistry models as well as air pollution management and health. Here we report simultaneous eddy covariance flux measurements of NOx, CO2, CO and non methane volatile organic compound tracers in a city that might be considered representative for Central Europe and the greater Alpine region. Our data show that NOx fluxes are largely at variance with modelled emission projections, suggesting an appreciable underestimation of the traffic related atmospheric NOx input in Europe, comparable to the weekend-weekday effect, which locally changes ozone production rates by 40%.

  20. Combining support vector regression and ant colony optimization to reduce NOx emissions in coal-fired utility boilers

    Energy Technology Data Exchange (ETDEWEB)

    Ligang Zheng; Hao Zhou; Chunlin Wang; Kefa Cen [Zhejiang University, Hangzhou (China). State Key Laboratory of Clean Energy Utilization

    2008-03-15

    Combustion optimization has recently demonstrated its potential to reduce NOx emissions in high capacity coal-fired utility boilers. In the present study, support vector regression (SVR), as well as artificial neural networks (ANN), was proposed to model the relationship between NOx emissions and operating parameters of a 300 MW coal-fired utility boiler. The predicted NOx emissions from the SVR model, by comparing with that of the ANN-based model, showed better agreement with the values obtained in the experimental tests on this boiler operated at different loads and various other operating parameters. The mean modeling error and the correlation factor were 1.58% and 0.94, respectively. Then, the combination of the SVR model with ant colony optimization (ACO) to reduce NOx emissions was presented in detail. The experimental results showed that the proposed approach can effectively reduce NOx emissions from the coal-fired utility boiler by about 18.69% (65 ppm). A time period of less than 6 min was required for NOx emissions modeling, and 2 min was required for a run of optimization under a PC system. The computing times are suitable for the online application of the proposed method to actual power plants. 37 refs., 8 figs., 3 tabs.

  1. Multi-period MINLP model for investigating long-time thermal storages in DH network applied to Suwon, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Tveit, T.M.; Fogelholm, C.J. (Helsinki Univ. of Technology, Dept. of Energy Technology, P.O.Box 4400, FI-02015 TKK (Finland)); Sangsu, K. (Korea District Heating Corp., R and D Dept., 186 Bundang-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-908 (Korea))

    2008-09-15

    In this paper a multi-period MINLP model for optimising operation and structural changes to CHP plants in district heating networks with long-term thermal storage is applied to an existing district heating network. The best result found shows an annual profit of approximately 22.9 million USD. The best solution found without the thermal storage shows an annual profit of 18.1 million USD. This gives an estimate of the value of the long-term thermal storage of 4.8 million USD/a

  2. Seasonal Thermal-Energy Storage: A Critical Review on BTES Systems, Modeling, and System Design for Higher System Efficiency

    Directory of Open Access Journals (Sweden)

    Michael Lanahan

    2017-05-01

    Full Text Available Buildings consume approximately ¾ of the total electricity generated in the United States, contributing significantly to fossil fuel emissions. Sustainable and renewable energy production can reduce fossil fuel use, but necessitates storage for energy reliability in order to compensate for the intermittency of renewable energy generation. Energy storage is critical for success in developing a sustainable energy grid because it facilitates higher renewable energy penetration by mitigating the gap between energy generation and demand. This review analyzes recent case studies—numerical and field experiments—seen by borehole thermal energy storage (BTES in space heating and domestic hot water capacities, coupled with solar thermal energy. System design, model development, and working principle(s are the primary focus of this analysis. A synopsis of the current efforts to effectively model BTES is presented as well. The literature review reveals that: (1 energy storage is most effective when diurnal and seasonal storage are used in conjunction; (2 no established link exists between BTES computational fluid dynamics (CFD models integrated with whole building energy analysis tools, rather than parameter-fit component models; (3 BTES has less geographical limitations than Aquifer Thermal Energy Storage (ATES and lower installation cost scale than hot water tanks and (4 BTES is more often used for heating than for cooling applications.

  3. Decomposition by ectomycorrhizal fungi alters soil carbon storage in a simulation model

    DEFF Research Database (Denmark)

    Moore, J. A. M.; Jiang, J.; Post, W. M.

    2015-01-01

    that ectomycorrhizal fungi can also be active decomposers when plant carbon allocation to fungi is low. Here, we reviewed the literature on ectomycorrhizal decomposition and we developed a simulation model of the plant-mycorrhizae interaction where a reduction in plant productivity stimulates ectomycorrhizal fungi...... to decompose soil organic matter. Our review highlights evidence demonstrating the potential for ectomycorrhizal fungi to decompose soil organic matter. Our model output suggests that ectomycorrhizal activity accounts for a portion of carbon decomposed in soil, but this portion varied with plant productivity...... and the mycorrhizal carbon uptake strategy simulated. Lower organic matter inputs to soil were largely responsible for reduced soil carbon storage. Using mathematical theory, we demonstrated that biotic interactions affect predictions of ecosystem functions. Specifically, we developed a simple function to model...

  4. NOX, NOX who is there?, The contribution of NADPH Oxidase to beta cell dysfunction.

    Directory of Open Access Journals (Sweden)

    David eTaylor-Fishwick

    2013-04-01

    Full Text Available Predictions of diabetes prevalence over the next decades warrant the aggressive discovery of new approaches to stop or reverse loss of functional beta cell mass. Beta cells are recognized to have a relatively high sensitivity to reactive oxygen species (ROS and become dysfunctional under oxidative stress conditions. New discoveries have identified NADPH oxidases in beta cells as contributors to elevated cellular ROS. Reviewed are recent reports that evidence a role for NADPH oxidase-1 (NOX-1 in beta cell dysfunction. NOX-1 is stimulated by inflammatory cytokines that are elevated in diabetes. First, regulation of cytokine-stimulated NOX-1 expression has been linked to inflammatory lipid mediators derived from 12-lipoxyganase activity. For the first time in beta cells these data integrate distinct pathways associated with beta cell dysfunction. Second, regulation of NOX-1 in beta cells involves feed-forward control linked to elevated ROS and Src-kinase activation. This potentially results in unbridled ROS generation and identifies candidate targets for pharmacologic intervention. Third, consideration is provided of new, first-in-class, selective inhibitors of NOX-1. These compounds could have an important role in assessing a disruption of NOX-1/ROS signaling as a new approach to preserve and protect beta cell mass in diabetes.

  5. HEAT STORAGE SYSTEM WITH PHASE CHANGE MATERIALS IN COGENERATION UNITS: STUDY OF PRELIMINARY MODEL

    Directory of Open Access Journals (Sweden)

    Claudio Caprara

    2008-12-01

    Full Text Available The continuous increase in the mechanization of farm activities, the rise in fuel prices and the environmental aspects concerning gas emissions are the main driving forces behind efforts toward more effective use of renewable energy sources and cogeneration systems even in agricultural and cattle farms. Nevertheless these systems are still not very suitable for this purpose because of their little flexibility in following the changing energy demand as opposed to the extremely various farm load curves, both in daytime and during the year. In heat recovery systems, the available thermal energy supply is always linked to power production, thus it does not usually coincide in time with the heat demand. Hence some form of thermal energy storage (TES is necessary in order to reach the most effective utilization of the energy source. This study deals with the modelling of a packed bed latent heat TES unit, integrating a cogeneration system made up of a reciprocating engine. The TES unit contains phase change materials (PCMs filled in spherical capsules, which are packed in an insulated cylindrical storage tank. Water is used as heat transfer fluid (HTF to transfer heat from the tank to the final uses, and exhausts from the engine are used as thermal source. PCMs are considered especially for their large heat storage capacity and their isothermal behaviour during the phase change processes. Despite their high energy storage density, most of them have an unacceptably low thermal conductivity, hence PCMs encapsulation technique is adopted in order to improve heat transfer. The special modular configuration of heat exchange tubes and the possibility of changing water flow through them allow to obtain the right amount of thermal energy from the tank, according to the hourly demand of the day. The model permits to choose the electrical load of the engine, the dimensions of the tank and the spheres, thickness and diameter of heat exchanger and the nature of

  6. An Optimization Scheduling Model for Wind Power and Thermal Power with Energy Storage System considering Carbon Emission Trading

    Directory of Open Access Journals (Sweden)

    Huan-huan Li

    2015-01-01

    Full Text Available Wind power has the characteristics of randomness and intermittence, which influences power system safety and stable operation. To alleviate the effect of wind power grid connection and improve power system’s wind power consumptive capability, this paper took emission trading and energy storage system into consideration and built an optimization model for thermal-wind power system and energy storage systems collaborative scheduling. A simulation based on 10 thermal units and wind farms with 2800 MW installed capacity verified the correctness of the models put forward by this paper. According to the simulation results, the introduction of carbon emission trading can improve wind power consumptive capability and cut down the average coal consumption per unit of power. The introduction of energy storage system can smooth wind power output curve and suppress power fluctuations. The optimization effects achieve the best when both of carbon emission trading and energy storage system work at the same time.

  7. Thermocline thermal storage systems for concentrated solar power plants: One-dimensional numerical model and comparative analysis

    DEFF Research Database (Denmark)

    Modi, Anish; Pérez-Segarra, Carlos David

    2014-01-01

    Concentrated solar power plants have attracted increasing interest from researchers and governments all over the world in recent years. An important part of these plants is the storage system which improves dispatchability and makes the plant more reliable. In this paper, a one......-dimensional transient mathematical model for a single-tank thermocline thermal energy storage system is presented. The model used temperature dependent correlations to obtain the thermophysical properties for the heat transfer fluid and considered heat loss through the tank wall. The effect of variation in important...... required to attain equilibrium conditions. These aspects directly influence the discharge capacity and discharge power of the storage system, and therefore play an essential role in understanding the start-up characteristics of the system and provide an insight regarding the availability of storage when...

  8. Heterogeneity of intracellular polymer storage states in enhanced biological phosphorus removal (EBPR)--observation and modeling.

    Science.gov (United States)

    Bucci, Vanni; Majed, Nehreen; Hellweger, Ferdi L; Gu, April Z

    2012-03-20

    A number of agent-based models (ABMs) for biological wastewater treatment processes have been developed, but their skill in predicting heterogeneity of intracellular storage states has not been tested against observations due to the lack of analytical methods for measuring single-cell intracellular properties. Further, several mechanisms can produce and maintain heterogeneity (e.g., different histories, uneven division) and their relative importance has not been explored. This article presents an ABM for the enhanced biological phosphorus removal (EBPR) treatment process that resolves heterogeneity in three intracellular polymer storage compounds (i.e., polyphosphate, polyhydroxybutyrate, and glycogen) in three functional microbial populations (i.e., polyphosphate-accumulating, glycogen-accumulating, and ordinary heterotrophic organisms). Model predicted distributions were compared to those based on single-cell estimates obtained using a Raman microscopy method for a laboratory-scale sequencing batch reactor (SBR) system. The model can reproduce many features of the observed heterogeneity. Two methods for introducing heterogeneity were evaluated. First, biological variability in individual cell behavior was simulated by randomizing model parameters (e.g., maximum acetate uptake rate) at division. This method produced the best fit to the data. An optimization algorithm was used to determine the best variability (i.e., coefficient of variance) for each parameter, which suggests large variability in acetate uptake. Second, biological variability in individual cell states was simulated by randomizing state variables (e.g., internal nutrient) at division, which was not able to maintain heterogeneity because the memory in the internal states is too short. These results demonstrate the ability of ABM to predict heterogeneity and provide insights into the factors that contribute to it. Comparison of the ABM with an equivalent population-level model illustrates the effect

  9. Frozen Characteristics of NO_x and Their Related Compositions in Combustion Gas

    Institute of Scientific and Technical Information of China (English)

    苏适; 蔡崧; 徐益谦

    1994-01-01

    In order to study the produce and reduce characteristics of the NOx in the process of fuel combustion and combustion gas denitrogenation, the frozen characteristics of the NOx and their related components of uniform gases at high temperature of 1400 - 2600 K in a quenching rate of 0.2×108 -0.4×108 K/s are studied. The effects of cooling rate on the results of analysis of NO and NO2 in gases sampled by sampling probe are discussed. The mathematical models and chemical kinetic models which express the relaxation process of gas compositions in nonequilibrium condition of quenching process are constructed.

  10. Evaluation of Water Injection Effect on NO(x) Formation for a Staged Gas Turbine Combustor

    Science.gov (United States)

    Fan, L.; Yang, S. L.; Kundu, K. P.

    1996-01-01

    NO(x) emission control by water injection on a staged turbine combustor (STC) was modeled using the KIVA-2 code with modification. Water is injected into the rich-burn combustion zone of the combustor by a single nozzle. Parametric study for different water injection patterns was performed. Results show NO(x) emission will decrease after water being injected. Water nozzle location also has significant effect for NO formation and fuel ignition. The chemical kinetic model is also sensitive to the excess water. Through this study, a better understanding of the physics and chemical kinetics is obtained, this will enhance the STC design process.

  11. NOx CONTROL OPTIONS AND INTEGRATION FOR US COAL FIRED BOILERS

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Marc Cremer; Kevin Davis; Connie Senior; Bob Hurt; Eric Eddings; Larry Baxter

    2001-10-10

    This is the fifth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for firing US coals. The Electric Power Research Institute (EPRI) is providing cofunding for this program. This program contains multiple tasks and good progress is being made on all fronts. Field tests for NOx reduction in a cyclone fired utility boiler due to using Rich Reagent Injection (RRI) have been started. CFD modeling studies have been started to evaluate the use of RRI for NOx reduction in a corner fired utility boiler using pulverized coal. Field tests of a corrosion monitor to measure waterwall wastage in a utility boiler have been completed. Computational studies to evaluate a soot model within a boiler simulation program are continuing. Research to evaluate SCR catalyst performance has started. A literature survey was completed. Experiments have been outlined and two flow reactor systems have been designed and are under construction. Commercial catalyst vendors have been contacted about supplying catalyst samples. Several sets of new experiments have been performed to investigate ammonia removal processes and mechanisms for fly ash. Work has focused on a promising class of processes in which ammonia is destroyed by strong oxidizing agents at ambient temperature during semi-dry processing (the use of moisture amounts less than 5 wt-%). Both ozone and an ozone/peroxide combination have been used to treat both basic and acidic ammonia-laden ashes.

  12. NOx CONTROL OPTIONS AND INTEGRATION FOR US COAL FIRED BOILERS

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Marc Cremer; Kevin Davis; Connie Senior; Bob Hurt; Eric Eddings; Larry Baxter

    2001-10-10

    This is the fifth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for firing US coals. The Electric Power Research Institute (EPRI) is providing cofunding for this program. This program contains multiple tasks and good progress is being made on all fronts. Field tests for NOx reduction in a cyclone fired utility boiler due to using Rich Reagent Injection (RRI) have been started. CFD modeling studies have been started to evaluate the use of RRI for NOx reduction in a corner fired utility boiler using pulverized coal. Field tests of a corrosion monitor to measure waterwall wastage in a utility boiler have been completed. Computational studies to evaluate a soot model within a boiler simulation program are continuing. Research to evaluate SCR catalyst performance has started. A literature survey was completed. Experiments have been outlined and two flow reactor systems have been designed and are under construction. Commercial catalyst vendors have been contacted about supplying catalyst samples. Several sets of new experiments have been performed to investigate ammonia removal processes and mechanisms for fly ash. Work has focused on a promising class of processes in which ammonia is destroyed by strong oxidizing agents at ambient temperature during semi-dry processing (the use of moisture amounts less than 5 wt-%). Both ozone and an ozone/peroxide combination have been used to treat both basic and acidic ammonia-laden ashes.

  13. Geochemical modeling of fluid-fluid and fluid-mineral interactions during geological CO2 storage

    Science.gov (United States)

    Zhu, C.; Ji, X.; Lu, P.

    2013-12-01

    The long time required for effective CO2 storage makes geochemical modeling an indispensable tool for CCUS. One area of geochemical modeling research that is in urgent need is impurities in CO2 streams. Permitting impurities, such as H2S, in CO2 streams can lead to potential capital and energy savings. However, predicting the consequences of co-injection of CO2 and impurities into geological formations requires the understanding of the phase equilibrium and fluid-fluid interactions. To meet this need, we developed a statistical associating fluid theory (SAFT)-based equation of state (EOS) for the H2S-CO2-H2O-NaCl system at 373.15 dew pressures decrease with increasing H2S content, while the mass density increases at low pressures and decreases at high pressures. Furthermore, the EoS can be incorporated into reservoir simulators so that the dynamic development of mixed fluid plumes in the reservoir can be simulated. Accurate modeling of fluid-mineral interactions must confront unresolved uncertainties of silicate dissolution - precipitation reaction kinetics. Most prominent among these uncertainties is the well-known lab-field apparent discrepancy in dissolution rates. Although reactive transport models that simulate the interactions between reservoir rocks and brine, and their attendant effects on porosity and permeability changes, have proliferated, whether these results have acceptable uncertainties are unknown. We have conducted a series of batch experiments at elevated temperatures and numerical simulations of coupled dissolution and precipitation reactions. The results show that taking into account of reaction coupling is able to reduce the gap between the field and lab rates by about two orders of magnitude at elevated temperatures of 200-300 oC. Currently, we are using Si isotopes as a new tool to unravel the coupled reactions in ambient temperature laboratory experiments. These new experimental data, together with coupled reactive mass transport modeling

  14. Theoretical Convective Heat Transfer Model Developement of Cold Storage Using Taguchi Analysis.

    Directory of Open Access Journals (Sweden)

    Dr.N.Mukhopadhyay

    2015-01-01

    Full Text Available Energy crisis is one of the most important problems the world is facing now-a-days. With the increase of cost of electrical energy operating cost of cold storage storing is increasing which forces the increased cost price of the commodities that are kept. In this situation if the maximum heat energy(Q is absorbed by the evaporator inside the cold room through convective heat transfer process in terms of –heat transfer due to convection and heat transfer due to condensation, more energy has to be wasted to maintain the evaporator space at the desired temperature range of 2- 8 degree centigrade. In this paper we have proposed a theoretical heat transfermodel of convective heat transfer incold storage using Taguchi L9 orthogonal array. Velocity of air(V, Temperature difference(dT, RelativeHumidity(RHare the basic variable and three ranges are taken each of them in the model development. Graphical interpretations from the model justifies the reality

  15. CRYPTOGRAPHIC SECURE CLOUD STORAGE MODEL WITH ANONYMOUS AUTHENTICATION AND AUTOMATIC FILE RECOVERY

    Directory of Open Access Journals (Sweden)

    Sowmiya Murthy

    2014-10-01

    Full Text Available We propose a secure cloud storage model that addresses security and storage issues for cloud computing environments. Security is achieved by anonymous authentication which ensures that cloud users remain anonymous while getting duly authenticated. For achieving this goal, we propose a digital signature based authentication scheme with a decentralized architecture for distributed key management with multiple Key Distribution Centers. Homomorphic encryption scheme using Paillier public key cryptosystem is used for encrypting the data that is stored in the cloud. We incorporate a query driven approach for validating the access policies defined by an individual user for his/her data i.e. the access is granted to a requester only if his credentials matches with the hidden access policy. Further, since data is vulnerable to losses or damages due to the vagaries of the network, we propose an automatic retrieval mechanism where lost data is recovered by data replication and file replacement with string matching algorithm. We describe a prototype implementation of our proposed model.

  16. Modeling crack growth during Li insertion in storage particles using a fracture phase field approach

    Science.gov (United States)

    Klinsmann, Markus; Rosato, Daniele; Kamlah, Marc; McMeeking, Robert M.

    2016-07-01

    Fracture of storage particles is considered to be one of the major reasons for capacity fade and increasing power loss in many commercial lithium ion batteries. The appearance of fracture and cracks in the particles is commonly ascribed to mechanical stress, which evolves from inhomogeneous swelling and shrinkage of the material when lithium is inserted or extracted. Here, a coupled model of lithium diffusion, mechanical stress and crack growth using a phase field method is applied to investigate how the formation of cracks depends on the size of the particle and the presence or absence of an initial crack, as well as the applied flux at the boundary. The model shows great versatility in that it is free of constraints with respect to particle geometry, dimension or crack path and allows simultaneous observation of the evolution of lithium diffusion and crack growth. In this work, we focus on the insertion process. In particular, we demonstrate the presence of intricate fracture phenomena, such as, crack branching or complete breakage of storage particles within just a single half cycle of lithium insertion, a phenomenon that was only speculated about before.

  17. Spin decoherence in electron storage rings. More from a simple model

    Energy Technology Data Exchange (ETDEWEB)

    Barber, D.P. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Heinemann, K. [The Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mathematics and Statistics

    2015-06-15

    This is an addendum to the paper ''Some models of spin coherence and decoherence in storage rings'' by one of the authors (K. Heinemann, DESY Report 97-166 (1997)), in which spin diffusion in simple electron storage rings is studied. In particular, we illustrate in a compact way, namely that the exact formalism of this article delivers a rate of depolarisation which can differ from that obtained by the conventional treatments of spin diffusion which rely on the use of the derivative ∂n/∂η. As a vehicle we consider a ring with a Siberian Snake and electron polarisation in the plane of the ring. For this simple setup with its one-dimensional spin motion, we avoid having to deal directly with the Bloch equation for the polarisation density. Our treatment, which is deliberately pedagogical, shows that the use of ∂n/∂η provides a very good approximation to the rate of spin depolarisation in the model considered. But it then shows that the exact rate of depolarisation can be obtained by replacing ∂n/∂η by another derivative, while giving a heuristic justification for the new derivative.

  18. Spin decoherence in electron storage rings --- more from a simple model

    CERN Document Server

    Barber, D P

    2015-01-01

    This is an addendum to the paper "Some models of spin coherence and decoherence in storage rings" by one of the authors [1] in which spin diffusion in simple electron storage rings is studied. In particular, we illustrate in a compact way, a key implication in the Epilogue of [1], namely that the exact formalism of [1] delivers a rate of depolarisation which can differ from that obtained by the conventional treatments of spin diffusion which rely on the use of the derivative $\\partial \\hat n/\\partial\\eta$ [2,3,4]. As a vehicle we consider a ring with a Siberian Snake and electron polarisation in the plane of the ring (Machine II in [1]). For this simple setup with its one-dimensional spin motion, we avoid having to deal directly with the Bloch equation [5,6] for the polarisation density. Our treatment, which is deliberately pedagogical, shows that the use of $\\partial \\hat n/\\partial\\eta$ provides a very good approximation to the rate of spin depolarisation in the model considered. But it then shows that the ...

  19. Investigating and modeling of the effects of condensate storage tank fire in a refinery

    Directory of Open Access Journals (Sweden)

    Mohammad Kamaei

    2015-12-01

    Full Text Available Background & objective: Oil storage tanks are major industrial facilities which always pose risks of toxic substance release, fires and explosions. Fire has been recognized as the most common risk associated with such facilities, while explosion is the most important one in terms of ability to claim human lives and damage property. The current study aimed at investigating and modeling the effects of fires occurring in a gas condensate tank farm, according to which the level of possible emergencies were specified using the guidelines provided by the Center for Chemical Process Safety. Lastly, control measures were recommended. Methods: In the present study, the release and leakage of gas condensate from floating roof tanks were assessed using HAZOP method. Then, using PHAST software, the amount of radiation intensity received by the surrounding environment was determined, safe boundaries were computed, and according to the CCPS standard the emergency levels were determined. Results: modeling was performed based on the maximum capacity of tanks for both cold and hot seasons. The results revealed that safe distance for a maximum amount of irradiation density (4 KW/m2 related to a sudden release were 60 and 140 meters, respectively. Conclusion: according to the current condition of the plants and storage tanks, a plan was recommended for emergency management and practical suggestions were provided to improve the reliability and consistency.

  20. Uptake and Storage of Anthropogenic CO2 in the Pacific Ocean Estimated Using Two Modeling Approaches

    Institute of Scientific and Technical Information of China (English)

    LI Yangchun; XU Yongfu

    2012-01-01

    A basin-wide ocean general circulation model (OGCM) of the Pacific Ocean is employed to estimate the uptake and storage of anthropogenic CO2 using two different simulation approaches.The simulation (named BIO) makes use of a carbon model with biological processes and full thermodynamic equations to calculate surface water partial pressure of CO2,whereas the other simulation (named PTB) makes use of a perturbation approach to calculate surface water partial pressure of anthropogenie CO2.The results from the two simulations agree well with the estimates based on observation data in most important aspects of the vertical distribution as well as the total inventory of anthropogenic carbon.The storage of anthropogenic carbon from BIO is closer to the observation-based estimate than that from PTB.The Revelle factor in 1994 obtained in BIO is generally larger than that obtained in PTB in the whole Pacific,except for the subtropical South Pacific.This,to large extent,leads to the difference in the surface anthropogenic CO2 concentration between the two runs.The relative difference in the annual uptake between the two runs is almost constant during the integration processes after 1850.This is probably not caused by dissolved inorganic carbon (DIC),but rather by a factor independent of time.In both runs,the rate of change in anthropogenic CO2 fluxes with time is consistent with the rate of change in the growth rate of atmospheric partial pressure of CO2.

  1. Experiments and simulations of NOx formation in the combustion of hydroxylated fuels

    KAUST Repository

    Bohon, Myles

    2015-06-01

    This work investigates the influence of molecular structure in hydroxylated fuels (i.e. fuels with one or more hydroxyl groups), such as alcohols and polyols, on NOx formation. The fuels studied are three lower alcohols (methanol, ethanol, and n-propanol), two diols (1,2-ethanediol and 1,2-propanediol), and one triol (1,2,3-propanetriol); all of which are liquids at room temperature and span a wide range of thermophysical properties. Experimental stack emissions measurements of NO/NO2, CO, and CO2 and flame temperature profiles utilizing a rake of thermocouples were obtained in globally lean, swirling, liquid atomized spray flames inside a refractory-lined combustion chamber as a function of the atomizing air flow rate and swirl number. These experiments show significantly lower NOx formation with increasing fuel oxygen content despite similarities in the flame temperature profiles. By controlling the temperature profiles, the contribution to NOx formation through the thermal mechanism were matched, and variations in the contribution through non-thermal NOx formation pathways are observed. Simulations in a perfectly stirred reactor, at conditions representative of those measured within the combustion region, were conducted as a function of temperature and equivalence ratio. The simulations employed a detailed high temperature chemical kinetic model for NOx formation from hydroxylated fuels developed based on recent alcohol combustion models and extended to include polyol combustion chemistry. These simulations provide a qualitative comparison to the range of temperatures and equivalence ratios observed in complex swirling flows and provide insight into the influence of variations in the fuel decomposition pathways on NOx formation. It is observed that increasing the fuel bound oxygen concentration ultimately reduces the formation of NOx by increasing the proportion of fuel oxidized through formaldehyde, as opposed to acetylene or acetaldehyde

  2. Physico-Chemical and Structural Properties of DeNOx and SO2 Oxidation Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen Grenville; Oehlers, Cord; Nielsen, Kurt;

    1996-01-01

    Commercial catalysts for NOx removal and SO2 oxidation and their model systems have been investigated by spectroscopic, thermal, electrochemical and X-ray methods. Structural information on the vanadium complexes and compounds as well as physico-chemical properties for catalyst model systems have...... been obtained. The results are discussed in relation to proposed reaction mechanisms....

  3. Storage stability of hen egg white powders in three protein/water dough model systems.

    Science.gov (United States)

    Rao, Qinchun; Rocca-Smith, Jeancarlo R; Labuza, Theodore P

    2013-06-01

    In recent years, due to the specific health benefits associated with bioactive peptides and the reduction of protein allergenicity by enzymatic hydrolysis, the utilisation of protein hydrolysates in the intermediate-moisture food (IMF) market, such as high protein nutrition bars (HPNB), has significantly increased. Currently, no reported study is related to the storage stability of dried hen egg white (DEW) and its hydrolysates (HEW) in an IMF matrix. Therefore, three DEW/HEW dough model systems (100%HEW+0%DEW, 75%HEW+25%DEW and 50%HEW+50%DEW) were established using two commercial spray-dried egg white powders to study the effect of temperature and fraction of HEW on these IMF models (water activity (a(w)): ∼0.8). During storage at three different temperatures (23, 35 and 45°C) for 70 days, the selected physicochemical properties of the dough systems were compared. Overall, kinetic analysis showed an apparent zero-order model fit for the change in the colour (L(∗)), fluorescence intensity (FI) and hardness, as a function of time, for different dough model systems. As expected, the L(∗), FI and hardness increased as a function of time mainly due to the Maillard reaction. The amount of free amino groups decreased, with an increase in rate of loss, as temperature increased in the 100%HEW+0%DEW model. When DEW was substituted for some HEW, the regeneration of the free amino groups after loss was observed as a function of time. Furthermore, when the percentage of HEW was decreased, the incidence of mouldy samples occurred sooner, which indicates that HEW has some antimicrobial ability, especially in the 100%HEW+0%DEW system where mould growth did not occur. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. ULTRA LOW NOx INTEGRATED SYSTEM FOR NOx EMISSION CONTROL FROM COAL-FIRED BOILERS

    Energy Technology Data Exchange (ETDEWEB)

    Galen H. Richards; Charles Q. Maney; Richard W. Borio; Robert D. Lewis

    2002-12-30

    ALSTOM Power Inc.'s Power Plant Laboratories, working in concert with ALSTOM Power's Performance Projects Group, has teamed with the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient NOx control technologies for retrofit to pulverized coal fired utility boilers. The objective of this project was to develop retrofit NOx control technology to achieve less than 0.15 lb/MMBtu NOx (for bituminous coals) and 0.10 lb/MMBtu NOx (for subbituminous coals) from existing pulverized coal fired utility boilers at a cost which is at least 25% less than SCR technology. Efficient control of NOx is seen as an important, enabling step in keeping coal as a viable part of the national energy mix in this century, and beyond. Presently 57% of U.S. electrical generation is coal based, and the Energy Information Agency projects that coal will maintain a lead in U.S. power generation over all other fuel sources for decades (EIA 1998 Energy Forecast). Yet, coal-based power is being strongly challenged by society's ever-increasing desire for an improved environment and the resultant improvement in health and safety. The needs of the electric-utility industry are to improve environmental performance, while simultaneously improving overall plant economics. This means that emissions control technology is needed with very low capital and operating costs. This project has responded to the industry's need for low NOx emissions by evaluating ideas that can be adapted to present pulverized coal fired systems, be they conventional or low NOx firing systems. The TFS 2000{trademark} firing system has been the ALSTOM Power Inc. commercial offering producing the lowest NOx emission levels. In this project, the TFS 2000{trademark} firing system served as a basis for comparison to other low NOx systems evaluated and was the foundation upon which refinements were made to further

  5. Commercial introduction of the Advanced NOxTECH system

    Energy Technology Data Exchange (ETDEWEB)

    Sudduth, B.C. [NOxTECH, Inc., Irvine, CA (United States)

    1997-12-31

    NOxTECH is BACT for diesel electric generators. Emissions of NO{sub x} are reduced 95% or more with substantial concurrent reductions in CO, particulates, and ROG`s. No engine modifications or other exhaust aftertreatments can remove all criteria pollutants as effectively as NOxTECH. The NOxTECH system reliably maintains NH{sub 3} slip below 2 ppm. Unlike other emissions controls, NOxTECH does not generate hazardous by-products. The Advanced NOxTECH system reduces the size, weight, and cost for BACT emissions reductions. Based on the operation of a 150 kW prototype, NOxTECH, Inc. is quoting commercial units for diesel electric generators. Advanced NOxTECH equipment costs about half as much as SCR systems, and NO{sub x} reduction can exceed 95% with guarantees for emissions compliance.

  6. Myocardin-related transcription factor regulates Nox4 protein expression

    DEFF Research Database (Denmark)

    Rozycki, Matthew; Bialik, Janne Folke; Speight, Pam

    2016-01-01

    TGFβ-induced expression of the NADPH oxidase Nox4 is essential for fibroblast-myofibroblast transition. Rho has been implicated in Nox4 regulation, but the underlying mechanisms are largely unknown. Myocardin-related transcription factor (MRTF), a Rho/actin polymerization-controlled coactivator...... translocation of MRTF. Because the Nox4 promoter harbors a serum response factor/MRTF cis-element (CC(A/T)6GG box), we asked if MRTF (and thus cytoskeleton organization) could regulate Nox4 expression. We show that Nox4 protein is robustly induced in kidney tubular cells exclusively by combined application...... of contact uncoupling and TGFβ. Nox4 knockdown abrogates epithelial-myofibroblast transition-associated reactive oxygen species production. Laser capture microdissection reveals increased Nox4 expression in the tubular epithelium also during obstructive nephropathy. MRTF down-regulation/inhibition suppresses...

  7. Carbonates-based noble metal-free lean NOx trap catalysts MOx-K2CO3/K2Ti8O17 (M = Ce, Fe, Cu, Co) with superior catalytic performance

    Science.gov (United States)

    Zhang, Yuxia; You, Rui; Liu, Dongsheng; Liu, Cheng; Li, Xingang; Tian, Ye; Jiang, Zheng; Zhang, Shuo; Huang, Yuying; Zha, Yuqing; Meng, Ming

    2015-12-01

    A series of base metal-based lean NOx trap (LNT) catalysts MOx-K2CO3/K2Ti8O17 (M = Ce, Fe, Cu, Co) were synthesized by successive impregnations and employed for the storage and reduction of NOx in the emissions of lean-burn engines at 350 °C. The XRD and XANES/EXAFS results reveal that the active phases in the corresponding catalysts exist as CeO2, Fe2O3, CuO and Co3O4, respectively. Among all the catalysts, CoOx-K2CO3/K2Ti8O17 exhibits the best performance, which cannot only trap the NOx quickly and completely at lean condition, giving the highest storage capacity (3.32 mmol/g) reported so far, but also reduce the NOx at rich condition, showing a NOx reduction percentage as high as 99.0%. Meanwhile, this catalyst displays an ultralow NOx to N2O selectivity (0.3%) during NOx reduction. The excellent performance of CoOx-K2CO3/K2Ti8O17 results from its largest amount of surface active oxygen species as revealed by XPS, O2-TPD and NO-TPD. HRTEM, FT-IR and CO2-TPD results illustrate that several kinds of K species such as sbnd OK groups, K2O, surface carbonates and bulk or bulk-like carbonates coexist in the catalysts. Based upon the in situ DRIFTS results, the participation of K2CO3 in NOx storage is confirmed, and the predominant NOx storage species is revealed as bidentate nitrites formed via multiple kinetic pathways. The low cost and high catalytic performance of the CoOx-based LNT catalyst make it most promising for the substitution of noble metal-based LNT catalysts.

  8. ESTIMASI NILAI PENURUNAN KESEHATAN AKIBAT POLUSI GAS NOX DI UDARA DKI JAKARTA

    Directory of Open Access Journals (Sweden)

    Sri Listyarini

    2016-09-01

    Full Text Available The aim of this research is to estimate the value of health degradation caused by nitrogen oxide (NOx gas as one of the air pollutions in Jakarta Province. The economic growth in urban area may affect lifestyle which will increase the energy demand. Fossil fuel as the main energy emitting some gases to the ambient, one of them is NOx gas.  In this research analysis of factors that influenced NOx ambient concentration is based on the socials, economics, and meteorological data from Indonesia Statistics Center (BPS and Bureau of Meteorology and Geophysics (BMG. The prediction of the cost that has to be paid by the persons who are exposured by NOx gas and will get respiratory symptomps is done by developing the dynamic simulation model. The result of this research is by 2025 the Jakarta residences that will have respiratory symptomps caused by the NOx air pollution should pay about 1 trillion (1012 rupiahs. To reduce this pollutant it is recommended to develop public policies based on the economic and environmental concern.

  9. A new meta-data driven data-sharing storage model for SaaS

    Directory of Open Access Journals (Sweden)

    Li Heng

    2012-11-01

    Full Text Available A multi-tenant database is the primary characteristic of SaaS, it allows SaaS vendors to run a single instance application which supports multiple tenants on the same hardware and software infrastructure. This application should be highly customizable to meet tenants expectations and business requirements. This paper examined current solutions on multi-tenancy, and proposed a new meta-data driven data-sharing storage model for multi-tenant applications. Our design enables tenants to extend their own database schema during multi-tenant application run-time execution to satisfy their business needs. Experimental results show that our model made a good balance between efficiency and customized.

  10. Disease Modeling and Gene Therapy of Copper Storage Disease in Canine Hepatic Organoids

    Directory of Open Access Journals (Sweden)

    Sathidpak Nantasanti

    2015-11-01

    Full Text Available The recent development of 3D-liver stem cell cultures (hepatic organoids opens up new avenues for gene and/or stem cell therapy to treat liver disease. To test safety and efficacy, a relevant large animal model is essential but not yet established. Because of its shared pathologies and disease pathways, the dog is considered the best model for human liver disease. Here we report the establishment of a long-term canine hepatic organoid culture allowing undifferentiated expansion of progenitor cells that can be differentiated toward functional hepatocytes. We show that cultures can be initiated from fresh and frozen liver tissues using Tru-Cut or fine-needle biopsies. The use of Wnt agonists proved important for canine organoid proliferation and inhibition of differentiation. Finally, we demonstrate that successful gene supplementation in hepatic organoids of COMMD1-deficient dogs restores function and can be an effective means to cure copper storage disease.

  11. Simplified models of transport and reactions in conditions of CO2 storage in saline aquifers

    Science.gov (United States)

    Suchodolska, Katarzyna; Labus, Krzysztof

    2016-04-01

    Simple hydrogeochemical models may serve as tools of preliminary assessment of CO2 injection and sequestraton impact on the aquifer and cap-rocks. In order to create models of reaction and transport in conditions of CO2 injection and storage, the TOUGHREACT simulator, and the Geochemist's Workbench software were applied. The chemical composition of waters for kinetic transport models based on the water - rock equilibrium calculations. Analyses of reaction and transport of substances during CO2 injection and storage period were carried out in three scenarios: one-dimensional radial model, and two-dimensional model of CO2 injection and sequestration, and one-dimensional model of aquifer - cap-rock interface. Modeling was performed in two stages. The first one simulated the immediate changes in the aquifer and insulating rocks impacted by CO2 injection (100 days in case of reaction model and 30 years in transport and reaction model), the second - enabled assessment of long-term effects of sequestration (20000 years). Reactions' quality and progress were monitored and their effects on formation porosity and sequestration capacity in form of mineral, residual and free phase of CO2 were calculated. Calibration of numerical models (including precipitation of secondary minerals, and correction of kinetics parameters) describing the initial stage of injection, was based on the experimental results. Modeling allowed to evaluate the pore space saturation with gas, changes in the composition and pH of pore waters, relationships between porosity and permeability changes and crystallization or dissolution minerals. We assessed the temporal and spatial extent of crystallization processes, and the amount of carbonates trapping. CO2 in mineral form. The calculated sequestration capacity of analyzed formations reached n·100 kg/m3 for the: dissolved phase - CO(aq), gas phase - CO2(g) and mineral phase, but as much as 101 kg/m3 for the supercritical phase - SCCO2. Processes of gas

  12. Energy Storage.

    Science.gov (United States)

    Eaton, William W.

    Described are technological considerations affecting storage of energy, particularly electrical energy. The background and present status of energy storage by batteries, water storage, compressed air storage, flywheels, magnetic storage, hydrogen storage, and thermal storage are discussed followed by a review of development trends. Included are…

  13. Modelling moisture content and dry matter loss during storage of logging residues for energy

    Energy Technology Data Exchange (ETDEWEB)

    Filbakk, Tore; Hoeiboe, Olav Albert (Dept. of Ecology and Natural Resource Management, Norwegian Univ. of Life Sciences, Aas (Norway)); Dibdiakova, Janka (Norwegian Forest and Landscape Inst., Aas (Norway)); Nurmi, Juha (Finnish Forest Research Inst., Kannus (Finland))

    2011-04-15

    To achieve optimal utilisation of logging residues for energy, it is important to know how different handling and storage methods affect fuel properties. The aim of this study was to model how the moisture content and dry matter losses of logging residues develop during storage. Logging residues were collected from five different stands of spruce and pine during different seasons of the year and stored in the same location. The logging residues were stored in covered piles of bundled residues and loose residues. Only minor differences were found in the moisture content profiles between piles of bundles and loose residues. Logging residues located in the centre of both types of piles had considerably lower moisture content than the outer parts. The moisture content significantly affected dry matter loss, with the highest dry matter losses being found in the samples with the least favourable drying conditions. The dry matter losses varied between 1 and 3% per month. Significantly higher dry matter losses were found in the spruce bundles than in the pine bundles. Seasoned logging residues had the lowest dry matter loss, while the logging residues harvested and piled in the autumn had the highest loss

  14. A double-superconducting axial bearing system for an energy storage flywheel model

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z; Lin, Q; Ma, G; Zheng, J; Zhang, Y; Wang, S; Wang, J [Applied Superconductivity Laboratory, Mail Stop 152, Southwest Jiaotong University, Chengdu, 610031 (China)], E-mail: jsywang@home.swjtu.edu.cn

    2008-02-15

    The bulk high temperature superconductors (HTSCs) with unique flux-pinning property have been applied to fabricate two superconducting axial bearings for an energy storage flywheel model. The two superconducting axial bearings are respectively fixed at two ends of the vertical rotational shaft, whose stator is composed of seven melt-textured YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) bulks with diameter of 30 mm, height of 18 mm and rotor is made of three cylindrical axial-magnetized NdFeB permanent magnets (PM) by superposition with diameter of 63 mm, height of 27 mm. The experimental results show the total levitation and lateral force produced by the two superconducting bearings are enough to levitate and stabilize the 2.4 kg rotational shaft. When the two YBCO stators were both field cooled to the liquid nitrogen temperature at respective axial distances above or below the PM rotor, the shaft could be automatically levitated between the two stators without any contact. In the case of a driving motor, it can be stably rotated along the central axis besides the resonance frequency. This double-superconducting axial bearing system can be used to demonstrate the flux-pinning property of bulk HTSC for stable levitation and suspension and the principle of superconducting flywheel energy storage system to visitors.

  15. Alternative deNOx catalysts and technologies

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    in the formation of acid rain and photochemical smog. Some basic concepts and reactions regarding the formation and removal of NOx are presented in chapter 1 and 2. Two approaches are undertaken in the present work to reduce the emission of NOx: by means of catalytic removal, and by NO absorption in ionic liquids...... a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different...... permolecule ionic liquid. However, [BMIM]OTf exhibited promising behavior due to its reversible absorption/desorption properties. This in principle allows recycling of the ionic liquid as well as harvesting the NO. The accumulated NO could hereby be used in e.g. the synthesis of nitric acid allowing...

  16. Photosynthetic Energy Storage for the Built Environment: Modeling Energy Generation and Storage for Net-Zero Analysis

    Science.gov (United States)

    Lichter-Marck, Eli Morris

    There is a growing need to address the energy demand of the building sector with non-polluting, renewable energy sources. The Net Zero Energy Building (NZEB) mandate seeks to reduce the impact of building sector energy consumption by encouraging on-site energy generation as a way to offset building loads. However, current approaches to designing on-site generation fail to adequately match the fluctuating load schedules of the built environment. As a result, buildings produce highly variable and often-unpredictable energy import/export patterns that create stress on energy grids and increase building dependence on primary energy resources. This research investigates the potential of integrating emerging photo-electrochemical (PEC) technologies into on-site generation systems as a way to enable buildings to take a more active role in collecting, storing and deploying energy resources according to their own demand schedules. These artificially photosynthetic systems have the potential to significantly reduce variability in hour-to-hour and day-to-day building loads by introducing high-capacity solar-hydrogen into the built environment context. The Building Integrated Artificial Photosynthesis (BIAP) simulation framework presented here tests the impact of hydrogen based energy storage on NZEB performance metrics with the goal of developing a methodology that makes on-site energy generation more effective at alleviating excessive energy consumption in the building sector. In addition, as a design performance framework, the BIAP framework helps guide how material selection and scale up of device design might tie photo-electrochemical devices into parallel building systems to take full advantage of the potential outputs of photosynthetic building systems.

  17. A New Model for Gas Transfer and Storage in a Permeable Volcanic Edifice

    Science.gov (United States)

    Collinson, A. D.; Neuberg, J.

    2011-12-01

    There is a marked contrast between the behaviour of a volcano in an open system compared to one which is closed. It is therefore essential to understand degassing, to appreciate how much gas is lost and where. Previous studies by a variety of scientists have led to the accumulation of data via field evidence from both active and fossil volcanoes (Stasiuk et al., 1996), laboratory experiments (Moore et al., 1994) and conceptual modelling, in which Darcy's law has become increasingly applicable (Eichelberger et al., 1986; Edmonds et al., 2003). Of particular interest for this study, is the effect different permeabilities have on the degree and pattern of the gas flux. A new method has been devised to investigate gas transport and storage in a permeable volcanic edifice. The continuity equation and Darcy's law are amalgamated to derive a partial differential equation which is solved using a finite element method to obtain the gas pressure. The associated pressure gradient is then used within Darcy's law to calculate the gas flux. The properties of the gas are described by the ideal gas law. The strength of this method is that it allows the modelling of two and three dimensional structures both in stationary equilibrium and as a time dependent progression. A geometry is created and the pressure and permeabilites incorporated into the model as boundary and domain conditions respectively. The aim of the model is to investigate how variable permeability and pressure gradients influence the gas flux, for example highly permeable cracks in the dome, or impermeable layers within the volcanic structure. We also use this gas model to complement the model of Neuberg et al. (2006) in which brittle failure of the conduit-wall boundary is used as a trigger mechanism of low-frequency earthquakes. The associated behaviour of the gas in response to the brittle failure is simulated in our model by increasing the permeability through a narrow zone at the boundary between the conduit

  18. Enhanced Identification of hydrologic models using streamflow and satellite water storage data: a multi-objective calibration approach

    Science.gov (United States)

    Yassin, F. A.; Razavi, S.; Sapriza, G.; Wheater, H. S.

    2015-12-01

    The conventional procedure for parameter identification of hydrological processes through conditioning only to streamflow data is challenging in physically based distributed hydrologic modelling. The challenge increases for modeling the landscapes where vertical processes dominate horizontal processes, leading to high uncertainties in modelled state variables, vertical fluxes and hence parameter estimates. Such behavior is common in modeling the prairie region of the Saskatchewan River Basin (SaskRB, our case study), Canada, where hydrologic connectivity and vertical fluxes are mainly controlled by surface and sub-surface water storage. To address this challenge, we developed a novel multi-criteria framework that utilizes total column water storage derived from the GRACE satellite, in addition to streamflows. We used a multi-objective optimization algorithm (Borg) and a recently-developed global sensitivity analysis approach (VARS) to effectively identify the model parameters and characterize their significance in model performance. We applied this framework in the calibration of a Land Surface Scheme-Hydrology model, MESH (Modélisation Environmentale Communautaire - Surface and Hydrology) to a sub-watershed of SaskRB. Results showed that the developed framework is superior to the conventional approach of calibration to streamflows. The new framework allowed us to find optimal solutions that effectively constrain the posterior parameter space and are representative of storage and streamflow performance criteria, yielding more credible prediction with reduced uncertainty of modeled storage and evaporation.

  19. Divergent predictions of carbon storage between two global land models: attribution of the causes through traceability analysis

    Science.gov (United States)

    Rafique, Rashid; Xia, Jianyang; Hararuk, Oleksandra; Asrar, Ghassem R.; Leng, Guoyong; Wang, Yingping; Luo, Yiqi

    2016-07-01

    Representations of the terrestrial carbon cycle in land models are becoming increasingly complex. It is crucial to develop approaches for critical assessment of the complex model properties in order to understand key factors contributing to models' performance. In this study, we applied a traceability analysis which decomposes carbon cycle models into traceable components, for two global land models (CABLE and CLM-CASA') to diagnose the causes of their differences in simulating ecosystem carbon storage capacity. Driven with similar forcing data, CLM-CASA' predicted ˜ 31 % larger carbon storage capacity than CABLE. Since ecosystem carbon storage capacity is a product of net primary productivity (NPP) and ecosystem residence time (τE), the predicted difference in the storage capacity between the two models results from differences in either NPP or τE or both. Our analysis showed that CLM-CASA' simulated 37 % higher NPP than CABLE. On the other hand, τE, which was a function of the baseline carbon residence time (τ'E) and environmental effect on carbon residence time, was on average 11 years longer in CABLE than CLM-CASA'. This difference in τE was mainly caused by longer τ'E of woody biomass (23 vs. 14 years in CLM-CASA'), and higher proportion of NPP allocated to woody biomass (23 vs. 16 %). Differences in environmental effects on carbon residence times had smaller influences on differences in ecosystem carbon storage capacities compared to differences in NPP and τ'E. Overall, the traceability analysis showed that the major causes of different carbon storage estimations were found to be parameters setting related to carbon input and baseline carbon residence times between two models.

  20. PVN adenovirus-siRNA injections silencing either NOX2 or NOX4 attenuate aldosterone/NaCl-induced hypertension in mice.

    Science.gov (United States)

    Xue, Baojian; Beltz, Terry G; Johnson, Ralph F; Guo, Fang; Hay, Meredith; Johnson, Alan Kim

    2012-02-01

    Mineralocorticoid excess increases superoxide production by activating NADPH oxidase (NOX), and intracerebroventricular infusions of NADPH oxidase inhibitors attenuate aldosterone (Aldo)/salt-induced hypertension. It has been hypothesized that increased reactive oxygen species (ROS) in the brain may be a key mechanism in the development of hypertension. The present study investigated the brain regional specificity of NADPH oxidase and the role of NOX2 and NOX4 NADPH oxidase subunits in the hypothalamic paraventricular nucleus (PVN) in Aldo/salt-induced hypertension. PVN injections of adenoviral vectors expressing small interfering (si)RNA targeting NOX2 (AdsiRNA-NOX2) or NOX4 (AdsiRNA-NOX4) mRNAs were used to knock down NOX2 and NOX4 proteins. Three days later, delivery of Aldo (0.2 mg·kg(-1)·day(-1) sc) via osmotic pump commenced and 1% NaCl was provided in place of water. PVN injections of either AdsiRNA-NOX2 or AdsiRNA-NOX4 significantly attenuated the development of Aldo/NaCl-induced hypertension. In an additional study, Aldo/salt-induced hypertension was also significantly attenuated in NOX2 (genomic) knockout mice compared with wild-type controls. When animals from both functional studies underwent ganglionic blockade, there was a reduced fall in blood pressure in the NOX2 and NOX4 knockdown/knockout mice. Western blot analyses of the PVN of siRNA-NOX2- or siRNA-NOX4-injected mice confirmed a marked reduction in the expression of NOX2 or NOX4 protein. In cultured PVN neurons, silencing either NOX2 or NOX4 protein production by culturing PVN cells with siRNA-NOX2 or siRNA-NOX4 attenuated Aldo-induced ROS. These data indicate that both NOX2 and NOX4 in the PVN contribute to elevated sympathetic activity and the hypertensivogenic actions induced by mineralocorticoid excess.

  1. Measurement and Modeling of Respiration Rate of Tomato (Cultivar Roma) for Modified Atmosphere Storage.

    Science.gov (United States)

    Kandasamy, Palani; Moitra, Ranabir; Mukherjee, Souti

    2015-01-01

    Experiments were conducted to determine the respiration rate of tomato at 10, 20 and 30 °C using closed respiration system. Oxygen depletion and carbon dioxide accumulation in the system containing tomato was monitored. Respiration rate was found to decrease with increasing CO2 and decreasing O2 concentration. Michaelis-Menten type model based on enzyme kinetics was evaluated using experimental data generated for predicting the respiration rate. The model parameters that obtained from the respiration rate at different O2 and CO2 concentration levels were used to fit the model against the storage temperatures. The fitting was fair (R2 = 0.923 to 0.970) when the respiration rate was expressed as O2 concentation. Since inhibition constant for CO2 concentration tended towards negetive, the model was modified as a function of O2 concentration only. The modified model was fitted to the experimental data and showed good agreement (R2 = 0.998) with experimentally estimated respiration rate.

  2. Flexibility on storage-release based distributed hydrologic modeling with object-oriented approach

    Science.gov (United States)

    Kang, Kwangmin; Merwade, Venkatesh; Chun, Jong Ahn; Timlin, Dennis

    2016-09-01

    With the availability of advanced hydrologic data in public domain such as remote sensed and climate change scenario data, there is a need for a modeling framework that is capable of using these data to simulate and extend hydrologic processes with multidisciplinary approaches for sustainable water resources management. To address this need, a storage-release based distributed hydrologic model (STORE DHM) is developed based on an object-oriented approach. The model is tested for demonstrating model flexibility and extensibility to know how to well integrate object-oriented approach to further hydrologic research issues, e.g., reconstructing missing precipitation in this study, without changing its main frame. Moreover, the STORE DHM is applied to simulate hydrological processes with multiple classes in the Nanticoke watershed. This study also describes a conceptual and structural framework of object-oriented inheritance and aggregation characteristics under the STORE DHM. In addition, NearestMP (missing value estimation based on nearest neighborhood regression) and KernelMP (missing value estimation based on Kernel Function) are proposed for evaluating STORE DHM flexibility. And then, STORE DHM runoff hydrographs compared with NearestMP and KernelMP runoff hydrographs. Overall results from these comparisons show promising hydrograph outputs generated by the proposed two classes. Consequently, this study suggests that STORE DHM with an object-oriented approach will be a comprehensive water resources modeling tools by adding additional classes for toward developing through its flexibility and extensibility.

  3. Modeling evaporation from spent nuclear fuel storage pools: A diffusion approach

    Science.gov (United States)

    Hugo, Bruce Robert

    Accurate prediction of evaporative losses from light water reactor nuclear power plant (NPP) spent fuel storage pools (SFPs) is important for activities ranging from sizing of water makeup systems during NPP design to predicting the time available to supply emergency makeup water following severe accidents. Existing correlations for predicting evaporation from water surfaces are only optimized for conditions typical of swimming pools. This new approach modeling evaporation as a diffusion process has yielded an evaporation rate model that provided a better fit of published high temperature evaporation data and measurements from two SFPs than other published evaporation correlations. Insights from treating evaporation as a diffusion process include correcting for the effects of air flow and solutes on evaporation rate. An accurate modeling of the effects of air flow on evaporation rate is required to explain the observed temperature data from the Fukushima Daiichi Unit 4 SFP during the 2011 loss of cooling event; the diffusion model of evaporation provides a significantly better fit to this data than existing evaporation models.

  4. Modeling a reversible solid oxide fuel cell as a storage device within AC power networks

    Energy Technology Data Exchange (ETDEWEB)

    Ren, J.; Roscoe, A.J.; Burt, G. [Department of Electronic and Electrical Engineering, Royal College, University of Strathclyde, Glasgow (United Kingdom); Gamble, S.R.; Irvine, J.T.S. [School of Chemistry, University of St. Andrews, Purdie Building, St. Andrews (United Kingdom)

    2012-10-15

    A reversible solid oxide fuel cell (RSOFC) system, consisting of a RSOFC stack, heat store, and electrical inverters to convert DC to AC power, is shown by computer modeling to have the potential to efficiently store electrical energy. This paper describes the modeling of a single RSOFC, based on a proposed cell geometry, empirical data on the resistivities of the components, and calculation of activation and diffusion polarization resistances from electrochemical theory. Data from ac impedance spectroscopy measurements on symmetrical cells are used to model RSOFC impedance. A RSOFC stack is modeled by electrically linking the individual cells inside a pressurized vessel. A phase change heat store is added to improve energy storage efficiency. The model is implemented in MATLAB {sup registered} /Simulink {sup registered}. Two competing inverter control schemes are compared, trading off DC bus ripple against AC power quality. It is found that selection of appropriate DC bus capacitance is important in certain scenarios, with potential system cost implications. It is shown that the system can store electrical energy at an efficiency of 64% over a single discharge-charge cycle, i.e., hydrogen to electricity and heat to hydrogen. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Discovery of Novel Complex Metal Hydrides for Hydrogen Storage through Molecular Modeling and Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lesch, David A; Adriaan Sachtler, J.W. J.; Low, John J; Jensen, Craig M; Ozolins, Vidvuds; Siegel, Don; Harmon, Laurel

    2011-02-14

    UOP LLC, a Honeywell Company, Ford Motor Company, and Striatus, Inc., collaborated with Professor Craig Jensen of the University of Hawaii and Professor Vidvuds Ozolins of University of California, Los Angeles on a multi-year cost-shared program to discover novel complex metal hydrides for hydrogen storage. This innovative program combined sophisticated molecular modeling with high throughput combinatorial experiments to maximize the probability of identifying commercially relevant, economical hydrogen storage materials with broad application. A set of tools was developed to pursue the medium throughput (MT) and high throughput (HT) combinatorial exploratory investigation of novel complex metal hydrides for hydrogen storage. The assay programs consisted of monitoring hydrogen evolution as a function of temperature. This project also incorporated theoretical methods to help select candidate materials families for testing. The Virtual High Throughput Screening served as a virtual laboratory, calculating structures and their properties. First Principles calculations were applied to various systems to examine hydrogen storage reaction pathways and the associated thermodynamics. The experimental program began with the validation of the MT assay tool with NaAlH4/0.02 mole Ti, the state of the art hydrogen storage system given by decomposition of sodium alanate to sodium hydride, aluminum metal, and hydrogen. Once certified, a combinatorial 21-point study of the NaAlH4 LiAlH4Mg(AlH4)2 phase diagram was investigated with the MT assay. Stability proved to be a problem as many of the materials decomposed during synthesis, altering the expected assay results. This resulted in repeating the entire experiment with a mild milling approach, which only temporarily increased capacity. NaAlH4 was the best performer in both studies and no new mixed alanates were observed, a result consistent with the VHTS. Powder XRD suggested that the reverse reaction, the regeneration of the

  6. Discovery of Novel Complex Metal Hydrides for Hydrogen Storage through Molecular Modeling and Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lesch, David A; Adriaan Sachtler, J.W. J.; Low, John J; Jensen, Craig M; Ozolins, Vidvuds; Siegel, Don; Harmon, Laurel

    2011-02-14

    UOP LLC, a Honeywell Company, Ford Motor Company, and Striatus, Inc., collaborated with Professor Craig Jensen of the University of Hawaii and Professor Vidvuds Ozolins of University of California, Los Angeles on a multi-year cost-shared program to discover novel complex metal hydrides for hydrogen storage. This innovative program combined sophisticated molecular modeling with high throughput combinatorial experiments to maximize the probability of identifying commercially relevant, economical hydrogen storage materials with broad application. A set of tools was developed to pursue the medium throughput (MT) and high throughput (HT) combinatorial exploratory investigation of novel complex metal hydrides for hydrogen storage. The assay programs consisted of monitoring hydrogen evolution as a function of temperature. This project also incorporated theoretical methods to help select candidate materials families for testing. The Virtual High Throughput Screening served as a virtual laboratory, calculating structures and their properties. First Principles calculations were applied to various systems to examine hydrogen storage reaction pathways and the associated thermodynamics. The experimental program began with the validation of the MT assay tool with NaAlH4/0.02 mole Ti, the state of the art hydrogen storage system given by decomposition of sodium alanate to sodium hydride, aluminum metal, and hydrogen. Once certified, a combinatorial 21-point study of the NaAlH4 LiAlH4Mg(AlH4)2 phase diagram was investigated with the MT assay. Stability proved to be a problem as many of the materials decomposed during synthesis, altering the expected assay results. This resulted in repeating the entire experiment with a mild milling approach, which only temporarily increased capacity. NaAlH4 was the best performer in both studies and no new mixed alanates were observed, a result consistent with the VHTS. Powder XRD suggested that the reverse reaction, the regeneration of the

  7. Modeling wood dynamics, jam formation, and sediment storage in a gravel-bed stream

    Science.gov (United States)

    Eaton, B. C.; Hassan, M. A.; Davidson, S. L.

    2012-12-01

    In small and intermediate sized streams, the interaction between wood and bed material transport often determines the nature of the physical habitat, which in turn influences the health of the stream's ecosystem. We present a stochastic model that can be used to simulate the effects on physical habitat of forest fires, climate change, and other environmental disturbances that alter wood recruitment. The model predicts large wood (LW) loads in a stream as well as the volume of sediment stored by the wood; while it is parameterized to describe gravel bed streams similar to a well-studied field prototype, Fishtrap Creek, British Columbia, it can be calibrated to other systems as well. In the model, LW pieces are produced and modified over time as a result of random tree-fall, LW breakage, LW movement, and piece interaction to form LW jams. Each LW piece traps a portion of the annual bed material transport entering the reach and releases the stored sediment when the LW piece is entrained and moved. The equations governing sediment storage are based on a set of flume experiments also scaled to the field prototype. The model predicts wood loads ranging from 70 m3/ha to more than 300 m3/ha, with a mean value of 178 m3/ha: both the range and the mean value are consistent with field data from streams with similar riparian forest types and climate. The model also predicts an LW jam spacing that is consistent with field data. Furthermore, our modeling results demonstrate that the high spatial and temporal variability in sediment storage, sediment transport, and channel morphology associated with LW-dominated streams occurs only when LW pieces interact and form jams. Model runs that do not include jam formation are much less variable. These results suggest that river restoration efforts using engineered LW pieces that are fixed in place and not permitted to interact will be less successful at restoring the geomorphic processes responsible for producing diverse, productive

  8. Models comparative study for heat storage in fixed beds; Estudo comparativo de modelos para armazenamento de calor em leitos fixos

    Energy Technology Data Exchange (ETDEWEB)

    Stuginski Junior, Rubens

    1991-07-01

    This work presents comparative results of a numerical investigation of four possible models for the prediction of thermal performance of fixed bed storage units and their thermal design. These models includes Schumann's model, the radial dispersion model, a model that include both axial heat conduction in the fluid phase and admits thermal gradient in the solids particles and finally a two dimensional single phase model. For each of these models a computer code was written and tested to evaluate the computing time of same data and analyze any other computational problems. The tests of thermal performance included particle size, porosity, particle material, flow rate, inlet temperature and heat losses form tank walls and extremities. Dynamics behaviour of the storage units due to transient variation in either flow rate or inlet temperature was also investigated. The results presented include temperature gradients, pressure drop and heat storage. The results obtained are very useful for analysis and design of fixed bed storage units. (author)

  9. Application of multivariate storage model to quantify trends in seasonally frozen soil

    Directory of Open Access Journals (Sweden)

    Woody Jonathan

    2016-06-01

    Full Text Available This article presents a study of the ground thermal regime recorded at 11 stations in the North Dakota Agricultural Network. Particular focus is placed on detecting trends in the annual ground freeze process portion of the ground thermal regime’s daily temperature signature. A multivariate storage model from queuing theory is fit to a quantity of estimated daily depths of frozen soil. Statistical inference on a trend parameter is obtained by minimizing a weighted sum of squares of a sequence of daily one-step-ahead predictions. Standard errors for the trend estimates are presented. It is shown that the daily quantity of frozen ground experienced at these 11 sites exhibited a negative trend over the observation period.

  10. Application of multivariate storage model to quantify trends in seasonally frozen soil

    Science.gov (United States)

    Woody, Jonathan; Wang, Yan; Dyer, Jamie

    2016-06-01

    This article presents a study of the ground thermal regime recorded at 11 stations in the North Dakota Agricultural Network. Particular focus is placed on detecting trends in the annual ground freeze process portion of the ground thermal regime's daily temperature signature. A multivariate storage model from queuing theory is fit to a quantity of estimated daily depths of frozen soil. Statistical inference on a trend parameter is obtained by minimizing a weighted sum of squares of a sequence of daily one-step-ahead predictions. Standard errors for the trend estimates are presented. It is shown that the daily quantity of frozen ground experienced at these 11 sites exhibited a negative trend over the observation period.

  11. 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.

  12. On the Modeling of Bank Storage in a Groundwater Model: The April, 1983, Flood Event in the Neuwieder Becken (Middle Rhine

    Directory of Open Access Journals (Sweden)

    Bernhard P. J. Becker

    2015-03-01

    Full Text Available For predictive numerical simulations of subsurface floods (groundwater head rise due to high water in a contiguous river, it is important to know how to represent the bank storage process in a numerical groundwater model. Whilst leakage approaches are frequently used for modeling bank storage, another option is the application of a head boundary condition. In order to get a better understanding of the bank storage process, we analyze the bank storage event in the Neuwieder Becken (Middle Rhine in April 1983, which has been reported by Ubell (1987. We found the leakage function to be nonlinear and hysteretic. The evaluation of different model variants for Ubell’s bank storage event shows that both a head boundary condition and a leakage boundary condition are appropriate modeling approaches. For practical reasons, the leakage boundary condition is preferred. A linear leakage function represents the bank storage process for the analyzed event sufficiently. A hysteretic course of the leakage function can be achieved in a three-dimensional groundwater model by layering the hydraulic soil properties in the vicinity of the bank.

  13. User-Friendly Predictive Modeling of Greenhouse Gas (GHG) Fluxes and Carbon Storage in Tidal Wetlands

    Science.gov (United States)

    Ishtiaq, K. S.; Abdul-Aziz, O. I.

    2015-12-01

    We developed user-friendly empirical models to predict instantaneous fluxes of CO2 and CH4 from coastal wetlands based on a small set of dominant hydro-climatic and environmental drivers (e.g., photosynthetically active radiation, soil temperature, water depth, and soil salinity). The dominant predictor variables were systematically identified by applying a robust data-analytics framework on a wide range of possible environmental variables driving wetland greenhouse gas (GHG) fluxes. The method comprised of a multi-layered data-analytics framework, including Pearson correlation analysis, explanatory principal component and factor analyses, and partial least squares regression modeling. The identified dominant predictors were finally utilized to develop power-law based non-linear regression models to predict CO2 and CH4 fluxes under different climatic, land use (nitrogen gradient), tidal hydrology and salinity conditions. Four different tidal wetlands of Waquoit Bay, MA were considered as the case study sites to identify the dominant drivers and evaluate model performance. The study sites were dominated by native Spartina Alterniflora and characterized by frequent flooding and high saline conditions. The model estimated the potential net ecosystem carbon balance (NECB) both in gC/m2 and metric tonC/hectare by up-scaling the instantaneous predicted fluxes to the growing season and accounting for the lateral C flux exchanges between the wetlands and estuary. The entire model was presented in a single Excel spreadsheet as a user-friendly ecological engineering tool. The model can aid the development of appropriate GHG offset protocols for setting monitoring plans for tidal wetland restoration and maintenance projects. The model can also be used to estimate wetland GHG fluxes and potential carbon storage under various IPCC climate change and sea level rise scenarios; facilitating an appropriate management of carbon stocks in tidal wetlands and their incorporation into a

  14. Stream Tracer Integrity: Comparative Analyses of Rhodamine-WT and Sodium Chloride through Transient Storage Modeling

    Science.gov (United States)

    Smull, E. M.; Wlostowski, A. N.; Gooseff, M. N.; Bowden, W. B.; Wollheim, W. M.

    2013-12-01

    Solute transport in natural channels describes the transport of water and dissolved matter through a river reach of interest. Conservative tracers allow us to label a parcel of stream water, such that we can track its movement downstream through space and time. A transient storage model (TSM) can be fit to the breakthrough curve (BTC) following a stream tracer experiment, as a way to quantify advection, dispersion, and transient storage processes. Arctic streams and rivers, in particular, are continuously underlain by permafrost, which provides for a simplified surface water-groundwater exchange. Sodium chloride (NaCl) and Rhodamine-WT (RWT) are widely used tracers, and differences between the two in conservative behavior and detection limits have been noted in small-scale field and laboratory studies. This study seeks to further this understanding by applying the OTIS model to NaCl and RWT BTC data from a field study on the Kuparuk River, Alaska, at varying flow rates. There are two main questions to be answered: 1) Do differences in NaCl and RWT manifest in OTIS parameter values? 2) Are the OTIS model results reliable for NaCl, RWT, or both? Fieldwork was performed in the summer of 2012 on the Kuparuk River, and modeling was performed using a modified OTIS framework, which provided for parameter optimization and further global sensitivity analyses. The results of this study will contribute to the greater body of literature surrounding Arctic stream hydrology, and it will assist in methodology for future tracer field studies. Additionally, the modeling work will provide an analysis for OTIS parameter identifiability, and assess stream tracer integrity (i.e. how well the BTC data represents the system) and its relation to TSM performance (i.e. how well the TSM can find a unique fit to the BTC data). The quantitative tools used can be applied to other solute transport studies, to better understand potential deviations in model outcome due to stream tracer choice and

  15. A mouse model for fucosidosis recapitulates storage pathology and neurological features of the milder form of the human disease.

    Science.gov (United States)

    Wolf, Heike; Damme, Markus; Stroobants, Stijn; D'Hooge, Rudi; Beck, Hans Christian; Hermans-Borgmeyer, Irm; Lüllmann-Rauch, Renate; Dierks, Thomas; Lübke, Torben

    2016-09-01

    Fucosidosis is a rare lysosomal storage disorder caused by the inherited deficiency of the lysosomal hydrolase α-L-fucosidase, which leads to an impaired degradation of fucosylated glycoconjugates. Here, we report the generation of a fucosidosis mouse model, in which the gene for lysosomal α-L-fucosidase (Fuca1) was disrupted by gene targeting. Homozygous knockout mice completely lack α-L-fucosidase activity in all tested organs leading to highly elevated amounts of the core-fucosylated glycoasparagine Fuc(α1,6)-GlcNAc(β1-N)-Asn and, to a lesser extent, other fucosylated glycoasparagines, which all were also partially excreted in urine. Lysosomal storage pathology was observed in many visceral organs, such as in the liver, kidney, spleen and bladder, as well as in the central nervous system (CNS). On the cellular level, storage was characterized by membrane-limited cytoplasmic vacuoles primarily containing water-soluble storage material. In the CNS, cellular alterations included enlargement of the lysosomal compartment in various cell types, accumulation of secondary storage material and neuroinflammation, as well as a progressive loss of Purkinje cells combined with astrogliosis leading to psychomotor and memory deficits. Our results demonstrate that this new fucosidosis mouse model resembles the human disease and thus will help to unravel underlying pathological processes. Moreover, this model could be utilized to establish diagnostic and therapeutic strategies for fucosidosis.

  16. A mouse model for fucosidosis recapitulates storage pathology and neurological features of the milder form of the human disease

    Directory of Open Access Journals (Sweden)

    Heike Wolf

    2016-09-01

    Full Text Available Fucosidosis is a rare lysosomal storage disorder caused by the inherited deficiency of the lysosomal hydrolase α-L-fucosidase, which leads to an impaired degradation of fucosylated glycoconjugates. Here, we report the generation of a fucosidosis mouse model, in which the gene for lysosomal α-L-fucosidase (Fuca1 was disrupted by gene targeting. Homozygous knockout mice completely lack α-L-fucosidase activity in all tested organs leading to highly elevated amounts of the core-fucosylated glycoasparagine Fuc(α1,6-GlcNAc(β1-N-Asn and, to a lesser extent, other fucosylated glycoasparagines, which all were also partially excreted in urine. Lysosomal storage pathology was observed in many visceral organs, such as in the liver, kidney, spleen and bladder, as well as in the central nervous system (CNS. On the cellular level, storage was characterized by membrane-limited cytoplasmic vacuoles primarily containing water-soluble storage material. In the CNS, cellular alterations included enlargement of the lysosomal compartment in various cell types, accumulation of secondary storage material and neuroinflammation, as well as a progressive loss of Purkinje cells combined with astrogliosis leading to psychomotor and memory deficits. Our results demonstrate that this new fucosidosis mouse model resembles the human disease and thus will help to unravel underlying pathological processes. Moreover, this model could be utilized to establish diagnostic and therapeutic strategies for fucosidosis.

  17. A mouse model for fucosidosis recapitulates storage pathology and neurological features of the milder form of the human disease

    Science.gov (United States)

    Wolf, Heike; Stroobants, Stijn; D'Hooge, Rudi; Hermans-Borgmeyer, Irm; Lüllmann-Rauch, Renate; Dierks, Thomas; Lübke, Torben

    2016-01-01

    ABSTRACT Fucosidosis is a rare lysosomal storage disorder caused by the inherited deficiency of the lysosomal hydrolase α-L-fucosidase, which leads to an impaired degradation of fucosylated glycoconjugates. Here, we report the generation of a fucosidosis mouse model, in which the gene for lysosomal α-L-fucosidase (Fuca1) was disrupted by gene targeting. Homozygous knockout mice completely lack α-L-fucosidase activity in all tested organs leading to highly elevated amounts of the core-fucosylated glycoasparagine Fuc(α1,6)-GlcNAc(β1-N)-Asn and, to a lesser extent, other fucosylated glycoasparagines, which all were also partially excreted in urine. Lysosomal storage pathology was observed in many visceral organs, such as in the liver, kidney, spleen and bladder, as well as in the central nervous system (CNS). On the cellular level, storage was characterized by membrane-limited cytoplasmic vacuoles primarily containing water-soluble storage material. In the CNS, cellular alterations included enlargement of the lysosomal compartment in various cell types, accumulation of secondary storage material and neuroinflammation, as well as a progressive loss of Purkinje cells combined with astrogliosis leading to psychomotor and memory deficits. Our results demonstrate that this new fucosidosis mouse model resembles the human disease and thus will help to unravel underlying pathological processes. Moreover, this model could be utilized to establish diagnostic and therapeutic strategies for fucosidosis. PMID:27491075

  18. Thermodynamic modeling of hydrogen storage capacity in Mg-Na alloys.

    Science.gov (United States)

    Abdessameud, S; Mezbahul-Islam, M; Medraj, M

    2014-01-01

    Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems.

  19. Design, Modeling and Control of Magnetic Bearings for a Ring-Type Flywheel Energy Storage System

    Directory of Open Access Journals (Sweden)

    Chow-Shing Toh

    2016-12-01

    Full Text Available This study is concerned with the magnetic force models of magnetic bearing in a flywheel energy storage system (FESS. The magnetic bearing is of hybrid type, with axial passive magnetic bearing (PMB and radial hybrid magnetic bearing (HMB. For the PMB, a pair of ring-type Halbach arrays of permanent magnets are arranged vertically to support the rotor weight. For the HMB, a set of ring-type Halbach array is placed on the rotor side, which corresponds to coil sets on the stator side. The HMB can produce both attraction and repulsion forces on the radial direction, depending on the direction of the coil currents. It is found that the ring-type configuration and the differential winding scheme for coil sets can yield linear magnetic force models for both PMB and HMB. Based on the obtained magnetic force model, an integral sliding mode controller is designed for the stable rotor levitation in the radial direction. The experimental results show that the rotor can be stabilized to the bearing center, verifying the accuracy of the magnetic force models and effectiveness of the levitation controller.

  20. Modeling, Design and Simulation of Stand-Alone Photovoltaic Power Systems with Battery Storage

    Directory of Open Access Journals (Sweden)

    Abd Essalam BADOUD

    2013-06-01

    Full Text Available Stand alone renewable energy based on photovoltaic systems accompanied with battery storage system are beginning to play an important role over the world to supply power to remote areas. The objective of the study reported in this paper is to elaborate and design a bond graphs model for sizing stand-alone domestic solar photovoltaic electricity systems and simulating the performance of the systems in a tropical climate. The systems modelled consist of an array of PV modules, a lead-acid battery, and a number of direct current appliances. This paper proposes the combination of lead acid battery system with a typical stand alone photovoltaic energy system under variable loads. The main activities of this work purpose to establish library graphical models for each individual component of standalone photovoltaic system. Control strategy has been considered to achieve permanent power supply to the load via photovoltaic/battery based on the power available from the sun. The complete model was simulated under two testing including sunny and cloudy conditions. Simulation of the system using Symbols software was performed and the results of simulation show the superior stable control system and high efficiency. These results have been contrasted with real measured data from a measurement campaign plant carried on electrical engineering laboratory of Grenoble using various interconnection schemes are presented.