WorldWideScience

Sample records for b-l model naturally

  1. The B - L scotogenic models for Dirac neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weijian [North China Electric Power University, Department of Physics, Baoding (China); Wang, Ruihong [Hebei Agricultural University, College of Information Science and Technology, Baoding (China); Han, Zhi-Long [University of Jinan, School of Physics and Technology, Jinan, Shandong (China); Han, Jin-Zhong [Zhoukou Normal University, School of Physics and Telecommunications Engineering, Zhoukou, Henan (China)

    2017-12-15

    We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of U(1){sub B-L} extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by the anomaly free condition and the new particles may have exotic B - L charges so that the direct SM Yukawa mass term anti ν{sub L}ν{sub R}φ{sup 0} and the Majorana mass term (m{sub N}/2)ν{sub R}{sup C}ν{sub R} are naturally forbidden. After the spontaneous breaking of the U(1){sub B-L} symmetry, the discrete Z{sub 2} or Z{sub 3} symmetry appears as the residual symmetry and gives rise to the stability of intermediate fields as DM candidates. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed. (orig.)

  2. The B-L scotogenic models for Dirac neutrino masses

    Science.gov (United States)

    Wang, Weijian; Wang, Ruihong; Han, Zhi-Long; Han, Jin-Zhong

    2017-12-01

    We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of U(1)_{B-L} extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by the anomaly free condition and the new particles may have exotic B-L charges so that the direct SM Yukawa mass term \\bar{ν }_Lν _R\\overline{φ ^0} and the Majorana mass term (m_N/2)\\overline{ν _R^C}ν _R are naturally forbidden. After the spontaneous breaking of the U(1)_{B-L} symmetry, the discrete Z2 or Z3 symmetry appears as the residual symmetry and gives rise to the stability of intermediate fields as DM candidates. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed.

  3. Asymmetric Gepner models III. B-L lifting

    Energy Technology Data Exchange (ETDEWEB)

    Gato-Rivera, B. [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands); Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); Schellekens, A.N., E-mail: t58@nikhef.n [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands); Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); IMAPP, Radboud Universiteit, Nijmegen (Netherlands)

    2011-06-21

    In the same spirit as heterotic weight lifting, B-L lifting is a way of replacing the superfluous and ubiquitous U(1){sub B-L} with something else with the same modular properties, but different conformal weights and ground state dimensions. This method works in principle for all variants of (2,2) constructions, such as orbifolds, Calabi-Yau manifolds, free bosons and fermions and Gepner models, since it only modifies the universal SO(10)xE{sub 8} part of the CFT. However, it can only yield chiral spectra if the 'internal' sector of the theory provides a simple current of order 5. Here we apply this new method to Gepner models. Including exceptional invariants, 86 of them have the required order 5 simple current, and 69 of these yield chiral spectra. Three family spectra occur abundantly.

  4. Electroweak vacuum stability in classically conformal B - L extension of the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Das, Arindam; Okada, Nobuchika; Papapietro, Nathan [University of Alabama, Department of Physics and Astronomy, Alabama (United States)

    2017-02-15

    We consider the minimal U(1){sub B-L} extension of the standard model (SM) with the classically conformal invariance, where an anomaly-free U(1){sub B-L} gauge symmetry is introduced along with three generations of right-handed neutrinos and a U(1){sub B-L} Higgs field. Because of the classically conformal symmetry, all dimensional parameters are forbidden. The B - L gauge symmetry is radiatively broken through the Coleman-Weinberg mechanism, generating the mass for the U(1){sub B-L} gauge boson (Z{sup '} boson) and the right-handed neutrinos. Through a small negative coupling between the SM Higgs doublet and the B - L Higgs field, the negative mass term for the SM Higgs doublet is generated and the electroweak symmetry is broken. In this model context, we investigate the electroweak vacuum instability problem in the SM. It is well known that in the classically conformal U(1){sub B-L} extension of the SM, the electroweak vacuum remains unstable in the renormalization group analysis at the one-loop level. In this paper, we extend the analysis to the two-loop level, and perform parameter scans. We identify a parameter region which not only solve the vacuum instability problem, but also satisfy the recent ATLAS and CMS bounds from search for Z{sup '} boson resonance at the LHC Run-2. Considering self-energy corrections to the SM Higgs doublet through the right-handed neutrinos and the Z{sup '} boson, we derive the naturalness bound on the model parameters to realize the electroweak scale without fine-tunings. (orig.)

  5. Leptogenesis constraints on B - L breaking Higgs boson in TeV scale seesaw models

    Science.gov (United States)

    Dev, P. S. Bhupal; Mohapatra, Rabindra N.; Zhang, Yongchao

    2018-03-01

    In the type-I seesaw mechanism for neutrino masses, there exists a B - L symmetry, whose breaking leads to the lepton number violating mass of the heavy Majorana neutrinos. This would imply the existence of a new neutral scalar associated with the B - L symmetry breaking, analogous to the Higgs boson of the Standard Model. If in such models, the heavy neutrino decays are also responsible for the observed baryon asymmetry of the universe via the leptogenesis mechanism, the new seesaw scalar interactions with the heavy neutrinos will induce additional dilution terms for the heavy neutrino and lepton number densities. We make a detailed study of this dilution effect on the lepton asymmetry in three generic classes of seesaw models with TeV-scale B - L symmetry breaking, namely, in an effective theory framework and in scenarios with global or local U(1) B- L symmetry. We find that requiring successful leptogenesis imposes stringent constraints on the mass and couplings of the new scalar in all three cases, especially when it is lighter than the heavy neutrinos. We also discuss the implications of these new constraints and prospects of testing leptogenesis in presence of seesaw scalars at colliders.

  6. NLO+NLL collider bounds, Dirac fermion and scalar dark matter in the B-L model

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, Michael [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Theoretische Physik, Muenster (Germany); Lyonnet, Florian [Southern Methodist University, Dallas, TX (United States); Queiroz, Farinaldo S. [Max-Planck-Institut fuer Kernphysik, Particle and Astroparticle Physics Division, Heidelberg (Germany)

    2017-05-15

    Baryon and lepton numbers being accidental global symmetries of the Standard Model (SM), it is natural to promote them to local symmetries. However, to preserve anomaly-freedom, only combinations of B-L are viable. In this spirit, we investigate possible dark matter realizations in the context of the U(1){sub B-L} model: (i) Dirac fermion with unbroken B-L; (ii) Dirac fermion with broken B-L; (iii) scalar dark matter; (iv) two-component dark matter. We compute the relic abundance, direct and indirect detection observables and confront them with recent results from Planck, LUX-2016, and Fermi-LAT and prospects from XENON1T. In addition to the well-known LEP bound M{sub Z}{sup {sub '}}/g{sub BL} >or similar 7 TeV, we include often ignored LHC bounds using 13 TeV dilepton (dimuon + dielectron) data at next-to-leading order plus next-to-leading logarithmic accuracy. We show that, for gauge couplings smaller than 0.4, the LHC gives rise to the strongest collider limit. In particular, we find M{sub Z}{sup {sub '}}/g{sub BL} > 8.7 TeV for g{sub BL} = 0.3. We conclude that the NLO+NLL corrections improve the dilepton bounds on the Z{sup '} mass and that both dark matter candidates are only viable in the Z{sup '} resonance region, with the parameter space for scalar dark matter being fully probed by XENON1T. Lastly, we show that one can successfully have a minimal two-component dark matter model. (orig.)

  7. Neutrino mass, leptogenesis and FIMP dark matter in a U(1){sub B-L} model

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Anirban; Khan, Sarif [Harish-Chandra Research Institute, Allahabad (India); Homi Bhabha National Institute, Training School Complex, Mumbai (India); Choubey, Sandhya [Harish-Chandra Research Institute, Allahabad (India); Homi Bhabha National Institute, Training School Complex, Mumbai (India); AlbaNova University Center, Department of Theoretical Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm (Sweden)

    2017-12-15

    The Standard Model (SM) is inadequate to explain the origin of tiny neutrino masses, the dark matter (DM) relic abundance and the baryon asymmetry of the Universe. In this work, to address all three puzzles, we extend the SM by a local U(1){sub B-L} gauge symmetry, three right-handed (RH) neutrinos for the cancellation of gauge anomalies and two complex scalars having non-zero U(1){sub B-L} charges. All the newly added particles become massive after the breaking of the U(1){sub B-L} symmetry by the vacuum expectation value (VEV) of one of the scalar fields φ{sub H}. The other scalar field, φ{sub DM}, which does not have any VEV, becomes automatically stable and can be a viable DM candidate. Neutrino masses are generated using the Type-I seesaw mechanism, while the required lepton asymmetry to reproduce the observed baryon asymmetry can be attained from the CP violating out of equilibrium decays of the RH neutrinos in TeV scale. More importantly within this framework, we study in detail the production of DM via the freeze-in mechanism considering all possible annihilation and decay processes. Finally, we find a situation when DM is dominantly produced from the annihilation of the RH neutrinos, which are at the same time also responsible for neutrino mass generation and leptogenesis. (orig.)

  8. Neutrino mass, leptogenesis and FIMP dark matter in a U(1)_{B-L} model

    Science.gov (United States)

    Biswas, Anirban; Choubey, Sandhya; Khan, Sarif

    2017-12-01

    The Standard Model (SM) is inadequate to explain the origin of tiny neutrino masses, the dark matter (DM) relic abundance and the baryon asymmetry of the Universe. In this work, to address all three puzzles, we extend the SM by a local U(1)_{B-L} gauge symmetry, three right-handed (RH) neutrinos for the cancellation of gauge anomalies and two complex scalars having non-zero U(1)_{B-L} charges. All the newly added particles become massive after the breaking of the U(1)_{B-L} symmetry by the vacuum expectation value (VEV) of one of the scalar fields φ _H. The other scalar field, φ _DM, which does not have any VEV, becomes automatically stable and can be a viable DM candidate. Neutrino masses are generated using the Type-I seesaw mechanism, while the required lepton asymmetry to reproduce the observed baryon asymmetry can be attained from the CP violating out of equilibrium decays of the RH neutrinos in TeV scale. More importantly within this framework, we study in detail the production of DM via the freeze-in mechanism considering all possible annihilation and decay processes. Finally, we find a situation when DM is dominantly produced from the annihilation of the RH neutrinos, which are at the same time also responsible for neutrino mass generation and leptogenesis.

  9. Neutrinophilic two Higgs doublet model with dark matter under an alternative U(1)_{B-L} gauge symmetry

    Science.gov (United States)

    Nomura, Takaaki; Okada, Hiroshi

    2018-03-01

    We propose a Dirac type active neutrino with rank two mass matrix and a Majorana fermion dark matter candidate with an alternative local U(1)_{B-L} extension of neutrinophilic two Higgs doublet model. Our dark matter candidate can be stabilized due to charge assignment under the gauge symmetry without imposing extra discrete Z_2 symmetry and the relic density is obtained from an Z' boson exchanging process. Taking into account collider constraints on the Z' boson mass and coupling, we estimate the relic density.

  10. Non-resonant leptogenesis in seesaw models with an almost conserved B - L

    Energy Technology Data Exchange (ETDEWEB)

    Racker, J., E-mail: racker@ific.uv.es [Universidad de Valencia-CSIC, Depto. de Fisica Teorica and IFIC (Spain)

    2013-03-15

    We review the motivations and some results on leptogenesis in seesaw models with an almost conserved lepton number. The paper is based on a talk given at the 5th International Symposium on Symmetries in Subatomic Physics, SSP2012.

  11. ɛ '/ ɛ anomaly and neutron EDM in SU(2) L × SU(2) R × U(1) B- L model with charge symmetry

    Science.gov (United States)

    Haba, Naoyuki; Umeeda, Hiroyuki; Yamada, Toshifumi

    2018-05-01

    The Standard Model prediction for ɛ '/ ɛ based on recent lattice QCD results exhibits a tension with the experimental data. We solve this tension through W R + gauge boson exchange in the SU(2) L × SU(2) R × U(1) B- L model with `charge symmetry', whose theoretical motivation is to attribute the chiral structure of the Standard Model to the spontaneous breaking of SU(2) R × U(1) B- L gauge group and charge symmetry. We show that {M_W}{_R}study a correlation between ɛ ' /ɛ and the neutron EDM. We confirm that the model can solve the ɛ ' /ɛ anomaly without conflicting the current bound on the neutron EDM, and further reveal that almost all parameter regions in which the ɛ ' /ɛ anomaly is explained will be covered by future neutron EDM searches, which leads us to anticipate the discovery of the neutron EDM.

  12. Can blueshifted Agn spectra explain B L Lac objects

    International Nuclear Information System (INIS)

    Basu, D.

    2009-01-01

    B L Lac spectra are almost completely devoid of any emission line, and absorption features are often present based on which redshifts are estimated. Several models have been proposed to explain the spectra, including the unification scheme currently most popular among astronomers. However, there appear to be ambiguities, uncertainties and contradictory results in this model, and many questions remain unanswered. Also, it involves the process of artificially enhancing the continuum to be concentrated to a high level, by the relativistically beaming jet action, in order to submerge the emission lines, partly or completely, to make them appear weak or invisible. Additionally, the sample based on which B L Lac objects have been included in the unification scheme is rather small to be statistically viable. In this context, we present an alternative and much simpler interpretation of the observed spectra of B L Lac objects, both emission and absorption, as blueshifted lines in Agn. Original spectra of fifty six objects available in the current literature are re-analyzed. Nine of these show only a single weak emission line and no absorption feature, while thirty five exhibit no emission feature but several absorption lines, and another twelve show more than one emission line and, in some cases, several absorption lines. It is demonstrated that emission lines in most B L Lac objects are blueshifted out of the visible region, and, hence, not seen at all. Emission lines, when seen, and absorption lines, are blueshifted and are identified with search lines of longer wavelengths that are naturally weak. Blue shifts, in emission and absorption features, are determined for all objects. Various considerations lead to the conclusion that the blue shift interpretation of B L Lac spectra is superior to and more important than the redshift interpretation. A possible explanation of observed blue shifts is presented in the scenario of the ejection process, a well-recognized mechanism

  13. B-L mediated SUSY breaking with radiative B-L symmetry breaking

    International Nuclear Information System (INIS)

    Kikuchi, Tatsuru; Kubo, Takayuki

    2008-01-01

    We explore a mechanism of radiative B-L symmetry breaking in analogous to the radiative electroweak symmetry breaking. The breaking scale of B-L symmetry is related to the neutrino masses through the see-saw mechanism. Once we incorporate the U(1) B-L gauge symmetry in SUSY models, the U(1) B-L gaugino, Z-tilde B-L appears, and it can mediate the SUSY breaking (Z-prime mediated SUSY breaking) at around the scale of 10 6 GeV. Then we find a links between the neutrino mass (more precisly the see-saw or B-L scale of order 10 6 GeV) and the Z-prime mediated SUSY breaking scale. It is also very interesting that the gluino at the weak scale becomes relatively light, and almost compressed mass spectra for the gaugino sector can be realized in this scenario, which is very interesting in scope of the LHC.

  14. The B-L phase transition. Implications for cosmology and neutrinos

    International Nuclear Information System (INIS)

    Schmitz, Kai

    2012-07-01

    very heavy gravitinos, which are motivated by hints for the Higgs boson at the LHC. We find that the nonthermal production of pure wino or higgsino LSPs, i.e. weakly interacting massive particles (WIMPs), in heavy gravitino decays can account for the observed amount of dark matter, while simultaneously fulfilling the constraints imposed by primordial nucleosynthesis and leptogenesis, within a range of LSP, gravitino and neutrino masses. Besides its cosmological implications, the spontaneous breaking of B-L also naturally explains the small observed neutrino masses via the seesaw mechanism. Upon the seesaw model we impose a flavour structure of the Froggatt-Nielson type which, together with the known neutrino data, allows us to strongly contrain yet undetermined neutrino observables.

  15. The B-L phase transition. Implications for cosmology and neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Kai

    2012-07-15

    very heavy gravitinos, which are motivated by hints for the Higgs boson at the LHC. We find that the nonthermal production of pure wino or higgsino LSPs, i.e. weakly interacting massive particles (WIMPs), in heavy gravitino decays can account for the observed amount of dark matter, while simultaneously fulfilling the constraints imposed by primordial nucleosynthesis and leptogenesis, within a range of LSP, gravitino and neutrino masses. Besides its cosmological implications, the spontaneous breaking of B-L also naturally explains the small observed neutrino masses via the seesaw mechanism. Upon the seesaw model we impose a flavour structure of the Froggatt-Nielson type which, together with the known neutrino data, allows us to strongly contrain yet undetermined neutrino observables.

  16. Modeling Natural Selection

    Science.gov (United States)

    Bogiages, Christopher A.; Lotter, Christine

    2011-01-01

    In their research, scientists generate, test, and modify scientific models. These models can be shared with others and demonstrate a scientist's understanding of how the natural world works. Similarly, students can generate and modify models to gain a better understanding of the content, process, and nature of science (Kenyon, Schwarz, and Hug…

  17. SU(5) without SU(5): why B-L is conserved and baryon number not in unified models of quarks and leptons

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1980-09-01

    Quark-lepton unification is examined without assuming higher symmetries on more general gauge theories. In particular, properties are sought which are generally attributed to SU(5) models which are already present without the assumption of SU(5)

  18. The gravitational wave spectrum from cosmological B-L breaking

    International Nuclear Information System (INIS)

    Buchmueller, W.; Domcke, V.; Kamada, K.; Schmitz, K.

    2013-05-01

    Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying Ω GW h 2 ∝10 -13 -10 -8 , much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eLISA, advanced LIGO and BBO/DECIGO will reach the sensitivity needed to test the predictions from cosmological B-L breaking.

  19. The gravitational wave spectrum from cosmological B-L breaking

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Domcke, V.; Kamada, K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Schmitz, K. [Tokyo Univ., Kashiwa (Japan). Kavli IPMU (WPI)

    2013-05-15

    Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying {Omega}{sub GW}h{sup 2}{proportional_to}10{sup -13}-10{sup -8}, much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eLISA, advanced LIGO and BBO/DECIGO will reach the sensitivity needed to test the predictions from cosmological B-L breaking.

  20. Majorana dark matter with B+L gauge symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Wei [Amherst Center for Fundamental Interactions, Department of Physics,University of Massachusetts-Amherst,Amherst, MA 01003 United States (United States); Center for Advanced Quantum Studies,Department of Physics, Beijing Normal University,Beijing, 100875 (China); Guo, Huai-Ke [Amherst Center for Fundamental Interactions, Department of Physics,University of Massachusetts-Amherst,Amherst, MA 01003 United States (United States); Zhang, Yongchao [Service de Physique Théorique, Université Libre de Bruxelles,Boulevard du Triomphe, CP225, 1050 Brussels (Belgium)

    2017-04-07

    We present a new model that extends the Standard Model (SM) with the local B+L symmetry, and point out that the lightest new fermion ζ, introduced to cancel anomalies and stabilized automatically by the B+L symmetry, can serve as the cold dark matter candidate. We study constraints on the model from Higgs measurements, electroweak precision measurements as well as the relic density and direct detections of the dark matter. Numerical results reveal that the pseudo-vector coupling of ζ with Z and the Yukawa coupling with the SM Higgs are highly constrained by the latest results of LUX, while there are viable parameter space that could satisfy all the constraints and give testable predictions.

  1. B-L violating supersymmetric couplings

    International Nuclear Information System (INIS)

    Ramond, P.

    1983-01-01

    We consider two problems: one is the possible effect of the breaking of Peccei-Quinn symmetry on the inflationary universe scenario; the other is the remark that even the minimal supersymmetric SU 5 theory contains B-L violating couplings which give rise to neutrino masses and family-diagonal proton decay. However the strength of these couplings is limited by the gauge hierarchy

  2. Natural language modeling

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, J.K. [Sandia National Labs., Albuquerque, NM (United States)

    1997-11-01

    This seminar describes a process and methodology that uses structured natural language to enable the construction of precise information requirements directly from users, experts, and managers. The main focus of this natural language approach is to create the precise information requirements and to do it in such a way that the business and technical experts are fully accountable for the results. These requirements can then be implemented using appropriate tools and technology. This requirement set is also a universal learning tool because it has all of the knowledge that is needed to understand a particular process (e.g., expense vouchers, project management, budget reviews, tax, laws, machine function).

  3. Modelling: Nature and Use

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    Engineering of products and processes is increasingly “model-centric”. Models in their multitudinous forms are ubiquitous, being heavily used for a range of decision making activities across all life cycle phases. This chapter gives an overview of what is a model, the principal activities in the ...

  4. B+ L violation at colliders and new physics

    Science.gov (United States)

    Cerdeño, David G.; Reimitz, Peter; Sakurai, Kazuki; Tamarit, Carlos

    2018-04-01

    Chiral electroweak anomalies predict baryon ( B) and lepton ( L) violating fermion interactions, which can be dressed with large numbers of Higgs and gauge bosons. The estimation of the total B + L-violating rate from an initial two-particle state — potentially observable at colliders — has been the subject of an intense discussion, mainly centered on the resummation of boson emission, which is believed to contribute to the cross-section with an exponential function of the energy, yet with an exponent (the "holy-grail" function) which is not fully known in the energy range of interest. In this article we focus instead on the effect of fermions beyond the Standard-Model (SM) in the polynomial contributions to the rate. It is shown that B + L processes involving the new fermions have a polynomial contribution that can be several orders of magnitude greater than in the SM, for high centre-of-mass energies and light enough masses. We also present calculations that hint at a simple dependence of the holy grail function on the heavy fermion masses. Thus, if anomalous B + L violating interactions are ever detected at high-energy colliders, they could be associated with new physics.

  5. Chaotic hybrid inflation with a gauged B -L

    Science.gov (United States)

    Carpenter, Linda M.; Raby, Stuart

    2014-11-01

    In this paper we present a novel formulation of chaotic hybrid inflation in supergravity. The model includes a waterfall field which spontaneously breaks a gauged U1 (B- L) at a GUT scale. This allows for the possibility of future model building which includes the standard formulation of baryogenesis via leptogenesis with the waterfall field decaying into right-handed neutrinos. We have not considered the following issues in this short paper, i.e. supersymmetry breaking, dark matter or the gravitino or moduli problems. Our focus is on showing the compatibility of the present model with Planck, WMAP and Bicep2 data.

  6. A natural human hand model

    NARCIS (Netherlands)

    Van Nierop, O.A.; Van der Helm, A.; Overbeeke, K.J.; Djajadiningrat, T.J.P.

    2007-01-01

    We present a skeletal linked model of the human hand that has natural motion. We show how this can be achieved by introducing a new biology-based joint axis that simulates natural joint motion and a set of constraints that reduce an estimated 150 possible motions to twelve. The model is based on

  7. Neutrino masses in the minimal gauged (B -L ) supersymmetry

    Science.gov (United States)

    Yan, Yu-Li; Feng, Tai-Fu; Yang, Jin-Lei; Zhang, Hai-Bin; Zhao, Shu-Min; Zhu, Rong-Fei

    2018-03-01

    We present the radiative corrections to neutrino masses in a minimal supersymmetric extension of the standard model with local U (1 )B -L symmetry. At tree level, three tiny active neutrinos and two nearly massless sterile neutrinos can be obtained through the seesaw mechanism. Considering the one-loop corrections to the neutrino masses, the numerical results indicate that two sterile neutrinos obtain KeV masses and the small active-sterile neutrino mixing angles. The lighter sterile neutrino is a very interesting dark matter candidate in cosmology. Meanwhile, the active neutrinos mixing angles and mass squared differences agree with present experimental data.

  8. A natural Poincare gauge model

    International Nuclear Information System (INIS)

    Aldrovandi, R.; Pereira, J.G.

    1985-01-01

    A natural candidate model for a gauge theory for the Poincare group is discussed. It satisfies the usual electric-magnetic symmetry of gauge models and is a contraction of a gauge model for the De Sitter group. Its field equations are just the Yang-Mills equations for the Poincare group. It is shown that these equations do not follow from a Lagrangean. (Author) [pt

  9. Dialectical Model of Human Nature

    OpenAIRE

    Cachat, Jonathan

    2013-01-01

    The DMoHN is a graphical representation of my current understanding and conceptualization of human nature, in addition to embodying the guiding ethos of social neuroscience. The dialectic is a logic, or way of thinking that joins opposite elements together in a uniting fashion to create emergent attributes not present in the elements alone. The dialectical structure of this model explicitly links Culture and Biology within the human brain in order to convey the symbiotic and dynamic interacti...

  10. Natural SUSY dark matter model

    International Nuclear Information System (INIS)

    Mohanty, Subhendra; Rao, Soumya; Roy, D.P.

    2013-01-01

    The most natural region of cosmologically compatible dark matter relic density in terms of low fine-tuning in a minimal supersymmetric standard model with nonuniversal gaugino masses is the so called bulk annihilation region. We study this region in a simple and predictive SUSY- GUT model of nonuniversal gaugino masses, where the latter transform as a combination of singlet plus a nonsinglet representation of the GUTgroup SU(5). The model prediction for the direct dark matter detection rates is well below the present CDMS and XENON100 limits, but within the reach of a future 1Ton XENON experiment. The most interesting and robust model prediction is an indirect detection signal of hard positron events, which resembles closely the shape of the observed positron spectrum from the PAMELA experiment. (author)

  11. Mathematics in Nature Modeling Patterns in the Natural World

    CERN Document Server

    Adam, John A

    2011-01-01

    From rainbows, river meanders, and shadows to spider webs, honeycombs, and the markings on animal coats, the visible world is full of patterns that can be described mathematically. Examining such readily observable phenomena, this book introduces readers to the beauty of nature as revealed by mathematics and the beauty of mathematics as revealed in nature.Generously illustrated, written in an informal style, and replete with examples from everyday life, Mathematics in Nature is an excellent and undaunting introduction to the ideas and methods of mathematical modeling. It illustrates how mathem

  12. Neutrino masses, dark matter and leptogenesis with U(1) B - L gauge symmetry

    Science.gov (United States)

    Geng, Chao-Qiang; Okada, Hiroshi

    2018-06-01

    We propose a model with an U(1) B - L gauge symmetry, in which small neutrino masses, dark matter and the matter-antimatter asymmetry in the Universe can be simultaneously explained. In particular, the neutrino masses are generated radiatively, while the matter-antimatter asymmetry is led by the leptogenesis mechanism, at TeV scale. We also explore allowed regions of the model parameters and discuss some phenomenological effects, including lepton flavor violating processes.

  13. Mathematical models of natural gas consumption

    International Nuclear Information System (INIS)

    Sabo, Kristian; Scitovski, Rudolf; Vazler, Ivan; Zekic-Susac, Marijana

    2011-01-01

    In this paper we consider the problem of natural gas consumption hourly forecast on the basis of hourly movement of temperature and natural gas consumption in the preceding period. There are various methods and approaches for solving this problem in the literature. Some mathematical models with linear and nonlinear model functions relating to natural gas consumption forecast with the past natural gas consumption data, temperature data and temperature forecast data are mentioned. The methods are tested on concrete examples referring to temperature and natural gas consumption for the area of the city of Osijek (Croatia) from the beginning of the year 2008. The results show that most acceptable forecast is provided by mathematical models in which natural gas consumption and temperature are related explicitly.

  14. Description of the Lewin Natural Gas Model

    International Nuclear Information System (INIS)

    Kuuskraa, V.; Godec, M.

    1989-01-01

    This paper provides a brief description of the Lewin Natural Gas Model, shows how this model differs in key features from the other models participating in EMF-9, and describes how the different modeling scenarios analyzed in EMF-9 were implemented in the Lewin model. This background helps explain the key results that have been gained from applying the Lewin model to the EMF scenarios

  15. Natural analogues and radionuclide transport model validation

    International Nuclear Information System (INIS)

    Lever, D.A.

    1987-08-01

    In this paper, some possible roles for natural analogues are discussed from the point of view of those involved with the development of mathematical models for radionuclide transport and with the use of these models in repository safety assessments. The characteristic features of a safety assessment are outlined in order to address the questions of where natural analogues can be used to improve our understanding of the processes involved and where they can assist in validating the models that are used. Natural analogues have the potential to provide useful information about some critical processes, especially long-term chemical processes and migration rates. There is likely to be considerable uncertainty and ambiguity associated with the interpretation of natural analogues, and thus it is their general features which should be emphasized, and models with appropriate levels of sophistication should be used. Experience gained in modelling the Koongarra uranium deposit in northern Australia is drawn upon. (author)

  16. A Gambler's Model of Natural Selection.

    Science.gov (United States)

    Nolan, Michael J.; Ostrovsky, David S.

    1996-01-01

    Presents an activity that highlights the mechanism and power of natural selection. Allows students to think in terms of modeling a biological process and instills an appreciation for a mathematical approach to biological problems. (JRH)

  17. Asymptotically Free Natural Supersymmetric Twin Higgs Model

    Science.gov (United States)

    Badziak, Marcin; Harigaya, Keisuke

    2018-05-01

    Twin Higgs (TH) models explain the absence of new colored particles responsible for natural electroweak symmetry breaking (EWSB). All known ultraviolet completions of TH models require some nonperturbative dynamics below the Planck scale. We propose a supersymmetric model in which the TH mechanism is introduced by a new asymptotically free gauge interaction. The model features natural EWSB for squarks and gluino heavier than 2 TeV even if supersymmetry breaking is mediated around the Planck scale, and has interesting flavor phenomenology including the top quark decay into the Higgs boson and the up quark which may be discovered at the LHC.

  18. Spontaneous B-L breaking as the origin of the hot early universe

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Domcke, V.; Schmitz, K.

    2012-03-15

    The decay of a false vacuum of unbroken B-L symmetry is an intriguing and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase yields hybrid inflation, ending in tachyonic preheating. The dynamics of the B - L breaking Higgs field and thermal processes produce an abundance of heavy neutrinos whose decays generate entropy, baryon asymmetry and gravitino dark matter. We study the phase transition for the full supersymmetric Abelian Higgs model. For the subsequent reheating process we give a detailed time-resolved description of all particle abundances. The competition of cosmic expansion and entropy production leads to an intermediate period of constant 'reheating' temperature, during which baryon asymmetry and dark matter are produced. Consistency of hybrid inflation, leptogenesis and gravitino dark matter implies relations between neutrino parameters and superparticle masses, in particular a lower bound on the gravitino mass of 10 GeV.

  19. On modelling the market for natural gas

    International Nuclear Information System (INIS)

    Mathiesen, Lars

    2001-12-01

    Several features may separately or in combination influence conduct and performance of an industry, e.g. the numbers of sellers or buyers, the degree of economies of scale in production and distribution, the temporal and spatial dimensions, etc. Our main focus is on how to model market power. In particular, we demonstrate the rather different solutions obtained from the price-taking behavior versus the oligopolistic Coumot behavior. We also consider two approaches to model the transportation of natural gas. Finally, there is a brief review of previous modeling efforts of the European natural gas industry. (author)

  20. RECENT ADVANCES IN NATURALLY FRACTURED RESERVOIR MODELING

    OpenAIRE

    ORDOÑEZ, A; PEÑUELA, G; IDROBO, E. A; MEDINA, C. E

    2001-01-01

    Large amounts of oil reserves are contained in naturally fractured reservoirs. Most of these hydrocarbon volumes have been left behind because of the poor knowledge and/or description methodology of those reservoirs. This lack of knowledge has lead to the nonexistence of good quantitative models for this complicated type of reservoirs. The complexity of naturally fractured reservoirs causes the need for integration of all existing information at all scales (drilling, well logging, seismic, we...

  1. Neutral Naturalness from Orbifold Higgs Models

    Science.gov (United States)

    Craig, Nathaniel; Knapen, Simon; Longhi, Pietro

    2015-02-01

    We present a general class of natural theories in which the Higgs boson is a pseudo-Goldstone boson in an orbifolded gauge theory. The symmetry protecting the Higgs boson at low energies is an accidental global symmetry of the quadratic action, rather than a full continuous symmetry. The lightest degrees of freedom protecting the weak scale carry no standard model (SM) quantum numbers and interact with visible matter principally through the Higgs portal. This opens the door to the systematic study of "neutral naturalness": natural theories with SM-neutral states that are as yet untested by the LHC.

  2. Homophyly/Kinship Model: Naturally Evolving Networks

    Science.gov (United States)

    Li, Angsheng; Li, Jiankou; Pan, Yicheng; Yin, Xianchen; Yong, Xi

    2015-10-01

    It has been a challenge to understand the formation and roles of social groups or natural communities in the evolution of species, societies and real world networks. Here, we propose the hypothesis that homophyly/kinship is the intrinsic mechanism of natural communities, introduce the notion of the affinity exponent and propose the homophyly/kinship model of networks. We demonstrate that the networks of our model satisfy a number of topological, probabilistic and combinatorial properties and, in particular, that the robustness and stability of natural communities increase as the affinity exponent increases and that the reciprocity of the networks in our model decreases as the affinity exponent increases. We show that both homophyly/kinship and reciprocity are essential to the emergence of cooperation in evolutionary games and that the homophyly/kinship and reciprocity determined by the appropriate affinity exponent guarantee the emergence of cooperation in evolutionary games, verifying Darwin’s proposal that kinship and reciprocity are the means of individual fitness. We propose the new principle of structure entropy minimisation for detecting natural communities of networks and verify the functional module property and characteristic properties by a healthy tissue cell network, a citation network, some metabolic networks and a protein interaction network.

  3. Modeling natural regeneration biomass of Pinus stand

    Directory of Open Access Journals (Sweden)

    Rafael Cubas

    2016-09-01

    Full Text Available Reliable biomass data are very important in the evaluation of ecosystems, and help in understanding the contribution of forests in climate change. Variables that describe the size of the tree, like diameter and height are directly associated with biomass, which allows the use of regression models to estimate this element. Therefore, this study aimed to estimate by regression models, the biomass of different compartments of natural regeneration of trees of a Pinus taeda L. stand. The data were obtained through direct destructive method, using 100 randomly selected trees in the understory of a stand of Pinus taeda. We analyzed three arithmetical models, three logarithmic and two models developed by Stepwise process. Logarithmic equations developed by Stepwise procedure showed the best estimates of total and stems biomass. However, for needles and twigs compartments the best adjust was observed with Husch model and for root biomass Berkhout model proved to be the most suitable.

  4. Remark on natural models of neutrinos

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo

    2005-01-01

    We comment on what 't Hooft's naturalness argument implies with regard to a minimal extension of the Standard Model that incorporates right-handed neutrinos with generic mass terms. If this Lagrangian is taken as that of a low energy effective theory, the idea of pseudo-Dirac neutrinos with very small masses is consistent with 't Hooft's naturalness argument. This argument is based on the observation that the right-handed components of neutrinos in the massless limit exhibit an extra enhanced symmetry which is absent in other charged fermions. This enhanced symmetry is reminiscent of the Nambu-Goldstone fermions associated with spontaneously broken supersymmetry. The conventional seesaw scenario gives another natural solution if the ultra-heavy right-handed neutrinos are integrated out in the formulation of a low energy effective theory. (author)

  5. Real time natural object modeling framework

    International Nuclear Information System (INIS)

    Rana, H.A.; Shamsuddin, S.M.; Sunar, M.H.

    2008-01-01

    CG (Computer Graphics) is a key technology for producing visual contents. Currently computer generated imagery techniques are being developed and applied, particularly in the field of virtual reality applications, film production, training and flight simulators, to provide total composition of realistic computer graphic images. Natural objects like clouds are an integral feature of the sky without them synthetic outdoor scenes seem unrealistic. Modeling and animating such objects is a difficult task. Most systems are difficult to use, as they require adjustment of numerous, complex parameters and are non-interactive. This paper presents an intuitive, interactive system to artistically model, animate, and render visually convincing clouds using modern graphics hardware. A high-level interface models clouds through the visual use of cubes. Clouds are rendered by making use of hardware accelerated API -OpenGL. The resulting interactive design and rendering system produces perceptually convincing cloud models that can be used in any interactive system. (author)

  6. Modelling emissions from natural gas flaring

    Directory of Open Access Journals (Sweden)

    G. Ezaina Umukoro

    2017-04-01

    Full Text Available The world today recognizes the significance of environmental sustainability to the development of nations. Hence, the role oil and gas industry plays in environmental degrading activities such as gas flaring is of global concern. This study presents material balance equations and predicts results for non-hydrocarbon emissions such as CO2, CO, NO, NO2, and SO2 etc. from flaring (combustion of 12 natural gas samples representing composition of natural gas of global origin. Gaseous emission estimates and pattern were modelled by coding material balance equations for six reaction types and combustion conditions with a computer program. On the average, anticipated gaseous emissions from flaring natural gas with an average annual global flaring rate 126 bcm per year (between 2000 and 2011 in million metric tonnes (mmt are 560 mmt, 48 mmt, 91 mmt, 93 mmt and 50 mmt for CO2, CO, NO, NO2 and SO2 respectively. This model predicted gaseous emissions based on the possible individual combustion types and conditions anticipated in gas flaring operation. It will assist in the effort by environmental agencies and all concerned to track and measure the extent of environmental pollution caused by gas flaring operations in the oil and gas industry.

  7. Structural equation modeling and natural systems

    Science.gov (United States)

    Grace, James B.

    2006-01-01

    This book, first published in 2006, presents an introduction to the methodology of structural equation modeling, illustrates its use, and goes on to argue that it has revolutionary implications for the study of natural systems. A major theme of this book is that we have, up to this point, attempted to study systems primarily using methods (such as the univariate model) that were designed only for considering individual processes. Understanding systems requires the capacity to examine simultaneous influences and responses. Structural equation modeling (SEM) has such capabilities. It also possesses many other traits that add strength to its utility as a means of making scientific progress. In light of the capabilities of SEM, it can be argued that much of ecological theory is currently locked in an immature state that impairs its relevance. It is further argued that the principles of SEM are capable of leading to the development and evaluation of multivariate theories of the sort vitally needed for the conservation of natural systems.

  8. Complexity, Modeling, and Natural Resource Management

    Directory of Open Access Journals (Sweden)

    Paul Cilliers

    2013-09-01

    Full Text Available This paper contends that natural resource management (NRM issues are, by their very nature, complex and that both scientists and managers in this broad field will benefit from a theoretical understanding of complex systems. It starts off by presenting the core features of a view of complexity that not only deals with the limits to our understanding, but also points toward a responsible and motivating position. Everything we do involves explicit or implicit modeling, and as we can never have comprehensive access to any complex system, we need to be aware both of what we leave out as we model and of the implications of the choice of our modeling framework. One vantage point is never sufficient, as complexity necessarily implies that multiple (independent conceptualizations are needed to engage the system adequately. We use two South African cases as examples of complex systems - restricting the case narratives mainly to the biophysical domain associated with NRM issues - that make the point that even the behavior of the biophysical subsystems themselves are already complex. From the insights into complex systems discussed in the first part of the paper and the lessons emerging from the way these cases have been dealt with in reality, we extract five interrelated generic principles for practicing science and management in complex NRM environments. These principles are then further elucidated using four further South African case studies - organized as two contrasting pairs - and now focusing on the more difficult organizational and social side, comparing the human organizational endeavors in managing such systems.

  9. Decision support models for natural gas dispatch

    International Nuclear Information System (INIS)

    Chin, L.; Vollmann, T.E.

    1992-01-01

    A decision support model is presented which will give utilities the support tools to manage the purchasing of natural gas supplies in the most cost effective manner without reducing winter safety stocks to below minimum levels. In Business As Usual (BAU) purchasing quantities vary with the daily forecasts. With Material Requirements Planning (MRP) and Linear Programming (LP), two types of factors are used: seasonal weather and decision rule. Under current practices, BAU simulation uses the least expensive gas source first, then adding successively more expensive sources. Material Requirements Planning is a production planning technique which uses a parent item master production schedule to determine time phased requirements for component points. Where the MPS is the aggregate gas demand forecasts for the contract year. This satisfies daily demand with least expensive gas and uses more expensive when necessary with automatic computation of available-to-promise (ATP) gas a dispacher knows daily when extra gas supplies may be ATP. Linear Programming is a mathematical algorithm used to determine optimal allocations of scarce resources to achieve a desired result. The LP model determines optimal daily gas purchase decisions with respect to supply cost minimization. Using these models, it appears possible to raise gross income margins 6 to 10% with minimal additions of customers and no new gas supply

  10. Decision support models for natural gas dispatch

    Energy Technology Data Exchange (ETDEWEB)

    Chin, L. (Bentley College, Waltham, MA (United States)); Vollmann, T.E. (International Inst. for Management Development, Lausanne (Switzerland))

    A decision support model is presented which will give utilities the support tools to manage the purchasing of natural gas supplies in the most cost effective manner without reducing winter safety stocks to below minimum levels. In Business As Usual (BAU) purchasing quantities vary with the daily forecasts. With Material Requirements Planning (MRP) and Linear Programming (LP), two types of factors are used: seasonal weather and decision rule. Under current practices, BAU simulation uses the least expensive gas source first, then adding successively more expensive sources. Material Requirements Planning is a production planning technique which uses a parent item master production schedule to determine time phased requirements for component points. Where the MPS is the aggregate gas demand forecasts for the contract year. This satisfies daily demand with least expensive gas and uses more expensive when necessary with automatic computation of available-to-promise (ATP) gas a dispacher knows daily when extra gas supplies may be ATP. Linear Programming is a mathematical algorithm used to determine optimal allocations of scarce resources to achieve a desired result. The LP model determines optimal daily gas purchase decisions with respect to supply cost minimization. Using these models, it appears possible to raise gross income margins 6 to 10% with minimal additions of customers and no new gas supply.

  11. Modeling Recognition Memory Using the Similarity Structure of Natural Input

    Science.gov (United States)

    Lacroix, Joyca P. W.; Murre, Jaap M. J.; Postma, Eric O.; van den Herik, H. Jaap

    2006-01-01

    The natural input memory (NAM) model is a new model for recognition memory that operates on natural visual input. A biologically informed perceptual preprocessing method takes local samples (eye fixations) from a natural image and translates these into a feature-vector representation. During recognition, the model compares incoming preprocessed…

  12. Modeling recognition memory using the similarity structure of natural input

    NARCIS (Netherlands)

    Lacroix, J.P.W.; Murre, J.M.J.; Postma, E.O.; van den Herik, H.J.

    2006-01-01

    The natural input memory (NIM) model is a new model for recognition memory that operates on natural visual input. A biologically informed perceptual preprocessing method takes local samples (eye fixations) from a natural image and translates these into a feature-vector representation. During

  13. Modelling of Natural and Hybrid Ventilation

    OpenAIRE

    Heiselberg, Per

    2006-01-01

    The effectiveness of natural ventilation, i.e. its ability to ensure indoor air quality and passive cooling in a building, depends greatly on the design process. Mechanical ventilation systems can be designed separately from the design of the building in which they are installed. They can also be installed in existing buildings after a few modifications. In contrast, ventilation systems using only natural forces such as wind and thermal buoyancy need to be designed together with the building,...

  14. Cathepsin B & L are not required for ebola virus replication.

    Science.gov (United States)

    Marzi, Andrea; Reinheckel, Thomas; Feldmann, Heinz

    2012-01-01

    Ebola virus (EBOV), family Filoviridae, emerged in 1976 on the African continent. Since then it caused several outbreaks of viral hemorrhagic fever in humans with case fatality rates up to 90% and remains a serious Public Health concern and biothreat pathogen. The most pathogenic and best-studied species is Zaire ebolavirus (ZEBOV). EBOV encodes one viral surface glycoprotein (GP), which is essential for replication, a determinant of pathogenicity and an important immunogen. GP mediates viral entry through interaction with cellular surface molecules, which results in the uptake of virus particles via macropinocytosis. Later in this pathway endosomal acidification activates the cysteine proteases Cathepsin B and L (CatB, CatL), which have been shown to cleave ZEBOV-GP leading to subsequent exposure of the putative receptor-binding and fusion domain and productive infection. We studied the effect of CatB and CatL on in vitro and in vivo replication of EBOV. Similar to previous findings, our results show an effect of CatB, but not CatL, on ZEBOV entry into cultured cells. Interestingly, cell entry by other EBOV species (Bundibugyo, Côte d'Ivoire, Reston and Sudan ebolavirus) was independent of CatB or CatL as was EBOV replication in general. To investigate whether CatB and CatL have a role in vivo during infection, we utilized the mouse model for ZEBOV. Wild-type (control), catB(-/-) and catL(-/-) mice were equally susceptible to lethal challenge with mouse-adapted ZEBOV with no difference in virus replication and time to death. In conclusion, our results show that CatB and CatL activity is not required for EBOV replication. Furthermore, EBOV glycoprotein cleavage seems to be mediated by an array of proteases making targeted therapeutic approaches difficult.

  15. Cathepsin B & L are not required for ebola virus replication.

    Directory of Open Access Journals (Sweden)

    Andrea Marzi

    Full Text Available Ebola virus (EBOV, family Filoviridae, emerged in 1976 on the African continent. Since then it caused several outbreaks of viral hemorrhagic fever in humans with case fatality rates up to 90% and remains a serious Public Health concern and biothreat pathogen. The most pathogenic and best-studied species is Zaire ebolavirus (ZEBOV. EBOV encodes one viral surface glycoprotein (GP, which is essential for replication, a determinant of pathogenicity and an important immunogen. GP mediates viral entry through interaction with cellular surface molecules, which results in the uptake of virus particles via macropinocytosis. Later in this pathway endosomal acidification activates the cysteine proteases Cathepsin B and L (CatB, CatL, which have been shown to cleave ZEBOV-GP leading to subsequent exposure of the putative receptor-binding and fusion domain and productive infection. We studied the effect of CatB and CatL on in vitro and in vivo replication of EBOV. Similar to previous findings, our results show an effect of CatB, but not CatL, on ZEBOV entry into cultured cells. Interestingly, cell entry by other EBOV species (Bundibugyo, Côte d'Ivoire, Reston and Sudan ebolavirus was independent of CatB or CatL as was EBOV replication in general. To investigate whether CatB and CatL have a role in vivo during infection, we utilized the mouse model for ZEBOV. Wild-type (control, catB(-/- and catL(-/- mice were equally susceptible to lethal challenge with mouse-adapted ZEBOV with no difference in virus replication and time to death. In conclusion, our results show that CatB and CatL activity is not required for EBOV replication. Furthermore, EBOV glycoprotein cleavage seems to be mediated by an array of proteases making targeted therapeutic approaches difficult.

  16. Modelling of Natural and Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    The effectiveness of natural ventilation, i.e. its ability to ensure indoor air quality and passive cooling in a building, depends greatly on the design process. Mechanical ventilation systems can be designed separately from the design of the building in which they are installed. They can also...... be installed in existing buildings after a few modifications. In contrast, ventilation systems using only natural forces such as wind and thermal buoyancy need to be designed together with the building, since the building itself and its components are the elements that can reduce or increase air movement...... as well as influence the air content (dust, pollution etc.). Architects and engineers need to acquire qualitative and quantitative information about the interactions between building characteristics and natural ventilation in order to design buildings and systems consistent with a passive low...

  17. The Nature of Information Science: Changing Models

    Science.gov (United States)

    Robinson, Lyn; Karamuftuoglu, Murat

    2010-01-01

    Introduction: This paper considers the nature of information science as a discipline and profession. Method: It is based on conceptual analysis of the information science literature, and consideration of philosophical perspectives, particularly those of Kuhn and Peirce. Results: It is argued that information science may be understood as a field of…

  18. Modeling Child–Nature Interaction in a Nature Preschool: A Proof of Concept

    Directory of Open Access Journals (Sweden)

    Peter H. Kahn

    2018-05-01

    Full Text Available This article provides a proof of concept for an approach to modeling child–nature interaction based on the idea of interaction patterns: characterizations of essential features of interaction between humans and nature, specified abstractly enough such that countless different instantiations of each one can occur – in more domestic or wild forms – given different types of nature, people, and purposes. The model draws from constructivist psychology, ecological psychology, and evolutionary psychology, and is grounded in observational data collected through a time-sampling methodology at a nature preschool. Through using a nature language that emphasizes ontogenetic and phylogenetic significance, seven keystone interaction patterns are described for this nature preschool: using one’s body vigorously in nature, striking wood on wood, constructing shelter, being in solitude in nature, lying on earth, cohabiting with a wild animal, and being outside in weather. These 7 interactions patterns are then brought together with 13 other patterns published elsewhere to provide a total of 20 keystone interaction patterns that begin to fill out the model, and to show its promise. Discussion focuses on what the model aims to be in terms of both product and process, on what work the model can currently do, and how to further develop the model.

  19. Natural gas supply in Denmark - A model of natural gas transmission and the liberalized gas market

    International Nuclear Information System (INIS)

    Bregnbaek, L.

    2005-01-01

    In the wake of the liberalization of European energy markets a large area of research has spawned. This area includes the development of mathematical models to analyze the impact of liberalization with respect to efficiency, supply security and environment, to name but a few subjects. This project describes the development of such a model. In Denmark the parallel liberalization of the markets of natural gas and electricity and the existence of an abundance of de-centralized combined heat and power generators of which most are natural gas fired, leads to the natural assumption that the future holds a greater deal of interdependency for these markets. A model is developed describing network flows in the natural gas transmission system, the main arteries of natural gas supply, from a technical viewpoint. This yields a technical bounding on the supply available in different parts of the country. Additionally the economic structure of the Danish natural gas market is formulated mathematically giving a description of the transmission, distribution and storage options available to the market. The supply and demand of natural gas is put into a partial equilibrium context by integrating the developed model with the Balmorel model, which describes the markets for electricity and district heat. Specifically on the demand side the consumption of natural gas for heat and power generation is emphasized. General results and three demonstration cases are presented to illustrate how the developed model can be used to analyze various energy policy issues, and to disclose the strengths and weaknesses in the formulation. (au)

  20. Natural climate variability in a coupled model

    International Nuclear Information System (INIS)

    Zebiak, S.E.; Cane, M.A.

    1990-01-01

    Multi-century simulations with a simplified coupled ocean-atmosphere model are described. These simulations reveal an impressive range of variability on decadal and longer time scales, in addition to the dominant interannual el Nino/Southern Oscillation signal that the model originally was designed to simulate. Based on a very large sample of century-long simulations, it is nonetheless possible to identify distinct model parameter sensitivities that are described here in terms of selected indices. Preliminary experiments motivated by general circulation model results for increasing greenhouse gases suggest a definite sensitivity to model global warming. While these results are not definitive, they strongly suggest that coupled air-sea dynamics figure prominently in global change and must be included in models for reliable predictions

  1. Modelling indoor exposure to natural radioactive nuclides

    International Nuclear Information System (INIS)

    Hofmann, W.; Daschil, F.

    1986-01-01

    Radon enters buildings from several sources primarily from building materials and from the soil or rocks that underlie or surround building fundaments. A multicompartment model was developed which describes the fate of radon and attached or free radon decay products in a model room by a set of linear time-dependent differential equations. Time-dependent coefficients allow to model temporal parameter changes, e.g. the opening of windows, or a sudden pressure drop leading to enhanced exhalation. While steady-state models were used to study the effect of parameter changes on steady state nuclide concentrations, the time-dependent models provided additional information on the time scale of these changes. (author)

  2. Modelling of anthropogenic and natural climate changes

    Energy Technology Data Exchange (ETDEWEB)

    Grassl, H; Mikolajewicz, U; Bakan, S [Max Planck Institute of Meteorology, Hamburg (Germany)

    1993-06-01

    The delay of anthropogenic climate change caused by oceans and other slowly reacting climate system components forces us to numerical modeling as the basis of decisions. For three three-dimensional numerical examples, namely transient coupled ocean-atmosphere models for the additional greenhouse effect, internal ocean-atmosphere variability, and disturbance by soot particles from burning oil wells, the present-day status is described. From all anthropogenic impacts on the radiative balance, the contribution from trace gases is the most important.

  3. Partially natural Two Higgs Doublet Models

    Energy Technology Data Exchange (ETDEWEB)

    Draper, Patrick [Department of Physics, University of California,Broida Hall, Santa Barbara, CA 93106 (United States); Haber, Howard E. [Santa Cruz Institute for Particle Physics, University of California,1156 High Street, Santa Cruz, CA 95064 (United States); Kavli Institute for Theoretical Physics, University of California,Kohn Hall, Santa Barbara, CA 93106 (United States); Ruderman, Joshua T. [Center for Cosmology and Particle Physics, Department of Physics, New York University,4 Washington Pl. New York, NY 10003 (United States)

    2016-06-21

    It is possible that the electroweak scale is low due to the fine-tuning of microscopic parameters, which can result from selection effects. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would seem to disfavor this possibility, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. We discuss counterexamples where the Higgs boson is light because of fine-tuning, and a second scalar doublet is light because a discrete symmetry relates its mass to the mass of the Standard Model Higgs boson. Our examples require new vectorlike fermions at the electroweak scale, and the models possess a rich electroweak vacuum structure. The mechanism that we discuss does not protect a small CP-odd Higgs mass in split or high-scale supersymmetry-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.

  4. Natural class of non-Peccei-Quinn models

    International Nuclear Information System (INIS)

    Barr, S.M.

    1984-01-01

    We discuss a class of models, not based on the Peccei-Quinn mechanism, that solve the strong CP problem. These are a generalization of a model of A. Nelson. Improved conditions are given for such models. These conditions are natural and in many simple models are automatically satisfied. 19 references

  5. Understanding Surface Adhesion in Nature: A Peeling Model.

    Science.gov (United States)

    Gu, Zhen; Li, Siheng; Zhang, Feilong; Wang, Shutao

    2016-07-01

    Nature often exhibits various interesting and unique adhesive surfaces. The attempt to understand the natural adhesion phenomena can continuously guide the design of artificial adhesive surfaces by proposing simplified models of surface adhesion. Among those models, a peeling model can often effectively reflect the adhesive property between two surfaces during their attachment and detachment processes. In the context, this review summarizes the recent advances about the peeling model in understanding unique adhesive properties on natural and artificial surfaces. It mainly includes four parts: a brief introduction to natural surface adhesion, the theoretical basis and progress of the peeling model, application of the peeling model, and finally, conclusions. It is believed that this review is helpful to various fields, such as surface engineering, biomedicine, microelectronics, and so on.

  6. Model documentation: Natural gas transmission and distribution model of the National Energy Modeling System. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-17

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of integrated Analysis and Forecasting of the Energy information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas. The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The methodology employed allows the analysis of impacts of regional capacity constraints in the interstate natural gas pipeline network and the identification of pipeline capacity expansion requirements. There is an explicit representation of core and noncore markets for natural gas transmission and distribution services, and the key components of pipeline tariffs are represented in a pricing algorithm. Natural gas pricing and flow patterns are derived by obtaining a market equilibrium across the three main elements of the natural gas market: the supply element, the demand element, and the transmission and distribution network that links them. The NGTDM consists of four modules: the Annual Flow Module, the Capacity F-expansion Module, the Pipeline Tariff Module, and the Distributor Tariff Module. A model abstract is provided in Appendix A.

  7. Model documentation: Natural gas transmission and distribution model of the National Energy Modeling System. Volume 1

    International Nuclear Information System (INIS)

    1995-01-01

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of integrated Analysis and Forecasting of the Energy information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas. The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The methodology employed allows the analysis of impacts of regional capacity constraints in the interstate natural gas pipeline network and the identification of pipeline capacity expansion requirements. There is an explicit representation of core and noncore markets for natural gas transmission and distribution services, and the key components of pipeline tariffs are represented in a pricing algorithm. Natural gas pricing and flow patterns are derived by obtaining a market equilibrium across the three main elements of the natural gas market: the supply element, the demand element, and the transmission and distribution network that links them. The NGTDM consists of four modules: the Annual Flow Module, the Capacity F-expansion Module, the Pipeline Tariff Module, and the Distributor Tariff Module. A model abstract is provided in Appendix A

  8. Modelling natural disturbances in forest ecosystems: a review

    OpenAIRE

    Seidl, Rupert; Fernandes, Paulo M.; Fonseca, Teresa F.; Gillet, François; Jönsson, Anna Maria; Merganičová, Katarína; Netherer, Sigrid; Arpaci, Alexander; Bontemps, Jean-Daniel; Bugmann, Harald

    2011-01-01

    Natural disturbances play a key role in ecosystem dynamics and are important factors for sustainable forest ecosystem management. Quantitative models are frequently employed to tackle the complexities associated with disturbance processes. Here we review the wide variety of approaches to modelling natural disturbances in forest ecosystems, addressing the full spectrum of disturbance modelling from single events to integrated disturbance regimes. We applied a general, process-based framework f...

  9. Computer modelling of contaminant migration in natural disperse media

    International Nuclear Information System (INIS)

    Kundas, S.P.; Gishkelyuk, I.A.; Khil'ko, O.S.

    2012-01-01

    The theoretical foundations for modeling of the contaminants migration in natural disperses media taking into account interconnected heat and moisture transport are developed. The calculation of mass transfer parameters based on adsorption isotherms of water and thermodynamic equations in the developed mathematical models. The artificial neural networks use to predict migration of contaminants in natural disperse media is proposed. The developed software package is presented and results of practical application of models and software are discussed. (authors)

  10. Quantifying the 'naturalness' of the curvaton model

    International Nuclear Information System (INIS)

    Lerner, Rose N.; Melville, Scott

    2014-02-01

    We investigate the probability of obtaining an observable curvature perturbation, using as an example the minimal curvaton-Higgs (MCH) model. We determine 'probably observable' and 'probably excluded' regions of parameter space assuming generic initial conditions and applying a stochastic approach for the curvaton's evolution during inflation. Inflation is assumed to last longer than the N obs ≅55 observable e-folds, and the total number of e-folds of inflation determines the particular ranges of parameters that are probable. For the MCH model, these 'probably observable' regions always lie within the range 8 x 10 4 GeV≤m σ ≤2 x 10 7 GeV, where m σ is the curvaton mass, and the Hubble scale at horizon exit is chosen as H * =10 10 GeV. Because the 'probably observable' region depends on the total duration of inflation, information on parameters in the Lagrangian from particle physics and from precision CMB observables can therefore provide information about the total duration of inflation, not just the last N obs e-folds. This method could also be applied to any model that contains additional scalar fields to determine the probability that these scalar fields contribute to the curvature perturbation.

  11. Computational fluid dynamics modelling of displacement natural ventilation.

    OpenAIRE

    Ji, Yingchun

    2005-01-01

    Natural ventilation is widely recognised as contributing towards low-energy building design. The requirement to reduce energy usage in new buildings has rejuvenated interest in natural ventilation. This thesis deals with computer modelling of natural displacement ventilation driven either by buoyancy or buoyancy combined with wind forces. Two benchmarks have been developed using computational fluid dynamics (CFD) in order to evaluate the accuracy with which CFD is able to mo...

  12. Natural Convection Analysis with Various Turbulent Models Using FLUENT

    International Nuclear Information System (INIS)

    Park, Yu Sun

    2007-01-01

    The buoyancy driven convective flow fields are steady circulatory flows which were made between surfaces maintained at two fixed temperatures. They are ubiquitous in nature and play an important role in many engineering applications. Especially, in last decades, natural convection in a close loop or cavity becomes the main issue in the molecular biology for the polymerase chain reaction (PCR). Application of a natural convection can reduce the costs and efforts remarkably. This paper focuses on the sensitivity study of turbulence analysis using CFD for a natural convection in a closed rectangular cavity. Using commercial CFD code, FLUENT, various turbulent models were applied to the turbulent flow. Results from each CFD model will be compared each other in the viewpoints of flow characteristics. This work will suggest the best turbulent model of CFD for analyzing turbulent flows of the natural convection in an enclosure system

  13. A new approach of the B.L.E.V.E. ( Boiling liquid expanding vapour explosion) and of its consequences; Une nouvelle approche

    Energy Technology Data Exchange (ETDEWEB)

    Asselin, D. [Shell LPG Europe (Country unknown/Code not available)

    1997-12-31

    The objectives of the B.L.E.V.E modeling are to get a better understanding of physical phenomenons, the mechanisms, the effects and the prevention, a better evaluation of the consequences, modeling of effects on man, determination of the safety distances. The model allows to take less penalizing safety distances and about the secondary overpressure effect the confinement must stay the general order. (N.C.)

  14. A Working Model of Natural Selection Illustrated by Table Tennis

    Science.gov (United States)

    Dinc, Muhittin; Kilic, Selda; Aladag, Caner

    2013-01-01

    Natural selection is one of the most important topics in biology and it helps to clarify the variety and complexity of organisms. However, students in almost every stage of education find it difficult to understand the mechanism of natural selection and they can develop misconceptions about it. This article provides an active model of natural…

  15. Surface chemistry of cellulose : from natural fibres to model surfaces

    NARCIS (Netherlands)

    Kontturi, E.J.

    2005-01-01

    The theme of the thesis was to link together the research aspects of cellulose occurring in nature (in natural wood fibres) and model surfaces of cellulose. Fundamental changes in cellulose (or fibre) during recycling of paper was a pragmatic aspect which was retained throughout the thesis with

  16. Using STELLA Simulation Models to Teach Natural Resource Economics

    Science.gov (United States)

    Dissanayake, Sahan T. M.

    2016-01-01

    In this article, the author discusses how graphical simulation models created using STELLA software can be used to present natural resource systems in an intuitive way in undergraduate natural resource economics classes based on his experiences at a leading research university, a state university, and a leading liberal arts college in the United…

  17. On natural hierarchy in dynamically broken gauge models

    International Nuclear Information System (INIS)

    Frere, J.M.

    1980-01-01

    A model based on dynamical symmetry breaking provides a naturally large 'mass hierarchy'. Few fermions are needed at intermediate energies, and asymptotic freedom of usual interactions is therefore not imperiled. (orig.)

  18. Numerical Speadsheet Modeling of Natural Attenuation for Groundwater Contaminant Plumes

    National Research Council Canada - National Science Library

    Twesme, Troy

    1999-01-01

    .... The model was used to evaluate natural attenuation for removal of a trichloroethylene (TCE) plume from a surficial aquifer containing three regions with distinctly different processes for degradation of TCE...

  19. [Ecotourism exploitation model in Bita Lake Natural Reserve of Yunnan].

    Science.gov (United States)

    Yang, G; Wang, Y; Zhong, L

    2000-12-01

    Bita lake provincial natural reserve is located in Shangri-La region of North-western Yunnan, and was set as a demonstrating area for ecotourism exploitation in 1998. After a year's exploitation construction and half a year's operation as a branch of the 99' Kunming International Horticulture Exposition to accept tourists, it was proved that the ecotourism demonstrating area attained four integrated functions of ecotourism, i.e., tourism, protection, poverty clearing and environment education. Five exploitation and management models including function zoned exploitation model, featured tourism communication model signs system designing model, local Tibetan family reception model and environmental monitoring model, were also successful, which were demonstrated and spreaded to the whole province. Bita lake provincial natural reserve could be a good sample for the ecotourism exploitation natural reserves of the whole country.

  20. A Model of Composite \\textit{B}\\,--\\,\\textit{L} Asymmetric Dark Matter

    OpenAIRE

    Ibe, Masahiro; Kamada, Ayuki; Kobayashi, Shin; Nakano, Wakutaka

    2018-01-01

    As the $B-L$ gauge symmetry is the most plausible addition among the various extensions of the Standard Model, it is attractive to identify symmetry which stabilizes dark matter with the $B-L$ gauge symmetry. Besides, dark matter which is stabilized by $B-L$ naturally leads to asymmetric dark matter. In this paper, we construct a model of composite asymmetric dark matter in a bottom-up approach. By assuming that the entropy of the dark sector is released to the Standard Model sector through a...

  1. Modeling and forecasting natural gas demand in Bangladesh

    International Nuclear Information System (INIS)

    Wadud, Zia; Dey, Himadri S.; Kabir, Md. Ashfanoor; Khan, Shahidul I.

    2011-01-01

    Natural gas is the major indigenous source of energy in Bangladesh and accounts for almost one-half of all primary energy used in the country. Per capita and total energy use in Bangladesh is still very small, and it is important to understand how energy, and natural gas demand will evolve in the future. We develop a dynamic econometric model to understand the natural gas demand in Bangladesh, both in the national level, and also for a few sub-sectors. Our demand model shows large long run income elasticity - around 1.5 - for aggregate demand for natural gas. Forecasts into the future also show a larger demand in the future than predicted by various national and multilateral organizations. Even then, it is possible that our forecasts could still be at the lower end of the future energy demand. Price response was statistically not different from zero, indicating that prices are possibly too low and that there is a large suppressed demand for natural gas in the country. - Highlights: → Natural gas demand is modeled using dynamic econometric methods, first of its kind in Bangladesh. → Income elasticity for aggregate natural gas demand in Bangladesh is large-around 1.5. → Demand is price insensitive, indicating too low prices and/or presence of large suppressed demand. → Demand forecasts reveal large divergence from previous estimates, which is important for planning. → Attempts to model demand for end-use sectors were successful only for the industrial sector.

  2. Modeling and forecasting natural gas demand in Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Wadud, Zia, E-mail: ziawadud@yahoo.com [Bangladesh University of Engineering and Technology (Bangladesh); Dey, Himadri S. [University of Notre Dame (United States); Kabir, Md. Ashfanoor; Khan, Shahidul I. [Bangladesh University of Engineering and Technology (Bangladesh)

    2011-11-15

    Natural gas is the major indigenous source of energy in Bangladesh and accounts for almost one-half of all primary energy used in the country. Per capita and total energy use in Bangladesh is still very small, and it is important to understand how energy, and natural gas demand will evolve in the future. We develop a dynamic econometric model to understand the natural gas demand in Bangladesh, both in the national level, and also for a few sub-sectors. Our demand model shows large long run income elasticity - around 1.5 - for aggregate demand for natural gas. Forecasts into the future also show a larger demand in the future than predicted by various national and multilateral organizations. Even then, it is possible that our forecasts could still be at the lower end of the future energy demand. Price response was statistically not different from zero, indicating that prices are possibly too low and that there is a large suppressed demand for natural gas in the country. - Highlights: > Natural gas demand is modeled using dynamic econometric methods, first of its kind in Bangladesh. > Income elasticity for aggregate natural gas demand in Bangladesh is large-around 1.5. > Demand is price insensitive, indicating too low prices and/or presence of large suppressed demand. > Demand forecasts reveal large divergence from previous estimates, which is important for planning. > Attempts to model demand for end-use sectors were successful only for the industrial sector.

  3. Development of a natural Gas Systems Analysis Model (GSAM)

    International Nuclear Information System (INIS)

    Godec, M.; Haas, M.; Pepper, W.; Rose, J.

    1993-01-01

    Recent dramatic changes in natural gas markets have significant implications for the scope and direction of DOE's upstream as well as downstream natural gas R ampersand D. Open access transportation changes the way gas is bought and sold. The end of the gas deliverability surplus requires increased reserve development above recent levels. Increased gas demand for power generation and other new uses changes the overall demand picture in terms of volumes, locations and seasonality. DOE's Natural Gas Strategic Plan requires that its R ampersand D activities be evaluated for their ability to provide adequate supplies of reasonably priced gas. Potential R ampersand D projects are to be evaluated using a full fuel cycle, benefit-cost approach to estimate likely market impact as well as technical success. To assure R ampersand D projects are evaluated on a comparable basis, METC has undertaken the development of a comprehensive natural gas technology evaluation framework. Existing energy systems models lack the level of detail required to estimate the impact of specific upstream natural gas technologies across the known range of geological settings and likely market conditions. Gas Systems Analysis Model (GSAM) research during FY 1993 developed and implemented this comprehensive, consistent natural gas system evaluation framework. Rather than a isolated research activity, however, GSAM represents the integration of many prior and ongoing natural gas research efforts. When complete, it will incorporate the most current resource base description, reservoir modeling, technology characterization and other geologic and engineering aspects developed through recent METC and industry gas R ampersand D programs

  4. Model documentation Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    International Nuclear Information System (INIS)

    1996-01-01

    The Natural Gas Transmission and Distribution Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural gas forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues

  5. Model documentation Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-26

    The Natural Gas Transmission and Distribution Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural gas forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.

  6. Decision support for natural resource management; models and evaluation methods

    NARCIS (Netherlands)

    Wessels, J.; Makowski, M.; Nakayama, H.

    2001-01-01

    When managing natural resources or agrobusinesses, one always has to deal with autonomous processes. These autonomous processes play a core role in designing model-based decision support systems. This chapter tries to give insight into the question of which types of models might be used in which

  7. Modelling natural disturbances in forest ecosystems: a review

    NARCIS (Netherlands)

    Seidl, R.; Fernandes, P.M.; Fonseca, T.F.; Gillet, F.; Jöhnsson, A.M.; Merganičová, K.; Netherer, S.; Arpaci, A.; Bontemps, J.D.; Bugmann, H.; González-Olabarria, J.R.; Lasch, P.; Meredieu, C.; Moreira, F.; Schelhaas, M.; Mohren, G.M.J.

    2011-01-01

    Natural disturbances play a key role in ecosystem dynamics and are important factors for sustainable forest ecosystem management. Quantitative models are frequently employed to tackle the complexities associated with disturbance processes. Here we review the wide variety of approaches to modelling

  8. Thermodynamic Modeling of Natural Gas Systems Containing Water

    DEFF Research Database (Denmark)

    Karakatsani, Eirini K.; Kontogeorgis, Georgios M.

    2013-01-01

    As the need for dew point specifications remains very urgent in the natural gas industry, the development of accurate thermodynamic models, which will match experimental data and will allow reliable extrapolations, is needed. Accurate predictions of the gas phase water content in equilibrium...... with a heavy phase were previously obtained using cubic plus association (CPA) coupled with a solid phase model in the case of hydrates, for the binary systems of water–methane and water–nitrogen and a few natural gas mixtures. In this work, CPA is being validated against new experimental data, both water...... content and phase equilibrium data, and solid model parameters are being estimated for four natural gas main components (methane, ethane, propane, and carbon dioxide). Different tests for the solid model parameters are reported, including vapor-hydrate-equilibria (VHE) and liquid-hydrate-equilibria (LHE...

  9. Turbulence modeling of natural convection in enclosures: A review

    International Nuclear Information System (INIS)

    Choi, Seok Ki; Kim, Seong O

    2012-01-01

    In this paper a review of recent developments of turbulence models for natural convection in enclosures is presented. The emphasis is placed on the effect of the treatments of Reynolds stress and turbulent heat flux on the stability and accuracy of the solution for natural convection in enclosures. The turbulence models considered in the preset study are the two-layer k -ε model, the shear stress transport (SST) model, the elliptic-relaxation (V2-f) model and the elliptic-blending second-moment closure (EBM). Three different treatments of the turbulent heat flux are the generalized gradient diffusion hypothesis (GGDH), the algebraic flux model (AFM) and the differential flux model (DFM). The mathematical formulation of the above turbulence models and their solution method are presented. Evaluation of turbulence models are performed for turbulent natural convection in a 1:5 rectangular cavity ( Ra = 4.3x10 10 ) and in a square cavity with conducting top and bottom walls ( Ra =1.58x10 9 ) and the Rayleigh-Benard convection ( Ra = 2x10 6 ∼ Ra =10 9 ). The relative performances of turbulence models are examined and their successes and shortcomings are addressed

  10. Perefirma lööb läbi ühise tahtega / Ave Paavo

    Index Scriptorium Estoniae

    Paavo, Ave

    2005-01-01

    Perefirma lööb läbi, kui on ühine tahe ja suhted korras. Vt. samas: Töö eesmärk on leivateenimine. OÜ Arenet Servis näitel; Toivo Kens. Investeerime tulevastesse põlvkondadesse. OÜ Viraito näitrel; Kalle Elster. Meie eelis on üksteise kiire mõistmine. AS-i Elstera näitel

  11. Numerical modeling of underground storage system for natural gas

    Science.gov (United States)

    Ding, J.; Wang, S.

    2017-12-01

    Natural gas is an important type of base-load energy, and its supply needs to be adjusted according to different demands in different seasons. For example, since natural gas is increasingly used to replace coal for winter heating, the demand for natural gas in winter is much higher than that in other seasons. As storage systems are the essential tools for balancing seasonal supply and demand, the design and simulation of natural gas storage systems form an important research direction. In this study, a large-scale underground storage system for natural gas is simulated based on theoretical analysis and finite element modeling.It is proven that the problem of axi-symmetric Darcy porous flow of ideal gas is governed by the Boussinesq equation. In terms of the exact solution to the Boussinesq equation, the basic operating characteristics of the underground storage system is analyzed, and it is demonstrated that the propagation distance of the pore pressure is proportional to the 1/4 power of the mass flow rate and to the 1/2 power of the propagation time. This quantitative relationship can be used to guide the overall design of natural gas underground storage systems.In order to fully capture the two-way coupling between pore pressure and elastic matrix deformation, a poro-elastic finite element model for natural gas storage is developed. Based on the numerical model, the dynamic processes of gas injection, storage and extraction are simulated, and the corresponding time-dependent surface deformations are obtained. The modeling results not only provide a theoretical basis for real-time monitoring for the operating status of the underground storage system through surface deformation measurements, but also demonstrate that a year-round balance can be achieved through periodic gas injection and extraction.This work is supported by the CAS "100 talents" Program and the National Natural Science Foundation of China (41371090).

  12. Adverse Selection Models with Three States of Nature

    Directory of Open Access Journals (Sweden)

    Daniela MARINESCU

    2011-02-01

    Full Text Available In the paper we analyze an adverse selection model with three states of nature, where both the Principal and the Agent are risk neutral. When solving the model, we use the informational rents and the efforts as variables. We derive the optimal contract in the situation of asymmetric information. The paper ends with the characteristics of the optimal contract and the main conclusions of the model.

  13. Matrix diffusion model. In situ tests using natural analogues

    Energy Technology Data Exchange (ETDEWEB)

    Rasilainen, K. [VTT Energy, Espoo (Finland)

    1997-11-01

    Matrix diffusion is an important retarding and dispersing mechanism for substances carried by groundwater in fractured bedrock. Natural analogues provide, unlike laboratory or field experiments, a possibility to test the model of matrix diffusion in situ over long periods of time. This thesis documents quantitative model tests against in situ observations, done to support modelling of matrix diffusion in performance assessments of nuclear waste repositories. 98 refs. The thesis includes also eight previous publications by author.

  14. Matrix diffusion model. In situ tests using natural analogues

    International Nuclear Information System (INIS)

    Rasilainen, K.

    1997-11-01

    Matrix diffusion is an important retarding and dispersing mechanism for substances carried by groundwater in fractured bedrock. Natural analogues provide, unlike laboratory or field experiments, a possibility to test the model of matrix diffusion in situ over long periods of time. This thesis documents quantitative model tests against in situ observations, done to support modelling of matrix diffusion in performance assessments of nuclear waste repositories

  15. Can Nature Protection be Unsustainable? Models Behind Nature Protection in New Zealands National Parks

    Science.gov (United States)

    Hauhs, Michael; Bogner, Christina

    2013-04-01

    Nature protection can be justified by intrinsic values of life. Western culture sees nature as an autonomous system. Thus, nature protection is often synonymous with refraining from human interference as much as possible. This, however, can pose at least technical problems. Indeed, historical human impacts such as introduced species are often irreversible. In such cases refraining from human interference to protect threatened species is not an adequate management response. Nature protection in New Zealand is a prominent example. Many introduced species make a non-interventionist attitude infeasible to protect endemic species such as kiwis. Actually, active human interference is necessary to attain this goal. Therefore, one may consider nature protection as another form of land use. As any other form of land use, it needs standards of proper management (i.e. explicit goals, assessment, intervention etc.). In other words, it has to be shown to be sustainable. However, sustainability may rigorously be defined as an attribute of past land use only. Instantaneous positive indicators of sustainability may be elusive. At best it can be decided by observation whether or not a land use has been (not) sustainable until now. Stakeholders of nature protection have often different (implicit) concepts or models of nature in mind. This can lead to conflicts when it comes to management decisions. For example, the methods by which conservationists in New Zealand seek to re-establish historical species assemblages (e.g. aerial drop of poison into national parks) have come under criticism of animal rights groups as non-humane. We propose to use abstract modelling language to classify these concepts of nature protection and related issues. We show that from modelling perspective these conflicts pose a basic science problem rather than an applied science problem. This makes the delegation into existing disciplines so hard. We discuss possible implications for nature protection

  16. A multiple-location model for natural gas forward curves

    International Nuclear Information System (INIS)

    Buffington, J.C.

    1999-06-01

    This thesis presents an approach for financial modelling of natural gas in which connections between locations are incorporated and the complexities of forward curves in natural gas are considered. Apart from electricity, natural gas is the most volatile commodity traded. Its price is often dependent on the weather and price shocks can be felt across several geographic locations. This modelling approach incorporates multiple risk factors that correspond to various locations. One of the objectives was to determine if the model could be used for closed-form option prices. It was suggested that an adequate model for natural gas must consider 3 statistical properties: volatility term structure, backwardation and contango, and stochastic basis. Data from gas forward prices at Chicago, NYMEX and AECO were empirically tested to better understand these 3 statistical properties at each location and to verify if the proposed model truly incorporates these properties. In addition, this study examined the time series property of the difference of two locations (the basis) and determines that these empirical properties are consistent with the model properties. Closed-form option solutions were also developed for call options of forward contracts and call options on forward basis. The options were calibrated and compared to other models. The proposed model is capable of pricing options, but the prices derived did not pass the test of economic reasonableness. However, the model was able to capture the effect of transportation as well as aspects of seasonality which is a benefit over other existing models. It was determined that modifications will be needed regarding the estimation of the convenience yields. 57 refs., 2 tabs., 7 figs., 1 append

  17. Natural Circulation Phenomena and Modelling for Advanced Water Cooled Reactors

    International Nuclear Information System (INIS)

    2012-03-01

    The role of natural circulation in advanced water cooled reactor design has been extended with the adoption of passive safety systems. Some designs utilize natural circulation to remove core heat during normal operation. Most passive safety systems used in evolutionary and innovative water cooled reactor designs are driven by natural circulation. The use of passive systems based on natural circulation can eliminate the costs associated with the installation, maintenance and operation of active systems that require multiple pumps with independent and redundant electric power supplies. However, considering the weak driving forces of passive systems based on natural circulation, careful design and analysis methods must be employed to ensure that the systems perform their intended functions. Several IAEA Member States with advanced reactor development programmes are actively conducting investigations of natural circulation to support the development of advanced water cooled reactor designs with passive safety systems. To foster international collaboration on the enabling technology of passive systems that utilize natural circulation, in 2004 the IAEA initiated a coordinated research project (CRP) on Natural Circulation Phenomena, Modelling and Reliability of Passive Systems that Utilize Natural Circulation. Three reports were published within the framework of this CRP. The first report (IAEA-TECDOC-1474) contains the material developed for the first IAEA training course on natural circulation in water cooled nuclear power plants. The second report (IAEA-TECDOC-1624) describes passive safety systems in a wide range of advanced water cooled nuclear power plant designs, with the goal of gaining insights into system design, operation and reliability. This third, and last, report summarizes the research studies completed by participating institutes during the CRP period.

  18. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  19. PWR hot leg natural circulation modeling with MELCOR code

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hong; Lee, Jong In [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1998-12-31

    Previous MELCOR and SCDAP/RELAP5 nodalizations for simulating the counter-current, natural circulation behavior of vapor flow within the RCS hot legs and SG U-tubes when core damage progress can not be applied to the steady state and water-filled conditions during the initial period of accident progression because of the artificially high loss coefficients in the hot legs and SG U-tubes which were chosen from results of COMMIX calculation and the Westinghouse natural circulation experiments in a 1/7-scale facility for simulating steam natural circulation behavior in the vessel and circulation modeling which can be used both for the liquid flow condition at steady state and for the vapor flow condition at the later period of in-vessel core damage. For this, the drag forces resulting from the momentum exchange effects between the two vapor streams in the hot leg was modeled as a pressure drop by pump model. This hot leg natural circulation modeling of MELCOR was able to reproduce similar mass flow rates with those predicted by previous models. 6 refs., 2 figs. (Author)

  20. Modeling of Natural Self-Pressurized Circulation Circuits

    International Nuclear Information System (INIS)

    Zanocco, Pablo; Gimenez, Marcelo; Delmastro, Dario

    2003-01-01

    In this work, HUARPE code models for self-pressurized two-phase natural convection systems are improved.A drift-flux model is included, allowing the modeling of the relative velocity between phases.The model of steam dome structures is improved, with a thermal resistance scheme, in order to model the material thermal conductivity.This allows improving thermal losses modeling and structures dynamic.'Shape functions' are implemented based on analytic solutions for pressure derivative and density in each node, which allows less diffusive solving schemes, more appropriate for analyzing cases involving density waves phenomena.Finally, pressure evolutions during a pressurization transient are analyzed, comparing the new models and the previous version results.These results are also checked against RELAP code ones, obtained with different dome nodalizations. Moreover, modeling problems are analyzed for each case

  1. Model documentation: Natural Gas Transmission and Distribution Model of the National Energy Modeling System; Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-02-24

    The Natural Gas Transmission and Distribution Model (NGTDM) is a component of the National Energy Modeling System (NEMS) used to represent the domestic natural gas transmission and distribution system. NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the Energy Information Administration (EIA) and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. This report documents the archived version of NGTDM that was used to produce the natural gas forecasts used in support of the Annual Energy Outlook 1994, DOE/EIA-0383(94). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. It is intended to fulfill the legal obligation of the EIA to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). This report represents Volume 1 of a two-volume set. (Volume 2 will report on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.) Subsequent chapters of this report provide: (1) an overview of the NGTDM (Chapter 2); (2) a description of the interface between the National Energy Modeling System (NEMS) and the NGTDM (Chapter 3); (3) an overview of the solution methodology of the NGTDM (Chapter 4); (4) the solution methodology for the Annual Flow Module (Chapter 5); (5) the solution methodology for the Distributor Tariff Module (Chapter 6); (6) the solution methodology for the Capacity Expansion Module (Chapter 7); (7) the solution methodology for the Pipeline Tariff Module (Chapter 8); and (8) a description of model assumptions, inputs, and outputs (Chapter 9).

  2. A new approach to Naturalness in SUSY models

    CERN Document Server

    Ghilencea, D M

    2013-01-01

    We review recent results that provide a new approach to the old problem of naturalness in supersymmetric models, without relying on subjective definitions for the fine-tuning associated with {\\it fixing} the EW scale (to its measured value) in the presence of quantum corrections. The approach can address in a model-independent way many questions related to this problem. The results show that naturalness and its measure (fine-tuning) are an intrinsic part of the likelihood to fit the data that {\\it includes} the EW scale. One important consequence is that the additional {\\it constraint} of fixing the EW scale, usually not imposed in the data fits of the models, impacts on their overall likelihood to fit the data (or chi^2/ndf, ndf: number of degrees of freedom). This has negative implications for the viability of currently popular supersymmetric extensions of the Standard Model.

  3. The Effect of Computer Models as Formative Assessment on Student Understanding of the Nature of Models

    Science.gov (United States)

    Park, Mihwa; Liu, Xiufeng; Smith, Erica; Waight, Noemi

    2017-01-01

    This study reports the effect of computer models as formative assessment on high school students' understanding of the nature of models. Nine high school teachers integrated computer models and associated formative assessments into their yearlong high school chemistry course. A pre-test and post-test of students' understanding of the nature of…

  4. Fishing for Nature's Hits: Establishment of the Zebrafish as a Model for Screening Antidiabetic Natural Products.

    Science.gov (United States)

    Tabassum, Nadia; Tai, Hongmei; Jung, Da-Woon; Williams, Darren R

    2015-01-01

    Diabetes mellitus affects millions of people worldwide and significantly impacts their quality of life. Moreover, life threatening diseases, such as myocardial infarction, blindness, and renal disorders, increase the morbidity rate associated with diabetes. Various natural products from medicinal plants have shown potential as antidiabetes agents in cell-based screening systems. However, many of these potential "hits" fail in mammalian tests, due to issues such as poor pharmacokinetics and/or toxic side effects. To address this problem, the zebrafish (Danio rerio) model has been developed as a "bridge" to provide an experimentally convenient animal-based screening system to identify drug candidates that are active in vivo. In this review, we discuss the application of zebrafish to drug screening technologies for diabetes research. Specifically, the discovery of natural product-based antidiabetes compounds using zebrafish will be described. For example, it has recently been demonstrated that antidiabetic natural compounds can be identified in zebrafish using activity guided fractionation of crude plant extracts. Moreover, the development of fluorescent-tagged glucose bioprobes has allowed the screening of natural product-based modulators of glucose homeostasis in zebrafish. We hope that the discussion of these advances will illustrate the value and simplicity of establishing zebrafish-based assays for antidiabetic compounds in natural products-based laboratories.

  5. A Simple Model for Human and Nature Interaction

    Science.gov (United States)

    Motesharrei, S.; Rivas, J.; Kalnay, E.

    2012-12-01

    There are widespread concerns that current trends in population and resource-use are unsustainable, but the possibilities of an overshoot and collapse remain unclear and controversial. Collapses of civilizations have occurred many times in the past 5000 years, often followed by centuries of economic, intellectual, and population decline. Many different natural and social phenomena have been invoked to explain specific collapses, but a general explanation remains elusive. Two important features seem to appear across societies that have collapsed: Ecological Strain and Economic Stratification. Our new model (Human And Nature DYnamics, HANDY) has just four equations that describe the evolution of Elites, Commoners, Nature, and Wealth. Mechanisms leading to collapse are discussed and the measure "Carrying Capacity" is developed and defined. The model shows that societal collapse can happen due to either one of two independent factors: (1) over-consumption of natural resources, and/or (2) deep inequity between Elites and Commoners. The model also portrays two distinct types of collapse: (i) collapse followed by recovery of nature, and (ii) full collapse. The model suggests that the estimation of Carrying Capacity is a practical means for early detection of a collapse. Collapse can be avoided, and population can reach a sustainable equilibrium, if the rate of depletion of nature is reduced to a sustainable level, and if resources are distributed in a reasonably equitable fashion.; A type-ii (full) collapse is shown in this figure. With high inequality and high depletion, societies are doomed to collapse. Wealth starts to decrease when population rises above the carrying capacity. The large gap between carrying capacity and its maximum is a result of depletion factor being much larger than the sustainable limit. ; It is possible to overshoot, oscillate, and eventually converge to an equilibrium, even in an inequitable society. However, it requires policies that control

  6. Natural crayfish clone as emerging model for various biological ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 36; Issue 2. Marmorkrebs: Natural crayfish clone as emerging model for various biological disciplines. Günter Vogt. Mini-review Volume 36 Issue 2 June 2011 pp 377-382. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Nature of Science and Models: Comparing Portuguese Prospective Teachers' Views

    Science.gov (United States)

    Torres, Joana; Vasconcelos, Clara

    2015-01-01

    Despite the relevance of nature of science and scientific models in science education, studies reveal that students do not possess adequate views regarding these topics. Bearing in mind that both teachers' views and knowledge strongly influence students' educational experiences, the main scope of this study was to evaluate Portuguese prospective…

  8. Sensitivity study of CFD turbulent models for natural convection analysis

    International Nuclear Information System (INIS)

    Yu sun, Park

    2007-01-01

    The buoyancy driven convective flow fields are steady circulatory flows which were made between surfaces maintained at two fixed temperatures. They are ubiquitous in nature and play an important role in many engineering applications. Application of a natural convection can reduce the costs and efforts remarkably. This paper focuses on the sensitivity study of turbulence analysis using CFD (Computational Fluid Dynamics) for a natural convection in a closed rectangular cavity. Using commercial CFD code, FLUENT and various turbulent models were applied to the turbulent flow. Results from each CFD model will be compared each other in the viewpoints of grid resolution and flow characteristics. It has been showed that: -) obtaining general flow characteristics is possible with relatively coarse grid; -) there is no significant difference between results from finer grid resolutions than grid with y + + is defined as y + = ρ*u*y/μ, u being the wall friction velocity, y being the normal distance from the center of the cell to the wall, ρ and μ being respectively the fluid density and the fluid viscosity; -) the K-ε models show a different flow characteristic from K-ω models or from the Reynolds Stress Model (RSM); and -) the y + parameter is crucial for the selection of the appropriate turbulence model to apply within the simulation

  9. Thermodynamic model of natural, medieval and nuclear waste glass durability

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Plodinec, M.J.

    1983-01-01

    A thermodynamic model of glass durability based on hydration of structural units has been applied to natural glass, medieval window glasses, and glasses containing nuclear waste. The relative durability predicted from the calculated thermodynamics correlates directly with the experimentally observed release of structural silicon in the leaching solution in short-term laboratory tests. By choosing natural glasses and ancient glasses whose long-term performance is known, and which bracket the durability of waste glasses, the long-term stability of nuclear waste glasses can be interpolated among these materials. The current Savannah River defense waste glass formulation is as durable as natural basalt from the Hanford Reservation (10 6 years old). The thermodynamic hydration energy is shown to be related to the bond energetics of the glass. 69 references, 2 figures, 1 table

  10. Natural disasters impacting a macroeconomic model with endogenous dynamics

    International Nuclear Information System (INIS)

    Hallegatte, Stephane; Ghil, Michael

    2008-01-01

    We investigate the macroeconomic response to natural disasters by using an endogenous business cycle (EnBC) model in which cyclical behavior arises from the investment-profit instability. Our model exhibits a larger response to natural disasters during expansions than during recessions. This apparently paradoxical result can be traced to the disasters amplifying pre-existing disequilibria during expansions, while the existence of unused resources during recessions damps the exogenous shocks. It thus appears that high-growth periods are also highly vulnerable to supply-side shocks. In our EnBC model, the average production loss due to a set of disasters distributed at random in time is highly sensitive to the dynamical characteristics of the impacted economy. Larger economic flexibility allows for a more efficient and rapid response to supply-side shocks and reduces production losses. On the other hand, too high a flexibility can lead to vulnerability phases that cause average production losses to soar. These results raise questions about the assessment of climate change damages or natural disaster losses that are based purely on long-term growth models. (author)

  11. Diagnosing Students' Understanding of the Nature of Models

    Science.gov (United States)

    Gogolin, Sarah; Krüger, Dirk

    2017-10-01

    Students' understanding of models in science has been subject to a number of investigations. The instruments the researchers used are suitable for educational research but, due to their complexity, cannot be employed directly by teachers. This article presents forced choice (FC) tasks, which, assembled as a diagnostic instrument, are supposed to measure students' understanding of the nature of models efficiently, while being sensitive enough to detect differences between individuals. In order to evaluate if the diagnostic instrument is suitable for its intended use, we propose an approach that complies with the demand to integrate students' responses to the tasks into the validation process. Evidence for validity was gathered based on relations to other variables and on students' response processes. Students' understanding of the nature of models was assessed using three methods: FC tasks, open-ended tasks and interviews ( N = 448). Furthermore, concurrent think-aloud protocols ( N = 30) were performed. The results suggest that the method and the age of the students have an effect on their understanding of the nature of models. A good understanding of the FC tasks as well as a convergence in the findings across the three methods was documented for grades eleven and twelve. This indicates that teachers can use the diagnostic instrument for an efficient and, at the same time, valid diagnosis for this group. Finally, the findings of this article may provide a possible explanation for alternative findings from previous studies as a result of specific methods that were used.

  12. Marine Natural Products as Models to Circumvent Multidrug Resistance

    Directory of Open Access Journals (Sweden)

    Solida Long

    2016-07-01

    Full Text Available Multidrug resistance (MDR to anticancer drugs is a serious health problem that in many cases leads to cancer treatment failure. The ATP binding cassette (ABC transporter P-glycoprotein (P-gp, which leads to premature efflux of drugs from cancer cells, is often responsible for MDR. On the other hand, a strategy to search for modulators from natural products to overcome MDR had been in place during the last decades. However, Nature limits the amount of some natural products, which has led to the development of synthetic strategies to increase their availability. This review summarizes the research findings on marine natural products and derivatives, mainly alkaloids, polyoxygenated sterols, polyketides, terpenoids, diketopiperazines, and peptides, with P-gp inhibitory activity highlighting the established structure-activity relationships. The synthetic pathways for the total synthesis of the most promising members and analogs are also presented. It is expected that the data gathered during the last decades concerning their synthesis and MDR-inhibiting activities will help medicinal chemists develop potential drug candidates using marine natural products as models which can deliver new ABC transporter inhibitor scaffolds.

  13. Naturalness of CP Violation in the Standard Model

    International Nuclear Information System (INIS)

    Gibbons, Gary W.; Gielen, Steffen; Pope, C. N.; Turok, Neil

    2009-01-01

    We construct a natural measure on the space of Cabibbo-Kobayashi-Maskawa matrices in the standard model, assuming the fermion mass matrices are randomly selected from a distribution which incorporates the observed quark mass hierarchy. This measure allows us to assess the likelihood of Jarlskog's CP violation parameter J taking its observed value J≅3x10 -5 . We find that the observed value, while well below the mathematically allowed maximum, is in fact typical once the observed quark masses are assumed

  14. Development of a natural Gas Systems Analysis Model (GSAM)

    International Nuclear Information System (INIS)

    1994-02-01

    Lacking a detailed characterization of the resource base and a comprehensive borehole-to-burnertip evaluation model of the North American natural gas system, past R ampersand D, tax and regulatory policies have been formulated without a full understanding of their likely direct and indirect impacts on future gas supply and demand. The recent disappearance of the deliverability surplus, pipeline deregulation, and current policy debates about regulatory initiatives in taxation, environmental compliance and leasing make the need for a comprehensive gas evaluation system critical. Traditional econometric or highly aggregated energy models are increasingly regarded as unable to incorporate available geologic detail and explicit technology performance and costing algorithms necessary to evaluate resource-technology-economic interactions in a market context. The objective of this research is to create a comprehensive, non-proprietary, microcomputer model of the North American natural gas system. GSAM explicitly evaluates the key components of the natural gas system, including resource base, exploration and development, extraction technology performance and costs, transportation and storage and end use. The primary focus is the detailed characterization of the resource base at the reservoir and sub-reservoir level and the impact of alternative extraction technologies on well productivity and economics. GSAM evaluates the complex interactions of current and alternative future technology and policy initiatives in the context of the evolving gas markets. Scheduled for completion in 1995, a prototype is planned for early 1994. ICF Resources reviewed relevant natural gas upstream, downstream and market models to identify appropriate analytic capabilities to incorporate into GSAM. We have reviewed extraction technologies to better characterize performance and costs in terms of GSAM parameters

  15. Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-01-01

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas. The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. Subsequent chapters of this report provide: an overview of NGTDM; a description of the interface between the NEMS and NGTDM; an overview of the solution methodology of the NGTDM; the solution methodology for the Annual Flow Module; the solution methodology for the Distributor Tariff Module; the solution methodology for the Capacity Expansion Module; the solution methodology for the Pipeline Tariff Module; and a description of model assumptions, inputs, and outputs.

  16. The Tangled Nature Model of evolutionary dynamics reconsidered

    DEFF Research Database (Denmark)

    Andersen, Christian Walther; Sibani, Paolo

    2016-01-01

    The Tangled Nature Model of biological and cultural evolution features interacting agents which compete for limited resources and reproduce in an error prone fashion and at a rate depending on the `tangle' of interactions they maintain with others. The set of interactions linking a TNM individual....... To bring out the structural and dynamical effects of trait inheritance , we introduce and numerically analyze a family of TNM models where a positive integer $K$ parametrises correlations between the interactions of an agent and those of its mutated offspring. For $K=1$ a single point mutation randomizes...

  17. Overview of the EPRI CONTRACTMIX model for natural gas applications

    International Nuclear Information System (INIS)

    1993-09-01

    The Contract Mix Model (CONTRACTMIX) is designed to assist gas supply planners in analyzing the costs and risks of alternative supply strategies. By explicitly incorporating uncertainty about gas demand and market conditions into the analysis, the methodology permits the analyst to compare contracting strategies on the basis of cost and risk and to assess the value of flexible strategies and contracts. The model is applicable to purchase decisions for natural gas and other fuels. CONTRACTMIX may be used at all phases of supply decision-making, from broad strategy formulation to detailed contract design and evaluation. This document introduces the prospective user to the model's capability for analysis of gas supply contracting decisions. The document describes the types of problems CONTRACTMIX is designed to address as well as the model's structure, inputs, outputs, and unique features

  18. A complementarity model for the European natural gas market

    International Nuclear Information System (INIS)

    Egging, Ruud; Gabriel, Steven A.; Holz, Franziska; Zhuang, Jifang

    2008-01-01

    In this paper, we present a detailed and comprehensive complementarity model for computing market equilibrium values in the European natural gas system. Market players include producers and their marketing arms which we call 'traders', pipeline and storage operators, marketers, LNG liquefiers, regasifiers, tankers, and three end-use consumption sectors. The economic behavior of producers, traders, pipeline and storage operators, liquefiers and regasifiers is modeled via optimization problems whose Karush-Kuhn-Tucker (KKT) optimality conditions in combination with market-clearing conditions form the complementarity system. The LNG tankers, marketers and consumption sectors are modeled implicitly via appropriate cost functions, aggregate demand curves, and ex post calculations, respectively. The model is run on several case studies that highlight its capabilities, including a simulation of a disruption of Russian supplies via Ukraine

  19. Use of natural geochemical tracers to improve reservoir simulation models

    Energy Technology Data Exchange (ETDEWEB)

    Huseby, O.; Chatzichristos, C.; Sagen, J.; Muller, J.; Kleven, R.; Bennett, B.; Larter, S.; Stubos, A.K.; Adler, P.M.

    2005-01-01

    This article introduces a methodology for integrating geochemical data in reservoir simulations to improve hydrocarbon reservoir models. The method exploits routine measurements of naturally existing inorganic ion concentration in hydrocarbon reservoir production wells, and uses the ions as non-partitioning water tracers. The methodology is demonstrated on a North Sea field case, using the field's reservoir model, together with geochemical information (SO{sub 4}{sup 2}, Mg{sup 2+} K{sup +}, Ba{sup 2+}, Sr{sup 2+}, Ca{sup 2+}, Cl{sup -} concentrations) from the field's producers. From the data-set we show that some of the ions behave almost as ideal sea-water tracers, i.e. without sorption to the matrix, ion-exchange with the matrix or scale-formation with other ions in the formation water. Moreover, the dataset shows that ion concentrations in pure formation-water vary according to formation. This information can be used to allocate produced water to specific water-producing zones in commingled production. Based on an evaluation of the applicability of the available data, one inorganic component, SO{sub 4}{sup 2}, is used as a natural seawater tracer. Introducing SO{sub 4}{sup 2} as a natural tracer in a tracer simulation has revealed a potential for improvements of the reservoir model. By tracking the injected seawater it was possible to identify underestimated fault lengths in the reservoir model. The demonstration confirms that geochemical data are valuable additional information for reservoir characterization, and shows that integration of geochemical data into reservoir simulation procedures can improve reservoir simulation models. (author)

  20. Modeling Natural Space Ionizing Radiation Effects on External Materials

    Science.gov (United States)

    Alstatt, Richard L.; Edwards, David L.; Parker, Nelson C. (Technical Monitor)

    2000-01-01

    Predicting the effective life of materials for space applications has become increasingly critical with the drive to reduce mission cost. Programs have considered many solutions to reduce launch costs including novel, low mass materials and thin thermal blankets to reduce spacecraft mass. Determining the long-term survivability of these materials before launch is critical for mission success. This presentation will describe an analysis performed on the outer layer of the passive thermal control blanket of the Hubble Space Telescope. This layer had degraded for unknown reasons during the mission, however ionizing radiation (IR) induced embrittlement was suspected. A methodology was developed which allowed direct comparison between the energy deposition of the natural environment and that of the laboratory generated environment. Commercial codes were used to predict the natural space IR environment model energy deposition in the material from both natural and laboratory IR sources, and design the most efficient test. Results were optimized for total and local energy deposition with an iterative spreadsheet. This method has been used successfully for several laboratory tests at the Marshall Space Flight Center. The study showed that the natural space IR environment, by itself, did not cause the premature degradation observed in the thermal blanket.

  1. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    Energy Technology Data Exchange (ETDEWEB)

    G. Saulnier and W. Statham

    2006-04-16

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table.

  2. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    International Nuclear Information System (INIS)

    G. Saulnier; W. Statham

    2006-01-01

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO 2 uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table

  3. Modeling the natural convective flow of micropolar nanofluids

    KAUST Repository

    Bourantas, Georgios

    2014-01-01

    A micropolar model for nanofluidic suspensions is proposed in order to investigate theoretically the natural convection of nanofluids. The microrotation of the nanoparticles seems to play a significant role into flow regime and in that manner it possibly can interpret the controversial experimental data and theoretical numerical results over the natural convection of nanofluids. Natural convection of a nanofluid in a square cavity is studied and computations are performed for Rayleigh number values up to 106, for a range of solid volume fractions (0 ≤ φ ≤ 0.2) and, different types of nanoparticles (Cu, Ag, Al2O3 and TiO 2). The theoretical results show that the microrotation of the nanoparticles in suspension in general decreases overall heat transfer from the heated wall and should not therefore be neglected when computing heat and fluid flow of micropolar fluids, as nanofluids. The validity of the proposed model is depicted by comparing the numerical results obtained with available experimental and theoretical data. © 2013 Elsevier Ltd. All rights reserved.

  4. Gas analysis modeling system forecast for the Energy Modeling Forum North American Natural Gas Market Study

    International Nuclear Information System (INIS)

    Mariner-Volpe, B.; Trapmann, W.

    1989-01-01

    The Gas Analysis Modeling System is a large computer-based model for analyzing the complex US natural gas industry, including production, transportation, and consumption activities. The model was developed and first used in 1982 after the passage of the NGPA, which initiated a phased decontrol of most natural gas prices at the wellhead. The categorization of gas under the NGPA and the contractual nature of the natural gas market, which existed at the time, were primary factors in the development of the basic structure of the model. As laws and regulations concerning the natural gas market have changed, the model has evolved accordingly. Recent increases in competition in the wellhead market have also led to changes in the model. GAMS produces forecasts of natural gas production, consumption, and prices annually through 2010. It is an engineering-economic model that incorporates several different mathematical structures in order to represent the interaction of the key groups involved in the natural gas market. GAMS has separate supply and demand components that are equilibrated for each year of the forecast by means of a detailed transaction network

  5. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    Energy Technology Data Exchange (ETDEWEB)

    G.J. Saulnier Jr; W. Statham

    2006-03-10

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 {+-} 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory

  6. THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL

    International Nuclear Information System (INIS)

    G.J. Saulnier Jr; W. Statham

    2006-01-01

    The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO 2 uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 ± 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory analysis

  7. NATGAS. A Model of the European Natural Gas Market

    International Nuclear Information System (INIS)

    Mulder, M; Zwart, G.

    2006-02-01

    The NATural GAS model is an integrated model of the European wholesale gas market providing long-run projections of supply, transport, storage and consumption patterns in the model region, aggregated in 5-year periods, distinguishing two seasons (winter and summer). Model results include levels of investment in the various branches, output and consumption, depletion of reserves and price levels. The NATGAS model computes long-term effects of policy measures on future gas production and gas prices in Europe. NATGAS is an equilibrium model describing behaviour of gas producers, investors in infrastructure (pipeline, LNG capacity, as well as storage), traders and consumers. NATGAS covers the main European demand regions, including the United Kingdom, Germany, the Netherlands and Italy. Moreover, it covers the main origins of supply on the European market, such as Russia, Norway, Algeria, the Netherlands, the United Kingdom and LNG. In this memorandum, we first discuss the theoretical background as well as the model specifications. Afterwards, we describe the data we used, present some results and assess validity by computing sensitivities and comparing with current developments

  8. Spatial Durbin model analysis macroeconomic loss due to natural disasters

    Science.gov (United States)

    Kusrini, D. E.; Mukhtasor

    2015-03-01

    Magnitude of the damage and losses caused by natural disasters is huge for Indonesia, therefore this study aimed to analyze the effects of natural disasters for macroeconomic losses that occurred in 115 cities/districts across Java during 2012. Based on the results of previous studies it is suspected that it contains effects of spatial dependencies in this case, so that the completion of this case is performed using a regression approach to the area, namely Analysis of Spatial Durbin Model (SDM). The obtained significant predictor variable is population, and predictor variable with a significant weighting is the number of occurrences of disasters, i.e., disasters in the region which have an impact on other neighboring regions. Moran's I index value using the weighted Queen Contiguity also showed significant results, meaning that the incidence of disasters in the region will decrease the value of GDP in other.

  9. Thermodynamic modelling of acid gas removal from natural gas using the Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

    2017-01-01

    Thermodynamics of natural gas sweetening process needs to be known for proper design of natural gas treating plants. Absorption with aqueous N-Methyldiethanolamine is currently the most commonly used process for removal of acid gas (CO2 and H2S) impurities from natural gas. Model parameters...... for the Extended UNIQUAC model have already been determined by the same authors to calculate single acid gas solubility in aqueous MDEA. In this study, the model is further extended to estimate solubility of CO2 and H2S and their mixture in aqueous MDEA at high pressures with methane as a makeup gas....

  10. Numerical Modelling of Extreme Natural Hazards in the Russian Seas

    Science.gov (United States)

    Arkhipkin, Victor; Dobrolyubov, Sergey; Korablina, Anastasia; Myslenkov, Stanislav; Surkova, Galina

    2017-04-01

    Storm surges and extreme waves are severe natural sea hazards. Due to the almost complete lack of natural observations of these phenomena in the Russian seas (Caspian, Black, Azov, Baltic, White, Barents, Okhotsk, Kara), especially about their formation, development and destruction, they have been studied using numerical simulation. To calculate the parameters of wind waves for the seas listed above, except the Barents Sea, the spectral model SWAN was applied. For the Barents and Kara seas we used WAVEWATCH III model. Formation and development of storm surges were studied using ADCIRC model. The input data for models - bottom topography, wind, atmospheric pressure and ice cover. In modeling of surges in the White and Barents seas tidal level fluctuations were used. They have been calculated from 16 harmonic constant obtained from global atlas tides FES2004. Wind, atmospheric pressure and ice cover was taken from the NCEP/NCAR reanalysis for the period from 1948 to 2010, and NCEP/CFSR reanalysis for the period from 1979 to 2015. In modeling we used both regular and unstructured grid. The wave climate of the Caspian, Black, Azov, Baltic and White seas was obtained. Also the extreme wave height possible once in 100 years has been calculated. The statistics of storm surges for the White, Barents and Azov Seas were evaluated. The contribution of wind and atmospheric pressure in the formation of surges was estimated. The technique of climatic forecast frequency of storm synoptic situations was developed and applied for every sea. The research was carried out with financial support of the RFBR (grant 16-08-00829).

  11. Transient modelling of a natural circulation loop under variable pressure

    International Nuclear Information System (INIS)

    Vianna, Andre L.B.; Faccini, Jose L.H.; Su, Jian; Instituto de Engenharia Nuclear

    2017-01-01

    The objective of the present work is to model the transient operation of a natural circulation loop, which is one-tenth scale in height to a typical Passive Residual Heat Removal system (PRHR) of an Advanced Pressurized Water Nuclear Reactor and was designed to meet the single and two-phase flow similarity criteria to it. The loop consists of a core barrel with electrically heated rods, upper and lower plena interconnected by hot and cold pipe legs to a seven-tube shell heat exchanger of countercurrent design, and an expansion tank with a descending tube. A long transient characterized the loop operation, during which a phenomenon of self-pressurization, without self-regulation of the pressure, was experimentally observed. This represented a unique situation, named natural circulation under variable pressure (NCVP). The self-pressurization was originated in the air trapped in the expansion tank and compressed by the loop water dilatation, as it heated up during each experiment. The mathematical model, initially oriented to the single-phase flow, included the heat capacity of the structure and employed a cubic polynomial approximation for the density, in the buoyancy term calculation. The heater was modelled taking into account the different heat capacities of the heating elements and the heater walls. The heat exchanger was modelled considering the coolant heating, during the heat exchanging process. The self-pressurization was modelled as an isentropic compression of a perfect gas. The whole model was computationally implemented via a set of finite difference equations. The corresponding computational algorithm of solution was of the explicit, marching type, as for the time discretization, in an upwind scheme, regarding the space discretization. The computational program was implemented in MATLAB. Several experiments were carried out in the natural circulation loop, having the coolant flow rate and the heating power as control parameters. The variables used in the

  12. Transient modelling of a natural circulation loop under variable pressure

    Energy Technology Data Exchange (ETDEWEB)

    Vianna, Andre L.B.; Faccini, Jose L.H.; Su, Jian, E-mail: avianna@nuclear.ufrj.br, E-mail: sujian@nuclear.ufrj.br, E-mail: faccini@ien.gov.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2017-07-01

    The objective of the present work is to model the transient operation of a natural circulation loop, which is one-tenth scale in height to a typical Passive Residual Heat Removal system (PRHR) of an Advanced Pressurized Water Nuclear Reactor and was designed to meet the single and two-phase flow similarity criteria to it. The loop consists of a core barrel with electrically heated rods, upper and lower plena interconnected by hot and cold pipe legs to a seven-tube shell heat exchanger of countercurrent design, and an expansion tank with a descending tube. A long transient characterized the loop operation, during which a phenomenon of self-pressurization, without self-regulation of the pressure, was experimentally observed. This represented a unique situation, named natural circulation under variable pressure (NCVP). The self-pressurization was originated in the air trapped in the expansion tank and compressed by the loop water dilatation, as it heated up during each experiment. The mathematical model, initially oriented to the single-phase flow, included the heat capacity of the structure and employed a cubic polynomial approximation for the density, in the buoyancy term calculation. The heater was modelled taking into account the different heat capacities of the heating elements and the heater walls. The heat exchanger was modelled considering the coolant heating, during the heat exchanging process. The self-pressurization was modelled as an isentropic compression of a perfect gas. The whole model was computationally implemented via a set of finite difference equations. The corresponding computational algorithm of solution was of the explicit, marching type, as for the time discretization, in an upwind scheme, regarding the space discretization. The computational program was implemented in MATLAB. Several experiments were carried out in the natural circulation loop, having the coolant flow rate and the heating power as control parameters. The variables used in the

  13. Eco Control of Agro Pests using Imaging, Modelling & Natural Predators

    Directory of Open Access Journals (Sweden)

    Fina Faithpraise

    2014-10-01

    Full Text Available Caterpillars in their various forms: size, shape, and colour cause significant harm to crops and humans. This paper offers a solution for the detection and control of caterpillars through the use of a sustainable pest control system that does not require the application of chemical pesticides, which damage human health and destroy the naturally beneficial insects within the environment. The proposed system is capable of controlling 80% of the population of caterpillars in less than 65 days by deploying a controlled number of larval parasitoid wasps (Cotesia Flavipes, Cameron into the crop environment. This is made possible by using a continuous time model of the interaction between the caterpillar and the Cotesia Flavipes (Cameron wasps using a set of simultaneous, non-linear, ordinary differential equations incorporating natural death rates based on the Weibull probability distribution function. A negative binomial distribution is used to model the efficiency and the probability that the wasp will find and parasitize a host larva. The caterpillar is presented in all its life-cycle stages of: egg, larva, pupa and adult and the Cotesia Flavipes (Cameron wasp is present as an adult larval parasitoid. Biological control modelling is used to estimate the quantity of the Cotesia Flavipes (Cameron wasps that should be introduced into the caterpillar infested environment to suppress its population density to an economically acceptable level within a prescribed number of days.

  14. Spending Natural Resource Revenues in an Altruistic Growth Model

    DEFF Research Database (Denmark)

    Frederiksen, Elisabeth Hermann

    This paper examines how revenues from a natural resource interact with growth and welfare in an overlapping generations model with altruism. The revenues are allocated between public productive services and direct transfers to members of society by spending policies. We analyze how these policies...... influence the dynamics, and how the dynamics are influenced by the abundance of the revenue. Abundant revenues may harm growth, but growth and welfare can be oppositely affected. We also provide the socially optimal policy. Overall, the analysis suggests that variation in the strength of altruism...

  15. Modelling of the relation of natural disasters and the economic ...

    African Journals Online (AJOL)

    It is obvious that economy and production and commerce ability of the countries are also under the influence of natural changes. But when the changes and natural challenges finds a high speed or volume, they are called natural incident or natural disaster. Natural incidents, in addition to damages to life and emotion that ...

  16. A transportable system of models for natural resource damage assessment

    International Nuclear Information System (INIS)

    Reed, M.; French, D.

    1992-01-01

    A system of computer models has been developed for assessment of natural resource economic damages resulting from spills of oil and hazardous materials in marine and fresh water environments. Under USA federal legislation, the results of the model system are presumed correct in damage litigation proceedings. The model can address a wide range of spatial and temporal scales. The equations describing the motion of both pollutants and biota are solved in three dimensions. The model can simulate continuous releases of a contaminant, with representation of complex coastal boundaries, variable bathymetry, multiple shoreline types, and spatially variable ecosystem habitats. A graphic user interface provides easy control of the system in addition to the ability to display elements of the underlying geographical information system data base. The model is implemented on a personal computer and on a UNIX workstation. The structure of the system is such that transport to new geographic regions can be accomplished relatively easily, requiring only the development of the appropriate physical, toxicological, biological, and economic data sets. Applications are currently in progress for USA inland and coastal waters, the Adriatic Sea, the Strait of Sicily, the Gulf of Suez, and the Baltic Sea. 4 refs., 2 figs

  17. A complementarity model for solving stochastic natural gas market equilibria

    International Nuclear Information System (INIS)

    Zhuang Jifang; Gabriel, Steven A.

    2008-01-01

    This paper presents a stochastic equilibrium model for deregulated natural gas markets. Each market participant (pipeline operators, producers, etc.) solves a stochastic optimization problem whose optimality conditions, when combined with market-clearing conditions give rise to a certain mixed complementarity problem (MiCP). The stochastic aspects are depicted by a recourse problem for each player in which the first-stage decisions relate to long-term contracts and the second-stage decisions relate to spot market activities for three seasons. Besides showing that such a market model is an instance of a MiCP, we provide theoretical results concerning long-term and spot market prices and solve the resulting MiCP for a small yet representative market. We also note an interesting observation for the value of the stochastic solution for non-optimization problems

  18. Entropy in the Tangled Nature Model of evolution

    DEFF Research Database (Denmark)

    Roach, Ty N.F.; Nulton, James; Sibani, Paolo

    2017-01-01

    Applications of entropy principles to evolution and ecology are of tantamount importance given the central role spatiotemporal structuring plays in both evolution and ecological succession. We obtain here a qualitative interpretation of the role of entropy in evolving ecological systems. Our...... interpretation is supported by mathematical arguments using simulation data generated by the Tangled Nature Model (TNM), a stochastic model of evolving ecologies. We define two types of configurational entropy and study their empirical time dependence obtained from the data. Both entropy measures increase...... logarithmically with time, while the entropy per individual decreases in time, in parallel with the growth of emergent structures visible from other aspects of the simulation. We discuss the biological relevance of these entropies to describe niche space and functional space of ecosystems, as well as their use...

  19. A complementarity model for solving stochastic natural gas market equilibria

    International Nuclear Information System (INIS)

    Jifang Zhuang; Gabriel, S.A.

    2008-01-01

    This paper presents a stochastic equilibrium model for deregulated natural gas markets. Each market participant (pipeline operators, producers, etc.) solves a stochastic optimization problem whose optimality conditions, when combined with market-clearing conditions give rise to a certain mixed complementarity problem (MiCP). The stochastic aspects are depicted by a recourse problem for each player in which the first-stage decisions relate to long-term contracts and the second-stage decisions relate to spot market activities for three seasons. Besides showing that such a market model is an instance of a MiCP, we provide theoretical results concerning long-term and spot market prices and solve the resulting MiCP for a small yet representative market. We also note an interesting observation for the value of the stochastic solution for non-optimization problems. (author)

  20. Model for Educational Game Using Natural User Interface

    Directory of Open Access Journals (Sweden)

    Azrulhizam Shapi’i

    2016-01-01

    Full Text Available Natural User Interface (NUI is a new approach that has become increasingly popular in Human-Computer Interaction (HCI. The use of this technology is widely used in almost all sectors, including the field of education. In recent years, there are a lot of educational games using NUI technology in the market such as Kinect game. Kinect is a sensor that can recognize body movements, postures, and voices in three dimensions. It enables users to control and interact with game without the need of using game controller. However, the contents of most existing Kinect games do not follow the standard curriculum in classroom, thus making it do not fully achieve the learning objectives. Hence, this research proposes a design model as a guideline in designing educational game using NUI. A prototype has been developed as one of the objectives in this study. The prototype is based on proposed model to ensure and assess the effectiveness of the model. The outcomes of this study conclude that the proposed model contributed to the design method for the development of the educational game using NUI. Furthermore, evaluation results of the prototype show a good response from participant and in line with the standard curriculum.

  1. [Compatible biomass models of natural spruce (Picea asperata)].

    Science.gov (United States)

    Wang, Jin Chi; Deng, Hua Feng; Huang, Guo Sheng; Wang, Xue Jun; Zhang, Lu

    2017-10-01

    By using nonlinear measurement error method, the compatible tree volume and above ground biomass equations were established based on the volume and biomass data of 150 sampling trees of natural spruce (Picea asperata). Two approaches, controlling directly under total aboveground biomass and controlling jointly from level to level, were used to design the compatible system for the total aboveground biomass and the biomass of four components (stem, bark, branch and foliage), and the total ground biomass could be estimated independently or estimated simultaneously in the system. The results showed that the R 2 of the one variable and bivariate compatible tree volume and aboveground biomass equations were all above 0.85, and the maximum value reached 0.99. The prediction effect of the volume equations could be improved significantly when tree height was included as predictor, while it was not significant in biomass estimation. For the compatible biomass systems, the one variable model based on controlling jointly from level to level was better than the model using controlling directly under total above ground biomass, but the bivariate models of the two methods were similar. Comparing the imitative effects of the one variable and bivariate compatible biomass models, the results showed that the increase of explainable variables could significantly improve the fitness of branch and foliage biomass, but had little effect on other components. Besides, there was almost no difference between the two methods of estimation based on the comparison.

  2. Integrated modeling of natural and human systems - problems and initiatives

    Science.gov (United States)

    Kessler, H.; Giles, J.; Gunnink, J.; Hughes, A.; Moore, R. V.; Peach, D.

    2009-12-01

    Governments and their executive agencies across the world are facing increasing pressure to make decisions about the management of resources in light of population growth and environmental change. In the UK and the Netherlands, for example, groundwater is becoming a scarce resource for large parts of its most densely populated areas. At the same time river and groundwater flooding resulting from high rainfall events are increasing in scale and frequency and sea level rise is threatening the defences of coastal cities. There is also a need for affordable housing, improved transport infrastructure and waste disposal as well as sources of renewable energy and sustainable food production. These challenges can only be resolved if solutions are based on sound scientific evidence. Although we have knowledge and understanding of many individual processes in the natural sciences it is clear that a single science discipline is unable to answer the questions and their inter-relationships. Modern science increasingly employs computer models to simulate the natural, economic and human system. Management and planning requires scenario modelling, forecasts and “predictions”. Although the outputs are often impressive in terms of apparent accuracy and visualisation, they are inherently not suited to simulate the response to feedbacks from other models of the earth system, such as the impact of human actions. Geological Survey Organisations (GSO) are increasingly employing advances in Information Technology to visualise and improve their understanding of geological systems. Instead of 2 dimensional paper maps and reports many GSOs now produce 3 dimensional geological framework models and groundwater flow models as their standard output. Additionally the British Geological Survey and the Geological Survey of the Netherlands have developed standard routines to link geological data to groundwater models, but these models are only aimed at solving one specific part of the earth

  3. Spatial Modeling of Risk in Natural Resource Management

    Directory of Open Access Journals (Sweden)

    Peter Jones

    2002-01-01

    Full Text Available Making decisions in natural resource management involves an understanding of the risk and uncertainty of the outcomes, such as crop failure or cattle starvation, and of the normal spread of the expected production. Hedging against poor outcomes often means lack of investment and slow adoption of new methods. At the household level, production instability can have serious effects on income and food security. At the national level, it can have social and economic impacts that may affect all sectors of society. Crop models such as CERES-Maize are excellent tools for assessing weather-related production variability. WATBAL is a water balance model that can provide robust estimates of the potential growing days for a pasture. These models require large quantities of daily weather data that are rarely available. MarkSim is an application for generating synthetic daily weather files by estimating the third-order Markov model parameters from interpolated climate surfaces. The models can then be run for each distinct point on the map. This paper examines the growth of maize and pasture in dryland agriculture in southern Africa. Weather simulators produce independent estimates for each point on the map; however, we know that a spatial coherence of weather exists. We investigated a method of incorporating spatial coherence into MarkSim and show that it increases the variance of production. This means that all of the farmers in a coherent area share poor yields, with important consequences for food security, markets, transport, and shared grazing lands. The long-term aspects of risk are associated with global climate change. We used the results of a Global Circulation Model to extrapolate to the year 2055. We found that low maize yields would become more likely in the marginal areas, whereas they may actually increase in some areas. The same trend was found with pasture growth. We outline areas where further work is required before these tools and methods

  4. Advanced modeling of oxy-fuel combustion of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Chungen Yin

    2011-01-15

    The main goal of this small-scale project is to investigate oxy-combustion of natural gas (NG) through advanced modeling, in which radiation, chemistry and mixing will be reasonably resolved. 1) A state-of-the-art review was given regarding the latest R and D achievements and status of oxy-fuel technology. The modeling and simulation status and achievements in the field of oxy-fuel combustion were also summarized; 2) A computer code in standard c++, using the exponential wide band model (EWBM) to evaluate the emissivity and absorptivity of any gas mixture at any condition, was developed and validated in detail against data in literature. A new, complete, and accurate WSGGM, applicable to both air-fuel and oxy-fuel combustion modeling and applicable to both gray and non-gray calculation, was successfully derived, by using the validated EWBM code as the reference mode. The new WSGGM was implemented in CFD modeling of two different oxy-fuel furnaces, through which its great, unique advantages over the currently most widely used WSGGM were demonstrated. 3) Chemical equilibrium calculations were performed for oxy-NG flame and air-NG flame, in which dissociation effects were considered to different degrees. Remarkable differences in oxy-fuel and air-fuel combustion were revealed, and main intermediate species that play key roles in oxy-fuel flames were identified. Different combustion mechanisms are compared, e.g., the most widely used 2-step global mechanism, refined 4-step global mechanism, a global mechanism developed for oxy-fuel using detailed chemical kinetic modeling (CHEMKIN) as reference. 4) Over 15 CFD simulations were done for oxy-NG combustion, in which radiation, chemistry, mixing, turbulence-chemistry interactions, and so on were thoroughly investigated. Among all the simulations, RANS combined with 2-step and refined 4-step mechanism, RANS combined with CHEMKIN-based new global mechanism for oxy-fuel modeling, and LES combined with different combustion

  5. The light U boson as the mediator of a new force, coupled to a combination of Q, B, L and dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Fayet, Pierre [Laboratoire de Physique Theorique de l' Ecole Normale Superieure (CNRS UMR 8549, ENS, PSL Research University et UPMC, Sorbonne Universites), Paris Cedex 05 (France); Centre de Physique Theorique, Ecole polytechnique (CNRS UMR 7644, Universite Paris-Saclay), Palaiseau Cedex (France)

    2017-01-15

    A new light gauge boson U may have both vector and axial couplings. In a large class of theories, however, the new U(1) current J{sub F}{sup μ} naturally combines with the weak neutral current J{sup μ}{sub Z{sub s{sub m}}}, both parity-violating, into a vectorial current J{sub U}{sup μ}, combination of the B, L and electromagnetic currents with a possible dark-matter current. U{sup μ} may be expressed equivalently as cos ξC{sup μ} + sin ξ Z{sup μ}{sub sm} (''mixing with the Z'') or (1/cos χ) C{sup μ} + tan χ A{sup μ} (''mixing with the photon''), with C coupled to B, L and dark matter. The U boson may be viewed as a generalized dark photon, coupled to SM particles through Q{sub U} = Q+λ{sub B}B+λ{sub i}L{sub i}, with strength g''cos ξ cos{sup 2}θ = e tan χ. ''Kinetic-mixing'' terms, gauge invariant or not, simply correspond to a description in a non-orthogonal field basis (rather than to a new physical effect), with the dark photon in general also coupled to B and L. In a grand-unified theory Q{sub U}{sup gut} = Q - 2(B-L) at the GUT scale for SM particles, invariant under the SU(4) electrostrong symmetry group, with a non-vanishing ε = tan χ already present at the GUT scale, leading to Q{sub U} ≅ Q - 1.64 (B-L) at low energy. This also applies, for a very light or massless U boson, to a new long-range force, which could show up through apparent violations of the equivalence principle. (orig.)

  6. Climate and weather risk in natural resource models

    Science.gov (United States)

    Merrill, Nathaniel Henry

    This work, consisting of three manuscripts, addresses natural resource management under risk due to variation in climate and weather. In three distinct but theoretically related applications, I quantify the role of natural resources in stabilizing economic outcomes. In Manuscript 1, we address policy designed to effect the risk of cyanobacteria blooms in a drinking water reservoir through watershed wide policy. Combining a hydrologic and economic model for a watershed in Rhode Island, we solve for the efficient allocation of best management practices (BMPs) on livestock pastures to meet a monthly risk-based as well as mean-based water quality objective. In order to solve for the efficient allocations of nutrient control effort, we optimize a probabilistically constrained integer-programming problem representing the choices made on each farm and the resultant conditions that support cyanobacteria blooms. In doing so, we employ a genetic algorithm (GA). We hypothesize that management based on controlling the upper tail of the probability distribution of phosphorus loading implies different efficient management actions as compared to controlling mean loading. We find a shift to more intense effort on fewer acres when a probabilistic objective is specified with cost savings of meeting risk levels of up to 25% over mean loading based policies. Additionally, we illustrate the relative cost effectiveness of various policies designed to meet this risk-based objective. Rainfall and the subsequent overland runoff is the source of transportation of nutrients to a receiving water body, with larger amounts of phosphorus moving in more intense rainfall events. We highlight the importance of this transportation mechanism by comparing policies under climate change scenarios, where the intensity of rainfall is projected to increase and the time series process of rainfall to change. In Manuscript 2, we introduce a new economic groundwater model that incorporates the gradual shift

  7. Development of QSAR model for immunomodulatory activity of natural coumarinolignoids

    Directory of Open Access Journals (Sweden)

    Dharmendra K Yadav

    2010-07-01

    Full Text Available Dharmendra K Yadav, Abha Meena, Ankit Srivastava, D Chanda, Feroz Khan, SK ChattopadhyayMetabolic and Structural Biology Department, Central Institute of Medicinal and Aromatic Plants, Council of Scientific and Industrial Research, PO-CIMAP, IndiaAbstract: Immunomodulation is the process of alteration in immune response due to foreign intrusion of molecules inside the body. Along with the available drugs, a large number of herbal drugs are promoted in traditional Indian treatments, for their immunomodulating activity. Natural coumarinolignoids isolated from the seeds of Cleome viscose have been recognized as having hepatoprotective action and have recently been tested preclinically for their immunomodulatory activity affecting both cell-mediated and humoral immune response. To explore the immunomodulatory compound from derivatives of coumarinolignoids, a quantitative structure activity relationship (QSAR and molecular docking studies were performed. Theoretical results are in accord with the in vivo experimental data studied on Swiss albino mice. Immunostimulatory activity was predicted through QSAR model, developed by forward feed multiple linear regression method with leave-one-out approach. Relationship correlating measure of QSAR model was 99% (R2 = 0.99 and predictive accuracy was 96% (RCV2 = 0.96. QSAR studies indicate that dipole moment, steric energy, amide group count, lambda max (UV-visible, and molar refractivity correlates well with biological activity, while decrease in dipole moment, steric energy, and molar refractivity has negative correlation. Docking studies also showed strong binding affinity to immunomodulatory receptors.Keywords: coumarinolignoids, immunomodulation, docking, QSAR, regression model

  8. Disruption of River Networks in Nature and Models

    Science.gov (United States)

    Perron, J. T.; Black, B. A.; Stokes, M.; McCoy, S. W.; Goldberg, S. L.

    2017-12-01

    Many natural systems display especially informative behavior as they respond to perturbations. Landscapes are no exception. For example, longitudinal elevation profiles of rivers responding to changes in uplift rate can reveal differences among erosional mechanisms that are obscured while the profiles are in equilibrium. The responses of erosional river networks to perturbations, including disruption of their network structure by diversion, truncation, resurfacing, or river capture, may be equally revealing. In this presentation, we draw attention to features of disrupted erosional river networks that a general model of landscape evolution should be able to reproduce, including the consequences of different styles of planetary tectonics and the response to heterogeneous bedrock structure and deformation. A comparison of global drainage directions with long-wavelength topography on Earth, Mars, and Saturn's moon Titan reveals the extent to which persistent and relatively rapid crustal deformation has disrupted river networks on Earth. Motivated by this example and others, we ask whether current models of river network evolution adequately capture the disruption of river networks by tectonic, lithologic, or climatic perturbations. In some cases the answer appears to be no, and we suggest some processes that models may be missing.

  9. On flavour and naturalness of composite Higgs models

    International Nuclear Information System (INIS)

    Matsedonskyi, Oleksii

    2015-01-01

    We analyse the interplay of the constraints imposed on flavour-symmetric Composite Higgs models by Naturalness considerations and the constraints derived from Flavour Physics and Electroweak Precision Tests. Our analysis is based on the Effective Field Theory which describes the Higgs as a pseudo-Nambu-Goldstone boson and also includes the composite fermionic resonances. Within this approach one is able to identify the directions in the parameter space where the U(3)-symmetric flavour models can pass the current experimental constraints, without conflicting with the light Higgs mass. We also derive the general features of the U(2)-symmetric models required by the experimental bounds, in case of elementary and totally composite t R . An effect in the Zb-barb coupling, which can potentially allow for sizable deviations in Z→b-barb decay parameters without modifying flavour physics observables, is identified. We also present the analysis of the mixed scenario, where the top quark mass is generated due to Partial Compositeness while the light quark masses are Technicolor-like.

  10. New models for success emerge for US natural gas industry

    International Nuclear Information System (INIS)

    Addy, W.M.; Hutchinson, R.A.

    1994-01-01

    Very few companies in the US natural gas industry are confident in their ability to compete effectively in the brave new world of deregulation. Boston Consulting Group recently conducted an internal study to help the industry think about its future and identify models for success in this new environment. The authors examined the historical performance of 800 companies using several shareholder-value indicators, including cash-flow returns on investment, a measure of cash returns on cash invested that correlates closely to share price. Based on that review and discussions with investment managers and industry analysts, the authors were able to focus on a handful of companies that actually have thrived and created value against the difficult landscape of the past decade. Interviews with their senior executives provided important strategic and operational insights

  11. Modeling Gene-Environment Interactions With Quasi-Natural Experiments.

    Science.gov (United States)

    Schmitz, Lauren; Conley, Dalton

    2017-02-01

    This overview develops new empirical models that can effectively document Gene × Environment (G×E) interactions in observational data. Current G×E studies are often unable to support causal inference because they use endogenous measures of the environment or fail to adequately address the nonrandom distribution of genes across environments, confounding estimates. Comprehensive measures of genetic variation are incorporated into quasi-natural experimental designs to exploit exogenous environmental shocks or isolate variation in environmental exposure to avoid potential confounders. In addition, we offer insights from population genetics that improve upon extant approaches to address problems from population stratification. Together, these tools offer a powerful way forward for G×E research on the origin and development of social inequality across the life course. © 2015 Wiley Periodicals, Inc.

  12. Modeling of information flows in natural gas storage facility

    Science.gov (United States)

    Ranjbari, Leyla; Bahar, Arifah; Aziz, Zainal Abdul

    2013-09-01

    The paper considers the natural-gas storage valuation based on the information-based pricing framework of Brody-Hughston-Macrina (BHM). As opposed to many studies which the associated filtration is considered pre-specified, this work tries to construct the filtration in terms of the information provided to the market. The value of the storage is given by the sum of the discounted expectations of the cash flows under risk-neutral measure, conditional to the constructed filtration with the Brownian bridge noise term. In order to model the flow of information about the cash flows, we assume the existence of a fixed pricing kernel with liquid, homogenous and incomplete market without arbitrage.

  13. Modeling natural emissions in the Community Multiscale Air Quality (CMAQ model – Part 2: Modifications for simulating natural emissions

    Directory of Open Access Journals (Sweden)

    S. F. Mueller

    2011-01-01

    Full Text Available The Community Multiscale Air Quality (CMAQ model version 4.6 has been revised with regard to the representation of chlorine (HCl, ClNO2 and sulfur (dimethylsulfide, or DMS, and H2S, and evaluated against observations and earlier published models. Chemistry parameterizations were based on published reaction kinetic data and a recently developed cloud chemistry model that includes heterogeneous reactions of organic sulfur compounds. Evaluation of the revised model was conducted using a recently enhanced data base of natural emissions that includes ocean and continental sources of DMS, H2S, chlorinated gases and lightning NOx for the continental United States and surrounding regions. Results using 2002 meteorology and emissions indicated that most simulated "natural" (plus background chemical and aerosol species exhibit the expected seasonal variations at the surface. Ozone exhibits a winter and early spring maximum consistent with ozone data and an earlier published model. Ozone distributions reflect the influences of atmospheric dynamics and pollutant background levels imposed on the CMAQ simulation by boundary conditions derived from a global model. A series of model experiments reveals that the consideration of gas-phase organic sulfur chemistry leads to sulfate aerosol increases over most of the continental United States. Cloud chemistry parameterization changes result in widespread decreases in SO2 across the modeling domain and both increases and decreases in sulfate. Most cloud-mediated sulfate increases occurred mainly over the Pacific Ocean (up to about 0.1 μg m−3 but also over and downwind from the Gulf of Mexico (including parts of the eastern US. Geographic variations in simulated SO2 and sulfate are due to the link between DMS/H2S and their byproduct SO2, the heterogeneity of cloud cover and precipitation (precipitating clouds act as

  14. Using natural laboratories and modeling to decipher lithospheric rheology

    Science.gov (United States)

    Sobolev, Stephan

    2013-04-01

    Rheology is obviously important for geodynamic modeling but at the same time rheological parameters appear to be least constrained. Laboratory experiments give rather large ranges of rheological parameters and their scaling to nature is not entirely clear. Therefore finding rheological proxies in nature is very important. One way to do that is finding appropriate values of rheological parameter by fitting models to the lithospheric structure in the highly deformed regions where lithospheric structure and geologic evolution is well constrained. Here I will present two examples of such studies at plate boundaries. One case is the Dead Sea Transform (DST) that comprises a boundary between African and Arabian plates. During the last 15- 20 Myr more than 100 km of left lateral transform displacement has been accumulated on the DST and about 10 km thick Dead Sea Basin (DSB) was formed in the central part of the DST. Lithospheric structure and geological evolution of DST and DSB is rather well constrained by a number of interdisciplinary projects including DESERT and DESIRE projects leaded by the GFZ Potsdam. Detailed observations reveal apparently contradictory picture. From one hand widespread igneous activity, especially in the last 5 Myr, thin (60-80 km) lithosphere constrained from seismic data and absence of seismicity below the Moho, seem to be quite natural for this tectonically active plate boundary. However, surface heat flow of less than 50-60mW/m2 and deep seismicity in the lower crust ( deeper than 20 km) reported for this region are apparently inconsistent with the tectonic settings specific for an active continental plate boundary and with the crustal structure of the DSB. To address these inconsistencies which comprise what I call the "DST heat-flow paradox", a 3D numerical thermo-mechanical model was developed operating with non-linear elasto-visco-plastic rheology of the lithosphere. Results of the numerical experiments show that the entire set of

  15. Modeling of Marine Natural Hazards in the Lesser Antilles

    Science.gov (United States)

    Zahibo, Narcisse; Nikolkina, Irina; Pelinovsky, Efim

    2010-05-01

    The Caribbean Sea countries are often affected by various marine natural hazards: hurricanes and cyclones, tsunamis and flooding. The historical data of marine natural hazards for the Lesser Antilles and specially, for Guadeloupe are presented briefly. Numerical simulation of several historical tsunamis in the Caribbean Sea (1755 Lisbon trans-Atlantic tsunami, 1867 Virgin Island earthquake tsunami, 2003 Montserrat volcano tsunami) are performed within the framework of the nonlinear-shallow theory. Numerical results demonstrate the importance of the real bathymetry variability with respect to the direction of propagation of tsunami wave and its characteristics. The prognostic tsunami wave height distribution along the Caribbean Coast is computed using various forms of seismic and hydrodynamics sources. These results are used to estimate the far-field potential for tsunami hazards at coastal locations in the Caribbean Sea. The nonlinear shallow-water theory is also applied to model storm surges induced by tropical cyclones, in particular, cyclones "Lilli" in 2002 and "Dean" in 2007. Obtained results are compared with observed data. The numerical models have been tested against known analytical solutions of the nonlinear shallow-water wave equations. Obtained results are described in details in [1-7]. References [1] N. Zahibo and E. Pelinovsky, Natural Hazards and Earth System Sciences, 1, 221 (2001). [2] N. Zahibo, E. Pelinovsky, A. Yalciner, A. Kurkin, A. Koselkov and A. Zaitsev, Oceanologica Acta, 26, 609 (2003). [3] N. Zahibo, E. Pelinovsky, A. Kurkin and A. Kozelkov, Science Tsunami Hazards. 21, 202 (2003). [4] E. Pelinovsky, N. Zahibo, P. Dunkley, M. Edmonds, R. Herd, T. Talipova, A. Kozelkov and I. Nikolkina, Science of Tsunami Hazards, 22, 44 (2004). [5] N. Zahibo, E. Pelinovsky, E. Okal, A. Yalciner, C. Kharif, T. Talipova and A. Kozelkov, Science of Tsunami Hazards, 23, 25 (2005). [6] N. Zahibo, E. Pelinovsky, T. Talipova, A. Rabinovich, A. Kurkin and I

  16. Entropy in the Tangled Nature Model of Evolution

    Directory of Open Access Journals (Sweden)

    Ty N. F. Roach

    2017-04-01

    Full Text Available Applications of entropy principles to evolution and ecology are of tantamount importance given the central role spatiotemporal structuring plays in both evolution and ecological succession. We obtain here a qualitative interpretation of the role of entropy in evolving ecological systems. Our interpretation is supported by mathematical arguments using simulation data generated by the Tangled Nature Model (TNM, a stochastic model of evolving ecologies. We define two types of configurational entropy and study their empirical time dependence obtained from the data. Both entropy measures increase logarithmically with time, while the entropy per individual decreases in time, in parallel with the growth of emergent structures visible from other aspects of the simulation. We discuss the biological relevance of these entropies to describe niche space and functional space of ecosystems, as well as their use in characterizing the number of taxonomic configurations compatible with different niche partitioning and functionality. The TNM serves as an illustrative example of how to calculate and interpret these entropies, which are, however, also relevant to real ecosystems, where they can be used to calculate the number of functional and taxonomic configurations that an ecosystem can realize.

  17. Review of Modelling Approaches for Developing Virtual Natural Lighting Solutions

    NARCIS (Netherlands)

    Mangkuto, R.A.; Ochoa Morales, C.E.; Aries, M.B.C.; Loenen, van E.J.; Hensen, J.L.M.

    2011-01-01

    Several studies have shown that natural light is preferred over electrical lighting in built environments. It has positive effects on user satisfaction, health, and energy saving. However, natural light is limited by time and space. A possible solution is to apply the new concept of virtual natural

  18. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Michael L.; Brown, Raymon L.; Civan, Frauk; Hughes, Richard G.

    2001-08-15

    Research continues on characterizing and modeling the behavior of naturally fractured reservoir systems. Work has progressed on developing techniques for estimating fracture properties from seismic and well log data, developing naturally fractured wellbore models, and developing a model to characterize the transfer of fluid from the matrix to the fracture system for use in the naturally fractured reservoir simulator.

  19. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  20. Natural gas transmission and distribution model of the National Energy Modeling System

    International Nuclear Information System (INIS)

    1997-02-01

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of Integrated Analysis and Forecasting of the Energy Information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. From 1982 through 1993, the Intermediate Future Forecasting System (IFFS) was used by the EIA for its analyses, and the Gas Analysis Modeling System (GAMS) was used within IFFS to represent natural gas markets. Prior to 1982, the Midterm Energy Forecasting System (MEFS), also referred to as the Project Independence Evaluation System (PIES), was employed. NEMS was developed to enhance and update EIA's modeling capability by internally incorporating models of energy markets that had previously been analyzed off-line. In addition, greater structural detail in NEMS permits the analysis of a broader range of energy issues. The time horizon of NEMS is the midterm period (i.e., through 2015). In order to represent the regional differences in energy markets, the component models of NEMS function at regional levels appropriate for the markets represented, with subsequent aggregation/disaggregation to the Census Division level for reporting purposes

  1. Natural gas transmission and distribution model of the National Energy Modeling System

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-02-01

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of Integrated Analysis and Forecasting of the Energy Information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. From 1982 through 1993, the Intermediate Future Forecasting System (IFFS) was used by the EIA for its analyses, and the Gas Analysis Modeling System (GAMS) was used within IFFS to represent natural gas markets. Prior to 1982, the Midterm Energy Forecasting System (MEFS), also referred to as the Project Independence Evaluation System (PIES), was employed. NEMS was developed to enhance and update EIA`s modeling capability by internally incorporating models of energy markets that had previously been analyzed off-line. In addition, greater structural detail in NEMS permits the analysis of a broader range of energy issues. The time horizon of NEMS is the midterm period (i.e., through 2015). In order to represent the regional differences in energy markets, the component models of NEMS function at regional levels appropriate for the markets represented, with subsequent aggregation/disaggregation to the Census Division level for reporting purposes.

  2. Evaluation and hydrological modelization in the natural hazard prevention

    International Nuclear Information System (INIS)

    Pla Sentis, Ildefonso

    2011-01-01

    Soil degradation affects negatively his functions as a base to produce food, to regulate the hydrological cycle and the environmental quality. All over the world soil degradation is increasing partly due to lacks or deficiencies in the evaluations of the processes and causes of this degradation on each specific situation. The processes of soil physical degradation are manifested through several problems as compaction, runoff, hydric and Eolic erosion, landslides with collateral effects in situ and in the distance, often with disastrous consequences as foods, landslides, sedimentations, droughts, etc. These processes are frequently associated to unfavorable changes into the hydrologic processes responsible of the water balance and soil hydric regimes, mainly derived to soil use changes and different management practices and climatic changes. The evaluation of these processes using simple simulation models; under several scenarios of climatic change, soil properties and land use and management; would allow to predict the occurrence of this disastrous processes and consequently to select and apply the appropriate practices of soil conservation to eliminate or reduce their effects. This simulation models require, as base, detailed climatic information and hydrologic soil properties data. Despite of the existence of methodologies and commercial equipment (each time more sophisticated and precise) to measure the different physical and hydrological soil properties related with degradation processes, most of them are only applicable under really specific or laboratory conditions. Often indirect methodologies are used, based on relations or empiric indexes without an adequate validation, that often lead to expensive mistakes on the evaluation of soil degradation processes and their effects on natural disasters. It could be preferred simple field methodologies, direct and adaptable to different soil types and climates and to the sample size and the spatial variability of the

  3. Understanding the molecular mechanisms underlying the effects of light intensity on flavonoid production by RNA-seq analysis in Epimedium pseudowushanense B.L.Guo.

    Directory of Open Access Journals (Sweden)

    Junqian Pan

    Full Text Available Epimedium pseudowushanense B.L.Guo, a light-demanding shade herb, is used in traditional medicine to increase libido and strengthen muscles and bones. The recognition of the health benefits of Epimedium has increased its market demand. However, its resource recycling rate is low and environmentally dependent. Furthermore, its natural sources are endangered, further increasing prices. Commercial culture can address resource constraints of it.Understanding the effects of environmental factors on the production of its active components would improve the technology for cultivation and germplasm conservation. Here, we studied the effects of light intensities on the flavonoid production and revealed the molecular mechanism using RNA-seq analysis. Plants were exposed to five levels of light intensity through the periods of germination to flowering, the flavonoid contents were measured using HPLC. Quantification of epimedin A, epimedin B, epimedin C, and icariin showed that the flavonoid contents varied with different light intensity levels. And the largest amount of epimedin C was produced at light intensity level 4 (I4. Next, the leaves under the treatment of three light intensity levels ("L", "M" and "H" with the largest differences in the flavonoid content, were subjected to RNA-seq analysis. Transcriptome reconstruction identified 43,657 unigenes. All unigene sequences were annotated by searching against the Nr, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes (KEGG databases. In total, 4008, 5260, and 3591 significant differentially expressed genes (DEGs were identified between the groups L vs. M, M vs. H and L vs. H. Particularly, twenty-one full-length genes involved in flavonoid biosynthesis were identified. The expression levels of the flavonol synthase, chalcone synthase genes were strongly associated with light-induced flavonoid abundance with the highest expression levels found in the H group. Furthermore, 65 transcription factors

  4. Understanding the molecular mechanisms underlying the effects of light intensity on flavonoid production by RNA-seq analysis in Epimedium pseudowushanense B.L.Guo.

    Science.gov (United States)

    Pan, Junqian; Chen, Haimei; Guo, Baolin; Liu, Chang

    2017-01-01

    Epimedium pseudowushanense B.L.Guo, a light-demanding shade herb, is used in traditional medicine to increase libido and strengthen muscles and bones. The recognition of the health benefits of Epimedium has increased its market demand. However, its resource recycling rate is low and environmentally dependent. Furthermore, its natural sources are endangered, further increasing prices. Commercial culture can address resource constraints of it.Understanding the effects of environmental factors on the production of its active components would improve the technology for cultivation and germplasm conservation. Here, we studied the effects of light intensities on the flavonoid production and revealed the molecular mechanism using RNA-seq analysis. Plants were exposed to five levels of light intensity through the periods of germination to flowering, the flavonoid contents were measured using HPLC. Quantification of epimedin A, epimedin B, epimedin C, and icariin showed that the flavonoid contents varied with different light intensity levels. And the largest amount of epimedin C was produced at light intensity level 4 (I4). Next, the leaves under the treatment of three light intensity levels ("L", "M" and "H") with the largest differences in the flavonoid content, were subjected to RNA-seq analysis. Transcriptome reconstruction identified 43,657 unigenes. All unigene sequences were annotated by searching against the Nr, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. In total, 4008, 5260, and 3591 significant differentially expressed genes (DEGs) were identified between the groups L vs. M, M vs. H and L vs. H. Particularly, twenty-one full-length genes involved in flavonoid biosynthesis were identified. The expression levels of the flavonol synthase, chalcone synthase genes were strongly associated with light-induced flavonoid abundance with the highest expression levels found in the H group. Furthermore, 65 transcription factors, including 31

  5. Microstrip natural wave spectrum mathematical model using partial inversion method

    International Nuclear Information System (INIS)

    Pogarsky, S.A.; Litvinenko, L.N.; Prosvirnin, S.L.

    1995-01-01

    It is generally agreed that both microstrip lines itself and different discontinuities based on microstrips are the most difficult problem for accurate electrodynamic analysis. Over the last years much has been published about principles and accurate (or full wave) methods of microstrip lines investigations. The growing interest for this problem may be explained by the microstrip application in the millimeter-wave range for purpose of realizing interconnects and a variety of passive components. At these higher operating rating frequencies accurate component modeling becomes more critical. A creation, examination and experimental verification of the accurate method for planar electrodynamical structures natural wave spectrum investigations are the objects of this manuscript. The moment method with partial inversion operator method using may be considered as a basical way for solving this problem. This method is outlook for accurate analysis of different planar discontinuities in microstrip: such as step discontinuities, microstrip turns, Y- and X-junctions and etc., substrate space steps dielectric constants and other anisotropy types

  6. Spectrally-consistent regularization modeling of turbulent natural convection flows

    International Nuclear Information System (INIS)

    Trias, F Xavier; Gorobets, Andrey; Oliva, Assensi; Verstappen, Roel

    2012-01-01

    The incompressible Navier-Stokes equations constitute an excellent mathematical modelization of turbulence. Unfortunately, attempts at performing direct simulations are limited to relatively low-Reynolds numbers because of the almost numberless small scales produced by the non-linear convective term. Alternatively, a dynamically less complex formulation is proposed here. Namely, regularizations of the Navier-Stokes equations that preserve the symmetry and conservation properties exactly. To do so, both convective and diffusive terms are altered in the same vein. In this way, the convective production of small scales is effectively restrained whereas the modified diffusive term introduces a hyperviscosity effect and consequently enhances the destruction of small scales. In practice, the only additional ingredient is a self-adjoint linear filter whose local filter length is determined from the requirement that vortex-stretching must stop at the smallest grid scale. In the present work, the performance of the above-mentioned recent improvements is assessed through application to turbulent natural convection flows by means of comparison with DNS reference data.

  7. Modelling the costs of natural hazards in games

    Science.gov (United States)

    Bostenaru-Dan, M.

    2012-04-01

    City are looked for today, including a development at the University of Torino called SimTorino, which simulates the development of the city in the next 20 years. The connection to another games genre as video games, the board games, will be investigated, since there are games on construction and reconstruction of a cathedral and its tower and a bridge in an urban environment of the middle ages based on the two novels of Ken Follett, "Pillars of the Earth" and "World Without End" and also more recent games, such as "Urban Sprawl" or the Romanian game "Habitat", dealing with the man-made hazard of demolition. A review of these games will be provided based on first hand playing experience. In games like "World without End" or "Pillars of the Earth", just like in the recently popular games of Zynga on social networks, construction management is done through providing "building" an item out of stylised materials, such as "stone", "sand" or more specific ones as "nail". Such approach could be used also for retrofitting buildings for earthquakes, in the series of "upgrade", not just for extension as it is currently in games, and this is what our research is about. "World without End" includes a natural disaster not so analysed today but which was judged by the author as the worst of manhood: the Black Death. The Black Death has effects and costs as well, not only modelled through action cards, but also on the built environment, by buildings remaining empty. On the other hand, games such as "Habitat" rely on role playing, which has been recently recognised as a way to bring games theory to decision making through the so-called contribution of drama, a way to solve conflicts through balancing instead of weighting, and thus related to Analytic Hierarchy Process. The presentation aims to also give hints on how to design a game for the problem of earthquake retrofit, translating the aims of the actors in such a process into role playing. Games are also employed in teaching of urban

  8. Capturing and Modeling Domain Knowledge Using Natural Language Processing Techniques

    National Research Council Canada - National Science Library

    Auger, Alain

    2005-01-01

    .... Initiated in 2004 at Defense Research and Development Canada (DRDC), the SACOT knowledge engineering research project is currently investigating, developing and validating innovative natural language processing (NLP...

  9. A model integrating social-cultural concepts of nature into frameworks of interaction between social and natural systems

    DEFF Research Database (Denmark)

    Muhar, Andreas; Raymond, Christopher M.; van den Born, Riyan J.G.

    2018-01-01

    relationship at both individual and collective levels. We highlight the relevance of individual and collective understandings of the human-nature relationship as influencing factors for environmental behaviour, which may be reflected in natural resource management conflicts, and review the diversity......Existing frameworks for analysing interactions between social and natural systems (e.g. Social-Ecological Systems framework, Ecosystem Services concept) do not sufficiently consider and operationalize the dynamic interactions between people's values, attitudes and understandings of the human-nature....... Integrating this model into existing frameworks provides a tool for the exploration of how social-cultural concepts of nature interact with existing contexts to influence governance of social-ecological systems....

  10. Verification of Interactions between Silica and Epoxidized Squalene as a Model for Epoxidized Natural Rubber

    NARCIS (Netherlands)

    Kaewsakul, Wisut; Sahakaro, Kannika; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2014-01-01

    Unmodified squalene (Sq) and epoxidised squalene (ESq), as models for natural rubber and epoxidised natural rubber, were mixed with silica in a reactor at 140 – 145ºC, which corresponds to the optimal mixing dump temperature of silica-filled natural rubber or epoxidised natural rubber compounds. The

  11. Models of natural computation : gene assembly and membrane systems

    NARCIS (Netherlands)

    Brijder, Robert

    2008-01-01

    This thesis is concerned with two research areas in natural computing: the computational nature of gene assembly and membrane computing. Gene assembly is a process occurring in unicellular organisms called ciliates. During this process genes are transformed through cut-and-paste operations. We

  12. Opinion: The use of natural hazard modeling for decision making under uncertainty

    Science.gov (United States)

    David E. Calkin; Mike Mentis

    2015-01-01

    Decision making to mitigate the effects of natural hazards is a complex undertaking fraught with uncertainty. Models to describe risks associated with natural hazards have proliferated in recent years. Concurrently, there is a growing body of work focused on developing best practices for natural hazard modeling and to create structured evaluation criteria for complex...

  13. Handbook of nature-inspired and innovative computing integrating classical models with emerging technologies

    CERN Document Server

    2006-01-01

    As computing devices proliferate, demand increases for an understanding of emerging computing paradigms and models based on natural phenomena. This handbook explores the connection between nature-inspired and traditional computational paradigms. It presents computing paradigms and models based on natural phenomena.

  14. Biomimetics: using nature as an inspiring model for human innovation

    Science.gov (United States)

    Bar-Cohen, Yoseph

    2006-01-01

    The evolution of nature over 3.8 billion years led to the highly effective and power efficient biological mechanisms. Imitating these mechanisms offers enormous potentials for the improvement of our life and the tools we use.

  15. Conceptual geoinformation model of natural hazards risk assessment

    Science.gov (United States)

    Kulygin, Valerii

    2016-04-01

    Natural hazards are the major threat to safe interactions between nature and society. The assessment of the natural hazards impacts and their consequences is important in spatial planning and resource management. Today there is a challenge to advance our understanding of how socio-economical and climate changes will affect the frequency and magnitude of hydro-meteorological hazards and associated risks. However, the impacts from different types of natural hazards on various marine and coastal economic activities are not of the same type. In this study, the conceptual geomodel of risk assessment is presented to highlight the differentiation by the type of economic activities in extreme events risk assessment. The marine and coastal ecosystems are considered as the objects of management, on the one hand, and as the place of natural hazards' origin, on the other hand. One of the key elements in describing of such systems is the spatial characterization of their components. Assessment of ecosystem state is based on ecosystem indicators (indexes). They are used to identify the changes in time. The scenario approach is utilized to account for the spatio-temporal dynamics and uncertainty factors. Two types of scenarios are considered: scenarios of using ecosystem services by economic activities and scenarios of extreme events and related hazards. The reported study was funded by RFBR, according to the research project No. 16-35-60043 mol_a_dk.

  16. Catastrophes in nature and society mathematical modeling of complex systems

    CERN Document Server

    Khlebopros, Rem G; Fet, Abram I

    2007-01-01

    Many people are concerned about crises leading to disasters in nature, in social and economic life. The book offers a popular account of the causative mechanisms of critical states and breakdown in a broad range of natural and cultural systems - which obey the same laws - and thus makes the reader aware of the origin of catastrophic events and the ways to avoid and mitigate their negative consequences. The authors apply a single mathematical approach to investigate the revolt of cancer cells that destroy living organisms and population outbreaks that upset natural ecosystems, the balance between biosphere and global climate interfered lately by industry, the driving mechanisms of market and related economic and social phenomena, as well as the electoral system the proper use of which is an arduous accomplishment of democracy.

  17. A review of modelling the interaction between natural organic matter and metal cations

    International Nuclear Information System (INIS)

    Falck, W.E.

    1989-01-01

    This report reviews techniques available to model the interaction between natural organic matter (mainly fulvic and humic acids) and metal cations and protons. A comprehensive overview over the properties of natural organic matter is given and experimental techniques are presented briefly. Two major concepts of modelling have been identified: discrete ligand models and continuous distribution model. Different modelling approaches like Discrete Ligand Models (s.s.), Random-Structure Model, Affinity Spectra, Statistical Distribution Models, Continuous Stability Function Models and surface sorption models and their advantages/disadvantages are discussed. (author)

  18. Structural modeling of natural citrus products as potential cross ...

    African Journals Online (AJOL)

    There are four serotypes of Dengue virus and there are existing drugs used against specific serotype. There is no drug that is effective against all strains of this virus. In this research, bioinformatics tools were used to predict the affinity of natural ligands for the glycoprotein E of Dengue virus by considering the conserved ...

  19. The Living Dead: Transformative Experiences in Modelling Natural Selection

    Science.gov (United States)

    Petersen, Morten Rask

    2017-01-01

    This study considers how students change their coherent conceptual understanding of natural selection through a hands-on simulation. The results show that most students change their understanding. In addition, some students also underwent a transformative experience and used their new knowledge in a leisure time activity. These transformative…

  20. Natural variation of model mutant phenotypes in Ciona intestinalis.

    Directory of Open Access Journals (Sweden)

    Paolo Sordino

    Full Text Available BACKGROUND: The study of ascidians (Chordata, Tunicata has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. CONCLUSIONS/SIGNIFICANCE: Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity.

  1. Natural Variation of Model Mutant Phenotypes in Ciona intestinalis

    Science.gov (United States)

    Brown, Euan R.; Leccia, Nicola I.; Squarzoni, Paola; Tarallo, Raffaella; Alfano, Christian; Caputi, Luigi; D'Ambrosio, Palmira; Daniele, Paola; D'Aniello, Enrico; D'Aniello, Salvatore; Maiella, Sylvie; Miraglia, Valentina; Russo, Monia Teresa; Sorrenti, Gerarda; Branno, Margherita; Cariello, Lucio; Cirino, Paola; Locascio, Annamaria; Spagnuolo, Antonietta; Zanetti, Laura; Ristoratore, Filomena

    2008-01-01

    Background The study of ascidians (Chordata, Tunicata) has made a considerable contribution to our understanding of the origin and evolution of basal chordates. To provide further information to support forward genetics in Ciona intestinalis, we used a combination of natural variation and neutral population genetics as an approach for the systematic identification of new mutations. In addition to the significance of developmental variation for phenotype-driven studies, this approach can encompass important implications in evolutionary and population biology. Methodology/Principal Findings Here, we report a preliminary survey for naturally occurring mutations in three geographically interconnected populations of C. intestinalis. The influence of historical, geographical and environmental factors on the distribution of abnormal phenotypes was assessed by means of 12 microsatellites. We identified 37 possible mutant loci with stereotyped defects in embryonic development that segregate in a way typical of recessive alleles. Local populations were found to differ in genetic organization and frequency distribution of phenotypic classes. Conclusions/Significance Natural genetic polymorphism of C. intestinalis constitutes a valuable source of phenotypes for studying embryonic development in ascidians. Correlating genetic structure and the occurrence of abnormal phenotypes is a crucial focus for understanding the selective forces that shape natural finite populations, and may provide insights of great importance into the evolutionary mechanisms that generate animal diversity. PMID:18523552

  2. Paired structures in logical and semiotic models of natural language

    DEFF Research Database (Denmark)

    Rodríguez, J. Tinguaro; Franco, Camilo; Montero, Javier

    2014-01-01

    The evidence coming from cognitive psychology and linguistics shows that pairs of reference concepts (as e.g. good/bad, tall/short, nice/ugly, etc.) play a crucial role in the way we everyday use and understand natural languages in order to analyze reality and make decisions. Different situations...

  3. Modeling approaches to natural convection in porous media

    CERN Document Server

    Su, Yan

    2015-01-01

    This book provides an overview of the field of flow and heat transfer in porous medium and focuses on presentation of a generalized approach to predict drag and convective heat transfer within porous medium of arbitrary microscopic geometry, including reticulated foams and packed beds. Practical numerical methods to solve natural convection problems in porous media will be presented with illustrative applications for filtrations, thermal storage and solar receivers.

  4. Numerical modeling of shear stimulation in naturally fractured geothermal reservoirs

    OpenAIRE

    Ucar, Eren

    2018-01-01

    Shear-dilation-based hydraulic stimulations are conducted to create enhanced geothermal systems (EGS) from low permeable geothermal reservoirs, which are initially not amenable to energy production. Reservoir stimulations are done by injecting low-pressurized fluid into the naturally fractured formations. The injection aims to activate critically stressed fractures by decreasing frictional strength and ultimately cause a shear failure. The shear failure leads to a permanent ...

  5. A Statistical Model for Natural Gas Standardized Load Profiles

    Czech Academy of Sciences Publication Activity Database

    Brabec, Marek; Konár, Ondřej; Malý, Marek; Pelikán, Emil; Vondráček, Jiří

    2009-01-01

    Roč. 58, č. 1 (2009), s. 123-139 ISSN 0035-9254 R&D Projects: GA AV ČR 1ET400300513 Institutional research plan: CEZ:AV0Z10300504 Keywords : disaggregation * generalized additive models * multiplicative model * non-linear effects * segmentation * semiparametric regression model Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use Impact factor: 1.060, year: 2009

  6. Yukawa couplings and the nature of zero modes in the Skyrme model

    International Nuclear Information System (INIS)

    Kawarabayashi, K.

    1989-01-01

    Several issues related, directly or indirectly, to the Yukawa coupling in the Skyrme model are discussed. The authors try to shed a new light on the physical nature of the zero modes associated with translation (rotation) invariance of the model

  7. A model for cooling systems analysis under natural convection

    International Nuclear Information System (INIS)

    Santos, S.J. dos.

    1988-01-01

    The present work analyses thermosyphons and their non dimensional numbers. The mathematical model considers constant pressure, single-phase incompressible flow. It simulates both open and closed thermosyphons, and deals with heat sources like PWR cores of electrical heaters and cold sinks like heat exchangers or reservoirs. A computer code named STRATS was developed based on this model. (author)

  8. Dynamic Modeling of Natural Convection Solar Energy Flat Plate ...

    African Journals Online (AJOL)

    The analytical solutions to the dynamic model of an air-heating flat plate solar energy thermal collector were validated by direct measurement from a physical model constructed for that purpose, of the temperatures of the cover and absorber plates, the inlet and outlet fluids, and the ambient air from morning to evening for ...

  9. Nature of dynamical suppressions in the generalized Veneziano model

    International Nuclear Information System (INIS)

    Odorico, R.

    1976-05-01

    It is shown by explicit numerical calculations that of a class of coupling suppressions existing in the generalized Veneziano model, which have been recently used to interpret the psi data and other related phenomena, only a part can be attributed to the exponential growth with energy of the number of levels in the model. The remaining suppressions have a more direct dual origin

  10. Modelling methane emissions from natural wetlands by development and application of the TRIPLEX-GHG model

    Science.gov (United States)

    Zhu, Qing; Liu, Jinxun; Peng, C.; Chen, H.; Fang, X.; Jiang, H.; Yang, G.; Zhu, D.; Wang, W.; Zhou, X.

    2014-01-01

    A new process-based model TRIPLEX-GHG was developed based on the Integrated Biosphere Simulator (IBIS), coupled with a new methane (CH4) biogeochemistry module (incorporating CH4 production, oxidation, and transportation processes) and a water table module to investigate CH4 emission processes and dynamics that occur in natural wetlands. Sensitivity analysis indicates that the most sensitive parameters to evaluate CH4 emission processes from wetlands are r (defined as the CH4 to CO2 release ratio) and Q10 in the CH4 production process. These two parameters were subsequently calibrated to data obtained from 19 sites collected from approximately 35 studies across different wetlands globally. Being heterogeneously spatially distributed, r ranged from 0.1 to 0.7 with a mean value of 0.23, and the Q10 for CH4 production ranged from 1.6 to 4.5 with a mean value of 2.48. The model performed well when simulating magnitude and capturing temporal patterns in CH4 emissions from natural wetlands. Results suggest that the model is able to be applied to different wetlands under varying conditions and is also applicable for global-scale simulations.

  11. Modelling and control of natural convection in canned foods

    Science.gov (United States)

    Alvarez-Vazquez, L. J.; Martinez, A.

    1999-12-01

    In this paper we study mathematically an industrial problem related to sterilization processes involving heat transfer by natural convection. We give results of existence and regularity for the solution of this problem. We recast the whole problem as an optimal control problem with pointwise constraints on the state and the control in order to ensure the reduction of microorganism concentration and the retention of nutrients, and to save energy. Finally, we give results on existence of the optimal solution and optimality conditions for its characterization.

  12. A Parsimonious Bootstrap Method to Model Natural Inflow Energy Series

    Directory of Open Access Journals (Sweden)

    Fernando Luiz Cyrino Oliveira

    2014-01-01

    Full Text Available The Brazilian energy generation and transmission system is quite peculiar in its dimension and characteristics. As such, it can be considered unique in the world. It is a high dimension hydrothermal system with huge participation of hydro plants. Such strong dependency on hydrological regimes implies uncertainties related to the energetic planning, requiring adequate modeling of the hydrological time series. This is carried out via stochastic simulations of monthly inflow series using the family of Periodic Autoregressive models, PAR(p, one for each period (month of the year. In this paper it is shown the problems in fitting these models by the current system, particularly the identification of the autoregressive order “p” and the corresponding parameter estimation. It is followed by a proposal of a new approach to set both the model order and the parameters estimation of the PAR(p models, using a nonparametric computational technique, known as Bootstrap. This technique allows the estimation of reliable confidence intervals for the model parameters. The obtained results using the Parsimonious Bootstrap Method of Moments (PBMOM produced not only more parsimonious model orders but also adherent stochastic scenarios and, in the long range, lead to a better use of water resources in the energy operation planning.

  13. Modeling the Temporal Nature of Human Behavior for Demographics Prediction

    DEFF Research Database (Denmark)

    Felbo, Bjarke; Sundsøy, Pål; Pentland, Alex

    2017-01-01

    Mobile phone metadata is increasingly used for humanitarian purposes in developing countries as traditional data is scarce. Basic demographic information is however often absent from mobile phone datasets, limiting the operational impact of the datasets. For these reasons, there has been a growing...... interest in predicting demographic information from mobile phone metadata. Previous work focused on creating increasingly advanced features to be modeled with standard machine learning algorithms. We here instead model the raw mobile phone metadata directly using deep learning, exploiting the temporal...... on both age and gender prediction using only the temporal modality in mobile metadata. We finally validate our method on low activity users and evaluate the modeling assumptions....

  14. The Standard Model is Natural as Magnetic Gauge Theory

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2011-01-01

    matter. The absence of scalars in the electric theory indicates that the associated magnetic theory is free from quadratic divergences. Our novel solution to the Standard Model hierarchy problem leads also to a new insight on the mystery of the observed number of fundamental fermion generations......We suggest that the Standard Model can be viewed as the magnetic dual of a gauge theory featuring only fermionic matter content. We show this by first introducing a Pati-Salam like extension of the Standard Model and then relating it to a possible dual electric theory featuring only fermionic...

  15. LHC signals for singlet neutrinos from a natural warped seesaw mechanism. II

    Science.gov (United States)

    Agashe, Kaustubh; Du, Peizhi; Hong, Sungwoo

    2018-04-01

    A natural seesaw mechanism for obtaining the observed size of SM neutrino masses can arise in a warped extra-dimensional/composite Higgs framework. In a previous paper, we initiated the study of signals at the LHC for the associated ˜TeV mass SM singlet neutrinos, within a canonical model of S U (2 )L×S U (2 )R×U (1 )B-L (LR) symmetry in the composite sector, as motivated by consistency with the EW precision tests. Here, we investigate LHC signals in a different region of parameter space for the same model, where production of singlet neutrinos can occur from particles beyond those in the usual LR models. Specifically, we assume that the composite (B -L ) gauge boson is lighter than all the others in the EW sector. We show that the composite (B -L ) gauge boson can acquire a significant coupling to light quarks simply via mixing with elementary hypercharge gauge boson. Thus, the singlet neutrino can be pair-produced via decays of the(B -L ) gauge boson, without a charged current counterpart. Furthermore, there is no decay for the (B -L ) gauge boson directly into dibosons, unlike for the usual case of WR± and Z'. Independently of the above extension of the EW sector, we analyze production of singlet neutrinos in decays of composite partners of S U (2 )L doublet leptons, which are absent in the usual LR models. In turn, these doublet leptons can be produced in composite WL decays. We show that the 4 -5 σ signal can be achieved for both cases described above for the following spectrum with 3000 fb-1 luminosity: 2-2.5 TeV composite gauge bosons, 1 TeV composite doublet lepton (for the second case) and 500-750 GeV singlet neutrino.

  16. Modeling the natural convective flow of micropolar nanofluids

    KAUST Repository

    Bourantas, Georgios; Loukopoulos, Vassilios C.

    2014-01-01

    transfer from the heated wall and should not therefore be neglected when computing heat and fluid flow of micropolar fluids, as nanofluids. The validity of the proposed model is depicted by comparing the numerical results obtained with available

  17. Decline Curve Based Models for Predicting Natural Gas Well Performance

    OpenAIRE

    Kamari, Arash; Mohammadi, Amir H.; Lee, Moonyong; Mahmood, Tariq; Bahadori, Alireza

    2016-01-01

    The productivity of a gas well declines over its production life as cannot cover economic policies. To overcome such problems, the production performance of gas wells should be predicted by applying reliable methods to analyse the decline trend. Therefore, reliable models are developed in this study on the basis of powerful artificial intelligence techniques viz. the artificial neural network (ANN) modelling strategy, least square support vector machine (LSSVM) approach, adaptive neuro-fuzzy ...

  18. Natural vs. artificial groundwater recharge, quantification through inverse modeling

    Directory of Open Access Journals (Sweden)

    H. Hashemi

    2013-02-01

    Full Text Available Estimating the change in groundwater recharge from an introduced artificial recharge system is important in order to evaluate future water availability. This paper presents an inverse modeling approach to quantify the recharge contribution from both an ephemeral river channel and an introduced artificial recharge system based on floodwater spreading in arid Iran. The study used the MODFLOW-2000 to estimate recharge for both steady- and unsteady-state conditions. The model was calibrated and verified based on the observed hydraulic head in observation wells and model precision, uncertainty, and model sensitivity were analyzed in all modeling steps. The results showed that in a normal year without extreme events, the floodwater spreading system is the main contributor to recharge with 80% and the ephemeral river channel with 20% of total recharge in the studied area. Uncertainty analysis revealed that the river channel recharge estimation represents relatively more uncertainty in comparison to the artificial recharge zones. The model is also less sensitive to the river channel. The results show that by expanding the artificial recharge system, the recharge volume can be increased even for small flood events, while the recharge through the river channel increases only for major flood events.

  19. Stochastic Model for the Vocabulary Growth in Natural Languages

    Directory of Open Access Journals (Sweden)

    Martin Gerlach

    2013-05-01

    Full Text Available We propose a stochastic model for the number of different words in a given database which incorporates the dependence on the database size and historical changes. The main feature of our model is the existence of two different classes of words: (i a finite number of core words, which have higher frequency and do not affect the probability of a new word to be used, and (ii the remaining virtually infinite number of noncore words, which have lower frequency and, once used, reduce the probability of a new word to be used in the future. Our model relies on a careful analysis of the Google Ngram database of books published in the last centuries, and its main consequence is the generalization of Zipf’s and Heaps’ law to two-scaling regimes. We confirm that these generalizations yield the best simple description of the data among generic descriptive models and that the two free parameters depend only on the language but not on the database. From the point of view of our model, the main change on historical time scales is the composition of the specific words included in the finite list of core words, which we observe to decay exponentially in time with a rate of approximately 30 words per year for English.

  20. A quark model of baryons with natural flavor

    International Nuclear Information System (INIS)

    Forsyth, C.P.; Cutkowsky, R.E.

    1983-01-01

    We have fitted the masses and elastic widths of the S=0 baryons in the context of the QCD-improved quark shell model. All states in the N=0, 1, 2 and 3 harmonic oscillator bands have been included. Three models for the decay of these states have been studied, and it is concluded that the usual spectator model for the decays must be modified. Many resonances in the N=2 and 3 bands were found to decouple from the πN channel, supporting a previous solution to the missing resonance puzzle. No evidence has been found for the tensor force, while conflicting data exist for the 3-body spin orbit term. We also have found evidence that the contact force varies with band. The (56,1 - ) multiplet is lower than expected. (orig.)

  1. On the phase transition nature in compressible Ising models

    International Nuclear Information System (INIS)

    Ota, A.T.

    1985-01-01

    The phase transition phenomenon is analysed in a compressible ferromagnetic Ising model at null field, through the mean-field approximation. The model studied is d-dimensional under the magnetic point of view and one-dimensional under the elastic point of view. This is achieved keeping the compressive interactions among the ions and rejecting annealing forces completely. The exchange parameter J is linear and the elastic potential quadratic in relation to the microscopic shifts of the lattice. In the one-dimensional case, this model shows no phase transition. In the two-dimensional case, the role of the S i spin of the i-the ion is crucial: a) for spin 1/2 the transitions are of second order; b) for spin 1, desides the second order transitions there is a three-critical point and a first-order transitions line. (L.C.) [pt

  2. Maximally Symmetric Two Higgs Doublet Model with Natural Standard Model Alignment

    CERN Document Server

    Dev, P S Bhupal

    2014-01-01

    We study the Higgs mass spectrum as predicted by a Maximally Symmetric Two Higgs Doublet Model (MS-2HDM) potential based on the SO(5) group, softly broken by bilinear Higgs mass terms. We show that the lightest Higgs sector resulting from this MS-2HDM becomes naturally aligned with that of the Standard Model (SM), independently of the charged Higgs boson mass and $\\tan \\beta$. In the context of Type-II 2HDM, SO(5) is the simplest of the three possible symmetry realizations of the scalar potential that can naturally lead to the SM alignment. Nevertheless, renormalization group effects due to the hypercharge gauge coupling $g'$ and third-generation Yukawa couplings may break sizeably this SM alignment, along with the custodial symmetry inherited by the SO(5) group. Using the current Higgs signal strength data from the LHC, which disfavour large deviations from the SM alignment limit, we derive lower mass bounds on the heavy Higgs sector as a function of $\\tan\\beta$, which can be stronger than the existing limit...

  3. Model based on diffuse logic for the construction of indicators of urban vulnerability in natural phenomena

    International Nuclear Information System (INIS)

    Garcia L, Carlos Eduardo; Hurtado G, Jorge Eduardo

    2003-01-01

    Upon considering the vulnerability of a urban system in a holistic way and taking into account some natural, technological and social factors, a model based upon a system of fuzzy logic, allowing to estimate the vulnerability of any system under natural phenomena potentially catastrophic is proposed. The model incorporates quantitative and qualitative variables in a dynamic system, in which variations in one of them have a positive or negative impact over the rest. An urban system model and an indicator model to determine the vulnerability due to natural phenomena were designed

  4. Mechanistic CHF modeling for natural circulation applications in SMR

    Energy Technology Data Exchange (ETDEWEB)

    Luitjens, Jeffrey [Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, 3451 SW Jefferson Way, Corvallis, OR 97331 (United States); Wu, Qiao, E-mail: qiao.wu@oregonstate.edu [Department of Nuclear Engineering and Radiation Health Physics, Oregon State University, 3451 SW Jefferson Way, Corvallis, OR 97331 (United States); Greenwood, Scott; Corradini, Michael [Department of Engineering Physics, University of Wisconsin, 1415 Engineering Drive, Madison, WI 53706 (United States)

    2016-12-15

    A mechanistic critical heat flux correlation has been developed for a wide range of operating conditions which include low mass fluxes of 540–890 kg/m{sup 2}-s, high pressures of 12–13 MPa, and critical heat fluxes of 835–1100 kW/m{sup 2}. Eleven experimental data points have been collected over these conditions to inform the development of the model using bundle geometry. Errors of within 15% have been obtained with the proposed model for predicting the critical heat flux value, location, and critical pin power for a non-uniform heat flux applied to a 2 × 2 bundle configuration.

  5. Affinity labelling in situ of the bL12 protein on E. coli 70S ribosomes by means of a tRNA dialdehyde derivative.

    Science.gov (United States)

    Hountondji, Codjo; Créchet, Jean-Bernard; Le Caër, Jean-Pierre; Lancelot, Véronique; Cognet, Jean A H; Baouz, Soria

    2017-12-01

    In this report, we have used periodate-oxidized tRNA (tRNAox) as an affinity laleling reagent to demonstrate that: (i) the bL12 protein contacts the CCA-arm of P-site bound tRNA on the Escherichia coli 70S ribosomes; (ii) the stoichiometry of labelling is one molecule of tRNAox bound to one polypeptide chain of endogenous bL12; (iii) cross-linking in situ of bL12 with tRNAox on the ribosomes provokes the loss of activity; (iv) intact tRNA protects bL12 in the 70S ribosomes against cross-linking with tRNAox; (v) both tRNAox and pyridoxal 5'-phosphate (PLP) compete for the same or for proximal cross-linking site(s) on bL12 inside the ribosome; (vi) the stoichiometry of cross-linking of PLP to the recombinant E. coli bL12 protein is one molecule of PLP covalently bound per polypeptide chain; (vii) the amino acid residue of recombinant bL12 cross-linked with PLP is Lys-65; (viii) Lys-65 of E. coli bL12 corresponds to Lys-53 of eL42 which was previously shown to cross-link with P-site bound tRNAox on human 80S ribosomes in situ; (ix) finally, E. coli bL12 and human eL42 proteins display significant primary structure similarities, which argues for evolutionary conservation of these two proteins located at the tRNA-CCA binding site on eubacterial and eukaryal ribosomes. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  6. Decline curve based models for predicting natural gas well performance

    Directory of Open Access Journals (Sweden)

    Arash Kamari

    2017-06-01

    Full Text Available The productivity of a gas well declines over its production life as cannot cover economic policies. To overcome such problems, the production performance of gas wells should be predicted by applying reliable methods to analyse the decline trend. Therefore, reliable models are developed in this study on the basis of powerful artificial intelligence techniques viz. the artificial neural network (ANN modelling strategy, least square support vector machine (LSSVM approach, adaptive neuro-fuzzy inference system (ANFIS, and decision tree (DT method for the prediction of cumulative gas production as well as initial decline rate multiplied by time as a function of the Arps' decline curve exponent and ratio of initial gas flow rate over total gas flow rate. It was concluded that the results obtained based on the models developed in current study are in satisfactory agreement with the actual gas well production data. Furthermore, the results of comparative study performed demonstrates that the LSSVM strategy is superior to the other models investigated for the prediction of both cumulative gas production, and initial decline rate multiplied by time.

  7. Developing Models to Forcast Sales of Natural Christmas Trees

    Science.gov (United States)

    Lawrence D. Garrett; Thomas H. Pendleton

    1977-01-01

    A study of practices for marketing Christmas trees in Winston-Salem, North Carolina, and Denver, Colorado, revealed that such factors as retail lot competition, tree price, consumer traffic, and consumer income were very important in determining a particular retailer's sales. Analyses of 4 years of market data were used in developing regression models for...

  8. A Statistical Model for the Estimation of Natural Gas Consumption

    Czech Academy of Sciences Publication Activity Database

    Vondráček, Jiří; Pelikán, Emil; Konár, Ondřej; Čermáková, Jana; Eben, Kryštof; Malý, Marek; Brabec, Marek

    2008-01-01

    Roč. 85, c. 5 (2008), s. 362-370 ISSN 0306-2619 R&D Projects: GA AV ČR 1ET400300513 Institutional research plan: CEZ:AV0Z10300504 Keywords : nonlinear regression * gas consumption modeling Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.371, year: 2008

  9. A hierarchical probabilistic model for rapid object categorization in natural scenes.

    Directory of Open Access Journals (Sweden)

    Xiaofu He

    Full Text Available Humans can categorize objects in complex natural scenes within 100-150 ms. This amazing ability of rapid categorization has motivated many computational models. Most of these models require extensive training to obtain a decision boundary in a very high dimensional (e.g., ∼6,000 in a leading model feature space and often categorize objects in natural scenes by categorizing the context that co-occurs with objects when objects do not occupy large portions of the scenes. It is thus unclear how humans achieve rapid scene categorization.To address this issue, we developed a hierarchical probabilistic model for rapid object categorization in natural scenes. In this model, a natural object category is represented by a coarse hierarchical probability distribution (PD, which includes PDs of object geometry and spatial configuration of object parts. Object parts are encoded by PDs of a set of natural object structures, each of which is a concatenation of local object features. Rapid categorization is performed as statistical inference. Since the model uses a very small number (∼100 of structures for even complex object categories such as animals and cars, it requires little training and is robust in the presence of large variations within object categories and in their occurrences in natural scenes. Remarkably, we found that the model categorized animals in natural scenes and cars in street scenes with a near human-level performance. We also found that the model located animals and cars in natural scenes, thus overcoming a flaw in many other models which is to categorize objects in natural context by categorizing contextual features. These results suggest that coarse PDs of object categories based on natural object structures and statistical operations on these PDs may underlie the human ability to rapidly categorize scenes.

  10. Activity measurement and effective dose modelling of natural radionuclides in building material

    International Nuclear Information System (INIS)

    Maringer, F.J.; Baumgartner, A.; Rechberger, F.; Seidel, C.; Stietka, M.

    2013-01-01

    In this paper the assessment of natural radionuclides' activity concentration in building materials, calibration requirements and related indoor exposure dose models is presented. Particular attention is turned to specific improvements in low-level gamma-ray spectrometry to determine the activity concentration of necessary natural radionuclides in building materials with adequate measurement uncertainties. Different approaches for the modelling of the effective dose indoor due to external radiation resulted from natural radionuclides in building material and results of actual building material assessments are shown. - Highlights: • Dose models for indoor radiation exposure due to natural radionuclides in building materials. • Strategies and methods in radionuclide metrology, activity measurement and dose modelling. • Selection of appropriate parameters in radiation protection standards for building materials. • Scientific-based limitations of indoor exposure due to natural radionuclides in building materials

  11. Improvement of Endurance of DMD Animal Model Using Natural Polyphenols

    Directory of Open Access Journals (Sweden)

    Clementina Sitzia

    2015-01-01

    Full Text Available Duchenne muscular dystrophy (DMD, the most common form of muscular dystrophy, is characterized by muscular wasting caused by dystrophin deficiency that ultimately ends in force reduction and premature death. In addition to primary genetic defect, several mechanisms contribute to DMD pathogenesis. Recently, antioxidant supplementation was shown to be effective in the treatment of multiple diseases including muscular dystrophy. Different mechanisms were hypothesized such as reduced hydroxyl radicals, nuclear factor-κB deactivation, and NO protection from inactivation. Following these promising evidences, we investigated the effect of the administration of a mix of dietary natural polyphenols (ProAbe on dystrophic mdx mice in terms of muscular architecture and functionality. We observed a reduction of muscle fibrosis deposition and myofiber necrosis together with an amelioration of vascularization. More importantly, the recovery of the morphological features of dystrophic muscle leads to an improvement of the endurance of treated dystrophic mice. Our data confirmed that ProAbe-based diet may represent a strategy to coadjuvate the treatment of DMD.

  12. Tribology studies of the natural knee using an animal model in a new whole joint natural knee simulator.

    Science.gov (United States)

    Liu, Aiqin; Jennings, Louise M; Ingham, Eileen; Fisher, John

    2015-09-18

    The successful development of early-stage cartilage and meniscus repair interventions in the knee requires biomechanical and biotribological understanding of the design of the therapeutic interventions and their tribological function in the natural joint. The aim of this study was to develop and validate a porcine knee model using a whole joint knee simulator for investigation of the tribological function and biomechanical properties of the natural knee, which could then be used to pre-clinically assess the tribological performance of cartilage and meniscal repair interventions prior to in vivo studies. The tribological performance of standard artificial bearings in terms of anterior-posterior (A/P) shear force was determined in a newly developed six degrees of freedom tribological joint simulator. The porcine knee model was then developed and the tribological properties in terms of shear force measurements were determined for the first time for three levels of biomechanical constraints including A/P constrained, spring force semi-constrained and A/P unconstrained conditions. The shear force measurements showed higher values under the A/P constrained condition (predominantly sliding motion) compared to the A/P unconstrained condition (predominantly rolling motion). This indicated that the shear force simulation model was able to differentiate between tribological behaviours when the femoral and tibial bearing was constrained to slide or/and roll. Therefore, this porcine knee model showed the potential capability to investigate the effect of knee structural, biomechanical and kinematic changes, as well as different cartilage substitution therapies on the tribological function of natural knee joints. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Factoring variations in natural images with deep Gaussian mixture models

    OpenAIRE

    van den Oord, Aäron; Schrauwen, Benjamin

    2014-01-01

    Generative models can be seen as the swiss army knives of machine learning, as many problems can be written probabilistically in terms of the distribution of the data, including prediction, reconstruction, imputation and simulation. One of the most promising directions for unsupervised learning may lie in Deep Learning methods, given their success in supervised learning. However, one of the cur- rent problems with deep unsupervised learning methods, is that they often are harder to scale. As ...

  14. Direct and indirect signals of natural composite Higgs models

    Science.gov (United States)

    Niehoff, Christoph; Stangl, Peter; Straub, David M.

    2016-01-01

    We present a comprehensive numerical analysis of a four-dimensional model with the Higgs as a composite pseudo-Nambu-Goldstone boson that features a calculable Higgs potential and protective custodial and flavour symmetries to reduce electroweak fine-tuning. We employ a novel numerical technique that allows us for the first time to study constraints from radiative electroweak symmetry breaking, Higgs physics, electroweak precision tests, flavour physics, and direct LHC bounds on fermion and vector boson resonances in a single framework. We consider four different flavour symmetries in the composite sector, one of which we show to not be viable anymore in view of strong precision constraints. In the other cases, all constraints can be passed with a sub-percent electroweak fine-tuning. The models can explain the excesses recently observed in WW, WZ, Wh and ℓ + ℓ - resonance searches by ATLAS and CMS and the anomalies in angular observables and branching ratios of rare semi-leptonic B decays observed by LHCb. Solving the B physics anomalies predicts the presence of a dijet or toverline{t} resonance around 1 TeV just below the sensitivity of LHC run 1. We discuss the prospects to probe the models at run 2 of the LHC. As a side product, we identify several gaps in the searches for vector-like quarks at hadron colliders, that could be closed by reanalyzing existing LHC data.

  15. Quantifying the 'naturalness' of the curvaton model

    Energy Technology Data Exchange (ETDEWEB)

    Lerner, Rose N. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Helsinki Institute of Physics (Finland); Melville, Scott [Helsinki Institute of Physics (Finland)

    2014-02-15

    We investigate the probability of obtaining an observable curvature perturbation, using as an example the minimal curvaton-Higgs (MCH) model. We determine 'probably observable' and 'probably excluded' regions of parameter space assuming generic initial conditions and applying a stochastic approach for the curvaton's evolution during inflation. Inflation is assumed to last longer than the N{sub obs}≅55 observable e-folds, and the total number of e-folds of inflation determines the particular ranges of parameters that are probable. For the MCH model, these 'probably observable' regions always lie within the range 8 x 10{sup 4} GeV≤m{sub σ}≤2 x 10{sup 7} GeV, where m{sub σ} is the curvaton mass, and the Hubble scale at horizon exit is chosen as H{sub *}=10{sup 10} GeV. Because the 'probably observable' region depends on the total duration of inflation, information on parameters in the Lagrangian from particle physics and from precision CMB observables can therefore provide information about the total duration of inflation, not just the last N{sub obs} e-folds. This method could also be applied to any model that contains additional scalar fields to determine the probability that these scalar fields contribute to the curvature perturbation.

  16. Forecasting the natural gas demand in China using a self-adapting intelligent grey model

    International Nuclear Information System (INIS)

    Zeng, Bo; Li, Chuan

    2016-01-01

    Reasonably forecasting demands of natural gas in China is of significance as it could aid Chinese government in formulating energy policies and adjusting industrial structures. To this end, a self-adapting intelligent grey prediction model is proposed in this paper. Compared with conventional grey models which have the inherent drawbacks of fixed structure and poor adaptability, the proposed new model can automatically optimize model parameters according to the real data characteristics of modeling sequence. In this study, the proposed new model, discrete grey model, even difference grey model and classical grey model were employed, respectively, to simulate China's natural gas demands during 2002–2010 and forecast demands during 2011–2014. The results show the new model has the best simulative and predictive precision. Finally, the new model is used to forecast China's natural gas demand during 2015–2020. The forecast shows the demand will grow rapidly over the next six years. Therefore, in order to maintain the balance between the supplies and the demands for the natural gas in the future, Chinese government needs to take some measures, such as importing huge amounts of natural gas from abroad, increasing the domestic yield, using more alternative energy, and reducing the industrial reliance on natural gas. - Highlights: • A self-adapting intelligent grey prediction model (SIGM) is proposed in this paper. • The SIGM has the advantage of working with exponential functions and linear functions. • The SIGM solves the drawbacks of fixed structure and poor adaptability of grey models. • The demand of natural gas in China is successfully forecasted using the SIGM model. • The study findings can help Chinese government reasonably formulate energy policies.

  17. A mathematical framework for modelling and evaluating natural gas pipeline networks under hydrogen injection

    Energy Technology Data Exchange (ETDEWEB)

    Tabkhi, F.; Azzaro-Pantel, C.; Pibouleau, L.; Domenech, S. [Laboratoire de Genie Chimique, UMR5503 CNRS/INP/UPS, 5 rue Paulin Talabot F-BP1301, 31106 Toulouse Cedex 1 (France)

    2008-11-15

    This article presents the framework of a mathematical formulation for modelling and evaluating natural gas pipeline networks under hydrogen injection. The model development is based on gas transport through pipelines and compressors which compensate for the pressure drops by implying mainly the mass and energy balances on the basic elements of the network. The model was initially implemented for natural gas transport and the principle of extension for hydrogen-natural gas mixtures is presented. The objective is the treatment of the classical fuel minimizing problem in compressor stations. The optimization procedure has been formulated by means of a nonlinear technique within the General Algebraic Modelling System (GAMS) environment. This work deals with the adaptation of the current transmission networks of natural gas to the transport of hydrogen-natural gas mixtures. More precisely, the quantitative amount of hydrogen that can be added to natural gas can be determined. The studied pipeline network, initially proposed in [1] is revisited here for the case of hydrogen-natural gas mixtures. Typical quantitative results are presented, showing that the addition of hydrogen to natural gas decreases significantly the transmitted power: the maximum fraction of hydrogen that can be added to natural gas is around 6 mass% for this example. (author)

  18. Modeling of Thermal Behavior of Raw Natural Gas Air Coolers

    Science.gov (United States)

    Scherbinin, S. V.; Prakhova, M. Yu; Krasnov, A. N.; Khoroshavina, E. A.

    2018-05-01

    When gas is being prepared for a long-range transportation, it passes through air cooling units (ACUs) after compressing; there, hot gas passing through finned tubes is cooled with air streams. ACU's mode of operation shall ensure a certain value of gas temperature at the ACU's outlet. At that, when cooling raw gas, temperature distribution along all the tubes shall be known to prevent local hydrate formation. The paper proposes a mathematical model allowing one to obtain a thermal field distribution inside the ACU and study influence of various factors onto it.

  19. Naturally light Dirac neutrino in Left-Right Symmetric Model

    Energy Technology Data Exchange (ETDEWEB)

    Borah, Debasish [Department of Physics, Indian Institute of Technology Guwahati, Assam-781039 (India); Dasgupta, Arnab, E-mail: dborah@iitg.ernet.in, E-mail: arnab.d@iopb.res.in [Institute of Physics, HBNI, Sachivalaya Marg, Bhubaneshwar-751005 (India)

    2017-06-01

    We study the possibility of generating tiny Dirac masses of neutrinos in Left-Right Symmetric Model (LRSM) without requiring the existence of any additional symmetries. The charged fermions acquire masses through a universal seesaw mechanism due to the presence of additional vector like fermions. The neutrinos acquire a one-loop Dirac mass from the same additional vector like charged leptons without requiring any additional discrete symmetries. The model can also be extended by an additional Z {sub 2} symmetry in order to have a scotogenic version of this scenario predicting a stable dark matter candidate. We show that the latest Planck upper bound on the effective number of relativistic degrees of freedom N {sub eff}=3.15 ± 0.23 tightly constrains the right sector gauge boson masses to be heavier than 3.548 TeV . This bound on gauge boson mass also affects the allowed values of right scalar doublet dark matter mass from the requirement of satisfying the Planck bound on dark matter relic abundance. We also discuss the possible implications of such a scenario in charged lepton flavour violation and generating observable electric dipole moment of leptons.

  20. Nature preservation acceptance model applied to tanker oil spill simulations

    DEFF Research Database (Denmark)

    Friis-Hansen, Peter; Ditlevsen, Ove Dalager

    2003-01-01

    is exemplified by a study of oil spills due to simulated tanker collisions in the Danish straits. It is found that the distribution of the oil spill volume per spill is well represented by an exponential distribution both in Oeresund and in Great Belt. When applied in the Poisson model, a risk profile reasonably...... acceptance criterion for the pollution of the environment. This NPWI acceptance criterion is applied to the oil spill example....... be defined in a similar way as the so-called Life Quality Index defined by Nathwani et al [Nathwani JS, Lind NC, Padey MD. Affordable safety by choice: the life quality method. Institute for Risk Research, University of Waterloo; Waterloo (Ontario, Canada):1997], and can be used to quantify the risk...

  1. Lattice Boltzmann model for melting with natural convection

    International Nuclear Information System (INIS)

    Huber, Christian; Parmigiani, Andrea; Chopard, Bastien; Manga, Michael; Bachmann, Olivier

    2008-01-01

    We develop a lattice Boltzmann method to couple thermal convection and pure-substance melting. The transition from conduction-dominated heat transfer to fully-developed convection is analyzed and scaling laws and previous numerical results are reproduced by our numerical method. We also investigate the limit in which thermal inertia (high Stefan number) cannot be neglected. We use our results to extend the scaling relations obtained at low Stefan number and establish the correlation between the melting front propagation and the Stefan number for fully-developed convection. We conclude by showing that the model presented here is particularly well-suited to study convection melting in geometrically complex media with many applications in geosciences

  2. Turbulence model for melt pool natural convection heat transfer

    International Nuclear Information System (INIS)

    Kelkar, K.M.; Patankar, S.V.

    1994-01-01

    Under severe reactor accident scenarios, pools of molten core material may form in the reactor core or in the hemispherically shaped lower plenum of the reactor vessel. Such molten pools are internally heated due to the radioactive decay heat that gives rise to buoyant flows in the molten pool. The flow in such pools is strongly influenced by the turbulent mixing because the expected Rayleigh numbers under accidents scenarios are very high. The variation of the local heat flux over the boundaries of the molten pools are important in determining the subsequent melt progression behavior. This study reports results of an ongoing effort towards providing a well validated mathematical model for the prediction of buoyant flow and heat transfer in internally heated pool under conditions expected in severe accident scenarios

  3. An optimization model for natural gas supply portfolios of a power generation company

    International Nuclear Information System (INIS)

    Jirutitijaroen, Panida; Kim, Sujin; Kittithreerapronchai, Oran; Prina, José

    2013-01-01

    Highlights: ► An optimization model for daily operation of a natural gas-fired generation company is proposed. ► The model considers uncertainties in electricity price and natural gas price. ► The model is formulated to capture the hedging decisions by the company. ► The solution yields quantities of natural gas, generating schedule and purchasing quantities of electricity. ► Higher profit can be achieved by adapting inventory and production to the actual spot prices of natural gas and electricity. - Abstract: This paper considers a deregulated electricity market environment where a natural gas-fired generation company can engage in different types of contracts to manage its natural gas supply as well as trade on the electricity market. If the contracts are properly designed, they can protect the company from fluctuations in electricity price and demand, at some cost to the company’s expected profit. This reduction in profit can be mitigated by trading on the natural gas and electricity spot markets, but this trading activity may also sometimes result in losses. A stochastic programming model is formulated to capture the hedging decisions made by the company, as well as the interactions between the natural gas and electricity markets. The benefits offered by this approach for profit maximization in a variety of business scenarios, such as the case where the company can hold some amount of gas in storage are studied and presented. It is found that the stochastic model enables the company to optimize the electricity generation schedule and the natural gas consumption, including spot price transactions and gas storage management. Several managerial insights into the natural gas market, natural gas storage, and distribution profit are given

  4. Monitoring strategies and scale appropriate hydrologic and biogeochemical modelling for natural resource management

    DEFF Research Database (Denmark)

    Bende-Michl, Ulrike; Volk, Martin; Harmel, Daren

    2011-01-01

    This short communication paper presents recommendations for developing scale-appropriate monitoring and modelling strategies to assist decision making in natural resource management (NRM). These ideas presented here were discussed in the session (S5) ‘Monitoring strategies and scale...... and communication between researcher and model developer on the one side, and natural resource managers and the model users on the other side to increase knowledge in: 1) the limitations and uncertainties of current monitoring and modelling strategies, 2) scale-dependent linkages between monitoring and modelling...

  5. MODELLING OF THIN LAYER DRYING KINETICS OF COCOA BEANS DURING ARTIFICIAL AND NATURAL DRYING

    Directory of Open Access Journals (Sweden)

    C.L. HII

    2008-04-01

    Full Text Available Drying experiments were conducted using air-ventilated oven and sun dryer to simulate the artificial and natural drying processes of cocoa beans. The drying data were fitted with several published thin layer drying models. A new model was introduced which is a combination of the Page and two-term drying model. Selection of the best model was investigated by comparing the determination of coefficient (R2, reduced chi-square (2 and root mean square error (RMSE between the experimental and predicted values. The results showed that the new model was found best described the artificial and natural drying kinetics of cocoa under the conditions tested.

  6. Naturalism and the social model of disability: allied or antithetical?

    Science.gov (United States)

    Sisti, Dominic A

    2015-07-01

    The question of how disability should be defined is fraught with political, ethical and philosophical complexities. The social model of disability, which posits that disability is socially and politically constructed and is characterised by systemic barriers, has enjoyed broad acceptance that is exemplified by the slow but steady progress in securing civil rights for persons with disabilities. Yet, there remains a palpable tension between disability studies scholars and activists and bioethicists. While philosophers and bioethicists should heed the theories developed from the standpoint of persons with disabilities, disability activists should acknowledge the possibility that philosophical theories about the basic reality of disease, illness, health, function and impairment offer a more steady foundation for social or political critiques of disability. I argue that naturalistic theories of function and dysfunction provide a valuable starting point to clarify questions about the broader concept of disability. A naturalist theory of function may serve as the core of the concept of disability and provide disability scholars and bioethicists alike a stronger set of arguments in analysing real or potential instances of disability. 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.

  7. Standard model for safety analysis report of hexafluoride power plants from natural uranium

    International Nuclear Information System (INIS)

    1983-01-01

    The standard model for safety analysis report for hexafluoride production power plants from natural uranium is presented, showing the presentation form, the nature and the degree of detail, of the minimal information required by the Brazilian Nuclear Energy Commission - CNEN. (E.G.) [pt

  8. A computational fluid dynamics model for designing heat exchangers based on natural convection

    NARCIS (Netherlands)

    Dirkse, M.H.; Loon, van W.K.P.; Walle, van der T.; Speetjens, S.L.; Bot, G.P.A.

    2006-01-01

    A computational fluid dynamics model was created for the design of a natural convection shell-and-tube heat exchanger with baffles. The flow regime proved to be turbulent and this was modelled using the k¿¿ turbulence model. The features of the complex geometry were simplified considerably resulting

  9. Statistical Language Models and Information Retrieval: Natural Language Processing Really Meets Retrieval

    NARCIS (Netherlands)

    Hiemstra, Djoerd; de Jong, Franciska M.G.

    2001-01-01

    Traditionally, natural language processing techniques for information retrieval have always been studied outside the framework of formal models of information retrieval. In this article, we introduce a new formal model of information retrieval based on the application of statistical language models.

  10. Chemical speciation modelling of the South Terras and Madeira Abyssal Plain natural analogue sites

    International Nuclear Information System (INIS)

    Duffield, J.R.; Xu Langqui; Williams, D.R.

    1988-11-01

    The chemical speciation of uranium has been modelled using field data from the South Terras and Madeira Abyssal Plain natural analogue sites. In general, validation is good, particularly for the Abyssal Plain model. Problems regarding uranium redox couples have been highlighted as have other areas requiring further consideration for building into the thermodynamic models. (author)

  11. The Communication Model and the Nature of Change in Terms of Deforestation in China since 1949

    Science.gov (United States)

    Tian, Dexin; Chao, Chin-Chung

    2010-01-01

    This article explores the communication model and nature of change in terms of deforestation in China since 1949. Through Lasswell's communication model and the theory of change and via historical analysis and extended literature review, we have discovered: First, Mao's government adopted an effective one-way top-down communication model with…

  12. An integrated transient model for simulating the operation of natural gas transport systems

    NARCIS (Netherlands)

    Pambour, Kwabena Addo; Bolado-Lavin, Ricardo; Dijkema, Gerard P. J.

    This paper presents an integrated transient hydraulic model that describes the dynamic behavior of natural gas transport systems (GTS). The model includes sub models of the most important facilities comprising a GTS, such as pipelines, compressor stations, pressure reduction stations, underground

  13. Adaptive institutions? Peasant institutions and natural models facing climatic and economic changes in the Colombian Andes

    NARCIS (Netherlands)

    Feola, Giuseppe

    2017-01-01

    In the Colombian Andes, peasants have co-evolved with their environment for centuries, but it is uncertain whether traditional informal institutions and natural models are adapting to current and possibly unprecedented economic and climatic disturbances. This study investigated institutional

  14. A new model for the accurate calculation of natural gas viscosity

    OpenAIRE

    Xiaohong Yang; Shunxi Zhang; Weiling Zhu

    2017-01-01

    Viscosity of natural gas is a basic and important parameter, of theoretical and practical significance in the domain of natural gas recovery, transmission and processing. In order to obtain the accurate viscosity data efficiently at a low cost, a new model and its corresponding functional relation are derived on the basis of the relationship among viscosity, temperature and density derived from the kinetic theory of gases. After the model parameters were optimized using a lot of experimental ...

  15. Occurrence of the structural enterocin A, P, B, L50B genes in enterococci of different origin.

    Science.gov (United States)

    Strompfová, Viola; Lauková, Andrea; Simonová, Monika; Marcináková, Miroslava

    2008-12-10

    Enterococci are well-known producers of antimicrobial peptides--bacteriocins (enterocins) and the number of characterized enterocins has been significantly increased. Recently, enterocins are of great interest for their potential as biopreservatives in food or feed while research on enterocins as alternative antimicrobials in humans and animals is only at the beginning. The present study provides a survey about the occurrence of enterocin structural genes A, P, B, L50B in a target of 427 strains of Enterococcus faecium (368) and Enterococcus faecalis (59) species from different sources (animal isolates, food and feed) performed by PCR method. Based on our results, 234 strains possessed one or more enterocin structural gene(s). The genes of enterocin P and enterocin A were the most frequently detected structural genes among the PCR positive strains (170 and 155 strains, respectively). Different frequency of the enterocin genes occurrence was detected in strains according to their origin; the strains from horses and silage showed the highest frequency of enterocin genes presence. All possible combinations of the tested genes occurred at least twice except the combination of the gene of enterocin B and L50B which possessed neither strain. The gene of enterocin A was exclusively detected among E. faecium strains, while the gene of enterocin P, B, L50B were detected in strains of both species E. faecium and E. faecalis. In conclusion, a high-frequency and variability of enterocin structural genes exists among enterococci of different origin what offers a big possibility to find effective bacteriocin-producing strains for their application in veterinary medicine.

  16. NATBWR: a steady-state model for natural circulation in boiling-water reactors

    International Nuclear Information System (INIS)

    Healzer, J.M.; Abdollahian, D.

    1983-02-01

    This report documents the NATBWR steady-state BWR natural-circulation model and activities under EPRI Project RP1561-1 to gather data and predict the natural-circulation operation of the BWR. The report is organized into two parts, with the first part describing the NATBWR model and applications of the model to available BWR natural-circulation data and the second part providing user and programming information about the model. Five different operating BWR's were selected to demonstrate the application of the NATBWR model, one of each type from BWR/1 through BWR/4. For each operating plant, the available natural circulation data has been compared to model predictions. In addition to the data predictions, the behavior of the BWR system at reduced inventory, where the system is isolated and scrammed, and cooling provided by natural circulation has been analyzed. Finally, included as an appendix to Part 1 of this report is a discussion of the stability of the BWR system at natural-circulation conditions

  17. Integrating human and natural systems in community psychology: an ecological model of stewardship behavior.

    Science.gov (United States)

    Moskell, Christine; Allred, Shorna Broussard

    2013-03-01

    Community psychology (CP) research on the natural environment lacks a theoretical framework for analyzing the complex relationship between human systems and the natural world. We introduce other academic fields concerned with the interactions between humans and the natural environment, including environmental sociology and coupled human and natural systems. To demonstrate how the natural environment can be included within CP's ecological framework, we propose an ecological model of urban forest stewardship action. Although ecological models of behavior in CP have previously modeled health behaviors, we argue that these frameworks are also applicable to actions that positively influence the natural environment. We chose the environmental action of urban forest stewardship because cities across the United States are planting millions of trees and increased citizen participation in urban tree planting and stewardship will be needed to sustain the benefits provided by urban trees. We used the framework of an ecological model of behavior to illustrate multiple levels of factors that may promote or hinder involvement in urban forest stewardship actions. The implications of our model for the development of multi-level ecological interventions to foster stewardship actions are discussed, as well as directions for future research to further test and refine the model.

  18. Mathematical and computational modeling with applications in natural and social sciences, engineering, and the arts

    CERN Document Server

    Melnik, Roderick

    2015-01-01

    Illustrates the application of mathematical and computational modeling in a variety of disciplines With an emphasis on the interdisciplinary nature of mathematical and computational modeling, Mathematical and Computational Modeling: With Applications in the Natural and Social Sciences, Engineering, and the Arts features chapters written by well-known, international experts in these fields and presents readers with a host of state-of-the-art achievements in the development of mathematical modeling and computational experiment methodology. The book is a valuable guide to the methods, ideas,

  19. Activity measurement and effective dose modelling of natural radionuclides in building material.

    Science.gov (United States)

    Maringer, F J; Baumgartner, A; Rechberger, F; Seidel, C; Stietka, M

    2013-11-01

    In this paper the assessment of natural radionuclides' activity concentration in building materials, calibration requirements and related indoor exposure dose models is presented. Particular attention is turned to specific improvements in low-level gamma-ray spectrometry to determine the activity concentration of necessary natural radionuclides in building materials with adequate measurement uncertainties. Different approaches for the modelling of the effective dose indoor due to external radiation resulted from natural radionuclides in building material and results of actual building material assessments are shown. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Modeling the transient security constraints of natural gas network in day-ahead power system scheduling

    DEFF Research Database (Denmark)

    Yang, Jingwei; Zhang, Ning; Kang, Chongqing

    2017-01-01

    The rapid deployment of gas-fired generating units makes the power system more vulnerable to failures in the natural gas system. To reduce the risk of gas system failure and to guarantee the security of power system operation, it is necessary to take the security constraints of natural gas...... accurately, they are hard to be embedded into the power system scheduling model, which consists of algebraic equations and inequations. This paper addresses this dilemma by proposing an algebraic transient model of natural gas network which is similar to the branch-node model of power network. Based...... pipelines into account in the day-ahead power generation scheduling model. However, the minute- and hour-level dynamic characteristics of gas systems prevents an accurate decision-making simply with the steady-state gas flow model. Although the partial differential equations depict the dynamics of gas flow...

  1. Direct numerical simulation and modeling of turbulent natural convection in a vertical differentially heated slot

    International Nuclear Information System (INIS)

    Boudjemadi, R.

    1996-03-01

    The main objectives of this thesis are the direct numerical simulation of natural convection in a vertical differentially heated slot and the improvements of second-order turbulence modelling. A three-dimensional direct numerical simulation code has been developed in order to gain a better understanding of turbulence properties in natural convection flows. This code has been validated in several physical configurations: non-stratified natural convection flows (conduction solution), stratified natural convection flows (double boundary layer solution), transitional and turbulent Poiseuille flows. For the conduction solution, the turbulent regime was reached at a Rayleigh number of 1*10 5 and 5.4*10 5 . A detailed analysis of these results has revealed the principal qualities of the available models but has also pointed our their shortcomings. This data base has been used in order to improve the triple correlations transport models and to select the turbulent time scales suitable for such flows. (author). 122 refs., figs., tabs., 4 appends

  2. Dynamic model updating based on strain mode shape and natural frequency using hybrid pattern search technique

    Science.gov (United States)

    Guo, Ning; Yang, Zhichun; Wang, Le; Ouyang, Yan; Zhang, Xinping

    2018-05-01

    Aiming at providing a precise dynamic structural finite element (FE) model for dynamic strength evaluation in addition to dynamic analysis. A dynamic FE model updating method is presented to correct the uncertain parameters of the FE model of a structure using strain mode shapes and natural frequencies. The strain mode shape, which is sensitive to local changes in structure, is used instead of the displacement mode for enhancing model updating. The coordinate strain modal assurance criterion is developed to evaluate the correlation level at each coordinate over the experimental and the analytical strain mode shapes. Moreover, the natural frequencies which provide the global information of the structure are used to guarantee the accuracy of modal properties of the global model. Then, the weighted summation of the natural frequency residual and the coordinate strain modal assurance criterion residual is used as the objective function in the proposed dynamic FE model updating procedure. The hybrid genetic/pattern-search optimization algorithm is adopted to perform the dynamic FE model updating procedure. Numerical simulation and model updating experiment for a clamped-clamped beam are performed to validate the feasibility and effectiveness of the present method. The results show that the proposed method can be used to update the uncertain parameters with good robustness. And the updated dynamic FE model of the beam structure, which can correctly predict both the natural frequencies and the local dynamic strains, is reliable for the following dynamic analysis and dynamic strength evaluation.

  3. Modelling techniques for predicting the long term consequences of radiation on natural aquatic populations

    International Nuclear Information System (INIS)

    Wallis, I.G.

    1978-01-01

    The purpose of this working paper is to describe modelling techniques for predicting the long term consequences of radiation on natural aquatic populations. Ideally, it would be possible to use aquatic population models: (1) to predict changes in the health and well-being of all aquatic populations as a result of changing the composition, amount and location of radionuclide discharges; (2) to compare the effects of steady, fluctuating and accidental releases of radionuclides; and (3) to evaluate the combined impact of the discharge of radionuclides and other wastes, and natural environmental stresses on aquatic populations. At the onset it should be stated that there is no existing model which can achieve this ideal performance. However, modelling skills and techniques are available to develop useful aquatic population models. This paper discusses the considerations involved in developing these models and briefly describes the various types of population models which have been developed to date

  4. Model of natural ventilation by using a coupled thermal-airflow simulation program

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg; Remmen, Arne

    2012-01-01

    This article presents a model of natural ventilation of buildings at the stage of design and a consequence of the behaviour of the occupants. An evaluation is made by coupling multizone air modelling and thermal building simulation using a deterministic set of input factors comprising among others...

  5. Harvesting cost model for small trees in natural stands in the interior northwest.

    Science.gov (United States)

    Bruce R. Hartsough; Xiaoshan Zhang; Roger D. Fight

    2001-01-01

    Realistic logging cost models are needed for long-term forest management planning. Data from numerous published studies were combined to estimate the costs of harvesting small trees in natural stands in the Interior Northwest of North America. Six harvesting systems were modeled. Four address gentle terrain: manual log-length, manual whole-tree, mechanized whole-tree,...

  6. Derivation and Implementation of a Model Teaching the Nature of Science Using Informal Science Education Venues

    Science.gov (United States)

    Spector, Barbara S.; Burkett, Ruth; Leard, Cyndy

    2012-01-01

    This paper introduces a model for using informal science education venues as contexts within which to teach the nature of science. The model was initially developed to enable university education students to teach science in elementary schools so as to be consistent with "National Science Education Standards" (NSES) (1996) and "A Framework for…

  7. A simple technique for obtaining future climate data inputs for natural resource models

    Science.gov (United States)

    Those conducting impact studies using natural resource models need to be able to quickly and easily obtain downscaled future climate data from multiple models, scenarios, and timescales for multiple locations. This paper describes a method of quickly obtaining future climate data over a wide range o...

  8. Modelling the phonotactic structure of natural language words with simple recurrent networks

    NARCIS (Netherlands)

    Stoianov, [No Value; Nerbonne, J; Bouma, H; Coppen, PA; vanHalteren, H; Teunissen, L

    1998-01-01

    Simple Recurrent Networks (SRN) are Neural Network (connectionist) models able to process natural language. Phonotactics concerns the order of symbols in words. We continued an earlier unsuccessful trial to model the phonotactics of Dutch words with SRNs. In order to overcome the previously reported

  9. BSim models for 2 case-studies of naturally and mechanically ventilated daycare institutions

    Energy Technology Data Exchange (ETDEWEB)

    Kalyanova, O.; Heiselberg, P.

    2009-06-15

    The report intends to provide complete information necessary for evaluation of assumptions made in the models and conclusions derived from the results of simulation of two different institutions in various operational modes. Thermal models are prepared for two day-care buildings, one which is mechanically ventilated and one which is naturally ventilated. All simulations were preformed in BSim, and all the models are simulated in the current version og BSim which is version 6,8,9,8. The results of the simulations showed that it is possible to reduce energy use for ventilation, both in mechanically and naturally ventilated child care center without compromising indoor air quality. (ln)

  10. A Dynamic Model of the Combined Electricity and Natural Gas Markets

    DEFF Research Database (Denmark)

    Jenkins, Sandra; Annaswamy, Anuradha M.; Hansen, Jacob

    2015-01-01

    With the shale gas revolution, coal retirements, environmental regulations, and increasing renewable energy resources, the interdependency of natural gas and electricity has grown significantly. Interdependency challenges, such as mismatched market schedules and disparate market operations, require...... quantitative modeling in order to garner insights into the effectiveness of various solutions. In this paper, a quantitative model with a dynamic market mechanism is proposed to evaluate the effects of the fuel uncertainty of natural gas-fired power plants on Social Welfare. The results of the model show...

  11. A predictive model of natural gas mixture combustion in internal combustion engines

    Directory of Open Access Journals (Sweden)

    Henry Espinoza

    2007-05-01

    Full Text Available This study shows the development of a predictive natural gas mixture combustion model for conventional com-bustion (ignition engines. The model was based on resolving two areas; one having unburned combustion mixture and another having combustion products. Energy and matter conservation equations were solved for each crankshaft turn angle for each area. Nonlinear differential equations for each phase’s energy (considering compression, combustion and expansion were solved by applying the fourth-order Runge-Kutta method. The model also enabled studying different natural gas components’ composition and evaluating combustion in the presence of dry and humid air. Validation results are shown with experimental data, demonstrating the software’s precision and accuracy in the results so produced. The results showed cylinder pressure, unburned and burned mixture temperature, burned mass fraction and combustion reaction heat for the engine being modelled using a natural gas mixture.

  12. Geo-inspired model: Agents vectors naturals inspired by the environmental management (AVNG of water tributaries

    Directory of Open Access Journals (Sweden)

    Edwin Eduardo Millán Rojas

    2018-02-01

    Full Text Available Context: Management to care for the environment and the Earth (geo can be source of inspiration for developing models that allow addressing complexity issues; the objective of this research was to develop an additional aspect of the inspired models. The geoinspired model has two features, the first covering aspects related to environmental management and the behavior of natural resources, and the second has a component of spatial location associated with existing objects on the Earth's surface. Method: The approach developed in the research is descriptive and its main objective is the representation or characterization of a case study within a particular context. Results: The result was the design of a model to emulate the natural behavior of the water tributaries of the Amazon foothills, in order to extend the application of the inspired models and allow the use of elements such as geo-referencing and environmental management. The proposed geoinspired model is called “natural vectors agents inspired in environmental management”. Conclusions: The agents vectors naturals inspired by the environmental are polyform elements that can assume the behavior of environmental entities, which makes it possible to achieve progress in other fields of environmental management (use of soil, climate, flora, fauna, and link environmental issues with the structure of the proposed model.

  13. Development and verification of a space-dependent dynamic model of a natural circulation steam generator

    International Nuclear Information System (INIS)

    Mewdell, C.G.; Harrison, W.C.; Hawley, E.H.

    1980-01-01

    This paper describes the development and verification of a Non-Linear Space-Dependent Dynamic Model of a Natural Circulation Steam Generator typical of boilers used in CANDU nuclear power stations. The model contains a detailed one-dimensional dynamic description of both the primary and secondary sides of an integral pre-heater natural circulation boiler. Two-phase flow effects on the primary side are included. The secondary side uses a drift-flux model in the boiling sections and a detailed non-equilibrium point model for the steam drum. The paper presents the essential features of the final model called BOILER-2, its solution scheme, the RD-12 loop and test boiler, the boiler steady-state and transient experiments, and the comparison of the model predictions with experimental results. (author)

  14. Sustaining Economic Exploitation of Complex Ecosystems in Computational Models of Coupled Human-Natural Networks

    OpenAIRE

    Martinez, Neo D.; Tonin, Perrine; Bauer, Barbara; Rael, Rosalyn C.; Singh, Rahul; Yoon, Sangyuk; Yoon, Ilmi; Dunne, Jennifer A.

    2012-01-01

    Understanding ecological complexity has stymied scientists for decades. Recent elucidation of the famously coined "devious strategies for stability in enduring natural systems" has opened up a new field of computational analyses of complex ecological networks where the nonlinear dynamics of many interacting species can be more realistically mod-eled and understood. Here, we describe the first extension of this field to include coupled human-natural systems. This extension elucidates new strat...

  15. Laser anemometry measurements of natural circulation flow in a scale model PWR system

    International Nuclear Information System (INIS)

    Kadambi, J.R.; Schneider, S.J.

    1990-01-01

    This paper reports on experimental studies conducted to investigate the natural circulation of a single-phase fluid in a scale model pressurized water reactor system during a postulated degraded core accident. A half-section of a 1/7 scale model with a plexiglass adiabatic window was used. Water and sulfurhexafluoride (SF 6 ) were used as the fluid. Laser-Doppler anemometry (LDA) was used in marking the velocity measurements along the center plane of the model at five elevations

  16. Modeling the evolution of natural cliffs subject to weathering. 1, Limit analysis approach

    OpenAIRE

    Utili, Stefano; Crosta, Giovanni B.

    2011-01-01

    Retrogressive landsliding evolution of natural slopes subjected to weathering has been modeled by assuming Mohr-Coulomb material behavior and by using an analytical method. The case of weathering-limited slope conditions, with complete erosion of the accumulated debris, has been modeled. The limit analysis upper-bound method is used to study slope instability induced by a homogeneous decrease of material strength in space and time. The only assumption required in the model concerns the degree...

  17. Optimizing the structure of the natural gas market using an agent-based modeling framework

    Energy Technology Data Exchange (ETDEWEB)

    Van Benthem, M.

    2010-01-14

    The overall research question guiding this study is as follows: what is the optimal structure of the natural gas market, considering both the degrees of affordability and supply security resulting from this structure? The sub-questions are: How can the concepts of supply security and affordability be usefully defined? (Chapter 2); What should a modeling framework for analyzing the natural gas market with regard to these concepts look like? (Chapters 3 and 4); What general conclusions can be drawn on the basis of this framework? (Chapter 5); What is the effect of liberalization on the Dutch natural gas market? (Chapter 6); What are the possible effects of current trends unfolding in the Dutch natural gas market? (Chapter 7). The framework constructed in this study implicitly contains the necessary elements for deriving a sustainability indicator too. However, to limit the scope of the study, sustainability will not be analyzed explicitly. Chapter 2 provides an introductory description of the natural gas market. Starting from a description of the natural gas value chain, the process of liberalization is described as a change in the organization of the value chain. In addition, the concepts of affordability and supply security are discussed and appropriate quantitative indicators for both objectives are identified. In Chapter 3, a survey of existing gas market models is performed. On the basis of this survey, a classification system for natural gas market models is developed. Furthermore, the characteristics of a modeling framework fit for the purpose of this study are derived. In Chapter 4, a general, quantitative framework for natural gas market modeling is developed on the basis of agent-based computational economics. The model's structure, its dynamics, output and data requirements are described. Furthermore, the properties of each agent are explored, and the possibilities for model verification and validation are outlined. Chapter 5 provides a number of

  18. Optimizing the structure of the natural gas market using an agent-based modeling framework

    International Nuclear Information System (INIS)

    Van Benthem, M.

    2010-01-01

    The overall research question guiding this study is as follows: what is the optimal structure of the natural gas market, considering both the degrees of affordability and supply security resulting from this structure? The sub-questions are: How can the concepts of supply security and affordability be usefully defined? (Chapter 2); What should a modeling framework for analyzing the natural gas market with regard to these concepts look like? (Chapters 3 and 4); What general conclusions can be drawn on the basis of this framework? (Chapter 5); What is the effect of liberalization on the Dutch natural gas market? (Chapter 6); What are the possible effects of current trends unfolding in the Dutch natural gas market? (Chapter 7). The framework constructed in this study implicitly contains the necessary elements for deriving a sustainability indicator too. However, to limit the scope of the study, sustainability will not be analyzed explicitly. Chapter 2 provides an introductory description of the natural gas market. Starting from a description of the natural gas value chain, the process of liberalization is described as a change in the organization of the value chain. In addition, the concepts of affordability and supply security are discussed and appropriate quantitative indicators for both objectives are identified. In Chapter 3, a survey of existing gas market models is performed. On the basis of this survey, a classification system for natural gas market models is developed. Furthermore, the characteristics of a modeling framework fit for the purpose of this study are derived. In Chapter 4, a general, quantitative framework for natural gas market modeling is developed on the basis of agent-based computational economics. The model's structure, its dynamics, output and data requirements are described. Furthermore, the properties of each agent are explored, and the possibilities for model verification and validation are outlined. Chapter 5 provides a number of

  19. Industrial natural gas consumption in the United States: an empirical model for evaluating future trends

    International Nuclear Information System (INIS)

    Huntington, H.G.

    2007-01-01

    This study develops a statistical model of industrial US natural gas consumption based upon historical data for the 1958-2003 period. The model specifically addresses interfuel substitution possibilities and changes in the industrial economic base. Using a relatively simple approach, the framework can be simulated repeatedly with little effort over a range of different conditions. It may also provide a valuable input into larger modeling exercises where an organization wants to determine long-run natural gas prices based upon supply and demand conditions. Projections based upon this demand framework indicate that industrial natural gas consumption may grow more slowly over the next 20 yr than being projected by the U.S. Energy Information Administration (EIA). This conclusion is based upon the assumption that natural gas prices will follow oil prices, as they have done over recent decades. If natural gas prices should lag well below oil prices, as envisioned by the latest EIA outlook, industrial natural gas consumption should rapidly expand well beyond the levels being projected by EIA. (author)

  20. Comparative analysis of modified PMV models and SET models to predict human thermal sensation in naturally ventilated buildings

    DEFF Research Database (Denmark)

    Gao, Jie; Wang, Yi; Wargocki, Pawel

    2015-01-01

    In this paper, a comparative analysis was performed on the human thermal sensation estimated by modified predicted mean vote (PMV) models and modified standard effective temperature (SET) models in naturally ventilated buildings; the data were collected in field study. These prediction models were....../s, the expectancy factors for the extended PMV model and the extended SET model were from 0.770 to 0.974 and from 1.330 to 1.363, and the adaptive coefficients for the adaptive PMV model and the adaptive SET model were from 0.029 to 0.167 and from-0.213 to-0.195. In addition, the difference in thermal sensation...... between the measured and predicted values using the modified PMV models exceeded 25%, while the difference between the measured thermal sensation and the predicted thermal sensation using modified SET models was approximately less than 25%. It is concluded that the modified SET models can predict human...

  1. Models development for natural circulation and its transition process in nuclear power plant

    International Nuclear Information System (INIS)

    Yu Lei; Cai Qi; Cai Zhangsheng; Xie Haiyan

    2008-01-01

    On the basis of nuclear power plant (NPP) best-estimate transient analysis code RELAP5/MOD3, the point reactor kinetics model in RELAP5/MOD3 was replaced by the two-group, 3-D space and time dependent neutron kinetic model, in order to exactly analyze the responses of key parameters in natural circulation and its transition process considering the reactivity feedback. The coupled model for three-dimensional physics and thermohydraulics was established and corresponding computing code was developed. Using developed code, natural circulation of NPP and its transiton process were calculated and analyzed. Compared with the experiment data, the calculated results show that its high precise avoids the shortage that the point reactor equation can not reflect the reactivity exactly. This code can be a computing and analysis tool for forced circulation and natural circulation and their transitions. (authors)

  2. Predicting the natural flow regime: Models for assessing hydrological alteration in streams

    Science.gov (United States)

    Carlisle, D.M.; Falcone, J.; Wolock, D.M.; Meador, M.R.; Norris, R.H.

    2009-01-01

    Understanding the extent to which natural streamflow characteristics have been altered is an important consideration for ecological assessments of streams. Assessing hydrologic condition requires that we quantify the attributes of the flow regime that would be expected in the absence of anthropogenic modifications. The objective of this study was to evaluate whether selected streamflow characteristics could be predicted at regional and national scales using geospatial data. Long-term, gaged river basins distributed throughout the contiguous US that had streamflow characteristics representing least disturbed or near pristine conditions were identified. Thirteen metrics of the magnitude, frequency, duration, timing and rate of change of streamflow were calculated using a 20-50 year period of record for each site. We used random forests (RF), a robust statistical modelling approach, to develop models that predicted the value for each streamflow metric using natural watershed characteristics. We compared the performance (i.e. bias and precision) of national- and regional-scale predictive models to that of models based on landscape classifications, including major river basins, ecoregions and hydrologic landscape regions (HLR). For all hydrologic metrics, landscape stratification models produced estimates that were less biased and more precise than a null model that accounted for no natural variability. Predictive models at the national and regional scale performed equally well, and substantially improved predictions of all hydrologic metrics relative to landscape stratification models. Prediction error rates ranged from 15 to 40%, but were 25% for most metrics. We selected three gaged, non-reference sites to illustrate how predictive models could be used to assess hydrologic condition. These examples show how the models accurately estimate predisturbance conditions and are sensitive to changes in streamflow variability associated with long-term land-use change. We also

  3. Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model.

    Science.gov (United States)

    Tang, Jiechen; Zhou, Chao; Yuan, Xinyu; Sriboonchitta, Songsak

    2015-01-01

    This paper concentrates on estimating the risk of Title Transfer Facility (TTF) Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT) is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR) and conditional value at risk (CVaR). Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

  4. Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model

    Directory of Open Access Journals (Sweden)

    Jiechen Tang

    2015-01-01

    Full Text Available This paper concentrates on estimating the risk of Title Transfer Facility (TTF Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR and conditional value at risk (CVaR. Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

  5. Pollutant Dispersion Modeling in Natural Streams Using the Transmission Line Matrix Method

    Directory of Open Access Journals (Sweden)

    Safia Meddah

    2015-09-01

    Full Text Available Numerical modeling has become an indispensable tool for solving various physical problems. In this context, we present a model of pollutant dispersion in natural streams for the far field case where dispersion is considered longitudinal and one-dimensional in the flow direction. The Transmission Line Matrix (TLM, which has earned a reputation as powerful and efficient numerical method, is used. The presented one-dimensional TLM model requires a minimum input data and provides a significant gain in computing time. To validate our model, the results are compared with observations and experimental data from the river Severn (UK. The results show a good agreement with experimental data. The model can be used to predict the spatiotemporal evolution of a pollutant in natural streams for effective and rapid decision-making in a case of emergency, such as accidental discharges in a stream with a dynamic similar to that of the river Severn (UK.

  6. An ontology model for nursing narratives with natural language generation technology.

    Science.gov (United States)

    Min, Yul Ha; Park, Hyeoun-Ae; Jeon, Eunjoo; Lee, Joo Yun; Jo, Soo Jung

    2013-01-01

    The purpose of this study was to develop an ontology model to generate nursing narratives as natural as human language from the entity-attribute-value triplets of a detailed clinical model using natural language generation technology. The model was based on the types of information and documentation time of the information along the nursing process. The typesof information are data characterizing the patient status, inferences made by the nurse from the patient data, and nursing actions selected by the nurse to change the patient status. This information was linked to the nursing process based on the time of documentation. We describe a case study illustrating the application of this model in an acute-care setting. The proposed model provides a strategy for designing an electronic nursing record system.

  7. Modeling natural emissions in the Community Multiscale Air Quality (CMAQ) Model-I: building an emissions data base

    Science.gov (United States)

    Smith, S. N.; Mueller, S. F.

    2010-05-01

    A natural emissions inventory for the continental United States and surrounding territories is needed in order to use the US Environmental Protection Agency Community Multiscale Air Quality (CMAQ) Model for simulating natural air quality. The CMAQ air modeling system (including the Sparse Matrix Operator Kernel Emissions (SMOKE) emissions processing system) currently estimates non-methane volatile organic compound (NMVOC) emissions from biogenic sources, nitrogen oxide (NOx) emissions from soils, ammonia from animals, several types of particulate and reactive gas emissions from fires, as well as sea salt emissions. However, there are several emission categories that are not commonly treated by the standard CMAQ Model system. Most notable among these are nitrogen oxide emissions from lightning, reduced sulfur emissions from oceans, geothermal features and other continental sources, windblown dust particulate, and reactive chlorine gas emissions linked with sea salt chloride. A review of past emissions modeling work and existing global emissions data bases provides information and data necessary for preparing a more complete natural emissions data base for CMAQ applications. A model-ready natural emissions data base is developed to complement the anthropogenic emissions inventory used by the VISTAS Regional Planning Organization in its work analyzing regional haze based on the year 2002. This new data base covers a modeling domain that includes the continental United States plus large portions of Canada, Mexico and surrounding oceans. Comparing July 2002 source data reveals that natural emissions account for 16% of total gaseous sulfur (sulfur dioxide, dimethylsulfide and hydrogen sulfide), 44% of total NOx, 80% of reactive carbonaceous gases (NMVOCs and carbon monoxide), 28% of ammonia, 96% of total chlorine (hydrochloric acid, nitryl chloride and sea salt chloride), and 84% of fine particles (i.e., those smaller than 2.5 μm in size) released into the atmosphere

  8. Modeling natural emissions in the Community Multiscale Air Quality (CMAQ) model - Part 1: Building an emissions data base

    Science.gov (United States)

    Smith, S. N.; Mueller, S. F.

    2010-01-01

    A natural emissions inventory for the continental United States and surrounding territories is needed in order to use the US Environmental Protection Agency Community Multiscale Air Quality (CMAQ) Model for simulating natural air quality. The CMAQ air modeling system (including the Sparse Matrix Operator Kernel Emissions (SMOKE) emissions processing system) currently estimates volatile organic compound (VOC) emissions from biogenic sources, nitrogen oxide (NOx) emissions from soils, ammonia from animals, several types of particulate and reactive gas emissions from fires, as well as windblown dust and sea salt emissions. However, there are several emission categories that are not commonly treated by the standard CMAQ Model system. Most notable among these are nitrogen oxide emissions from lightning, reduced sulfur emissions from oceans, geothermal features and other continental sources, and reactive chlorine gas emissions linked with sea salt chloride. A review of past emissions modeling work and existing global emissions data bases provides information and data necessary for preparing a more complete natural emissions data base for CMAQ applications. A model-ready natural emissions data base is developed to complement the anthropogenic emissions inventory used by the VISTAS Regional Planning Organization in its work analyzing regional haze based on the year 2002. This new data base covers a modeling domain that includes the continental United States plus large portions of Canada, Mexico and surrounding oceans. Comparing July 2002 source data reveals that natural emissions account for 16% of total gaseous sulfur (sulfur dioxide, dimethylsulfide and hydrogen sulfide), 44% of total NOx, 80% of reactive carbonaceous gases (VOCs and carbon monoxide), 28% of ammonia, 96% of total chlorine (hydrochloric acid, nitryl chloride and sea salt chloride), and 84% of fine particles (i.e., those smaller than 2.5 μm in size) released into the atmosphere. The seasonality and

  9. Evaluation of reduced chemical kinetic mechanisms used for modeling mild combustion for natural gas

    Directory of Open Access Journals (Sweden)

    Hamdi Mohamed

    2009-01-01

    Full Text Available A numerical and parametric study was performed to evaluate the potential of reduced chemistry mechanisms to model natural gas chemistry including NOx chemistry under mild combustion mode. Two reduced mechanisms, 5-step and 9-step, were tested against the GRI-Mech3.0 by comparing key species, such as NOx, CO2 and CO, and gas temperature predictions in idealized reactors codes under mild combustion conditions. It is thus concluded that the 9-step mechanism appears to be a promising reduced mechanism that can be used in multi-dimensional codes for modeling mild combustion of natural gas.

  10. Natural circulation in water cooled nuclear power plants: Phenomena, models, and methodology for system reliability assessments

    International Nuclear Information System (INIS)

    2005-11-01

    In recent years it has been recognized that the application of passive safety systems (i.e. those whose operation takes advantage of natural forces such as convection and gravity), can contribute to simplification and potentially to improved economics of new nuclear power plant designs. Further, the IAEA Conference on The Safety of Nuclear Power: Strategy for the Future which was convened in 1991 noted that for new plants 'the use of passive safety features is a desirable method of achieving simplification and increasing the reliability of the performance of essential safety functions, and should be used wherever appropriate'. Considering the weak driving forces of passive systems based on natural circulation, careful design and analysis methods must be employed to assure that the systems perform their intended functions. To support the development of advanced water cooled reactor designs with passive systems, investigations of natural circulation are an ongoing activity in several IAEA Member States. Some new designs also utilize natural circulation as a means to remove core power during normal operation. In response to the motivating factors discussed above, and to foster international collaboration on the enabling technology of passive systems that utilize natural circulation, an IAEA Coordinated Research Project (CRP) on Natural Circulation Phenomena, Modelling and Reliability of Passive Systems that Utilize Natural Circulation was started in early 2004. Building on the shared expertise within the CRP, this publication presents extensive information on natural circulation phenomena, models, predictive tools and experiments that currently support design and analyses of natural circulation systems and highlights areas where additional research is needed. Therefore, this publication serves both to provide a description of the present state of knowledge on natural circulation in water cooled nuclear power plants and to guide the planning and conduct of the CRP in

  11. The World gas model. A multi-period mixed complementarity model for the global natural gas market

    International Nuclear Information System (INIS)

    Egging, Ruud; Holz, Franziska; Gabriel, Steven A.

    2010-01-01

    We provide the description, mathematical formulation and illustrative results of the World Gas Model, a multi-period complementarity model for the global natural gas market with explicit consideration of market power in the upstream market. Market players include producers, traders, pipeline and storage operators, LNG (liquefied natural gas) liquefiers and regasifiers as well as marketers. The model data set contains more than 80 countries and regions and covers 98% of world wide natural gas production and consumption. We also include a detailed representation of cross-border natural gas pipelines and constraints imposed by long-term contracts in the LNG market. The model is calibrated to match production and consumption projections from the PRIMES [EC. European energy and transport: trends to 2030-update 2007. Brussels: European Commission; 2008] and POLES models [EC. World energy technology outlook - 2050 (WETO-H2). Brussels: European Commission; 2006] up to 2030. The results of our numerical simulations illustrate how the supply shares of pipeline and LNG in various regions in the world develop very differently over time. LNG will continue to play a major role in the Asian market, also for new importers like China and India. Europe will expand its pipeline import capacities benefiting from its relative proximity to major gas suppliers. (author)

  12. Applying the Land Use Portfolio Model with Hazus to analyse risk from natural hazard events

    Science.gov (United States)

    Dinitz, Laura B.; Taketa, Richard A.

    2013-01-01

    This paper describes and demonstrates the integration of two geospatial decision-support systems for natural-hazard risk assessment and management. Hazus is a risk-assessment tool developed by the Federal Emergency Management Agency to identify risks and estimate the severity of risk from natural hazards. The Land Use Portfolio Model (LUPM) is a risk-management tool developed by the U.S. Geological Survey to evaluate plans or actions intended to reduce risk from natural hazards. We analysed three mitigation policies for one earthquake scenario in the San Francisco Bay area to demonstrate the added value of using Hazus and the LUPM together. The demonstration showed that Hazus loss estimates can be input to the LUPM to obtain estimates of losses avoided through mitigation, rates of return on mitigation investment, and measures of uncertainty. Together, they offer a more comprehensive approach to help with decisions for reducing risk from natural hazards.

  13. Measurement and Modelling of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Heiselberg, Per; Kalyanova, Olena; Jensen, Rasmus Lund

    2008-01-01

    Air flow rate in a naturally ventilated double skin façade (DSF) is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes the results of two different methods to measure the air flow in a full...... by the thermal simulation program, BSim, based on measured weather boundary conditions are compared to the measured air temperature, temperature gradient and mass flow rate in the DSF cavity. The results show that it is possible to predict the temperature distribution and airflow in the DSF although some......-scale outdoor test facility with a naturally ventilated double skin façade. Although both methods are difficult to use under such dynamic air flow conditions, they show reasonable agreement and can be used for experimental validation of numerical models of natural ventilation air flow in DSF. Simulations...

  14. Development of Modified Incompressible Ideal Gas Model for Natural Draft Cooling Tower Flow Simulation

    Science.gov (United States)

    Hyhlík, Tomáš

    2018-06-01

    The article deals with the development of incompressible ideal gas like model, which can be used as a part of mathematical model describing natural draft wet-cooling tower flow, heat and mass transfer. It is shown, based on the results of a complex mathematical model of natural draft wet-cooling tower flow, that behaviour of pressure, temperature and density is very similar to the case of hydrostatics of moist air, where heat and mass transfer in the fill zone must be taken into account. The behaviour inside the cooling tower is documented using density, pressure and temperature distributions. The proposed equation for the density is based on the same idea like the incompressible ideal gas model, which is only dependent on temperature, specific humidity and in this case on elevation. It is shown that normalized density difference of the density based on proposed model and density based on the nonsimplified model is in the order of 10-4. The classical incompressible ideal gas model, Boussinesq model and generalised Boussinesq model are also tested. These models show deviation in percentages.

  15. Development of Modified Incompressible Ideal Gas Model for Natural Draft Cooling Tower Flow Simulation

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš

    2018-01-01

    Full Text Available The article deals with the development of incompressible ideal gas like model, which can be used as a part of mathematical model describing natural draft wet-cooling tower flow, heat and mass transfer. It is shown, based on the results of a complex mathematical model of natural draft wet-cooling tower flow, that behaviour of pressure, temperature and density is very similar to the case of hydrostatics of moist air, where heat and mass transfer in the fill zone must be taken into account. The behaviour inside the cooling tower is documented using density, pressure and temperature distributions. The proposed equation for the density is based on the same idea like the incompressible ideal gas model, which is only dependent on temperature, specific humidity and in this case on elevation. It is shown that normalized density difference of the density based on proposed model and density based on the nonsimplified model is in the order of 10-4. The classical incompressible ideal gas model, Boussinesq model and generalised Boussinesq model are also tested. These models show deviation in percentages.

  16. Self-pressurization analysis of the natural circulation integral nuclear reactor using a new dynamic model

    Directory of Open Access Journals (Sweden)

    Ali Farsoon Pilehvar

    2018-06-01

    Full Text Available Self-pressurization analysis of the natural circulation integral nuclear reactor through a new dynamic model is studied. Unlike conventional pressurized water reactors, this reactor type controls the system pressure using saturated coolant water in the steam dome at the top of the pressure vessel. Self-pressurization model is developed based on conservation of mass, volume, and energy by predicting the condensation that occurs in the steam dome and the flashing inside the chimney using the partial differential equation. A simple but functional model is adopted for the steam generator. The obtained results indicate that the variable measurement is consistent with design data and that this new model is able to predict the dynamics of the reactor in different situations. It is revealed that flashing and condensation power are in direct relation with the stability of the system pressure, without which pressure convergence cannot be established. Keywords: Condensation Power, Flashing Phenomenon, Natural Circulation, Self-Pressurization, Small Modular Reactor

  17. Radionuclide migration in the geosphere: modelling of the natural analogue of needle's eye

    International Nuclear Information System (INIS)

    Doublet, R.; Jamet, P.; Lachassagne, P.; Ledoux, E.

    1990-01-01

    The study of the natural analogue of Needle's Eye (Scotland) has covered a three years period. It involved an important field and laboratory work, though delicate considering the peculiar site constraints (which is a natural reserve). The collaboration between BGS and SURRC geologists and geochemists on the one hand, and the modelling team of CIG on the other hand made it possible to collate an adequate and consistent database prior to a fruiful modelling work. In conclusion, the work that has been carried out enlights the applicability of a coupled model to a real case. This approach could be extended to other case studies. However, an important work remains to be done in order to strenghten the first encouraging results of the Needle's Eye model. This work is part of the community programme Mirage

  18. Development of natural radiation model for evaluation of background radiation in radiation portal monitor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Lee, Jin Hyung; Moon, Myung Kook [Radioisotope Research and Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-11-15

    In ports and airports, radiation portal monitors (RPM) are deployed to detect illicit radioactive materials. Detected gamma rays in a RPM include background radiation and radiation from a freight. As a vehicle moves through the RPM, the vehicle causes the fluctuations in the natural background radiation signal, which ranges of up to 30%. The fluctuation increases the uncertainty of detection signal and can be a cause of RPM false alarm. Therefore, it is important to evaluate background radiation as well as radiation from a container. In this paper, a natural background radiation model was developed to evaluate RPM. To develop natural background radiation model, a Monte Carlo simulation was performed and compared with experimental measurements from a RPM for {sup 40}K, {sup 232}Th series, and {sup 235}U series, which are major sources of natural background radiation. For a natural radiation source, we considered a cylindrical soil volume with 300 m radius and 1 m depth, which was estimated as the maximum range affecting the RPM by MCNP6 simulation. The volume source model was converted to surface source by using MCNP SSW card for computational efficiency. The computational efficiency of the surface source model was improved to approximately 200 times better than that of the volume source model. The surface source model is composed of a hemisphere with 20 m radius in which the RPM and container are modelled. The natural radiation spectrum from the simulation was best fitted to the experimental measurement when portions of {sup 40}K, {sup 232}Th series, and {sup 235}U series were 0.75, 0.0636, and 0.0552 Bq·g{sup -1}, respectively. For gross counting results, the difference between simulation and experiment was around 5%. The background radiation model was used to evaluate background suppression from a 40 ft container with 7.2 m·s{sup -1} speed. In further study, background models and freight models for RPM in real container ports will be developed and applied to

  19. A new modeling method for natural PWSCC cracking simulation in a dissimilar metal weld

    International Nuclear Information System (INIS)

    Xu, Heqin; Mahmoud, Samer; Nana, Ashok; Killian, Doug

    2014-01-01

    Cracks found in a nuclear power plant reactor coolant system (RCS), such as primary water stress corrosion cracking (PWSCC) and intergranular stress corrosion cracking (IGSCC), usually have natural crack front shapes that can be very different from the idealized semi-elliptical or rectangular shapes considered in engineering handbooks and other analytical solutions based on limited shapes. Simplifications towards semi-elliptical shape or rectangular shape may potentially introduce unnecessary conservatism when the simplified shape has to contain the actual crack shape. On the other hand, it is very time-consuming to create a three-dimensional (3D) finite element (FE) model to simulate crack propagation in a natural shape using existing public-domain software like ABAQUS or ANSYS. In this study, a local deformation-based mesh-mapping (LDMM) method is proposed to model cracks with a natural front shape in any 3D structures. This methodology is first applied to model circumferential surface cracks with a natural crack front shape in the cross-sectional plane of a cylinder. The proposed new method can be applied to simulate both shallow and deep cracks. Also discussed in this paper is a direct method to reproduce welding residual stresses in the crack model using temperature fields combined with other sustained loads to predict crack propagations. With this novel LDMM method, natural crack fronts and non-planar crack faces can be easily modeled. The proposed new method can be used to generate a high-quality finite element model that can be used for both linear-elastic fracture mechanics (LEFM) and elastic–plastic fracture mechanics (EPFM) analyses. The study case illustrates that the proposed LDMM method is easy to implement and more efficient than the existing commercial software

  20. Models for calibration of radiometric probes for measurement of natural radioactivity of rocks

    International Nuclear Information System (INIS)

    Czubek, J.A.; Lenda, A.

    1978-01-01

    The physical problems connected with the depth of investigation in the natural gamma-ray log measurements in the rocks are solved. The primary and the scattered radiation from gamma-ray lines of potassium, uranium and thorium series have been considered. The scattered radiation has been taken into account using the build-up factor approximation. The dimensions of rock models are calculated assuming the cylindrical form. Some recommendations for the realization of such models using the concrete mixtures are given. (author)

  1. The potential of artificial aging for modelling of natural aging processes of ballpoint ink.

    Science.gov (United States)

    Weyermann, Céline; Spengler, Bernhard

    2008-08-25

    Artificial aging has been used to reproduce natural aging processes in an accelerated pace. Questioned documents were exposed to light or high temperature in a well-defined manner in order to simulate an increased age. This may be used to study the aging processes or to date documents by reproducing their aging curve. Ink was studied especially because it is deposited on the paper when a document, such as a contract, is produced. Once on the paper, aging processes start through degradation of dyes, solvents drying and resins polymerisation. Modelling of dye's and solvent's aging was attempted. These processes, however, follow complex pathways, influenced by many factors which can be classified as three major groups: ink composition, paper type and storage conditions. The influence of these factors is such that different aging states can be obtained for an identical point in time. Storage conditions in particular are difficult to simulate, as they are dependent on environmental conditions (e.g. intensity and dose of light, temperature, air flow, humidity) and cannot be controlled in the natural aging of questioned documents. The problem therefore lies more in the variety of different conditions a questioned document might be exposed to during its natural aging, rather than in the simulation of such conditions in the laboratory. Nevertheless, a precise modelling of natural aging curves based on artificial aging curves is obtained when performed on the same paper and ink. A standard model for aging processes of ink on paper is therefore presented that is based on a fit of aging curves to a power law of solvent concentrations as a function of time. A mathematical transformation of artificial aging curves into modelled natural aging curves results in excellent overlap with data from real natural aging processes.

  2. Naturally light neutrinos in the flipped SU(5)xU(1) superstring model

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, I.; Rizos, J. (Centre de Physique Theorique, Ecole Polytechnique, 91 - Palaiseau (France)); Tamvakis, K. (Physics Dept., Univ. Ioannina (Greece))

    1992-04-16

    We analyze the SU(5)xU(1)'xU(1){sup 4}xSO(10)xSU(4) superstring model, taking into account non-renormalizable superpotential interactions up to sixth order, and find that all neutrinos stay naturally light within the experimental mass bounds. (orig.).

  3. Naturally ventilated double-skin façade in modeling and experiments

    DEFF Research Database (Denmark)

    Dama, Alessandro; Angeli, Diego; Larsen, Olena Kalyanova

    2017-01-01

    Highlights •An experimental validation of a model, developed for integration of DSF in Building Simulation tools, is given. •The validation was based on heat removed by natural ventilation, which is the main parameter in passive cooling systems. •A good degree of correlation was found between the...

  4. Reactor modeling and process analysis for partial oxidation of natural gas

    NARCIS (Netherlands)

    Albrecht, B.A.

    2004-01-01

    This thesis analyses a novel process of partial oxidation of natural gas and develops a numerical tool for the partial oxidation reactor modeling. The proposed process generates syngas in an integrated plant of a partial oxidation reactor, a syngas turbine and an air separation unit. This is called

  5. Dynamic model to tune a climate control algorithm in pig houses with natural ventilation

    NARCIS (Netherlands)

    Klooster, van 't C.E.; Bontsema, J.; Salomons, L.

    1995-01-01

    Algorithms for environmental control in livestock buildings have to be tuned for optimum response of actuators. For tuning, a simple, but dynamic, climate model for a pig house was formulated and validated to predict the
    environmental changes in a pig house with natural ventilation under varying

  6. Towards Control-Oriented Modeling of Natural Gas-Diesel RCCI Combustion

    NARCIS (Netherlands)

    Bekdemir, C.; Baert, R.; Willems, F.; Somers, B.

    2015-01-01

    For natural gas (NG)-diesel RCCI, a multi-zonal, detailed chemistry modeling approach is presented. This dual fuel combustion process requires further understanding of the ignition and combustion processes to maximize thermal efficiency and minimize (partially) unburned fuel emissions. The

  7. Multi-criteria decision models for forestry and natural resources management: an annotated bibliography

    Science.gov (United States)

    Joseph E. de Steiguer; Leslie Liberti; Albert Schuler; Bruce Hansen

    2003-01-01

    Foresters and natural resource managers must balance conflicting objectives when developing land-management plans. Conflicts may encompass economic, environmental, social, cultural, technical, and aesthetic objectives. Selecting the best combination of management uses from numerous objectives is difficult and challenging. Multi-Criteria Decision Models (MCDM) provide a...

  8. Statistical Models for Disaggregation and Reaggregation of Natural Gas Consumption Data

    Czech Academy of Sciences Publication Activity Database

    Brabec, Marek; Konár, Ondřej; Malý, Marek; Kasanický, Ivan; Pelikán, Emil

    2015-01-01

    Roč. 42, č. 5 (2015), s. 921-937 ISSN 0266-4763 Institutional support: RVO:67985807 Keywords : natural gas consumption * semiparametric model * standardized load profiles * aggregation * disaggregation * 62P30 Subject RIV: BB - Applied Statistics , Operational Research Impact factor: 0.419, year: 2015

  9. Preservice Biology Teachers' Conceptions about the Tentative Nature of Theories and Models in Biology

    Science.gov (United States)

    Reinisch, Bianca; Krüger, Dirk

    2018-01-01

    In research on the nature of science, there is a need to investigate the role and status of different scientific knowledge forms. Theories and models are two of the most important knowledge forms within biology and are the focus of this study. During interviews, preservice biology teachers (N = 10) were asked about their understanding of theories…

  10. Towards control-oriented modeling of natural gas-diesel RCCI combustion

    NARCIS (Netherlands)

    Bekdemir, C.; Baert, R.S.G.; Willems, F.P.T.; Somers, L.M.T.

    2015-01-01

    For natural gas (NG)-diesel RCCI, a multi-zonal, detailed chemistry modeling approach is presented. This dual fuel combustion process requires further understanding of the ignition and combustion processes to maximize thermal efficiency and minimize (partially) unburned fuel emissions. The

  11. Integrating social science into empirical models of coupled human and natural systems

    Science.gov (United States)

    Jeffrey D. Kline; Eric M. White; A Paige Fischer; Michelle M. Steen-Adams; Susan Charnley; Christine S. Olsen; Thomas A. Spies; John D. Bailey

    2017-01-01

    Coupled human and natural systems (CHANS) research highlights reciprocal interactions (or feedbacks) between biophysical and socioeconomic variables to explain system dynamics and resilience. Empirical models often are used to test hypotheses and apply theory that represent human behavior. Parameterizing reciprocal interactions presents two challenges for social...

  12. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural
    decomposition and transformation of dead plant and animal matter. The fresh
    organic matter (e.g. plant leaves or animal debris) is decomposed and
    transformed by microbial activity. As such, NOM is found

  13. Natural Model based Design in Context: an Effective Method for Environmental Problems

    Directory of Open Access Journals (Sweden)

    Eric D. Kameni

    2017-10-01

    Full Text Available Analyzing complex problem domains is not easy. Simulation tools support decision makers to find the best policies. Model-based system development is an approach where a model of the application domain is the central driving force when designing simulation tools. State-of-the-art techniques however still require both expert knowledge of the application domain and the implementation techniques as provided by ICT (such as multilevel agent technology. Domain experts, however, usually do not master ICT sufficiently. Modeling is more insightful for the domain expert when its goal is to formalize the language being used in that domain as a semi-natural language. At the meta level, this language describes the main concepts of the type of application domain. The model then is a concretization of this meta model. The main focus of this article is (1 to propose a natural-language-based approach to modeling application domains, (2 to show how these models can be transformed systematically into computational models, and (3 to propose the tool TiC (Tool in Context that supports the domain expert when developing a model and generating a simulation tool. Our research methodology is based on Design Science. We verify our approach by describing the various transformation steps in detail, and by demonstrating the way of working via a sample session applying a real problem of Laf Forest Reserve deforestation in North Cameroon.

  14. On theoretical models of gene expression evolution with random genetic drift and natural selection.

    Directory of Open Access Journals (Sweden)

    Osamu Ogasawara

    2009-11-01

    Full Text Available The relative contributions of natural selection and random genetic drift are a major source of debate in the study of gene expression evolution, which is hypothesized to serve as a bridge from molecular to phenotypic evolution. It has been suggested that the conflict between views is caused by the lack of a definite model of the neutral hypothesis, which can describe the long-run behavior of evolutionary change in mRNA abundance. Therefore previous studies have used inadequate analogies with the neutral prediction of other phenomena, such as amino acid or nucleotide sequence evolution, as the null hypothesis of their statistical inference.In this study, we introduced two novel theoretical models, one based on neutral drift and the other assuming natural selection, by focusing on a common property of the distribution of mRNA abundance among a variety of eukaryotic cells, which reflects the result of long-term evolution. Our results demonstrated that (1 our models can reproduce two independently found phenomena simultaneously: the time development of gene expression divergence and Zipf's law of the transcriptome; (2 cytological constraints can be explicitly formulated to describe long-term evolution; (3 the model assuming that natural selection optimized relative mRNA abundance was more consistent with previously published observations than the model of optimized absolute mRNA abundances.The models introduced in this study give a formulation of evolutionary change in the mRNA abundance of each gene as a stochastic process, on the basis of previously published observations. This model provides a foundation for interpreting observed data in studies of gene expression evolution, including identifying an adequate time scale for discriminating the effect of natural selection from that of random genetic drift of selectively neutral variations.

  15. The economics of natural gas infrastructure investments. Theory and model-based analysis for Europe

    Energy Technology Data Exchange (ETDEWEB)

    Lochner, Stefan

    2012-07-01

    Changing supply structures, security of supply threats and efforts to eliminate bottlenecks and increase competition in the European gas market potentially warrant infrastructure investments. However, which investments are actually efficient is unclear. From a theoretical perspective, concepts from other sectors regarding the estimation of congestion cost and efficient investment can be applied - with some extensions - to natural gas markets. Investigations in a simple analytical framework, thereby, show that congestion does not necessarily imply that investment is efficient, and that there are multiple interdependencies between investments in different infrastructure elements (pipeline grid, gas storage, import terminals for liquefied natural gas (LNG)) which need to be considered in an applied analysis. Such interdependencies strengthen the case for a model-based analysis. An optimization model minimizing costs can illustrate the first-best solution with respect to investments in natural gas infrastructure; gas market characteristics such as temperature-dependent stochasticity of demand or the lumpiness of investments can be included. Scenario analyses help to show the effects of changing the underlying model presumption. Hence, results are projections subject to data and model assumption - and not forecasts. However, as they depict the optimal, cost-minimizing outcome, results provide a guideline to policymakers and regulators regarding the desirable market outcome. A stochastic mixed-integer dispatch and investment model for the European natural gas infrastructure is developed as an optimization model taking the theoretical inter-dependencies into account. It is based on an extensive infrastructure database including long-distance transmission pipelines, LNG terminals and gas storage sites with a high level of spatial granularity. It is parameterized with assumptions on supply and demand developments as well as empirically derived infrastructure extension costs

  16. Integrated Spatial Modeling using Geoinformatics: A Prerequisite for Natural Resources Management

    Science.gov (United States)

    Katpatal, Y. B.

    2014-12-01

    Every natural system calls for complete visualization for its holistic and sustainable development. Many a times, especially in developing countries, the approaches deviate from this basic paradigm and results in ineffective management of the natural resources. This becomes more relevant in these countries which are witnessing heavy exodus of the rural population to urban areas increasing the pressures on the basic commodities. Spatial technologies which provide the opportunity to enhance the knowledge visualization of the policy makers and administrators which facilitates technical and scientific management of the resources. Increasing population has created negative impacts on the per capita availability of several resources, which has been well accepted in the statistical records of several developing countries. For instance, the per capita availability of water in India has decreased substantially in last decade and groundwater depletion is on the rise. There is hence a need of tool which helps in restoring the resource through visualization and evaluation temporally. Geological parameters play an important role in operation of several natural systems and earth sciences parameters may not be ignored. Spatial technologies enables application of 2D as well as 3D modeling taking into account variety of natural parameters related to diverse areas. The paper presents case studies where spatial technology has helped in not only understanding the natural systems but also providing solutions, especially in Indian context. The case studies relate to Groundwater Management, Watershed and Basin Management, Groundwater recharge, Environment sustainability using spatial technology. Key Words: Spatial model, Groundwater, Hydrogeology, Geoinformatics, Sustainable Development.

  17. Modelling seasonal variations of natural radioactivity in soils: A case study in southern Italy

    Science.gov (United States)

    Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; Rosa, Rosanna De; Scarciglia, Fabio; Buttafuoco, Gabriele

    2016-12-01

    The activity of natural radionuclides in soil has become an environmental concern for local public and national authorities because of the harmful effects of radiation exposure on human health. In this context, modelling and mapping the activity of natural radionuclides in soil is an important research topic. The study was aimed to model, in a spatial sense, the soil radioactivity in an urban and peri-urban soils area in southern Italy to analyse the seasonal influence on soil radioactivity. Measures of gamma radiation naturally emitted through the decay of radioactive isotopes (potassium, uranium and thorium) were analysed using a geostatistical approach to map the spatial distribution of soil radioactivity. The activity of three radionuclides was measured at 181 locations using a high-resolution ?-ray spectrometry. To take into account the influence of season, the measurements were carried out in summer and in winter. Activity data were analysed by using a geostatistical approach and zones of relatively high or low radioactivity were delineated. Among the main processes which influence natural radioactivity such as geology, geochemical, pedological, and ecological processes, results of this study showed a prominent control of radio-emission measurements by seasonal changes. Low natural radioactivity levels were measured in December associated with winter weather and moist soil conditions (due to high rainfall and low temperature), and higher activity values in July, when the soil was dry and no precipitations occurred.

  18. Deformation Behavior between Hydraulic and Natural Fractures Using Fully Coupled Hydromechanical Model with XFEM

    Directory of Open Access Journals (Sweden)

    Fei Liu

    2017-01-01

    Full Text Available There has been a growing consensus that preexisting natural fractures play an important role during stimulation. A novel fully coupled hydromechanical model using extended finite element method is proposed. This directly coupled scheme avoids the cumbersome process during calculating the fluid pressure in complicated fracture networks and translating into an equivalent nodal force. Numerical examples are presented to simulate the hydraulic fracture propagation paths for simultaneous multifracture treatments with properly using the stress shadow effects for horizontal wells and to reveal the deformation response and interaction mechanism between hydraulic induced fracture and nonintersected natural fractures at orthotropic and nonorthotropic angles. With the stress shadow effects, the induced hydraulic flexural fracture deflecting to wellbore rather than transverse fracture would be formed during the progress of simultaneous fracturing for a horizontal well. The coupled hydromechanical simulation reveals that the adjacent section to the intersection is opened and the others are closed for orthogonal natural fracture, while the nonorthogonal natural fracture is activated near the intersection firstly and along the whole section with increasing perturbed stresses. The results imply that the induced hydraulic fracture tends to cross orthotropic natural fracture, while it is prior to being arrested by the nonorthotropic natural fracture.

  19. Preliminary model validation for integral stability behavior in molten salt natural circulation

    International Nuclear Information System (INIS)

    Cai Chuangxiong; He Zhaozhong; Chen Kun

    2017-01-01

    Passive safety system is an important characteristic of Fluoride-Salt-Cooled High-Temperature Reactor (FHR). In order to remove the decay heat, a direct reactor auxiliary cooling system (DRACS) which uses the passive safety technology is proposed to the FHR as the ultimate heat sink. The DRACS is relying on the natural circulation, so the study of molten salt natural circulation plays an important role at TMSR. A high-temperature molten salt natural circulation test loop has been designed and constructed at the TMSR center of the Chinese Academy of Sciences (CAS) to understand the characteristics of the natural circulation and verify the design model. It adopts nitrate salt as the working fluid to simulate fluoride salts, and uses air as the ultimate heat sink. The test shows the operation very well and has a very nice performance, the Heat transfer coefficients (salt-salt or salt-air), power of the loop, heat loss of molten salt pool (or molten salt pipe or air cooling tower), starting time of the loop, flow rate that can be verified in this loop. A series of experiments have been done and the results show that the experimental data are well matched with the design data. This paper aims at analyzing the molten salt circulation model, studying the characteristics of the natural circulation, and verifying the Integral stability behavior by three different natural circulation experiments. Also, the experiment is going on, and more experiments will been carry out to study the molten salt natural circulation for optimizing the design. (author)

  20. Recent Progress in Understanding Natural-Hazards-Generated TEC Perturbations: Measurements and Modeling Results

    Science.gov (United States)

    Komjathy, A.; Yang, Y. M.; Meng, X.; Verkhoglyadova, O. P.; Mannucci, A. J.; Langley, R. B.

    2015-12-01

    Natural hazards, including earthquakes, volcanic eruptions, and tsunamis, have been significant threats to humans throughout recorded history. The Global Positioning System satellites have become primary sensors to measure signatures associated with such natural hazards. These signatures typically include GPS-derived seismic deformation measurements, co-seismic vertical displacements, and real-time GPS-derived ocean buoy positioning estimates. Another way to use GPS observables is to compute the ionospheric total electron content (TEC) to measure and monitor post-seismic ionospheric disturbances caused by earthquakes, volcanic eruptions, and tsunamis. Research at the University of New Brunswick (UNB) laid the foundations to model the three-dimensional ionosphere at NASA's Jet Propulsion Laboratory by ingesting ground- and space-based GPS measurements into the state-of-the-art Global Assimilative Ionosphere Modeling (GAIM) software. As an outcome of the UNB and NASA research, new and innovative GPS applications have been invented including the use of ionospheric measurements to detect tiny fluctuations in the GPS signals between the spacecraft and GPS receivers caused by natural hazards occurring on or near the Earth's surface.We will show examples for early detection of natural hazards generated ionospheric signatures using ground-based and space-borne GPS receivers. We will also discuss recent results from the U.S. Real-time Earthquake Analysis for Disaster Mitigation Network (READI) exercises utilizing our algorithms. By studying the propagation properties of ionospheric perturbations generated by natural hazards along with applying sophisticated first-principles physics-based modeling, we are on track to develop new technologies that can potentially save human lives and minimize property damage. It is also expected that ionospheric monitoring of TEC perturbations might become an integral part of existing natural hazards warning systems.

  1. Dynamic model of YGN 3 and 4 steam generators for natural circulation mode

    International Nuclear Information System (INIS)

    Sohn, Jong Joo

    1995-02-01

    A dynamic model for the secondary side of Yonggwang nuclear power plant units 3 and 4 (YGN 3 and 4) steam generator model is developed to improve the accuracy of the present performance analysis code. The new model is based on the one-dimensional three region model to predict the local quality and void fraction distribution along the U-tube length. The local quality concept is used instead of the Wilson bubble rise correlation to simulate the steam generators in the natural circulation mode. The new model can be applicable to the plants in the power operation modes such as load maneuvering transients in which the steam generator internal flow is maintained in the natural circulation mode. To validate the new model, the code predictions are compared with the actual plant data measured for the selected load maneuvering tests performed during the YGN units 3 power ascension test period. The results from the improved model show better agreement with the plant data than those from the present code. Especially, the new model's capability of accurately simulating the steam generator water level behavior during the fast transients such as a large load rejection event is demonstrated

  2. A lumped parameter core dynamics model for MTR type research reactors under natural convection regime

    International Nuclear Information System (INIS)

    Ardaneh, Kazem; Zaferanlouei, Salman

    2013-01-01

    Highlights: ► A model is presented to simulate the reactivity insertion transient in MTR reactors. ► Transient dynamics of IAEA 10 MW MTR type research reactor are evaluated. ► Maximum unprotected reactivity insertion for safe condition is calculated. ► The model predictions are validated with corresponding results in the literature. - Abstract: On the basis of lumped parameter modeling of both the kinetic and thermal–hydraulic effects, a reasonably accurate simplified model has been developed to predict the dynamic response of MTR reactors following to an unprotected reactivity insertion under natural convection regime. By this model the reactor transient behavior at a given initial steady-state can be solved by a set of ordinary differential equations. The model predictions have an acceptable consent with corresponding results of reactivity insertion transients analyzed in the literature. The inherent safety characteristics of MTR research reactors utilizing natural convection is clearly demonstrated by the expanded model. The safety margin of reactor operating is selected ONB condition and thereby the proposed model determines that any slight increase in the value of $0.73 for inserted reactivity will cause the maximum cladding surface temperature to exceed the ONB condition

  3. Concept of CFD model of natural draft wet-cooling tower flow

    Directory of Open Access Journals (Sweden)

    Hyhlík T.

    2014-03-01

    Full Text Available The article deals with the development of CFD model of natural draft wet-cooling tower flow. The physical phenomena taking place within a natural draft wet cooling tower are described by the system of conservation law equations along with additional equations. The heat and mass transfer in the counterflow wet-cooling tower fill are described by model [1] which is based on the system of ordinary differential equations. Utilization of model [1] of the fill allows us to apply commonly measured fill characteristics as shown by [2].The boundary value problem resulting from the fill model is solved separately. The system of conservation law equations is interlinked with the system of ordinary differential equations describing the phenomena occurring in the counterflow wet-cooling tower fill via heat and mass sources and via boundary conditions. The concept of numerical solution is presented for the quasi one dimensional model of natural draft wet-cooling tower flow. The simulation results are shown.

  4. A new model for the accurate calculation of natural gas viscosity

    Directory of Open Access Journals (Sweden)

    Xiaohong Yang

    2017-03-01

    Full Text Available Viscosity of natural gas is a basic and important parameter, of theoretical and practical significance in the domain of natural gas recovery, transmission and processing. In order to obtain the accurate viscosity data efficiently at a low cost, a new model and its corresponding functional relation are derived on the basis of the relationship among viscosity, temperature and density derived from the kinetic theory of gases. After the model parameters were optimized using a lot of experimental data, the diagram showing the variation of viscosity along with temperature and density is prepared, showing that: ① the gas viscosity increases with the increase of density as well as the increase of temperature in the low density region; ② the gas viscosity increases with the decrease of temperature in high density region. With this new model, the viscosity of 9 natural gas samples was calculated precisely. The average relative deviation between these calculated values and 1539 experimental data measured at 250–450 K and 0.10–140.0 MPa is less than 1.9%. Compared with the 793 experimental data with a measurement error less than 0.5%, the maximum relative deviation is less than 0.98%. It is concluded that this new model is more advantageous than the previous 8 models in terms of simplicity, accuracy, fast calculation, and direct applicability to the CO2 bearing gas samples.

  5. Natural resource damage assessment models for Great Lakes, coastal, and marine environments

    International Nuclear Information System (INIS)

    French, D.P.; Reed, M.

    1993-01-01

    A computer model of the physical fates, biological effects, and economic damages resulting from releases of oil and other hazardous materials has been developed by Applied Science Associates to be used in Type A natural resource damage assessments under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). Natural resource damage assessment models for great lakes environments and for coastal and marine environments will become available. A coupled geographical information system allows gridded representation of complex coastal boundaries, variable bathymetry, shoreline types, and multiple biological habitats. The physical and biological models are three dimensional. Direct mortality from toxic concentrations and oiling, impacts of habitat loss, and food web losses are included in the model. Estimation of natural resource damages is based both on the lost value of injured resources and on the costs of restoring or replacing those resources. The models are implemented on a personal computer, with a VGA graphical user interface. Following public review, the models will become a formal part of the US regulatory framework. The models are programmed in a modular and generic fashion, to facilitate transportability and application to new areas. The model has several major components. Physical fates and biological effects submodels estimate impacts or injury resulting from a spill. The hydrodynamic submodel calculates currents that transport contaminant(s) or organisms. The compensable value submodel values injuries to help assess damages. The restoration submodel determines what restoration actions will most cost-effectively reduce injuries as measured by compensable values. Injury and restoration costs are assessed for each of a series of habitats (environments) affected by the spill. Environmental, chemical, and biological databases supply required information to the model for computing fates and effects (injury)

  6. Forecasting total natural-gas consumption in Spain by using the stochastic Gompertz innovation diffusion model

    International Nuclear Information System (INIS)

    Gutierrez, R.; Nafidi, A.; Gutierrez Sanchez, R.

    2005-01-01

    The principal objective of the present study is to examine the possibilities of using a Gompertz-type innovation diffusion process as a stochastic growth model of natural-gas consumption in Spain, and to compare our results with those obtained, on the one hand, by stochastic logistic innovation modelling and, on the other, by using a stochastic lognormal growth model based on a non-innovation diffusion process. Such a comparison is carried out taking into account the macroeconomic characteristics and natural-gas consumption patterns in Spain, both of which reflect the current expansive situation characterizing the Spanish economy. From the technical standpoint a contribution is also made to the theory of the stochastic Gompertz Innovation diffusion process (SGIDP), as applied to the case in question. (author)

  7. Short-term airing by natural ventilation - modeling and control strategies.

    Science.gov (United States)

    Perino, M; Heiselberg, P

    2009-10-01

    The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates traditional mechanical ventilation components with natural ventilation devices, such as motorized windows and louvers. Among the various ventilation strategies that are currently available, buoyancy driven single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and IAQ control. However, in order to promote a wider applications of these systems, an improvement in the knowledge of their working principles and the availability of new design and simulation tools is necessary. In this context, the paper analyses and presents the results of a research that was aimed at developing and validating numerical models for the analysis of buoyancy driven single-sided natural ventilation systems. Once validated, these models can be used to optimize control strategies in order to achieve satisfactory indoor comfort conditions and IAQ. Practical Implications Numerical and experimental analyses have proved that short-term airing by intermittent ventilation is an effective measure to satisfactorily control IAQ. Different control strategies have been investigated to optimize the capabilities of the systems. The proposed zonal model has provided good performances and could be adopted as a design tool, while CFD simulations can be profitably used for detailed studies of the pollutant concentration distribution in a room and to address local discomfort problems.

  8. Kainic Acid-Induced Excitotoxicity Experimental Model: Protective Merits of Natural Products and Plant Extracts

    Directory of Open Access Journals (Sweden)

    Nur Shafika Mohd Sairazi

    2015-01-01

    Full Text Available Excitotoxicity is well recognized as a major pathological process of neuronal death in neurodegenerative diseases involving the central nervous system (CNS. In the animal models of neurodegeneration, excitotoxicity is commonly induced experimentally by chemical convulsants, particularly kainic acid (KA. KA-induced excitotoxicity in rodent models has been shown to result in seizures, behavioral changes, oxidative stress, glial activation, inflammatory mediator production, endoplasmic reticulum stress, mitochondrial dysfunction, and selective neurodegeneration in the brain upon KA administration. Recently, there is an emerging trend to search for natural sources to combat against excitotoxicity-associated neurodegenerative diseases. Natural products and plant extracts had attracted a considerable amount of attention because of their reported beneficial effects on the CNS, particularly their neuroprotective effect against excitotoxicity. They provide significant reduction and/or protection against the development and progression of acute and chronic neurodegeneration. This indicates that natural products and plants extracts may be useful in protecting against excitotoxicity-associated neurodegeneration. Thus, targeting of multiple pathways simultaneously may be the strategy to maximize the neuroprotection effect. This review summarizes the mechanisms involved in KA-induced excitotoxicity and attempts to collate the various researches related to the protective effect of natural products and plant extracts in the KA model of neurodegeneration.

  9. Advances and Challenges in Space-time Modelling of Natural Events

    CERN Document Server

    Porcu, Emilio; Schlather, Martin

    2012-01-01

    This book arises as the natural continuation of the International Spring School "Advances and Challenges in Space-Time modelling of Natural Events," which took place in Toledo (Spain) in March 2010. This Spring School above all focused on young researchers (Master students, PhD students and post-doctoral researchers) in academics, extra-university research and the industry who are interested in learning about recent developments, new methods and applications in spatial statistics and related areas, and in exchanging ideas and findings with colleagues.

  10. DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

    2002-12-31

    For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for

  11. Differential Dynamic Evolutionary Model of Emergency Financial Service Supply Chain in Natural Disaster Risk Management

    Directory of Open Access Journals (Sweden)

    Shujian Ma

    2016-01-01

    Full Text Available A government-market-public partnership (GMPP could be a feasible arrangement for providing insurance coverage for natural disaster. Firstly, we put forward GMPP management mode. Secondly, the emergency financial service supply chain for natural disaster risk is built from the view of supply chain. Finally, the objective of this paper is to obtain insights into the cooperative and competitive relationship in GMPP system. We establish the cooperative and competitive differential dynamic evolutionary models and prove the existence of equilibrium solutions in order to solve the coordination problems. In conclusion, the equilibrium solutions can be achieved among the insurers, the operating governments, and the public.

  12. Modelling prospects for in situ matrix diffusion at Palmottu natural analogue site, SW Finland

    International Nuclear Information System (INIS)

    Rasilainen, K.; Suksi, J.

    1994-01-01

    Concentration distributions of natural decay chains 4n+2 and 4n+3 in crystalline rock intersected by a natural fracture were measured. Calcite coating on the same fracture surface was dated. Material properties of the rock matrix, and nuclide concentrations in groundwater were measured. The interpretation of the concentration distributions is based on the classical matrix diffusion concept. Although support was obtained, this calibration exercise does not yet validate the model. Besides initial and boundary conditions, matrix properties are uncertain due to the small amount of rock material. Experimental sorption data was not available, but its importance and the need for systematic studies was demonstrated. (orig.) (10 refs., 5 figs., 5 tabs.)

  13. Advanced model for expansion of natural gas distribution networks based on geographic information systems

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Rosado, I.J.; Fernandez-Jimenez, L.A.; Garcia-Garrido, E.; Zorzano-Santamaria, P.; Zorzano-Alba, E. [La Rioja Univ., La Rioja (Spain). Dept. of Electrical Engineering; Miranda, V.; Montneiro, C. [Porto Univ., Porto (Portugal). Faculty of Engineering]|[Inst. de Engenharia de Sistemas e Computadores do Porto, Porto (Portugal)

    2005-07-01

    An advanced geographic information system (GIS) model of natural gas distribution networks was presented. The raster-based model was developed to evaluate costs associated with the expansion of electrical networks due to increased demand in the La Rioja region of Spain. The model was also used to evaluate costs associated with maintenance and amortization of the already existing distribution network. Expansion costs of the distribution network were modelled in various demand scenarios. The model also considered a variety of technical factors associated with pipeline length and topography. Soil and slope data from previous pipeline projects were used to estimate real costs per unit length of pipeline. It was concluded that results obtained by the model will be used by planners to select zones where expansion is economically feasible. 4 refs., 5 figs.

  14. A Cointegrated Regime-Switching Model Approach with Jumps Applied to Natural Gas Futures Prices

    Directory of Open Access Journals (Sweden)

    Daniel Leonhardt

    2017-09-01

    Full Text Available Energy commodities and their futures naturally show cointegrated price movements. However, there is empirical evidence that the prices of futures with different maturities might have, e.g., different jump behaviours in different market situations. Observing commodity futures over time, there is also evidence for different states of the underlying volatility of the futures. In this paper, we therefore allow for cointegration of the term structure within a multi-factor model, which includes seasonality, as well as joint and individual jumps in the price processes of futures with different maturities. The seasonality in this model is realized via a deterministic function, and the jumps are represented with thinned-out compound Poisson processes. The model also includes a regime-switching approach that is modelled through a Markov chain and extends the class of geometric models. We show how the model can be calibrated to empirical data and give some practical applications.

  15. Altering Height Data by Using Natural Logarithm as 3D Modelling Function for Reverse Engineering Application

    Science.gov (United States)

    Ilham Aminullah Abdulqawi, Nur; Salman Abu Mansor, Mohd

    2018-01-01

    The raw data extracted from reverse engineering based on vision mostly do not resemble the actual geometrical representation yet. Even though the higher object surface reflected the most visible light towards the camera and yield higher number of value based on Lambertian illumination model, this does not mean the curvature profile are always accurate. After all, there are many mathematical models to shape curvature profiles into the correct representation. However, one of the most appropriate models found is the natural logarithm function. The function itself has alteration properties towards the raw data generated from reverse engineering based on vision.

  16. Model of acceptance of a new type of beverage: application to natural sparkling red wine

    OpenAIRE

    Cristina Olarte; Jorge Pelegrín; Eva Reinares

    2017-01-01

    Wine is a traditional beverage with a saturated market, in which consumers are open to innovation. In this context, an innovative experience was launched to create a new natural sparkling red wine with a view to diversifying production and studying its acceptance. This paper uses an original acceptance model for new foods called the Cognitive-Affective-Normative (CAN) model. The model was tested on a sample of 500 Spanish consumers in a real-world test context and explains 64.1% of the intent...

  17. Uncertainties in radioecological assessment models-Their nature and approaches to reduce them

    International Nuclear Information System (INIS)

    Kirchner, G.; Steiner, M.

    2008-01-01

    Radioecological assessment models are necessary tools for estimating the radiation exposure of humans and non-human biota. This paper focuses on factors affecting their predictive accuracy, discusses the origin and nature of the different contributions to uncertainty and variability and presents approaches to separate and quantify them. The key role of the conceptual model, notably in relation to its structure and complexity, as well as the influence of the number and type of input parameters, are highlighted. Guidelines are provided to improve the degree of reliability of radioecological models

  18. MODELING THE PROCESSES OF CONTROL OF COMPLEXLY ORGANIZED “NATURE-SOCIETY” SYSTEMS

    Directory of Open Access Journals (Sweden)

    S. L. Turkov

    2017-01-01

    Full Text Available The report highlights some questions of modeling the processes of control for “naturesociety” systems. The purpose and common direction for using the results is to work out the “human-machine” systems of planning (or support for making the optimum decisions during realization of “Sustainable Development” conception as the official doctrine for the development of Russia (1996.The research has been based on: the new paradigm of system presentation of the world, the theory of “noosphere” by P.T. de Chardin, E. Le Roy, V.I. Vernadsky, “new theory of entropy” by A.N. Panchenkov (1999. The object of research is the class of Active Complexly organized “nature-society” systems; the subject – concepts of “balance” for integrated systems and Conception of “Sustainable Development”; the methods for researching are the Game-Theory modeling, the “Game against Nature”, coalition, cooperation etc according to condition for staging problems, games. During modeling this ensures the full integration of all accessible today natural sciences knowledge, as well as possibility to carry out computing operations of situation control for “naturesociety” systems.The research foresees execution of the following five stages of the problem study. Information modeling for possible structures of object (the starting field of knowledge is “geoecology”. The system analysis and synthesis of permissible dynamics and outside conditions of its development. The mathematical modeling for natural resources used at regional and local levels. The technological design work (the GIS-, GRID-technologies and artificial intellect systems for control of making decisions. The numerical experiments and checking the efficiency of models and algorithms. Methodically they are presented as a consecutively connected aggregate of “structure”, “functional” and “normative” models. A new – “geosystem” – approach offered to research the

  19. A Posteriori Comparison of Natural and Surgical Destabilization Models of Canine Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Maxim Moreau

    2013-01-01

    Full Text Available For many years Canis familiaris, the domestic dog, has drawn particular interest as a model of osteoarthritis (OA. Here, we optimized the dog model of experimental OA induced by cranial cruciate ligament sectioning. The usefulness of noninvasive complementary outcome measures, such as gait analysis for the limb function and magnetic resonance imaging for structural changes, was demonstrated in this model. Relationships were established between the functional impairment and the severity of structural changes including the measurement of cartilage thinning. In the dog model of naturally occurring OA, excellent test-retest reliability was denoted for the measurement of the limb function. A criterion to identify clinically meaningful responders to therapy was determined for privately owned dogs undergoing clinical trials. In addition, the recording of accelerometer-based duration of locomotor activity showed strong and complementary agreement with the biomechanical limb function. The translation potential of these models to the human OA condition is underlined. A preclinical testing protocol which combines the dog model of experimental OA induced by cranial cruciate ligament transection and the Dog model of naturally occurring OA offers the opportunity to further investigate the structural and functional benefits of disease-modifying strategies. Ultimately, a better prediction of outcomes for human clinical trials would be brought.

  20. Simplifying and upscaling water resources systems models that combine natural and engineered components

    Science.gov (United States)

    McIntyre, N.; Keir, G.

    2014-12-01

    Water supply systems typically encompass components of both natural systems (e.g. catchment runoff, aquifer interception) and engineered systems (e.g. process equipment, water storages and transfers). Many physical processes of varying spatial and temporal scales are contained within these hybrid systems models. The need to aggregate and simplify system components has been recognised for reasons of parsimony and comprehensibility; and the use of probabilistic methods for modelling water-related risks also prompts the need to seek computationally efficient up-scaled conceptualisations. How to manage the up-scaling errors in such hybrid systems models has not been well-explored, compared to research in the hydrological process domain. Particular challenges include the non-linearity introduced by decision thresholds and non-linear relations between water use, water quality, and discharge strategies. Using a case study of a mining region, we explore the nature of up-scaling errors in water use, water quality and discharge, and we illustrate an approach to identification of a scale-adjusted model including an error model. Ways forward for efficient modelling of such complex, hybrid systems are discussed, including interactions with human, energy and carbon systems models.

  1. A Posteriori Comparison of Natural and Surgical Destabilization Models of Canine Osteoarthritis

    Science.gov (United States)

    Pelletier, Jean-Pierre; d'Anjou, Marc-André; Blond, Laurent; Pelletier, Johanne-Martel; del Castillo, Jérôme R. E.

    2013-01-01

    For many years Canis familiaris, the domestic dog, has drawn particular interest as a model of osteoarthritis (OA). Here, we optimized the dog model of experimental OA induced by cranial cruciate ligament sectioning. The usefulness of noninvasive complementary outcome measures, such as gait analysis for the limb function and magnetic resonance imaging for structural changes, was demonstrated in this model. Relationships were established between the functional impairment and the severity of structural changes including the measurement of cartilage thinning. In the dog model of naturally occurring OA, excellent test-retest reliability was denoted for the measurement of the limb function. A criterion to identify clinically meaningful responders to therapy was determined for privately owned dogs undergoing clinical trials. In addition, the recording of accelerometer-based duration of locomotor activity showed strong and complementary agreement with the biomechanical limb function. The translation potential of these models to the human OA condition is underlined. A preclinical testing protocol which combines the dog model of experimental OA induced by cranial cruciate ligament transection and the Dog model of naturally occurring OA offers the opportunity to further investigate the structural and functional benefits of disease-modifying strategies. Ultimately, a better prediction of outcomes for human clinical trials would be brought. PMID:24288664

  2. Development of a transient calculation model for a closed sodium natural circulation loop

    International Nuclear Information System (INIS)

    Chang, Won Pyo; Ha, Kwi Seok; Jeong, Hae Yong; Heo, Sun; Lee, Yong Bum

    2003-09-01

    A natural circulation loop has usually adopted for a Liquid Metal Reactor (LMR) because of its high reliability. Up-rating of the current KALIMER capacity requires an additional PDRC to the existing PVCS to remove its decay heat under an accident. As the system analysis code currently used for LMR in Korea does not feature a stand alone capability to simulate a closed natural circulation loop, it is not eligible to be applied to PDRC. To supplement its limitation, a steady state calculation model had been developed during the first phase, and development of the transient model has successively carried out to close the present study. The developed model will then be coupled with the system analysis code, SSC-K to assess a long term cooling for the new conceptual design. The incompressibility assumption of sodium which allows the circuit to be modeled with a single loop flow, makes the model greatly simplified comparing with LWR. Some thermal-hydraulic models developed during this study can be effectively applied to other system analysis codes which require such component models, and the present development will also contribute to establishment of a code system for the LMR analysis

  3. Integrated modeling for optimized regional transportation with compressed natural gas fuel

    Directory of Open Access Journals (Sweden)

    Hossam A. Gabbar

    2016-03-01

    Full Text Available Transportation represents major energy consumption where fuel is considered as a primary energy source. Recent development in the vehicle technology revealed possible economical improvements when using natural gas as a fuel source instead of traditional gasoline. There are several fuel alternatives such as electricity, which showed potential for future long-term transportation. However, the move from current situation where gasoline vehicle is dominating shows high cost compared to compressed natural gas vehicle. This paper presents modeling and simulation methodology to optimize performance of transportation based on quantitative study of the risk-based performance of regional transportation. Emission estimation method is demonstrated and used to optimize transportation strategies based on life cycle costing. Different fuel supply scenarios are synthesized and evaluated, which showed strategic use of natural gas as a fuel supply.

  4. Accidental naturalism: criticism of a theoretical model of socio-ecological legitimacy

    Directory of Open Access Journals (Sweden)

    Santiago M. Cruzada

    2017-11-01

    Full Text Available This article proposes the need for a theoretical review on the current epistemological assumption that establishes the dichotomy nature-society as a cornerstone of a broad worldview for western contexts. We will discuss the anthropological perspectives that assume that in these spaces, generically without nuances, social practice and ideas are not constructed in such a close relationship to the environment, falling under a belief that nature exists outside the human will. We will debate the naive ethnological essentialism that position naturalism as a central model of a socio-european worldview, characterized by dualistic patterns that have enabled monistic paradigms of socio-ecological relationships to be established at the same time, and in contrast to this, in other parts of the world.

  5. MODELING THE AMBIENT CONDITION EFFECTS OF AN AIR-COOLED NATURAL CIRCULATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Rui; Lisowski, Darius D.; Bucknor, Matthew; Kraus, Adam R.; Lv, Qiuping

    2017-07-02

    The Reactor Cavity Cooling System (RCCS) is a passive safety concept under consideration for the overall safety strategy of advanced reactors such as the High Temperature Gas-Cooled Reactor (HTGR). One such variant, air-cooled RCCS, uses natural convection to drive the flow of air from outside the reactor building to remove decay heat during normal operation and accident scenarios. The Natural convection Shutdown heat removal Test Facility (NSTF) at Argonne National Laboratory (“Argonne”) is a half-scale model of the primary features of one conceptual air-cooled RCCS design. The facility was constructed to carry out highly instrumented experiments to study the performance of the RCCS concept for reactor decay heat removal that relies on natural convection cooling. Parallel modeling and simulation efforts were performed to support the design, operation, and analysis of the natural convection system. Throughout the testing program, strong influences of ambient conditions were observed in the experimental data when baseline tests were repeated under the same test procedures. Thus, significant analysis efforts were devoted to gaining a better understanding of these influences and the subsequent response of the NSTF to ambient conditions. It was determined that air humidity had negligible impacts on NSTF system performance and therefore did not warrant consideration in the models. However, temperature differences between the building exterior and interior air, along with the outside wind speed, were shown to be dominant factors. Combining the stack and wind effects together, an empirical model was developed based on theoretical considerations and using experimental data to correlate zero-power system flow rates with ambient meteorological conditions. Some coefficients in the model were obtained based on best fitting the experimental data. The predictive capability of the empirical model was demonstrated by applying it to the new set of experimental data. The

  6. Modeling aesthetics to support an ecosystem services approach for natural resource management decision making.

    Science.gov (United States)

    Booth, Pieter N; Law, Sheryl A; Ma, Jane; Buonagurio, John; Boyd, James; Turnley, Jessica

    2017-09-01

    This paper reviews literature on aesthetics and describes the development of vista and landscape aesthetics models. Spatially explicit variables were chosen to represent physical characteristics of natural landscapes that are important to aesthetic preferences. A vista aesthetics model evaluates the aesthetics of natural landscapes viewed from distances of more than 1000 m, and a landscape aesthetics model evaluates the aesthetic value of wetlands and forests within 1000 m from the viewer. Each of the model variables is quantified using spatially explicit metrics on a pixel-specific basis within EcoAIM™, a geographic information system (GIS)-based ecosystem services (ES) decision analysis support tool. Pixel values are "binned" into ranked categories, and weights are assigned to select variables to represent stakeholder preferences. The final aesthetic score is the weighted sum of all variables and is assigned ranked values from 1 to 10. Ranked aesthetic values are displayed on maps by patch type and integrated within EcoAIM. The response of the aesthetic scoring in the models was tested by comparing current conditions in a discrete area of the facility with a Development scenario in the same area. The Development scenario consisted of two 6-story buildings and a trail replacing natural areas. The results of the vista aesthetic model indicate that the viewshed area variable had the greatest effect on the aesthetics overall score. Results from the landscape aesthetics model indicate a 10% increase in overall aesthetics value, attributed to the increase in landscape diversity. The models are sensitive to the weights assigned to certain variables by the user, and these weights should be set to reflect regional landscape characteristics as well as stakeholder preferences. This demonstration project shows that natural landscape aesthetics can be evaluated as part of a nonmonetary assessment of ES, and a scenario-building exercise provides end users with a tradeoff

  7. Effects of the Ordering of Natural Selection and Population Regulation Mechanisms on Wright-Fisher Models.

    Science.gov (United States)

    He, Zhangyi; Beaumont, Mark; Yu, Feng

    2017-07-05

    We explore the effect of different mechanisms of natural selection on the evolution of populations for one- and two-locus systems. We compare the effect of viability and fecundity selection in the context of the Wright-Fisher model with selection under the assumption of multiplicative fitness. We show that these two modes of natural selection correspond to different orderings of the processes of population regulation and natural selection in the Wright-Fisher model. We find that under the Wright-Fisher model these two different orderings can affect the distribution of trajectories of haplotype frequencies evolving with genetic recombination. However, the difference in the distribution of trajectories is only appreciable when the population is in significant linkage disequilibrium. We find that as linkage disequilibrium decays the trajectories for the two different models rapidly become indistinguishable. We discuss the significance of these findings in terms of biological examples of viability and fecundity selection, and speculate that the effect may be significant when factors such as gene migration maintain a degree of linkage disequilibrium. Copyright © 2017 He et al.

  8. Numerical model for the solution of two-dimensional natural convection problems in arbitrary cavities

    International Nuclear Information System (INIS)

    Milioli, F.E.

    1985-01-01

    In this research work a numerical model for the solution of two-dimensional natural convection problems in arbitrary cavities of a Boussinesq fluid is presented. The conservation equations are written in a general curvilinear coordinate system which matches the irregular boundaries of the domain. The nonorthogonal system is generated by a suitable system of elliptic equations. The momentum and continuity equations are transformed from the Cartesian system to the general curvilinear system keeping the Cartesian velocity components as the dependent variables in the transformed domain. Finite difference equations are obtained for the contravariant velocity components in the transformed domain. The numerical calculations are performed in a fixed rectangular domain and both the Cartesian and the contravariant velocity components take part in the solutiomn procedure. The dependent variables are arranged on the grid in a staggered manner. The numerical model is tested by solving the driven flow in a square cavity with a moving side using a nonorthogoanl grid. The natural convenction in a square cavity, using an orthogonal and a nonorthogonal grid, is also solved for the model test. Also, the solution for the buoyancy flow between a square cylinder placed inside a circular cylinder is presented. The results of the test problems are compared with those available in the specialized literature. Finally, in order to show the generality of the model, the natural convection problem inside a very irregular cavity is presented. (Author) [pt

  9. An analytical and experimental investigation of natural circulation transients in a model pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Massoud, M

    1987-01-01

    Natural Circulation phenomena in a simulated PWR was investigated experimentally and analytically. The experimental investigation included determination of system characteristics as well as system response to the imposed transient under symmetric and asymmetric operations. System characteristics were used to obtain correlation for heat transfer coefficient in heat exchangers, system flow resistance, and system buoyancy heat. Asymmetric transients were imposed to study flow oscillation and possible instability. The analytical investigation encompassed development of mathematical model for single-phase, steady-state and transient natural circulation as well as modification of existing model for two-phase flow analysis of phenomena such as small break LOCA, high pressure coolant injection and pump coast down. The developed mathematical model for single-phase analysis was computer coded to simulate the imposed transients. The computer program, entitled ''Symmetric and Asymmetric Analysis of Single-Phase Flow (SAS),'' were employed to simulate the imposed transients. It closely emulated the system behavior throughout the transient and subsequent steady-state. Modifications for two-phase flow analysis included addition of models for once-through steam generator and electric heater rods. Both programs are faster than real time. Off-line, they can be used for prediction and training applications while on-line they serve for simulation and signal validation. The programs can also be used to determine the sensitivity of natural circulation behavior to variation of inputs such as secondary distribution and power transients.

  10. An analytical and experimental investigation of natural circulation transients in a model pressurized water reactor

    International Nuclear Information System (INIS)

    Massoud, M.

    1987-01-01

    Natural Circulation phenomena in a simulated PWR was investigated experimentally and analytically. The experimental investigation included determination of system characteristics as well as system response to the imposed transient under symmetric and asymmetric operations. System characteristics were used to obtain correlation for heat transfer coefficient in heat exchangers, system flow resistance, and system buoyancy heat. Asymmetric transients were imposed to study flow oscillation and possible instability. The analytical investigation encompassed development of mathematical model for single-phase, steady-state and transient natural circulation as well as modification of existing model for two-phase flow analysis of phenomena such as small break LOCA, high pressure coolant injection and pump coast down. The developed mathematical model for single-phase analysis was computer coded to simulate the imposed transients. The computer program, entitled ''Symmetric and Asymmetric Analysis of Single-Phase Flow (SAS),'' were employed to simulate the imposed transients. It closely emulated the system behavior throughout the transient and subsequent steady-state. Modifications for two-phase flow analysis included addition of models for once-through steam generator and electric heater rods. Both programs are faster than real time. Off-line, they can be used for prediction and training applications while on-line they serve for simulation and signal validation. The programs can also be used to determine the sensitivity of natural circulation behavior to variation of inputs such as secondary distribution and power transients

  11. Investigating and Modeling Ecosystem Response to an Experimental and a Natural Ice Storm

    Science.gov (United States)

    Fakhraei, H.; Driscoll, C. T.; Rustad, L.; Campbell, J. L.; Groffman, P.; Fahey, T.; Likens, G.; Swaminathan, R.

    2017-12-01

    the biogeochemical model, PnET-BGC. The model was calibrated to the study watersheds using observations from the natural and experimental ice storms. Future projections for ice storm events were estimated from an advanced climate model and applied to the calibrated PnET-BGC model to simulate future impacts of ice storms on the northern hardwood forests.

  12. Numerical Modeling of Methane Leakage from a Faulty Natural Gas Well into Fractured Tight Formations.

    Science.gov (United States)

    Moortgat, Joachim; Schwartz, Franklin W; Darrah, Thomas H

    2018-03-01

    Horizontal drilling and hydraulic fracturing have enabled hydrocarbon recovery from unconventional reservoirs, but led to natural gas contamination of shallow groundwaters. We describe and apply numerical models of gas-phase migration associated with leaking natural gas wells. Three leakage scenarios are simulated: (1) high-pressure natural gas pulse released into a fractured aquifer; (2) continuous slow leakage into a tilted fractured formation; and (3) continuous slow leakage into an unfractured aquifer with fluvial channels, to facilitate a generalized evaluation of natural gas transport from faulty natural gas wells. High-pressure pulses of gas leakage into sparsely fractured media are needed to produce the extensive and rapid lateral spreading of free gas previously observed in field studies. Transport in fractures explains how methane can travel vastly different distances and directions laterally away from a leaking well, which leads to variable levels of methane contamination in nearby groundwater wells. Lower rates of methane leakage (≤1 Mcf/day) produce shorter length scales of gas transport than determined by the high-pressure scenario or field studies, unless aquifers have low vertical permeabilities (≤1 millidarcy) and fractures and bedding planes have sufficient tilt (∼10°) to allow a lateral buoyancy component. Similarly, in fractured rock aquifers or where permeability is controlled by channelized fluvial deposits, lateral flow is not sufficiently developed to explain fast-developing gas contamination (0-3 months) or large length scales (∼1 km) documented in field studies. Thus, current efforts to evaluate the frequency, mechanism, and impacts of natural gas leakage from faulty natural gas wells likely underestimate contributions from small-volume, low-pressure leakage events. © 2018, National Ground Water Association.

  13. Comparison of Color Model in Cotton Image Under Conditions of Natural Light

    Science.gov (United States)

    Zhang, J. H.; Kong, F. T.; Wu, J. Z.; Wang, S. W.; Liu, J. J.; Zhao, P.

    Although the color images contain a large amount of information reflecting the species characteristics, different color models also get different information. The selection of color models is the key to separating crops from background effectively and rapidly. Taking the cotton images collected under natural light as the object, we convert the color components of RGB color model, HSL color model and YIQ color model respectively. Then, we use subjective evaluation and objective evaluation methods, evaluating the 9 color components of conversion. It is concluded that the Q component of the soil, straw and plastic film region gray values remain the same without larger fluctuation when using subjective evaluation method. In the objective evaluation, we use the variance method, average gradient method, gray prediction objective evaluation error statistics method and information entropy method respectively to find the minimum numerical of Q color component suitable for background segmentation.

  14. Cleaning up a salt spill : predictive modelling and monitoring natural attenuation to save remedial costs

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, B.; Shaikh, A.A. [EBA Engineering Consultants Ltd., Calgary, AB (Canada)

    2006-07-01

    Predictive modelling and monitoring natural attenuation to save remedial costs in cleaning up a salt spill were discussed with reference to a site located in central Alberta, as well as a pipeline break in 2002 from a corroded pipe which resulted in a large spill of produced water and oil. Remedial alternatives and an assessment of the site were presented. This included an electromagnetic survey in 2004, groundwater flow regime, soil and groundwater quality data, vegetation survey, and predictive modelling versus observed water quality. Photos and illustrations of the site from the air were provided. A conceptual salt leaching and transport model was proposed as a solution. Model calculation results were also presented. Last, the presentation discussed some important considerations for predictive modeling and next steps for the site. These included continued monitoring, implementation of a restoration plan and engagement of stakeholders such as Alberta Environment and the site landowner. tabs., figs.

  15. 3D animation model with augmented reality for natural science learning in elementary school

    Science.gov (United States)

    Hendajani, F.; Hakim, A.; Lusita, M. D.; Saputra, G. E.; Ramadhana, A. P.

    2018-05-01

    Many opinions from primary school students' on Natural Science are a difficult lesson. Many subjects are not easily understood by students, especially on materials that teach some theories about natural processes. Such as rain process, condensation and many other processes. The difficulty that students experience in understanding it is that students cannot imagine the things that have been taught in the material. Although there is material to practice some theories but is actually quite limited. There is also a video or simulation material in the form of 2D animated images. Understanding concepts in natural science lessons are also poorly understood by students. Natural Science learning media uses 3-dimensional animation models (3D) with augmented reality technology, which offers some visualization of science lessons. This application was created to visualize a process in Natural Science subject matter. The hope of making this application is to improve student's concept. This app is made to run on a personal computer that comes with a webcam with augmented reality. The app will display a 3D animation if the camera can recognize the marker.

  16. Priming of plant resistance by natural compounds. Hexanoic acid as a model

    Directory of Open Access Journals (Sweden)

    Paz eAranega Bou

    2014-10-01

    Full Text Available Some alternative control strategies of currently emerging plant diseases are based on the use of resistance inducers. This review highlights the recent advances made in the characterization of natural compounds that induce resistance by a priming mechanism. These include vitamins, chitosans, oligogalacturonides, volatile organic compounds, azelaic and pipecolic acid, among others. Overall, other than providing novel disease control strategies that meet environmental regulations, natural priming agents are valuable tools to help unravel the complex mechanisms underlying the induced resistance phenomenon. The data presented in this review reflect the novel contributions made from studying these natural plant inducers, with special emphasis placed on hexanoic acid (Hx, proposed herein as a model tool for this research field. Hx is a potent natural priming agent of proven efficiency in a wide range of host plants and pathogens. It can early activate broad-spectrum defenses by inducing callose deposition and the SA and JA pathways. Later it can prime pathogen-specific responses according to the pathogen’s lifestyle. Interestingly, Hx primes redox-related genes to produce an anti-oxidant protective effect, which might be critical for limiting the infection of necrotrophs. Our Hx-induced resistance (Hx-IR findings also strongly suggest that it is an attractive tool for the molecular characterization of the plant alarmed state, with the added advantage of it being a natural compound.

  17. Quantifying natural delta variability using a multiple-point geostatistics prior uncertainty model

    Science.gov (United States)

    Scheidt, Céline; Fernandes, Anjali M.; Paola, Chris; Caers, Jef

    2016-10-01

    We address the question of quantifying uncertainty associated with autogenic pattern variability in a channelized transport system by means of a modern geostatistical method. This question has considerable relevance for practical subsurface applications as well, particularly those related to uncertainty quantification relying on Bayesian approaches. Specifically, we show how the autogenic variability in a laboratory experiment can be represented and reproduced by a multiple-point geostatistical prior uncertainty model. The latter geostatistical method requires selection of a limited set of training images from which a possibly infinite set of geostatistical model realizations, mimicking the training image patterns, can be generated. To that end, we investigate two methods to determine how many training images and what training images should be provided to reproduce natural autogenic variability. The first method relies on distance-based clustering of overhead snapshots of the experiment; the second method relies on a rate of change quantification by means of a computer vision algorithm termed the demon algorithm. We show quantitatively that with either training image selection method, we can statistically reproduce the natural variability of the delta formed in the experiment. In addition, we study the nature of the patterns represented in the set of training images as a representation of the "eigenpatterns" of the natural system. The eigenpattern in the training image sets display patterns consistent with previous physical interpretations of the fundamental modes of this type of delta system: a highly channelized, incisional mode; a poorly channelized, depositional mode; and an intermediate mode between the two.

  18. A model of primate visual cortex based on category-specific redundancies in natural images

    Science.gov (United States)

    Malmir, Mohsen; Shiry Ghidary, S.

    2010-12-01

    Neurophysiological and computational studies have proposed that properties of natural images have a prominent role in shaping selectivity of neurons in the visual cortex. An important property of natural images that has been studied extensively is the inherent redundancy in these images. In this paper, the concept of category-specific redundancies is introduced to describe the complex pattern of dependencies between responses of linear filters to natural images. It is proposed that structural similarities between images of different object categories result in dependencies between responses of linear filters in different spatial scales. It is also proposed that the brain gradually removes these dependencies in different areas of the ventral visual hierarchy to provide a more efficient representation of its sensory input. The authors proposed a model to remove these redundancies and trained it with a set of natural images using general learning rules that are developed to remove dependencies between responses of neighbouring neurons. Results of experiments demonstrate the close resemblance of neuronal selectivity between different layers of the model and their corresponding visual areas.

  19. An investigation of implicit turbulence modeling for laminar-turbulent transition in natural convection

    Science.gov (United States)

    Li, Chunggang; Tsubokura, Makoto; Wang, Weihsiang

    2017-11-01

    The automatic dissipation adjustment (ADA) model based on truncated Navier-Stokes equations is utilized to investigate the feasibility of using implicit large eddy simulation (ILES) with ADA model on the transition in natural convection. Due to the high Rayleigh number coming from the larger temperature difference (300K), Roe scheme modified for low Mach numbers coordinating ADA model is used to resolve the complicated flow field. Based on the qualitative agreement of the comparisons with DNS and experimental results and the capability of numerically predicating a -3 decay law for the temporal power spectrum of the temperature fluctuation, this study thus validates the feasibility of ILES with ADA model on turbulent natural convection. With the advantages of ease of implementation because no explicit modeling terms are needed and nearly free of tuning parameters, ADA model offers to become a promising tool for turbulent thermal convection. Part of the results is obtained using the K computer at the RIKEN Advanced Institute for Computational Science (Proposal number hp160232).

  20. Assessment of MELCOR condensation models with the presence of noncondensable gas in natural convection flow regime

    International Nuclear Information System (INIS)

    Yoon, Dhongik S; Jo, HangJin; Corradini, Michael L

    2017-01-01

    Condensation of steam vapor is an important mode of energy removal from the reactor containment. The presence of noncondensable gas complicates the process and makes it difficult to model. MELCOR, one of the more widely used system codes for containment analyses, uses the heat and mass transfer analogy to model condensation heat transfer. To investigate previously reported nodalization-dependence in natural convection flow regime, MELCOR condensation model as well as other models are studied. The nodalization-dependence issue is resolved by using physical length from the actual geometry rather than node size of each control volume as the characteristic length scale for MELCOR containment analyses. At the transition to turbulent natural convection regime, the McAdams correlation for convective heat transfer produces a better prediction compared to the original MELCOR model. The McAdams correlation is implemented in MELCOR and the prediction is validated against a set of experiments on a scaled AP600 containment. The MELCOR with our implemented model produces improved predictions. For steam molar fractions in the gas mixture greater than about 0.58, the predictions are within the uncertainty margin of the measurements. The simulation results still underestimate the heat transfer from the gas-steam mixture, implying that conservative predictions are provided.

  1. Development of a butterfly check valve model under natural circulation conditions

    International Nuclear Information System (INIS)

    Rao, Yuxian; Yu, Lei; Fu, Shengwei; Zhang, Fan

    2015-01-01

    Highlights: • Bases on Lim’s swing check valve model, a butterfly check valve model was developed. • The method to quantify the friction torque T F in Li’s model was corrected. • The developed model was implemented into the RELAP5 code and verified. - Abstract: A butterfly check valve is widely used to prevent a reverse flow in the pipe lines of a marine nuclear power plant. Under some conditions, the natural circulation conditions in particular, the fluid velocity through the butterfly check valve might become too low to hold the valve disk fully open, thereby the flow resistance of the butterfly check valve varies with the location of the valve disk and as a result the fluid flow is significantly affected by the dynamic motion of the valve disk. Simulation of a pipe line that includes some butterfly check valves, especially under natural circulation conditions, is thus complicated. This paper focuses on the development of a butterfly check valve model to enhance the capability of the thermal–hydraulic system code and the developed model is implemented into the RELAP5 code. Both steady-state calculations and transient calculations were carried out for the primary loop system of a marine nuclear power plant and the calculation results are compared with the experimental data for verification purpose. The simulation results show an agreement with the experimental data

  2. Modelling and experimental studies on a mixed-mode natural convection solar crop-dryer

    Energy Technology Data Exchange (ETDEWEB)

    Forson, F.K. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Nazha, M.A.A.; Rajakaruna, H. [School of Engineering and Technology, De Montfort University, Queens Building, Leicester LE1 9BH (United Kingdom)

    2007-03-15

    A mathematical model for drying agricultural products in a mixed-mode natural convection solar crop dryer (MNCSCD) using a single-pass double-duct solar air-heater (SPDDSAH) is presented. The model was developed in parallel with experimental work. The model comprises the air-heating process model, the drying model and the technical performance criteria model. The governing equations of the drying air temperature and humidity ratio; the material temperature and its moisture content; and performance criteria indicators are derived. The model requires the solution of a number of interrelated non-linear equations and a set of simultaneous differential equations. Results from experimental studies used for generating the required experimental data for validating the model are presented. Results of simulation runs using the model are presented and compared with the experimental data. It is shown that the model can predict the performance of the MNCSCD fairly accurately and therefore can be used as a design tool for prototype development. (author)

  3. 2D Modeling of Flood Propagation due to the Failure of Way Ela Natural Dam

    Directory of Open Access Journals (Sweden)

    Yakti Bagus Pramono

    2018-01-01

    Full Text Available A dam break induced-flood propagation modeling is needed to reduce the losses of any potential dam failure. On the 25 July 2013, there was a dam break generated flood due to the failure of Way Ela Natural Dam that severely damaged houses and various public facilities. This study simulated the flooding induced by the failure of Way Ela Natural Dam. A two-dimensional (2D numerical model, HEC-RAS v.5, is used to simulate the overland flow. The dam failure itself is simulated using HECHMSv.4. The results of this study, the flood inundation, flood depth, and flood arrival time are verified by using available secondary data. These informations are very important to propose mitigation plans with respect to possible dam break in the future.

  4. The Employment of spatial autoregressive models in predicting demand for natural gas

    International Nuclear Information System (INIS)

    Castro, Jorge Henrique de; Silva, Alexandre Pinto Alves da

    2010-01-01

    Develop the natural gas network is critical success factor for the distribution company. It is a decision that employs the demand given location 'x' and a future time 't' so that the net allows the best conditions for the return of the capital. In this segment, typical network industry, the spatial infra-structure vision associated to the market allows better evaluation of the business because to mitigate costs and risks. In fact, economic models little developed in order to assess the question of the location, due to its little employment by economists. The objective of this article is to analyze the application of spatial perspective in natural gas demand forecasting and to identify the models that can be employed observing issues of dependency and spatial heterogeneity; as well as the capacity of mapping of variables associated with the problem. (author)

  5. Modeling a forced to natural convection boiling test with the program LOOP-W

    International Nuclear Information System (INIS)

    Carbajo, J.J.

    1984-01-01

    Extensive testing has been conducted in the Simulant Boiling Flow Visualization (SBFV) loop in which water is boiled in a vertical transparent tube by circulating hot glycerine in an annulus surrounding the tube. Tests ranged from nonboiling forced convection to oscillatory boiling natural convection. The program LOOP-W has been developed to analyze these tests. This program is a multi-leg, one-dimensional, two-phase equilibrium model with slip between the phases. In this study, a specific test, performed at low power where non-boiling forced convection was changed to boiling natural convection and then to non-boiling again, has been modeled with the program LOOP-W

  6. Climate change impacts utilizing regional models for agriculture, hydrology and natural ecosystems

    Science.gov (United States)

    Kafatos, M.; Asrar, G. R.; El-Askary, H. M.; Hatzopoulos, N.; Kim, J.; Kim, S.; Medvigy, D.; Prasad, A. K.; Smith, E.; Stack, D. H.; Tremback, C.; Walko, R. L.

    2012-12-01

    Climate change impacts the entire Earth but with crucial and often catastrophic impacts at local and regional levels. Extreme phenomena such as fires, dust storms, droughts and other natural hazards present immediate risks and challenges. Such phenomena will become more extreme as climate change and anthropogenic activities accelerate in the future. We describe a major project funded by NIFA (Grant # 2011-67004-30224), under the joint NSF-DOE-USDA Earth System Models (EaSM) program, to investigate the impacts of climate variability and change on the agricultural and natural (i.e. rangeland) ecosystems in the Southwest USA using a combination of historical and present observations together with climate, and ecosystem models, both in hind-cast and forecast modes. The applicability of the methodology to other regions is relevant (for similar geographic regions as well as other parts of the world with different agriculture and ecosystems) and should advance the state of knowledge for regional impacts of climate change. A combination of multi-model global climate projections from the decadal predictability simulations, to downscale dynamically these projections using three regional climate models, combined with remote sensing MODIS and other data, in order to obtain high-resolution climate data that can be used with hydrological and ecosystem models for impacts analysis, is described in this presentation. Such analysis is needed to assess the future risks and potential impacts of projected changes on these natural and managed ecosystems. The results from our analysis can be used by scientists to assist extended communities to determine agricultural coping strategies, and is, therefore, of interest to wide communities of stakeholders. In future work we will be including surface hydrologic modeling and water resources, extend modeling to higher resolutions and include significantly more crops and geographical regions with different weather and climate conditions

  7. Market chances for innovative natural gas applications. The determination of market potential by means of a phase model

    International Nuclear Information System (INIS)

    Hoelen, Q.E.J.J.M.; Klootwijk, M.

    2000-01-01

    Innovative applications of natural gas can increase the sale of natural gas, support energy companies in the development of commercial activities, and contribute to energy efficiency measures. The Dutch natural gas trading company Gasunie supports those developments by investigating the market potential of innovative gas appliances. Use is made of the so-called Phase Model for Market Introduction, developed by Kea Consult

  8. Watershed System Model: The Essentials to Model Complex Human-Nature System at the River Basin Scale

    Science.gov (United States)

    Li, Xin; Cheng, Guodong; Lin, Hui; Cai, Ximing; Fang, Miao; Ge, Yingchun; Hu, Xiaoli; Chen, Min; Li, Weiyue

    2018-03-01

    Watershed system models are urgently needed to understand complex watershed systems and to support integrated river basin management. Early watershed modeling efforts focused on the representation of hydrologic processes, while the next-generation watershed models should represent the coevolution of the water-land-air-plant-human nexus in a watershed and provide capability of decision-making support. We propose a new modeling framework and discuss the know-how approach to incorporate emerging knowledge into integrated models through data exchange interfaces. We argue that the modeling environment is a useful tool to enable effective model integration, as well as create domain-specific models of river basin systems. The grand challenges in developing next-generation watershed system models include but are not limited to providing an overarching framework for linking natural and social sciences, building a scientifically based decision support system, quantifying and controlling uncertainties, and taking advantage of new technologies and new findings in the various disciplines of watershed science. The eventual goal is to build transdisciplinary, scientifically sound, and scale-explicit watershed system models that are to be codesigned by multidisciplinary communities.

  9. Probabilistic disaggregation model with application to natural hazard risk assessment of portfolios

    OpenAIRE

    Custer, Rocco; Nishijima, Kazuyoshi

    2012-01-01

    In natural hazard risk assessment, a resolution mismatch between hazard data and aggregated exposure data is often observed. A possible solution to this issue is the disaggregation of exposure data to match the spatial resolution of hazard data. Disaggregation models available in literature are usually deterministic and make use of auxiliary indicator, such as land cover, to spatially distribute exposures. As the dependence between auxiliary indicator and disaggregated number of exposures is ...

  10. A simplified model of aerosol removal by natural processes in reactor containments

    Energy Technology Data Exchange (ETDEWEB)

    Powers, D.A.; Washington, K.E.; Sprung, J.L. [Sandia National Labs., Albuquerque, NM (United States); Burson, S.B. [Nuclear Regulatory Commission, Washington, DC (United States)

    1996-07-01

    Simplified formulae are developed for estimating the aerosol decontamination that can be achieved by natural processes in the containments of pressurized water reactors and in the drywells of boiling water reactors under severe accident conditions. These simplified formulae were derived by correlation of results of Monte Carlo uncertainty analyses of detailed models of aerosol behavior under accident conditions. Monte Carlo uncertainty analyses of decontamination by natural aerosol processes are reported for 1,000, 2,000, 3,000, and 4,000 MW(th) pressurized water reactors and for 1,500, 2,500, and 3,500 MW(th) boiling water reactors. Uncertainty distributions for the decontamination factors and decontamination coefficients as functions of time were developed in the Monte Carlo analyses by considering uncertainties in aerosol processes, material properties, reactor geometry and severe accident progression. Phenomenological uncertainties examined in this work included uncertainties in aerosol coagulation by gravitational collision, Brownian diffusion, turbulent diffusion and turbulent inertia. Uncertainties in aerosol deposition by gravitational settling, thermophoresis, diffusiophoresis, and turbulent diffusion were examined. Electrostatic charging of aerosol particles in severe accidents is discussed. Such charging could affect both the coagulation and deposition of aerosol particles. Electrostatic effects are not considered in most available models of aerosol behavior during severe accidents and cause uncertainties in predicted natural decontamination processes that could not be taken in to account in this work. Median (50%), 90 and 10% values of the uncertainty distributions for effective decontamination coefficients were correlated with time and reactor thermal power. These correlations constitute a simplified model that can be used to estimate the decontamination by natural aerosol processes at 3 levels of conservatism. Applications of the model are described.

  11. Focal species and landscape "naturalness" corridor models offer complementary approaches for connectivity conservation planning

    Science.gov (United States)

    Meade Krosby; Ian Breckheimer; D. John Pierce; Peter H. Singleton; Sonia A. Hall; Karl C. Halupka; William L. Gaines; Robert A. Long; Brad H. McRae; Brian L. Cosentino; Joanne P. Schuett-Hames

    2015-01-01

    Context   The dual threats of habitat fragmentation and climate change have led to a proliferation of approaches for connectivity conservation planning. Corridor analyses have traditionally taken a focal species approach, but the landscape ‘‘naturalness’’ approach of modeling connectivity among areas of low human modification has gained popularity...

  12. Computational Fluid Dynamics Modeling to Improve Natural Flow Rate and Sweet Pepper Productivity in Greenhouse

    OpenAIRE

    W. Limtrakarn; P. Boonmongkol; A. Chompupoung; K. Rungprateepthaworn; J. Kruenate; P. Dechaumphai

    2012-01-01

    Natural flow rate and sweet peppers productivity in tropical greenhouse are improved by CFD simulation is the main objective of this research work. Most of the greenhouse types today are in the arch shape. To develop an improved greenhouse structure for the region, the arch type was built and used as the control model. Mae Sar Mai agriculture research station under the royal project foundation was selected as the field test site. Temperature sensors with data logger were installed to monitor ...

  13. Neural Network Models of Regulating Natural Capital Funds for Renewable Energy

    OpenAIRE

    Alsayyed, Nidal; Zhu, Weihang

    2016-01-01

    Natural Capital (NC) is the limited form of capital assets or service (tangible or intangible) that satisfies basic and social conditions for human existence and protection The aim of this paper is twofold; First we examine and test empirically the conventional financing models and discuss their performance in regulating the financing structure of NC funds using a parametric estimating approach Generalized Moments Method (GMM). Second we estimate the NC dynamics using a nonparametric approach...

  14. Unified fluid flow model for pressure transient analysis in naturally fractured media

    International Nuclear Information System (INIS)

    Babak, Petro; Azaiez, Jalel

    2015-01-01

    Naturally fractured reservoirs present special challenges for flow modeling with regards to their internal geometrical structure. The shape and distribution of matrix porous blocks and the geometry of fractures play key roles in the formulation of transient interporosity flow models. Although these models have been formulated for several typical geometries of the fracture networks, they appeared to be very dissimilar for different shapes of matrix blocks, and their analysis presents many technical challenges. The aim of this paper is to derive and analyze a unified approach to transient interporosity flow models for slightly compressible fluids that can be used for any matrix geometry and fracture network. A unified fractional differential transient interporosity flow model is derived using asymptotic analysis for singularly perturbed problems with small parameters arising from the assumption of a much smaller permeability of the matrix blocks compared to that of the fractures. This methodology allowed us to unify existing transient interporosity flow models formulated for different shapes of matrix blocks including bounded matrix blocks, unbounded matrix cylinders with any orthogonal crossection, and matrix slabs. The model is formulated using a fractional order diffusion equation for fluid pressure that involves Caputo derivative of order 1/2 with respect to time. Analysis of the unified fractional derivative model revealed that the surface area-to-volume ratio is the key parameter in the description of the flow through naturally fractured media. Expressions of this parameter are presented for matrix blocks of the same geometrical shape as well as combinations of different shapes with constant and random sizes. Numerical comparisons between the predictions of the unified model and those obtained from existing transient interporosity ones for matrix blocks in the form of slabs, spheres and cylinders are presented for linear, radial and spherical flow types for

  15. Engaging Students with the Nature of Science and the Nature of Technology by Modeling the Work of Scientists

    Science.gov (United States)

    Kruse, Jerrid W.; Wilcox, Jesse L.

    2013-01-01

    Just as science education is too often limited to the acquisition of facts, technology education is too often limited to proficient use of technology. Neither of these goals fully realize a robust definition of science and technology literacy. To achieve greater science and technology literacy, students must understand the natures of both science…

  16. On the nature of the sea ice albedo feedback in simple models

    OpenAIRE

    Moon, Woosok; Wettlaufer, John S.

    2013-01-01

    We examine the nature of the ice-albedo feedback in a long standing approach used in the dynamic-thermodynamic modeling of sea ice. The central issue examined is how the evolution of the ice area is treated when modeling a partial ice cover using a two-category-thickness scheme; thin sea ice and open water in one category and "thick" sea ice in the second. The problem with the scheme is that the area-evolution is handled in a manner that violates the basic rules of calculus, which leads to a ...

  17. BSim Models for 2 Case-studies of Naturally and Mechanically Ventilated Daycare Institutions

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per

    and conclusions derived from the results of simulation of two different institutions in various operational modes. Thermal models are prepared for two buildings, which are: SFO Nymarken in Kerterminde and SFO Spirehuset in Hirtshals. The main operational principles in these buildings are significantly different......, as SFO Nymarken is mechanically ventilated and SFO Spirehuset is naturally ventilated. All of the simulations were carried in BSim, and all of the models are simulated in the current version of BSim, which is version 6,8,9,8....

  18. Preservice Biology Teachers' Conceptions About the Tentative Nature of Theories and Models in Biology

    Science.gov (United States)

    Reinisch, Bianca; Krüger, Dirk

    2018-02-01

    In research on the nature of science, there is a need to investigate the role and status of different scientific knowledge forms. Theories and models are two of the most important knowledge forms within biology and are the focus of this study. During interviews, preservice biology teachers ( N = 10) were asked about their understanding of theories and models. They were requested to give reasons why they see theories and models as either tentative or certain constructs. Their conceptions were then compared to philosophers' positions (e.g., Popper, Giere). A category system was developed from the qualitative content analysis of the interviews. These categories include 16 conceptions for theories ( n tentative = 11; n certai n = 5) and 18 conceptions for models ( n tentative = 10; n certain = 8). The analysis of the interviews showed that the preservice teachers gave reasons for the tentativeness or certainty of theories and models either due to their understanding of the terms or due to their understanding of the generation or evaluation of theories and models. Therefore, a variety of different terminology, from different sources, should be used in learning-teaching situations. Additionally, an understanding of which processes lead to the generation, evaluation, and refinement or rejection of theories and models should be discussed with preservice teachers. Within philosophy of science, there has been a shift from theories to models. This should be transferred to educational contexts by firstly highlighting the role of models and also their connections to theories.

  19. Validation of the natural resource damage assessment model using historical observations on oil spills

    International Nuclear Information System (INIS)

    French, D.; Rines, H.

    1995-01-01

    The Natural Resource Damage Assessment Model for Coastal and Marine Environments (NRDAM/CME) was developed by Applied Science Associates to simulate the fate and effects of oil and chemical spills into estuarine and marine environments. The US Department of the Interior has proposed the NRDAM/CME for use in Natural Resource Damage Assessment (NRDA) regulations under CERCLA. As part of the evaluation of model performance, the NRDAM/CME has been validated with observational data from case histories of oil spills, including the Exxon Valdez, World Prodigy, Mega Borg, Apex Houston and a number of others. Primarily, the data available for validation were of oil slick trajectory and coverage (e.g., overflight maps), length of shoreline oiled, area of marshes oiled, and a number of oiled birds recovered. Model performance was dependent on the accuracy of available wind and current data (the primary forces affecting fate) and bird abundances. Where these data sources were good (relatively well quantified), model performance was excellent. Results of the model simulations also provide an interesting sensitivity analysis and indications of relative effects of oil under various spill scenarios and conditions

  20. Modeling the intention to choose natural vaginal delivery: using reasoned action and social cognitive theories.

    Science.gov (United States)

    Kanani, Safieh; Allahverdipour, Hamid; AsghariJafarabadi, Mohammad

    2015-01-01

    The Behavioral Intention Model is one of the best and most widely models used regarding attitude of behavioral of pregnancy and decrease the rate of cesarean section (CS) among pregnant women, except effect of attitude and subjective norms on behavioral intention. Two variables of self-efficacy, and outcome expectation, relate to individual's behavior in an upcoming situation, and both of them are important at the development of behavior. The purpose of the present study was to develop a model to explain women's inten-tion to choose natural vaginal delivery (NVD). The variables of self-efficacy and outcome expectations, derived from Bandura's Social Cognitive Theory, and Behavioral Intention Model constructs were used to define the model. The study was descriptive and cross-sectional in nature and took place in Pars Abad, Iran in 2014. The non-probability sample consisted of 200 pregnant women who voluntarily participated in the study and provided the data. SPSS 21 and MPLUS 6.8 were employed to analyze the data. Self-efficacy, outcome expectations, and attitude toward NVD were associated with intention to choose the NVD. The study findings may play a role in designing educational interventions aimed at influencing the NVD and improving childbirth programs.

  1. Predictive Modelling of Concentration of Dispersed Natural Gas in a Single Room

    Directory of Open Access Journals (Sweden)

    Abdulfatai JIMOH

    2009-07-01

    Full Text Available This paper aimed at developing a mathematical model equation to predict the concentration of natural gas in a single room. The model equation was developed by using theoretical method of predictive modelling. The model equation developed is as given in equation 28. The validity of the developed expression was tested through the simulation of experimental results using computer software called MathCAD Professional. Both experimental and simulated results were found to be in close agreement. The statistical analysis carried out through the correlation coefficients for the results of experiment 1, 2, 3 and 4 were found to be 0.9986, 1.0000, 0.9981 and 0.9999 respectively, which imply reasonable close fittings between the experimental and simulated concentrations of dispersed natural gas within the room. Thus, the model equation developed can be considered a good representation of the phenomena that occurred when there is a leakage or accidental release of such gas within the room.

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

    Directory of Open Access Journals (Sweden)

    Rolando Barrera

    2014-01-01

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

  3. Probabilistic disaggregation model with application to natural hazard risk assessment of portfolios

    DEFF Research Database (Denmark)

    Custer, Rocco; Nishijima, Kazuyoshi

    In natural hazard risk assessment, a resolution mismatch between hazard data and aggregated exposure data is often observed. A possible solution to this issue is the disaggregation of exposure data to match the spatial resolution of hazard data. Disaggregation models available in literature...... disaggregation model that considers the uncertainty in the disaggregation, taking basis in the scaled Dirichlet distribution. The proposed probabilistic disaggregation model is applied to a portfolio of residential buildings in the Canton Bern, Switzerland, subject to flood risk. Thereby, the model is verified...... are usually deterministic and make use of auxiliary indicator, such as land cover, to spatially distribute exposures. As the dependence between auxiliary indicator and disaggregated number of exposures is generally imperfect, uncertainty arises in disaggregation. This paper therefore proposes a probabilistic...

  4. A Neural Parametric Singing Synthesizer Modeling Timbre and Expression from Natural Songs

    Directory of Open Access Journals (Sweden)

    Merlijn Blaauw

    2017-12-01

    Full Text Available We recently presented a new model for singing synthesis based on a modified version of the WaveNet architecture. Instead of modeling raw waveform, we model features produced by a parametric vocoder that separates the influence of pitch and timbre. This allows conveniently modifying pitch to match any target melody, facilitates training on more modest dataset sizes, and significantly reduces training and generation times. Nonetheless, compared to modeling waveform directly, ways of effectively handling higher-dimensional outputs, multiple feature streams and regularization become more important with our approach. In this work, we extend our proposed system to include additional components for predicting F0 and phonetic timings from a musical score with lyrics. These expression-related features are learned together with timbrical features from a single set of natural songs. We compare our method to existing statistical parametric, concatenative, and neural network-based approaches using quantitative metrics as well as listening tests.

  5. Electroweak chiral Lagrangian from a natural topcolor-assisted technicolor model

    International Nuclear Information System (INIS)

    Lang Junyi; Jiang Shaozhou; Wang Qing

    2009-01-01

    Based on previous studies on computing coefficients of the electroweak chiral Lagrangian from C. T. Hill's schematic topcolor-assisted technicolor model, we generalize the calculation to K. Lane's prototype natural topcolor-assisted technicolor model. We find that typical features of the model are qualitatively similar to those of Hill's, but Lane's model prefers a smaller technicolor group and the Z ' mass must be smaller than 400 GeV. Furthermore, the S parameter is around the order of +1, mainly due to the existence of three doublets of techniquarks. We obtain the values for all coefficients of the electroweak chiral Lagrangian up to the order p 4 . Apart from large negative four-fermion coupling values, the extended technicolor impacts on the electroweak chiral Lagrangian coefficients are small, since the techniquark self energy, which determines these coefficients, in general receives almost no influence from the extended technicolor induced four-fermion interactions except for its large momentum tail.

  6. Calibration of a gamma spectrometer for natural radioactivity measurement. Experimental measurements and Monte Carlo modelling

    International Nuclear Information System (INIS)

    Courtine, Fabien

    2007-03-01

    The thesis proceeded in the context of dating by thermoluminescence. This method requires laboratory measurements of the natural radioactivity. For that purpose, we have been using a germanium spectrometer. To refine the calibration of this one, we modelled it by using a Monte-Carlo computer code: Geant4. We developed a geometrical model which takes into account the presence of inactive zones and zones of poor charge-collection within the germanium crystal. The parameters of the model were adjusted by comparison with experimental results obtained with a source of 137 Cs. It appeared that the form of the inactive zones is less simple than is presented in the specialized literature. This model was widened to the case of a more complex source, with cascade effect and angular correlations between photons: the 60 Co. Lastly, applied to extended sources, it gave correct results and allowed us to validate the simulation of matrix effect. (author)

  7. Natural and Synthetic Biohydrogels Design, Characterization, Network Structure Imaging and Modeling

    Science.gov (United States)

    Marmorat, Clement

    Biocompatible hydrogels can be derived from materials that are naturally obtained, such as proteins or polysaccharides, or synthetic, such as poloxamers. In order to be classified as biocompatible, these water-swollen networks can not trigger a toxic response once introduced into a biological or physiological environment and, therefore, must be immunoneutral. Hyaluronic acid hydrogels can be great candidates for tissue engineering applications as long as the cross-linking chemistry and process does not affect the biocompatibility of the natural protein matrix. Thermoreversible hydrogels have the advantage of undergoing a sol/gel phase transition at specific temperatures. Thus, they are excellent candidates for biomedical applications such as drug delivery systems, wound healing coatings or cellular scaffolds. Although these hydrogels can be used in their natural form without further modification or chemical alteration, the original protein or polymer matrix is often strengthened by the use of a crosslinking agent to achieve a specific set of properties. In the case of gelatin fibril formation at low temperatures or the micellization of triblock copolymers in solution with temperature increase, the natural phase transition is modified when crosslinkers are introduced to alter the biohydrogels properties and, ultimately, disturb the system's equilibrium. By using spectroscopy techniques, rheology and cryo-imaging we investigated several biocompatible polymeric networks in their natural form as well as their engineered structures to better understand the mechanisms of gelation and artificial internal re-organization of the networks. Natural and synthetic biohydrogels were designed and their mechanical properties were characterized before imaging. Models that better describe the relationship between network configuration and resulting mechanical properties showed great agreement with experimental mesh size observations. Finally, a novel set of hybrid gels was developed

  8. Applying the natural disasters vulnerability evaluation model to the March 2011 north-east Japan earthquake and tsunami.

    Science.gov (United States)

    Ruiz Estrada, Mario Arturo; Yap, Su Fei; Park, Donghyun

    2014-07-01

    Natural hazards have a potentially large impact on economic growth, but measuring their economic impact is subject to a great deal of uncertainty. The central objective of this paper is to demonstrate a model--the natural disasters vulnerability evaluation (NDVE) model--that can be used to evaluate the impact of natural hazards on gross national product growth. The model is based on five basic indicators-natural hazards growth rates (αi), the national natural hazards vulnerability rate (ΩT), the natural disaster devastation magnitude rate (Π), the economic desgrowth rate (i.e. shrinkage of the economy) (δ), and the NHV surface. In addition, we apply the NDVE model to the north-east Japan earthquake and tsunami of March 2011 to evaluate its impact on the Japanese economy. © 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

  9. A Computational Fluid Dynamics Study of Turbulence, Radiation, and Combustion Models for Natural Gas Combustion Burner

    Directory of Open Access Journals (Sweden)

    Yik Siang Pang

    2018-01-01

    Full Text Available This paper presents a Computational Fluid Dynamics (CFD study of a natural gas combustion burner focusing on the effect of combustion, thermal radiation and turbulence models on the temperature and chemical species concentration fields. The combustion was modelled using the finite rate/eddy dissipation (FR/EDM and partially premixed flame models. Detailed chemistry kinetics CHEMKIN GRI-MECH 3.0 consisting of 325 reactions was employed to model the methane combustion. Discrete ordinates (DO and spherical harmonics (P1 model were employed to predict the thermal radiation. The gas absorption coefficient dependence on the wavelength is resolved by the weighted-sum-of-gray-gases model (WSGGM. Turbulence flow was simulated using Reynolds-averaged Navier-Stokes (RANS based models. The findings showed that a combination of partially premixed flame, P1 and standard k-ε (SKE gave the most accurate prediction with an average deviation of around 7.8% of combustion temperature and 15.5% for reactant composition (methane and oxygen. The results show the multi-step chemistry in the partially premixed model is more accurate than the two-step FR/EDM. Meanwhile, inclusion of thermal radiation has a minor effect on the heat transfer and species concentration. SKE turbulence model yielded better prediction compared to the realizable k-ε (RKE and renormalized k-ε (RNG. The CFD simulation presented in this work may serve as a useful tool to evaluate a performance of a natural gas combustor. Copyright © 2018 BCREC Group. All rights reserved Received: 26th July 2017; Revised: 9th October 2017; Accepted: 30th October 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Pang, Y.S., Law, W.P., Pung, K.Q., Gimbun, J. (2018. A Computational Fluid Dynamics Study of Turbulence, Radiation, and Combustion Models for Natural Gas Combustion Burner. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 155-169 (doi:10.9767/bcrec

  10. Can Geostatistical Models Represent Nature's Variability? An Analysis Using Flume Experiments

    Science.gov (United States)

    Scheidt, C.; Fernandes, A. M.; Paola, C.; Caers, J.

    2015-12-01

    The lack of understanding in the Earth's geological and physical processes governing sediment deposition render subsurface modeling subject to large uncertainty. Geostatistics is often used to model uncertainty because of its capability to stochastically generate spatially varying realizations of the subsurface. These methods can generate a range of realizations of a given pattern - but how representative are these of the full natural variability? And how can we identify the minimum set of images that represent this natural variability? Here we use this minimum set to define the geostatistical prior model: a set of training images that represent the range of patterns generated by autogenic variability in the sedimentary environment under study. The proper definition of the prior model is essential in capturing the variability of the depositional patterns. This work starts with a set of overhead images from an experimental basin that showed ongoing autogenic variability. We use the images to analyze the essential characteristics of this suite of patterns. In particular, our goal is to define a prior model (a minimal set of selected training images) such that geostatistical algorithms, when applied to this set, can reproduce the full measured variability. A necessary prerequisite is to define a measure of variability. In this study, we measure variability using a dissimilarity distance between the images. The distance indicates whether two snapshots contain similar depositional patterns. To reproduce the variability in the images, we apply an MPS algorithm to the set of selected snapshots of the sedimentary basin that serve as training images. The training images are chosen from among the initial set by using the distance measure to ensure that only dissimilar images are chosen. Preliminary investigations show that MPS can reproduce fairly accurately the natural variability of the experimental depositional system. Furthermore, the selected training images provide

  11. Evaluation of the Predictive Capabilities of a Phenomenological Combustion Model for Natural Gas SI Engine

    Directory of Open Access Journals (Sweden)

    Toman Rastislav

    2017-12-01

    Full Text Available The current study evaluates the predictive capabilities of a new phenomenological combustion model, available as a part of the GT-Suite software package. It is comprised of two main sub-models: 0D model of in-cylinder flow and turbulence, and turbulent SI combustion model. The 0D in-cylinder flow model (EngCylFlow uses a combined K-k-ε kinetic energy cascade approach to predict the evolution of the in-cylinder charge motion and turbulence, where K and k are the mean and turbulent kinetic energies, and ε is the turbulent dissipation rate. The subsequent turbulent combustion model (EngCylCombSITurb gives the in-cylinder burn rate; based on the calculation of flame speeds and flame kernel development. This phenomenological approach reduces significantly the overall computational effort compared to the 3D-CFD, thus allowing the computation of full engine operating map and the vehicle driving cycles. Model was calibrated using a full map measurement from a turbocharged natural gas SI engine, with swirl intake ports. Sensitivity studies on different calibration methods, and laminar flame speed sub-models were conducted. Validation process for both the calibration and sensitivity studies was concerning the in-cylinder pressure traces and burn rates for several engine operation points achieving good overall results.

  12. Bringing Chatbots into education: Towards Natural Language Negotiation of Open Learner Models

    Science.gov (United States)

    Kerlyl, Alice; Hall, Phil; Bull, Susan

    There is an extensive body of work on Intelligent Tutoring Systems: computer environments for education, teaching and training that adapt to the needs of the individual learner. Work on personalisation and adaptivity has included research into allowing the student user to enhance the system's adaptivity by improving the accuracy of the underlying learner model. Open Learner Modelling, where the system's model of the user's knowledge is revealed to the user, has been proposed to support student reflection on their learning. Increased accuracy of the learner model can be obtained by the student and system jointly negotiating the learner model. We present the initial investigations into a system to allow people to negotiate the model of their understanding of a topic in natural language. This paper discusses the development and capabilities of both conversational agents (or chatbots) and Intelligent Tutoring Systems, in particular Open Learner Modelling. We describe a Wizard-of-Oz experiment to investigate the feasibility of using a chatbot to support negotiation, and conclude that a fusion of the two fields can lead to developing negotiation techniques for chatbots and the enhancement of the Open Learner Model. This technology, if successful, could have widespread application in schools, universities and other training scenarios.

  13. Constraining Methane Emissions from Natural Gas Production in Northeastern Pennsylvania Using Aircraft Observations and Mesoscale Modeling

    Science.gov (United States)

    Barkley, Z.; Davis, K.; Lauvaux, T.; Miles, N.; Richardson, S.; Martins, D. K.; Deng, A.; Cao, Y.; Sweeney, C.; Karion, A.; Smith, M. L.; Kort, E. A.; Schwietzke, S.

    2015-12-01

    Leaks in natural gas infrastructure release methane (CH4), a potent greenhouse gas, into the atmosphere. The estimated fugitive emission rate associated with the production phase varies greatly between studies, hindering our understanding of the natural gas energy efficiency. This study presents a new application of inverse methodology for estimating regional fugitive emission rates from natural gas production. Methane observations across the Marcellus region in northeastern Pennsylvania were obtained during a three week flight campaign in May 2015 performed by a team from the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Division and the University of Michigan. In addition to these data, CH4 observations were obtained from automobile campaigns during various periods from 2013-2015. An inventory of CH4 emissions was then created for various sources in Pennsylvania, including coalmines, enteric fermentation, industry, waste management, and unconventional and conventional wells. As a first-guess emission rate for natural gas activity, a leakage rate equal to 2% of the natural gas production was emitted at the locations of unconventional wells across PA. These emission rates were coupled to the Weather Research and Forecasting model with the chemistry module (WRF-Chem) and atmospheric CH4 concentration fields at 1km resolution were generated. Projected atmospheric enhancements from WRF-Chem were compared to observations, and the emission rate from unconventional wells was adjusted to minimize errors between observations and simulation. We show that the modeled CH4 plume structures match observed plumes downwind of unconventional wells, providing confidence in the methodology. In all cases, the fugitive emission rate was found to be lower than our first guess. In this initial emission configuration, each well has been assigned the same fugitive emission rate, which can potentially impair our ability to match the observed spatial variability

  14. Annual individual hygienic assessment of natural exposure doses of the Altai territory model areas population

    Directory of Open Access Journals (Sweden)

    N. Yu. Potseluev

    2016-01-01

    Full Text Available The goal is to determine ionizing radiation natural sources exposure regularities of Altai Territory model areas population. The materials and methods. 11376 radon measurements, 1247 gamma radiation meas-urements in an open area and in residential and office buildings were performed, selection of 189 drinking water tests was carried out. Results. Complex radiation and hygienic examination of the region with the most large municipalities number with model areas allocation was conducted. The assessment of the Altai Territory population’s individual annual radiation doses from natural radionuclides has revealed a number of the regularities depending on the terrain’s ecological and geographical type. Following the research results, ranging the region territories taking into account of annual effective doses of the population from natural sources for 2009-2015 was carried out. The annual individual effective dose of the Altai Territory upland areas population presented by the highest values and ranges from 7.36 mSv / year to 8.19 mSv / year. Foothill regions of Altai and in Salair ridge are characterized by increased population exposure from natural sources. Here the dose ranges from 5.09 mSv / year to 6.22 mSv / year. Steppe and forest-steppe territories are characterized by the lowest level of the natural radiation which is ranging from 3.23 mSv / year to 4.11 mSv / year, that doesn’t exceed the all-Russian levels. Most of the hygienic radon equivalent equilibrium volume activity standards exceedances were registered in mountain and foothill areas buildings. A number of radon anomalies is revealed also in steppe areas. Med exceedances ranged from 203 ± 17.8 Bq / m3 to 480 ± 37.9 Bq / m3. Given the fact that most of these buildings belong to the administrative or educational institutions with an eight-hour working day, the dose of radiation for people there can be up to 10 mSv / year. Conclusion. Spreading of individual annual effective

  15. A review of modelling the interaction between natural organic matter and metal cations

    International Nuclear Information System (INIS)

    Falck, W.E.

    1989-01-01

    This report reviews techniques available to model the interaction between natural organic matter (mainly fulvic and humic acids) and protons and metal cations. A concise definition of natural organic matter is given and their properties are outlined. These materials are macromolecules which exhibit a polyelectrolyte character owing to numerous dissociable functional groups which are attached to their carbon backbone or from integral parts of the structure. The polyelectrolyte character is thought to be responsible for their conformation, hydrogen bonding or bridging by metal cations between subunits being important mechanisms. Environmental parameters like pH and ionic strength thus will have profound effects on the conformation of natural organic matter, the properties of which can change from being a flexible polymer to being a rigid gel. Binding mechanisms and binding strengh are discussed and an overview of relevant techniques of investigation is given. This work is part of the Commission's Mirage project - Phase 2, research area Geochemistry of actinides and fission products in natural aquifer systems

  16. Nature of science in instruction materials of science through the model of educational reconstruction

    Science.gov (United States)

    Azizah, Nur; Mudzakir, Ahmad

    2016-02-01

    The study was carried out to reconstruct the science teaching materials charged view of the nature of science (VNOS). This reconstruction process using the Model of Educational Reconstruction (MER), which is the framework for research and development of science education as well as a guide for planning the teaching of science in the schools is limited in two stages, namely: content structure analysis, and empirical studies of learners. The purpose of this study is to obtain a pre-conception of learners and prospective scientists to the topic of the nature of the material and utilization. The method used to descriptive with the instruments is guidelines for interviews for 15 students of class VIII, text analysis sheet, sheet analysis of the concept, and the validation sheet indicators and learning objectives NOS charged on cognitive and affective aspects. The results obtained in the form of pre-conceptions of learners who demonstrate almost 100% of students know the types of materials and some of its nature, the results of the scientist's perspective on the topic of the nature of the material and its use, as well as the results of the validation indicators and learning objectives charged NOS and competencies PISA 2015 cognitive and affective aspects with CVI value of 0.99 and 1.0 after being validated by five experts. This suggests that the indicators and the resulting learning objectives feasible and can proceed to the reconstruction of teaching materials on the topic of material properties and utilization.

  17. Integrated Modeling of the Human-Natural System to Improve Local Water Management and Planning

    Science.gov (United States)

    Gutowski, W. J., Jr.; Dziubanski, D.; Franz, K.; Goodwin, J.; Rehmann, C. R.; Simpkins, W. W.; Tesfastion, L.; Wanamaker, A. D.; Jie, Y.

    2015-12-01

    Communities across the world are experiencing the effects of unsustainable water management practices. Whether the problem is a lack of water, too much water, or water of degraded quality, finding acceptable solutions requires community-level efforts that integrate sound science with local needs and values. Our project develops both a software technology (agent-based hydrological modeling) and a social technology (a participatory approach to model development) that will allow communities to comprehensively address local water challenges. Using agent-based modeling (ABM), we are building a modeling system that includes a semi-distributed hydrologic process model coupled with agent (stakeholder) models. Information from the hydrologic model is conveyed to the agent models, which, along with economic information, determine appropriate agent actions that subsequently affect hydrology within the model. The iterative participatory modeling (IPM) process will assist with the continual development of the agent models. Further, IPM creates a learning environment in which all participants, including researchers, are co-exploring relevant data, possible scenarios and solutions, and viewpoints through continuous interactions. Our initial work focuses on the impact of flood mitigation and conservation efforts on reducing flooding in an urban area. We are applying all research elements above to the Squaw Creek watershed that flows through parts of four counties in central Iowa. The watershed offers many of the typical tensions encountered in Iowa, such as different perspectives on water management between upstream farmers and downstream urban areas, competition for various types of recreational services, and increasing absentee land ownership that may conflict with community values. Ultimately, climate change scenarios will be incorporated into the model to determine long term patterns that may develop within the social or natural system.

  18. Modeling study of the natural state of the Heber geothermal field, California

    Energy Technology Data Exchange (ETDEWEB)

    Lippmann, M.J.; Bodvarsson, G.S.

    1983-06-01

    As a first step in simulating the behavior of the Heber field under exploitation, the system is modeled in its natural (pre-exploitation) state. Using Lawrence Berkeley Laboratory's (LBL) computer code PT and a radially symmetric model, a reasonable match between published and calculated temperature and pressure distributions is obtained. The results of the study indicate that the Heber geothermal system is created by the upflow of hot water through a central zone of higher permeability. The model shows that in its natural state the system is recharged at depth by a 15 MW(thermal) convective heat source. The existence of a radially symmetric convection pattern, whose axis coincides with that of the Heber anomaly is suggested. At the lower part of the ascending hot water plume, the deep recharge water mixes with colder water moving laterally towards the axis of the system. On the upper part, the rising plume spreads radially outward before reaching the bottom of the caprock, at 550 m depth. The model results suggest that the caprock is quite permeable, with convection controlling the temperature distribution. The low permeability of the upper zones in the outer region of the system may be due to mineral precipitation.

  19. Technosocial Modeling for Determining the Status and Nature of a State’s Nuclear Activities

    Energy Technology Data Exchange (ETDEWEB)

    Gastelum, Zoe N.; Harvey, Julia B.

    2009-09-25

    The International Atomic Energy Agency State Evaluation Process: The Role of Information Analysis in Reaching Safeguards Conclusions (Mathews et al. 2008), several examples of nonproliferation models using analytical software were developed that may assist the IAEA with collecting, visualizing, analyzing, and reporting information in support of the State Evaluation Process. This paper focuses on one of the examples a set of models developed in the Proactive Scenario Production, Evidence Collection, and Testing (ProSPECT) software that evaluates the status and nature of a state’s nuclear activities. The models use three distinct subject areas to perform this assessment: the presence of nuclear activities, the consistency of those nuclear activities with national nuclear energy goals, and the geopolitical context in which those nuclear activities are taking place. As a proof-of-concept for the models, a crude case study was performed. The study, which attempted to evaluate the nuclear activities taking place in Syria prior to September 2007, yielded illustrative, yet inconclusive, results. Due to the inconclusive nature of the case study results, changes that may improve the model’s efficiency and accuracy are proposed.

  20. Modelling Individual Evacuation Decisions during Natural Disasters: A Case Study of Volcanic Crisis in Merapi, Indonesia

    Directory of Open Access Journals (Sweden)

    Jumadi

    2018-05-01

    Full Text Available As the size of human populations increases, so does the severity of the impacts of natural disasters. This is partly because more people are now occupying areas which are susceptible to hazardous natural events, hence, evacuation is needed when such events occur. Evacuation can be the most important action to minimise the impact of any disaster, but in many cases there are always people who are reluctant to leave. This paper describes an agent-based model (ABM of evacuation decisions, focusing on the emergence of reluctant people in times of crisis and using Merapi, Indonesia as a case study. The individual evacuation decision model is influenced by several factors formulated from a literature review and survey. We categorised the factors influencing evacuation decisions into two opposing forces, namely, the driving factors to leave (evacuate versus those to stay, to formulate the model. The evacuation decision (to stay/leave of an agent is based on an evaluation of the strength of these driving factors using threshold-based rules. This ABM was utilised with a synthetic population from census microdata, in which everyone is characterised by the decision rule. Three scenarios with varying parameters are examined to calibrate the model. Validations were conducted using a retrodictive approach by performing spatial and temporal comparisons between the outputs of simulation and the real data. We present the results of the simulations and discuss the outcomes to conclude with the most plausible scenario.

  1. A coupled hydrodynamic-hydrochemical modeling for predicting mineral transport in a natural acid drainage system.

    Science.gov (United States)

    Zegers Risopatron, G., Sr.; Navarro, L.; Montserrat, S., Sr.; McPhee, J. P.; Niño, Y.

    2017-12-01

    The geochemistry of water and sediments, coupled with hydrodynamic transport in mountainous channels, is of particular interest in central Chilean Andes due to natural occurrence of acid waters. In this paper, we present a coupled transport and geochemical model to estimate and understand transport processes and fate of minerals at the Yerba Loca Basin, located near Santiago, Chile. In the upper zone, water presentes low pH ( 3) and high concentrations of iron, aluminum, copper, manganese and zinc. Acidity and minerals are the consequence of water-rock interactions in hydrothermal alteration zones, rich in sulphides and sulphates, covered by seasonal snow and glaciers. Downstream, as a consequence of neutral to alkaline lateral water contributions (pH >7) along the river, pH increases and concentration of solutes decreases. The mineral transport model has three components: (i) a hydrodynamic model, where we use HEC-RAS to solve 1D Saint-Venant equations, (ii) a sediment transport model to estimate erosion and sedimentation rates, which quantify minerals transference between water and riverbed and (iii) a solute transport model, based on the 1D OTIS model which takes into account the temporal delay in solutes transport that typically is observed in natural channels (transient storage). Hydrochemistry is solved using PHREEQC, a software for speciation and batch reaction. Our results show that correlation between mineral precipitation and dissolution according to pH values changes along the river. Based on pH measurements (and according to literature) we inferred that main minerals in the water system are brochantite, ferrihydrite, hydrobasaluminite and schwertmannite. Results show that our model can predict the transport and fate of minerals and metals in the Yerba Loca Basin. Mineral dissolution and precipitation process occur for limited ranges of pH values. When pH values are increased, iron minerals (schwertmannite) are the first to precipitate ( 2.5

  2. A Test of the Optimality Approach to Modelling Canopy gas Exchange by Natural Vegetation

    Science.gov (United States)

    Schymanski, S. J.; Sivapalan, M.; Roderick, M. L.; Beringer, J.; Hutley, L. B.

    2005-12-01

    Natural vegetation has co-evolved with its environment over a long period of time and natural selection has led to a species composition that is most suited for the given conditions. Part of this adaptation is the vegetation's water use strategy, which determines the amount and timing of water extraction from the soil. Knowing that water extraction by vegetation often accounts for over 90% of the annual water balance in some places, we need to understand its controls if we want to properly model the hydrologic cycle. Water extraction by roots is driven by transpiration from the canopy, which in turn is an inevitable consequence of CO2 uptake for photosynthesis. Photosynthesis provides plants with their main building material, carbohydrates, and with the energy necessary to thrive and prosper in their environment. Therefore we expect that natural vegetation would have evolved an optimal water use strategy to maximise its `net carbon profit' (the difference between carbon acquired by photosynthesis and carbon spent on maintenance of the organs involved in its uptake). Based on this hypothesis and on an ecophysiological gas exchange and photosynthesis model (Cowan and Farquhar 1977; von Caemmerer 2000), we model the optimal vegetation for a site in Howard Springs (N.T., Australia) and compare the modelled fluxes with measurements by Beringer, Hutley et al. (2003). The comparison gives insights into theoretical and real controls on transpiration and photosynthesis and tests the optimality approach to modelling gas exchange of natural vegetation with unknown properties. The main advantage of the optimality approach is that no assumptions about the particular vegetation on a site are needed, which makes it very powerful for predicting vegetation response to long-term climate- or land use change. Literature: Beringer, J., L. B. Hutley, et al. (2003). "Fire impacts on surface heat, moisture and carbon fluxes from a tropical savanna in northern Australia." International

  3. Natural and sexual selection giveth and taketh away reproductive barriers: models of population divergence in guppies.

    Science.gov (United States)

    Labonne, Jacques; Hendry, Andrew P

    2010-07-01

    The standard predictions of ecological speciation might be nuanced by the interaction between natural and sexual selection. We investigated this hypothesis with an individual-based model tailored to the biology of guppies (Poecilia reticulata). We specifically modeled the situation where a high-predation population below a waterfall colonizes a low-predation population above a waterfall. Focusing on the evolution of male color, we confirm that divergent selection causes the appreciable evolution of male color within 20 generations. The rate and magnitude of this divergence were reduced when dispersal rates were high and when female choice did not differ between environments. Adaptive divergence was always coupled to the evolution of two reproductive barriers: viability selection against immigrants and hybrids. Different types of sexual selection, however, led to contrasting results for another potential reproductive barrier: mating success of immigrants. In some cases, the effects of natural and sexual selection offset each other, leading to no overall reproductive isolation despite strong adaptive divergence. Sexual selection acting through female choice can thus strongly modify the effects of divergent natural selection and thereby alter the standard predictions of ecological speciation. We also found that under no circumstances did divergent selection cause appreciable divergence in neutral genetic markers.

  4. Investigating the adaptive model of thermal comfort for naturally ventilated school buildings in Taiwan

    Science.gov (United States)

    Hwang, Ruey-Lung; Lin, Tzu-Ping; Chen, Chen-Peng; Kuo, Nai-Jung

    2009-03-01

    Divergence in the acceptability to people in different regions of naturally ventilated thermal environments raises a concern over the extent to which the ASHRAE Standard 55 may be applied as a universal criterion of thermal comfort. In this study, the ASHRAE 55 adaptive model of thermal comfort was investigated for its applicability to a hot and humid climate through a long-term field survey performed in central Taiwan among local students attending 14 elementary and high schools during September to January. Adaptive behaviors, thermal neutrality, and thermal comfort zones are explored. A probit analysis of thermal acceptability responses from students was performed in place of the conventional linear regression of thermal sensation votes against operative temperature to investigate the limits of comfort zones for 90% and 80% acceptability; the corresponding comfort zones were found to occur at 20.1-28.4°C and 17.6-30.0°C, respectively. In comparison with the yearly comfort zones recommended by the adaptive model for naturally ventilated spaces in the ASHRAE Standard 55, those observed in this study differ in the lower limit for 80% acceptability, with the observed level being 1.7°C lower than the ASHRAE-recommended value. These findings can be generalized to the population of school children, thus providing information that can supplement ASHRAE Standard 55 in evaluating the thermal performance of naturally ventilated school buildings, particularly in hot-humid areas such as Taiwan.

  5. Evaluating Engagement Models for a Citizen Science Project: Lessons Learned From Four Years of Nature's Notebook

    Science.gov (United States)

    Crimmins, T. M.; Rosemartin, A.

    2012-12-01

    The success of citizen science programs hinges on their abilities to recruit and maintain active participants. The USA National Phenology Network's plant and animal phenology observation program, Nature's Notebook, has been active since 2009. This program engages thousands of citizen scientists in tracking plant and animal life cycle activity over the course of the year. We embarked on an evaluation of the various observer recruitment and retention tactics that we have employed over the ~4-year life of this program to better inform future outreach efforts specific to Nature's Notebook and for the broader citizen science community. Participants in Nature's Notebook may become engaged via one of three pathways: individuals may join Nature's Notebook directly, they may be invited to join through a USA-NPN partner organization, or they may engage through a group with local, site-based leadership. The level and type of recruitment tactics, training, and retention efforts that are employed varies markedly among these three models. In this evaluation, we compared the efficacy of these three engagement models using several metrics: number of individuals recruited, number of individuals that go on to submit at least one data point, retention rates over time, duration of activity, and quantity of data points submitted. We also qualitatively considered the differences in costs the three models require to support. In terms of recruitment, direct engagement yielded 20-100 times more registrants than other two models. In contrast, rates of participation were highest for site-based leadership (>35%, versus 20-30% for direct engagement; rates for partner organizations were highly variable due to small sample sizes). Individuals participating through partners with site-based leadership showed a much higher rate of retention (41% of participants remained active for two+ years) than those participating directly in Nature's Notebook (27% of participants remained active for two+ years

  6. Transference and natural gas distribution system analysis utilizing hybrid modelling; Analise de sistemas de transferencia e distribuicao de gas natural utilizando modelagem hibrida

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Robson A.; Martinkoski, Ricardo [Centro Federal de Educacao Tecnologica do Parana (CEFET), Curitiba, PR (Brazil); Neves Junior, Flavio [Centro Federal de Educacao Tecnologica do Parana (CEFET), Curitiba, PR (Brazil). Programa de Pos-Graduacao em Engenharia Eletrica e Informatica Industrial

    2003-07-01

    The objective of this article is to apply techniques of formal specification in modelling of natural gas transmission and distribution systems. In this case the formal models are characterized by using hybrid automata. Initially the existent components in the net are modeled and represented by independent hybrid automata. The global dynamics is obtained through the product hybrid automata. Languages representing the desirable states of the system are obtained from the hybrid automata, allowing a hybrid control procedure. An automatic tool as SHIFT must be used to modelling and simulation. (author)

  7. Calculation models for prediction of Liquefied Natural Gas (LNG) ageing during ship transportation

    Energy Technology Data Exchange (ETDEWEB)

    Miana, Mario; Hoyo, Rafael del; Rodrigalvarez, Vega; Valdes, Jose Ramon [Instituto Tecnologico de Aragon, Area de Investigacion, Desarrollo y Servicios Tecnologicos, Maria de Luna 7, 50018 Zaragoza (Spain); Llorens, Raul [ENAGAS SA, Direccion de Ingenieria y Tecnologia del Gas, Autovia A - 2, km. 306.4, 50012 Zaragoza (Spain)

    2010-05-15

    A group of European gas transportation companies within the European Gas Research Group launched in 2007 the 'MOLAS' Project to provide a software program for the analysis of the Liquefied Natural Gas (LNG) ageing process during ship transportation. This program contains two different modeling approaches: a physical algorithm and an 'intelligent' model. Both models are fed with the same input data, which is composed of the ship characteristics (BOR and capacity), voyage duration, LNG composition, temperature, pressure, and volume occupied by liquid phase at the port of origin, together with pressure at the port of destination. The results obtained are the LNG composition, temperature and liquid volume at the port of destination. Furthermore, the physical model obtains the evolution over time of such variables en route as it is based on unsteady mass balances over the system, while the i-model applies neural networks to obtain regression coefficients from historical data composed only of origin and destination measurements. This paper describes both models and validates them from previous published models and experimental data measured in ENAGAS LNG regasification plants. (author)

  8. Computational Fluid Dynamics Modeling to Improve Natural Flow Rate and Sweet Pepper Productivity in Greenhouse

    Directory of Open Access Journals (Sweden)

    W. Limtrakarn

    2012-01-01

    Full Text Available Natural flow rate and sweet peppers productivity in tropical greenhouse are improved by CFD simulation is the main objective of this research work. Most of the greenhouse types today are in the arch shape. To develop an improved greenhouse structure for the region, the arch type was built and used as the control model. Mae Sar Mai agriculture research station under the royal project foundation was selected as the field test site. Temperature sensors with data logger were installed to monitor variation of temperature inside the greenhouse. The measured temperature data were used as the boundary conditions for the CFD analysis. A new greenhouse model with two-step roof shape was designed and the air flow behavior was simulated by using CFD. Regarding CFD results the air flow rate of the new model is about 39% higher than that of old model. The maximum temperature of the new model is lower than that of the old one. The sweet paper growths in both greenhouse models were measured and compared. Results show that the new model obtains 4°C lower maximum temperature in day time, 97% in number and 90% in weight higher the first grade pepper productivity than the old one.

  9. Conformists and contrarians in a Kuramoto model with identical natural frequencies

    Science.gov (United States)

    Hong, Hyunsuk; Strogatz, Steven H.

    2011-10-01

    We consider a variant of the Kuramoto model in which all the oscillators are now assumed to have the same natural frequency, but some of them are negatively coupled to the mean field. These contrarian oscillators tend to align in antiphase with the mean field, whereas, the positively coupled conformist oscillators favor an in-phase relationship. The interplay between these effects can lead to rich dynamics. In addition to a splitting of the population into two diametrically opposed factions, the system can also display traveling waves, complete incoherence, and a blurred version of the two-faction state. Exact solutions for these states and their bifurcations are obtained by means of the Watanabe-Strogatz transformation and the Ott-Antonsen ansatz. Curiously, this system of oscillators with identical frequencies turns out to exhibit more complicated dynamics than its counterpart with heterogeneous natural frequencies.

  10. Explaining the Timing of Natural Scene Understanding with a Computational Model of Perceptual Categorization

    Science.gov (United States)

    Sofer, Imri; Crouzet, Sébastien M.; Serre, Thomas

    2015-01-01

    Observers can rapidly perform a variety of visual tasks such as categorizing a scene as open, as outdoor, or as a beach. Although we know that different tasks are typically associated with systematic differences in behavioral responses, to date, little is known about the underlying mechanisms. Here, we implemented a single integrated paradigm that links perceptual processes with categorization processes. Using a large image database of natural scenes, we trained machine-learning classifiers to derive quantitative measures of task-specific perceptual discriminability based on the distance between individual images and different categorization boundaries. We showed that the resulting discriminability measure accurately predicts variations in behavioral responses across categorization tasks and stimulus sets. We further used the model to design an experiment, which challenged previous interpretations of the so-called “superordinate advantage.” Overall, our study suggests that observed differences in behavioral responses across rapid categorization tasks reflect natural variations in perceptual discriminability. PMID:26335683

  11. On a Formalization of Cantor Set Theory for Natural Models of the Physical Phenomena

    Directory of Open Access Journals (Sweden)

    Nudel'man A. S.

    2010-01-01

    Full Text Available This article presents a set theory which is an extension of ZFC . In contrast to ZFC , a new theory admits absolutely non-denumerable sets. It is feasible that a symbiosis of the proposed theory and Vdovin set theory will permit to formulate a (presumably non- contradictory axiomatic set theory which will represent the core of Cantor set theory in a maximally full manner as to the essence and the contents of the latter. This is possible due to the fact that the generalized principle of choice and the generalized continuum hypothesis are proved in Vdovin theory. The theory, being more complete than ZF and more natural according to Cantor, will allow to construct and study (in its framework only natural models of the real physical phenomena.

  12. On a Formalization of Cantor Set Theory for Natural Models of the Physical Phenomena

    Directory of Open Access Journals (Sweden)

    Nudel'man A. S.

    2010-01-01

    Full Text Available This article presents a set theory which is an extension of $ZFC$. In contrast to $ZFC$, a new theory admits absolutely non-denumerable sets. It is feasible that a symbiosis of the proposed theory and Vdovin set theory will permit to formulate a (presumably non-contradictory axiomatic set theory which will represent the core of Cantor set theory in a maximally full manner as to the essence and the contents of the latter. This is possible due to the fact that the generalized principle of choice and the generalized continuum hypothesis are proved in Vdovin theory. The theory, being more complete than $ZF$ and more natural according to Cantor, will allow to construct and study (in its framework only natural models of the real physical phenomena.

  13. A tale of twin Higgs: natural twin two Higgs doublet models

    International Nuclear Information System (INIS)

    Yu, Jiang-Hao

    2016-01-01

    In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit ℤ 2 breaking term. Introducing additional twin Higgs could accommodate spontaneous ℤ 2 breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and ℤ 2 symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit ℤ 2 breaking, radiative ℤ 2 breaking, tadpole-induced ℤ 2 breaking, and quartic-induced ℤ 2 breaking. We investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.

  14. Semi-analytical models of hydroelastic sloshing impact in tanks of liquefied natural gas vessels.

    Science.gov (United States)

    Ten, I; Malenica, Š; Korobkin, A

    2011-07-28

    The present paper deals with the methods for the evaluation of the hydroelastic interactions that appear during the violent sloshing impacts inside the tanks of liquefied natural gas carriers. The complexity of both the fluid flow and the structural behaviour (containment system and ship structure) does not allow for a fully consistent direct approach according to the present state of the art. Several simplifications are thus necessary in order to isolate the most dominant physical aspects and to treat them properly. In this paper, choice was made of semi-analytical modelling for the hydrodynamic part and finite-element modelling for the structural part. Depending on the impact type, different hydrodynamic models are proposed, and the basic principles of hydroelastic coupling are clearly described and validated with respect to the accuracy and convergence of the numerical results.

  15. A tale of twin Higgs: natural twin two Higgs doublet models

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jiang-Hao [Amherst Center for Fundamental Interactions, Department of Physics,University of Massachusetts Amherst,710 North Pleasant St., Amherst, MA 01002 (United States)

    2016-12-28

    In original twin Higgs model, vacuum misalignment between electroweak and new physics scales is realized by adding explicit ℤ{sub 2} breaking term. Introducing additional twin Higgs could accommodate spontaneous ℤ{sub 2} breaking, which explains origin of this misalignment. We introduce a class of twin two Higgs doublet models with most general scalar potential, and discuss general conditions which trigger electroweak and ℤ{sub 2} symmetry breaking. Various scenarios on realising the vacuum misalignment are systematically discussed in a natural composite two Higgs double model framework: explicit ℤ{sub 2} breaking, radiative ℤ{sub 2} breaking, tadpole-induced ℤ{sub 2} breaking, and quartic-induced ℤ{sub 2} breaking. We investigate the Higgs mass spectra and Higgs phenomenology in these scenarios.

  16. Experimental investigations on scaled models for the SNR-2 decay heat removal by natural convection

    International Nuclear Information System (INIS)

    Hoffmann, H.; Weinberg, D.; Tschoeke, H.; Frey, H.H.; Pertmer, G.

    1986-01-01

    Scaled water models are used to prove the mode of function of the decay heat removal by natural convection for the SNR-2. The 2D and 3D models were designed to reach the characteristic numbers (Richardson, Peclet) of the reactor. In the experiments on 2D models the position of the immersed cooler (IC) and the power were varied. Temperature fields and velocities were measured. The IC installed as a separate component in the hot plenum resulted in a very complex flow behavior and low temperatures. Integrating the IC in the IHX showed a very simple circulating flow and high temperatures within the hot plenum. With increasing power only slightly rising temperature differences within the core and IC were detected. Recalculations using the COMMIX 1B code gave qualitatively satisfying results. (author)

  17. A supply model for crude oil and natural gas in the Middle East

    International Nuclear Information System (INIS)

    Chedid, R.; Kobrosly, M.; Ghajar, R.

    2007-01-01

    Crude oil (CO) and natural gas (NG) play an important role in the world economy. The Arab countries (ACs) share 64% of the total oil reserves and 40% of the NG reserves [OPEC, 2003. The Annual Statistical Bulletin]. On the production side, ACs contribute to 30% and 9% of the world production of CO and NG, respectively. Accurate forecast models are needed to do better planning and create less risky business environment. In this paper, an econometric model is built to capture the behavior of CO and NG production in the ESCWA countries. The model is used to forecast future production trends of CO and NG, and thus provide a powerful tool for researchers, planners and investors working in the energy field

  18. Creating a Ruggedness Layer for Use in Habitat Suitability Modeling for Ikh Nart Nature Reserve, Mongolia

    Directory of Open Access Journals (Sweden)

    Nanette Bragin

    2013-12-01

    Full Text Available Spatially-explicit wildlife habitat models are increasingly used to study optimal habitat for species of conservation focus. A ruggedness layer, that summarizes aspect and slope, provides a useful tool for analyses conducted in a Geographic Information System (GIS, such as developing a habitat suitability index model to measure species habitat use. Ruggedness layers prove especially useful in areas where topography represents a key habitat component. We created a ruggedness layer for the Ikh Nart Nature Reserve and surrounding areas in northern Dornogobi Aimag (province, Mongolia. Using a 90 m Shuttle Radar Topography Mission (SRTM digital elevation model (DEM and ArcGIS 10 spatial analyst, we created 9 categories for ruggedness. When combined with other thematic layers such as vegetation, the ruggedness layer becomes a powerful tool for analyzing habitat use by individual animals. The results of such analyses may inform decision makers in protected area planning and conservation of endangered species.

  19. Applicability and perspectives of natural analogues as ''demonstration'' of PAGIS models

    International Nuclear Information System (INIS)

    Girardi, F.; D'Alessandro, M.

    1989-01-01

    In PAGIS Project the safety of the geological disposal system is based on the multibarrier concept, which is reflected in the calculation approach where for all options the behaviour of each barrier is modeled. In the present scheme all the models used for the performance assessment of the disposal options have been considered as a chain of codes describing the behaviour of the different barriers. For each of these, one or more possibilities of verification by Natural Analogue is presented. A set of Tables has been prepared which shows the sequence of phenomena considered for each disposal option. A review of the N.A. as far studied or simply recognized allowed a check to be made on the possibility of verification of the barrier models with the ''long term experiments'' offered by the geological evidence

  20. Physical Cues Controlling Seasonal Immune Allocation in a Natural Piscine Model

    Directory of Open Access Journals (Sweden)

    Alexander Stewart

    2018-03-01

    Full Text Available Seasonal patterns in immunity are frequently observed in vertebrates but are poorly understood. Here, we focused on a natural piscine model, the three-spined stickleback (Gasterosteus aculeatus, and asked how seasonal immune allocation is driven by physical variables (time, light, and heat. Using functionally-relevant gene expression metrics as a reporter of seasonal immune allocation, we synchronously sampled fish monthly from the wild (two habitats, and from semi-natural outdoors mesocosms (stocked from one of the wild habitats. This was repeated across two annual cycles, with continuous within-habitat monitoring of environmental temperature and implementing a manipulation of temperature in the mesocosms. We also conducted a long-term laboratory experiment, subjecting acclimated wild fish to natural and accelerated (×2 photoperiodic change at 7 and 15°C. The laboratory experiment demonstrated that immune allocation was independent of photoperiod and only a very modest effect, at most, was controlled by a tentative endogenous circannual rhythm. On the other hand, experimentally-determined thermal effects were able to quantitatively predict much of the summer–winter fluctuation observed in the field and mesocosms. Importantly, however, temperature was insufficient to fully predict, and occasionally was a poor predictor of, natural patterns. Thermal effects can thus be overridden by other (unidentified natural environmental variation and do not take the form of an unavoidable constraint due to cold-blooded physiology. This is consistent with a context-dependent strategic control of immunity in response to temperature variation, and points to the existence of temperature-sensitive regulatory circuits that might be conserved in other vertebrates.

  1. Natural biotic resources in LCA: Towards an impact assessment model for sustainable supply chain management.

    Science.gov (United States)

    Crenna, Eleonora; Sozzo, Sara; Sala, Serenella

    2018-01-20

    Natural resources, biotic and abiotic, are fundamental from both the ecological and socio-economic point of view, being at the basis of life-support. However, since the demand for finite resources continues to increase, the sustainability of current production and consumption patterns is questioned both in developed and developing countries. A transition towards an economy based on biotic renewable resources (bio-economy) is considered necessary in order to support a steady provision of resources, representing an alternative to an economy based on fossil and abiotic resources. However, to ensure a sustainable use of biotic resources, there is the need of properly accounting for their use along supply chains as well as defining a robust and comprehensive impact assessment model. Since so far naturally occurring biotic resources have gained little attention in impact assessment methods, such as life cycle assessment, the aim of this study is to enable the inclusion of biotic resources in the assessment of products and supply chains. This paper puts forward a framework for biotic resources assessment, including: i) the definition of system boundaries between ecosphere and technosphere, namely between naturally occurring and man-made biotic resources; ii) a list of naturally occurring biotic resources which have a commercial value, as basis for building life cycle inventories (NOBR, e.g. wild animals, plants etc); iii) an impact pathway to identify potential impacts on both resource provision and ecosystem quality; iv) a renewability-based indicator (NOBRri) for the impact assessment of naturally occurring biotic resources, including a list of associated characterization factors. The study, building on a solid review of literature and of available statistical data, highlights and discusses the critical aspects and paradoxes related to biotic resource inclusion in LCA: from the system boundaries definition up to the resource characterization.

  2. Modelling Southern Africa Air Quality and Atmosphere: Importance and Interplay of Natural and Anthropogenic Emissions

    Science.gov (United States)

    Garland, R. M.; Naidoo, M.; Dedekind, Z.; Sibiya, B.; Piketh, S.; Engelbrecht, C. J.; Engelbrecht, F.

    2017-12-01

    Many parts of the southern hemisphere are linked in part due to the strong impact that emissions from natural sources, such as large biomass burning events and marine sources, as well as growing anthropogenic emission sources. Most of southern Africa has an arid to semi-arid climate that is strongly impacted by biomass burning, biogenic and dust emissions. In addition, there are areas of growing industrialization and urbanization that contributes to poor air quality. This air pollution can impact not only human health, but also agriculture, ecosystems, and the climate. This presentation will highlight on-going research to simulate the southern Africa atmosphere and impacts, with a focus on the interplay and relative importance of natural and anthropogenic emissions. The presentation will discuss the simulated sensitivity of the southern African climate to aerosol particles to highlight the importance of natural sources. These historical simulations (1979-2012) were performed with CCAM and are towards the development of the first Africa-led earth systems model. The analysis focused on the simulated sensitivity of the climate and clouds off the southwestern coast of Africa to aerosol particles. The interplay between natural and anthropogenic sources on air pollution will be highlighted using the Waterberg region of South Africa as a case study. CAMx was run at 2km resolution for 2013 using local emission inventories and meteorological output from CCAM to simulate the air quality of the region. These simulations estimate that, on average in the summer, up to 20% of ozone in and around a power plant plume is attributable to biogenic sources of VOCs, with ozone peaks of up to 120ppb; highlighting the importance of understanding the mix of pollutants in this area. In addition to presenting results from this study, the challenges in modelling will be highlighted. These challenges include very few or no measurements that are important to understand, and then accurately

  3. Stochastic model for simulating Souris River Basin precipitation, evapotranspiration, and natural streamflow

    Science.gov (United States)

    Kolars, Kelsey A.; Vecchia, Aldo V.; Ryberg, Karen R.

    2016-02-24

    The Souris River Basin is a 61,000-square-kilometer basin in the Provinces of Saskatchewan and Manitoba and the State of North Dakota. In May and June of 2011, record-setting rains were seen in the headwater areas of the basin. Emergency spillways of major reservoirs were discharging at full or nearly full capacity, and extensive flooding was seen in numerous downstream communities. To determine the probability of future extreme floods and droughts, the U.S. Geological Survey, in cooperation with the North Dakota State Water Commission, developed a stochastic model for simulating Souris River Basin precipitation, evapotranspiration, and natural (unregulated) streamflow. Simulations from the model can be used in future studies to simulate regulated streamflow, design levees, and other structures; and to complete economic cost/benefit analyses.Long-term climatic variability was analyzed using tree-ring chronologies to hindcast precipitation to the early 1700s and compare recent wet and dry conditions to earlier extreme conditions. The extended precipitation record was consistent with findings from the Devils Lake and Red River of the North Basins (southeast of the Souris River Basin), supporting the idea that regional climatic patterns for many centuries have consisted of alternating wet and dry climate states.A stochastic climate simulation model for precipitation, temperature, and potential evapotranspiration for the Souris River Basin was developed using recorded meteorological data and extended precipitation records provided through tree-ring analysis. A significant climate transition was seen around1970, with 1912–69 representing a dry climate state and 1970–2011 representing a wet climate state. Although there were some distinct subpatterns within the basin, the predominant differences between the two states were higher spring through early fall precipitation and higher spring potential evapotranspiration for the wet compared to the dry state.A water

  4. Neutron radiography experiments for verification of soluble boron mixing and transport modeling under natural circulation conditions

    International Nuclear Information System (INIS)

    Morlang, M.M.; Feltus, M.A.

    1996-01-01

    The use of neutron radiography for visualization of fluid flow through flow visualization modules has been very successful. Current experiments at the Penn State Breazeale Reactor serve to verify the mixing and transport of soluble boron under natural flow conditions as would be experienced in a pressurized water reactor. Different flow geometries have been modeled including holes, slots, and baffles. Flow modules are constructed of aluminum box material 1 1/2 inches by 4 inches in varying lengths. An experimental flow system was built which pumps fluid to a head tank and natural circulation flow occurs from the head tank through the flow visualization module to be radio-graphed. The entire flow system is mounted on a portable assembly to allow placement of the flow visualization module in front of the neutron beam port. A neutron-transparent fluor-inert fluid is used to simulate water at different densities. Boron is modeled by gadolinium oxide powder as a tracer element, which is placed in a mixing assembly and injected into the system a remotely operated electric valve, once the reactor is at power. The entire sequence is recorded on real-time video. Still photographs are made frame-by-frame from the video tape. Computers are used to digitally enhance the video and still photographs. The data obtained from the enhancement will be used for verification of simple geometry predictions using the TRAC and RELAP thermal-hydraulic codes. A detailed model of a reactor vessel inlet plenum, downcomer region, flow distribution area and core inlet is being constructed to model the APGOO plenum. Successive radiography experiments of each section of the model under identical conditions will provide a complete vessel / core model for comparison with the thermal-hydraulic codes

  5. Neutron radiography experiments for verification of soluble boron mixing and transport modeling under natural circulation conditions

    International Nuclear Information System (INIS)

    Feltus, M.A.; Morlang, G.M.

    1996-01-01

    The use of neutron radiography for visualization of fluid flow through flow visualization modules has been very successful. Current experiments at the Penn State Breazeale Reactor serve to verify the mixing and transport of soluble boron under natural flow conditions as would be experienced in a pressurized water reactor. Different flow geometries have been modeled including holes, slots, and baffles. Flow modules are constructed of aluminum box material 1 1/2 inches by 4 inches in varying lengths. An experimental flow system was built which pumps fluid to a head tank and natural circulation flow occurs from the head tank through the flow visualization module to be radiographed. The entire flow system is mounted on a portable assembly to allow placement of the flow visualization module in front of the neutron beam port. A neutron-transparent fluorinert fluid is used to simulate water at different densities. Boron is modeled by gadolinium oxide powder as a tracer element, which is placed in a mixing assembly and injected into the system by remote operated electric valve, once the reactor is at power. The entire sequence is recorded on real-time video. Still photographs are made frame-by-frame from the video tape. Computers are used to digitally enhance the video and still photographs. The data obtained from the enhancement will be used for verification of simple geometry predictions using the TRAC and RELAP thermal-hydraulic codes. A detailed model of a reactor vessel inlet plenum, downcomer region, flow distribution area and core inlet is being constructed to model the AP600 plenum. Successive radiography experiments of each section of the model under identical conditions will provide a complete vessel/core model for comparison with the thermal-hydraulic codes

  6. Kinetic Adsorption Study of Silver Nanoparticles on Natural Zeolite: Experimental and Theoretical Models

    Directory of Open Access Journals (Sweden)

    Alvaro Ruíz-Baltazar

    2015-12-01

    Full Text Available In this research, the adsorption capacity of Ag nanoparticles on natural zeolite from Oaxaca is presented. In order to describe the adsorption mechanism of silver nanoparticles on zeolite, experimental adsorption models for Ag ions and Ag nanoparticles were carried out. These experimental data obtained by the atomic absorption spectrophotometry technique were compared with theoretical models such as Lagergren first-order, pseudo-second-order, Elovich, and intraparticle diffusion. Correlation factors R2 of the order of 0.99 were observed. Analysis by transmission electron microscopy describes the distribution of the silver nanoparticles on the zeolite outer surface. Additionally, a chemical characterization of the material was carried out through a dilution process with lithium metaborate. An average value of 9.3 in the Si/Al ratio was observed. Factors such as the adsorption behavior of the silver ions and the Si/Al ratio of the zeolite are very important to support the theoretical models and establish the adsorption mechanism of Ag nanoparticles on natural zeolite.

  7. Using hydrogeochemical data from natural environments to improve models of radionuclide speciation in groundwaters

    International Nuclear Information System (INIS)

    Read, D.; Hooker, P.

    1991-01-01

    It is essential that computer-based models used in the safety assessment of radioactive waste repositories accurately represent the processes occurring in real field systems. Confidence in long-term predictions of radionuclide migration will then depend upon the completeness of data available, particularly those obtained from the disposal site, and correct implementation of the model. The study of natural geochemical systems provides information on the adequacy of the underlying generic database and enhances our understanding of the transport mechanisms which form the basis of performance assessment. This paper concentrates on speciation-solubility modelling and describes four natural occurrences of uranium, each of which displays a different facet of uranium migration behaviour. The attributes of each site and the means by which uranium is immobilised are described. Retardation is highly species specific and this is illustrated through the use of site data in equilibrium speciation and coupled chemical transport calculations. Oxidation of U(IV) to U(VI) species promotes leaching of uranium ore at all the locations studied, emphasising the need to ensure that reducing conditions persist in a repository dominated by its actinide inventory. 5 figs., 46 refs

  8. A distribution planning model for natural gas supply chain: A case study

    International Nuclear Information System (INIS)

    Hamedi, Maryam; Zanjirani Farahani, Reza; Husseini, Mohammad Moattar; Esmaeilian, Gholam Reza

    2009-01-01

    In this paper, a real-world case study of a natural gas supply chain is investigated. By using concepts related to natural gas industry and the relations among the components of transmission and distribution network, a six-level supply chain has been introduced and presented schematically. The defined supply chain is a single-objective, multi-period, and single-product problem that is formulated as a mixed integer non-linear programming model, which can easily be linearized. The objective of this model is to minimize direct or indirect distribution costs. There are six groups of constraints including capacity, input and output balancing, demand satisfaction, network flow continuity, and relative constraints to the required binary variables. The solution algorithm of the problem is hierarchical; in each step, one section of the problem is solved using an exact method; the outputs of this section are passed to the next relative section as inputs. Finally, it is shown that the problem has been solved in a reasonable time and desirable results are attained. The use of proposed model and its solution approach have been studied in two gas trunk lines, to present the priority of its cost saving

  9. A model for the calculation of the radiation dose from natural radionuclides in The Netherlands

    International Nuclear Information System (INIS)

    Ackers, J.G.

    1986-02-01

    A model has been developed to calculate the radiation dose incurred from natural radioactivity indoors and outdoors, expressed in effective dose equivalence/year. The model is applied on a three rooms dwelling characterized by interconnecting air flows and on a dwelling with crawlspace. In this model the distinct parameters are variable in order to allow the investigation of the relative influence. The calculated effective dose equivalent for an adult in the dwelling was calculated to be about 1.7 mSv/year, composed of 15% from cosmic radiation, 35% from terrestrial radioactivity, 20% from radioactivity in the body and 30% from natural radionuclides in building materials. The calculations show an enhancement of about a factor of two in radon concentration in air in a room which is ventilated by air from an adjacent room. It is also shown that the attachment rate of radon products to aerosols and the plate-out effect are relatively important parameters influencing the magnitude of the dose rate. (Auth.)

  10. Towards modelling flood protection investment as a coupled human and natural system

    Science.gov (United States)

    O'Connell, P. E.; O'Donnell, G.

    2014-01-01

    Due to a number of recent high-profile flood events and the apparent threat from global warming, governments and their agencies are under pressure to make proactive investments to protect people living in floodplains. However, adopting a proactive approach as a universal strategy is not affordable. It has been argued that delaying expensive and essentially irreversible capital decisions could be a prudent strategy in situations with high future uncertainty. This paper firstly uses Monte Carlo simulation to explore the performance of proactive and reactive investment strategies using a rational cost-benefit approach in a natural system with varying levels of persistence/interannual variability in annual maximum floods. It is found that, as persistence increases, there is a change in investment strategy optimality from proactive to reactive. This could have implications for investment strategies under the increasingly variable climate that is expected with global warming. As part of the emerging holistic approaches to flood risk management, there is increasing emphasis on stakeholder participation in determining where and when flood protection investments are made, and so flood risk management is becoming more people-centred. As a consequence, multiple actors are involved in the decision-making process, and the social sciences are assuming an increasingly important role in flood risk management. There is a need for modelling approaches which can couple the natural and human system elements. It is proposed that coupled human and natural system (CHANS) modelling could play an important role in understanding the motivations, actions and influence of citizens and institutions and how these impact on the effective delivery of flood protection investment. A framework for using agent-based modelling of human activities leading to flood investments is outlined, and some of the challenges associated with implementation are discussed.

  11. Two-phase modelling of thermal dissipation in a natural basin

    International Nuclear Information System (INIS)

    Baltrenas, P.; Vaitiekunas, P.; Katinas, V.; Markevicius, A.

    2004-01-01

    The state of two-phase flow 'liquid-gas' has been modeled numerically by the three-dimensional method of complex research of heat and mass transfer. This allows examining the interaction of some transfer processes in a natural cooling basin (the Druksiai lake): the wind power and direction, variable water density, the coefficient of heat conduction and heat transfer of the water-air interface. Combined effect of these natural actions determines the heat amount that the basin is able to dissipate to the surrounding atmospheric media in thermal equilibrium (without changes in the mean water temperature). This paper presents a number of the most widely used expressions for the coefficients of vertical and horizontal heat transfer. On the basis of stream velocity and mean temperature profiles measured in the cooling pond as well as on that of their time variations suggestions are made that the mixing rate at the water surface is caused by natural space - time variation of the wind, and can be described by the value of eddy viscosity coefficient - 1 m2/s (numerical modeling with 0,9-1,3 m2/s). The wind influences the surface of the lake according to the experimental data, i e 1-3 % of the mean wind velocity. The model applies to the weakly wind, approximately 1-5 m/s of the mean wind velocity. Comparison of experimental and numerical results showed a qualitative agreement. For a better quantitative approximation, it is necessary to have more boundary conditions variable with time and to solve unsteady set equations for transfer processes. (author)

  12. A precipitation-induced landslide susceptibility model for natural gas transmission pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Finley, Jason P. [Fugro William Lettis and Associates, Inc., Valencia, California (United States); Slayter, David L.; Hitchcock, Chris S. [Fugro William Lettis and Associates, Inc., Walnut Creek, California (United States); Lee, Chih-Hung [Pacific Gas and Electric Company, Gas Systems Integrity Management, Walnut Creek, California (United States)

    2010-07-01

    Landslides related to heavy rainfall can cause extensive damage to natural gas transmission pipelines. Fugro William Lettis and Associates Inc. have developed and implemented a geographic information system (GIS) model that evaluates near real-time precipitation-induced landslide susceptibility. The model incorporates state-wide precipitation data and geologically-based landslide classifications to produce rapid landslide risk evaluation for Pacific Gas and Electric Company's (PGandE) gas transmission system during winter rain storms in California. The precipitation data include pre-storm event quantitative precipitation forecasts (QPF) and post-storm event quantitative precipitation estimate (QPE) from the United States National Oceanic and Atmospheric Administration (NOAA). The geologic classifications are based on slope, susceptible geologic formations, and the locations of historic or known landslide occurrences. Currently the model is calibrated using qualitative measures. This paper describes the development of the model algorithm and input data, model results, calibration efforts, and the on-going research and landslide collection warranted for continued refinement of the model.

  13. Application of atomic force microscopy to the study of natural and model soil particles.

    Science.gov (United States)

    Cheng, S; Bryant, R; Doerr, S H; Rhodri Williams, P; Wright, C J

    2008-09-01

    The structure and surface chemistry of soil particles has extensive impact on many bulk scale properties and processes of soil systems and consequently the environments that they support. There are a number of physiochemical mechanisms that operate at the nanoscale which affect the soil's capability to maintain native vegetation and crops; this includes soil hydrophobicity and the soil's capacity to hold water and nutrients. The present study used atomic force microscopy in a novel approach to provide unique insight into the nanoscale properties of natural soil particles that control the physiochemical interaction of material within the soil column. There have been few atomic force microscopy studies of soil, perhaps a reflection of the heterogeneous nature of the system. The present study adopted an imaging and force measurement research strategy that accounted for the heterogeneity and used model systems to aid interpretation. The surface roughness of natural soil particles increased with depth in the soil column a consequence of the attachment of organic material within the crevices of the soil particles. The roughness root mean square calculated from ten 25 microm(2) images for five different soil particles from a Netherlands soil was 53.0 nm, 68.0 nm, 92.2 nm and 106.4 nm for the respective soil depths of 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm. A novel analysis method of atomic force microscopy phase images based on phase angle distribution across a surface was used to interpret the nanoscale distribution of organic material attached to natural and model soil particles. Phase angle distributions obtained from phase images of model surfaces were found to be bimodal, indicating multiple layers of material, which changed with the concentration of adsorbed humic acid. Phase angle distributions obtained from phase images of natural soil particles indicated a trend of decreasing surface coverage with increasing depth in the soil column. This was consistent with

  14. Natural Environment Modeling and Fault-Diagnosis for Automated Agricultural Vehicle

    DEFF Research Database (Denmark)

    Blas, Morten Rufus; Blanke, Mogens

    2008-01-01

    This paper presents results for an automatic navigation system for agricultural vehicles. The system uses stereo-vision, inertial sensors and GPS. Special emphasis has been placed on modeling the natural environment in conjunction with a fault-tolerant navigation system. The results are exemplified...... by an agricultural vehicle following cut grass (swath). It is demonstrated how faults in the system can be detected and diagnosed using state of the art techniques from fault-tolerant literature. Results in performing fault-diagnosis and fault accomodation are presented using real data....

  15. A large-scale linear complementarity model of the North American natural gas market

    International Nuclear Information System (INIS)

    Gabriel, Steven A.; Jifang Zhuang; Kiet, Supat

    2005-01-01

    The North American natural gas market has seen significant changes recently due to deregulation and restructuring. For example, third party marketers can contract for transportation and purchase of gas to sell to end-users. While the intent was a more competitive market, the potential for market power exists. We analyze this market using a linear complementarity equilibrium model including producers, storage and peak gas operators, third party marketers and four end-use sectors. The marketers are depicted as Nash-Cournot players determining supply to meet end-use consumption, all other players are in perfect competition. Results based on National Petroleum Council scenarios are presented. (Author)

  16. Mathematical Model and Program for the Sizing of Counter-flow Natural Draft Wet Cooling Towers

    Directory of Open Access Journals (Sweden)

    Victor-Eduard Cenușă

    2017-08-01

    Full Text Available Assuring the necessary temperature and mass flow rate of the cooling water to the condenser represents an essential condition for the efficient operation of a steam power plant. The paper presents equations which describe the physical phenomena and the mathematical model for the design of counter-flow natural draft wet cooling towers. Following is given the flow-chart of the associated computer program. A case study is made to show the results of the computer program and emphasize the interdependence between the main design parameters.

  17. Natural Disasters in a Two-Sector Model of Endogenous Growth

    OpenAIRE

    Masako Ikefuji; Ryo Horii

    2006-01-01

    Using an endogenous growth model with physical and human capital accumulation, this paper considers the sustainability of economic growth when the use of a polluting input (e.g., fossil fuels) intensifies the risk of capital destruction through natural disasters. We find that growth is sustainable only if the tax rate on the polluting input increases over time. The long-term rate of economic growth follows an inverted V-shaped curve relative to the growth rate of the environmental tax, and it...

  18. Immersion freezing by natural dust based on a soccer ball model with the Community Atmospheric Model version 5: climate effects

    Science.gov (United States)

    Wang, Yong; Liu, Xiaohong

    2014-12-01

    We introduce a simplified version of the soccer ball model (SBM) developed by Niedermeier et al (2014 Geophys. Res. Lett. 41 736-741) into the Community Atmospheric Model version 5 (CAM5). It is the first time that SBM is used in an atmospheric model to parameterize the heterogeneous ice nucleation. The SBM, which was simplified for its suitable application in atmospheric models, uses the classical nucleation theory to describe the immersion/condensation freezing by dust in the mixed-phase cloud regime. Uncertain parameters (mean contact angle, standard deviation of contact angle probability distribution, and number of surface sites) in the SBM are constrained by fitting them to recent natural dust (Saharan dust) datasets. With the SBM in CAM5, we investigate the sensitivity of modeled cloud properties to the SBM parameters, and find significant seasonal and regional differences in the sensitivity among the three SBM parameters. Changes of mean contact angle and the number of surface sites lead to changes of cloud properties in Arctic in spring, which could be attributed to the transport of dust ice nuclei to this region. In winter, significant changes of cloud properties induced by these two parameters mainly occur in northern hemispheric mid-latitudes (e.g., East Asia). In comparison, no obvious changes of cloud properties caused by changes of standard deviation can be found in all the seasons. These results are valuable for understanding the heterogeneous ice nucleation behavior, and useful for guiding the future model developments.

  19. Immersion freezing by natural dust based on a soccer ball model with the Community Atmospheric Model version 5: climate effects

    International Nuclear Information System (INIS)

    Wang, Yong; Liu, Xiaohong

    2014-01-01

    We introduce a simplified version of the soccer ball model (SBM) developed by Niedermeier et al (2014 Geophys. Res. Lett. 41 736–741) into the Community Atmospheric Model version 5 (CAM5). It is the first time that SBM is used in an atmospheric model to parameterize the heterogeneous ice nucleation. The SBM, which was simplified for its suitable application in atmospheric models, uses the classical nucleation theory to describe the immersion/condensation freezing by dust in the mixed-phase cloud regime. Uncertain parameters (mean contact angle, standard deviation of contact angle probability distribution, and number of surface sites) in the SBM are constrained by fitting them to recent natural dust (Saharan dust) datasets. With the SBM in CAM5, we investigate the sensitivity of modeled cloud properties to the SBM parameters, and find significant seasonal and regional differences in the sensitivity among the three SBM parameters. Changes of mean contact angle and the number of surface sites lead to changes of cloud properties in Arctic in spring, which could be attributed to the transport of dust ice nuclei to this region. In winter, significant changes of cloud properties induced by these two parameters mainly occur in northern hemispheric mid-latitudes (e.g., East Asia). In comparison, no obvious changes of cloud properties caused by changes of standard deviation can be found in all the seasons. These results are valuable for understanding the heterogeneous ice nucleation behavior, and useful for guiding the future model developments. (letter)

  20. Using natural selection and optimization for smarter vegetation models - challenges and opportunities

    Science.gov (United States)

    Franklin, Oskar; Han, Wang; Dieckmann, Ulf; Cramer, Wolfgang; Brännström, Åke; Pietsch, Stephan; Rovenskaya, Elena; Prentice, Iain Colin

    2017-04-01

    Dynamic global vegetation models (DGVMs) are now indispensable for understanding the biosphere and for estimating the capacity of ecosystems to provide services. The models are continuously developed to include an increasing number of processes and to utilize the growing amounts of observed data becoming available. However, while the versatility of the models is increasing as new processes and variables are added, their accuracy suffers from the accumulation of uncertainty, especially in the absence of overarching principles controlling their concerted behaviour. We have initiated a collaborative working group to address this problem based on a 'missing law' - adaptation and optimization principles rooted in natural selection. Even though this 'missing law' constrains relationships between traits, and therefore can vastly reduce the number of uncertain parameters in ecosystem models, it has rarely been applied to DGVMs. Our recent research have shown that optimization- and trait-based models of gross primary production can be both much simpler and more accurate than current models based on fixed functional types, and that observed plant carbon allocations and distributions of plant functional traits are predictable with eco-evolutionary models. While there are also many other examples of the usefulness of these and other theoretical principles, it is not always straight-forward to make them operational in predictive models. In particular on longer time scales, the representation of functional diversity and the dynamical interactions among individuals and species presents a formidable challenge. Here we will present recent ideas on the use of adaptation and optimization principles in vegetation models, including examples of promising developments, but also limitations of the principles and some key challenges.

  1. Using the Data From Accidents and Natural Disasters to Improve Marine Debris Modeling

    Science.gov (United States)

    Maximenko, N. A.; Hafner, J.; MacFadyen, A.; Kamachi, M.; Murray, C. C.

    2016-02-01

    In the absence of satisfactory marine debris observing system, drift models provide a unique tool that can be used to identify main pathways and accumulation areas of the natural and anthropogenic debris, including the plastic pollution having increasing impact on the environment and raising concern of the society. Main problems, limiting the utility of model simulations, include the lack of accurate information on distribution, timing, strength and composition of sources of marine debris and the complexity of the hydrodynamics of an object, floating on the surface of a rough sea. To calculate the drift, commonly, models estimate surface currents first and then add the object motion relative to the water. Importantly, ocean surface velocity can't be measured with the existing instruments. For various applications it is derived from subsurface (such as 15-meter drifter trajectories) and satellite (altimetry, scatterometry) data using simple theories (geostrophy, Ekman spiral, etc.). Similarly, even the best ocean general circulation models (OGCM's), utilizing different parameterizations of the mixed layer, significantly disagree on the ocean surface velocities. Understanding debris motion under the direct wind force and in interaction with the breaking wind waves seems to be a task of even greater complexity. In this presentation, we demonstrate how the data of documented natural disasters (such as tsunamis, hurricanes and floods) and other accidents generating marine debris with known times and coordinates of start and/or end points of the trajectories, can be used to calibrate drift models and obtain meaningful quantitative results that can be generalized for other sources of debris and used to plan the future marine debris observing system. On these examples we also demonstrate how the oceanic and atmospheric circulations couple together to determine the pathways and destination areas of different types of the floating marine debris.

  2. Assessment of CO2 Storage Potential in Naturally Fractured Reservoirs With Dual-Porosity Models

    Science.gov (United States)

    March, Rafael; Doster, Florian; Geiger, Sebastian

    2018-03-01

    Naturally Fractured Reservoirs (NFR's) have received little attention as potential CO2 storage sites. Two main facts deter from storage projects in fractured reservoirs: (1) CO2 tends to be nonwetting in target formations and capillary forces will keep CO2 in the fractures, which typically have low pore volume; and (2) the high conductivity of the fractures may lead to increased spatial spreading of the CO2 plume. Numerical simulations are a powerful tool to understand the physics behind brine-CO2 flow in NFR's. Dual-porosity models are typically used to simulate multiphase flow in fractured formations. However, existing dual-porosity models are based on crude approximations of the matrix-fracture fluid transfer processes and often fail to capture the dynamics of fluid exchange accurately. Therefore, more accurate transfer functions are needed in order to evaluate the CO2 transfer to the matrix. This work presents an assessment of CO2 storage potential in NFR's using dual-porosity models. We investigate the impact of a system of fractures on storage in a saline aquifer, by analyzing the time scales of brine drainage by CO2 in the matrix blocks and the maximum CO2 that can be stored in the rock matrix. A new model to estimate drainage time scales is developed and used in a transfer function for dual-porosity simulations. We then analyze how injection rates should be limited in order to avoid early spill of CO2 (lost control of the plume) on a conceptual anticline model. Numerical simulations on the anticline show that naturally fractured reservoirs may be used to store CO2.

  3. Incorporating Ecosystem Processes Controlling Carbon Balance Into Models of Coupled Human-Natural Systems

    Science.gov (United States)

    Currie, W.; Brown, D. G.; Brunner, A.; Fouladbash, L.; Hadzick, Z.; Hutchins, M.; Kiger, S. E.; Makino, Y.; Nassauer, J. I.; Robinson, D. T.; Riolo, R. L.; Sun, S.

    2012-12-01

    A key element in the study of coupled human-natural systems is the interactions of human populations with vegetation and soils. In human-dominated landscapes, vegetation production and change results from a combination of ecological processes and human decision-making and behavior. Vegetation is often dramatically altered, whether to produce food for humans and livestock, to harvest fiber for construction and other materials, to harvest fuel wood or feedstock for biofuels, or simply for cultural preferences as in the case of residential lawns with sparse trees in the exurban landscape. This alteration of vegetation and its management has a substantial impact on the landscape carbon balance. Models can be used to simulate scenarios in human-natural systems and to examine the integration of processes that determine future trajectories of carbon balance. However, most models of human-natural systems include little integration of the human alteration of vegetation with the ecosystem processes that regulate carbon balance. Here we illustrate a few case studies of pilot-study models that strive for this integration from our research across various types of landscapes. We focus greater detail on a fully developed research model linked to a field study of vegetation and soils in the exurban residential landscape of Southeastern Michigan, USA. The field study characterized vegetation and soil carbon storage in 5 types of ecological zones. Field-observed carbon storage in the vegetation in these zones ranged widely, from 150 g C/m2 in turfgrass zones, to 6,000 g C/m2 in zones defined as turfgrass with sparse woody vegetation, to 16,000 g C/m2 in a zone defined as dense trees and shrubs. Use of these zones facilitated the scaling of carbon pools to the landscape, where the areal mixtures of zone types had a significant impact on landscape C storage. Use of these zones also facilitated the use of the ecosystem process model Biome-BGC to simulate C trajectories and also

  4. Natural treatment system models for wastewater management: a study from Hyderabad, India.

    Science.gov (United States)

    Sonkamble, Sahebrao; Wajihuddin, Md; Jampani, Mahesh; Sarah, S; Somvanshi, V K; Ahmed, Shakeel; Amerasinghe, Priyanie; Boisson, Alexandre

    2018-01-01

    Wastewater generated on a global scale has become a significant source of water resources which necessitates appropriate management strategies. However, the complexities associated with wastewater are lack of economically viable treatment systems, especially in low- and middle-income countries. While many types of treatment systems are needed to serve the various local issues, we propose natural treatment systems (NTS) such as natural wetlands that are eco-friendly, cost-effective, and can be jointly driven by public bodies and communities. In order for it to be part of wastewater management, this study explores the NTS potential for removal of pollutants, cost-effectiveness, and reuse options for the 1.20 million m 3 /day of wastewater generated in Hyderabad, India. The pilot study includes hydro-geophysical characterization of natural wetland to determine pollutant removal efficiency and its effective utilization for treated wastewater in the peri-urban habitat. The results show the removal of organic content (76-78%), nutrients (77-97%), and microbes (99.5-99.9%) from the wetland-treated wastewater and its suitability for agriculture applications. Furthermore, the wetland efficiency integrated with engineered interventions led to the development of NTS models with different application scenarios: (i) constructed wetlands, (ii) minimized community wetlands, and (iii) single outlet system, suitable for urban, peri-urban and rural areas, respectively.

  5. Treatment of a multiple sclerosis animal model by a novel nanodrop formulation of a natural antioxidant.

    Science.gov (United States)

    Binyamin, Orli; Larush, Liraz; Frid, Kati; Keller, Guy; Friedman-Levi, Yael; Ovadia, Haim; Abramsky, Oded; Magdassi, Shlomo; Gabizon, Ruth

    2015-01-01

    Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system and is associated with demyelination, neurodegeneration, and sensitivity to oxidative stress. In this work, we administered a nanodroplet formulation of pomegranate seed oil (PSO), denominated Nano-PSO, to mice induced for experimental autoimmune encephalomyelitis (EAE), an established model of MS. PSO comprises high levels of punicic acid, a unique polyunsaturated fatty acid considered as one of the strongest natural antioxidants. We show here that while EAE-induced mice treated with natural PSO presented some reduction in disease burden, this beneficial effect increased significantly when EAE mice were treated with Nano-PSO of specific size nanodroplets at much lower concentrations of the oil. Pathological examinations revealed that Nano-PSO administration dramatically reduced demyelination and oxidation of lipids in the brains of the affected animals, which are hallmarks of this severe neurological disease. We propose that novel formulations of natural antioxidants such as Nano-PSO may be considered for the treatment of patients suffering from demyelinating diseases. On the mechanistic side, our results demonstrate that lipid oxidation may be a seminal feature in both demyelination and neurodegeneration.

  6. Contextual interactions in grating plaid configurations are explained by natural image statistics and neural modeling

    Directory of Open Access Journals (Sweden)

    Udo Alexander Ernst

    2016-10-01

    Full Text Available Processing natural scenes requires the visual system to integrate local features into global object descriptions. To achieve coherent representations, the human brain uses statistical dependencies to guide weighting of local feature conjunctions. Pairwise interactions among feature detectors in early visual areas may form the early substrate of these local feature bindings. To investigate local interaction structures in visual cortex, we combined psychophysical experiments with computational modeling and natural scene analysis. We first measured contrast thresholds for 2x2 grating patch arrangements (plaids, which differed in spatial frequency composition (low, high or mixed, number of grating patch co-alignments (0, 1 or 2, and inter-patch distances (1° and 2° of visual angle. Contrast thresholds for the different configurations were compared to the prediction of probability summation (PS among detector families tuned to the four retinal positions. For 1° distance the thresholds for all configurations were larger than predicted by PS, indicating inhibitory interactions. For 2° distance, thresholds were significantly lower compared to PS when the plaids were homogeneous in spatial frequency and orientation, but not when spatial frequencies were mixed or there was at least one misalignment. Next, we constructed a neural population model with horizontal laminar structure, which reproduced the detection thresholds after adaptation of connection weights. Consistent with prior work, contextual interactions were medium-range inhibition and long-range, orientation-specific excitation. However, inclusion of orientation-specific, inhibitory interactions between populations with different spatial frequency preferences were crucial for explaining detection thresholds. Finally, for all plaid configurations we computed their likelihood of occurrence in natural images. The likelihoods turned out to be inversely related to the detection thresholds obtained

  7. Metabolic network modeling of microbial interactions in natural and engineered environmental systems

    Directory of Open Access Journals (Sweden)

    Octavio ePerez-Garcia

    2016-05-01

    Full Text Available We review approaches to characterize metabolic interactions within microbial communities using Stoichiometric Metabolic Network (SMN models for applications in environmental and industrial biotechnology. SMN models are computational tools used to evaluate the metabolic engineering potential of various organisms. They have successfully been applied to design and optimize the microbial production of antibiotics, alcohols and amino acids by single strains. To date however, such models have been rarely applied to analyze and control the metabolism of more complex microbial communities. This is largely attributed to the diversity of microbial community functions, metabolisms and interactions. Here, we firstly review different types of microbial interaction and describe their relevance for natural and engineered environmental processes. Next, we provide a general description of the essential methods of the SMN modeling workflow including the steps of network reconstruction, simulation through Flux Balance Analysis (FBA, experimental data gathering, and model calibration. Then we broadly describe and compare four approaches to model microbial interactions using metabolic networks, i.e. i lumped networks, ii compartment per guild networks, iii bi-level optimization simulations and iv dynamic-SMN methods. These approaches can be used to integrate and analyze diverse microbial physiology, ecology and molecular community data. All of them (except the lumped approach are suitable for incorporating species abundance data but so far they have been used only to model simple communities of two to eight different species. Interactions based on substrate exchange and competition can be directly modeled using the above approaches. However, interactions based on metabolic feedbacks, such as product inhibition and synthropy require extensions to current models, incorporating gene regulation and compounding accumulation mechanisms. SMN models of microbial

  8. Measurements of indoor and outdoor natural radiation exposure rates in model houses

    International Nuclear Information System (INIS)

    Matsuda, Hideharu; Fukaya, Mitsuharu; Minato, Susumu

    1990-01-01

    Natural gamma-ray and cosmic-ray exposure rates were measured indoors and outdoors for 94 model houses of four housing centers in Nagoya to obtain basic data for estimation of the population dose. Influence of the structure of houses on indoor exposure rates and relationship between indoor and outdoor natural gamma-ray exposure rates were studied. Exposure rates were measured with a 1.5'' φ x 4'' NaI (Tl) scintillation counter and a 6''φ spherical plastic scintillation counter. The mean indoor natural gamma-ray exposure rate in ferro-concrete buildings was about 40% higher than that in fireproof wooden houses, about 60% higher than that in light-weight steel-framed buildings, in fireproof wooden houses, it was also about 10% higher than in light-weight steel-framed building. The ratio of indoor to outdoor natural gamma-ray exposure rate was found to be about 0.95±0.15, 0.77±0.10, and 0.72±0.13 for ferro-concrete buildings, fireproof wooden houses and light-weight steel-framed buildings, respectively. The mean indoor cosmic-ray exposure rate in ferro-concrete buildings was 2.8 μR/h, about 18% lower than the outdoors. The indoor cosmic-ray exposure rate in fireproof wooden houses and light-weight steel-framed buildings were 3.2 μR/h, about 6% lower than the outdoors. (author)

  9. Finite element model updating of natural fibre reinforced composite structure in structural dynamics

    Directory of Open Access Journals (Sweden)

    Sani M.S.M.

    2016-01-01

    Full Text Available Model updating is a process of making adjustment of certain parameters of finite element model in order to reduce discrepancy between analytical predictions of finite element (FE and experimental results. Finite element model updating is considered as an important field of study as practical application of finite element method often shows discrepancy to the test result. The aim of this research is to perform model updating procedure on a composite structure as well as trying improving the presumed geometrical and material properties of tested composite structure in finite element prediction. The composite structure concerned in this study is a plate of reinforced kenaf fiber with epoxy. Modal properties (natural frequency, mode shapes, and damping ratio of the kenaf fiber structure will be determined using both experimental modal analysis (EMA and finite element analysis (FEA. In EMA, modal testing will be carried out using impact hammer test while normal mode analysis using FEA will be carried out using MSC. Nastran/Patran software. Correlation of the data will be carried out before optimizing the data from FEA. Several parameters will be considered and selected for the model updating procedure.

  10. Probabilistic models for neural populations that naturally capture global coupling and criticality.

    Science.gov (United States)

    Humplik, Jan; Tkačik, Gašper

    2017-09-01

    Advances in multi-unit recordings pave the way for statistical modeling of activity patterns in large neural populations. Recent studies have shown that the summed activity of all neurons strongly shapes the population response. A separate recent finding has been that neural populations also exhibit criticality, an anomalously large dynamic range for the probabilities of different population activity patterns. Motivated by these two observations, we introduce a class of probabilistic models which takes into account the prior knowledge that the neural population could be globally coupled and close to critical. These models consist of an energy function which parametrizes interactions between small groups of neurons, and an arbitrary positive, strictly increasing, and twice differentiable function which maps the energy of a population pattern to its probability. We show that: 1) augmenting a pairwise Ising model with a nonlinearity yields an accurate description of the activity of retinal ganglion cells which outperforms previous models based on the summed activity of neurons; 2) prior knowledge that the population is critical translates to prior expectations about the shape of the nonlinearity; 3) the nonlinearity admits an interpretation in terms of a continuous latent variable globally coupling the system whose distribution we can infer from data. Our method is independent of the underlying system's state space; hence, it can be applied to other systems such as natural scenes or amino acid sequences of proteins which are also known to exhibit criticality.

  11. Naturalness and lepton number/flavor violation in inverse seesaw models

    Energy Technology Data Exchange (ETDEWEB)

    Haba, Naoyuki [Graduate School of Science and Engineering, Shimane University,1060, Nishikawatsu, Matsue, Shimane (Japan); Ishida, Hiroyuki [Graduate School of Science and Engineering, Shimane University,1060, Nishikawatsu, Matsue, Shimane (Japan); Physics Division, National Center for Theoretical Sciences,101, Section 2 Kuang Fu Road, Hsinchu, 300 Taiwan (China); Yamaguchi, Yuya [Graduate School of Science and Engineering, Shimane University,1060, Nishikawatsu, Matsue, Shimane (Japan); Department of Physics, Faculty of Science, Hokkaido University,Kita 9 Nishi 8, Kita-ku, Sapporo, Hokkaido (Japan)

    2016-11-02

    We introduce three right-handed neutrinos and three sterile neutrinos, and consider an inverse seesaw mechanism for neutrino mass generation. From naturalness point of view, their Majorana masses should be small, while it induces a large neutrino Yukawa coupling. Then, a neutrinoless double beta decay rate can be enhanced, and a sizable Higgs mass correction is inevitable. We find that the enhancement rate can be more than ten times compared with a standard prediction from light neutrino contribution alone, and an analytic form of heavy neutrino contributions to the Higgs mass correction. In addition, we numerically analyze the model, and find almost all parameter space of the model can be complementarily searched by future experiments of neutrinoless double beta decay and μ→e conversion.

  12. Natural Aggregation Approach based Home Energy Manage System with User Satisfaction Modelling

    Science.gov (United States)

    Luo, F. J.; Ranzi, G.; Dong, Z. Y.; Murata, J.

    2017-07-01

    With the prevalence of advanced sensing and two-way communication technologies, Home Energy Management System (HEMS) has attracted lots of attentions in recent years. This paper proposes a HEMS that optimally schedules the controllable Residential Energy Resources (RERs) in a Time-of-Use (TOU) pricing and high solar power penetrated environment. The HEMS aims to minimize the overall operational cost of the home, and the user’s satisfactions and requirements on the operation of different household appliances are modelled and considered in the HEMS. Further, a new biological self-aggregation intelligence based optimization technique previously proposed by the authors, i.e., Natural Aggregation Algorithm (NAA), is applied to solve the proposed HEMS optimization model. Simulations are conducted to validate the proposed method.

  13. An analysis of Canada-US natural gas trade using the AGAS energy model

    International Nuclear Information System (INIS)

    Quon, D.; Wong, S.

    1989-01-01

    The strength of AGAS is that it was structurally designed to address the primary issue of EMF9, namely the medium and long-term prospects for Canada-US natural gas trade. Consequently, it is one of the very few models with the following necessary features: (1) it treats all the regions of Canada and the United States as one continental entity, both with respect to demand and supply; (2) All regional supplies and demands are integrated. Hence, regional gas prices are endogenous; inter-regional gas flows, including Canadian-US gas exchanges, are endogenous. Models that do not have both of these features require that the answers that are being sought have to be specified exogenously. An iterative procedure can be used to reconcile unrealistic results but only with difficulty

  14. Modelling with the master equation solution methods and applications in social and natural sciences

    CERN Document Server

    Haag, Günter

    2017-01-01

    This book presents the theory and practical applications of the Master equation approach, which provides a powerful general framework for model building in a variety of disciplines. The aim of the book is to not only highlight different mathematical solution methods, but also reveal their potential by means of practical examples. Part I of the book, which can be used as a toolbox, introduces selected statistical fundamentals and solution methods for the Master equation. In Part II and Part III, the Master equation approach is applied to important applications in the natural and social sciences. The case studies presented mainly hail from the social sciences, including urban and regional dynamics, population dynamics, dynamic decision theory, opinion formation and traffic dynamics; however, some applications from physics and chemistry are treated as well, underlining the interdisciplinary modelling potential of the Master equation approach. Drawing upon the author’s extensive teaching and research experience...

  15. Finding water scarcity amid abundance using human-natural system models.

    Science.gov (United States)

    Jaeger, William K; Amos, Adell; Bigelow, Daniel P; Chang, Heejun; Conklin, David R; Haggerty, Roy; Langpap, Christian; Moore, Kathleen; Mote, Philip W; Nolin, Anne W; Plantinga, Andrew J; Schwartz, Cynthia L; Tullos, Desiree; Turner, David P

    2017-11-07

    Water scarcity afflicts societies worldwide. Anticipating water shortages is vital because of water's indispensable role in social-ecological systems. But the challenge is daunting due to heterogeneity, feedbacks, and water's spatial-temporal sequencing throughout such systems. Regional system models with sufficient detail can help address this challenge. In our study, a detailed coupled human-natural system model of one such region identifies how climate change and socioeconomic growth will alter the availability and use of water in coming decades. Results demonstrate how water scarcity varies greatly across small distances and brief time periods, even in basins where water may be relatively abundant overall. Some of these results were unexpected and may appear counterintuitive to some observers. Key determinants of water scarcity are found to be the cost of transporting and storing water, society's institutions that circumscribe human choices, and the opportunity cost of water when alternative uses compete. Published under the PNAS license.

  16. Modeling the natural UV irradiation and comparative UV measurements at Moussala BEO (BG)

    Science.gov (United States)

    Tyutyundzhiev, N.; Angelov, Ch; Lovchinov, K.; Nitchev, Hr; Petrov, M.; Arsov, T.

    2018-03-01

    Studies of and modeling the impact of natural UV irradiation on the human population are of significant importance for human activity and economics. The sharp increase of environmental problems – extraordinary temperature changes, solar irradiation abnormalities, icy rains – raises the question of developing novel means of assessing and predicting potential UV effects. In this paper, we discuss new UV irradiation modeling based on recent real-time measurements at Moussala Basic Environmental Observatory (BEO) on Moussala Peak (2925 m ASL) in Rila Mountain, Bulgaria, and highlight the development and initial validation of portable embedded devices for UV-A, UV-B monitoring using open-source software architecture, narrow bandpass UV sensors, and the popular Arduino controllers. Despite the high temporal resolution of the VIS and UV irradiation measurements, the results obtained reveal the need of new assumptions in order to minimize the discrepancy with available databases.

  17. Theoretical model of two-phase drift flow on natural circulation

    International Nuclear Information System (INIS)

    Yang Xingtuan; Jiang Shengyao; Zhang Youjie

    2002-01-01

    Some expressions, such as sub-cooled boiling in the heating section, condensation near the riser inlet, flashing in the riser, and pressure balance in the steam-space, have been theoretically deduced from the physical model of 5 MW heating reactor test loop. The thermodynamics un-equilibrium etc have been considered too. A entire drift model with four equations has been formed, which can be applied to natural circulation system with low pressure and low steam quality. By means of introducing the concept of condensation layer, condensing of bubbles in the sub-cooled liquid has been formulated for the first time. The restrictive equations of the steam space pressure and liquid level have been offered. The equations can be solved by means of integral method, then by using Rung-Kutta-Verner method the final results is obtained

  18. Modeling of Hydrate Formation Mode in Raw Natural Gas Air Coolers

    Science.gov (United States)

    Scherbinin, S. V.; Prakhova, M. Yu; Krasnov, A. N.; Khoroshavina, E. A.

    2018-05-01

    Air cooling units (ACU) are used at all the gas fields for cooling natural gas after compressing. When using ACUs on raw (wet) gas in a low temperature condition, there is a danger of hydrate plug formation in the heat exchanging tubes of the ACU. To predict possible hydrate formation, a mathematical model of the air cooler thermal behavior used in the control system shall adequately calculate not only gas temperature at the cooler's outlet, but also a dew point value, a temperature at which condensation, as well as the gas hydrate formation point, onsets. This paper proposes a mathematical model allowing one to determine the pressure in the air cooler which makes hydrate formation for a given gas composition possible.

  19. Socio-economic vulnerability to natural hazards - proposal for an indicator-based model

    Science.gov (United States)

    Eidsvig, U.; McLean, A.; Vangelsten, B. V.; Kalsnes, B.; Ciurean, R. L.; Argyroudis, S.; Winter, M.; Corominas, J.; Mavrouli, O. C.; Fotopoulou, S.; Pitilakis, K.; Baills, A.; Malet, J. P.

    2012-04-01

    Vulnerability assessment, with respect to natural hazards, is a complex process that must consider multiple dimensions of vulnerability, including both physical and social factors. Physical vulnerability refers to conditions of physical assets, and may be modeled by the intensity and magnitude of the hazard, the degree of physical protection provided by the natural and built environment, and the physical robustness of the exposed elements. Social vulnerability refers to the underlying factors leading to the inability of people, organizations, and societies to withstand impacts from the natural hazards. Social vulnerability models can be used in combination with physical vulnerability models to estimate both direct losses, i.e. losses that occur during and immediately after the impact, as well as indirect losses, i.e. long-term effects of the event. Direct impact of a landslide typically includes casualties and damages to buildings and infrastructure while indirect losses may e.g. include business closures or limitations in public services. The direct losses are often assessed using physical vulnerability indicators (e.g. construction material, height of buildings), while indirect losses are mainly assessed using social indicators (e.g. economical resources, demographic conditions). Within the EC-FP7 SafeLand research project, an indicator-based method was proposed to assess relative socio-economic vulnerability to landslides. The indicators represent the underlying factors which influence a community's ability to prepare for, deal with, and recover from the damage associated with landslides. The proposed model includes indicators representing demographic, economic and social characteristics as well as indicators representing the degree of preparedness and recovery capacity. Although the model focuses primarily on the indirect losses, it could easily be extended to include more physical indicators which account for the direct losses. Each indicator is individually

  20. Multi-period natural gas market modeling Applications, stochastic extensions and solution approaches

    Science.gov (United States)

    Egging, Rudolf Gerardus

    This dissertation develops deterministic and stochastic multi-period mixed complementarity problems (MCP) for the global natural gas market, as well as solution approaches for large-scale stochastic MCP. The deterministic model is unique in the combination of the level of detail of the actors in the natural gas markets and the transport options, the detailed regional and global coverage, the multi-period approach with endogenous capacity expansions for transportation and storage infrastructure, the seasonal variation in demand and the representation of market power according to Nash-Cournot theory. The model is applied to several scenarios for the natural gas market that cover the formation of a cartel by the members of the Gas Exporting Countries Forum, a low availability of unconventional gas in the United States, and cost reductions in long-distance gas transportation. 1 The results provide insights in how different regions are affected by various developments, in terms of production, consumption, traded volumes, prices and profits of market participants. The stochastic MCP is developed and applied to a global natural gas market problem with four scenarios for a time horizon until 2050 with nineteen regions and containing 78,768 variables. The scenarios vary in the possibility of a gas market cartel formation and varying depletion rates of gas reserves in the major gas importing regions. Outcomes for hedging decisions of market participants show some significant shifts in the timing and location of infrastructure investments, thereby affecting local market situations. A first application of Benders decomposition (BD) is presented to solve a large-scale stochastic MCP for the global gas market with many hundreds of first-stage capacity expansion variables and market players exerting various levels of market power. The largest problem solved successfully using BD contained 47,373 variables of which 763 first-stage variables, however using BD did not result in

  1. Multi-Period Natural Gas Market Modeling. Applications, Stochastic Extensions and Solution Approaches

    International Nuclear Information System (INIS)

    Egging, R.G.

    2010-11-01

    This dissertation develops deterministic and stochastic multi-period mixed complementarity problems (MCP) for the global natural gas market, as well as solution approaches for large-scale stochastic MCP. The deterministic model is unique in the combination of the level of detail of the actors in the natural gas markets and the transport options, the detailed regional and global coverage, the multi-period approach with endogenous capacity expansions for transportation and storage infrastructure, the seasonal variation in demand and the representation of market power according to Nash-Cournot theory. The model is applied to several scenarios for the natural gas market that cover the formation of a cartel by the members of the Gas Exporting Countries Forum, a low availability of unconventional gas in the United States, and cost reductions in long-distance gas transportation. The results provide insights in how different regions are affected by various developments, in terms of production, consumption, traded volumes, prices and profits of market participants. The stochastic MCP is developed and applied to a global natural gas market problem with four scenarios for a time horizon until 2050 with nineteen regions and containing 78,768 variables. The scenarios vary in the possibility of a gas market cartel formation and varying depletion rates of gas reserves in the major gas importing regions. Outcomes for hedging decisions of market participants show some significant shifts in the timing and location of infrastructure investments, thereby affecting local market situations. A first application of Benders decomposition (BD) is presented to solve a large-scale stochastic MCP for the global gas market with many hundreds of first-stage capacity expansion variables and market players exerting various levels of market power. The largest problem solved successfully using BD contained 47,373 variables of which 763 first-stage variables, however using BD did not result in

  2. Is prostate cancer different in black men? Answers from 3 natural history models.

    Science.gov (United States)

    Tsodikov, Alex; Gulati, Roman; de Carvalho, Tiago M; Heijnsdijk, Eveline A M; Hunter-Merrill, Rachel A; Mariotto, Angela B; de Koning, Harry J; Etzioni, Ruth

    2017-06-15

    Black men in the United States have substantially higher prostate cancer incidence rates than the general population. The extent to which this incidence disparity is because prostate cancer is more prevalent, more aggressive, and/or more frequently diagnosed in black men is unknown. The authors estimated 3 independently developed models of prostate cancer natural history in black men and in the general population using an updated reconstruction of prostate-specific antigen screening, based on the National Health Interview Survey in 2005 and on prostate cancer incidence data from the Surveillance, Epidemiology, and End Results program during 1975 through 2000. By using the estimated models, the natural history of prostate cancer was compared between black men and the general population. The models projected that from 30% to 43% (range across models) of black men develop preclinical prostate cancer by age 85 years, a risk that is (relatively) 28% to 56% higher than that in the general population. Among men who had preclinical disease onset, black men had a similar risk of diagnosis (range, 35%-49%) compared with the general population (32%-44%), but their risk of progression to metastatic disease by the time of diagnosis was from 44% to 75% higher than that in the general population. Prostate cancer incidence patterns implicate higher incidence of preclinical disease and higher risk of metastatic progression among black men. The findings suggest screening black men earlier than white men and support further research into the benefit-harm tradeoffs of more aggressive screening policies for black men. Cancer 2017;123:2312-2319. © 2017 American Cancer Society. © 2017 American Cancer Society.

  3. Natural R parity conservation with horizontal symmetries: A four generation model

    International Nuclear Information System (INIS)

    Berezhiani, Z.; Nardi, E.

    1995-01-01

    In most supersymmetric models the stability of the proton is ensured by invoking R parity. A necessary ingredient to enforce R parity is the possibility of distinguishing the lepton superfields from the Higgs ones. This is generally achieved either by assuming different charges under some matter parity, or by assigning the superfields to different representations of a unified gauge group. We want to put forward the idea that the replica of the fermion generations, which constitute an intrinsic difference between the fermions and the Higgs superfields, can give a clue to understanding R parity as an accidental symmetry. More ambitiously, we suggest a possible relation between proton stability and the actual number of fermion generations. We carry out our investigation in the framework of non-Abelian horizontal gauge symmetries. We identify SU(4) H as the only acceptable horizontal gauge group which can naturally ensure the absence of R-parity-violating operators, without conflicting with other theoretical and phenomenological constraints. We analyze a version of the supersymmetric standard model equipped with a gauged horizontal SU(4) H , in which R parity is accidental. The model predicts four families of fermions, it allows for the dynamical generation of a realistic hierarchy of fermion masses without any ad hoc choice of small Yukawa couplings; it ensures in a natural way the heaviness of all the fourth family fermions (including the neutrino), and it predicts a lower limit for the τ-neutrino mass of a few eV. The scale of the breaking of the horizontal symmetry can be constrained rather precisely in a narrow window around ∼10 11 GeV. Some interesting astrophysical and cosmological implications of the model are addressed as well

  4. Chromium (VI) reduction in acetate- and molasses-amended natural media: empirical model development

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Dongping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vesselinov, Velimir Valentinov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-21

    Stimulating indigenous microbes to reduce heavy metals from highly toxic oxidized species to more benign reduced species is a promising groundwater remediation technique that has already seen successful field applications. Designing such a bio-remediation scheme requires a model incorporating the kinetics of nonlinear bio-geochemical interactions between multiple species. With this motivation, we performed a set of microcosm experiments in natural sediments and their indigenous pore water and microbes, generating simultaneous time series for concentrations of Cr(VI), an electron donor (both molasses and acetate were considered), and biomass. Molasses was found to undergo a rapid direct abiotic reaction which eliminated all Cr(VI) before any biomass had time to grow. This was not found in the acetate microcosms, and a distinct zero-order bio-reduction process was observed. Existing models were found inappropriate and a new set of three coupled governing equations representing these process dynamics were developed and their parameters calibrated against the time series from the acetate-amended microcosms. Cell suspension batch experiments were also performed to calibrate bio-reduction rates in the absence of electron donor and sediment. The donor used to initially grow the cells (molasses or acetate) was found not to impact the reduction rate constants in suspension, which were orders of magnitude larger than those explaining the natural media microcosm experiments. This suggests the limited utility of kinetics determined in suspension for remedial design. Scoping studies on the natural media microcosms were also performed, suggesting limited impact of foreign abiotic material and minimal effect of diffusion limitation in the vertical dimension. These analyses may be of independent value to future researchers.

  5. Modelling the stochastic nature of the available coefficient of friction at footwear-floor interfaces.

    Science.gov (United States)

    Gragg, Jared; Klose, Ellison; Yang, James

    2017-07-01

    The available coefficient of friction (ACOF) is a measure of the friction available between two surfaces, which for human gait would be the footwear-floor interface. It is often compared to the required coefficient of friction (RCOF) to determine the likelihood of a slip in gait. Both the ACOF and RCOF are stochastic by nature meaning that neither should be represented by a deterministic value, such as the sample mean. Previous research has determined that the RCOF can be modelled well by either the normal or lognormal distributions, but previous research aimed at determining an appropriate distribution for the ACOF was inconclusive. This study focuses on modelling the stochastic nature of the ACOF by fitting eight continuous probability distributions to ACOF data for six scenarios. In addition, the data were used to study the effect that a simple housekeeping action such as sweeping could have on the ACOF. Practitioner Summary: Previous research aimed at determining an appropriate distribution for the ACOF was inconclusive. The study addresses this issue as well as looking at the effect that an act such as sweeping has on the ACOF.

  6. An evaluation of Substitute natural gas production from different coal gasification processes based on modeling

    International Nuclear Information System (INIS)

    Karellas, S.; Panopoulos, K.D.; Panousis, G.; Rigas, A.; Karl, J.; Kakaras, E.

    2012-01-01

    Coal and lignite will play a significant role in the future energy production. However, the technical options for the reduction of CO 2 emissions will define the extent of their share in the future energy mix. The production of synthetic or substitute natural gas (SNG) from solid fossil fuels seems to be a very attractive process: coal and lignite can be upgraded into a methane rich gas which can be transported and further used in high efficient power systems coupled with CO 2 sequestration technologies. The aim of this paper is to present a modeling analysis comparison between substitute natural gas production from coal by means of allothermal steam gasification and autothermal oxygen gasification. In order to produce SNG from syngas several unit operations are required such as syngas cooling, cleaning, potential compression and, of course, methanation reactors. Finally the gas which is produced has to be conditioned i.e. removal of unwanted species, such as CO 2 etc. The heat recovered from the overall process is utilized by a steam cycle, producing power. These processes were modeled with the computer software IPSEpro™. An energetic and exergetic analysis of the coal to SNG processes have been realized and compared. -- Highlights: ► The production of SNG from coal is examined. ► The components of the process were simulated for integrated autothermal or allothermal coal gasification to SNG. ► The energetic and exergetic evaluation of the two processes is presented.

  7. Remediation of a historically Pb contaminated soil using a model natural Mn oxide waste.

    Science.gov (United States)

    McCann, Clare M; Gray, Neil D; Tourney, Janette; Davenport, Russell J; Wade, Matthew; Finlay, Nina; Hudson-Edwards, Karen A; Johnson, Karen L

    2015-11-01

    A natural Mn oxide (NMO) waste was assessed as an in situ remediation amendment for Pb contaminated sites. The viability of this was investigated using a 10 month lysimeter trial, wherein a historically Pb contaminated soil was amended with a 10% by weight model NMO. The model NMO was found to have a large Pb adsorption capacity (qmax 346±14 mg g(-1)). However, due to the heterogeneous nature of the Pb contamination in the soils (3650.54-9299.79 mg kg(-1)), no treatment related difference in Pb via geochemistry could be detected. To overcome difficulties in traditional geochemical techniques due to pollutant heterogeneity we present a new method for unequivocally proving metal sorption to in situ remediation amendments. The method combines two spectroscopic techniques; namely electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). Using this we showed Pb immobilisation on NMO, which were Pb free prior to their addition to the soils. Amendment of the soil with exogenous Mn oxide had no effect on microbial functioning, nor did it perturb the composition of the dominant phyla. We conclude that NMOs show excellent potential as remediation amendments. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Detection of Natural Fractures from Observed Surface Seismic Data Based on a Linear-Slip Model

    Science.gov (United States)

    Chen, Huaizhen; Zhang, Guangzhi

    2018-03-01

    Natural fractures play an important role in migration of hydrocarbon fluids. Based on a rock physics effective model, the linear-slip model, which defines fracture parameters (fracture compliances) for quantitatively characterizing the effects of fractures on rock total compliance, we propose a method to detect natural fractures from observed seismic data via inversion for the fracture compliances. We first derive an approximate PP-wave reflection coefficient in terms of fracture compliances. Using the approximate reflection coefficient, we derive azimuthal elastic impedance as a function of fracture compliances. An inversion method to estimate fracture compliances from seismic data is presented based on a Bayesian framework and azimuthal elastic impedance, which is implemented in a two-step procedure: a least-squares inversion for azimuthal elastic impedance and an iterative inversion for fracture compliances. We apply the inversion method to synthetic and real data to verify its stability and reasonability. Synthetic tests confirm that the method can make a stable estimation of fracture compliances in the case of seismic data containing a moderate signal-to-noise ratio for Gaussian noise, and the test on real data reveals that reasonable fracture compliances are obtained using the proposed method.

  9. Model Based Analysis of Forced and Natural Convection Effects in an Electrochemical Cell

    Directory of Open Access Journals (Sweden)

    D Brunner

    2017-03-01

    Full Text Available High purity copper, suitable for electrical applications, can only be obtained by electro-winning. The hallmark of this process is its self-induced natural convection through density variations of the electrolyte at both anode and cathode. In order to do this, first the full dynamic complexity of the process needs to be understood. Thus an OpenFoam®-based 2D model of the process has been created. This finite-volume multiphysics approach solves the laminar momentum and copper-ion species conservation equations, as well as local copper-ion conversion kinetics. It uses a Boussinesq approximation to simulate the species-momentum coupling, namely natural draft forces induced by variations of the spatial copper concentration within the fluid. The model shows good agreement with benchmark-cases of real-life electrochemical cells found in literature. An additional flow was imposed at the bottom of a small scale electrochemical cell in order to increase the ionic transport and thereby increase the overall performance of the cell. In a small scale electrochemical cell in strictly laminar flow, the overall performance could be increased and stratification decreased.

  10. 75 FR 53371 - Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas Dispersion Models

    Science.gov (United States)

    2010-08-31

    .... PHMSA-2010-0226] Liquefied Natural Gas Facilities: Obtaining Approval of Alternative Vapor-Gas... safety standards for siting liquefied natural gas (LNG) facilities. Those standards require that an..., and Handling of Liquefied Natural Gas. That consensus [[Page 53372

  11. Risk Analysis on Leakage Failure of Natural Gas Pipelines by Fuzzy Bayesian Network with a Bow-Tie Model

    OpenAIRE

    Shan, Xian; Liu, Kang; Sun, Pei-Liang

    2017-01-01

    Pipeline is the major mode of natural gas transportation. Leakage of natural gas pipelines may cause explosions and fires, resulting in casualties, environmental damage, and material loss. Efficient risk analysis is of great significance for preventing and mitigating such potential accidents. The objective of this study is to present a practical risk assessment method based on Bow-tie model and Bayesian network for risk analysis of natural gas pipeline leakage. Firstly, identify the potential...

  12. Modeling the effect of the inclination angle on natural convection from a flat plate: The case of a photovoltaic module

    OpenAIRE

    Perović Bojan D.; Klimenta Jelena Lj.; Tasić Dragan S.; Peuteman Joan L.G.; Klimenta Dardan O.; Anđelković Ljiljana N.

    2017-01-01

    The main purpose of this paper is to show how the inclination angle affects natural convection from a flat-plate photovoltaic module which is mounted on the ground surface. In order to model this effect, novel correlations for natural convection from isothermal flat plates are developed by using the fundamental dimensionless number. On the basis of the available experimental and numerical results, it is shown that the natural convection correlations correspond well with the existing empirical...

  13. A generalized linear model for estimating spectrotemporal receptive fields from responses to natural sounds.

    Directory of Open Access Journals (Sweden)

    Ana Calabrese

    2011-01-01

    Full Text Available In the auditory system, the stimulus-response properties of single neurons are often described in terms of the spectrotemporal receptive field (STRF, a linear kernel relating the spectrogram of the sound stimulus to the instantaneous firing rate of the neuron. Several algorithms have been used to estimate STRFs from responses to natural stimuli; these algorithms differ in their functional models, cost functions, and regularization methods. Here, we characterize the stimulus-response function of auditory neurons using a generalized linear model (GLM. In this model, each cell's input is described by: 1 a stimulus filter (STRF; and 2 a post-spike filter, which captures dependencies on the neuron's spiking history. The output of the model is given by a series of spike trains rather than instantaneous firing rate, allowing the prediction of spike train responses to novel stimuli. We fit the model by maximum penalized likelihood to the spiking activity of zebra finch auditory midbrain neurons in response to conspecific vocalizations (songs and modulation limited (ml noise. We compare this model to normalized reverse correlation (NRC, the traditional method for STRF estimation, in terms of predictive power and the basic tuning properties of the estimated STRFs. We find that a GLM with a sparse prior predicts novel responses to both stimulus classes significantly better than NRC. Importantly, we find that STRFs from the two models derived from the same responses can differ substantially and that GLM STRFs are more consistent between stimulus classes than NRC STRFs. These results suggest that a GLM with a sparse prior provides a more accurate characterization of spectrotemporal tuning than does the NRC method when responses to complex sounds are studied in these neurons.

  14. Modeling natural wetlands: A new global framework built on wetland observations

    Science.gov (United States)

    Matthews, E.; Romanski, J.; Olefeldt, D.

    2015-12-01

    Natural wetlands are the world's largest methane (CH4) source, and their distribution and CH4 fluxes are sensitive to interannual and longer-term climate variations. Wetland distributions used in wetland-CH4 models diverge widely, and these geographic differences contribute substantially to large variations in magnitude, seasonality and distribution of modeled methane fluxes. Modeling wetland type and distribution—closely tied to simulating CH4 emissions—is a high priority, particularly for studies of wetlands and CH4 dynamics under past and future climates. Methane-wetland models either prescribe or simulate methane-producing areas (aka wetlands) and both approaches result in predictable over- and under-estimates. 1) Monthly satellite-derived inundation data include flooded areas that are not wetlands (e.g., lakes, reservoirs, and rivers), and do not identify non-flooded wetlands. 2) Models simulating methane-producing areas overwhelmingly rely on modeled soil moisture, systematically over-estimating total global area, with regional over- and under-estimates, while schemes to model soil-moisture typically cannot account for positive water tables (i.e., flooding). Interestingly, while these distinct hydrological approaches to identify wetlands are complementary, merging them does not provide critical data needed to model wetlands for methane studies. We present a new integrated framework for modeling wetlands, and ultimately their methane emissions, that exploits the extensive body of data and information on wetlands. The foundation of the approach is an existing global gridded data set comprising all and only wetlands, including vegetation information. This data set is augmented with data inter alia on climate, inundation dynamics, soil type and soil carbon, permafrost, active-layer depth, growth form, and species composition. We investigate this enhanced wetland data set to identify which variables best explain occurrence and characteristics of observed

  15. Hydrophysical conditions and periphyton in natural rivers. Analysis and predictive modelling of periphyton by changed regulations

    International Nuclear Information System (INIS)

    Stokseth, S.

    1994-10-01

    The objective of this thesis has been to examine the interaction between hydrodynamical and physical factors and the temporal and spatial dynamics of periphyton in natural steep rivers. The study strategy has been to work with quantitative system variables to be able to evaluate the potential usability of a predictive model for periphyton changes as a response to river regulations. The thesis is constituted by a theoretical and an empirical study. The theoretical study is aimed at presenting a conceptual model of the relevant factors based on an analysis of published studies. Effort has been made to evaluate and present the background material in a structured way. To concurrently handle the spatial and temporal dynamics of periphyton a new method for data collection has been developed. A procedure for quantifying the photo registrations has been developed. The simple hydrodynamical parameters were estimated from a set of standard formulas whereas the complex parameters were estimated from a three dimensional simulation model called SSIIM. The main conclusion from the analysis is that flood events are the major controlling factors wrt. periphyton biomass and that water temperature is of major importance for the periphyton resistance. Low temperature clearly increases the periphyton erosion resistance. Thus, to model or control the temporal dynamics the river periphyton, the water temperature and the frequency and size of floods should be regarded the most significant controlling factors. The data in this study has been collected from a river with a stable water quality and frequent floods. 109 refs., 41 figs., 34 tabs

  16. XFEM modeling of hydraulic fracture in porous rocks with natural fractures

    Science.gov (United States)

    Wang, Tao; Liu, ZhanLi; Zeng, QingLei; Gao, Yue; Zhuang, Zhuo

    2017-08-01

    Hydraulic fracture (HF) in porous rocks is a complex multi-physics coupling process which involves fluid flow, diffusion and solid deformation. In this paper, the extended finite element method (XFEM) coupling with Biot theory is developed to study the HF in permeable rocks with natural fractures (NFs). In the recent XFEM based computational HF models, the fluid flow in fractures and interstitials of the porous media are mostly solved separately, which brings difficulties in dealing with complex fracture morphology. In our new model the fluid flow is solved in a unified framework by considering the fractures as a kind of special porous media and introducing Poiseuille-type flow inside them instead of Darcy-type flow. The most advantage is that it is very convenient to deal with fluid flow inside the complex fracture network, which is important in shale gas extraction. The weak formulation for the new coupled model is derived based on virtual work principle, which includes the XFEM formulation for multiple fractures and fractures intersection in porous media and finite element formulation for the unified fluid flow. Then the plane strain Kristianovic-Geertsma-de Klerk (KGD) model and the fluid flow inside the fracture network are simulated to validate the accuracy and applicability of this method. The numerical results show that large injection rate, low rock permeability and isotropic in-situ stresses tend to lead to a more uniform and productive fracture network.

  17. On the Flavor Structure of Natural Composite Higgs Models & Top Flavor Violation

    CERN Document Server

    Azatov, Aleksandr; Perez, Gilad; Soreq, Yotam

    2014-01-01

    We explore the up flavor structure of composite pseudo Nambu-Goldstone-boson Higgs models, where we focus on the flavor anarchic minimal $SO(5)$ case. We identify the different sources of flavor violation in this framework and emphasise the differences from the anarchic Randall-Sundrum scenario. In particular, the fact that the flavor symmetry does not commute with the symmetries that stabilize the Higgs potential may constrain the flavor structure of the theory. In addition, we consider the interplay between the fine tuning of the model and flavor violation. We find that generically the tuning of this class of models is worsen in the anarchic case due to the contributions from the additional fermion resonances. We show that, even in the presence of custodial symmetry, large top flavor violating rate are naturally expected. In particular, $t\\to cZ$ branching ratio of order of $10^{-5}$ is generic for this class of models. Thus, this framework can be tested in the next run of the LHC as well as in other future...

  18. On the nature of the sea ice albedo feedback in simple models.

    Science.gov (United States)

    Moon, W; Wettlaufer, J S

    2014-08-01

    We examine the nature of the ice-albedo feedback in a long-standing approach used in the dynamic-thermodynamic modeling of sea ice. The central issue examined is how the evolution of the ice area is treated when modeling a partial ice cover using a two-category-thickness scheme; thin sea ice and open water in one category and "thick" sea ice in the second. The problem with the scheme is that the area evolution is handled in a manner that violates the basic rules of calculus, which leads to a neglected area evolution term that is equivalent to neglecting a leading-order latent heat flux. We demonstrate the consequences by constructing energy balance models with a fractional ice cover and studying them under the influence of increased radiative forcing. It is shown that the neglected flux is particularly important in a decaying ice cover approaching the transitions to seasonal or ice-free conditions. Clearly, a mishandling of the evolution of the ice area has leading-order effects on the ice-albedo feedback. Accordingly, it may be of considerable importance to reexamine the relevant climate model schemes and to begin the process of converting them to fully resolve the sea ice thickness distribution in a manner such as remapping, which does not in principle suffer from the pathology we describe.

  19. Natural and molecular history of prolactinoma: insights from a Prlr-/- mouse model.

    Science.gov (United States)

    Bernard, Valérie; Villa, Chiara; Auguste, Aurélie; Lamothe, Sophie; Guillou, Anne; Martin, Agnès; Caburet, Sandrine; Young, Jacques; Veitia, Reiner A; Binart, Nadine

    2018-01-19

    Lactotroph adenoma, also called prolactinoma, is the most common pituitary tumor but little is known about its pathogenesis. Mouse models of prolactinoma can be useful to better understand molecular mechanisms involved in abnormal lactotroph cell proliferation and secretion. We have previously developed a prolactin receptor deficient ( Prlr -/- ) mouse, which develops prolactinoma. The present study aims to explore the natural history of prolactinoma formation in Prlr -/- mice, using hormonal, radiological, histological and molecular analyses to uncover mechanisms involved in lactotroph adenoma development. Prlr -/- females develop large secreting prolactinomas from 12 months of age, with a penetrance of 100%, mimicking human aggressive densely granulated macroprolactinoma, which is a highly secreting subtype. Mean blood PRL measurements reach 14 902 ng/mL at 24 months in Prlr -/- females while PRL levels were below 15 ng/mL in control mice ( p model in ACI rats, we pinpointed 218 concordantly differentially expressed (DE) genes involved in cell cycle, mitosis, cell adhesion molecules, dopaminergic synapse and estrogen signaling. Pathway/gene-set enrichment analyses suggest that the transcriptomic dysregulation in both models of prolactinoma might be mediated by a limited set of transcription factors (i.e., STAT5, STAT3, AhR, ESR1, BRD4, CEBPD, YAP, FOXO1) and kinases (i.e., JAK2, AKT1, BRAF, BMPR1A, CDK8, HUNK, ALK, FGFR1, ILK). Our experimental results and their bioinformatic analysis provide insights into early genomic changes in murine models of the most frequent human pituitary tumor.

  20. Higgs boson couplings in multi-doublet models with natural flavour conservation

    Directory of Open Access Journals (Sweden)

    Kei Yagyu

    2016-12-01

    Full Text Available We investigate the deviation in the couplings of the standard model (SM like Higgs boson (h with a mass of 125 GeV from the prediction of the SM in multi-doublet models within the framework where flavour changing neutral currents at the tree level are naturally forbidden. After we present the general expressions for the modified gauge and Yukawa couplings for h, we show the correlation between the deviation in the Yukawa coupling for the tau lepton hτ+τ− and that for the bottom quark hbb¯ under the assumption of a non-zero deviation in the hVV (V=W,Z couplings in two Higgs doublet models (2HDMs and three Higgs doublet models (3HDMs as simple examples. We clarify the possible allowed prediction of the deviations in the 3HDMs which cannot be explained in the 2HDMs even taking into account the one-loop electroweak corrections to the Yukawa coupling.

  1. Nature of phase transitions in Axelrod-like coupled Potts models in two dimensions

    Science.gov (United States)

    Gandica, Yerali; Chiacchiera, Silvia

    2016-03-01

    We study F coupled q -state Potts models in a two-dimensional square lattice. The interaction between the different layers is attractive to favor a simultaneous alignment in all of them, and its strength is fixed. The nature of the phase transition for zero field is numerically determined for F =2 ,3 . Using the Lee-Kosterlitz method, we find that it is continuous for F =2 and q =2 , whereas it is abrupt for higher values of q and/or F . When a continuous or a weakly first-order phase transition takes place, we also analyze the properties of the geometrical clusters. This allows us to determine the fractal dimension D of the incipient infinite cluster and to examine the finite-size scaling of the cluster number density via data collapse. A mean-field approximation of the model, from which some general trends can be determined, is presented too. Finally, since this lattice model has been recently considered as a thermodynamic counterpart of the Axelrod model of social dynamics, we discuss our results in connection with this one.

  2. Modelling nitrogen and carbon interactions in composting of animal manure in naturally aerated piles.

    Science.gov (United States)

    Oudart, D; Robin, P; Paillat, J M; Paul, E

    2015-12-01

    Composting animal manure with natural aeration is a low-cost and low-energy process that can improve nitrogen recycling in millions of farms world-wide. Modelling can decrease the cost of choosing the best options for solid manure management in order to decrease the risk of loss of fertilizer value and ammonia emission. Semi-empirical models are suitable, considering the scarce data available in farm situations. Eleven static piles of pig or poultry manure were monitored to identify the main processes governing nitrogen transformations and losses. A new model was implemented to represent these processes in a pile considered as homogeneous. The model is based on four modules: biodegradation, nitrogen transformations and volatilization, thermal exchanges, and free air space evolution. When necessary, the parameters were calibrated with the data set. The results showed that microbial growth could reduce ammonia volatilization. Greatest nitrogen conservation is achieved when microbial growth was limited by nitrogen availability. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. New prognostic model for extranodal natural killer/T cell lymphoma, nasal type.

    Science.gov (United States)

    Cai, Qingqing; Luo, Xiaolin; Zhang, Guanrong; Huang, Huiqiang; Huang, Hui; Lin, Tongyu; Jiang, Wenqi; Xia, Zhongjun; Young, Ken H

    2014-09-01

    Extranodal natural killer/T cell lymphoma, nasal type (ENKTL) is an aggressive disease with a poor prognosis, requiring risk stratification in affected patients. We designed a new prognostic model specifically for ENKTL to identify high-risk patients who need more aggressive therapy. We retrospectively reviewed 158 patients who were newly diagnosed with ENKTL. The estimated 5-year overall survival rate was 39.4 %. Independent prognostic factors included total protein (TP) 100 mg/dL, and Korean Prognostic Index (KPI) score ≥2. We constructed a new prognostic model by combining these prognostic factors: group 1 (64 cases (41.0 %)), no adverse factors; group 2 (58 cases (37.2 %)), one adverse factor; and group 3 (34 cases (21.8 %)), two or three adverse factors. The 5-year overall survival (OS) rates of these groups were 66.7, 23.0, and 5.9 %, respectively (p KPI model alone (p KPI model alone.

  4. Modeling silviculture after natural disturbance to sustain biodiversity in the longleaf pine (Pinus palustris) ecosystem : balancing complexity and implementation

    Science.gov (United States)

    Brian J. Palik; Robert J. Mitchell; J. Kevin Hiers

    2002-01-01

    Modeling silviculture after natural disturbance to maintain biodiversity is a popular concept, yet its application remains elusive. We discuss difficulties inherent to this idea, and suggest approaches to facilitate implementation, using longleaf pine (Pinus palustris) as an example. Natural disturbance regimes are spatially and temporally variable. Variability...

  5. Analysis of Water Conflicts across Natural and Societal Boundaries: Integration of Quantitative Modeling and Qualitative Reasoning

    Science.gov (United States)

    Gao, Y.; Balaram, P.; Islam, S.

    2009-12-01

    Water issues and problems have bewildered humankind for a long time yet a systematic approach for understanding such issues remain elusive. This is partly because many water-related problems are framed from a contested terrain in which many actors (individuals, communities, businesses, NGOs, states, and countries) compete to protect their own and often conflicting interests. We argue that origin of many water problems may be understood as a dynamic consequence of competition, interconnections, and feedback among variables in the Natural and Societal Systems (NSSs). Within the natural system, we recognize that triple constraints on water- water quantity (Q), water quality (P), and ecosystem (E)- and their interdependencies and feedback may lead to conflicts. Such inherent and multifaceted constraints of the natural water system are exacerbated often at the societal boundaries. Within the societal system, interdependencies and feedback among values and norms (V), economy (C), and governance (G) interact in various ways to create intractable contextual differences. The observation that natural and societal systems are linked is not novel. Our argument here, however, is that rigid disciplinary boundaries between these two domains will not produce solutions to the water problems we are facing today. The knowledge needed to address water problems need to go beyond scientific assessment in which societal variables (C, G, and V) are treated as exogenous or largely ignored, and policy research that does not consider the impact of natural variables (E, P, and Q) and that coupling among them. Consequently, traditional quantitative methods alone are not appropriate to address the dynamics of water conflicts, because we cannot quantify the societal variables and the exact mathematical relationships among the variables are not fully known. On the other hand, conventional qualitative study in societal domain has mainly been in the form of individual case studies and therefore

  6. Numerical modeling of supercritical CO{sub 2} natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Archana, V., E-mail: archanav@barc.gov.in [Homi Bhabha National Institute, Mumbai, Maharashtra 400 094 (India); Vaidya, A.M., E-mail: avaidya@barc.gov.in [Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Vijayan, P.K., E-mail: vijayanp@barc.gov.in [Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India)

    2015-11-15

    Highlights: • Supercritical CO{sub 2} natural circulation loop is modeled by in-house developed 1D and 2D axi-symmetric CFD codes. • Steady state characteristics of VHVC configuration of supercritical CO{sub 2} natural circulation loop are studied over a range of power. • Improved accuracy of predictions by 2D axi-symmetric formulation over 1D formulation is demonstrated. • The validity of correlations used in 1D model such as friction factor and heat transfer correlations is analyzed. • Simulation results shows normal, enhanced and deteriorated heat transfer regimes in supercritical CO{sub 2} natural circulation loop. - Abstract: The objective of this research project is to estimate steady state characteristics of supercritical natural circulation loop (SCNCL) using computational methodology and to compliment on-going experimental investigation of the same at the authors’ organization. For computational investigation, a couple of in-house codes are developed. At first, formulation and a corresponding computer program for the SCNCL based on conservation equations written in 1D framework is developed. Comparison of 1D code results with experimental data showed that, under some operating conditions, there is deviation between computed results and experimental data. To improve predictive capability, it was thought to model the SCNCL using conservation equations in 2D axi-symmetric framework. An existing 2D axi-symmetric code (named NAFA), which was developed and validated for supercritical fluid flow in pipes, is modified for natural circulation loop (NCL) geometry. The modified code, named NAFA-Loop, is subsequently used to compute the steady state characteristics of the SCNCL. These results are compared with experimental data. The steady state characteristics such as the variation of mass flow rate with power, velocity and temperature profiles in heater and cooler are studied using NAFA-Loop. The computed velocity and temperature fields show that the

  7. The Employment of spatial autoregressive models in predicting demand for natural gas; O Emprego de modelos auto-regressivos espaciais na previsao de demanda para gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Jorge Henrique de [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Silva, Alexandre Pinto Alves da [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Eletrica

    2010-07-01

    Develop the natural gas network is critical success factor for the distribution company. It is a decision that employs the demand given location 'x' and a future time 't' so that the net allows the best conditions for the return of the capital. In this segment, typical network industry, the spatial infra-structure vision associated to the market allows better evaluation of the business because to mitigate costs and risks. In fact, economic models little developed in order to assess the question of the location, due to its little employment by economists. The objective of this article is to analyze the application of spatial perspective in natural gas demand forecasting and to identify the models that can be employed observing issues of dependency and spatial heterogeneity; as well as the capacity of mapping of variables associated with the problem. (author)

  8. Homology modelling and docking studies on Neuraminidase enzyme as a natural product target for combating influenza

    Directory of Open Access Journals (Sweden)

    Nisha Singh

    2017-10-01

    Full Text Available Influenza remains to be dreadful with yearly epidemics and sudden pandemic outbreaks causing significant mortality, even in nations with the most advanced health care systems. Thus, there has been a long-standing interest to develop effective and safe antiviral agents to treat infected individuals. Attempt to identify suitable molecular targets as antiviral compounds have focused recently on the influenza virus neuraminidase (NA, a key enzyme in viral replication [1]. In this research, virtual screening was done on a total of 600 natural compounds from 22 ethno medicinal Indian herbs for activity against neuraminidase enzyme exploiting representative protein conformations selected from molecular dynamics simulations. Neuraminidase enzyme sequences from different existing strains available on National Center of Biotechnology Information [2] (NCBI protein database were aligned using Clustal W [3] and CLC workbench 10 [4] to find the conserved residues. Neuraminidase protein sequence from H1N1 strain available on NCBI was used to structure 3D target model predicted against dataset from Protein data bank using modeller [5]. The target model was validated on different parameter at SAVES Server [6]. Using this target model a pharmacophore model was developed using ligand based strategy exploiting the three known inhibitors. The docking parameters were validated by redocking Zanamivir to its co-complex 2009 H1N1 NA crystal structure (PDB ID: 3TI5 generating best pose with a RMSD value of 0.7543 A°. This model was then used for in silico analysis of a library of natural compounds from 22 ethno medicinal Indian herbs known to have antiviral activity taken downloaded from PubChem database and selected on the basis of drug likeliness. All the compounds were docked in the binding pocket of neuraminidase. Top compounds having binding affinity better than or comparable to the control drug Zanamivir were selected and analyzed for their ADME and toxicity

  9. The field experiments and model of the natural dust deposition effects on photovoltaic module efficiency.

    Science.gov (United States)

    Jaszczur, Marek; Teneta, Janusz; Styszko, Katarzyna; Hassan, Qusay; Burzyńska, Paulina; Marcinek, Ewelina; Łopian, Natalia

    2018-04-20

    The maximisation of the efficiency of the photovoltaic system is crucial in order to increase the competitiveness of this technology. Unfortunately, several environmental factors in addition to many alterable and unalterable factors can significantly influence the performance of the PV system. Some of the environmental factors that depend on the site have to do with dust, soiling and pollutants. In this study conducted in the city centre of Kraków, Poland, characterised by high pollution and low wind speed, the focus is on the evaluation of the degradation of efficiency of polycrystalline photovoltaic modules due to natural dust deposition. The experimental results that were obtained demonstrated that deposited dust-related efficiency loss gradually increased with the mass and that it follows the exponential. The maximum dust deposition density observed for rainless exposure periods of 1 week exceeds 300 mg/m 2 and the results in efficiency loss were about 2.1%. It was observed that efficiency loss is not only mass-dependent but that it also depends on the dust properties. The small positive effect of the tiny dust layer which slightly increases in surface roughness on the module performance was also observed. The results that were obtained enable the development of a reliable model for the degradation of the efficiency of the PV module caused by dust deposition. The novelty consists in the model, which is easy to apply and which is dependent on the dust mass, for low and moderate naturally deposited dust concentration (up to 1 and 5 g/m 2 and representative for many geographical regions) and which is applicable to the majority of cases met in an urban and non-urban polluted area can be used to evaluate the dust deposition-related derating factor (efficiency loss), which is very much sought after by the system designers, and tools used for computer modelling and system malfunction detection.

  10. Experimentally Identify the Effective Plume Chimney over a Natural Draft Chimney Model

    Science.gov (United States)

    Rahman, M. M.; Chu, C. M.; Tahir, A. M.; Ismail, M. A. bin; Misran, M. S. bin; Ling, L. S.

    2017-07-01

    The demands of energy are in increasing order due to rapid industrialization and urbanization. The researchers and scientists are working hard to improve the performance of the industry so that the energy consumption can be reduced significantly. Industries like power plant, timber processing plant, oil refinery, etc. performance mainly depend on the cooling tower chimney’s performance, either natural draft or forced draft. Chimney is used to create sufficient draft, so that air can flow through it. Cold inflow or flow reversal at chimney exit is one of the main identified problems that may alter the overall plant performance. The presence Effective Plume Chimney (EPC) is an indication of cold inflow free operation of natural draft chimney. Different mathematical model equations are used to estimate the EPC height over the heat exchanger or hot surface. In this paper, it is aim to identify the EPC experimentally. In order to do that, horizontal temperature profiling is done at the exit of the chimneys of face area 0.56m2, 1.00m2 and 2.25m2. A wire mesh screen is installed at chimneys exit to ensure cold inflow chimney operation. It is found that EPC exists in all modified chimney models and the heights of EPC varied from 1 cm to 9 cm. The mathematical models indicate that the estimated heights of EPC varied from 1 cm to 2.3 cm. Smoke test is also conducted to ensure the existence of EPC and cold inflow free option of chimney. Smoke test results confirmed the presence of EPC and cold inflow free operation of chimney. The performance of the cold inflow free chimney is increased by 50% to 90% than normal chimney.

  11. Instrumental record of debris flow initiation during natural rainfall: Implications for modeling slope stability

    Science.gov (United States)

    Montgomery, D.R.; Schmidt, K.M.; Dietrich, W.E.; McKean, J.

    2009-01-01

    The middle of a hillslope hollow in the Oregon Coast Range failed and mobilized as a debris flow during heavy rainfall in November 1996. Automated pressure transducers recorded high spatial variability of pore water pressure within the area that mobilized as a debris flow, which initiated where local upward flow from bedrock developed into overlying colluvium. Postfailure observations of the bedrock surface exposed in the debris flow scar reveal a strong spatial correspondence between elevated piezometric response and water discharging from bedrock fractures. Measurements of apparent root cohesion on the basal (Cb) and lateral (Cl) scarp demonstrate substantial local variability, with areally weighted values of Cb = 0.1 and Cl = 4.6 kPa. Using measured soil properties and basal root strength, the widely used infinite slope model, employed assuming slope parallel groundwater flow, provides a poor prediction of hydrologie conditions at failure. In contrast, a model including lateral root strength (but neglecting lateral frictional strength) gave a predicted critical value of relative soil saturation that fell within the range defined by the arithmetic and geometric mean values at the time of failure. The 3-D slope stability model CLARA-W, used with locally observed pore water pressure, predicted small areas with lower factors of safety within the overall slide mass at sites consistent with field observations of where the failure initiated. This highly variable and localized nature of small areas of high pore pressure that can trigger slope failure means, however, that substantial uncertainty appears inevitable for estimating hydrologie conditions within incipient debris flows under natural conditions. Copyright 2009 by the American Geophysical Union.

  12. Inspiration from nature: dynamic modelling of the musculoskeletal structure of the seahorse tail.

    Science.gov (United States)

    Praet, Tomas; Adriaens, Dominique; Van Cauter, Sofie; Masschaele, Bert; De Beule, Matthieu; Verhegghe, Benedict

    2012-10-01

    Technological advances are often inspired by nature, considering that engineering is frequently faced by the same challenges as organisms in nature. One such interesting challenge is creating a structure that is at the same time stiff in a certain direction, yet flexible in another. The seahorse tail combines both radial stiffness and bending flexibility in a particularly elegant way: even though the tail is covered in a protective armour, it still shows sufficient flexibility to fully function as a prehensile organ. We therefore study the complex mechanics and dynamics of the musculoskeletal system of the seahorse tail from an engineering point of view. The seahorse tail derives its combination of flexibility and resilience from a chain of articulating skeletal segments. A versatile dynamic model of those segments was constructed, on the basis of automatic recognition of joint positions and muscle attachments. Both muscle structures that are thought to be responsible for ventral and ventral-lateral tail bending, namely the median ventral muscles and the hypaxial myomere muscles, were included in the model. Simulations on the model consist mainly of dynamic multi-body simulations. The results show that the sequential structure of uniformly shaped bony segments can remain flexible because of gliding joints that connect the corners of the segments. Radial stiffness on the other hand is obtained through the support that the central vertebra provides to the tail plating. Such insights could help in designing biomedical instruments that specifically require both high bending flexibility and radial stiffness (e.g. flexible stents and steerable catheters). Copyright © 2012 John Wiley & Sons, Ltd.

  13. Integrating social science into empirical models of coupled human and natural systems

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Kline

    2017-09-01

    Full Text Available Coupled human and natural systems (CHANS research highlights reciprocal interactions (or feedbacks between biophysical and socioeconomic variables to explain system dynamics and resilience. Empirical models often are used to test hypotheses and apply theory that represent human behavior. Parameterizing reciprocal interactions presents two challenges for social scientists: (1 how to represent human behavior as influenced by biophysical factors and integrate this into CHANS empirical models; (2 how to organize and function as a multidisciplinary social science team to accomplish that task. We reflect on these challenges regarding our CHANS research that investigated human adaptation to fire-prone landscapes. Our project sought to characterize the forest management activities of land managers and landowners (or "actors" and their influence on wildfire behavior and landscape outcomes by focusing on biophysical and socioeconomic feedbacks in central Oregon (USA. We used an agent-based model (ABM to compile biophysical and social information pertaining to actor behavior, and to project future landscape conditions under alternative management scenarios. Project social scientists were tasked with identifying actors' forest management activities and biophysical and socioeconomic factors that influence them, and with developing decision rules for incorporation into the ABM to represent actor behavior. We (1 briefly summarize what we learned about actor behavior on this fire-prone landscape and how we represented it in an ABM, and (2 more significantly, report our observations about how we organized and functioned as a diverse team of social scientists to fulfill these CHANS research tasks. We highlight several challenges we experienced, involving quantitative versus qualitative data and methods, distilling complex behavior into empirical models, varying sensitivity of biophysical models to social factors, synchronization of research tasks, and the need to

  14. Prediction of Natural Gas Consumption in Different Regions of China Using a Hybrid MVO-NNGBM Model

    Directory of Open Access Journals (Sweden)

    Xiaoyu Wang

    2017-01-01

    Full Text Available The accurate and reasonable prediction of natural gas consumption is significant for the government to formulate energy planning. To this end, we use the multiverse optimizer (MVO algorithm to optimize the parameters of the Nash nonlinear grey Bernoulli model (NNGBM (1,1 and propose a hybrid MVO-NNGBM model to predict the natural gas consumption in 30 regions of China. The results indicate that the prediction precision of the hybrid MVO-NNGBM model is better than that of other grey-based models. According to the forecast results, China’s natural gas consumption will grow rapidly over the next five years and reach 354.1 billion cubic meters (bcm by 2020. Moreover, the spatial distribution of natural gas consumption will shift from being supply oriented towards being demand driven and will be mainly concentrated in coastal and developed provinces.

  15. The Changing Nature of Adult Education in the Age of Transnational Migration: Toward a Model of Recognitive Adult Education

    Science.gov (United States)

    Guo, Shibao

    2015-01-01

    This chapter examines the changing nature of adult education in the age of transnational migration and proposes recognitive adult education as an inclusive model that acknowledges and affirms cultural difference and diversity as positive and desirable assets.

  16. A model for economic evaluation of the use of Adsorbed Natural Gas (ANG); Modelo de avaliacao economica do uso do Gas Natural Adsorvido (GNA)

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Diana C.S.; Cavalcante Junior, Celio L.; Torres, A. Eurico B.; Oliveira Junior, Jose A.; Medeiros, Vanildo M. de [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Campos, Flavio B.; Moura, Newton R. de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES). Gerencia de Gas e Energia; Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Gerencia de Tecnologia de Gas e Energia; Alexandre, Francisco de Assis Souza

    2004-07-01

    Natural gas is currently transported by two main ways: through pipelines and stored in reservoirs, under compressed (CNG) or liquefied (LNG) forms. Adsorbed natural gas (ANG) is a third alternative to vessel storage, which has been intensively reported in the scientific and technical literature. Working pressures are considerably lower for ANG (3,5 MPa as compared to 25 MPa for CNG), which results in lower costs with vessel construction and compression and safer handling. The project ADSPOR, sponsored by PETROBRAS and part of the R and D portfolio of RedeGasEnergia, aims to assess the technical and economical feasibility of storing and transporting natural gas confined in carbon adsorbents. The objectives of this project are the production of high-capacity active carbons, the collection of adsorption data for NG storage and the economic evaluation of ANG. The present work presents a model for cost estimation of the ANG business, which comprises from the compression into ANG vessels until the distribution to the final costumer, taking into account several shipping modes. The variables involved in the model were: compression costs, equipment and materials technical data, costs with product handling and shipping costs for motor ways, railways and inland waterways. These variables were linked so as to generate a cost matrix that may be used to assess investment and calculate the final cost for GNA transport. The model may be used to carry out parameter sensitivity analysis, for decision-making and management purposes. (author)

  17. System Dynamics Model to develop resilience management strategies for lifelines exposed to natural hazards

    Science.gov (United States)

    Pagano, Alessandro; Pluchinotta, Irene; Giordano, Raffaele; Vurro, Michele

    2016-04-01

    . Moving in such direction, System Dynamics Modeling (SDM) is a suitable operative approach. The SDM allows taking into account all resilience dimensions in an integrated and dynamic way. Furthermore, it allows to combine predictive and learning functionality through feedback mechanisms, and to foster active involvement of stakeholders in the modelling process. The present paper show some results of ongoing research activities. The main aim of the work is to describe using SDM, the relationships and interdependencies between drinking water supply infrastructures and societies in building the resilience of urban communities in case of natural disasters. Reflections are carried out on the comparison between two major earthquakes in Italy: L'Aquila in 2009 and Emilia Romagna in 2012. The model aims at defining a quantitative tool to assess the evolution of resilience of drinking water supply system. Specifically, it has been used to evaluate the impact of actions and strategies for resilience improvement on the dynamic evolution of the system, thus suggesting the most suitable ones.

  18. Immunogenic multistage recombinant protein vaccine confers partial protection against experimental toxoplasmosis mimicking natural infection in murine model

    Directory of Open Access Journals (Sweden)

    Yaprak Gedik

    2016-01-01

    To generate a protective vaccine against toxoplasmosis, multistage vaccines and usage of challenging models mimicking natural route of infection are critical cornerstones. In this study, we generated a BAG1 and GRA1 multistage vaccine that induced strong immune response in which the protection was not at anticipated level. In addition, the murine model was orally challenged with tissue cysts to mimic natural route of infection.

  19. Treatment of a multiple sclerosis animal model by a novel nanodrop formulation of a natural antioxidant

    Directory of Open Access Journals (Sweden)

    Binyamin O

    2015-11-01

    Full Text Available Orli Binyamin,1,* Liraz Larush,2,* Kati Frid,1 Guy Keller,1 Yael Friedman-Levi,1 Haim Ovadia,1 Oded Abramsky,1 Shlomo Magdassi,2 Ruth Gabizon1 1Department of Neurology, The Agnes Ginges Center of Human Neurogenetics, Hadassah University Hospital, 2Casali Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel *These authors contributed equally to this work Abstract: Multiple sclerosis (MS is a chronic inflammatory disease of the central nervous system and is associated with demyelination, neurodegeneration, and sensitivity to oxidative stress. In this work, we administered a nanodroplet formulation of pomegranate seed oil (PSO, denominated Nano-PSO, to mice induced for experimental autoimmune encephalomyelitis (EAE, an established model of MS. PSO comprises high levels of punicic acid, a unique polyunsaturated fatty acid considered as one of the strongest natural antioxidants. We show here that while EAE-induced mice treated with natural PSO presented some reduction in disease burden, this beneficial effect increased significantly when EAE mice were treated with Nano-PSO of specific size nanodroplets at much lower concentrations of the oil. Pathological examinations revealed that Nano-PSO administration dramatically reduced demyelination and oxidation of lipids in the brains of the affected animals, which are hallmarks of this severe neurological disease. We propose that novel formulations of natural antioxidants such as Nano-PSO may be considered for the treatment of patients suffering from demyelinating diseases. On the mechanistic side, our results demonstrate that lipid oxidation may be a seminal feature in both demyelination and neurodegeneration. Keywords: nanodrops, PSO, EAE, oxidative stress, neurodegeneration

  20. The Effectiveness of Natural Diarylheptanoids against Trypanosoma cruzi: Cytotoxicity, Ultrastructural Alterations and Molecular Modeling Studies.

    Directory of Open Access Journals (Sweden)

    Vitor Sueth-Santiago

    Full Text Available Curcumin (CUR is the major constituent of the rhizomes of Curcuma longa and has been widely investigated for its chemotherapeutic properties. The well-known activity of CUR against Leishmania sp., Trypanosoma brucei and Plasmodium falciparum led us to investigate its activity against Trypanosoma cruzi. In this work, we tested the cytotoxic effects of CUR and other natural curcuminoids on different forms of T. cruzi, as well as the ultrastructural changes induced in epimastigote form of the parasite. CUR was verified as the curcuminoid with more significant trypanocidal properties (IC50 10.13 μM on epimastigotes. Demethoxycurcumin (DMC was equipotent to CUR (IC50 11.07 μM, but bisdemethoxycurcumin (BDMC was less active (IC50 45.33 μM and cyclocurcumin (CC was inactive. In the experiment with infected murine peritoneal macrophages all diarylheptanoids were more active than the control in the inhibition of the trypomastigotes release. The electron microscopy images showed ultrastructural changes associated with the cytoskeleton of the parasite, indicating tubulin as possible target of CUR in T. cruzi. The results obtained by flow cytometry analysis of DNA content of the parasites treated with natural curcuminoids suggested a mechanism of action on microtubules related to the paclitaxel`s mode of action. To better understand the mechanism of action highlighted by electron microscopy and flow cytometry experiments we performed the molecular docking of natural curcuminoids on tubulin of T. cruzi in a homology model and the results obtained showed that the observed interactions are in accordance with the IC50 values found, since there CUR and DMC perform similar interactions at the binding site on tubulin while BDMC do not realize a hydrogen bond with Lys163 residue due to the absence of methoxyl groups. These results indicate that trypanocidal properties of CUR may be related to the cytoskeletal alterations.

  1. Three-dimensional dose-response models of competing risks and natural life span

    International Nuclear Information System (INIS)

    Raabe, O.G.

    1987-01-01

    Three-dimensional dose-rate/time/response surfaces for chronic exposure to carcinogens, toxicants, and ionizing radiation dramatically clarify the separate and interactive roles of competing risks. The three dimensions are average dose rate, exposure time, and risk. An illustration with computer graphics shows the contributions with the passage of time of the competing risks of death from radiation pneumonitis/fibrosis, lung cancer, and natural aging consequent to the inhalation of plutonium-239 dioxide by beagles. These relationships are further evaluated by mathematical stripping with three-dimensional illustrations that graphically show the resultant separate contribution of each fatal effect. Radiation pneumonitis predominates at high dose rates and lung cancer at intermediate dose rates. Low dose rates result in spontaneous deaths from natural aging, yielding a type of practical threshold for lung cancer induction. Risk assessment is benefited by the insights that become apparent with these three-dimensional models. The improved conceptualization afforded by them contributes to the planning and evaluation of epidemiological analyses and experimental studies involving chronic exposure to toxicants

  2. Directed natural product biosynthesis gene cluster capture and expression in the model bacterium Bacillus subtilis

    Science.gov (United States)

    Li, Yongxin; Li, Zhongrui; Yamanaka, Kazuya; Xu, Ying; Zhang, Weipeng; Vlamakis, Hera; Kolter, Roberto; Moore, Bradley S.; Qian, Pei-Yuan

    2015-03-01

    Bacilli are ubiquitous low G+C environmental Gram-positive bacteria that produce a wide assortment of specialized small molecules. Although their natural product biosynthetic potential is high, robust molecular tools to support the heterologous expression of large biosynthetic gene clusters in Bacillus hosts are rare. Herein we adapt transformation-associated recombination (TAR) in yeast to design a single genomic capture and expression vector for antibiotic production in Bacillus subtilis. After validating this direct cloning ``plug-and-play'' approach with surfactin, we genetically interrogated amicoumacin biosynthetic gene cluster from the marine isolate Bacillus subtilis 1779. Its heterologous expression allowed us to explore an unusual maturation process involving the N-acyl-asparagine pro-drug intermediates preamicoumacins, which are hydrolyzed by the asparagine-specific peptidase into the active component amicoumacin A. This work represents the first direct cloning based heterologous expression of natural products in the model organism B. subtilis and paves the way to the development of future genome mining efforts in this genus.

  3. Differential responses to natural and recombinant allergens in a murine model of fish allergy.

    Science.gov (United States)

    van der Ventel, Michelle L; Nieuwenhuizen, Natalie E; Kirstein, Frank; Hikuam, Christoph; Jeebhay, Mohamed F; Swoboda, Ines; Brombacher, Frank; Lopata, Andreas L

    2011-01-01

    Aerosolized fish proteins are an important cause of allergic airway reactions in both the domestic and the occupational environment. The aim of this study was to investigate inhalant fish-induced allergy in a mouse model and compare immune responses generated by raw and heat-treated fish extracts as well as natural and recombinant forms of the major fish allergen parvalbumin. Mice were sensitized with raw or cooked pilchard extract and challenged intranasally with cooked pilchard extract, purified natural pilchard parvalbumin or recombinant carp parvalbumin (rCyp c1.01). Cooked pilchard extract predominantly sensitized mice to parvalbumin and induced specific IgG1 and IgE antibodies against both pilchard parvalbumin and rCyp c1.01, whereas additional allergens were recognized by mice sensitized with raw extract, including a 36 kDa allergen that was also recognized by fish processing workers and was identified as glyceraldehyde-3-phosphate dehydrogenase. Mice challenged with cooked extract and purified pilchard parvalbumin had increased Th2 cytokine production in mediastinal lymph node cells and splenocytes, whereas mice challenged with rCyp c1.01 did not. This study identifies a new IgE-binding protein that may be important in occupational allergy to fish and demonstrates the feasibility of testing recombinant allergens for immunotherapeutic potential in vivo. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Directed natural product biosynthesis gene cluster capture and expression in the model bacterium Bacillus subtilis

    KAUST Repository

    Li, Yongxin

    2015-03-24

    Bacilli are ubiquitous low G+C environmental Gram-positive bacteria that produce a wide assortment of specialized small molecules. Although their natural product biosynthetic potential is high, robust molecular tools to support the heterologous expression of large biosynthetic gene clusters in Bacillus hosts are rare. Herein we adapt transformation-associated recombination (TAR) in yeast to design a single genomic capture and expression vector for antibiotic production in Bacillus subtilis. After validating this direct cloning plug-and-playa approach with surfactin, we genetically interrogated amicoumacin biosynthetic gene cluster from the marine isolate Bacillus subtilis 1779. Its heterologous expression allowed us to explore an unusual maturation process involving the N-acyl-asparagine pro-drug intermediates preamicoumacins, which are hydrolyzed by the asparagine-specific peptidase into the active component amicoumacin A. This work represents the first direct cloning based heterologous expression of natural products in the model organism B. subtilis and paves the way to the development of future genome mining efforts in this genus.

  5. Evaluation of the Mycobacterium tuberculosis SO2 vaccine using a natural tuberculosis infection model in goats.

    Science.gov (United States)

    Bezos, J; Casal, C; Álvarez, J; Roy, A; Romero, B; Rodríguez-Bertos, A; Bárcena, C; Díez, A; Juste, R; Gortázar, C; Puentes, E; Aguiló, N; Martín, C; de Juan, L; Domínguez, L

    2017-05-01

    The development of new vaccines against animal tuberculosis (TB) is a priority for improving the control and eradication of this disease, particularly in those species not subjected to compulsory eradication programmes. In this study, the protection conferred by the Mycobacterium tuberculosis SO 2 experimental vaccine was evaluated using a natural infection model in goats. Twenty-six goats were distributed in three groups: (1) 10 goats served as a control group; (2) six goats were subcutaneously vaccinated with BCG; and (3) 10 goats were subcutaneously vaccinated with SO 2 . Four months after vaccination, all groups were merged with goats infected with Mycobacterium bovis or Mycobacterium caprae, and tested over a 40 week period using a tuberculin intradermal test and an interferon-γ assay for mycobacterial reactivity. The severity of lesions was determined at post-mortem examination and the bacterial load in tissues were evaluated by culture. The two vaccinated groups had significantly lower lesion and bacterial culture scores than the control group (P<0.05); at the end of the study, the SO 2 vaccinated goats had the lowest lesion and culture scores. These results suggest that the SO 2 vaccine provides some protection against TB infection acquired from natural exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The natural defense system and the normative self model [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Philippe Kourilsky

    2016-05-01

    Full Text Available Infectious agents are not the only agressors, and the immune system is not the sole defender of the organism. In an enlarged perspective, the ‘normative self model’ postulates that a ‘natural defense system’ protects man and other complex organisms against the environmental and internal hazards of life, including infections and cancers. It involves multiple error detection and correction mechanisms that confer robustness to the body at all levels of its organization. According to the model, the self relies on a set of physiological norms, and NONself (meaning : Non Obedient to the Norms of the self is anything ‘off-norms’. The natural defense system comprises a set of ‘civil defenses’ (to which all cells in organs and tissues contribute, and a ‘professional army ‘, made of a smaller set of mobile cells. Mobile and non mobile cells differ in their tuning abilities. Tuning extends the recognition capabilities of NONself by the mobile cells, which increase their defensive function. To prevent them to drift, which would compromise self/NONself discrimination, the more plastic mobile cells need to periodically refer to the more stable non mobile cells to keep within physiological standards.

  7. Modeling Human Natural Killer Cell Development in the Era of Innate Lymphoid Cells.

    Science.gov (United States)

    Scoville, Steven D; Freud, Aharon G; Caligiuri, Michael A

    2017-01-01

    Decades after the discovery of natural killer (NK) cells, their developmental pathways in mice and humans have not yet been completely deciphered. Accumulating evidence indicates that NK cells can develop in multiple tissues throughout the body. Moreover, detailed and comprehensive models of NK cell development were proposed soon after the turn of the century. However, with the recent identification and characterization of other subtypes of innate lymphoid cells (ILCs), which show some overlapping functional and phenotypic features with NK cell developmental intermediates, the distinct stages through which human NK cells develop from early hematopoietic progenitor cells remain unclear. Thus, there is a need to reassess and refine older models of NK cell development in the context of new data and in the era of ILCs. Our group has focused on elucidating the developmental pathway of human NK cells in secondary lymphoid tissues (SLTs), including tonsils and lymph nodes. Here, we provide an update of recent progress that has been made with regard to human NK cell development in SLTs, and we discuss these new findings in the context of contemporary models of ILC development.

  8. Naturalness in low-scale SUSY models and "non-linear" MSSM

    CERN Document Server

    Antoniadis, I; Ghilencea, D M

    2014-01-01

    In MSSM models with various boundary conditions for the soft breaking terms (m_{soft}) and for a higgs mass of 126 GeV, there is a (minimal) electroweak fine-tuning Delta\\approx 800 to 1000 for the constrained MSSM and Delta\\approx 500 for non-universal gaugino masses. These values, often regarded as unacceptably large, may indicate a problem of supersymmetry (SUSY) breaking, rather than of SUSY itself. A minimal modification of these models is to lower the SUSY breaking scale in the hidden sector (\\sqrt f) to few TeV, which we show to restore naturalness to more acceptable levels Delta\\approx 80 for the most conservative case of low tan_beta and ultraviolet boundary conditions as in the constrained MSSM. This is done without introducing additional fields in the visible sector, unlike other models that attempt to reduce Delta. In the present case Delta is reduced due to additional (effective) quartic higgs couplings proportional to the ratio m_{soft}/(\\sqrt f) of the visible to the hidden sector SUSY breaking...

  9. Groundwater flow through a natural fracture. Flow experiments and numerical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Erik [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept of Geology

    1997-09-01

    Groundwater flow and transport play an important role not only for groundwater exploration but also in environmental engineering problems. This report considers how the hydraulic properties of fractures in crystalline rock depend on the fracture aperture geometry. Different numerical models are discussed and a FDM computer code for two- and three- dimensional flow-modelling has been developed. Different relations between the cells in the model are tested and compared with results in the literature. A laboratory experimental work has been done to carry out flow experiments and aperture measurements on the same specimen of a natural fracture. The drilled core sample had fractures parallel to the core axis and was placed inside a biaxial cell during the experiments. The water pressure gradient and the compression stress were varied during the experiments and also a tracer test was done. After the flow experiments, the aperture distribution for a certain compression was measured by injecting an epoxy resin into the fracture. The thickness of the resin layer was then studied in saw cut sections of the sample. The results from the experiments were used to validate numerical and analytical models, based on aperture distribution, for flow and transport simulations. In the disturbed zone around a drift both water and air are present in the fractures. The gas will go to the most wide part of the fracture because the capillarity and the conductivity decrease. The dependence of the effective conductivity on the variance of the conductivity and the effect of extinction of highly conductive cells has also been studied. A discussion of how gas in fractures around a drift can cause a skin effect is modelled and an example is given of what a saturation depending on the magnitude of the flow causes. 25 refs, 17 tabs, 43 figs.

  10. Groundwater flow through a natural fracture. Flow experiments and numerical modelling

    International Nuclear Information System (INIS)

    Larsson, Erik

    1997-09-01

    Groundwater flow and transport play an important role not only for groundwater exploration but also in environmental engineering problems. This report considers how the hydraulic properties of fractures in crystalline rock depend on the fracture aperture geometry. Different numerical models are discussed and a FDM computer code for two- and three- dimensional flow-modelling has been developed. Different relations between the cells in the model are tested and compared with results in the literature. A laboratory experimental work has been done to carry out flow experiments and aperture measurements on the same specimen of a natural fracture. The drilled core sample had fractures parallel to the core axis and was placed inside a biaxial cell during the experiments. The water pressure gradient and the compression stress were varied during the experiments and also a tracer test was done. After the flow experiments, the aperture distribution for a certain compression was measured by injecting an epoxy resin into the fracture. The thickness of the resin layer was then studied in saw cut sections of the sample. The results from the experiments were used to validate numerical and analytical models, based on aperture distribution, for flow and transport simulations. In the disturbed zone around a drift both water and air are present in the fractures. The gas will go to the most wide part of the fracture because the capillarity and the conductivity decrease. The dependence of the effective conductivity on the variance of the conductivity and the effect of extinction of highly conductive cells has also been studied. A discussion of how gas in fractures around a drift can cause a skin effect is modelled and an example is given of what a saturation depending on the magnitude of the flow causes

  11. Use of natural analogues to support radionuclide transport models for deep geological repositories for long lived radioactive wastes

    International Nuclear Information System (INIS)

    1999-10-01

    Plans to dispose high level and long lived radioactive wastes in deep geological repositories have raised a number of unique problems, mainly due to the very long time-scales which have to be considered. An important way to help to evaluate performance and provide confidence in the assessment of safety in the long term is to carry out natural analogue studies. Natural analogues can be regarded as long term natural experiments the results or outcome of which can be observed, but which, by definition, are uncontrolled by humans. Studies of natural analogues have been carried out for more than two decades, although the application of information from them is only relatively recently becoming scientifically well ordered. This report is part of a the IAEA's programme on radioactive waste management dealing with disposal system technology for high level and long lived radioactive waste. It presents the current status of natural analogue information in evaluating models for radionuclide transport by groundwater. In particular, emphasis is given to the most useful aspects of quantitative applications for model development and testing (geochemistry and coupled transport models). The report provides an overview of various natural analogues as reference for those planning to develop a research programme in this field. Recommendations are given on the use of natural analogues to engender confidence in the safety of disposal systems. This report is a follow up of Technical Reports Series No. 304 on Natural Analogues in Performance Assessments for the Disposal of Long Lived Radioactive Waste (1989)

  12. Structural characterization of rubber from jackfruit and euphorbia as a model of natural rubber.

    Science.gov (United States)

    Mekkriengkrai, Dararat; Ute, Koiichi; Swiezewska, Ewa; Chojnacki, Tadeusz; Tanaka, Yasuyuki; Sakdapipanich, Jitladda T

    2004-01-01

    A structural study of low molecular weight rubbers from Jackfruit (Artocarpus heterophyllus) and Painted spurge (Euphorbia heterophylla) was carried out as model compounds of natural rubber from Hevea brasiliensis. The rubber content of latex from Jackfruit was 0.4-0.7%, which is very low compared with that of 30-35% in the latex from Hevea tree. The rubber from Jackfruit latex was low molecular weight with narrow unimodal molecular weight distribution (MWD), whereas that obtained from E. heterophylla showed very broad MWD. The 1H and 13C NMR analyses showed that Jackfruit rubber consists of a dimethylallyl group and two trans-isoprene units connected to a long sequence of cis-isoprene units. The alpha-terminal group of Jackfruit rubber was presumed to be composed of a phosphate group based on the presence of 1H NMR signal at 4.08 ppm corresponding to the terminal =CH-CH2OP group.

  13. Modeling Air Permeability in Variably Saturated Soil from Two Natural Clay Gradients

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda T K K; Arthur, Emmanuel; Møldrup, Per

    2013-01-01

    measurements from two Danish arable fields, each located on natural clay gradients, this study presents a pore tortuosity–disconnectivity analysis to characterize the soil–gas phase. The main objective of this study is to investigate the effect of soil–moisture condition, clay content, and other potential......Understanding soil–gas phase properties and processes is important for finding solutions to critical environmental problems such as greenhouse gas emissions and transport of gaseous-phase contaminants in soils. Soil–air permeability, ka (μm2), is the key parameter governing advective gas movement...... in soil and is controlled by soil physical characteristics representing soil texture and structure. Models predicting ka as a function of air-filled porosity (ɛ) often use a reference-point measurement, for example, ka,1000 at ɛ1000 (where the measurement is done at a suction of –1000 cm H2O). Using ka...

  14. Development of a natural gas systems analysis model (GSAM). Annual report, July 1996--July 1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The objective of GSAM development is to create a comprehensive, non-proprietary, microcomputer model of the North American natural gas system. GSAM explicitly evaluates the key components of the system, including the resource base, exploration and development practices, extraction technology performance and costs, project economics, transportation costs and restrictions, storage, and end-use. The primary focus is the detailed characterization of the resource base at the reservoir and subreservoir level. This disaggregation allows direct evaluation of alternative extraction technologies based on discretely estimated, individual well productivity, required investments, and associated operating costs. GSAM`s design allows users to evaluate complex interactions of current and alternative future technology and policy initiatives as they directly impact the gas market. GSAM development has been ongoing for the past five years. Key activities completed during the past year are described.

  15. Development of a natural gas systems analysis model (GSAM). Annual report, July 1996--July 1997

    International Nuclear Information System (INIS)

    1997-01-01

    The objective of GSAM development is to create a comprehensive, non-proprietary, microcomputer model of the North American natural gas system. GSAM explicitly evaluates the key components of the system, including the resource base, exploration and development practices, extraction technology performance and costs, project economics, transportation costs and restrictions, storage, and end-use. The primary focus is the detailed characterization of the resource base at the reservoir and subreservoir level. This disaggregation allows direct evaluation of alternative extraction technologies based on discretely estimated, individual well productivity, required investments, and associated operating costs. GSAM's design allows users to evaluate complex interactions of current and alternative future technology and policy initiatives as they directly impact the gas market. GSAM development has been ongoing for the past five years. Key activities completed during the past year are described

  16. Using physical and numerical models to study possibilities of storing natural gas in horizontal layers

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, M; Marrast, j

    1969-11-01

    The absence of suitable structures in some regions has led Gaz de France to investigate the storage of natural gas in horizontal layers. Research aimed at completing work done in this field by Soviet researchers has been carried out at the Institut Francais du Petrole using physical and numerical models together with computing. This research included an examination of storage stability, of how the effective volume of gas evolved during different cycles, of how the gas bubble migrates under the effect of a slight dip, and of the influence of instabilities. The possibility of storing gas in horizontal or sub-horizontal layers was thus justified from a theoretical viewpoint. When the time comes to make a decision concerning the creation of such a storage area, it is the economic factor that will be preponderant. The effective volume of recoverable gas has turned out to depend to a large extent on the thickness of the layer. (12 refs.)

  17. Modelling natural convection in a heated vertical channel for room ventilation

    International Nuclear Information System (INIS)

    Rodrigues, A.M.; Canha da Piedade, A.; Lahellec, A.; Grandpeix, J.Y.

    2000-01-01

    Solar-air collectors installed on the south-facing walls of school buildings have been tried out in Portugal as a passive means of improving indoor air quality without prejudice to thermal comfort requirements. A numerical investigation of the behaviour of these systems, typified as vertical channels opened at both ends, is presented for typical geometries and outdoor conditions. The study is carried out with natural convection and assumes that the induced flow is turbulent and two-dimensional. The fully averaged equations of motion and energy, added to a two-equation turbulence model, are discretized and solved following the concepts of TEF (Transfer Evolution Formalism) using a finite volume method. Flow and temperature fields are produced and results presented in terms of temperature and velocity distributions at the exit section of the duct. These enable a better understanding of the developing flow and can be helpful in the design phase of this type of system. (author)

  18. A stochastic model for the synthesis and degradation of natural organic matter. Part III: Modeling Cu(II) complexation

    Energy Technology Data Exchange (ETDEWEB)

    Cabaniss, Stephen E. [Department of Chemistry, University of New Mexico, Albuquerque, NM 87131 (United States)], E-mail: cabaniss@unm.edu; Maurice, Patricia A. [Department of Geology and Civil Engineering, University of Notre Dame (United States); Madey, Greg [Department of Computer Science, University of Notre Dame (United States)

    2007-08-15

    An agent-based biogeochemical model has been developed which begins with biochemical precursor molecules and simulates the transformation and degradation of natural organic matter (NOM). This manuscript presents an empirical quantitative structure activity relationship (QSAR) which uses the numbers of ligand groups, charge density and heteroatom density of a molecule to estimate Cu-binding affinity (K{sub Cu}{sup '}) at pH 7.0 and ionic strength 0.10 for the molecules in this model. Calibration of this QSAR on a set of 41 model compounds gives a root mean square error of 0.88 log units and r{sup 2} 0.93. Two simulated NOM assemblages, one beginning with small molecules (tannins, terpenoids, flavonoids) and one with biopolymers (protein, lignin), give markedly different distributions of logK{sub Cu}{sup '}. However, calculations based on these logK{sub Cu}{sup '} distributions agree qualitatively with published experimental Cu(II) titration data from river and lake NOM samples.

  19. Modelling natural electromagnetic interference in man-made conductors for space weather applications

    Science.gov (United States)

    Trichtchenko, Larisa

    2016-04-01

    Power transmission lines above the ground, cables and pipelines in the ground and under the sea, and in general all man-made long grounded conductors are exposed to the variations of the natural electromagnetic field. The resulting currents in the networks (commonly named geomagnetically induced currents, GIC), are produced by the conductive and/or inductive coupling and can compromise or even disrupt system operations and, in extreme cases, cause power blackouts, railway signalling mis-operation, or interfere with pipeline corrosion protection systems. To properly model the GIC in order to mitigate their impacts it is necessary to know the frequency dependence of the response of these systems to the geomagnetic variations which naturally span a wide frequency range. For that, the general equations of the electromagnetic induction in a multi-layered infinitely long cylinder (representing cable, power line wire, rail or pipeline) embedded in uniform media have been solved utilising methods widely used in geophysics. The derived electromagnetic fields and currents include the effects of the electromagnetic properties of each layer and of the different types of the surrounding media. This exact solution then has been used to examine the electromagnetic response of particular samples of long conducting structures to the external electromagnetic wave for a wide range of frequencies. Because the exact solution has a rather complicated structure, simple approximate analytical formulas have been proposed, analysed and compared with the results from the exact model. These approximate formulas show good coincidence in the frequency range spanning from geomagnetic storms (less than mHz) to pulsations (mHz to Hz) to atmospherics (kHz) and above, and can be recommended for use in space weather applications.

  20. Urinary bladder cancer in dogs, a naturally occurring model for cancer biology and drug development.

    Science.gov (United States)

    Knapp, Deborah W; Ramos-Vara, José A; Moore, George E; Dhawan, Deepika; Bonney, Patty L; Young, Kirsten E

    2014-01-01

    Each year more than 65,000 people are diagnosed with urinary bladder cancer, and more than 14,000 people die from the disease in the United States. Studies in relevant animal models are essential to improve the management of bladder cancer. Naturally occurring bladder cancer in dogs very closely mimics human invasive bladder cancer, specifically high-grade invasive transitional cell carcinoma (TCC; also referred to as invasive urothelial carcinoma) in cellular and molecular features; biological behavior, including sites and frequency of metastasis; and response to therapy. Canine bladder cancer complements experimentally induced rodent tumors in regard to animal models of bladder cancer. Results of cellular and molecular studies and -omics analyses in dogs are expected to lead to improved detection of TCC and preneoplastic lesions, earlier intervention, better prediction of patient outcome, and more effective TCC management overall. Studies in dogs are being used to help define heritable risks (through very strong breed-associated risk) and environment risks and to evaluate prevention and treatment approaches that benefit humans as well as dogs. Clinical treatment trials in pet dogs with TCC are considered a win-win scenario by clinician scientists and pet owners. The individual dog benefits from effective treatment, the results are expected to help other dogs, and the findings are expected to ultimately help humans with TCC. This article provides an overview of canine TCC, a summary of the similarities and differences between canine and human invasive TCC, and examples of the types of valuable translational research that can be done using dogs with naturally occurring TCC. © The Author 2014. Published by Oxford University Press on behalf of the Institute for Laboratory Animal Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.