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Sample records for 233u self-fueling regime

  1. Preserving high-purity 233U

    The MARC X Conference hosted a workshop for the scientific community to communicate needs for high-purity 233U and its by-products in order to preserve critical items otherwise slated for downblending and disposal. Currently, only small portions of the U.S. holdings of separated 233U are being preserved. However, many additional kilograms of 233U (>97 % pure) still are destined to be disposed, and it is unlikely that this material will ever be replaced due to a lack of operating production capability. Summaries of information conveyed at the workshop and feedback obtained from the scientific community are presented herein. (author)

  2. Benchmark testing of 233U evaluations

    In this paper we investigate the adequacy of available 233U cross-section data (ENDF/B-VI and JENDL-3) for calculation of critical experiments. An ad hoc revised 233U evaluation is also tested and appears to give results which are improved relative to those obtained with either ENDF/B-VI or JENDL-3 cross sections. Calculations of keff were performed for ten fast benchmarks and six thermal benchmarks using the three cross-section sets. Central reaction-rate-ratio calculations were also performed

  3. Repository criticality control for 233U using depleted uranium

    The US is evaluating methods for the disposition of excess weapons-usable 233U, including disposal in a repository. Isotopic dilution studies were undertaken to determine how much depleted uranium (DU) would need to be added to the 233U to minimize the potential for nuclear criticality in a repository. Numerical evaluations were conducted to determine the nuclear equivalence of different 235U enrichments to 233U isotopically diluted with DU containing 0.2 wt% 235U. A homogeneous system of silicon dioxide, water, 233U, and DU, in which the ratio of each component was varied, was used to determine the conditions of maximum nuclear reactivity. In terms of preventing nuclear criticality in a repository, there are three important limits from these calculations. 1. Criticality safe in any nonnuclear system: The required isotopic dilution to ensure criticality under all conditions, except in the presence of man-made nuclear materials (beryllium, etc.), is ≅1.0% 235U in 238U. The equivalent 233U enrichment level is 0.53 wt% 233U in DU. 2. Critically safe in natural systems: The lowest 235U enrichment found in a natural reactor at shutdown was approximately1.3%. French studies, based on the characteristics of natural uranium ore bodies, indicate that a minimum enrichment of approximately1.28% 235U is required for criticality. These data suggest that nuclear criticality from migrating uranium is not realistic unless the 235U enrichments exceed approximately1.3%, which is a result that is equivalent to 0.72% 233U in DU. 3. Criticality safety equivalent to light water reactor (LWR) spent nuclear fuel (SNF): The 233U can be diluted with DU so that the uranium criticality characteristics match SNF uranium. Whatever repository criticality controls are used for SNF can then be used for 233U. The average LWR SNF assay (after decay of plutonium isotopes to uranium isotopes) is 1.5% 235U equivalent in 238U. This is equivalent to diluting 233U to 0.81% in DU

  4. Testing of 233U evaluations with criticality benchmarks

    To validate and improve the quality of the complete set of evaluated nuclear reaction data for 233U, criticality benchmarks with fast, epithermal and thermal spectra from ICSBEP handbook were selected to test 233U evaluations from CENDL-3.1, ENDF/B-Ⅶ.0, JENDL-3.3 and JENDL-4.0. The effective multiplication factors keff of selected benchmarks were calculated with the Monte Carlo code MCNP5 and compared with the benchmark values. The results were analyzed with trend against energy spectrum index and sensitivity analysis. In present validation, the underestimation of keff for benchmarks with thermal, epithermal or some of fast spectra is the main problem existed in the tested evaluations. From the view of thermal reactors design, the 233U evaluation from ENDF/B-Ⅶ.0 shows better performance than other file tested, but still overestimates the contribution of capture reaction in resonance region. (authors)

  5. Experimental 233U nondestructive assay with a random driver

    Nondestructive assay (NDA) of 233U in quantities up to 15 grams containing 7 ppM 232U age 2 years was investigated with a random driver. A passive singles counting technique showed a reproducibility within 0.2% at the 95% confidence level. This technique would be applicable throughout a process in which all of the 233U had the same 232U content at the same age. Where the 232U content varies, determination of 233U fissile content would require active NDA. Active coincidence counting utilizing a 238Pu, Li neutron source and a plastic scintillator detector system showed a reproducibility limit within 15% at the 95% confidence limit. The active technique was found to be very dependent on the detector system resolving time in order to make proper random coincidence corrections associated with the high gamma activity from the 232U decay chain

  6. Updated and revised neutron reaction data for 233U

    YU Bao-Sheng; CHEN Guo-Chang; ZHANG Hua; CAO Wen-Tian; TANG Guo-You; TAO Xi

    2013-01-01

    A complete set of n+233U neutron reaction data from 10-5 eV-20 MeV is updated and revised based on the evaluated experimental data and the feedback information of various benchmark tests.The main revised quantities are nubars,cross sections as well as angular distributions,etc.The benchmark tests indicate that the present evaluated data achieve very promising results.

  7. Thermal Stabilization of 233UO2, 233UO3, and 233U3O8

    This report identifies an appropriate thermal stabilization temperature for 233U oxides. The temperature is chosen principally on the basis of eliminating moisture and other residual volatiles. This report supports the U. S. Department of Energy (DOE) Standard for safe storage of 233U (DOE 2000), written as part of the response to Recommendation 97-1 of the Defense Nuclear Facilities Safety Board (DNFSB), addressing safe storage of 233U

  8. Isotopic dilution of 233U with depleted uranium for criticality safety in processing and disposal

    The disposal of excess 233U as waste is being considered. Because 233U is a fissile material, a key requirement for processing 233U to a final waste form and disposing of it is the avoidance of nuclear criticality. For many processing and disposal options, isotopic dilution is the most feasible and preferred option to avoid nuclear criticality. Isotopic dilution is dilution of fissile 233U with nonfissile 238U. The use of isotopic dilution removes any need to control nuclear criticality in process or disposal facilities through geometry or chemical composition. Isotopic dilution allows the use of existing waste management facilities that are not designed for significant quantities of fissile materials to be used for processing and disposing of 233U. The amount of isotopic dilution required to reduce criticality concerns to reasonable levels was determined in this study to be approximately 0.53 wt % 233U. The numerical calculations used to define this limit consisted of a homogeneous system of silicon dioxide (SiO2), water (H2O), 233U and depleted uranium (DU) in which the ratio of each component was varied to learn the conditions of maximum nuclear reactivity. About 188 parts of DU (0.2 wt % 235U) are required to dilute 1 part of 233U to this limit in a water-moderated system with no SiO2 present. Thus for the U.S. inventory of 233U, several hundred metric tons of DU would be required for isotopic dilution

  9. Separation and estimation of 229Th and 233U by alpha and gamma ray spectrometric technique

    The individual estimation of 233U and 229Th in a plancheted source made out of liquid sample were done by using an alpha and γ-ray spectrometric techniques. Estimation of 229Th in the plancheted source was done by γ-ray spectrometry and 233U by alpha spectrometry after subtracting the estimated amount of 229Th. In spite of the same alpha energy of 4.8 MeV, the individual estimation of 233U and 229Th based on present technique is superior to conventional techniques and important in the 232Th-233U fuel reprocessing cycle of AHWR and ADSs. The activity of 229Th was also radiochemically separated from its parent activity of 233U by using an ion exchange resin and the purity was checked by the above mentioned technique. (author)

  10. Performance analysis of 233U for fixed bed nuclear reactors

    Criticality and burn up behavior of the Fixed Bed Nuclear Reactor (FBNR) are investigated for the mixed fuel 233UO2/ThO2 as an alternative to low enriched 235UO2 fuel. CERMET fuel with a zirconium matrix and cladding has been used throughout the study. The main results of the study can be summarized as follows: Reactor criticality is already achieved by ∝2% 233UO2 with the mixed 233UO2/ThO2 fuel. At higher 233U fractions, reactor criticality rises rapidly and exceeds keff > 1.5 already by 9% 233UO2. With 100% 233UO2, start up criticality can reach keff = 2.0975. Time dependent reactor criticality keff and fuel burn up have been investigated for two different mixed fuel 233UO2/ThO2 compositions, namely: 4% 233UO2 + 96% ThO2 for a reactor power of 40 MWel (120 MWth) and 9% 233UO2 + 91% ThO2 for a reactor power of 70 MWel (210 MWth). Sufficient reactor criticality (keff > 1.06) for continuous operation without fuel change can be sustained during ∝ 5 and 12 years with 4% and 9% 233UO2 fractions in the mixed fuel, leading to burn ups of ∝ 36000 and > 105000 MWD/t, respectively. Thorium based fuel produces no prolific uranium. Plutonium production remains negligible. (orig.)

  11. Improved AHWR equilibrium core cluster for self sustenance in 233U

    Advance Heavy Water Reactor (AHWR) is being designed with many advance features like negative coolant void reactivity, heat removal through natural circulation and other passive safety features. The AHWR is a 920 MWth, vertical pressure tube type thorium-based reactor cooled by boiling light water and moderated by heavy water and designed to maximise power production from thorium. The equilibrium fuel cycle is based on the conversion of naturally available thorium into fissile 233U, driven by plutonium as external fissile feed. The basic fuel cycle is based on the fact that the AHWR core should be self-sustaining in 233U. The self sustenance in 233U can be achieved by using two types of equilibrium core clusters. In this paper we have done a study where self sustenance in 233U can be achieved by using only single type of cluster. (author)

  12. Comparative studies on plutonium and 233U utilization in miniFUJI MSR

    Molten salt reactor (MSR) has many merits such as safety enhancement and capability to be used for hydrogen production. A comparative evaluation of plutonium and 233U utilization in miniFUJI MSR has been performed. Reactor grade plutonium (RGPu), weapon grade plutonium (WGPu), and super grade plutonium (SGPu) have been utilized in the present study. The reactors can obtain their criticality condition with the 233U concentration in the Th-233U fuel, RGPu concentration in Th-RGPu fuel, WGPu concentration in Th-WGPu fuel, and SGPu concentration in Th-SGPu fuel of 0.52%, 5.76%, 2.16%, and 1.96%, respectively. The Th-233U fuel results in the soft neutron spectra of miniFUJI reactor. The neutron spectra turn into harder with the enlarging of plutonium concentration in loaded fuel where Th-RGPu fuel gives the hardest neutron spectra. (author)

  13. Initial ORNL site assessment report on the storage of 233U

    The 233U storage facility at ORNL is Building 3019. The inventory stored in Building 3019 consists of 426.5 kg of 233U contained in 1,387.1 kg of total uranium. The inventory is primarily in the form of uranium oxides; however, uranium metal and other compounds are also stored. Over 99% of the inventory is contained in 1,007 packages stored in tube vaults within the facility. A tank of thorium nitrate solution, the P-24 Tank, contains 0.13 kg of 233U in ∼ 4,000 gal. of solution. The facility is receiving additional 233U for storage from the remediation of the Molten Salt Reactor Experiment (MSRE) at ORNL. Consolidation of material from sites with small holdings is also adding to the 233U inventory. Additionally, small quantities (233U are in other research facilities at ORNL. A risk assessment process was chosen to evaluate the stored material and packages based on available package records. The risk scenario was considered the failure of a package (or a group of similar packages) in the Building 3019 inventory. The probability of such a failure depends on packaging factors such as the age and material of construction of the containers. The consequence of such a failure depends on the amount and form of the material within the packages. One thousand seven packages were categorized with this methodology resulting in 859 low-risk packages, 147 medium-risk packages, and 1 high-risk package. This initial assessment also documents the status of the evaluation of the Building 3019 and its systems for safe storage of 233U. The final assessment report for ORNL storage of 233U is scheduled for June 1999. The report will document the facility assessments, the specific package inspection plan, and the results of initial package inspections

  14. Interim assessment of the denatured 233U fuel cycle: feasibility and nonproliferation characteristics

    A fuel cycle that employs 233U denatured with 238U and mixed with thorium fertile material is examined with respect to its proliferation-resistance characteristics and its technical and economic feasibility. The rationale for considering the denatured 233U fuel cycle is presented, and the impact of the denatured fuel on the performance of Light-Water Reactors, Spectral-Shift-Controlled Reactors, Gas-Cooled Reactors, Heavy-Water Reactors, and Fast Breeder Reactors is discussed. The scope of the R, D and D programs to commercialize these reactors and their associated fuel cycles is also summarized and the resource requirements and economics of denatured 233U cycles are compared to those of the conventional Pu/U cycle. In addition, several nuclear power systems that employ denatured 233U fuel and are based on the energy center concept are evaluated. Under this concept, dispersed power reactors fueled with denatured or low-enriched uranium fuel are supported by secure energy centers in which sensitive activities of the nuclear cycle are performed. These activities include 233U production by Pu-fueled transmuters (thermal or fast reactors) and reprocessing. A summary chapter presents the most significant conclusions from the study and recommends areas for future work

  15. Interim assessment of the denatured /sup 233/U fuel cycle: feasibility and nonproliferation characteristics

    Abbott, L.S.; Bartine, D.E.; Burns, T.J. (eds.)

    1978-12-01

    A fuel cycle that employs /sup 233/U denatured with /sup 238/U and mixed with thorium fertile material is examined with respect to its proliferation-resistance characteristics and its technical and economic feasibility. The rationale for considering the denatured /sup 233/U fuel cycle is presented, and the impact of the denatured fuel on the performance of Light-Water Reactors, Spectral-Shift-Controlled Reactors, Gas-Cooled Reactors, Heavy-Water Reactors, and Fast Breeder Reactors is discussed. The scope of the R, D and D programs to commercialize these reactors and their associated fuel cycles is also summarized and the resource requirements and economics of denatured /sup 233/U cycles are compared to those of the conventional Pu/U cycle. In addition, several nuclear power systems that employ denatured /sup 233/U fuel and are based on the energy center concept are evaluated. Under this concept, dispersed power reactors fueled with denatured or low-enriched uranium fuel are supported by secure energy centers in which sensitive activities of the nuclear cycle are performed. These activities include /sup 233/U production by Pu-fueled transmuters (thermal or fast reactors) and reprocessing. A summary chapter presents the most significant conclusions from the study and recommends areas for future work.

  16. Final Oak Ridge National Laboratory Site Assessment Report on the Storage of 233U

    This assessment characterizes the 233U inventories and storage facility at Oak Ridge National Laboratory (ORNL). This assessment is a commitment in the U.S. Department of Energy (DOE) Implementation Plan (IP), ''Safe Storage of Uranium-233,'' in response to the Defense Nuclear Facilities Safety Board's Recommendation 97-1

  17. Recovery of 233U from waste and minimization of modifier with supercritical fluid extraction

    The supercritical fluid extraction (SFE) method was used to remove 233U from a real time tissue paper waste generated in our laboratory and resulted in about 97% of extraction efficiency. Optimization of modifier flow rate was carried out to minimize the generation of secondary liquid waste, a significant endeavour in the context of large-scale waste treatment plant. (author)

  18. Comparison on decay process of explosive products for 233U and weapon-grade plutonium

    Comparison on the nuclear explosive products' radioactivity, biological hazard potential , energy deposition after nuclear explosion between the model of 233U and the model of weapon- grade plutonium was made. The detail analysis of the process of above physics quantities in the model of weapon-grade Plutonium was also given

  19. Radiological safety experience in the fabrication of alloy plate fuels bearing 233U/Pu

    The first incidence of 233U-bearing fuel fabrication in India was the production of aluminum-clad Al-233U alloy fuel for the Kamini research reactor. The reactor physics experiments for this fuel are now being carried out in the Purnima III critical assembly, where Al-Pu alloy plate fuels will also be used. Both types of fuels were fabricated in the radiometallurgy laboratories of Bhabha Atomic Research Centre. The hazard potential of each step, evaluated from the site-specific radiological field data, is summarized. The parameters analyzed for this purpose include external and internal radiation hazards, contamination hazards, age of fuel material (i.e., time after separation), and experimental thermoluminescent detector exposure data. Gamma spectrometric data of the finished fuel plates were also analyzed for their utility in checking the material inventory. The collective dose equivalent from the fabrication operations for 12 subassemblies (9 bearing 233U and 3 bearing plutonium) was 67 mSv, arising from external exposures only. The internal exposure was nil. Fabrication of fuel plates constituted >60% of the total exposure. Fabrication of fuel subassemblies and quality control inspection at all the stages accounted for the remaining radiation exposure. Handling of 233U/Pu-bearing fuels is likely to increase in the years ahead in India. In this context, analysis of radiological field data has yielded useful guidelines for future work

  20. Breeding of 233U in the thorium-uranium fuel cycle in VVER reactors using heavy water

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the 233U-232Th oxide fuel of water-moderated reactors with variable water composition (D2O, H2O) that ensures breeding of the 233U and 235U isotopes. The method is comparatively simple to implement.

  1. Emerging new options for harnessing the Th-233U cycle in India

    The recent development of the concept of Fusion Breeders especially the invention of the Fission Suppressed Blanket, coupled with parallel rapid strides in fusion technology (particularly of Tokamaks) has given a welcome new boost to the prospects of harnessing the Th-233U cycle. Their studies show that even sub-Lawson Fusion Breeders which are net consumers of electrical energy will be good enough to give adequate growth rates of nuclear generating capacity, provided the fusion bred 233U is used in either fast or thermal breeders of thermal near-breeders having high conversion ratios (>0.98). The paper presents an overview of the main results of studies underway in these areas both at the Bhabha Atomic Research Centre (BARC), Trombay and the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam

  2. Analysis of the BNL ThO2-233U exponential experiments

    The BNL ThO2--3 w/o 233U light-water-moderated exponential experiments were analyzed to evaluate (1) cross section library sets for 233U and 232Th, and (2) correlations with measured ThO2 resonance integral data. A total of six cross section library sets were evaluated, including ENDF/B-2 and ENDF/B-3 libraries for 232Th, ENDF/B-2 library for 233U, and ThO2 resonance integral correlations based on data by Weitman and Pettus, Hardy and Palowitch, and corrections to the latter data by Steen. A modified version of the LEOPARD code was used throughout this analysis. The principle results of this work are as follows: (1) The library set containing ENDF/B-2 data for 233U and ENDF/B-3 data for 232Th, together with ThO2 resonance integral correlation based on Steen's corrections to the Hardy and Palowitch data, yields the best agreement with measurements, giving an average k/sub eff/ of 0.9975 with a standard deviation of 0.0067 for the 21 analyzed configurations. (2) With respect to this ''best'' set, the ENDF/B-2 232Th data is less reactive than the corresponding ENDF/B-3 data by approximately 0.1 percent Δk. (3) The ThO2 resonance integral correlation based on data by Weitman and Pettus yields resonance integrals that are consistently higher than those produced by the correlation with Steen's values, even though the latter is normalized to an infinitely dilute resonance integral of 85.9 barns (0.5 ev cutoff), while the former is normalized to a corresponding value of 80 barns. Thus, with respect to the ''best'' set, the ThO2 resonance integral correlation based on the Weitman and Pettus data is less reactive by approximately 0.7 percent Δk

  3. Measurement and analysis of anti ν energy dependence for 233U, 238U, 239Pu

    The energy dependence of the average yield of prompt neutrons per fission (anti ν) for U233, U238 and Pu239 in the incident neutron energy range (Esub(n)) up to 5 MeV has been studied using an electrostatic accelerator. The recommended curves for anti ν (Esub(n)) has been obtained with the help of the polynomial least square method fitting. The resons of deviations from the linear dependence have been analysed

  4. Compilation of criticality data involving thorium or 233U and light water moderation

    Gore, B.F.

    1978-07-01

    The literature has been searched for criticality data for light water moderated systems which contain thorium or /sup 233/U, and data found are compiled herein. They are from critical experiments, extrapolations, and exponential experiments performed with homogeneous solutions and metal spheres of /sup 233/U; with lattices of fuel rods containing highly enriched /sup 235/UO/sub 2/ - ThO/sub 2/ and /sup 233/UO/sub 2/ - ThO/sub 2/; and with arrays of cyclinders of /sup 233/U solutions. The extent of existing criticality data has been compared with that necessary to implement a thorium-based fuel cycle. No experiments have been performed with any solutions containing thorium. Neither do data exist for homogeneous /sup 233/U systems with H/U < 34, except for solid metal systems. Arrays of solution cylinders up to 3 x 3 x 3 have been studied. Data for solutions containing fixed or soluble poisons are very limited. All critical lattices using /sup 233/UO/sub 2/ - ThO/sub 2/ fuels (LWBR program) were zoned radially, and in most cases axially also. Only lattice experiments using /sup 235/UO/sub 2/ - ThO/sub 2/ fuels have been performed using a single fuel rod type. Critical lattices of /sup 235/UO/sub 2/ - ThO/sub 2/ rods poisoned with boron have been measured, but only exponential experiments have been performed using boron-poisoned lattices of /sup 233/UO/sub 2/ - ThO/sub 2/ rods. No criticality data exist for denatured fuels (containing significant amounts of /sup 238/U) in either solution or lattice configurations.

  5. Final purification of 233U from thorium by Dowex 50x4 in Thorex process

    The 233U product obtained after a single cycle 5% tributyl phosphate/shell sol T extraction, scrubbing and stripping often contains significant amount of thorium as impurity. Further purification is normally carried out using ion exchange. The present paper summarises the results of the studies carried out to find out the various factors responsible for the extraordinary binding of thorium ion at the exchanger site while exploring the possibility of eluting total thorium using HNO3 alone

  6. Core design options for high conversion BWRs operating in Th–233U fuel cycle

    Highlights: • BWR core operating in a closed self-sustainable Th–233U fuel cycle. • Seed blanket optimization that includes assembly size array and axial dimensions. • Fully coupled MC with fuel depletion and thermo-hydraulic feedback modules. • Thermal-hydraulic analysis includes MCPR observation. -- Abstract: Several options of fuel assembly design are investigated for a BWR core operating in a closed self-sustainable Th–233U fuel cycle. The designs rely on an axially heterogeneous fuel assembly structure consisting of a single axial fissile zone “sandwiched” between two fertile blanket zones, in order to improve fertile to fissile conversion ratio. The main objective of the study was to identify the most promising assembly design parameters, dimensions of fissile and fertile zones, for achieving net breeding of 233U. The design challenge, in this respect, is that the fuel breeding potential is at odds with axial power peaking and the core minimum critical power ratio (CPR), hence limiting the maximum achievable core power rating. Calculations were performed with the BGCore system, which consists of the MCNP code coupled with fuel depletion and thermo-hydraulic feedback modules. A single 3-dimensional fuel assembly having reflective radial boundaries was modeled applying simplified restrictions on the maximum centerline fuel temperature and the CPR. It was found that axially heterogeneous fuel assembly design with a single fissile zone can potentially achieve net breeding, while matching conventional BWR core power rating under certain restrictions to the core loading pattern design

  7. Investigations on production of 233U using few pin thoria in existing PHWRs

    Thorium is not a fissile material and cannot be used to either start or sustain the chain reaction. Therefore, a reactor using thorium would also need either enriched uranium or plutonium to sustain the chain reaction until enough of the thorium has converted to fissile 233U. In order to retrieve and reprocess the irradiated fuel, the bundle is designed with few thoria pins and rest SEU pins. In the present study, different pin configurations of thoria in 19 and 37 element fuel clusters of Indian PHWRs have been considered. The lattice calculations have been done using the multi-group transport theory code CLUB. The variations of k∞ versus burn up are depicted in the paper. The production of 233U (considering also the decay of 233Pa into 233U) is also shown. Average discharge burn ups of the order 20 and 17 GWd/Te can be achieved with the use of thoria pins in 19 and 37 element fuel clusters respectively with appropriate bundle shift scheme. Derating of power is required during operation because of bundle power restrictions. It is found that 1 pin thoria configuration is preferable from the point of view of fuel requirements and power reduction consideration. Since 37 element fuel cluster used in 540 MWe PHWR fuel has large margins in bundle power, the restriction in power operation is much less than 19 element fuel cluster used in 220 MWe PHWR

  8. Criticality safety validation: Simple geometry, single unit {sup 233}U systems

    Putman, V.L.

    1997-06-01

    Typically used LMITCO criticality safety computational methods are evaluated for suitability when applied to INEEL {sup 233}U systems which reasonably can be modeled as simple-geometry, single-unit systems. Sixty-seven critical experiments of uranium highly enriched in {sup 233}U, including 57 aqueous solution, thermal-energy systems and 10 metal, fast-energy systems, were modeled. These experiments include 41 cylindrical and 26 spherical cores, and 41 reflected and 26 unreflected systems. No experiments were found for intermediate-neutron-energy ranges, or with interstitial non-hydrogenous materials typical of waste systems, mixed {sup 233}U and plutonium, or reflectors such as steel, lead, or concrete. No simple geometry experiments were found with cubic or annular cores, or approximating infinite sea systems. Calculations were performed with various tools and methodologies. Nine cross-section libraries, based on ENDF/B-IV, -V, or -VI.2, or on Hansen-Roach source data, were used with cross-section processing methods of MCNP or SCALE. The k{sub eff} calculations were performed with neutral-particle transport and Monte Carlo methods of criticality codes DANT, MCNP 4A, and KENO Va.

  9. Measurement of 233U fission spectrum-averaged cross sections for some threshold reactions

    The 233U fission spectrum-averaged cross sections for twelve threshold reactions were measured relative to the average cross section of 0.688 ± 0.040 mb for the 27Al(n,α)24Na reaction. The reference value was obtained by calculation using the energy dependent cross section in the Japanese Evaluated Nuclear Data Library (JENDL) Dosimetry File and the Watt-type fission spectrum in ENDF/B-VI. General agreement was seen between the measured and the calculated fission-spectrum averaged cross sections. However, there exist discrepancies of more than 10% between the measured and the calculated average cross sections for the 24Mg(n,p)24Na, 47Ti(n,p)47Sc, and 64Zn(n,p)64Cu reactions. The tendencies in the calculated-to-measured ratios are similar to those for 235U fission spectrum-averaged cross sections the authors previously measured. The measured average cross sections were also applied for the spectrum adjustment of the 233U fission neutrons using the Neutron Unfolding Package Code (NEUPAC). The adjusted spectrum is close to the Watt-type fission spectrum of 233U within the uncertainties of the obtained spectrum, although there exist some fluctuations in the ratio spectrum of the adjusted to the Watt-type

  10. Update of 233U, 229-232Th and 230-233Pa Fission Data

    The influence of the 235U(n,f) and 239Pu(n,f) prompt fission neutron spectra (PFNS) on modeling of integral benchmarks was estimated to be significant. For 233U(n,f) PFNS similar sensitivities could be envisaged. For the variety of Th/U fuels and systems, ranging from metal fast to deep thermal solutions, large positive/negative swings in calculated Keff can be expected. Th/U fuelled core criticality calculations would be sensitive to the modelled soft tail of fission neutrons or deficiency of hard tail fission neutrons, as revealed for U and Pu fuels. The deficiency of the 233U(nth,f) PFNS, adopted for the ENDF/B-VII.0. could be traced back to the 'propagation' of calculated 235U(nth,f) PFNS shape at En= 0.5 MeV. At higher energies, average energies of PFNS coincide only at ∼5 MeV, at other En the average energies and spectra shapes are drastically different. However, it might be argued that the response of the criticality benchmark calculations for the 233U thermal and fast systems would be similar to that observed for the PFNS of 239Pu. Our approach allowed to solve the longstanding problem of inconsistency of 235U integral data testing and differential prompt fission neutron spectra data, a similar approach may hold for 233U. Using modified PFNS, we may avoid arbitrary tweaking of neutron cross sections or neutron multiplicities for Th/U fuel-cycle related nuclides (233U, 229,230,231,232Th and 230,231,232,233Pa) to compensate the ill-defined shape of 233U PFNS. For metal fast benchmarks much would depend on the inelastic scattering cross section of 233U, which should be considered rather uncertain at the moment. The unrealistic evaluations of poorly investigated cross sections related to the Th/U fuel cycle could be excluded by consistent analysis of the available fission data base. The evaluation of 229,230,231,232Th(n,f) and 230,231,232,233Pa(n,f) cross sections could be supplemented by description of surrogate and ratio surrogate fission data, coming from

  11. Neutron inelastic-scattering cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu

    Differential-neutron-emission cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu are measured between approx. = 1.0 and 3.5 MeV with the angle and magnitude detail needed to provide angle-integrated emission cross sections to approx. 232Th, 233U, 235U and 238U inelastic-scattering values, poor agreement is observed for 240Pu, and a serious discrepancy exists in the case of 239Pu

  12. The calculation of prompt fission neutron spectrum for 233U(n,f) reaction by the semi-empirical method

    Chen, Yong-Jing; Min, Jia; Liu, Ting-Jin; Shu, Neng-Chuan

    2013-01-01

    The prompt fission neutron spectra for neutron-induced fission of 233U for low energy neutrons (below 6 MeV) are calculated using the nuclear evaporation theory with a semi-empirical method, in which the partition of the total excitation energy between the fission fragments for the nth+233U fission reactions are determined with the available experimental and evaluation data. The calculated prompt fission neutron spectra agree well with the experimental data. The proportions of high- energy ou...

  13. Simultaneous measurement of the neutron capture and fission yields of {sup 233}U

    Berthoumieux, E.; Abbondanno, U.; Aerts, G.; Alvarez, H.A.; Alvarez-Velarde, F.A.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Calvino, F.; Calviani, M.; Cano Ott, D.; Capote, R.; Carrapic, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fujii, K.; Furman, W.; Goncalves, I.; Gonzalez-Romero, E.; Gramegna, F.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Jericha, E.; Kappeler, F.; Kadi, Y.; Karadimos, D.; Karamanis, D.; Kerveno, M.; Koehler, P.; Kossionides, E.; Krticka, M.; Lampoudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O' Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Pigni, M.T.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Praena, J.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Santos, C.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wiescher, M.; Wisshak, K

    2008-07-01

    We have measured the neutron capture and fission cross section of {sup 233}U at the neutron time-of-flight facility n-TOF at CERN in the energy range from 1 eV to 1 MeV with high accuracy by using a high performance 4{pi} BaF{sub 2} Total Absorption Calorimeter (TAC) as a detection device. The method, based on the shape analysis of the TAC energy response, allowing to disentangle between {gamma}'s originating from fission and capture will be presented as well as the first very preliminary results. (authors)

  14. Simultaneous measurement of the neutron capture and fission yields of 233U

    We have measured the neutron capture and fission cross section of 233U at the neutron time-of-flight facility n-TOF at CERN in the energy range from 1 eV to 1 MeV with high accuracy by using a high performance 4π BaF2 Total Absorption Calorimeter (TAC) as a detection device. The method, based on the shape analysis of the TAC energy response, allowing to disentangle between γ's originating from fission and capture will be presented as well as the first very preliminary results. (authors)

  15. Fabrication of zero power reactor fuel elements containing 233U3O8 powder

    Oak Ridge National Laboratory, under contract with Argonne National Laboratory, completed the fabrication of 1743 fuel elements for use in their Zero Power Reactor. The contract also included recovery of 20 kg of 233U from rejected elements. This report describes the steps associated with conversion of purified uranyl nitrate (as solution) to U3O8 powder (suitable for fuel) and subsequent charging, sealing, decontamination, and testing of the fuel elements (packets) preparatory to shipment. The nuclear safety, radiation exposures, and quality assurance aspects of the program are discussed

  16. Shutdown margin for high conversion BWRs operating in Th-{sup 233}U fuel cycle

    Shaposhnik, Y., E-mail: shaposhy@bgu.ac.il [NRCN – Nuclear Research Center Negev, POB 9001, Beer Sheva 84190 (Israel); Department of Nuclear Engineering, Ben-Gurion University of the Negev, POB 653, Beer Sheva 84105 (Israel); Shwageraus, E. [Department of Nuclear Engineering, Ben-Gurion University of the Negev, POB 653, Beer Sheva 84105 (Israel); Elias, E. [Faculty of Mechanical Engineering, Technion – Israel Institute of Technology, Technion City 32000, Haifa (Israel)

    2014-09-15

    Highlights: • BWR core operating in a closed self-sustainable Th-{sup 233}U fuel cycle. • Shutdown Margin in Th-RBWR design. • Fully coupled MC with fuel depletion and thermo-hydraulic feedback modules. • Thermal–hydraulic analysis includes MCPR observation. - Abstract: Several reactivity control system design options are explored in order to satisfy shutdown margin (SDM) requirements in a high conversion BWRs operating in Th-{sup 233}U fuel cycle (Th-RBWR). The studied core has an axially heterogeneous fuel assembly structure with a single fissile zone “sandwiched” between two fertile blanket zones. The utilization of an originally suggested RBWR Y-shape control rod in Th-RBWR is shown to be insufficient for maintaining adequate SDM to balance the high negative reactivity feedbacks, while maintaining fuel breeding potential, core power rating, and minimum Critical Power Ratio (CPR). Implementation of alternative reactivity control materials, reducing axial leakage through non-uniform enrichment distribution, use of burnable poisons, reducing number of pins as well as increasing pin diameter are also shown to be incapable of meeting the SDM requirements. Instead, an alternative assembly design, based on Rod Cluster Control Assembly with absorber rods was investigated. This design matches the reference ABWR core power and has adequate shutdown margin. The new concept was modeled as a single three-dimensional fuel assembly having reflective radial boundaries, using the BGCore system, which consists of the MCNP code coupled with fuel depletion and thermo-hydraulic feedback modules.

  17. Assessment of the available 233U cross-section evaluations in the calculation of critical benchmark experiments

    In this report we investigate the adequacy of the available 233U cross-section data for calculation of experimental critical systems. The 233U evaluations provided in two evaluated nuclear data libraries, the U.S. Data Bank [ENDF/B (Evaluated Nuclear Data Files)] and the Japanese Data Bank [JENDL (Japanese Evaluated Nuclear Data Library)] are examined. Calculations were performed for six thermal and ten fast experimental critical systems using the Sn transport XSDRNPM code. To verify the performance of the 233U cross-section data for nuclear criticality safety application in which the neutron energy spectrum is predominantly in the epithermal energy range, calculations of four numerical benchmark systems with energy spectra in the intermediate energy range were done. These calculations serve only as an indication of the difference in calculated results that may be expected when the two 233U cross-section evaluations are used for problems with neutron spectra in the intermediate energy range. Additionally, comparisons of experimental and calculated central fission rate ratios were also made. The study has suggested that an ad hoc 233U evaluation based on the JENDL library provides better overall results for both fast and thermal experimental critical systems

  18. Assessment of the Available (Sup 233)U Cross Sections Evaluations in the Calculation of Critical Benchmark Experiments

    Leal, L.C.

    1993-01-01

    In this report we investigate the adequacy of the available {sup 233}U cross-section data for calculation of experimental critical systems. The {sup 233}U evaluations provided in two evaluated nuclear data libraries, the U. S. Data Bank [ENDF/B (Evaluated Nuclear Data Files)] and the Japanese Data Bank [JENDL (Japanese Evaluated Nuclear Data Library)] are examined. Calculations were performed for six thermal and ten fast experimental critical systems using the Sn transport XSDRNPM code. To verify the performance of the {sup 233}U cross-section data for nuclear criticality safety application in which the neutron energy spectrum is predominantly in the epithermal energy range, calculations of four numerical benchmark systems with energy spectra in the intermediate energy range were done. These calculations serve only as an indication of the difference in calculated results that may be expected when the two {sup 233}U cross-section evaluations are used for problems with neutron spectra in the intermediate energy range. Additionally, comparisons of experimental and calculated central fission rate ratios were also made. The study has suggested that an ad hoc {sup 233}U evaluation based on the JENDL library provides better overall results for both fast and thermal experimental critical systems.

  19. 233U mass yield measurements around and within the symmetry region with the ILL Lohengrin spectrometer

    Chebboubi, A.; Kessedjian, G.; Sage, C.; Bernard, D.; Blanc, A.; Faust, H.; Köster, U.; Litaize, O.; Mutti, P.; Serot, O.

    2016-03-01

    The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

  20. Shutdown Margin for High Conversion BWRs Operating in Th-233U Fuel Cycle

    Shaposhnik, Yaniv; Elias, Ezra

    2013-01-01

    Several reactivity control system design options are explored in order to satisfy shutdown margin (SDM) requirements in a high conversion BWRs operating in Th-233U fuel cycle (Th-RBWR). The studied has an axially heterogeneous fuel assembly structure with a single fissile zone sandwiched between two fertile blanket zones. The utilization of an originally suggested RBWR Y-shape control rod in Th-RBWR is shown to be insufficient for maintaining adequate SDM to balance the high negative reactivity feedbacks, while maintaining fuel breeding potential, core power rating, and minimum Critical Power Ratio (CPR). Instead, an alternative assembly design, also relying on heterogeneous fuel zoning, is proposed for achieving fissile inventory ratio (FIR) above unity, adequate SDM and meeting minimum CPR limit at thermal core output matching the ABWR power. The new concept was modeled as a single 3-dimensional fuel assembly having reflective radial boundaries, using the BGCore system, which consists of the MCNP code coupl...

  1. 233U mass yield measurements around and within the symmetry region with the ILL Lohengrin spectrometer

    Chebboubi A.

    2016-01-01

    Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

  2. Health physics experience during recovery of 233U from irradiated thorium rods

    Recovery of 233U from the irradiated thorium rods (46 numbers) received from Bhabha Atomic Research Centre (BARC) was carried out successfully at Reprocessing Development Laboratory (RDL), Indira Gandhi Centre for Atomic Research (IGCAR). The reprocessing was done in five stages viz., charging of fuel rods into charging flask, decladding, dissolution, solvent extraction and reconversion. The complete operation, being first of its kind, undertaken at the centre needed extensive health physics surveillance and supervision at each stage of the operation. The operational radiation protection methods followed and the experience gained during this initial campaign in area and personnel monitoring, air monitoring and contamination are discussed. The results of routine stack monitoring and analysis of waste generated in the process are given. Special operations like decommissioning of the glove box are highlighted. A brief description of unusual occurrences is also given. (author)

  3. Aerosols generated by 239PU and 233U droplets burning in air

    The inhalation hazards of radioactive aerosols produced by the explosive disruption and subsequent combustion of metallic plutonium in air are not adequately understood. Results of a study to determine whether uranium can be substituted for plutonium in such a situation in which experiments were performed under identical conditions with laser-ignited, single, freely falling droplets of 239Pu and 233U are reported. The total amounts of aerosol produced were studied quantitatively as a function of time during the combustion. Also, particle size distributions of selected aerosols were studied with aerodynamic particle separation techniques. Results showed that the ultimate quantity of aerosols, their final particle size distributions, and depositions as a function of time are not identical mainly because of the different vapor pressures of the metals, and the unlike degrees of violence of the explosions of the droplets

  4. 233U fuel production and 30-year utilization without reprocessing and refuelling using heavy water coolant

    This study examines the physics of a thorium fuel cycle based on generating the initial fissile (233U) fuel inventory in a Deuterium-Tritium fusion device and on operating a 600 MWth fission reactor. For both phases of the fuel cycle, the fuel form is an aqueous slurry consisting of thorium oxide micro-particles dispersed into heavy water. The slurry is the fuel carrier and the coolant. After 180 full power days in the fusion driven device, the fuel enrichment is 1.4%. The enrichments is defined as the ratio between the fissile actinides mass and the total actinides mass. After the removal of fission products, the 1.4% enriched slurry thorium-uranium fuel can be used for longer than 30 full power years in a 600 MWth critical reactor core, without adding any fissile material. The critical reactor has three zones: inner fissile, central fertile, and outer reflector. (author)

  5. Batch extraction studies for the recovery of 233U from thoria irradiated in PHWR

    Batch equilibrium studies were carried out to optimise the extraction parameters for the recovery of 233U from thoria irradiated in PHWR. The thorium concentration and the acidity of the feed was adjusted to ca. 100 g/l and 4 M nitric acid respectively. The concentration of uranium was in the range of 1.4 g/L and it contained long lived fission product like 144Ce-144Pr, 134Cs, 137Cs, 106Ru-106Rh, 105Eu, 154Eu, 90Sr-90Y and 125Sb. 3% TBP in dodecane was used as the solvent. Four stages of batch extraction was followed by a single scrub stage of 4 M nitric acid. The scrubbed organic was stripped with 0.01 M HNO3 thrice. The stripped product was concentrated by evaporation and passed through a cation exchanger to remove the residual thorium. The results of the studies are discussed in detail. (author)

  6. Investigation of the fission yields of the fast neutron-induced fission of 233U

    As a stars, a survey of the different methods of investigations of the fission product yields and the experimental data status have been studied, showing advantages and shortcomings for the different approaches. An overview of the existing models for the fission product distributions has been as well intended. The main part of this thesis was the measurement of the independent yields of the fast neutron-induced fission of233U, never investigated before this work. The experiment has been carried out using the mass separator OSIRIS (Isotope Separator On-Line). Its integrated ion-source and its specific properties required an analysis of the delay-parameter and ionisation efficiency for each chemical species. On the other hand, this technique allows measurement of independent yields and cumulative yields for elements from Cu to Ba, covering most of the fission yield distribution. Thus, we measured about 180 independent yields from Zn (Z=30) to Sr (Z=38) in the mass range A=74-99 and from Pd (Z=46) to Ba (Z=56) in the mass range A=113-147, including many isomeric states. An additional experiment using direct γ-spectroscopy of aggregates of fission products was used to determine more than 50 cumulative yields of element with half-life from 15 min to a several days. All experimental data have been compared to estimates from a semi-empirical model, to calculated values and to evaluated values from the European library JEF 2.2. Furthermore, a study of both thermal and fast neutron-induced fission of 233U measured at Studsvik, the comparison of the OSIRIS and LOHENGRIN facilities and the trends in new data for the Reactors Physics have been discussed. (author)

  7. Breeding of 233U in the thorium–uranium fuel cycle in VVER reactors using heavy water

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the 233U–232Th oxide fuel of water-moderated reactors with variable water composition (D2O, H2O) that ensures breeding of the 233U and 235U isotopes. The method is comparatively simple to implement

  8. Health physics surveillance during recovery of 233U from irradiated thorium rods at reprocessing development lab, IGCAR

    Second campaign for the recovery of 233U from the irradiated rods from CIRUS and DHRUVA reactors at BARC, was carried out successfully at Reprocessing Development Laboratory (RDL) at Indira Gandhi Centre for Atomic Research (IGCAR). Health physics surveillance was provided all through the operation. The operational radiation protection methods followed and the experience gained during the campaign are discussed in this paper. (author)

  9. Breeding of {sup 233}U in the thorium–uranium fuel cycle in VVER reactors using heavy water

    Marshalkin, V. E., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics (VNIIEF) (Russian Federation)

    2015-12-15

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the {sup 233}U–{sup 232}Th oxide fuel of water-moderated reactors with variable water composition (D{sub 2}O, H{sub 2}O) that ensures breeding of the {sup 233}U and {sup 235}U isotopes. The method is comparatively simple to implement.

  10. Application of the SCALE TSUNAMI Tools for the Validation of Criticality Safety Calculations Involving 233U

    Mueller, Don [ORNL; Rearden, Bradley T [ORNL; Hollenbach, Daniel F [ORNL

    2009-02-01

    The Radiochemical Development Facility at Oak Ridge National Laboratory has been storing solid materials containing 233U for decades. Preparations are under way to process these materials into a form that is inherently safe from a nuclear criticality safety perspective. This will be accomplished by down-blending the {sup 233}U materials with depleted or natural uranium. At the request of the U.S. Department of Energy, a study has been performed using the SCALE sensitivity and uncertainty analysis tools to demonstrate how these tools could be used to validate nuclear criticality safety calculations of selected process and storage configurations. ISOTEK nuclear criticality safety staff provided four models that are representative of the criticality safety calculations for which validation will be needed. The SCALE TSUNAMI-1D and TSUNAMI-3D sequences were used to generate energy-dependent k{sub eff} sensitivity profiles for each nuclide and reaction present in the four safety analysis models, also referred to as the applications, and in a large set of critical experiments. The SCALE TSUNAMI-IP module was used together with the sensitivity profiles and the cross-section uncertainty data contained in the SCALE covariance data files to propagate the cross-section uncertainties ({Delta}{sigma}/{sigma}) to k{sub eff} uncertainties ({Delta}k/k) for each application model. The SCALE TSUNAMI-IP module was also used to evaluate the similarity of each of the 672 critical experiments with each application. Results of the uncertainty analysis and similarity assessment are presented in this report. A total of 142 experiments were judged to be similar to application 1, and 68 experiments were judged to be similar to application 2. None of the 672 experiments were judged to be adequately similar to applications 3 and 4. Discussion of the uncertainty analysis and similarity assessment is provided for each of the four applications. Example upper subcritical limits (USLs) were

  11. Measurement of neutron capture and fission cross sections of 233U in the resonance region

    Tsekhanovich I.

    2012-02-01

    Full Text Available In the framework of studies concerning new fuel cycles and nuclear wastes incineration experimental data of the α ratio between capture and fission cross sections of 233U reactions play an important role in the Th/U cycle. The safety evaluation and the detailed performance assessment for the generation IV nuclear-energy system based on 232Th cycle strongly depend on this ratio. Since the current data are scarce and sometimes contradictory, new experimental studies are required. The measurement will take place at the neutron time-of-flight facility GELINA at Geel, designed to perform neutron cross section measurements with high incident neutron-energy resolution. A dedicated high efficiency fission ionization chamber (IC as fission fragment detector and six C6D6 liquid scintilators sensitive to γ-rays and neutrons will be used. The method, based on the IC energy response study, allowing to distinguish between gammas originating from fission and capture, in the resonance region, will be presented.

  12. Numbers of prompt neutrons per fission for U233, U235, Pu239, and Cf252

    An absolute measurement of #-v#, the average number of prompt neutrons emitted per fission, is being made for the spontaneous fission of Cf262. The relative values of #-v# are being measured for neutron-induced fission of U233, U235, and Pu239, and are being compared with the spontaneous fission #-v# of Cf252. Neutrons with energies between thermal and 15 MeV are used. Particular emphasis is put on studying the dependence of #-v# on the incident neutron energy. A fission counter containing the appropriate isotope is placed in the centre of a large cadmium-loade d liquid scintillator. Through the fissionable isotope is passed a collimated beam of neutrons. Fission events, identified by pulses from the fission counter, open an electronic gate between the large liquid scintillator and a scaler. Scintillator pulses due to capture in the scintillating solution of thermalized fission neutrons are counted during the gate. The fission neutrons are detected almost independently of energy and with very high efficiency. With this technique values of #-v# to an accuracy of 1 % are expected. (author)

  13. Measurements of neutron induced capture and fission reactions on $^{233}$ U (EAR1)

    The $^{233}$U plays the essential role of ssile nucleus in the Th-U fuel cycle, which has been proposed as a safer and cleaner alternative to the U-Pu fuel cycle. Considered the scarce data available to assess the capture cross section, a measurement was proposed and successfully performed at the n_TOF facility at CERN using the 4$\\pi$ Total Absorp- tion Calorimeter (TAC). The measurement was extremely dicult due to the need to accurately distinguish between capture and fission $\\gamma$-rays without any additional discrim-ination tool and the measured capture cross section showed a signicant disagreement in magnitude when compared with the ENDF/B-VII.1 library despite the agreement in shape. We propose a new measurement that is aimed at providing a higher level of dis-crimination between competing nuclear reactions, to extend the neutron energy range and to obtain more precise and accurate data, thus fullling the demands of the "NEA High Priority Nuclear Data Request List". The setup is envisaged as a combin...

  14. Thermoionic emission characteristics of uranium with application to its determination by MSID technique using 233U tracer

    Experimental details of the uranium determination in geological samples (50-1500 ppm range) by mass spectrometric isotope dilution technique (MSID) employing 233U tracer are presented. For this purpose the thermoionic emission characteristics of uranium in various filament arrangements like simple plane, filament boat, double, are studied and the most efficient one selected for the isotope dilution analysis. The various experimental procedures involved in the MSID like sample dissolution, chemical separation and mass spectrometric analysis are developed and optimised. The experimental results on the uranium determination by MSID with 233U tracer yielded precision and accuracy of 0,5% and 1% respectively. The importance of the sampling in the precise and accuracy determination of uranium in geological samples, where it is heterogeneously distributed, is discussed. (author)

  15. Qualification and initial characterization of a high-purity 233U spike for use in uranium analyses

    Several high-purity 233U items potentially useful as isotope dilution mass spectrometry standards for safeguards, non-proliferation, and nuclear forensics measurements are identified and rescued from downblending. By preserving the supply of 233U materials of different pedigree for use as source materials for certified reference materials (CRMs), it is ensured that the safeguards community has high quality uranium isotopic standards required for calibration of the analytical instruments. One of the items identified as a source material for a high-purity CRM is characterized for the uranium isotope-amount ratios using thermal ionization mass spectrometry (TIMS). Additional verification measurements on this material using quadrupole inductively coupled plasma mass spectrometry (ICPMS) are also performed. As a result, the comparison of the ICPMS uranium isotope-amount ratios with the TIMS data, with much smaller uncertainties, validated the ICPMS measurement practices. ICPMS is proposed for the initial screening of the purity of items in the rescue campaign

  16. Amster: a molten-salt reactor concept generating its own 233U and incinerating transuranium elements

    In the coming century, sustainable development of atomic energy will require the development of new types of reactors able to exceed the limits of the existing reactor types, be it in terms of optimum use of natural fuel resources, reduction in the production of long-lived radioactive waste, or economic competitiveness. Of the various candidates with the potential to meet these needs, molten-salt reactors are particularly attractive, in the light of the benefits they offer, arising from two fundamental features: - A liquid fuel does away with the constraints inherent in solid fuel, leading to a drastic simplification of the fuel cycle, in particular making in possible to carry out on-line pyrochemical reprocessing; - Thorium cycle and thermal spectrum breeding. The MSBR concept proposed by ORNL in the 1970's thus gave a breeding factor of 1.06, with a doubling time of about 25 years. However, given the tight neutron balance of the thorium cycle (the η of 233U is about 2.3), MSBR performance is only possible if there are strict constraints set on the in-line reprocessing unit: all the 233Pa must be removed from the core so that it can decay on the 233U in no more than about ten days (or at least 15 tonnes of salt to be extracted from the core daily), and the absorbing fission products, in particular the rare earths, must be extracted in about fifty days. With the AMSTER MSR concept, which we initially developed for incinerating transuranium elements, we looked to reduce the mass of salt to be reprocessed in order to minimise the size and complexity of the reprocessing unit coupled to the reactor, and the quantity of transuranium elements sent for disposal, as this is directly proportional to the mass of salt reprocessed for extraction of the fission products. Given that breeding was not an absolute necessity, because the reactor can be started by incinerating the transuranium elements from the spent fuel assemblies of current reactors, or if necessary by loading

  17. Neutronic optimization in high conversion Th-233U fuel assembly with simulated annealing

    This paper reports on fuel design optimization of a PWR operating in a self sustainable Th-233U fuel cycle. Monte Carlo simulated annealing method was used in order to identify the fuel assembly configuration with the most attractive breeding performance. In previous studies, it was shown that breeding may be achieved by employing heterogeneous Seed-Blanket fuel geometry. The arrangement of seed and blanket pins within the assemblies may be determined by varying the designed parameters based on basic reactor physics phenomena which affect breeding. However, the amount of free parameters may still prove to be prohibitively large in order to systematically explore the design space for optimal solution. Therefore, the Monte Carlo annealing algorithm for neutronic optimization is applied in order to identify the most favorable design. The objective of simulated annealing optimization is to find a set of design parameters, which maximizes some given performance function (such as relative period of net breeding) under specified constraints (such as fuel cycle length). The first objective of the study was to demonstrate that the simulated annealing optimization algorithm will lead to the same fuel pins arrangement as was obtained in the previous studies which used only basic physics phenomena as guidance for optimization. In the second part of this work, the simulated annealing method was used to optimize fuel pins arrangement in much larger fuel assembly, where the basic physics intuition does not yield clearly optimal configuration. The simulated annealing method was found to be very efficient in selecting the optimal design in both cases. In the future, this method will be used for optimization of fuel assembly design with larger number of free parameters in order to determine the most favorable trade-off between the breeding performance and core average power density. (authors)

  18. Cross sections and neutron yields for U233, U235 and Pu239 at 2200 m/sec

    The experimental information on the 2200 m/sec values for σabs, σf, α, ν and η for 233U , 235U and 23 been collected and discussed. The values will later be used in an evaluation of a 'best' set of data. In appendix the isotopic abundances of the uranium isotopes are discussed and also the alpha activities of the uranium isotopes and Pu-239

  19. Study of (n,p) and (n,α) cross-sections for 232Th, 231Pa, 233U isotopes

    The study of neutron induced reaction cross-sections in the charged particle emission in this energy region will help us to understand the energy dependence of activation cross-sections in detail, thereby providing a complete database that will lead to better understanding of mechanisms of the nuclear reactions. The present study describes nuclear model calculations of (n,p) and (n,α) reaction cross-sections for 232Th, 231Pa and 233U isotopes

  20. Investigation of tritium and 233U breeding in a fission-fusion hybrid reactor fuelling with ThO2

    In the world, thorium reserves are three times more than natural Uranium reserves. It is planned in the near future that nuclear reactors will use thorium as a fuel. Thorium is not a fissile isotope because it doesn't make fission with thermal neutrons so it could be converted to 233U isotope which has very high quality fission cross-section with thermal neutrons. 233U isotope can be used in present LWRs as an enrichment fuel. In the fusion reactors, tritium is the most important fossil fuel. Because tritium is not natural isotope, it has to be produced in the reactor. The purpose of this work is to investigate the tritium and 233U breeding in a fission-fusion hybrid reactor fuelling with ThO2 for Δt=10 days during a reactor operation period in five years. The neutronic analysis is performed on an experimental hybrid blanket geometry. In the center of the hybrid blanket, there is a line neutron source in a cylindrical cavity, which simulates the fusion plasma chamber where high energy neutrons (14.1 MeV) are produced. The conventional fusion reaction delivers the external neutron source for blankets following, 2D + 3T →? 4He (3.5 MeV) + n (14.1 MeV). (1) The fuel zone made up of natural-ThO2 fuel and it is cooled with different coolants. In this work, five different moderator materials, which are Li2BeF4, LiF-NaF-BeF2, Li20Sn80, natural Lithium and Li17Pb83, are used as coolants. The radial reflector, called tritium breeding zones, is made of different Lithium compounds and graphite in sandwich structure. In the work, eight different Lithium compounds were used as tritium breeders in the tritium breeding zones, which are Li3N, Li2O, Li2O2, Li2TiO3, Li4SiO3, Li2ZrO3, LiBr and LiH. Neutron transport calculations are conducted in spherical geometry with the help of SCALE4.4A SYSTEM by solving the Boltzmann transport equation with code CSAS and XSDRNPM, under consideration of unresolved and resolved resonances, in S8-P3 approximation with Gaussian quadratures using

  1. Fractional independent yields of 141La and 142La from thermal-neutron-induced fission of 233U

    The fractional independent yields of 141La and 142La from thermal-neutron-induced fission of 233U were found to be 0.026 +- 0.006 and 0.068 +- 0.010, respectively. These yields are consistent with charge distributions for which σ = 0.56 +- 0.02 and 0.52 +- 0.02, respectively. These results are in good agreement with similar yields measured for fission of 235U, but not with those from fission of 249Cf. (author)

  2. Fission, total and neutron capture cross section measurements at ORELA for {sup 233}U, {sup 27}Al and natural chlorine

    Guber, K.H.; Spencer, R.R.; Leal, L.C.; Larson, D.C.; Santos, G. Dos; Harvey, J.A.; Hill, N.W.

    1998-08-01

    The authors have made use of the Oak Ridge Electron Linear Accelerator (ORELA) to measure the fission cross section of {sup 233}U in the neutron energy range of 0.36 eV to {approximately} 700 keV. This paper reports integral data and average cross sections. In addition they measured the total neutron cross section of {sup 27}Al and natural chlorine, as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV.

  3. Investigation of the fission yields of the fast neutron-induced fission of {sup 233}U; Mesure de la distribution en masse et en charge des produits de la fission rapide de l'{sup 233}U

    Galy, J

    1999-09-01

    As a stars, a survey of the different methods of investigations of the fission product yields and the experimental data status have been studied, showing advantages and shortcomings for the different approaches. An overview of the existing models for the fission product distributions has been as well intended. The main part of this thesis was the measurement of the independent yields of the fast neutron-induced fission of{sup 233}U, never investigated before this work. The experiment has been carried out using the mass separator OSIRIS (Isotope Separator On-Line). Its integrated ion-source and its specific properties required an analysis of the delay-parameter and ionisation efficiency for each chemical species. On the other hand, this technique allows measurement of independent yields and cumulative yields for elements from Cu to Ba, covering most of the fission yield distribution. Thus, we measured about 180 independent yields from Zn (Z=30) to Sr (Z=38) in the mass range A=74-99 and from Pd (Z=46) to Ba (Z=56) in the mass range A=113-147, including many isomeric states. An additional experiment using direct {gamma}-spectroscopy of aggregates of fission products was used to determine more than 50 cumulative yields of element with half-life from 15 min to a several days. All experimental data have been compared to estimates from a semi-empirical model, to calculated values and to evaluated values from the European library JEF 2.2. Furthermore, a study of both thermal and fast neutron-induced fission of {sup 233}U measured at Studsvik, the comparison of the OSIRIS and LOHENGRIN facilities and the trends in new data for the Reactors Physics have been discussed. (author)

  4. Fission cross-section measurements on 233U and minor actinides at the CERN n-TOF facility

    Neutron-induced fission cross-sections of minor actinides have been measured at the white neutron source n-TOF at CERN, Geneva. The studied isotopes include 233U, interesting for Th/U based nuclear fuel cycles, 241,243Am and 245Cm, relevant for transmutation and waste reduction studies in new generation fast reactors (Gen-IV) or Accelerator Driven Systems. The measurements take advantage of the unique features of the n-TOF facility, namely the wide energy range, the high instantaneous neutron flux and the low background. Results for the involved isotopes are reported from ∼30 meV to around 1 MeV neutron energy. The measurements have been performed with a dedicated Fission Ionization Chamber (FIC), relative to the standard cross-section of the 235U fission reaction, measured simultaneously with the same detector. Results are here reported. (authors)

  5. Multiplicity and energy of neutrons from {sup 233}U(n{sub th},f) fission fragments

    Nishio, Katsuhisa; Kimura, Itsuro; Nakagome, Yoshihiro [Kyoto Univ. (Japan)

    1998-03-01

    The correlation between fission fragments and prompt neutrons from the reaction {sup 233}U(n{sub th},f) was measured with improved accuracy. The results determined the neutron multiplicity and emission energy as a function of fragment mass and total kinetic energy. The average energy as a function of fragment mass followed a nearly symmetric distribution centered about the equal mass-split and formed a remarkable contrast with the saw-tooth distribution of the average neutron multiplicity. The neutron multiplicity from the specified fragment decreases linearly with total kinetic energy, and the slope of multiplicity with kinetic energy had the minimum value at about 130 u. The level density parameter versus mass determined from the neutron data showed a saw-tooth structure with the pronounced minimum at about 128 and generally followed the formula by Gilbert and Cameron, suggesting that the neutron emission process was very much affected by the shell-effect of the fission fragment. (author)

  6. Basic characterization of 233U: Determination of age and 232U content using sector field ICP-MS, gamma spectrometry and alpha spectrometry

    The possibility to determine the age, i.e. the time since the last chemical separation, of 233U was studied using two fundamentally different measurement techniques: inductively coupled plasma mass spectrometry (ICP-MS) and gamma spectrometry. Moreover, the isotope ratio 232U/233U was measured using both alpha spectrometry and gamma spectrometry. For the two materials analysed, all measurement results were in agreement, i.e. consistent within the combined uncertainties. One of the materials was also measured using gamma spectrometry under field conditions. This measurement was also in agreement with the other results on this material

  7. Cost-based optimizations of power density and target-blanket modularity for {sup 232}Th/{sup 233}U-based ADEP

    Krakowski, R.A.

    1995-07-01

    A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a {sup 232}Th/{sup 233}U fuel cycle and a molten-salt (LiF/BeF{sub 2}/ThF{sub 3}) fluid-fuel primary system. Simplified neutron-balance, accelerator, reactor-core, chemical-processing, and balance-of-plant models are combined parametrically with a simplified costing model. The main focus of this model is to examine trade offs related to fission power density, reactor-core modularity, {sup 233}U breeding rate, and fission product transmutation capacity.

  8. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement

  9. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium-uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement.

  10. Measurement of the $^{233}$U neutron capture cross section at the n_TOF facility at CERN

    Carrapiço, Carlos; Berthoumieux, Eric; Gonçalves, Isabel; Gunsing, Frank

    2012-12-12

    The Thorium-Uranium (Th-U) fuel cycle has been envisaged as an alternative to the Uranium-Plutonium (U-Pu) fuel cycle for electricity generation using nuclear power reactors. Indeed, thorium can be used as a nuclear fuel, and several studies and R&D programs seem to provide evidence on the sustainability of the Th-U fuel cycle, due to (i) the natural abundance of Thorium, (ii) the improved proliferation resistance offered by the Th-U fuel cycle relative to the U-Pu fuel cycle, (iii) the better neutronics performance of the Th-U fuel cycle throughout the whole neutron energy range compared to the U-Pu fuel cycle, (iv) the lower radiotoxicity of the generated spent fuel in reactors with Th-U fuel cycle and, consequently (v) better economics and public acceptance of the reactors operated using the Th-U fuel cycle compared to those using the U-Pu fuel cycle (prior to the Generation IV nuclear reactors). In a nuclear reactor operated using the Th-U fuel cycle, $^{233}$U is a key nuclide governing the neutr...

  11. Dissolution of unirradiated UO{sub 2} and UO{sub 2} doped with {sup 233}U under reducing conditions

    Ollila, K. [VTT Processes (Finland); Oversby, V.M. [VMO Konsult (Sweden)

    2005-01-01

    Experiments have been conducted to determine an upper limit to the dissolution rate of UO{sub 2} under reducing conditions appropriate to those in a geologic repository for spent fuel disposal in Finland and Sweden. Test duration ranged from 52 to 140 days. The total amount of U recovered in each test was converted into a dissolution rate per year for the sample. The dissolution rate was then used to calculate an expected lifetime for the samples under the test conditions. The dissolution rate did not depend on the length of the testing period. Rather, the dissolution rate appeared to decrease as the samples were exposed to sequential testing periods. This indicates that the results are still influenced by transient effects such as high-energy surface sites, which implies that the dissolution rates measured are upper limits. The sample lifetimes calculated from the last two testing periods, which had a total of 269 days, ranged from 7 to 10 million years. There was no indication of an effect of alpha radiolysis on the dissolution rate results for samples with doping levels of 0, 5, and 10% {sup 233}U.

  12. Evaluation of the thermal-neutron constants for 233U, 235U, 239Pu and 241Pu

    A consistent set of best values of the 2200 meter/second neutron cross sections, Westcott g-factors, and fission neutron yields for 233U, 235U, 239Pu and 241Pu are presented. A least squares fitting program, LSF, is used to obtain the best fit and to estimate the sensitivity of these fissile parameters to the quoted uncertainties in experimental data. The half-lives of the uranium and plutonium nuclides have been evaluated and these have been used to reassess the significant experimental data. The latest revision of the spontaneous fission neutron yield anti nu, of 252Cf and the foil thickness corrections to the fission neutron yield ratios of fissile nuclei to 252Cf are included. These lead to greater consistency in the data used for anti nu (252Cf). Similarly, the 234U half-life as revised leads to improved consistency in the 235U fission cross section. Comparison is made with the values from ENDF/B-V and other evaluations

  13. Coulomb effects in isobaric cold fission from reactions 233U(nth,f), 235U(nth,f), 239Pu(nth,f) and 252Cf(sf)

    Montoya, Modesto

    2014-01-01

    The Coulomb effect hypothesis, formerly used to interpret fluctuations in the curve of maximal total kinetic energy as a function of light fragment mass in reactions 233U(nth,f), 235U(nth,f) and 239Pu(nth,f), is confirmed in high kinetic energy as well as in low excitation energy windows, respectively. Data from reactions 233U(nth,f), 235U(nth,f), 239Pu(nth,f) and 252Cf(sf) show that, between two isobaric fragmentations with similar Q-values, the more asymmetric charge split reaches the higher value of total kinetic energy. Moreover, in isobaric charge splits with different Q-values, similar preference for asymmetrical fragmentations is observed in low excitation energy windows.

  14. Neutron-induced fission cross-section of 233U in the energy range 0.5n< 20 MeV

    The neutron-induced fission cross-section of 233U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of 235U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against α -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of ∼ 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the 233U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

  15. Neutron-induced fission cross-section of {sup 233}U in the energy range 0.5

    Belloni, F.; Milazzo, P.M.; Abbondanno, U.; Fujii, K.; Moreau, C. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Calviani, M. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare (INFN), Legnaro (Italy); CERN, Geneva (Switzerland); Colonna, N.; Marrone, S.; Meaze, M.H.; Tagliente, G.; Terlizzi, R. [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); Mastinu, P.; Gramegna, F. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [CEA, Irfu, Gif-sur-Yvette (France); Alvarez, H.; Cano-Ott, D.; Duran, I.; Embid-Segura, M.; Gonzalez-Romero, E.; Paradela, C. [Univ. de Santiago de Compostela, Santiago (Spain); Alvarez-Velarde, F.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz, Lodz (Poland); Audouin, L.; Dillmann, I.; Heil, M.; Kaeppeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K. [Inst. fuer Kernphysik, Karlsruhe Inst. of Technology, Campus Nord, Karlsruhe (Germany); Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H.; Pigni, M.T. [Technische Univ. Wien, Atominstitut der Oesterreichischen Univ., Wien (Austria); Baumann, P.; David, S.; Kerveno, M.; Lukic, S.; Rudolf, G. [Centre National de la Recherche Scientifique/IN2P3 - IReS, Strasbourg (France); Becvar, F.; Krticka, M. [Charles Univ., Faculty of Mathematics and Physics, Prague (Czech Republic); Calvino, F.; Cortes, G.; Poch, A.; Pretel, C. [Univ. Politecnica de Catalunya, Barcelona (Spain); Capote, R. [NAPC/Nuclear Data Section, International Atomic Energy Agency, Vienna (Austria); Univ. de Sevilla, Sevilla (Spain); Carrapico, C.; Goncalves, I.; Salgado, J.; Santos, C.; Tavora, L.; Vaz, P. [Inst. Tecnologico e Nuclear, Lisbon (Portugal)] [and others

    2011-01-15

    The neutron-induced fission cross-section of {sup 233}U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of {sup 235}U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against {alpha} -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of {approx} 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the {sup 233}U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

  16. Development of a method for recovery of 233U from thorium oxalate cake in reconversion step of reprocessing of irradiated thorium rods

    A method is developed for the selective leaching of 233U from a thorium oxalate cake. The leaching capacity of ammonium carbonate and nitric acid have been investigated, showing that (NH4)2CO3 leads to higher recovery. The maximum leaching efficiency is obtained using 0.5% ammonium carbonate, with a minimal thorium pick-up. A uranium recovery of 94% is obtained after three consecutive contact experiments in carbonate media, with minimal thorium uptake in the leachate. This process was applied to an actual plant stream, allowing the reduction of the 233U α-activity from 5.64 to 0.3 μCi/g of thorium oxalate cake. (author)

  17. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    Lane, Taylor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  18. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f) and 252Cf(sf)

    Val’ski G.V.; Gagarski A.M.; Shcherbakov O.A.; Vorobyev A.S.; Petrov G.A.

    2010-01-01

    A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn’t de...

  19. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the {sup 233}U isotope in the VVER reactors using thorium and heavy water

    Marshalkin, V. E., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics (Russian Federation)

    2015-12-15

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D{sub 2}O, H{sub 2}O) is proposed. The method is characterized by efficient breeding of the {sup 233}U isotope and safe reactor operation and is comparatively simple to implement.

  20. Monte Carlo analysis of direct measurements of the fission neutron yield per absorption by 233U and 235U of monochromatic neutrons

    Monte Carlo analysis of the measurements of Smith et al. of the number of fission neutrons produced per neutron absorbed, eta, for 2200 m/sec neutrons absorbed by 233U and 235U yields: eta2200233 = 2.2993 +- 0.0082 and eta2200235 = 2.0777 +- 0.0064. The standard deviations include Monte Carlo, cross section, and experimental uncertainties. The Monte Carlo analysis was confirmed by calculating measured quantities used by the experimentalists in determining eta2200

  1. Measurement of neutron induced fission of {sup 235}U, {sup 233}U and {sup 245}Cm with the FIC detector at the CERN n-TOF facility

    Calviani, M.; Karadimos, D.; Abbondanno, U.; Aerts, G.; Alvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrapic, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fujii, K.; Furman, W.; Goncalves, I.; Gonzalez-Romero, E.; Gramegna, F.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Jericha, E.; Kappeler, F.; Kadi, Y.; Karamanis, D.; Kerveno, M.; Koehler, P.; Kossionides, E.; Krticka, M.; Lampoudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O' Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Pigni, M.T.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Praena, J.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Santos, C.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wiescher, M.; Wisshak, K

    2008-07-01

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the {sup 235}U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as {sup 235}U, {sup 233}U and {sup 245}Cm in the energy range from 0.050 eV to about 2 MeV. These results for {sup 235}U, {sup 233}U and {sup 245}Cm show results consistent with databases in the resonance region, with no normalization required for {sup 233}U. In the case of {sup 245}Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  2. Measurement of neutron induced fission of 235U, 233U and 245Cm with the FIC detector at the CERN n-TOF facility

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the 235U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as 235U, 233U and 245Cm in the energy range from 0.050 eV to about 2 MeV. These results for 235U, 233U and 245Cm show results consistent with databases in the resonance region, with no normalization required for 233U. In the case of 245Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  3. Track 8: health and radiological applications. Isotopes and radiation: general. 3. Extraction of 229Th from 233U for Medical Research Applications

    The use of 213Bi as an alpha emitter is being explored by the medical research community for treatment of a variety of cancers. An example is the protocol for the treatment of acute myeloid leukemia developed by Memorial Sloan-Kettering Cancer Center. The humanized antibody HuM195 is used to target a surface protein on the cancer cell. Bismuth is linked to the antibody with a chelating agent. Because of the high linear energy transfer and short range of the emitted alpha particle, there is a high probability of killing the targeted cell without exposing other parts of the body to a large dose of radiation. Bismuth-213 is extracted as the decay product of 225Ac, which in turn is extracted as a decay product of 229Th. A limited supply of 229Th, itself a product of the decay of 233U, has been separated by Oak Ridge National Laboratory (ORNL). About 95 mCi was separated from waste materials remaining from the processing of 233U in the 1970's. An additional 15 mCi was separated directly from 233U in 1998. In June 2000, the secretary of energy announced a program to separate additional thorium to support Phase II human trials at Sloan-Kettering and growing research programs at other institutions. This paper describes a project that will extract an additional 70 mCi of 229Th from a 3.3-kg batch of 233U sent to ORNL by Mound Laboratories in 1996. This project requires a process and location that would support the sustained extraction of thorium from 233U. The flow-sheet used for the initial processing of uranium was adopted, with several modifications. The 233U is currently stored in the ORNL Radiochemical Development Facility (RDF). The adjacent Radioactive Materials Analytical Laboratory (RMAL) was selected as the processing site because of the availability of both trained radiochemical staff and the type of hot cells suitable for processing uranium with increasingly high levels of 232U. Decay products from this isotope, especially 208Tl, add to the dose associated with

  4. Dissolution rates of unirradiated UO2, UO2 doped with 233U, and spent fuel under normal atmospheric conditions and under reducing conditions using an isotope dilution method

    The experimental results given in this report allow us to draw the following conclusions. 1) Tests using unirradiated fuel pellet materials from two different manufacturers gave very different dissolution rates under air atmosphere testing. Tests for fragments of pellets from different pellets made by the same manufacturer gave good agreement. This indicates that details of the manufacturing process have a large effect on the behavior of unirradiated UO2 in dissolution experiments. Care must be taken in interpreting differences in results obtained in different laboratories because the results may be affected by manufacturing effects. 2) Long-term tests under air atmosphere have begun to show the effects of precipitation. Further testing will be needed before the samples reach steady state. 3) Testing of unirradiated UO2 in systems containing an iron strip to produce reducing conditions gave [U] less than detection limits (235U added as spike was recovered, indicating that 90% of the spike had precipitated onto the solid sample or the iron strip. 9) Tests of UO2 pellet materials containing 233U to provide an alpha decay activity similar to that expected for spent fuel 3000 and 10,000 years after disposal showed that the pellet materials behaved as expected under air atmosphere conditions, showing that the manufacturing method was successful. 10) Early testing of the 233U-doped materials under reducing conditions showed relatively rapid (30 minute) dissolution of small amounts of U at the start of the puff test procedure. Results of analyses of an acidified fraction of the same solutions after 1 or 2 weeks holding indicate that the solutions were inhomogeneous, indicating the presence of colloidal material or small grains of solid. 11) Samples from the 233U-doped tests initially indicated dissolution of solid during the first week of testing, with some indication of more rapid dissolution of the material with the higher doping. 12) The second cycle of testing of the

  5. Evaluation of fission cross sections and covariances for {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu

    Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan); Matsunobu, Hiroyuki [Data Engineering, Inc. (Japan); Murata, Toru [AITEL Corporation, Tokyo (JP)] [and others

    2000-02-01

    A simultaneous evaluation code SOK (Simultaneous evaluation on KALMAN) has been developed, which is a least-squares fitting program to absolute and relative measurements. The SOK code was employed to evaluate the fission cross sections of {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu for the evaluated nuclear data library JENDL-3.3. Procedures of the simultaneous evaluation and the experimental database of the fission cross sections are described. The fission cross sections obtained were compared with evaluated values given in JENDL-3.2 and ENDF/B-VI. (author)

  6. Neutron-induced fission cross sections of 233U and 243Am in the energy range 0.5 Mev En 20 MeV @ n_TOF

    Belloni, F; Milazzo, P M; Calviani, M; Colonna, N; Mastinu, P; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Baumann, P; Becvár, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, E; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fujii, K; Furman, W; Goncalves, I; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Koehler, P; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mengoni, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vazl, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2011-01-01

    Neutron-induced fission cross-sections of actinides have been recently measured at the neutron time of flight facility n_TOF at CERN in the frame of a research project involving isotopes relevant for nuclear astrophysics and nuclear technologies. Fission fragments are detected by a gas counter with good discrimination between nuclear fission products and background events. Neutron-induced fission cross-sections of 233U and 243Am were determined relative to 235U. The present paper reports the results obtained at neutron energies between 0.5 and 20 MeV.

  7. A 233U/236U/242Pu/244Pu spike for isotopic and isotope dilution analysis by mass spectrometry with internal calibration

    The Khlopin Radium Institute prepared on behalf of the IAEA a synthetic mixture of 233U, 236U, 242Pu and 244Pu isotopes. The isotopic composition and elemental concentration of uranium and plutonium were certified on the basis of analyses done by four laboratories of the IAEA Network, using mass spectrometry with internal standardization. The certified values for 233U/236U ratio and the 236U chemical concentration have a coefficient of variation of 0.05%. The latter is fixed by the uncertainty in the 235U/238U ratio of NBS500 used as internal standard. The coefficients of variation of the 244Pu/242Pu ratio and the 242Pu chemical concentration are respectively 0.10% and 0.16% and limited by the uncertainty in the 240Pu/239Pu ratio of NBS947. This four isotope mixture was used as an internal standard as well as a spike, to analyze 30 batches of LWR spent fuel solutions. The repeatability of the mass spectrometric measurements have a coefficient of variation of 0.025% for the uranium concentration, and of 0.039% for the plutonium concentration. The spiking and treatment errors had a coefficient of variation of 0.048%. (author). Refs, figs and tabs

  8. The energy amplifier: A solid-phase, accelerator driven, sub critical Th/233 U breeder for nuclear energy production with minimal actinide waste

    We describe a hybrid system consisting of a medium current (1-10 mA), medium energy (1 GeV) proton accelerator feeding a subcritical assembly consisting of Thorium (or another fertile element) and a moderator medium (e.g. light water). Under conditions of moderate neutron flux (1014 ncm-2), we show by a computer simulation that a stable equilibrium evolves whereby the concentration of fissile 233U which is bred from Thorium is stable at about 1.3%. The 233U produces energy by fission and is continuously regenerated in-situ without resorting to any chemical separation. It is shown that the energy produced is several times larger than the energy required to power the proton accelerator, hence the name Energy Amplifier that we have chosen for that system. We have paid particular attention to the question of toxicity and show that this system will result in very small quantities of Plutonium and higher actinide waste. We also show the composition of actinides produced makes this system particularly resistant to nuclear weapons proliferation. This safe subcritical system is based on an abundant and inexpensive resource which is natural Thorium and can be built using present day technology

  9. Collective and single-particle excitations in the heavy deformable nuclei 234U, 233U, 231Th, 230Pa and 232Pa

    In this thesis five heavy deformed isotopes from the mass region A≥230, namely 234U, 233U, 231Th, 230Pa and 232Pa, were investigated by means of deuteron-induced neutron transfer reactions. The even-even isotope 234U has been studied with the 4π-γ-spectrometer MINIBALL at the Cologne Tandem accelerator. Excited nuclei in the isotope 234U were produced using the reaction 235U(d,t) at a beam energy of 11 MeV. The target thickness was 3.5 mg/cm2. The analysis of the γγ-coincidence data yielded a reinterpretation of the level scheme in 12 cases. Considering its decay characteristics, the 4+ state at an excitation energy of 1886.7 keV is a potential candidate for a two-phonon vibrational state. The isotopes 233U, 231Th, 230Pa and 232Pa were investigated at the Munich Q3D spectrometer. For each isotope an angular distribution with angles between 5 and 45 were measured. In all four cases the energy of the polarized deuteron beam (vector polarization of 80%) was 22 MeV. As targets 234U (160 μg/cm2), 230Th (140 μg/cm2) and 231Pa (140 μg/cm2) were used. The experimental angular distributions were compared to results of DWBA calculations. For the odd isotope 233U spin and parity for 33 states are assigned and in the other odd isotope 231Th 22 assignments are made. The excitation spectra of the two odd-odd isotopes 230Pa and 232Pa were investigated for the first time. For the isotope 230Pa 63 states below an excitation energy of 1.5 MeV are identified. Based on the new experimental data the Nilsson configuration of the ground state is either 1/2[530]p-5/2[633]n or 1/2[530]p+3/2[631]n. In addition 12 rotational bands are proposed and from this six values for the GM splitting energy are deduced as well as two new values for the Newby shift. In the other odd-odd isotope 232Pa 40 states below an excitation energy of 850 keV are observed and suggestions for the groundstate band and its GM partner are made. From this one GM splitting energy was determined.

  10. Study of the mass, isotopic and kinetic energy distributions of the 233U(nth, f) and 241Pu(nth, f) fission products measured at the Lohengrin mass spectrometer (ILL)

    Fission product yields are significant nuclear data for neutronic simulations. The purpose of this work is to improve fission yield knowledge for two fissile nuclei: 241Pu and 233U. Those are respectively involved in the uranium and thorium nuclear fuel cycle. The measurements are performed at the Lohengrin mass spectrometer of the Institut Laue-Langevin (ILL) located in Grenoble. The spectrometer is combined with an ionization chamber to measure mass yields of 241Pu and 233U and with a gamma spectrometry set-up to determine isotopic yields of 233U. A new analysis method of experimental data has been developed in order to control systematics and to reduce experimental biases. For the first time, the experimental variance-covariance matrix of our measured fission yields could be deduced. (author)

  11. Determination of the extraction efficiency for $^{233}$U source $\\alpha$-recoil ions from the MLL buffer-gas stopping cell

    von der Wense, Lars; Laatiaoui, Mustapha; Thirolf, Peter G

    2016-01-01

    Following the $\\alpha$ decay of $^{233}$U, $^{229}$Th recoil ions are shown to be extracted in a significant amount from the MLL buffer-gas stopping cell. The produced recoil ions and subsequent daughter nuclei are mass purified with the help of a customized quadrupole mass spectrometer. The combined extraction and mass-purification efficiency for $^{229}$Th$^{3+}$ is determined via MCP-based measurements and via the direct detection of the $^{229}$Th $\\alpha$ decay. A large value of $(10\\pm2)$\\% for the combined extraction and mass-purification efficiency of $^{229}$Th$^{3+}$ is obtained at a mass resolution of about 1 u/e. In addition to $^{229}$Th, also other $\\alpha$-recoil ions of the $^{233,232}$U decay chains are addressed.

  12. Investigation of the prompt neutron emission mechanism in low energy fission of 235,233U(nth, f and 252Cf(sf

    Val’ski G.V.

    2010-10-01

    Full Text Available A series of experiments has been performed to measure prompt neutron angular and energy distributions from thermal neutron-induced fission of 235,233U in correlation with the fission fragments. These distributions have been analyzed with the assumption of neutron isotropic emission from accelerated fission fragments. The performed analysis demonstrates that all obtained results can be described within 5% accuracy using this assumption. This discrepancy is approximately constant and doesn’t depend on fragment mass and the total kinetic energy (TKE. Some minor peculiarities of angular distribution may be interpreted as a result of anisotropy of the fission neutron angular distribution in the fragment center-of-mass system.

  13. Measurements of the yields of the light fission products from the reaction 233U(nsub(th),f) by a ionization chamber

    The aim of this thesis was to develop a new measuring apparature and measuring method which allows to study together with the mass separator 'Lohengrin' at the high flux reactor in Grenoble in realizable measurement times detailedly the unknown mass, nuclear charge, and energy distributions of the fission products resulting from the fission of 233U with thermal neutrons. First the yields and the energy distributions of the masses, thereafter the yields and the energy distributions of the isobaric nuclear charges of the light fission products in the mass range 79<=Asub(L)<=106 are measured. The measuring method for the determination of the mass yields consists of a energy measurement of the fission products separated in the mass separator by a ionization chamber. The isobaric nuclear charges and their yields are determined by the nuclear-charge-specific energy-loss method from the residual-energy spectra behind an absorber. (orig./HSI)

  14. Measurement of Neutron Induced Fission of 235U, 233U and 245Cm with the FIC Detector at the CERN n()TOF Facility

    A series of measurements of neutron induced fission cross section of various TRU isotopes have been performed at the CERN n()TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n()TOF neutron flux, the well known cross section of the 235U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as 235U, 233U and 245Cm in the energy range from 0.050 eV to about 2 MeV.

  15. Fission Cross-section Measurements of (233)U, (245)Cm and (241,243)Am at CERN n_TOF Facility

    Calviani, M; Andriamonje, S; Chiaveri, E; Vlachoudis, V; Colonna, N; Meaze, M H; Marrone, S; Tagliente, G; Terlizzi, R; Belloni, F; Abbondanno, U; Fujii, K; Milazzo, P M; Moreau, C; Aerts, G; Berthoumieux, E; Dridi, W; Gunsing, F; Pancin, J; Perrot, L; Plukis, A; Alvarez, H; Duran, I; Paradela, C; Alvarez-Velarde, F; Cano-Ott, D; Gonzalez-Romero, E; Guerrero, C; Martinez, T; Villamarin, D; Vicente, M C; Andrzejewski, J; Marganiec, J; Assimakopoulos, P; Karadimos, D; Karamanis, D; Papachristodoulou, C; Patronis, N; Audouin, L; David, S; Ferrant, L; Isaev, S; Stephan, C; Tassan-Got, L; Badurek, G; Jericha, E; Leeb, H; Oberhummer, H; Pigni, M T; Baumann, P; Kerveno, M; Lukic, S; Rudolf, G; Becvar, F; Krticka, M; Calvino, F; Capote, R; Carrillo De Albornoz, A; Marques, L; Salgado, J; Tavora, L; Vaz, P; Cennini, P; Dahlfors, M; Ferrari, A; Gramegna, F; Herrera-Martinez, A; Kadi, Y; Mastinu, P; Praena, J; Sarchiapone, L; Wendler, H; Chepel, V; Ferreira-Marques, R; Goncalves, I; Lindote, A; Lopes, I; Neves, F; Cortes, G; Poch, A; Pretel, C; Couture, A; Cox, J; O'brien, S; Wiescher, M; Dillman, I; Heil, M; Kappeler, F; Mosconi, M; Plag, R; Voss, F; Walter, S; Wisshak, K; Dolfini, R; Rubbia, C; Domingo-Pardo, C; Tain, J L; Eleftheriadis, C; Savvidis, I; Frais-Koelbl, H; Griesmayer, E; Furman, W; Konovalov, V; Goverdovski, A; Ketlerov, V; Haas, B; Haight, R; Reifarth, R; Igashira, M; Koehler, P; Kossionides, E; Lampoudis, C; Lozano, M; Quesada, J; Massimi, C; Vannini, G; Mengoni, A; Oshima, M; Papadopoulos, C; Vlastou, R; Pavlik, A; Pavlopoulos, P; Plompen, A; Rullhusen, P; Rauscher, T; Rosetti, M; Ventura, A

    2011-01-01

    Neutron-induced fission cross-sections of minor actinides have been measured using the n_TOF white neutron source at CERN, Geneva, as part of a large experimental program aiming at collecting new data relevant for nuclear astrophysics and for the design of advanced reactor systems. The measurements at n_TOF take advantage of the innovative features of the n_TOF facility, namely the wide energy range, high instantaneous neutron flux and good energy resolution. Final results on the fission cross-section of 233U, 245Cm and 243Am from thermal to 20 MeV are here reported, together with preliminary results for 241Am. The measurement have been performed with a dedicated Fast Ionization Chamber (FIC), a fission fragment detector with a very high efficiency, relative to the very well known cross-section of 235U, measured simultaneously with the same detector.

  16. Monte Carlo analysis of direct measurements of the thermal eta (.025 eV) for 233U and 235U (LWBR development program)

    Significant inconsistencies have been observed between measured values of eta and of ν, which are related by eta = ν/(1+α). In support of the LWBR program, manganese bath measurements of eta of 233U and 235U employing monoenergetic 0.025 eV neutrons were analyzed using Monte Carlo methods and ENDF-4 cross sections. The calculated (eta*/eta2200) ratios are essentially independent of the values assumed for eta2200. The standard deviation on our calculated values of eta includes Monte Carlo, cross section, and experimental uncertainties. The Monte Carlo analysis was confirmed by calculating measured quantities used by the experimentalists in their reduction of eta* to eta. (4 figures, 12 tables) (U.S.)

  17. Measurement of the generation ratio of 233U and the average radiation capture cross section of 232Th with 232ThO2 irradiated by fast neutrons

    Background: Thorium-Uranium cycle plays an important role in the future's power production technology. Nuclear data involved are urgently needed for engineering design and other purposes since there are obvious differences between the existing evaluated data. Macroscopic neutron integral experiment can be used as a good tool to survey the confusion. Purpose: Macroscopic neutron integral experiment based on radioactive method was carried out to measure the generation ratio of 233U nuclide and the average radiation capture cross section of 232Th while a ThO2 sample was irradiated by fast neutrons leakage from a fast critical facility. We expect that these data can be used as a reference for the research of Th-U cycle. Methods: Radiation capture reactions of 232Th nuclides occur when the nuclides are irradiated by neutrons. 233U nuclides will be generated after two cascade decays by emitting beta rays from the activation products, which are 233Th nuclides. The ThO2 sample was prepared as a slice of 20 mm×10 mm from 0.743 36-g ThO2 powders of 99.9% enriched. The neutron flux was measured by activation method which was 4.07x109 cm-2·s-1 at the sample's irradiation position while the facility worked at the power level of 180 watts. The leakage neutrons' energy distribution was calculated by MC method and it is very close to the fission spectrum with the averaged energy of 1.42 MeV. After irradiation and then a period of cooling time the gamma rays emitted from the sample were measured by an HPGe spectrometer which had been pre-calibrated. From these data the activity of 233Pa was calculated and then the generation ratio of 233U and the average radiation capture cross section of 232Th were calculated. The measured average radiation capture cross section was compared with the cross sections calculated based on the ENDFB-VH.1, CENDL-3.1, JENDL-4.0, BROND2.2 databases. Results: The measured generation ratio of 233U was 4.01×10-12 with an uncertainty of 6

  18. R-MATRIX RESONANCE ANALYSIS AND STATISTICAL PROPERTIES OF THE RESONANCE PARAMETERS OF 233U IN THE NEUTRON ENERGY RANGE FROM THERMAL TO 600 eV

    Leal, L.C.

    2001-02-27

    The R-matrix resonance analysis of experimental neutron transmission and cross sections of {sup 233}U, with the Reich-Moore Bayesian code SAMMY, was extended up to the neutron energy of 600 eV by taking advantage of new high resolution neutron transmission and fission cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA). The experimental data base is described. In addition to the microscopic data (time-of-flight measurements of transmission and cross sections), some experimental and evaluated integral quantities were included in the data base. Tabulated and graphical comparisons between the experimental data and the SAMMY calculated cross sections are given. The ability of the calculated cross sections to reproduce the effective multiplication factors k{sub eff} for various thermal, intermediate, and fast systems was tested. The statistical properties of the resonance parameters were examined and recommended values of the average s-wave resonance parameters are given.

  19. Mass balance analysis of Th-233U based MSR (Molten-Salt Reactor) cycle (THORIMS-NES) transferred from present U-Pu based LWRs (Light Water Reactor)

    Nuclear power can play a substantial role in countering global warming. There are still unsolved problems such as safety, nuclear proliferation, radioactive-waste under using U-Pu system. Transition from U-Pu LWR (Light Water Reactor) system to Th-233U MSR (Molten-Salt Reactor) system has been analysed in view of the utilization of fissile in form of Pu fuel salt applying the simplified FREGAT process to the spent fuel of LWR. AMSB (Accelerator Molten-Salt Breeder) was also applied as a fissile producer. All fissile in spent fuel can be used by Th-U MSR system so as not to remain storage of spent fuel after retirement of LWR system. The maximum capacity of Th-U MSR system will reach to about 20 x 103 GWe. However storage of spent fuel will remain for the case of rapid growth of Th-U MSR system even though the maximum capacity is large enough. AMSB will start operation about 20 years after the beginning of Th-U MSR system but the timing can be greatly advanced with the scenario of LWR system. Th-U MSR system can be implemented by using the fissile material in spent fuel from LWRs. Detailed assessment of other materials, performance of facilities, strategies of non-proliferation will be needed for the future improvement.

  20. The effect of dissolved hydrogen on the dissolution of 233U doped UO2(s) high burn-up spent fuel and MOX fuel

    In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of 233U doped UO2(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H2 pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H2 pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO2, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10-6/yr - 10-8/yr with a recommended value of 4x10-7/yr for dissolved hydrogen concentrations above 10-3 M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO2 and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB

  1. Fusion hybrids for generation of advanced (231Pa+232U+233U+234U)-fuel in closed (U-Pu-Th)-fuel cycle

    Technology of controlled thermonuclear fusion (CTF) is traditionally regarded as a practically inexhaustible energy source. However, development, mastering, broad deployment of fast breeder reactors and closure of nuclear fuel cycle (NFC) can also extend fuel base of nuclear power industry (NPI) up to practically unlimited scales. Under these conditions, it seems reasonable to introduce into a circle of the CTF-related studies the works directed towards solving some principal problems which can appear in a large-scale NPI in closed NFC. The first challenge is a large scale of operations in NFC back-end that should be reduced by achieving substantially higher fuel burn-up in power nuclear reactors. The use of 231Pa-232Th-232U-233U fuel in light-water reactor (LWR) opens a possibility of principle to reach very high (about 30% HM) or even ultra-high fuel burn-up. The second challenge is a potential unauthorized proliferation of fissionable materials. As is known, a certain remarkable quantity of 232U being introduced into uranium fraction of nuclear fuel can produce a serious barrier against switching the fuel over to non-energy purposes. Involvement of hybrid thermonuclear reactors (HTR) into NPI structure can substantially facilitate resolving these problems. If HTR will be involved into NPI structure, then main HTR mission consists not in energy generation but in production of nuclear fuel with a certain isotope composition. The present paper analyzes some neutron-physical features in production of advanced nuclear fuels in thorium HTR blankets. The obtained results demonstrated that such a nuclear fuel may be characterized by very stable neutron-multiplying properties during full LWR operation cycle and by enhanced proliferation resistance too. The paper evaluates potential benefits from involvement of HTR with thorium blanket into the international closed NFC. (author)

  2. The effect of dissolved hydrogen on the dissolution of {sup 233}U doped UO{sub 2}(s) high burn-up spent fuel and MOX fuel

    Carbol, P. [Inst. for Transuranium Elements, Karlsruhe (Germany); Spahiu, K. (ed.) [and others

    2005-03-01

    In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of {sup 233}U doped UO{sub 2}(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H{sub 2} pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H{sub 2} pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO{sub 2}, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10{sup -6}/yr - 10{sup -8}/yr with a recommended value of 4x10{sup -7}/yr for dissolved hydrogen concentrations above 10{sup -3} M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO{sub 2} and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB.

  3. Expeditious method to determine uranium in the process control samples of chemical plant separating (233)U from thoria irradiated in power reactors.

    Kedari, C S; Kharwandikar, B K; Banerjee, K

    2016-11-01

    Analysis of U in the samples containing a significant proportion of (232)U and high concentration of Th is of great concern. Transmutation of Th in the nuclear power reactor produces a notable quantity of (232)U (half life 68.9 years) along with fissile isotope (233)U. The decay series of (232)U is initiated with (228)Th (half life 1.9 year) and it is followed by several short lived α emitting progenies, (224)Ra, (220)Rn, (216)Po, (212)Bi and (212)Po. Even at the smallest contamination of (228)Th in the sample, a very high pulse rate of α emission is obtained, which is to be counted for the radiometric determination of [U]. A commercially available anionic type of extractant Alamine®336 is used to obtain the selective extraction of U from other alpha active elements and fission products present in the sample. Experimental conditions of liquid-liquid extraction (LLE) are optimized for obtaining maximum decontamination and recovery of U in the organic phase. The effect of some interfering ionic impurities in the sample on the process of separation is investigated. Depending on the level of the concentration of U in the samples, spectrophotometry or radiometry methods are adopted for its determination after separation by LLE. Under optimized experimental conditions, i.e. 5.5M HCl in the aqueous phase and 0.27M Alamin®336 in the organic phase, the recovery of U is about 100%, the decontamination factor with respect to Th is >2000 and the extraction of fission products like (90)Sr, (144)Ce and (134,137)Cs is negligible. The detection limit for [U] using α radiometry is 10mg/L, even in presence of >100g/L of Th in the sample. Accuracy and precision for the determination of U is also assessed. Reproducibility of results is within 5%. This method shows very good agreement with the results obtained by mass spectrometry. PMID:27591623

  4. Calculation of the fission cross section for 233U and the interpretation of fragment anisotropy and fine structure in anti νsub(p) and anti Esub(k)

    The fission cross section of 233U has been calculated using a new version of the statistical model and recent data for inelastic scattering levels and fission barrier parameters. The calculation accurately reproduces the experimental fission cross section. The calculated partial cross section for fission through different saddle point states (JKπ) has been used in the explanation of structure in average number of fission prompt neutrons anti νsub(p) and average total fission fragment kinetic energy anti Esub(k) and the energy dependence of the fission fragment anisotropy

  5. Preliminary results of calculations for heavy-water nuclear-power-plant reactors employing 235U, 233U, and 232Th as a fuel and meeting requirements of a nonproliferation of nuclear weapons

    Ioffe, B. L.; Kochurov, B. P.

    2012-02-01

    A physical design is developed for a gas-cooled heavy-water nuclear reactor intended for a project of a nuclear power plant. As a fuel, the reactor would employ thorium with a small admixture of enriched uranium that contains not more than 20% of 235U. It operates in the open-cycle mode involving 233U production from thorium and its subsequent burnup. The reactor meets the conditions of a nonproliferation of nuclear weapons: the content of fissionable isotopes in uranium at all stages of the process, including the final one, is below the threshold for constructing an atomic bomb, the amount of product plutonium being extremely small.

  6. Measurement of the Neutron Capture Cross Sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm with a Total Absorption Calorimeter at n_TOF

    Beer, H; Wiescher, M; Cox, J; Rapp, W; Embid, M; Dababneh, S

    2002-01-01

    Accurate and reliable neutron capture cross section data for actinides are necessary for the poper design, safety regulation and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems (ADS). The goal of this proposal is the measurement of the neutron capture cross sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm at n_TOF with an accuracy of 5~\\%. $^{233}$U plays an essential role in the Th fuel cycle, which has been proposed as a safer and cleaner alternative to the U fuel cycle. The capture cross sections of $^{237}$Np,$^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. A high accuracy can be achieved at n_TOF in such measurements due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the facility, innovative Data Acquisition System based on flash ADCs and t...

  7. Preliminary study of the α ratio measurement, ratio of the neutron capture cross section to the fission one for 233U, on the PEREN platform. Development and study of the experimental setup

    Producing nuclear energy in order to reduce anthropic CO2 emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of 233U, ratio of the neutron capture cross section to fission one for 233U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of 233U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a 235U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of 235U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid special attention to quantify the

  8. Développement d'un dispositif expérimental dédié à la mesure des sections efficaces de capture et de fission de l'233u dans le domaine des résonances résolues

    Companis, Iulia

    2013-01-01

    233 U est le noyau fissile produit dans le cycle du combustible 232 T h/233 U qui a été proposé comme une alternative plus sûre et plus propre du cycle 238 U/239 P u. La connaissance précise de la section efficace de capture de neutrons de cet isotope est requise avec une haute précision pour la conception et le développement de réacteurs utilisant ce cycle du combustible. Les deux seuls jeux de données expérimentales fiables pour la section efficace de capture de l'233 U montrent des écarts ...

  9. Preliminary study of the {alpha} ratio measurement, ratio of the neutron capture cross section to the fission one for {sup 233}U, on the PEREN platform. Development and study of the experimental setup; Etude preliminaire de la mesure du rapport {alpha}, rapport de la section efficace moyenne de capture sur celle de fission de l'{sup 233}U, sur la plateforme PEREN. Developpement et etude du dispositif experimental

    Cognet, M.A

    2007-12-15

    Producing nuclear energy in order to reduce anthropic CO{sub 2} emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of {sup 233}U, ratio of the neutron capture cross section to fission one for {sup 233}U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of {sup 233}U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a {sup 235}U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of {sup 235}U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid

  10. The fission cross sections of 230Th, 232Th, 233U, 234U, 236U, 238U, 237Np, 239Pu and 242Pu relative 235U at 14.74 MeV neutron energy

    The measurement of the fission cross section ratios of nine isotopes relative to 235U at an average neutron energy of 14.74 MeV is described with particular attention to the determination of corrections and to sources of error. The results are compared to ENDF/B-V and to other measurements of the past decade. The ratio of the neutron induced fission cross section for these isotopes to the fission cross section for 235U are: 230Th - 0.290 +- 1.9%; 232Th - 0.191 +- 1.9%; 233U - 1.132 +- 0.7%; 234U - 0.998 +- 1.0%; 236U - 0.791 +- 1.1%; 238U - 0.587 +- 1.1%; 237Np - 1.060 +- 1.4%; 239Pu - 1.152 +- 1.1%; 242Pu - 0.967 +- 1.0%. 40 refs., 11 tabs., 9 figs

  11. Concept of a demonstrational hybrid reactor—a tokamak with molten-salt blanket for {sup 233}U fuel production: 1. Concept of a stationary Tokamak as a neutron source

    Azizov, E. A.; Gladush, G. G., E-mail: gladush@triniti.ru; Dokuka, V. N.; Khayrutdinov, R. R. [State Research Center of the Russian Federation, Troitsk Institute for Innovation and Fusion Research (Russian Federation)

    2015-12-15

    On the basis of current understanding of physical processes in tokamaks and taking into account engineering constraints, it is shown that a low-cost facility of a moderate size can be designed within the adopted concept. This facility makes it possible to achieve the power density of neutron flux which is of interest, in particular, for solving the problem of {sup 233}U fuel production from thorium. By using a molten-salt blanket, the important task of ensuring the safe operation of such a reactor in the case of possible coolant loss is accomplished. Moreover, in a hybrid reactor with the blanket based on liquid salts, the problem of periodic refueling that is difficult to perform in solid blankets can be solved.

  12. Concept of a demonstrational hybrid reactor—a tokamak with molten-salt blanket for 233U fuel production: 1. Concept of a stationary Tokamak as a neutron source

    Azizov, E. A.; Gladush, G. G.; Dokuka, V. N.; Khayrutdinov, R. R.

    2015-12-01

    On the basis of current understanding of physical processes in tokamaks and taking into account engineering constraints, it is shown that a low-cost facility of a moderate size can be designed within the adopted concept. This facility makes it possible to achieve the power density of neutron flux which is of interest, in particular, for solving the problem of 233U fuel production from thorium. By using a molten-salt blanket, the important task of ensuring the safe operation of such a reactor in the case of possible coolant loss is accomplished. Moreover, in a hybrid reactor with the blanket based on liquid salts, the problem of periodic refueling that is difficult to perform in solid blankets can be solved.

  13. Concept of a demonstrational hybrid reactor—a tokamak with molten-salt blanket for 233U fuel production: 1. Concept of a stationary Tokamak as a neutron source

    On the basis of current understanding of physical processes in tokamaks and taking into account engineering constraints, it is shown that a low-cost facility of a moderate size can be designed within the adopted concept. This facility makes it possible to achieve the power density of neutron flux which is of interest, in particular, for solving the problem of 233U fuel production from thorium. By using a molten-salt blanket, the important task of ensuring the safe operation of such a reactor in the case of possible coolant loss is accomplished. Moreover, in a hybrid reactor with the blanket based on liquid salts, the problem of periodic refueling that is difficult to perform in solid blankets can be solved

  14. Multilevel analysis of the 233U and 235U capture and fission cross-sections and statistical properties of the Kapur-Peierls-type resonance parameters for the S-wave cross-sections of the fissile isotopes

    At the 1966 Conference on Nuclear Data for Reactors, simultaneous measurements of the capture and fission cross-sections of 233U and 235U were presented. Those measurements have now been analysed with the multilevel formalism developed by Adler and Adler. To obtain consistent sets of resonance parameters the capture and fission data were least-square fitted simultaneously. This analysis was carried out to 60 eV for 233U and to 100 eV for 235U. The main purpose of this analysis was to provide a simple and precise analytical description of the very complex structure of the fission and capture cross-sections of 233U and 235U at low energy. Such an analytical description should be useful to calculate reaction rates in nuclear reactors and to compare experimental data taken with different energy resolutions or at different sample temperatures. For the low-energy resonances of 233U and 235U, the neutron width is always smaller, by at least two orders of magnitude, than the total width. Thus, the total cross-section, for those isotopes, can be approximated as the sum of the absorption cross-section and the potential scattering cross-section. Hence it is possible to compute the total cross-section from the resonance parameters obtained by fitting the fission and capture cross-sections. The total cross-section of 235U computed by this method is compared to the data from a transmission measurement done at Saclay, with the sample at 77 deg. K. The computed total cross-section of 233U is compared with transmission data obtained at Oak Ridge National Laboratory and at the Material Testing Reactor. Such comparisons between data obtained by different experimental techniques illustrate the internal consistency of the low-energy cross-sections of the two main uranium fissile isotopes. The physical interpretation of the resonance parameters is somewhat ambiguous, because such multilevel fits are by no means unique. This is particularly true for 233U since, for this nucleus, the

  15. Dissolution rates of unirradiated UO{sub 2}, UO{sub 2} doped with {sup 233}U, and spent fuel under normal atmospheric conditions and under reducing conditions using an isotope dilution method

    Ollila, Kaija [VTT Processes, Helsinki (Finland); Albinsson, Yngve [Chalmers Univ. of Technology, Goeteborg (Sweden); Oversby, Virginia [VMO Konsult, Stockholm (Sweden); Cowper, Mark [AEA Technology, Harwell (United Kingdom)

    2003-10-01

    additional meaningful data. 8) A test procedure that used several short exposures of the sample to solution - the puff test procedure - gave results that showed very little recovery of the spike solution at the end of the tests. Only 10% of the {sup 235}U added as spike was recovered, indicating that 90% of the spike had precipitated onto the solid sample or the iron strip. 9) Tests of UO{sub 2} pellet materials containing {sup 233}U to provide an alpha decay activity similar to that expected for spent fuel 3000 and 10,000 years after disposal showed that the pellet materials behaved as expected under air atmosphere conditions, showing that the manufacturing method was successful. 10) Early testing of the {sup 233}U-doped materials under reducing conditions showed relatively rapid (30 minute) dissolution of small amounts of U at the start of the puff test procedure. Results of analyses of an acidified fraction of the same solutions after 1 or 2 weeks holding indicate that the solutions were inhomogeneous, indicating the presence of colloidal material or small grains of solid. 11) Samples from the {sup 233}U-doped tests initially indicated dissolution of solid during the first week of testing, with some indication of more rapid dissolution of the material with the higher doping. 12) The second cycle of testing of the {sup 233}U-doped materials also showed dissolution occurring during the dilution stages of the puff test. The subsequent week of testing also showed small amounts of further dissolution, with hints that the doped samples were dissolving faster than the undoped samples. 13) At the end of 2 weeks of cycle 2 the remaining solution and solid was transferred to a new reaction vessel, the solution was made up to original volume, and a new dose of spike was added. The results of analyses of [U] and isotopic composition show that the measured U is that expected from dilution of the original solution plus adding the spike. 14) Samples taken during 2 weeks of testing of

  16. Etude des distributions en masse, charge nucléaire et énergie cinétique des produits de fission de l'233U(nth,f) et du 241Pu(nth,f) mesurées auprès du spectromètre de masse Lohengrin (ILL)

    Martin, Florence

    2013-01-01

    Les rendements des produits de fission font partie des données nucléaires sur lesquellesreposent les simulations neutroniques. L’objectif de cette thèse est d’apporter de nouvellesmesures de rendements de fission de deux noyaux fissiles : le 241Pu et l’233U. Ces noyauxappartiennent respectivement au cycle du combustible de l’uranium et à celui du thorium.Ces mesures ont été réalisées auprès du spectromètre de masse Lohengrin de l’InstitutLaue Langevin (ILL) à Grenoble. Le spectromètre est com...

  17. Macroeconomic regimes

    Baele, L.T.M.; Bekaert, G.R.J.; Cho, S.; Inghelbrecht, K.; Moreno, A.

    2015-01-01

    A New-Keynesian macro-model is estimated accommodating regime-switching behavior in monetary policy and macro-shocks. A key to our estimation strategy is the use of survey-based expectations for inflation and output. Output and inflation shocks shift to the low volatility regime around 1985 and 1990

  18. Estuary regime

    The primary aim of this research into estuary regime is to provide engineers with an improved method of predicting the long term evolutionary effects of major engineering changes in estuaries. Of specific interest to the Department of Trade and Industry's renewable energy R and D programme is the long term impact of tidal energy barrages on estuarine morphology. It is considered that the approach being taken is the most appropriate line to follow in terms of developing an applicable estuary regime predictive capability. As a consequence it is considered that any further regime model development should be complimentary to this approach. In addition to model development there is still an enormous amount of basic research required in examining sediment transport processes within the estuarine environment. Recently developed models for predicting the motion of fluidised mud on inter-tidal and sub-tidal banks, an important process within the estuarine sediment regime, requires specific field data calibration and validation. The impacts of wave action on sediment mobility on estuarine banks is a further area requiring field measurements. It is recommended that the opportunity be taken to obtain a set of measurements at a site following construction of major engineering works to provide data for future verification of a regime model. Possibilities exist, for example, on the Tees Estuary for such measurements. (author)

  19. Regime change?

    Following the 1998 nuclear tests in South Asia and later reinforced by revelations about North Korean and Iraqi nuclear activities, there has been growing concern about increasing proliferation dangers. At the same time, the prospects of radiological/nuclear terrorism are seen to be rising - since 9/11, concern over a proliferation/terrorism nexus has never been higher. In the face of this growing danger, there are urgent calls for stronger measures to strengthen the current international nuclear nonproliferation regime, including recommendations to place civilian processing of weapon-useable material under multinational control. As well, there are calls for entirely new tools, including military options. As proliferation and terrorism concerns grow, the regime is under pressure and there is a temptation to consider fundamental changes to the regime. In this context, this paper will address the following: Do we need to change the regime centered on the Treaty on the Nonproliferation of Nuclear Weapons (NPT) and the International Atomic Energy Agency (IAEA)? What improvements could ensure it will be the foundation for the proliferation resistance and physical protection needed if nuclear power grows? What will make it a viable centerpiece of future nonproliferation and counterterrorism approaches?

  20. Competition Regime

    Danilo Icaza Ortiz

    2013-01-01

    This paper is a review of the competition regime works of various authors, published under the auspices of the University of the Hemispheres and the Corporation for Studies and Publications. Analyzes the structure, the general concepts, case law taken for development. Includes comments on the usefulness of this work for the study of competition law and the contribution to the lawyers who want to practice in this branch of economic law.

  1. Competition Regime

    Danilo Icaza Ortiz

    2013-01-01

    Full Text Available This paper is a review of the competition regime works of various authors, published under the auspices of the University of the Hemispheres and the Corporation for Studies and Publications. Analyzes the structure, the general concepts, case law taken for development. Includes comments on the usefulness of this work for the study of competition law and the contribution to the lawyers who want to practice in this branch of economic law.

  2. Exchange Rate Regime Choice

    2006-01-01

    The choice of an adequate exchange rate regime proves to be a highly sensitive field within which the economic authorities present and confirm themselves. The advantages and disadvantages of fixed and flexible exchange rate regimes, which have been quite relativized from the conventional point of view, together with simultaneous, but not synchronised effects of structural and external factors, remain permanently questioned throughout a complex process of exchange rate regime decision making. ...

  3. Sustainable urban regime adjustments

    Quitzau, Maj-Britt; Jensen, Jens Stissing; Elle, Morten;

    2013-01-01

    The endogenous agency that urban governments increasingly portray by making conscious and planned efforts to adjust the regimes they operate within is currently not well captured in transition studies. There is a need to acknowledge the ambiguity of regime enactment at the urban scale. This direc...

  4. Exchange rate regime choice

    Beker Emilija

    2006-01-01

    Full Text Available The choice of an adequate exchange rate regime proves to be a highly sensitive field within which the economic authorities present and confirm themselves. The advantages and disadvantages of fixed and flexible exchange rate regimes, which have been quite relativized from the conventional point of view, together with simultaneous, but not synchronized effects of structural and external factors, remain permanently questioned throughout a complex process of exchange rate regime decision making. The paper reflects the attempt of critical identification of the key exchange rate performances with emphasis on continuous non-uniformity and (uncertainty of shelf life of a relevant choice.

  5. World Nonproliferation Regime

    Ouyang Liping; Wu Xingzuo

    2007-01-01

    2006 witnessed an intense struggle between nuclear proliferation and nonproliferation. Iran's nuclear issue and North Korea's nuclear test have cast a deep shadow over the current international nonproliferation regime. The international contest for civil nuclear development became especially fierce as global energy prices went up. Such a situation , to some extent, accelerated the pace of nuclear proliferation. Furthermore, the existing international nonproliferation regime, based upon the Nuclear Nonproliferation Treaty (NPT), was affected by loopholes, and the U.S. failed in its ambition to unite other forces to mend fences. The international community needs to come up with a comprehensive and long-term strategy to meet the demand for an effective future nonproliferation regime in a healthy nuclear order.

  6. Dimagrire in regime mediatico

    Boutaud, Jean-Jacques

    2012-01-01

    publication en italien : BOUTAUD Jean-Jacques, « Dimagrire in regime mediatico », Dietetica e semiotica. Regimi di Senso, a cura di Dario Mangano e Gianfranco Marrone, Mimesis Edizioni, Milano, 2013, p. 19-38 Il titolo può leggersi in molti modi. Per esempio: dietetica e semiotica sono due regimi di senso, uno alimentare e l'altro comunicativo, con pari dignità, dunque da paragonare fra loro. Oppure: grazie alla semiotica la dietetica appare, non più come un regime alimentare, ma come un r...

  7. Complex regimes of synchronization

    Yeldesbay, Azamat

    2014-01-01

    Synchronization is a fundamental phenomenon in nature. It can be considered as a general property of self-sustained oscillators to adjust their rhythm in the presence of an interaction. In this work we investigate complex regimes of synchronization phenomena by means of theoretical analysis, numerical modeling, as well as practical analysis of experimental data. As a subject of our investigation we consider chimera state, where due to spontaneous symmetry-breaking of an initially ho...

  8. Political Regimes and Economic Growth

    Carlos Pinho

    2009-12-01

    Full Text Available Are political regimes drivers of economic growth? While political institutions are influenced by economic development, they are in turn a key determinant of the development process. This study builds in the Neoclassical Growth theory to identify the influence of political regimes on economic development through a panel data sample of 170 countries from 1960 to 2000. Results suggest that once fixed effects are considered, the positive relationship between income per capita and political regimes measured by different democracy variables disappears.

  9. Suspended-Bed Reactor preliminary design, 233U--232Th cycle. Final report (revised)

    The preliminary design Suspended-Bed Reactor is described. Coated particles about 2 mm in diameter are used as the fuel. The coatings consist of three layers: (1) low density pyrolytic graphite, 70 μ thick, (2) silicon carbide pressure vessel, 30 μ thick, and (3) ZrC layer, 50 μ thick, to protect the pressure vessel from moisture and oxygen. The fuel kernel can be either uranium-thorium dicarbide or metal. The coated particles are suspended by helium gas (coolant) in a cluster of pressurized tubes. The upward flow of helium fluidizes the coated particles. As the flow rate increases, the bed of particles is lifted upward to the core section. The particles are restrained at the upper end of the core by a suitable screen. The overall particle density in the core is just enough for criticality condition. Should the helium flow cease, the bed in the core section will collapse, and the particles will flow downward into the section where the increased physical spacings among the tubes brings about a safe shutdown. By immersing this section of the tubes in a large graphite block to serve as a heat sink, dissipation of decay heat becomes manageable. This eliminates the need for emergency core cooling systems

  10. Critical dimensions of systems containing 235U, 239Pu, and 233U: 1986 Revision

    This report is primarily a compilation of critical data obtained from experiments performed in a number of laboratories during the period of 1945 through 1985. It supplements the Nuclear Safety Guide [Report TID-7016 (Rev. 2)] in presenting critical data on which recommendations of the Guide are based. It must be emphasized that this report gives critical data without safety factors, so it is no substitute for the Guide or for the related document, The American National Standard for Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors. Critical measurements with materials of interest in desired configurations yield information of greatest usefulness and accuracy. Where it is not feasible to obtain the desired critical data, for example, as a result of safety restrictions, subcritical data may be directly applicable, and in some cases may be extrapolated to approximate critical conditions. Critical conditions also may be approximated from the distribution of neutrons introduced into a subcritical assembly. These ''exponential experiments'' may be the only alternative where the quantity of material required is too great for a critical experiment. Calculated extensions of experimental data are included to show the nature of trends, not to substitute for results of experiments. They should be used with caution. A fundamental aim of this document is to illustrate relationships among critical data. The compilation and correlation of data for this purpose, from many measurements in a number of laboratories, require a certain amount of normalization or reduction to common terms. Frequently, for example, the effects of variations in geometry or density must be removed to show trends in data. The manner in which these alterations may be made is discussed in the early section Relations for Conversion to Standard Conditions. 195 refs

  11. 233U Breeding in a Modified Prometheus-L IFE Reactor

    Übeyli, Mustafa

    2004-01-01

    In this study. neutronic analysis of a hybrid version of the PROMETHEUS-LIFE reactor is investigated by using thorium fuels namely, ThN, ThC2 and ThF4. Calculations of neutronic data per DT fusion neutron are performed by using SCALE 4.3 Code. Despite a partial replacement of the tritium breeding zone by the fissile fuel breeding zone, tritium breeding remains still >

  12. MULTILATERAL DIPLOMACY AND INTERNATIONAL REGIMES

    BENEA Ciprian-Beniamin

    2014-12-01

    Full Text Available The history of diplomacy can by divided in three main periods: one is that of occasional diplomacy peculiar to Middle Ages, while other belong to permane diplomacy, peculiar to modern times. But this one can be divided in two parts, too: one with a bilateral character, previos to 1st World War, and one with a multilateral character, manifested especially after the end on 1st World War. This third type is the focus of present paper. And it cannot be separated from the newly international constructs: international regimes, and international organizations. International instritutions the area where international regimes are belonging to – are legal constructs which provide the formal (and legal framework for continous negotiations. They are the most visible part of the new diplomacy – the one which has a permanent character, and it has an more open face. Anyway, the most important connection has to do with the international institutions, international regimes, and multilateral international negotiations. In the era of the new diplomacy, they all have a permanent character. International institutions help international negotiations carring on; while in their turn, they provide the base for international regimes’ creation, and especially for their evolution. The international regimes’ evolution is an inseparable part of a permanent international framework. And if there is missing a permanent international framework (international organization connected to a specific regime, this regime is a difuse one, its members have only informal relations among them, while they survey each other, looking at their behavior, but they don’t have a formal relationship among them, which could help them solving their future common interests, and protect them from their common fears. International regimes are very important in the era when evrithing touches, and influences everything. In the same time, the complexity of our present world can be successfully

  13. Cloud regimes as phase transitions

    Stechmann, Samuel N.; Hottovy, Scott

    2016-06-01

    Clouds are repeatedly identified as a leading source of uncertainty in future climate predictions. Of particular importance are stratocumulus clouds, which can appear as either (i) closed cells that reflect solar radiation back to space or (ii) open cells that allow solar radiation to reach the Earth's surface. Here we show that these clouds regimes -- open versus closed cells -- fit the paradigm of a phase transition. In addition, this paradigm characterizes pockets of open cells as the interface between the open- and closed-cell regimes, and it identifies shallow cumulus clouds as a regime of higher variability. This behavior can be understood using an idealized model for the dynamics of atmospheric water as a stochastic diffusion process. With this new conceptual viewpoint, ideas from statistical mechanics could potentially be used for understanding uncertainties related to clouds in the climate system and climate predictions.

  14. Friction Regimes in the Lubricants Solid-State Regime

    Schipper, D.J.; Maathuis, O.; Dowson, D.; Taylor, C.M.; Childs, T.H.C.; Dalmaz, G.

    1995-01-01

    Friction measurements were performed in the lubricant's solid-state regime to study the transition from full-film lubrication, in which the separation is maintained by a solidified lubricant, to mixed lubrication. Special attention is paid to the influence of temperature (inlet viscosity) and roughn

  15. On the regimes of premixing

    Angelini, S.; Theofanous, T.G.; Yuen, W.W. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1998-01-01

    The conditions of the MAGICO-2000 experiment are extended to more broadly investigate the regimes of premixing, and the corresponding internal structures of mixing zones. With the help of the data and numerical simulations using the computer code PM-ALPHA, we can distinguish extremes of behavior dominated by inertia and thermal effects - we name these the inertia and thermal regimes, respectively. This is an important distinction that should guide future experiments aimed at code verification in this area. Interesting intermediate behaviors are also delineated and discussed. (author)

  16. The Choice of Monetary Regime

    Østrup, Finn

    comparisonbetween monetary regimes suggests that welfare is highest under nominalincome targeting where the nominal income target is determined to bring aboutprice stability.Keywords: Monetary regimes; fiscal policy; monetary non-neutrality.JEL classicification: E42, E61, E62.......The article examines how government spending is determined in a closedeconomy where the nominal wage is pre-set through contracts and the wage settershave perfect foresight regarding subsequent policy decisions. The monetaryregime affects government spending because: (i) with a pre-set nominal wage...

  17. Nova Scotia's offshore royalty regime

    Oil production from the Hibernia project in Newfoundland's offshore began in December 1997. It is estimated that by 2010 some 30 per cent of Canada's light oil production and as much as 5-10 per cent of its natural gas production will originate from offshore Newfoundland and Nova Scotia. The current level of investment in east coast offshore petroleum developments is the result of the magnitude of discovered and undiscovered petroleum resources in the region. Advances in offshore petroleum technology also contributed to lower development costs. Another reason for increased investment has been an efficient and predictable regulatory environment and government policies. Nova Scotia's royalty regimes and the evolution of royalty regimes for the Sable Offshore Energy project were discussed. The Offshore Petroleum Royalty Act gives Nova Scotia the ability to establish a royalty regime through regulations, or to enter into royalty agreements on a project by project basis, or to use a mix of both agreement and regulation. The philosophy underlying Nova Scotia's royalty regime is to find the right balance between industry and government's share of project revenues

  18. Friction Regimes in the Lubricants Solid-State Regime

    Schipper, D.J.; Maathuis, O.; Dowson, D; Taylor, C.M.; Childs, T.H.C.; Dalmaz, G.

    1995-01-01

    Friction measurements were performed in the lubricant's solid-state regime to study the transition from full-film lubrication, in which the separation is maintained by a solidified lubricant, to mixed lubrication. Special attention is paid to the influence of temperature (inlet viscosity) and roughness on this transition. The friction measurements showed that in the lubricants solid-state region three lubrication modes can be distinguished: A) full-film lubrication; separation is maintained b...

  19. Demystifying optimal dynamic treatment regimes.

    Moodie, Erica E M; Richardson, Thomas S; Stephens, David A

    2007-06-01

    A dynamic regime is a function that takes treatment and covariate history and baseline covariates as inputs and returns a decision to be made. Murphy (2003, Journal of the Royal Statistical Society, Series B 65, 331-366) and Robins (2004, Proceedings of the Second Seattle Symposium on Biostatistics, 189-326) have proposed models and developed semiparametric methods for making inference about the optimal regime in a multi-interval trial that provide clear advantages over traditional parametric approaches. We show that Murphy's model is a special case of Robins's and that the methods are closely related but not equivalent. Interesting features of the methods are highlighted using the Multicenter AIDS Cohort Study and through simulation. PMID:17688497

  20. The Concept of Truth Regime

    Lorna Weir

    2008-07-01

    Full Text Available “Truth regime” is a much used but little theorized concept, with the Foucauldian literature presupposing that truth in modernity is uniformly scientific/quasi-scientific and enhances power. I argue that the forms of truth characteristic of our present are wider than Foucault recognized, their relations to power more various, and their historicity more complex. The truth regime of advanced modernity is characterized by multiple, irreducible truth formulae that co-exist and sometimes vie for dominance. A truth formula stabilizes a network of elements: a relation between representation and presentation (words and things, truth and non-truth, and the place of the subject in discourse. Our contemporary truth regime comprises radically heterogeneous truthful knowledges – science, governance, religion/politics, and common culture – that have distinct histories and relations to power.

  1. The emerging climate change regime

    The emerging climate change regime--with the UN Framework Convention on Climate Change (FCCC) at its core--reflects the substantial uncertainties, high stakes and complicated politics of the greenhouse warming issue. The regime represents a hedging strategy. On the one hand, it treats climate change as a potentially serious problem, and in response, creates a long-term, evolutionary process to encourage further research, promote national planning, increase public awareness, and help create a sense of community among states. But it requires very little by way of substantive--and potentially costly--mitigation or adaptation measures. Although the FCCC parties have agreed to negotiate additional commitments, substantial progress is unlikely without further developments in science, technology, and public opinion. The FCCC encourages such developments, and is capable of evolution and growth, should the political will to take stronger international action emerge. 120 refs., 3 tabs

  2. The EU Commission consultation regime

    Quittkat, Christine; Finke, Barbara

    2008-01-01

    "The present consultation regime of the European Commission is marked by the role the Commission assigns to non-governmental actors or civil society organisations (CSOs). The Commission's documents on its policy of consultation and cooperation with external non-governmental actors reveal that a reflective approach has emerged during the 1980s, referring to a more elaborate concept of 'good governance'. The gradual extension is most noticeable in the change of terminology, from ‘consultation’ ...

  3. Contrasting Monetary Regimes in Africa

    Patrick Honohan; Stephen A. O'Connell

    1997-01-01

    In post-independence sub-Saharan Africa, institutional arrangements for monetary policy have taken a variety of forms, although the historical evolution of many African financial systems has been similar. This paper identifies five different regimes and examines how they evolved over time. It focuses on how the alternative institutional arrangements have influenced the performance of monetary policy under fiscal pressure, and concludes that, although the trend appears to be toward more flexib...

  4. The International Climate Change Regime

    Yamin, Farhana; Depledge, Joanna

    2005-01-01

    Aimed at the increasing number of policy-makers, stakeholders, researchers, and other professionals working on climate change, this volume presents a detailed description and analysis of the international regime established in 1992 to combat the threat of global climate change. It provides a comprehensive accessible guide to a high-profile area of international law and politics, covering not only the obligations and rights of countries, but ongoing climate negotiations as well.

  5. Monetary regimes in open economies

    Korpos, A.

    2006-01-01

    This thesis presents a two-country open economy framework for the analysis of strategic interactions among monetary authorities and wage bargaining institutions. From this perspective, the thesis investigates the economic consequences of replacing flexible and fixed exchange rate regimes with a monetary union, such as the European Economic and Monetary Union. It shows that fixing a currency creates a flatter Phillips curve and increases the aggressiveness of wage demands by labor unions. Comp...

  6. Disclosure regimes and corporate governance

    Wüstemann, Jens

    2004-01-01

    As there is a strong relationship of disclosure regimes and corporate governance the internationally varying distribution of information rights can be interpreted as a function of different systems of corporate governance. A disclosure system comprises all legally recognized information claims that a system of corporate governance or a financial system furnishes financial contracting parties with: Both public disclosure and disclosure via private information channels may serve value-relevant ...

  7. Exchange Rate Regimes and Location

    Ricci, Luca Antonio

    1997-01-01

    This paper investigates the effects of fixed versus flexible exchange rate regimes on location choices of firms and on the degree of specialization of countries. In a two-country two-differentiated-good monetary model, demand, supply, and monetary shocks arise after wages are set and prices are optimally chosen. The exchange rate performs then an adjustment role for firms located in the country relatively specialized in the good they produce, but it constitutes a factor of disturbance for the...

  8. Alberta oil sands royalty regime

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  9. Visibility regimes in mediatized publicness

    Samuel Mateus

    2014-12-01

    Full Text Available Considering the relationship between politics, media and publicness, this paper ponders the consequences of visibility in the political field. Identifying some of its existing regimes, it will posit that today visibility plays an ambivalent function to politics: it can simultaneously operate as a synoptic monitoring and control of politicians; and at the same time it may stand as an opportunity to build a charismatic leadership. In fact, political visibilities are now negotiated between the boundaries of private and public realms, and they can take the form of a risk, or an opportunity to build on a charismatic leadership.

  10. Twentieth century monetary regimes in Canadian perspective

    Harley, C. Knick

    2001-01-01

    Three monetary regimes - the gold standard, a regime of 'socialism in many countries' and the post-Bretton Woods regime - and difficult transitions between them have shaped the economic history of the twentieth century. The regimes consisted of coherent sets of government policies and equally importantly, the publics expectations about policy and each made different decisions about which of the trilemma of policy goals - fixed exchange rates, domestic policy independence and integrated capita...

  11. Accommodating human values in the climate regime

    Cook, Rosalind; Tauschinsky, Eljalill

    2008-01-01

    The climate regime addresses one of the most important challenges facing humankind today. However, while the environmental and economic sides of the problem are well represented, it lacks the inclusion of social and human aspects. The human rights regime, in contrast, is a regime which has been esta

  12. Measuring the effectiveness of international environmental regimes

    Helm, C.; Sprinz, D.F.

    1999-05-01

    While past research has emphasized the importance of international regimes for international governance, systematic assessments of regime effects are missing. This article derives a standardized measurement concept for the effectiveness of international environmental regimes by developing an operational rational choice calculus to evaluate actual policy simultaneously against a non-regime counterfactual and a collective optimum. Subsequently, the empirical feasibility of the measurement instrument is demonstrated by way of two international treaties regulating transboundary air pollution in Europe. The results demonstrate that the regimes indeed show positive effects - but fall substantially short of the collective optima. (orig.)

  13. Regime Jumps in Electricity Prices

    Electricity prices are known to be very volatile and subject to frequent jumps due to system breakdown, demand shocks, and inelastic supply. As many international electricity markets are in some state of deregulation, more and more participants in these markets are exposed to these stylised facts. Appropriate pricing, portfolio, and risk management models should incorporate these facts. Authors have introduced stochastic jump processes to deal with the jumps, but we argue and show that this specification might lead to problems with identifying the true mean-reversion within the process. Instead, we propose using a regime jump model that disentangles mean-reversion from jump behaviour. This model resembles more closely the true price path of electricity prices

  14. Propagation Regime of Iron Dust Flames

    Tang, Francois-David; Goroshin, Samuel; Higgins, Andrew J.

    2012-01-01

    A flame propagating through an iron-dust mixture can propagate in two asymptotic regimes. When the characteristic time of heat transfer between particles is much smaller than the characteristic time of particle combustion, the flame propagates in the continuum regime where the heat released by reacting particles can be modelled as a space-averaged function. In contrast, when the characteristic time of heat transfer is much larger than the particle reaction time, the flame can no longer be treated as a continuum due to dominating effects associated with the discrete nature of the particle reaction. The discrete regime is characterized by weak dependence of the flame speed on the oxygen concentration compared to the continuum regime. The discrete regime is observed in flames propagating through an iron dust cloud within a gas mixture containing xenon, while the continuum regime is obtained when xenon is substituted with helium.

  15. Accommodating human values in the climate regime

    Rosalind Cook

    2008-12-01

    Full Text Available The climate regime addresses one of the most important challenges facing humankind today. However, while the environmental and economic sides of the problem are well represented, it lacks the inclusion of social and human aspects. The human rights regime, in contrast, is a regime which has been established precisely to implement human values. This article ex-plains the problems of climate change in terms of human values and argues that some proce-dures from the human rights regime offer possibilities for improvement. It is submitted that through the inclusion of human rights instruments, such as individual communication, pro-gressive realisation and authoritative interpretation, the inclusion of human values into the climate regime will be facilitated. This article presents these instruments and discusses their potential for inclusion in the climate regime.

  16. US Forest Service LANDFIRE Historical Fire Regimes

    US Forest Service, Department of Agriculture — Historical fire regimes, intervals, and vegetation conditions are mapped using the Vegetation Dynamics Development Tool (VDDT). These data support fire and...

  17. Crustal stress regime in Italy

    M. Cesaro

    1997-06-01

    Full Text Available In order to obtain a reliable map of the present-day stress field in Italy, needed to better understand the active tectonic processes and to contribute to the assessment of seismic hazard, in 1992 we started to collect and analyze new data from borehole breakouts in deep oil and geothermal wells and focal mechanisms of earthquakes (2.5 < M <5 occurred in Italy between 1988 and 1995. From about 200 deep wells and 300 focal mechanisms analyzed to date, we infer that: the internal (SW sector of the Northern Apenninic arc is extending with minimum compressional stress (Shmin oriented ? ENE, while the external front is thrusting over the Adriatic foreland (Shmin ? NW-SE. The entire Southern Apennine is extending in NE direction (from the Tyrrhenian margin to the Apulian foreland and compression (in the foredeep is no longer active at the outer (NE thrust front. Between these two arcs, an abrupt change in the tectonic regime is detected with directions of horizontal stress changing by as much as 90º in the external front, around latitude 430N. Along the Ionian side of the Calabrian arc the stress directions inferred from breakouts and focal mechanisms are scattered with a hint of rotation from N-S Shmin close to the Southern Apennines, to ~ E-W directions in the Messina Strait. In Sicily, a NW-SE direction of SHmax is evident in the Hyblean foreland, parallel to the direction of plate motion between Africa and Europe. A more complex pattern of stress directions is observed in the thrust belt zone, with rotations from the regional trend (NW í directed SHmax to NE oriented SHmax. A predominant NW direction of SHmax is also detected in mainland Sicily from earthquake focal mechanisms, but no well data are available in this region. In the northern part of Sicily (Aeolian Islands a ~N-S direction of SHmax is observed.

  18. LOW DOSE MAGNESIUM SULPHATE REGIME FOR ECLAMPSIA

    Bangal V

    2009-09-01

    Full Text Available Pre- eclampsia is one of the commonest medical complications seen during pregnancy. It contributes significantly to maternal and perinatal morbidity and mortality. Dr.J.A.Pritchard in 1955, introduced magnesium sulphate for control of convulsions in eclampsia and is used worldwide. Considering the low body mass index of indian women, a low dose magnesium sulphate regime has been introduced by some authors. Present study was carried out at tertiary care centre in rural area. Fifty cases of eclampsia were randomly selected to find out the efficacy of low dose magnesium sulphate regime to control eclamptic convulsions. Maternal and perinatal outcome and magnesium toxicity were analyzed. It was observed that 86% cases responded to initial intravenous dose of 4 grams of 20% magnesium sulphate . Eight percent cases, who got recurrence of convulsion, were controlled by additional 2 grams of 20% magnesium sulphate. Six percent cases required shifting to standard Pritchard regime, as they did not respond to low dose magnesium sulphate regime. The average total dose of magnesium sulphate required for control of convulsions was 20 grams ie. 54.4% less than that of standard Pritchard regime. The maternal and perinatal morbidity and mortality in the present study werecomparable to those of standard Pritchard regime. The study did not find a single case of magnesium related toxicity with low dose magnesium sulphate regime. Low dose magnesium sulphate regime was found to be safe and effective in eclampsia.

  19. Explaining the Transition Between Exchange Rate Regimes

    Masson, Paul; RUGE-MURCIA, Francisco J.

    2003-01-01

    This paper studies the transition between exchange rate regimes using a Markov chain model with time-varying transition probabilities. The probabilities are parameterized as nonlinear functions of variables suggested by the currency crisis and optimal currency area literature. Results using annual data indicate that inflation, and to a lesser extent, output growth and trade openness help explain the exchange rate regime transition dynamics.

  20. LEGAL MATRIMONIAL REGIME IN B&H

    Boris Krešić

    2011-12-01

    Full Text Available Matrimonial regime between spouses or between extramarital partners, and between parents and children is regulated by the Family Law Act of Bosnia and Herzegovina Federation, hereinafter FLA B&HF (SG FBiH 35/05, 41/05, Family Law Act of the Republic of Srpska, hereinafter FLA RS (SG RS”54/02, 41/08 and the Family Law Act of Brčko District, hereinafter FLA BD (SG RS, 66/07. Legal rules used for the regulation of the matrimonial regime between spouses, as well as between spouses and third parties make matrimonial regime (Ponjavić, 2005, p. 361. Matrimonial regime between spouses in family legislation in Bosnia and Herzegovina (B&H is regulated in two following ways: as legal matrimonial regime and as contract matrimonial regime. Legal regime is the one which applies on spouses if not arranged otherwise prior to contracting marriage or during marriage. In this paper the author indicates the differences between the legal matrimonial regimes of the two entities as well as those between the entities and Brčko District of Bosnia and Herzegovina.

  1. Strengthening the nuclear non-proliferation regime

    Although the nuclear non-proliferation regime has enjoyed considerable success, today the regime has never been under greater threat. Three states have challenged the objectives of the NPT, and there is a technology challenge - the spread of centrifuge enrichment technology and know-how. A major issue confronting the international community is, how to deal with a determined proliferator? Despite this gloomy scenario, however, the non-proliferation regime has considerable strengths - many of which can be developed further. The regime comprises complex interacting and mutually reinforcing elements. At its centre is the NPT - with IAEA safeguards as the Treaty's verification mechanism. Important complementary elements include: restraint in the supply and the acquisition of sensitive technologies; multilateral regimes such as the CTBT and proposed FMCT; various regional and bilateral regimes; the range of security and arms control arrangements outside the nuclear area (including other WMD regimes); and the development of proliferation-resistant technologies. Especially important are political incentives and sanctions in support of non-proliferation objectives. This paper outlines some of the key issues facing the non-proliferation regime

  2. Synergies between nonproliferation regimes: A pragmatic approach

    Full text: With the recent progress in establishing international nonproliferation regimes, the question of synergies between different verification and monitoring regimes is becoming more acute. Three multilateral and universal nonproliferation organisations covering safeguards on civil nuclear materials, nuclear testing, and chemical weapons are up and running. A regime on biological weapons is under negotiation. Several regional organisations concerned with monitoring nonproliferation commitments in the nuclear field are in place; others are being established. Past discussions on synergies between these regimes have suffered from being too far-reaching. These discussions often have not reflected adequately the political difficulties of cooperation between regimes with different membership, scope and institutional set-up. This paper takes a pragmatic look at exploiting synergies and identifies some potential and real overlaps in the work between different verification regimes. It argues for a bottom-up approach and identifies building blocks for collaboration between verification regimes. By realising such, more limited potential for cooperation, the ground could be prepared for exploiting other synergies between these regimes. (author)

  3. Capacitance densitometer for flow regime identification

    Shipp, Jr., Roy L.

    1978-01-01

    This invention relates to a capacitance densitometer for determining the flow regime of a two-phase flow system. A two-element capacitance densitometer is used in conjunction with a conventional single-beam gamma densitometer to unambiguously identify the prevailing flow regime and the average density of a flowing fluid.

  4. Feasibility of a dual regime gyrotron

    The design concept of a 42/84 GHz, 500 kW, CW, dual-regime gyrotron for ECRH of plasma in an experimental Tokamak will be presented in this paper. Operation at 42 GHz is fundamental where as that in 84 GHz will be second harmonic so that a similar guidance system will be retained for dual regime operation. In this paper, the mode competition and mode selection procedures are presented for such a dual regime operation. Cold cavity design and self-consistent calculations will be carried out for power and efficiencies. (author)

  5. Framing of regimes and transition strategies

    Jensen, Jens Stissing

    2012-01-01

    This article suggests that transition strategies are always formulated in the context of specific representations of the regime and the challenges it faces. It is argued that the framing of a regime affects the envisioning of transition strategies. An analysis of the current development agenda for...... the housing construction sector in Denmark reveals the relevance and impacts of different regime framings. It is proposed that the ability to cope with framing issues as situated and political processes is at the core of the governance of transitions....

  6. Earth Regime Network Evolution Study (ERNESt)

    Menrad, Bob

    2016-01-01

    Speaker and Presenter at the Lincoln Laboratory Communications Workshop on April 5, 2016 at the Massachusetts Institute of Technology Lincoln Laboratory in Lexington, MA. A visual presentation titled Earth Regimes Network Evolution Study (ERNESt).

  7. The nuclear marketplace and the nonproliferation regime

    The development and acceptance of the international nonproliferation regime has been one of the most remarkable achievements of the postwar era. The nonproliferation regime has developed incrementally over time, often in spite of the inability of the two superpowers to come to grips with their own arms race. States otherwise zealous to protect their sovereignty have accepted international constraints on that same sovereignty where nuclear power is concerned. The challenge to the nonproliferation regime, then, is both serious and multifaceted. There is no single or overriding source of that regime's problems, nor is there a single solution. Rolling back the NNPA and ''letting the US nuclear industry compete'' make for a good slogan but will not change the seriousness of the nonproliferation challenge

  8. The Two Regimes of Postwar Shipping

    Iversen, Martin Jes; Tenold, Stig

    2014-01-01

    the bargaining that accompanied the shift from the national regime to the competitive regime. Specifically, we show that the new regime primarily accommodated the interests of private actors such as shipping companies, rather than the interests of the authorities and the trade unions.......The aim of this article is to illustrate the most important changes in the regulatory framework of the shipping sector from the 1960s to 2010, and to analyse the basis for, and effects of, these changes. In order to explain how the transformation has occurred, we use two traditional maritime...... nations—Denmark and Norway—as case studies. First, we introduce the two regimes of Danish and Norwegian shipping: ‘the national regime’ from the early 1960s to the mid-1970s; and ‘the competitive regime’, which was fully established by the middle of the 1990s and still persists. Then, we briefly sketch...

  9. FLOW REGIMES BELOW AERATORS FOR DISCHARGE TUNNELS

    MA Fei; WU Jian-hua

    2012-01-01

    The flow regimes below an aerator influence directly the air entrainment and the cavitation damage control.Based on the theoretical considerations,the experiments of the aerator for a discharge tunnel were conducted,and the relationships between the flow regime and hydraulic and geometric parameters were investigated.The results showed that,there are two kinds of threshold values for the flow regime conversions.One is Fr1-2 standing for the conversion from the fully filled cavity to the partially filled cavity,and the other is Fr2-3 which shows the change from the partially filled cavity to the net air cavity.Two empirical expressions were obtained for the conversions of the flow regimes,which can be used in the designs of the aerators.

  10. What is the economy of Ancien Regime?

    Jean-Yves Grenier

    2012-01-01

    The aim of this article is to describe the main features of the Ancien Regime economy and develop a “political economy” of European societies, particularly the French, during the central period of modernity (XVII-XVIII centuries

  11. The international climate regime: towards consolidation collapse

    This article deals with the different modalities that exist to manage a problem of collective action in the field of climate negotiation. It uses two concepts of the International Political Economy (IPE): the concept of International Regime (IR) and the concept of Hegemony and / or Leadership. The course the international negotiation has taken between 1992 (Rio Convention) and march 2001 (the US rejection of the Kyoto Protocol of 1997) leads us, first, to question the conditions of existence as well as the viability of a non-hegemonic International Regime (Part One). Then, we discuss the perspectives for the 'post - Kyoto' era. After having examined the preferences of the three most active actors in the negotiation (USA, Europe, G77 + China) combined with the leadership capacities they possess, we identify three scenarios for the future: i) anarchy, ii) an international regime under the American hegemony, iii) an international regime under the European leadership (Part Two). (author)

  12. Inflation in the warm and cold regimes

    Berera, Arjun

    2006-01-01

    It is now understood that inflation dynamics comes in two forms, isentropic or cold inflation and nonisentropic or warm inflation. In the former, inflation occurs without radiation production, whereas in the latter both radiation production and inflation occur concurrently. Recent, detailed, quantum field theory calculations have shown that many generic inflation models, including hybrid inflation, which were believed only to have cold inflation regimes, in fact have regimes of both warm and ...

  13. Portfolio Selection with Jumps under Regime Switching

    Lin Zhao

    2010-01-01

    Full Text Available We investigate a continuous-time version of the mean-variance portfolio selection model with jumps under regime switching. The portfolio selection is proposed and analyzed for a market consisting of one bank account and multiple stocks. The random regime switching is assumed to be independent of the underlying Brownian motion and jump processes. A Markov chain modulated diffusion formulation is employed to model the problem.

  14. Molecular motors in conservative and dissipative regimes

    Perez-Carrasco, R.; Sancho, J. M.

    2011-10-01

    We present a theoretical study of a rotatory molecular motor under a conservative torque regime. We show that conservative and dissipative regimes present a different observable phenomenology. Our approach starts with a preliminary deterministic calculation of the motor cycle, which is complemented with stochastic simulations of a Langevin equation under a flashing ratchet potential. Finally, by using parameter values obtained from independent experimental information, our theoretical predictions are compared with experimental data of the F1-ATPase motor of the Bacillus PS3.

  15. Patent regimes and the commodification of knowledge

    Coriat, Benjamin; Weinstein, Olivier

    2011-01-01

    This paper analyses the evolution of the intellectual property regime (IPR), and more precisely the patent regime, in the USA since the 19th century. To do so, we consider intellectual property laws within the context of wider changes in capitalism, focusing on two main historical phases: firstly, the period covering the formation and development of 'corporate capitalism' dominated by large corporations and then the new phase, which opened up in the 1980s, marked by the rise to power of finan...

  16. Regime shifts and inflation uncertainty in Peru

    Paúl Castillo; Alberto Humala; Vicente Tuesta

    2012-01-01

    The link between inflation and inflation uncertainty is evaluated using Peruvian data, in a context of changing monetary policies because of regime shifts. A Markov regime-switching heteroskedasticity model that includes unobserved components is used. The model shows how periods of high (low) inflation accompany periods of high (low) short- and long-run uncertainty in inflation. The results of the model also illustrate how, during the recent period of price stability in Peru, both permanent a...

  17. Improving the taxation regime for electric power

    In Norway, the present taxation regime for electric power is very complex. The power companies are currently charged with ordinary tax on profits, tax on economic rent, tax on natural resources and land tax. In addition there are the rules about licence fees, yield of power due to concession conditions, and reversion. The Norwegian Electricity Industry Association (EBL), assisted by a firm of lawyers, has proposed an improvement over the current taxation regime

  18. Developmental Regimes in Africa synthesis report

    Booth, D.; Dietz, A.J.; Golooba-Mutebi, F.; Fuady, A.H.; Henley, D; Kelsall, T.; Leliveld, A.H.M.; Donge, van, J.K.

    2015-01-01

    Many African countries have experienced sustained economic growth, but few have achieved the type of structural change, driven by rising productivity, that has transformed mass living standards in parts of Asia. In the Developmental Regimes in Africa Synthesis Report, editor David Booth examines how DRA research has shed new light on how developmental regimes might emerge and be sustained in Africa in the 21st century. He outlines a concept with defining features at three levels: policy conte...

  19. Forest damage and snow avalanche flow regime

    T. Feistl; Bebi, P.; M. Christen; Margreth, S.; Diefenbach, L.; P. Bartelt

    2015-01-01

    Snow avalanches break, uproot and overturn trees causing damage to forests. The extent of forest damage provides useful information on avalanche frequency and intensity. However, impact forces depend on avalanche flow regime. In this paper, we define avalanche loading cases representing four different avalanche flow regimes: powder, intermittent, dry and wet. Using a numerical model that simulates both powder and wet snow avalanches, we study documented events with forest ...

  20. Contribution to the study of 233U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/233U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  1. Regime Diagrams for K-Theory Dispersion

    Smith, Ronald B.

    2011-06-01

    In atmospheric dispersion, the "non-Gaussian" effects of gravitational settling, the vertical gradient in diffusivity and the surface deposition do not enter uniformly but rather break up parameter space into several discrete regimes. Here, we describe regime diagrams that are constructed for K-theory dispersion of effluent from a surface line source in unsheared inhomogeneous turbulence, using a previously derived Fourier-Hankel method. This K-theory formulation differs from the traditional one by keeping a non-zero diffusivity at the ground. This change allows for turbulent exchange between the canopy and the atmosphere and allows new natural length scales to emerge. The axes on the regime diagrams are non-dimensional distance defined as the ratio of downwind distance to the characteristic length scale for each effect. For each value of the ratio of settling speed to the K gradient, two to four regimes are found. Concentration formulae are given for each regime. The regime diagrams allow real dispersion problems to be categorized and the validity of end-state concentration formulae to be judged.

  2. Fiscal Policy and Welfare under Different Exchange Rate Regimes

    Østrup, Finn

    regime in whichthe monetary authority optimises preferences which include an employment targetand an inflation target. As government spending affects the representativeindividual's utility, the choice of exchange rate regime has an impact on welfare.Keywords: exchange rate regimes; fiscal policy...

  3. Angular distribution and inertia parameters i Alpha-induced fission of 232Th, 233U, and 238U

    Rahimi Farhad M.

    2003-01-01

    Full Text Available The analysis of the selected fission fragment angular distribution from alpha induced fission is made by using an exact theoretical expression. Theoretical anisotropics obtained with transition state modes are compared with their corresponding experimental values. The agreement between the calculated and experimental values is very good. The values of the statistical parameter K02 are used for calculation of the inertia parameters. The results indicate an increase in the moment of inertia.

  4. Co-processing, catalytic reduction and remote controlled oxalate precipitation - a new route for 233U/Th MOX

    Reprocessing and recycling of fissile and fertile nuclides together without their individual separation is considered to be one of the few proliferation resistant approaches for closing the nuclear fuel cycle. The present paper explores the possibility of reducing the uranium to U4+ catalytically using H2 gas, co-precipitating both Th and U as oxalate and final conversion to oxide

  5. Laser-Nucleus Interactions: The Quasiadiabatic Regime

    Pálffy, Adriana; Hoefer, Axel; Weidenmüller, Hans A

    2015-01-01

    The interaction between nuclei and a strong zeptosecond laser pulse with coherent MeV photons is investigated theoretically. We provide a first semi-quantitative study of the quasiadiabatic regime where the photon absorption rate is comparable to the nuclear equilibration rate. In that regime, multiple photon absorption leads to the formation of a compound nucleus in the so-far unexplored regime of excitation energies several hundred MeV above the yrast line. The temporal dynamics of the process is investigated by means of a set of master equations that account for dipole absorption, stimulated dipole emission, neutron decay and induced fission in a chain of nuclei. That set is solved numerically by means of state-of-the-art matrix exponential methods also used in nuclear fuel burnup and radioactivity transport calculations. Our quantitative estimates predict the excitation path and range of nuclei reached by neutron decay and provide relevant information for the layout of future experiments.

  6. Fermi's golden rule beyond the Zeno regime

    Debierre, Vincent; Goessens, Isabelle; Brainis, Edouard; Durt, Thomas

    2015-08-01

    We reconsider the problem of the spontaneous emission of light by an excited atomic state. We scrutinize the survival probability of this excited state for very short times, in the so-called Zeno regime, for which we show that the dynamics is dictated by a coherent, in-phase, response of the on-shell and off-shell vacuum modes. We also develop a perturbative approach in order to interpolate between different temporal regimes: the Zeno, golden rule (linear), and Wigner-Weisskopf (exponential) regimes. We compare results obtained with the E ̂.x ̂ and A ̂.p ̂ interaction Hamiltonians, using successively the dipole approximation and the exact coupling.

  7. Stochastic dynamical models for ecological regime shifts

    Møller, Jan Kloppenborg; Carstensen, Jacob; Madsen, Henrik; Andersen, Tom

    Ecosystems are influenced by a variety of known and unknown drivers. Unknown drivers should be modeled as noise and it is therefore important to analyze how noise influences the deterministic skeleton of system equations. The deterministic skeleton of stochastic dynamical models contains the...... physical and biological knowledge of the system, and nonlinearities introduced here can generate regime shifts or enhance the probability of regime shifts in the case of stochastic models, typically characterized by a threshold value for the known driver. A simple model for light competition between...... phytoplankton and benthic vegetation with feedback mechanisms is formulated, and it is demonstrated that bistability can occur for specific parameter settings. When stochastic input and stochastic propagation of the states are applied on the system regime shifts occur more frequently, and the threshold...

  8. Determination of the Hall Thruster Operating Regimes

    L. Dorf; V. Semenov; Y. Raitses; N.J. Fisch

    2002-04-09

    A quasi one-dimensional (1-D) steady-state model of the Hall thruster is presented. For the same discharge voltage two operating regimes are possible -- with and without the anode sheath. For given mass flow rate, magnetic field profile and discharge voltage a unique solution can be constructed, assuming that the thruster operates in one of the regimes. However, we show that for a given temperature profile the applied discharge voltage uniquely determines the operating regime: for discharge voltages greater than a certain value, the sheath disappears. That result is obtained over a wide range of incoming neutral velocities, channel lengths and widths, and cathode plane locations. It is also shown that a good correlation between the quasi 1-D model and experimental results can be achieved by selecting an appropriate electron mobility and temperature profile.

  9. Progress towards a global nuclear liability regime

    During its April 2014 meeting, the Steering Committee for Nuclear Energy held a policy debate on 'Progress towards a Global Nuclear Liability Regime'. The Steering Committee heard presentations from several experts on nuclear liability issues. To prepare the delegates to the Steering Committee for the policy debate, the NEA Secretariat prepared a background note on the status of the nuclear liability regimes, as well as on current issues and challenges in implementing the regimes. This article is based on the background note and is intended to provide basic information on the relevant international conventions and an overview of recent developments to enhance the understanding of the legal framework in which policy-makers and practitioners are engaging to respond to the call for broader adherence to the international liability instruments. (authors)

  10. Causas estruturais e consequências dos regimes internacionais: regimes como variáveis intervenientes

    Stephen D. Krasner

    2012-06-01

    Full Text Available Os regimes internacionais são definidos como princípios, normas, regras e procedimentos de tomada de decisões ao redor dos quais as expectativas dos atores convergem em uma dada área-tema. Como ponto de partida, os regimes são conceituados como variáveis intervenientes, estando entre fatores causais básicos e os resultados e comportamentos relacionados. Há três visões a respeito da importância dos regimes: as orientações estruturais convencionais desvalorizam os regimes como sendo, na melhor das hipóteses, ineficazes; as orientações grocianas vêem os regimes como componentes íntimos do sistema internacional; as perspectivas estruturalistas modificadas vêem os regimes como significativos somente em certas condições restritas. Para os argumentos grociano e estruturalista modificado - que concordam com a visão de que os regimes podem influenciar resultados e comportamentos - , o desenvolvimento de regimes é visto como uma função de cinco variáveis causais básicas: auto-interesse egoísta; poder político; normas e princípios difusos; usos e costumes; conhecimento.

  11. Supercurrent in the quantum Hall regime.

    Amet, F; Ke, C T; Borzenets, I V; Wang, J; Watanabe, K; Taniguchi, T; Deacon, R S; Yamamoto, M; Bomze, Y; Tarucha, S; Finkelstein, G

    2016-05-20

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing. PMID:27199424

  12. Supercurrent in the quantum Hall regime

    Amet, F.; Ke, C. T.; Borzenets, I. V.; Wang, J.; Watanabe, K.; Taniguchi, T.; Deacon, R. S.; Yamamoto, M.; Bomze, Y.; Tarucha, S.; Finkelstein, G.

    2016-05-01

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing.

  13. The oil tax regime of Azerbaijan

    Anderson, Gerard

    1998-07-01

    Azerbaijan has a long history in the oil business and a chance of a spectacular future. To understand why the oil tax regime evolved into its present form and how it is likely to develop, it is necessary to know something of the country's history and the commercial environment. Consequently the presentation begins by discussing these items. It then outlines the Production Sharing Agreement regime in Azerbaijan and then deals with the Kazakh and Georgian Tax Codes, as these are likely to be the basis of a new general tax law in Azerbaijan from 1999. The presentation includes comments on the New Draft Tax Code of 1998.

  14. WELFARE REGIMES IN LATIN AMERICA AND CARIBBEAN

    Melisa Campana-Alabarce

    2015-06-01

    Full Text Available This article provides a characterization of Latin American and Caribbean Welfare regimes in historiographical perspective. Firstly, it makes a review of the emergence conditions of Welfare States in Western Europe and its core features, with particular emphasis on its role as a method to regulate inequalities in industrial capitalism. Dialoguing with it, then stops in the specific configurations that welfare regimes have taken in Latin America during the course of the twentieth century. Finally, it provides a map of its contemporary features and the major challenges that the States of the region face in his capacity as right guarantors for the future.

  15. High temperature regime of corium concrete interactions

    The high temperature regime of corium concrete interaction is examined from the point of view of its sensitivity to the completeness of reaction of the gaseous concrete decomposition products with the metallic components of the melt. A program based on the DECOMP modeling approach has been utilized for this purpose. For a corium/concrete heat transfer that is consistent with the erosion rates observed in the BETA experiments the primary effect of the extent of reaction completeness is on the duration of the high temperature regime. This implies a potentially important effect on the aerosols stripped out during this portion of the interaction

  16. Primary Qualification of Matrimonial Regime Notion

    Nadia Cerasela ANITEI

    2012-01-01

    By adopting Law no. 287 of July 17, 2009 on the Civil Code republished by Law no. 71/2011 the new Civil Code is subject to the modern legislations tendencies to create a triple balance in terms of property relations between spouses by means of the matrimonial property regimes established:1. between spouses: through the appearance of matrimonial agreements, which have led to the adoption of more flexible legal rules which allow spouses a certain freedom to choose the regime of patrimonial rela...

  17. Light focusing in the Anderson Regime

    Leonetti, Marco; Mafi, Arash; Conti, Claudio

    2014-01-01

    Anderson localization is a regime in which diffusion is inhibited and waves (also electromagnetic waves) get localized. Here we exploit adaptive optics to achieve focusing in disordered optical fibers in the Anderson regime. By wavefront shaping and optimization, we observe the generation of a propagation invariant beam, where light is trapped transversally by disorder, and show that Anderson localizations can be also excited by extended speckled beams. We demonstrate that disordered fibers allow a more efficient focusing action with respect to standard fibers in a way independent of their length, because of the propagation invariant features and cooperative action of transverse localizations.

  18. Quaternary Faults and Stress Regime of Venezuela

    F.A. Audemard M.; A. Singer P.; J-P. Soulas

    2006-01-01

    Spatial configuration of Quaternary active tectonic features along the southern Caribbean plate boundary suggests that the region is subject to a compressive strike-slip (transpressional senso lato) regime, characterized by a NNW-SSE maximum horizontal stress (sH=s1) and/or an ENE-WSW minimum (s h=s3 or s2) horizontal stress. Stress inversion applied to fault-plane kinematic indicators measured essentially in Plio-Quaternary sedimentary rocks confirms this tectonic regime. Accordingly, this s...

  19. Economic performance and North Korean regime legitimacy

    Moore, Patrick J.

    2014-01-01

    This thesis examines the sources of legitimacy for the North Korean regime in an effort to explain what role, if any, economic performance has played in keeping the Kim family in power. This thesis provides a historical look at the development of the North Korean regime from the beginning under Kim Il-sung to the current generation of rule under Kim Jong-un. The core argument of the thesis is broken into two major time periods, with the economic downturn of the early 1990s serving as the divi...

  20. A Comparative Typology of Pension Regimes

    Arjan Soede; Cok Vrooman

    2008-01-01

    This report presents an empirical typology of pension regimes in the European Union, the US, Canada, Australia and Norway. The categorisation is based on 34 quantitative and qualitative characteristics of the mandatory parts of the pension systems in these countries. The empirical analysis shows tha

  1. REGIME ALIMENTAR DE GIRINOS DE RÃ TOURO

    José Teixeira de Seixas Filho

    2013-03-01

    Full Text Available We used 525 bullfrog tadpoles, distributed into 15 boxes with one tadpole per liter. The water was daily renewal (200%. The feeding regimes were constituted of five arrangements using seven commercial rations with levels of 22, 28, 32, 36, 40, 45 and 55% of crude protein (CP, supplied every 15 days. We used a random blocks design, subdivided plots with three replications. The subplots were constituted of five biometries: at the beginning of the experiment, at 15, 30, 45, and 60 days. The tadpoles submitted to feeding regime FR1, with 22, 32, 36, and 40% of CP, presented the highest consumption and the same performance as the others. Tadpoles that received FR5, with 40, 45, 45 and 50% of CP, presented greater weight, however, they showed smaller weight gain, greater consumption, conversion and mortality, indicating that this regime is expensive and not adequate for management. Feeding regimes FR2, with 28, 32, 36 and 40% of CP, and FR3, with 32, 36, 40 and 45% of CP, were more adjusted to this kind of management. Animals in all treatments showed higher performance that animals fed traditionally.

  2. Estimation in autoregressive models with Markov regime

    Ríos, Ricardo; Rodríguez, Luis

    2005-01-01

    In this paper we derive the consistency of the penalized likelihood method for the number state of the hidden Markov chain in autoregressive models with Markov regimen. Using a SAEM type algorithm to estimate the models parameters. We test the null hypothesis of hidden Markov Model against an autoregressive process with Markov regime.

  3. Optimal dividend distribution under Markov regime switching

    Z. Jiang; M. Pistorius

    2012-01-01

    We investigate the problem of optimal dividend distribution for a company in the presence of regime shifts. We consider a company whose cumulative net revenues evolve as a Brownian motion with positive drift that is modulated by a finite state Markov chain, and model the discount rate as a determini

  4. European welfare regimes: Political orientations versus poverty

    Josifidis Kosta

    2011-01-01

    Full Text Available This inquiry analyzes how political orientations shape welfare states and labour market institutions when seeking to reduce poverty. In order to identify effects of these two key variables, we conduct a panel regression analysis that includes two poverty measures: poverty rates before and after social spending. This inquiry considers 14 EU countries, and in the period from 1995 to 2008, which are grouped according to welfare state regimes. We consider Social Democratic, Corporatist, Mediterranean and Liberal welfare state regimes. Panel regression results indicate that political orientation engenders no significant statistically measurable effects on poverty rates before social spending. Effects register, however, as significant when considering poverty rates after social spending. With respect to the first set of results, we advance two key explanations. First, we note a longer period of time is necessary in order to observe actual effects of political orientation on market generated poverty. Second, political parties with their respective programs do not register as influential enough to solve social problems related to income distribution when taken alone. Influences register as indirect and are expressed through changes in employment rates and social spending. The second set of results support the hypothesis that a selected political regime does indeed contribute to poverty reduction. In sum, political orientation and political regime does indeed affect poverty through welfare state institutions, as well as through labour market institutions.

  5. Early detection of ecosystem regime shifts

    Lindegren, Martin; Dakos, Vasilis; Groeger, Joachim P.; Gardmark, Anna; Kornilovs, Georgs; Otto, Saskia A.; Moellmann, Christian

    2012-01-01

    methods may have limited utility in ecosystem-based management as they show no or weak potential for early-warning. We therefore propose a multiple method approach for early detection of ecosystem regime shifts in monitoring data that may be useful in informing timely management actions in the face of...

  6. Quality Regimes in Agro-Food Industries

    Staricco, Juan Ignacio; Ponte, Stefano

    2015-01-01

    In this article, we examine the transformative potential of changing quality regimes in agro-food industries through the analysis of whether Fair Trade wine in Argentina provides a meaningful economic alternative that goes beyond the impact it has on direct beneficiaries. The wine sector has a long...

  7. Radiative effects of global MODIS cloud regimes

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji

    2016-03-01

    We update previously published Moderate Resolution Imaging Spectroradiometer (MODIS) global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 data set. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux data sets. Our results clearly show that the CRs are radiatively distinct in terms of shortwave, longwave, and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles, to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance data sets suffering from imperfect spatiotemporal matching depend on CR and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations.

  8. An emissions trading regime for Canada

    In 1998, over twelve papers were published on emissions trading regimes in Canada by the National Round Table on the Environment and the Economy (NRTEE), a federal government agency whose members represent stakeholders as varied as business, environmental groups, academics, aboriginal groups and others. One of the recommendations that emerged was for the computer modelling of the possibilities that had been identified for a domestic trading regime in Canada for greenhouse gases. It is unclear whether the modelling was ever performed as the file was taken over by the Finance Department under the umbrella of a special emission trading table that examined Canada's commitment under the Kyoto Protocol. The author examined questions pertaining to whether a domestic trading regime is essential, and what its characteristics should be in case it was deemed essential or advisable to have one. The upstream versus downstream application was looked at, as well as grand-fathering versus auction. Provincial issues were then addressed, followed by meshing with a credit system. International systems were reviewed. Early action was discussed, whereby an emitter seeks credit for action taken toward reductions since the original reference year of 1990. The case of emitters having bought or sold permits since the original reference years will also want those trades recognized under a trading regime. The author indicated that it seems probable that an emission trading system will eventually be implemented and that a debate on the issue should be initiated early

  9. The global safety regime - Setting the stage

    Full text: The existing global safety regime has arisen from the exercise of sovereign authority, with an overlay of voluntary international cooperation from a network of international and regional organizations and intergovernmental agreements. This system has, in the main, served us well. For several reasons, the time is ripe to consider the desired shape of a future global safety regime and to take steps to achieve it. First, every nation's reliance on nuclear power is hostage to some extent to safety performance elsewhere in the world because of the effects on public attitudes and hence there is an interest in ensuring achievement of common standards. Second, the world is increasingly interdependent and the vendors of nuclear power plants seek to market their products throughout the globe. Efficiency would arise from the avoidance of needless differences in approach that require custom modifications from country to country. Finally, we have much to learn from each other and a common effort would strengthen us all. Such an effort might also serve to enhance public confidence. Some possible characteristics of such a regime can be identified. The regime should reflect a global consensus on the level of safety that should be achieved. There should be sufficient standardization of approach so that expertise and equipment can be used everywhere without significant modification. There should be efforts to ensure a fundamental commitment to safety and the encouragement of a safety culture. And there should be efforts to adopt more widely the best regulatory practices, recognizing that some modifications in approach may be necessary to reflect each nation's legal and social culture. At the same type, the regime should have the characteristics of flexibility, transparency, stability, practicality, and encouragement of competence. (author)

  10. The global safety regime - Setting the stage

    The existing global safety regime has arisen from the exercise of sovereign authority, with an overlay of voluntary international cooperation from a network of international and regional organizations and intergovernmental agreements. This system has, in the main, served us well. For several reasons, the time is ripe to consider the desired shape of a future global safety regime and to take steps to achieve it. First, every nation's reliance on nuclear power is hostage to some extent to safety performance elsewhere in the world because of the effects on public attitudes and hence there is an interest in ensuring achievement of common standards. Second, the world is increasingly interdependent and the vendors of nuclear power plants seek to market their products throughout the globe. Efficiency would arise from the avoidance of needless differences in approach that require custom modifications from country to country. Finally, we have much to learn from each other and a common effort would strengthen us all. Such an effort might also serve to enhance public confidence. Some possible characteristics of such a regime can be identified. The regime should reflect a global consensus on the level of safety that should be achieved. There should be sufficient standardization of approach so that expertise and equipment can be used everywhere without significant modification. There should be efforts to ensure a fundamental commitment to safety and the encouragement of a safety culture. And there should be efforts to adopt more widely the best regulatory practices, recognizing that some modifications in approach may be necessary to reflect each nation's legal and social culture. At the same type, the regime should have the characteristics of flexibility, transparency, stability, practicality, and encouragement of competence. (author)

  11. De facto and official exchange rate regimes in transition economies

    von Hagen, Jürgen; Zhou, Jizhong

    2002-01-01

    This paper provides an empirical investigation on the discrepancies between official exchange rate regimes and de facto exchange rate policies in transition economies. Since official and de facto regime choices are not independent of each other, we adopt a bivariate probit model to describe the joint determination of the two regime choices. After finding the important determinants of both regime choices, we use a univariate probit model to describe the determination of regime discrepancies. W...

  12. The Effect of Market Regimes on Style Allocation

    Ammann, Manuel; Verhofen, Michael

    2006-01-01

    We analyse time-varying risk premia and the implications for portfolio choice. Using Markov Chain Monte Carlo (MCMC) methods, we estimate a multivariate regime-switching model for the Carhart (1997) four factor model. We find two clearly separable Regimes with different mean returns, volatilities and correlations. In the High-Variance Regime, only value stocks deliver a good performance, whereas in the Low-Variance Regime, the market portfolio and momentum stocks promise high returns. Regime-...

  13. Regime shifts in the anthropocene: drivers, risks, and resilience.

    Rocha, Juan Carlos; Peterson, Garry D; Biggs, Reinette

    2015-01-01

    Many ecosystems can experience regime shifts: surprising, large and persistent changes in the function and structure of ecosystems. Assessing whether continued global change will lead to further regime shifts, or has the potential to trigger cascading regime shifts has been a central question in global change policy. Addressing this issue has, however, been hampered by the focus of regime shift research on specific cases and types of regime shifts. To systematically assess the global risk of regime shifts we conducted a comparative analysis of 25 generic types of regime shifts across marine, terrestrial and polar systems; identifying their drivers, and impacts on ecosystem services. Our results show that the drivers of regime shifts are diverse and co-occur strongly, which suggests that continued global change can be expected to synchronously increase the risk of multiple regime shifts. Furthermore, many regime shift drivers are related to climate change and food production, whose links to the continued expansion of human activities makes them difficult to limit. Because many regime shifts can amplify the drivers of other regime shifts, continued global change can also be expected to increase the risk of cascading regime shifts. Nevertheless, the variety of scales at which regime shift drivers operate provides opportunities for reducing the risk of many types of regime shifts by addressing local or regional drivers, even in the absence of rapid reduction of global drivers. PMID:26267896

  14. Online recognition of the multiphase flow regime

    2008-01-01

    The key reasons that the present method cannot be used to solve the industrial multi- phase flow pattern recognition are clarified firstly. The prerequisite to realize the online recognition is proposed and recognition rules for partial flow pattern are obtained based on the massive experimental data. The standard templates for every flow regime feature are calculated with self-organization cluster algorithm. The multi-sensor data fusion method is proposed to realize the online recognition of multiphase flow regime with the pressure and differential pressure signals, which overcomes the severe influence of fluid flow velocity and the oil fraction on the recognition. The online recognition method is tested in the practice, which has less than 10 percent measurement error. The method takes advantages of high confidence, good fault tolerance and less requirement of single sensor performance.

  15. Online recognition of the multiphase flow regime

    BAI BoFeng; ZHANG ShaoJun; ZHAO Liang; ZHANG XiMin; GUO LieJin

    2008-01-01

    The key reasons that the present method cannot be used to solve the industrial multi-phase flow pattern recognition are clarified firstly. The prerequisite to realize the online recognition is proposed and recognition rules for partial flow pattern are obtained based on the massive experimental data. The standard templates for every flow regime feature are calculated with self-organization cluster algorithm. The multi-sensor data fusion method is proposed to realize the online recognition of multiphase flow regime with the pressure and differential pressure signals, which overcomes the severe influence of fluid flow velocity and the oil fraction on the recognition. The online recognition method is tested in the practice, which has less than 10 percent measurement error. The method takes advantages of high confidence, good fault tolerance and less requirement of single sensor performance.

  16. Recent Activities on Global Nuclear Safety Regime

    Recently, rapid progress on the globalization of the nuclear safety issues is being made in IAEA (International Atomic Energy Agency) and its member states. With the globalization, the need for international cooperation among international bodies and member states continues to grow for resolving these universal nuclear safety issues. Furthermore, the importance of strengthening the global nuclear safety regime is emphasized through various means, such as efforts in application of IAEA safety standards to all nuclear installations in the world and in strengthening the code of conduct and the convention on nuclear safety. In this regards, it is important for us to keep up with the activities related with the global nuclear safety regime as an IAEA member state and a leading country in nuclear safety regulation

  17. Progress towards a global nuclear liability regime

    As the Fukushima-Daiichi nuclear power plant accident brought a renewed focus to the discussion of international nuclear liability regimes, and notably the administration of a liability system to compensate damages resulting from a nuclear accident, this article recalls the background on existing international nuclear liability conventions (original and revised Paris and Vienna conventions), briefly indicates the common principles reflected in the international nuclear liability conventions. The author outlines the challenges in achieving a global nuclear liability regime, reports and comments the Japanese experience in handling compensation issues in the wake of the Fukushima accident. He gives an overview of recent developments: IAEA action plan on nuclear safety, action of the International Expert Group on Nuclear Liability (INLEX), CSC or Convention on Supplementary Compensation

  18. Regimes de espaço

    Eric Landowski

    2015-06-01

    Full Text Available Space Regimes - Based on a general model of interaction, the present analysis attempts to account for the diversity of the ways space may be apprehended in lived experience. It leads to the definition of four configurations that correspond to as many regimes of relation with the environing world. The conventional space of the circulation of values takes the archetypical shape of the net (incarnated today by Internet. The operational space is that of our dealing with objects within a material environment seen as a tissue of stable and intelligible relations. The experienced space of bodies’ movement, to which one may give as an emblem the spiral, expresses the dynamics of sensitive relationships between the self and the other. The existential space is that of our presence in a universe without boundaries, which no one can properly represent oneself but that nonetheless haunts art and thought: its figure is the abyss.

  19. Dominant takeover regimes for genetic algorithms

    Noever, David; Baskaran, Subbiah

    1995-01-01

    The genetic algorithm (GA) is a machine-based optimization routine which connects evolutionary learning to natural genetic laws. The present work addresses the problem of obtaining the dominant takeover regimes in the GA dynamics. Estimated GA run times are computed for slow and fast convergence in the limits of high and low fitness ratios. Using Euler's device for obtaining partial sums in closed forms, the result relaxes the previously held requirements for long time limits. Analytical solution reveal that appropriately accelerated regimes can mark the ascendancy of the most fit solution. In virtually all cases, the weak (logarithmic) dependence of convergence time on problem size demonstrates the potential for the GA to solve large N-P complete problems.

  20. Deuteron structure in the deep inelastic regime

    Canal, C A Garcìa; Vento, V

    2016-01-01

    We study nuclear effects on the deuteron in the deep inelastic regime using the newest available data analyzing their $Q^2$ dependence. We conclude that precise EMC ratios for large $Q^2$ (> 30, GeV$^2$) cannot be obtained without considering these nuclear effects. For this purpose we use a scheme which parametrizes these effects in a simple manner and compare our results with other recent proposals.

  1. Financial Fragility and the Exchange Rate Regime

    Chang, Roberto; Velasco, Andres

    1998-01-01

    We study financial fragility, exchange rate crises and monetary policy in an open economy model in which banks are maturity transformers as in Diamond-Dybvig. The banking system, the exchange rate regime, and central bank credit policy are seen as parts of a mechanism intended to maximize social welfare; if the mechanism fails, banking crises and speculative attacks become possible. We compare currency boards, fixed rate and flexible rates, with and without a lender of last resort. A currency...

  2. Tax compliance under tax regime changes

    Heinemann, Friedrich; Kocher, Martin G.

    2010-01-01

    In this paper we focus on the compliance effects of tax regime changes. According to the economic model of tax evasion, a tax reform should affect compliance through its impact on tax rates and incentives. Our findings demonstrate the importance of at least two further effects not covered by the traditional model: First, reform losers tend to evade more taxes after the reform. Second, a reform from a proportionate to a progressive system decreases compliance compared to a switch in the revers...

  3. Law and Courts in Authoritarian Regimes

    Moustafa, Tamir

    2014-01-01

    "Once regarded as mere pawns of their regimes, courts in authoraitarian states are now the subject of considerable attention within the field of comparative judicial politics.  New research examines the ways in which law and courts are deployed as instruments of governance, how they structure state-society contention, and the circumstances in which courts are transformed into sites of active resistance.  This new body of research constitutes an emergent field of inquiry, while simul...

  4. Exchange Rate Regimes and International Business Cycles

    Theptida Sopraseuth

    2003-01-01

    This paper investigates the impact of exchange rate regimes on international business cycles and focuses on the consequences of membership to the European Monetary System. The volatility puzzle uncovered by Baxter and Stockman [1989, Journal of Monetary Economics 23, 377–401] after assessing the consequences of the Bretton Woods system turns out to be a robust stylized fact: real and nominal exchange rates display a higher volatility under floating rates while the variability of macroeconom...

  5. Snowpack regimes of the Western United States

    Trujillo, Ernesto; Molotch, Noah P.

    2014-01-01

    Snow accumulation and melt patterns play a significant role in the water, energy, carbon, and nutrient cycles in the montane environments of the Western United States. Recent studies have illustrated that changes in the snow/rainfall apportionments and snow accumulation and melt patterns may occur as a consequence of changes in climate in the region. In order to understand how these changes may affect the snow regimes of the region, the current characteristics of the snow accumulation and mel...

  6. Financing welfare regimes: mapping heterogeneous revenue structures

    Gough, Ian; Abu-Sharkh, Miriam

    2011-01-01

    This article studies how the composition of public revenues in terms of sources (such as taxation, social insurance contributions, mineral rents, foreign aid) is associated with different welfare regimes and social policy outcomes. It is divided into two halves: a review of literature and research, and a cross-national data analysis. The first half reviews literature on the emergence of tax and revenue systems in the West, and on the relevance of these frameworks and findings to developing co...

  7. The Forex Regime and EMU Expansion

    Foreest, P.W.; de Vries, Casper

    2002-01-01

    This paper provides evidence that the choice of the foreign exchange regime is not of first order importance for achieving high output growth. It is argued that due to the forward looking nature of the foreign exchange market, exchange rate stability hinges on the current and anticipated coherency of monetary and fiscal policies. We demonstrate this empirically on a panel including potential EMU accession countries. By means of rank regression analysis we uncover the partial links across the ...

  8. Dynamic Regime of Ignition of Solid Propellant

    Zolotorev Nikolay

    2016-01-01

    Full Text Available This article presents a dynamic regime of exposure of the radiant flux on the sample of gun-cotton. Obtained time the ignition of gun-cotton in the heating conditions of increasing heat flux in the range from 0.2 W/cm2 to 22 W/cm2. A comparison of the delay times of the ignition when heated variable and constant heat flux.

  9. Exchange Rate Regimes, Location, and Specialization

    Luca Antonio Ricci

    2006-01-01

    This paper investigates the effects of fixed versus flexible exchange rates on firms' location choices and on countries' specialization patterns. In a two-country, twodifferentiated-goods monetary model, uncertainty arises after wages are set and prices are optimally chosen. The paper shows that countries are more specialized under flexible than fixed rates, which indicates that the pattern of specialization is not uniquely defined by trade models but also depends on the exchange rate regime....

  10. Corruption in Privatization and Governance Regimes

    Maria Cristina Molinari

    2011-01-01

    We consider the choice to privatize the provision of a public good in a hierarchical model with three layers: a Central Government, a decentralized agency and a (private or public) manager. In a good governance regime the privatization can be devolved upon the decentralized agency while it cannot when the governance is bad. There are two types of information asymmetries: managers are privately informed of their efficiency in reducing costs (and quality) and only the decentralized agency knows...

  11. Marginal Mean Models for Dynamic Regimes

    Murphy, S A; Laan, M.J. van der; Robins, J.M.

    2001-01-01

    A dynamic treatment regime is a list of rules for how the level of treatment will be tailored through time to an individual’s changing severity. In general, individuals who receive the highest level of treatment are the individuals with the greatest severity and need for treatment. Thus there is planned selection of the treatment dose. In addition to the planned selection mandated by the treatment rules, the use of staff judgment results in unplanned selection of the treatment level. Given ob...

  12. Tax incentive regimes: models and research methods

    Sokolovska, Olena; Sokolovskyi, Dmytro

    2014-01-01

    Paper deals with problem of effectiveness of tax incentive regimes. Support of priority industries remains currently important for transition economies. At once, such countries more often than developed ones face the imperfection of tax incentive mechanisms. Notably, such problems are common to Ukrainian and Moldavian economies, where the legislative support or its implementation in the area of preferential taxation of innovative enterprises which contribute essentially to sustainable develop...

  13. Taxation, corruption and the exchange rate regime

    Hefeker, Carsten

    2008-01-01

    The paper analyzes the relation between institutional quality, such as corruption, in a country and its monetary regime. It is shown that a credibly fixed exchange rate to a low inflation country, like a currency board, can reduce corruption and improve the fiscal system. A monetary union, however, has ambiguous effects. I find that that there is convergence between countries with regard to the level of corruption.

  14. Monetary policy regimes and the Nordic model

    Schewe, Theo

    2015-01-01

    In many contexts, the Nordic countries are regarded as a natural bloc of nations that have common political, cultural and economic characteristics. Open to globalisation, the small Nordic countries are exposed to strong global competition and cyclical influences. Therefore, the basis of the model may be to combine collective risk sharing and openness to globalisation. Studies of the Nordic model do not focus on the question whether the monetary policy regime is a constitutive element of the m...

  15. Energy regime choices: nuclear or not?

    Elliott, David

    2006-01-01

    The energy system in industrialized countries is changing in what can be seen as an example of the technological regime change, reflecting a wider shift towards environmentally sustain-able technology which may impact on all sectors in the economy. In recent years, the emphasis in the UK's power generation system has increasingly been on smaller scale power plants, combined cycle gas turbine plants and wind farms of the order of 20-100 megawatts instead of giant gigawatt coal and nuclear p...

  16. Nonlinear diffusion regimes in stochastic magnetic fields

    The transport of collisional particles in stochastic magnetic fields is studied using the decorrelation trajectory method. The nonlinear effect of magnetic line trapping is considered together with particle collisions. The running diffusion coefficient is determined for arbitrary values of the statistical parameters of the stochastic magnetic field and of the collisional velocity. New diffusion regimes are found in the conditions for which the trapping of magnetic field lines is effective. (author)

  17. APPLICABLE LAW PRINCIPLES FOR MATRIMONIAL PROPERTY REGIMES

    Andreea-Lorena CODREANU

    2014-01-01

    More and more often, marriages are concluded between people of different nationalities, which brings an extraneous dimension to the legal status and matrimonial property regime jurisdiction conflict. Many European states (among which Romania, through its new Civil Code) offer the advantage of clauses that could be used by any of the spouses, with regard to the applicable law. In case of divorce, consequences differ with the applicable law. Spouses who divorce and divide their assets based on ...

  18. Supersonic free jet, molecular free regime

    The structure of the free jet emitted by a converging nozzle as obtained by the method of characteristics by Ashkenas and Sherman is described in details. In particular the dependence of the field variable by the distance from the nozzle is given. The transition from continuum to molecular free regime is then considered and the sudden freeze approximation is introduced. The processing of monoatomic and polyatomic gasses is also considered

  19. Primary Qualification of Matrimonial Regime Notion

    Nadia Cerasela ANITEI

    2012-12-01

    Full Text Available By adopting Law no. 287 of July 17, 2009 on the Civil Code republished by Law no. 71/2011 the new Civil Code is subject to the modern legislations tendencies to create a triple balance in terms of property relations between spouses by means of the matrimonial property regimes established:1. between spouses: through the appearance of matrimonial agreements, which have led to the adoption of more flexible legal rules which allow spouses a certain freedom to choose the regime of patrimonial relations between them;2. within the family: to protect the interests of the family, they resorted to mandatory rules providing for limitations and prohibitions (art.321-322 on the family home – a new notion in the Romanian law, art.316 on the acts of disposal seriously threatening family interests;3. between family and society-third parties: by establishing formal requirements of legal acts, including matrimonial agreements to be concluded by notarial act that must be given to publicity afterwards.Also, considering the fact that Romania is a member state of the European Union and that more and more Romanian people are living abroad or marry foreigners, we consider the harmonization of legislation in order to determine the law applicable to such relationships as a highly important requirement.Given these issues we will devote the present study: to primary qualification of the matrimonial regime notion.

  20. Constructing an interdisciplinary flow regime recommendation

    Bartholow, J.M.

    2010-01-01

    It is generally agreed that river rehabilitation most often relies on restoring a more natural flow regime, but credibly defining the desired regime can be problematic. I combined four distinct methods to develop and refine month-by-month and event-based flow recommendations to protect and partially restore the ecological integrity of the Cache la Poudre River through Fort Collins, Colorado. A statistical hydrologic approach was used to summarize the river's natural flow regime and set provisional monthly flow targets at levels that were historically exceeded 75% of the time. These preliminary monthly targets were supplemented using results from three Poudre-specific disciplinary studies. A substrate maintenance flow model was used to better define the high flows needed to flush accumulated sediment from the river's channel and help sustain the riparian zone in this snowmelt-dominated river. A hydraulic/habitat model and a water temperature model were both used to better define the minimum flows necessary to maintain a thriving cool water fishery. The result is a range of recommended monthly flows and daily flow guidance illustrating the advantage of combining a wide range of available disciplinary information, supplemented by judgment based on ecological principles and a general understanding of river ecosystems, in a highly altered, working river. ?? 2010 American Water Resources Association.

  1. The kinetic regime of the Vicsek model

    Chepizhko, A. A.; Kulinskii, V. L.

    2009-12-01

    We consider the dynamics of the system of self-propelling particles modeled via the Vicsek algorithm in continuum time limit. It is shown that the alignment process for the velocities can be subdivided into two regimes: "fast" kinetic and "slow" hydrodynamic ones. In fast kinetic regime the alignment of the particle velocity to the local neighborhood takes place with characteristic relaxation time. So, that the bigger regions arise with the velocity alignment. These regions align their velocities thus giving rise to hydrodynamic regime of the dynamics. We propose the mean-field-like approach in which we take into account the correlations between density and velocity. The comparison of the theoretical predictions with the numerical simulations is given. The relation between Vicsek model in the zero velocity limit and the Kuramoto model is stated. The mean-field approach accounting for the dynamic change of the neighborhood is proposed. The nature of the discontinuity of the dependence of the order parameter in case of vectorial noise revealed in Gregorie and Chaite, Phys. Rev. Lett., 92, 025702 (2004) is discussed and the explanation of it is proposed.

  2. QCD in the δ-regime

    The δ-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the δ-expansion - applies, based on a quantum mechanical treatment of the quasi onedimensional system. In particular, for vanishing quark masses one obtains a residual pion mass MRπ, which has been computed to the third order in the δ-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the δ-regime. This is very tedious, but results compatible with the predictions for MRπ have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the δ-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-leading Low Energy Constant anti l3. (orig.)

  3. QCD in the delta-Regime

    Bietenholz, W; Gockeler, M; Horsley, R; Nakamura, Y; Pleiter, D; Rakow, P E L; Schierholz, G; Zanotti, J M

    2011-01-01

    The delta-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the delta-expansion - applies, based on a quantum mechanical treatment of the quasi one-dimensional system. In particular, for vanishing quark masses one obtains a residual pion mass M_pi^R, which has been computed to the third order in the delta-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the delta-regime. This is very tedious, but results compatible with the predictions for M_pi^R have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the delta-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-...

  4. QCD in the δ-Regime

    The (δ-regime of QCD is characterised by light quarks in a small spatial box, but a large extent in (Euclidean) time. In this setting a specific variant of chiral perturbation theory - the (δ-expansion - applies, based on a quantum mechanical treatment of the quasi one-dimensional system. In particular, for vanishing quark masses one obtains a residual pion mass MRπ, which has been computed to the third order in the δ-expansion. A comparison with numerical measurements of this residual mass allows for a new determination of some Low Energy Constants, which appear in the chiral Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in the δ-regime. This is very tedious, but results compatible with the predictions for MRπ, have been obtained. Then we show that an extrapolation of pion masses measured in a larger volume towards the (δ-regime leads to good agreement with the theoretical predictions. From those results, we also extract a value for the (controversial) sub-leading Low Energy Constant l-bar3.

  5. Interpolation between the epsilon and p regimes

    Aoki, Sinya

    2011-01-01

    We reconsider chiral perturbation theory in a finite volume and develop a new computational scheme which smoothly interpolates the conventional epsilon and p regimes. The counting rule is kept essentially the same as in the p expansion. The zero-momentum modes of Nambu-Goldstone bosons are, however, treated separately and partly integrated out to all orders as in the epsilon expansion. In this new scheme, the theory remains infra-red finite even in the chiral limit, while the chiral-logarithmic effects are kept present. We calculate the two-point function in the pseudoscalar channel and show that the correlator has a constant contribution in addition to the conventional hyperbolic cosine function of time t. This constant term rapidly disappears in the p regime but it is indispensable for a smooth convergence of the formula to the epsilon regime result. Our calculation is useful to precisely estimate the finite volume effects in lattice QCD simulations on the pion mass Mpi and kaon mass MK, as well as their de...

  6. British Columbia's new coalbed methane royalty regime

    The British Columbia Ministry of Energy and Mines is promoting the development of the coalbed methane (CBM) industry in the province in order to make CBM a viable and competitive investment option for industry. It is establishing a regulatory and fiscal regime for CBM development. Issues of concern regarding CBM development include water production, gas production rates, well numbers, and marginal economics. The features of the CBM royalty regime include a new producer cost of service allowance, the creation of a CBM royalty tax bank to collect excess PCOS allowances, and a royalty tax credit for wells drilled by the end of February, 2004. The marginal well adjustment factor threshold has been raised from 180 mcf per day to 600 mcf per day for CBM only. It was noted that royalties will probably not be payable for several years following the first commercial well because royalties are very depending on capital and operating costs, local infrastructure and price. Royalty regimes cannot save CBM from low gas prices, poor resources or economics. 2 figs

  7. JT-60U high performance regimes

    High performance regimes of JT-60U plasmas are presented with an emphasis upon the results from the use of a semi-closed pumped divertor with W-shaped geometry. Plasma performance in transient and quasi steady states has been significantly improved in reversed shear and high-β p regimes. The reversed shear regime elevated an equivalent QDTeq transiently up to 1.25(nD(0)τE Ti(0) = 8.6x1020m-3 · s · keV) in a reactor-relevant thermonuclear dominant regime. Long sustainment of enhanced confinement with internal transport barriers (ITBs) with a fully non-inductive current drive in a reversed shear discharge was successfully demonstrated with LH wave injection. Performance sustainment has been extended in the high-β p regime with a high triangularity achieving a long sustainment of plasma conditions equivalent to QDTeq ∼ 0.16(nD(0)τE Ti(0) ∼ 1.4x1020m-3 · s · keV) for ∼ 4.5 s with a large non-inductive current drive fraction of 60-70% of the plasma current. Thermal and particle transport analyses show significant reduction of thermal and particle diffusivities around ITB resulting in a strong Er shear in the ITB region. The W-shaped divertor is effective for He ash exhaust demonstrating steady exhaust capability of τHe*/τE ∼ 3 - 10 in support of ITER. Suppression of neutral back flow and chemical sputtering effect have been observed while MARFE onset density is rather decreased. Negative-ion based neutral beam injection (N-NBI) experiments have created a clear H-mode transition. Enhanced ionization cross-section due to multi-step ionization processes was confirmed as theoretically predicted. A current density profile driven by N-NBI is measured in a good agreement with theoretical prediction. N-NBI induced TAE modes characterized as persistent and bursting oscillations have been observed from a low hot beta of h > ∼ 0.1 - 0.2% without a significant loss of fast ions. (author)

  8. Refrigeration. Two-Phase Flow. Flow Regimes and Pressure Drop

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature....

  9. Laboratory Exploration of Multiple Zonal Jet Regimes

    Smith, C. A.; Speer, K. G.; Griffiths, R. W.

    2012-12-01

    The differentially heated, rotating annulus has classically been used to study wave interactions within a single, baroclinic jet. At high rotation rates, the baroclinic instability of the flow leads to a transition to a turbulent, eddy-dominated regime. In the presence of a topographic beta effect, the flow has been observed to produce multiple, meandering zonal jets that are qualitatively similar to those found in planetary atmospheres and in the Antarctic Circumpolar Current (ACC). Our study builds on previous annulus experiments [1] by making observations further within this new regime. We observe with PIV and other techniques how the structure of the flow responds to changes in various parameters such as tank geometry, gradient in the Coriolis parameter, rotation rate, and differential thermal forcing. By not employing the more typical direct forcing of small scales, but by applying a large scale forcing over the annulus gap width, this study allows the varying effects of eddy scale selection, enstrophy cascade, etc. to naturally generate flow that more closely resembles planetary atmospheres and the ACC. We seek nondimensional parameters that significantly control zonation in a real fluid. These observations will provide a metric for the comparison of various theoretical models for multiple zonal jet formation. Other properties of the jets, such as their migration, meandering, bifurcation, and merging, can also be observed in an idealized situation and compared to numerical simulations. Ultimately, this will aid the testing and development of sub-grid-scale parameterizations for the multiple zonal jet regime that remain robust in the face of multiple forcing parameters. [1] Wordsworth, R. D., Read, P. L., & Yamazaki, Y. H. (2008). Turbulence, waves, and jets in a differentially heated rotating annulus experiment Physics of Fluids, 20(12), 126602.Streak photograph of suspended particles visualizing the flow representative of multiple zonal jets

  10. Modeling water regime in a small watershed

    Vogel, T.; Tesař, Miroslav; Císlerová, M.

    Praha: Ústav pro hydrodynamiku AV ČR, 2003 - (Šír, M.; Lichner, Ľ.; Tesař, M.), s. 127-136 ISBN 80-02-01586-X. [Hydrologie půdy v malém povodí. Praha (CZ), 15.10.2003] R&D Projects: GA AV ČR IAA3060001 Institutional research plan: CEZ:AV0Z2060917 Keywords : Soil water regime * Subsurface runoff generation * Rainfall-runoff event Subject RIV: DA - Hydrology ; Limnology

  11. REVIEW OF REGIME THEORY OF ALLUVIAL CHANNELS

    2002-01-01

    One of the most important problems in river engineering is to determine a stable cross section geomenry and slope for an alluvial channel. This has been the subject of considerable research for about a century and continues to be of great practical interest. Lgnoring plan geometry, an alluvi-al channel can adjust its slope, depth and width, to develop a dynamic stable condition in which it can transport a certain a-mount of water and sediment. The brief history of regime the-ory and its new development are reviewed in this paper.

  12. Bose polarons in the strongly interacting regime

    Hu, Ming-Guang; van de Graaff, Michael; Kedar, Dhruv; Cornell, Eric; Jin, Deborah

    Impurities immersed in and interacting with a Bose-Einstein condensate (BEC) are predicted to form quasiparticle excitations called Bose polarons. I will present experimental evidence of Bose polarons in cold atoms obtained using radio-frequency spectroscopy to measure the excitation spectrum of fermionic 40K impurities interacting with a BEC of 87Rb atoms. We use an interspecies Feshbach resonance to tune the interactions between the impurities and the bosons, and we take data in the strongly interacting regime. This work is supported by NSF, NASA and NIST.

  13. The Tributary Regime in the oil sector

    The tributary regime of the oil sector, is framed by the fiscal crisis that the country, maxim if one keeps in mind the importance of the fiscal revenues originated in the exploitation of these resources in Colombia, so much for the tribute coming from the foreign investment of the sector, like for the utilities generated by ECOPETROL and its impact in the public finances. However in front of this focus, the strategic importance of maintaining the investment in hydrocarbons and the paper that the fiscal politics and the tributary politics for the sector should play in the future and they constitute the government's key pieces

  14. Autoritarismus in Peru : das Fujimori-Regime

    Crabtree, John

    2007-01-01

    The ten-years presidency of Alberto Fujimori in Peru is a classic example of the sort of hybrid democracy that emerged in various Latin American countries in the 1990s, combining a mixture of democratic and clearly non-democratic elements. Fujimori was one of the more autocratic Latin American leaders of the 1990s, he is being the only regime formally to break with pre-existing constitutional rules. Closely tied to the military and intelligence apparatus, his government involved a concentrati...

  15. Random nanolasing in the Anderson localized regime

    Liu, Jin; Garcia, P. D.; Ek, Sara;

    2014-01-01

    multiple scattering. The applicability of random lasers has been limited due to multidirectional emission, lack of tunability, and strong mode competition with chaotic fluctuations due to a weak mode confinement. The regime of Anderson localization of light has been proposed for obtaining stable multimode...... random lasing, and initial work concerned macroscopic one-dimensional layered media. Here, we demonstrate on-chip random nanolasers where the cavity feedback is provided by the intrinsic disorder. The strong confinement achieved by Anderson localization reduces the spatial overlap between lasing modes...

  16. Privatised Keynesianism: An Unacknowledged Policy Regime

    Crouch, C.

    2009-01-01

    There have now been two successive policy regimes since the Second World War that have temporarily succeeded in reconciling the uncertainties and instabilities of a capitalist economy with democracy’s need for stability for people’s lives and capitalism’s own need for confident mass consumers. The first of these was the system of public demand management generally known as Keynesianism. The second was not, as has often been thought, a neo-liberal turn to pure markets, but a system of markets ...

  17. Asymptotic Regime in N Random Interacting Species

    Fiasconaro, A; Valenti, D

    2005-01-01

    The asymptotic regime of a complex ecosystem with N random interacting species and in the presence of an external multiplicative noise is analyzed. We find the role of the external noise on the long time probability distribution of the i_th density species, the extinction of species and the local field acting on the i_th population. We analyze in detail the transient dynamics of this field and the cavity field, which is the field acting on the i_th species when this is absent. We find that the presence or the absence of some population give different asymptotic distributions of these fields.

  18. Reconfigurable photoinduced metamaterials in the microwave regime

    Rizza, Carlo; De Paulis, Francesco; Palange, Elia; Orlandi, Antonio; Columbo, Lorenzo; Prati, Franco

    2014-01-01

    We investigate optically reconfigurable dielectric metamaterials at gigahertz frequencies. More precisely, we study the microwave response of a subwavelength grating optically imprinted into a semiconductor slab. In the homogenized regime, we analytically evaluate the ordinary and extraordinary component of the effective permittivity tensor by taking into account the photo-carrier dynamics described by the ambipolar diffusion equation. We analyze the impact of semiconductor parameters on the gigahertz metamaterial response which turns out to be highly reconfigurable by varying the photogenerated grating and which can show a marked anisotropic behavior.

  19. Asian Aspirations for Climate Regime Beyond 2012

    This report is based on the second round of 'The Asia-Pacific Consultations on Climate Regime Beyond 2012' in 2006 to further advance the frank exchange of opinions of policy makers, academics, and the private sector on specific issues of high priority to the region. These include: energy security and development, Clean Development Mechanism (CDM), technology development and transfer, and adaptation. This report presents a summary of what has been learnt through the current consultations, interviews, and questionnaire surveys with policy makers and climate policy researchers across the region

  20. Regulatory Regimes and Takeovers of U.S. Thrifts

    Fatma Cebenoyan; A. Sinan Cebenoyan; Elizabeth S. Cooperman

    2003-01-01

    This paper examines the effect of regulatory regime changes on the attributes of acquired thrifts for periods of stringency in 1990 to 1993, and deregulation in 1994 to 2000, with the removal of significant impediments for bank takeovers of thrifts. We test a regime change hypothesis that predicts a more effective takeover market in the later regime. Consistent with the hypothesis, we find bank acquirers to engage in diverse motivations for takeovers in the later regime, including revenue tur...

  1. The design of environmental regimes: Social construction, contextuality, and improvisation

    Lejano

    2006-01-01

    While much of the literature on environmental regimes has focused on effectiveness, this article takes a new look at a lesser-studied topic, the evolution of regime design. Understanding how regimes differ in design, and how various factors and processes shape such design, is important if we are to more carefully craft these regimes. We should also pay close attention to the formative role of social construction and context. Focusing on transboundary marine programs, we see that their designs...

  2. The role of the media in establishing international security regimes

    Chanan Naveh

    2005-01-01

    This article focuses primarily on the media's impact on international security regimes. It explores the ways in which the media affect the lifecycles of international regimes, from the time they are first conceived of, through their establishment, consolidation and stabilization, up until their ultimate demise. Although this paper highlights the media's role in the evolution of security regimes, it is clear that, regardless of the regime in question, media play a role throughout the lifecycle...

  3. Low-frequency regime transitions and predictability of regimes in a barotropic model

    Nadiga, B T

    2016-01-01

    Predictability of flow is examined in a barotropic vorticity model that admits low frequency regime transitions between zonal and dipolar states. Such transitions in the model were first studied by Bouchet and Simonnet (2009) and are reminiscent of regime change phenomena in the weather and climate systems wherein extreme and abrupt qualitative changes occur, seemingly randomly, after long periods of apparent stability. Mechanisms underlying regime transitions in the model are not well understood yet. From the point of view of atmospheric and oceanic dynamics, a novel aspect of the model is the lack of any source of background gradient of potential-vorticity such as topography or planetary gradient of rotation rate (e.g., as in Charney & DeVore '79). We consider perturbations that are embedded onto the system's chaotic attractor under the full nonlinear dynamics as bred vectors---nonlinear generalizations of the leading (backward) Lyapunov vector. We find that ensemble predictions that use bred vector per...

  4. The trade regime and the climate regime. Institutional evolution and adaptation

    This article addresses concerns that the multilateral trade regime centered in the WTO and the emerging climate regime may conflict in ways that could be damaging to either or both. The article discusses the institutional and diplomatic context of these concerns, and it identifies the kinds of issues that are in question. The analysis suggests that there are opportunities for win-win outcomes in the interactions of the two regimes, for instance in the possibility of reducing fossil fuel subsidies. However, there are also problematic areas where they intersect. A core issue-and as yet an unresolved one-is whether and how emission credit trading and other activities envisioned by the Kyoto Protocol would be subject to WTO rules. The resolution of this issue will affect many other issues as well. Additional specific issues about the interactions of particular provisions in WTO agreements and the Kyoto Protocol are analyzed in a subsequent companion article in Climate Policy

  5. Level-ARCH Short Rate Models with Regime Switching

    Christiansen, Charlotte

    This paper introduces regime switching volatility into level- ARCH models for the short rates of the US, the UK, and Germany. Once regime switching and level effects are included there are no gains from including ARCH effects. It is of secondary importance exactly how the regime switching is spec...

  6. Current status and key issues of nuclear liability regime

    Nuclear liability regime has been established from the beginning of the nuclear power industry. The first nuclear accident with major transboundary consequences occurred at Chernobyl, and led to reexamination of the nuclear liability regime. Current status and key issues of the national and international nuclear liability regime are reviewed. (author)

  7. The global nuclear safety regime and its impact in Brazil

    This work describes the Global Nuclear Safety Regime that was established worldwide after the accident at the Tchernobyl nuclear power plant. This regime is composed of biding international safety conventions, globally accepted safety standard, and a voluntary peer review system. The impact of this Global Regime in Brazil is also discussed. (Author)

  8. Change of secondary water regime of Paks NPP. Change of secondary water regime at Unit 2

    The installation of high pH water regime during the 17th cycle of Unit 2 aimed to decrease the amount of transportation inlet of erosion-corrosion products (magnitude) in feedwater to SGs. The resolution of OAH-NBI permitting the installation ordained to make an evaluation of the process. The main conclusions and results are discussed. The high pH water regime proved to be adequate in the case of Unit 2 as well, similarly to Units 3, 4 and 1. (R.P.)

  9. Strengthening the non proliferation regime: French views

    3 main issues can be identified in the French policy concerning the backing of non proliferation: 1) responding resolutely to proliferation crises, 2) reinforcing substantive efforts to prevent and impede proliferation, and 3) strengthening the non-proliferation regime. The first issue is very important because combating proliferation is vital to the security of all. Concerning the second issue, France attaches particular importance to strengthening specific measures to prevent and check proliferation. Let me mention a few proposals that we put forward: exports need to be controlled more effectively, proliferation activities have to be criminalized, or the development of proliferation-resistant technologies should be supported. Concerning the third issue it means the strengthening of the non-proliferation regime, France proposes several means: -) aiming at the universalization of the additional protocol; -) ensuring that the Agency continues to have sufficient human, financial and technical resources to fulfill its verification mission effectively; -) encouraging the IAEA to make full use of the authority available to it; -) enhancing the use of information relevant to the delivery of the IAEA mandate; and -) sharing more accurate information concerning the breaches of commitments that happen. The paper is followed by the slides of the presentation. (A.C.)

  10. Dynamic regimes of random fuzzy logic networks

    Random multistate networks, generalizations of the Boolean Kauffman networks, are generic models for complex systems of interacting agents. Depending on their mean connectivity, these networks exhibit ordered as well as chaotic behavior with a critical boundary separating both regimes. Typically, the nodes of these networks are assigned single discrete states. Here, we describe nodes by fuzzy numbers, i.e. vectors of degree-of-membership (DOM) functions specifying the degree to which the nodes are in each of their discrete states. This allows our models to deal with imprecision and uncertainties. Compatible update rules are constructed by expressing the update rules of the multistate network in terms of Boolean operators and generalizing them to fuzzy logic (FL) operators. The standard choice for these generalizations is the Goedel FL, where AND and OR are replaced by the minimum and maximum of two DOMs, respectively. In mean-field approximations we are able to analytically describe the percolation and asymptotic distribution of DOMs in random Goedel FL networks. This allows us to characterize the different dynamic regimes of random multistate networks in terms of FL. In a low-dimensional example, we provide explicit computations and validate our mean-field results by showing that they agree well with network simulations.

  11. Regimes of piezoelectric transformer operation II

    Piezoelectric transformers (PTs) have some attractive features for using them in power supply systems such as high efficiency and high power density, a high level of isolation between primary and secondary sides, a flat design which is well suited for a lot of applications and a low level of electromagnetic noise, just to name a few. For any application it is of utmost importance to know the behavior of a piezoelectric transformer under different conditions, which we call regimes of transformer operation. Based on this knowledge, criteria for safe operation of the PT in the power supply system and hence for the whole system as well can be derived. After having introduced the regimes of piezoelectric transformer operation in a first article on this topic in 2006 [1], in this paper we will present the derivation of important parameters based on measurements by way of an example of a symmetric PT. These measurements facilitate the basic understanding for choosing the appropriate transformer parameters necessary for its optimal as well as safe and controlled operation in power supply systems

  12. Elastic regimes of subisostatic athermal fiber networks

    Licup, A. J.; Sharma, A.; MacKintosh, F. C.

    2016-01-01

    Athermal models of disordered fibrous networks are highly useful for studying the mechanics of elastic networks composed of stiff biopolymers. The underlying network architecture is a key aspect that can affect the elastic properties of these systems, which include rich linear and nonlinear elasticity. Existing computational approaches have focused on both lattice-based and off-lattice networks obtained from the random placement of rods. It is not obvious, a priori, whether the two architectures have fundamentally similar or different mechanics. If they are different, it is not clear which of these represents a better model for biological networks. Here, we show that both approaches are essentially equivalent for the same network connectivity, provided the networks are subisostatic with respect to central force interactions. Moreover, for a given subisostatic connectivity, we even find that lattice-based networks in both two and three dimensions exhibit nearly identical nonlinear elastic response. We provide a description of the linear mechanics for both architectures in terms of a scaling function. We also show that the nonlinear regime is dominated by fiber bending and that stiffening originates from the stabilization of subisostatic networks by stress. We propose a generalized relation for this regime in terms of the self-generated normal stresses that develop under deformation. Different network architectures have different susceptibilities to the normal stress but essentially exhibit the same nonlinear mechanics. Such a stiffening mechanism has been shown to successfully capture the nonlinear mechanics of collagen networks.

  13. Dynamic regimes of random fuzzy logic networks

    Wittmann, Dominik M.; Theis, Fabian J.

    2011-01-01

    Random multistate networks, generalizations of the Boolean Kauffman networks, are generic models for complex systems of interacting agents. Depending on their mean connectivity, these networks exhibit ordered as well as chaotic behavior with a critical boundary separating both regimes. Typically, the nodes of these networks are assigned single discrete states. Here, we describe nodes by fuzzy numbers, i.e. vectors of degree-of-membership (DOM) functions specifying the degree to which the nodes are in each of their discrete states. This allows our models to deal with imprecision and uncertainties. Compatible update rules are constructed by expressing the update rules of the multistate network in terms of Boolean operators and generalizing them to fuzzy logic (FL) operators. The standard choice for these generalizations is the Gödel FL, where AND and OR are replaced by the minimum and maximum of two DOMs, respectively. In mean-field approximations we are able to analytically describe the percolation and asymptotic distribution of DOMs in random Gödel FL networks. This allows us to characterize the different dynamic regimes of random multistate networks in terms of FL. In a low-dimensional example, we provide explicit computations and validate our mean-field results by showing that they agree well with network simulations.

  14. Three novel tokamak plasma regimes in TFTR

    Aside from extending ''standard'' ohmic and neutral beam heating studies to advanced plasma parameters, TFTR has encountered a number of special plasma regimes that have the potential to shed new light on the physics of tokamak confinement and the optimal design of future D-T facilities: (1) High-powered, neutral beam heating at low plasma densities can maintain a highly reactive hot-ion population (with quasi-steady-state beam fueling and current drive) in a tokamak configuration of modest bulk-plasma confinement requirements. (2) Plasma displacement away from limiter contact lends itself to clarification of the role of edge-plasma recycling and radiation cooling within the overall pattern of tokamak heat flow. (3) Noncentral auxiliary heating (with a ''hollow'' power-deposition profile) should serve to raise the central tokamak plasma temperature without deterioration of central region confinement, thus facilitating the study of alpha-heating effects in TFTR. The experimental results of regime (3) support the theory that tokamak profile consistency is related to resistive kink stability and that the global energy confinement time is determined by transport properties of the plasma edge region

  15. Three novel tokamak plasma regimes in TFTR

    Furth, H.P.

    1985-10-01

    Aside from extending ''standard'' ohmic and neutral beam heating studies to advanced plasma parameters, TFTR has encountered a number of special plasma regimes that have the potential to shed new light on the physics of tokamak confinement and the optimal design of future D-T facilities: (1) High-powered, neutral beam heating at low plasma densities can maintain a highly reactive hot-ion population (with quasi-steady-state beam fueling and current drive) in a tokamak configuration of modest bulk-plasma confinement requirements. (2) Plasma displacement away from limiter contact lends itself to clarification of the role of edge-plasma recycling and radiation cooling within the overall pattern of tokamak heat flow. (3) Noncentral auxiliary heating (with a ''hollow'' power-deposition profile) should serve to raise the central tokamak plasma temperature without deterioration of central region confinement, thus facilitating the study of alpha-heating effects in TFTR. The experimental results of regime (3) support the theory that tokamak profile consistency is related to resistive kink stability and that the global energy confinement time is determined by transport properties of the plasma edge region.

  16. Tlatelolco regime and nonproliferation in Latin America

    The regime established by the Treaty of Tlatelolco supports peace and security in the Latin American region and global nonproliferation efforts. Circumstances leading to the creation of the nuclear-weapon-free zone include careful preparations and negotiations, individual leadership, existence of certain shared cultural and legal traditions of Latin American countries, and the temporary stimulus of the Cuban missile crisis. The lack of overt superpower pressure on Latin America, compared with more turbulent regions, has permitted continued progress toward full realization of the zone. Tlatelolco's negotiating process, as well as the substance of the Treaty, deserve careful consideration relative to other areas. The Treaty enjoys wide international approval, but full support by certain Latin American States (Argentina, Brazil, Chile, Cuba) has been negatively affected by the failure of the US Senate to ratify Tlatelolco's Protocol I. Nuclear programs of Argentina, Brazil, and Mexico are expanding rapidly and these nations are forming linkages with West European countries, rather than the United States. The May 1980 Argentine-Brazilian nuclear agreement foresees significant cooperation between the two nation's nuclear energy commissions and more coordinated resistance to the nuclear supplier countries. Argentine-Brazilian nuclear convergence and the response accorded to it by the United States will have significant implications for the future of the Tlatelolco regime and nonproliferation in Latin America. 52 references

  17. Elastic regimes of subisostatic athermal fiber networks.

    Licup, A J; Sharma, A; MacKintosh, F C

    2016-01-01

    Athermal models of disordered fibrous networks are highly useful for studying the mechanics of elastic networks composed of stiff biopolymers. The underlying network architecture is a key aspect that can affect the elastic properties of these systems, which include rich linear and nonlinear elasticity. Existing computational approaches have focused on both lattice-based and off-lattice networks obtained from the random placement of rods. It is not obvious, a priori, whether the two architectures have fundamentally similar or different mechanics. If they are different, it is not clear which of these represents a better model for biological networks. Here, we show that both approaches are essentially equivalent for the same network connectivity, provided the networks are subisostatic with respect to central force interactions. Moreover, for a given subisostatic connectivity, we even find that lattice-based networks in both two and three dimensions exhibit nearly identical nonlinear elastic response. We provide a description of the linear mechanics for both architectures in terms of a scaling function. We also show that the nonlinear regime is dominated by fiber bending and that stiffening originates from the stabilization of subisostatic networks by stress. We propose a generalized relation for this regime in terms of the self-generated normal stresses that develop under deformation. Different network architectures have different susceptibilities to the normal stress but essentially exhibit the same nonlinear mechanics. Such a stiffening mechanism has been shown to successfully capture the nonlinear mechanics of collagen networks. PMID:26871101

  18. Flow regime identification methodology with computerized tomography

    This work presents a flow identification methodology in multiphase system in stratified oil-water-gas regime. The principle is based on detecting the amount of x-rays attenuated by passing through the duct containing the flow. The radiation interacts with the material and the composite duct fluid, causing the intensity of X ray declines. In this study, was used divergent bean into two and three dimensions. In this case we need to know the source position in order to back project the rays accordingly in a divergent way. In three dimensions, the projections discontinuity determination problem is substituted by the projections images contour determination. Each ray generates one algebraic equation. The system may be solved by the least square method or by some algebraic reconstruction technique such as the ART, MART or q-ART algorithms. The experiment shows that with a single view (a source-detector pair) it is possible to obtain information of a flow inside a duct (the attenuation of the radiation beam). However, it is not possible to make the reconstruction of the flow. Then, we use two views, so getting enough information to reconstruct the flow. The results presented show that the technique may be applied in the successfully flow regime identification. (author)

  19. Flow regime identification methodology with computerized tomography

    Teixeira, Alberto Ramon Ferreira; Roberty, Nilson Costa, E-mail: ateixeira@con.ufrj.b, E-mail: nilson@nuclear.ufrj.b [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Nuclear Engineering Program

    2010-07-01

    This work presents a flow identification methodology in multiphase system in stratified oil-water-gas regime. The principle is based on detecting the amount of x-rays attenuated by passing through the duct containing the flow. The radiation interacts with the material and the composite duct fluid, causing the intensity of X ray declines. In this study, was used divergent bean into two and three dimensions. In this case we need to know the source position in order to back project the rays accordingly in a divergent way. In three dimensions, the projections discontinuity determination problem is substituted by the projections images contour determination. Each ray generates one algebraic equation. The system may be solved by the least square method or by some algebraic reconstruction technique such as the ART, MART or q-ART algorithms. The experiment shows that with a single view (a source-detector pair) it is possible to obtain information of a flow inside a duct (the attenuation of the radiation beam). However, it is not possible to make the reconstruction of the flow. Then, we use two views, so getting enough information to reconstruct the flow. The results presented show that the technique may be applied in the successfully flow regime identification. (author)

  20. Essence and Prospect of International Export Control Regimes

    2005-01-01

    @@ International export control regimes are referring to the regimes and systems concerning limitation of export and transference of military-use and dual-use items and related parts as well as technologies. In the past couple of years, the control regimes have shown a strengthening posture. In addition, a new global export control regime is brewing. Hence export control has caught the attention of the international community, and particularly of the circles of armament control and commerce. The author would like to make some analyses of the posture and then try to predict the trend of international export control regimes.

  1. Quaternary Faults and Stress Regime of Venezuela

    F.A. Audemard M.

    2006-12-01

    Full Text Available Spatial configuration of Quaternary active tectonic features along the southern Caribbean plate boundary suggests that the region is subject to a compressive strike-slip (transpressional senso lato regime, characterized by a NNW-SSE maximum horizontal stress (sH=s1 and/or an ENE-WSW minimum (s h=s3 or s2 horizontal stress. Stress inversion applied to fault-plane kinematic indicators measured essentially in Plio-Quaternary sedimentary rocks confirms this tectonic regime. Accordingly, this stress regime is responsible for the Quaternary activity and kinematics of six sets of brittle features along northern Venezuela (from Colombia in the west to Trinidad in the east: (1 east-west rightlateral faults, (2 NW right-lateral faults -acting as synthetic Riedel shears-, (3 ENE to east-west dextral faults -P shears-, (4 NNW normal faults, (5 almost north-south left-lateral faults -antithetic Riedel shears- and (6 mostly subsurface ENE reverse faults associated with folding of the same orientation. Brittle deformation conforms to the simple shear model, although not all the deformation can be accounted for it since strain partitioning is also taking place because regional folding and thrusting are due to the normal-to-structure component of the relative slip vector between the Caribbean and South America plates. On the other hand, the maximum horizontal stress in western Venezuela, particularly in the Maracaibo block and south of the Oca-Ancón fault, progressively turns counter-clockwise to become more east-west oriented, producing left- and right-lateral slip along the north-south striking and NE-SW striking faults, respectively. The orientation and spatial variation of this regional stress field in western Venezuela results from the superposition of the two major neighboring interplate maximum horizontal stress orientations (sH: roughly east-west trending stress across the Nazca-South America type-B subduction along the pacific coast of Colombia and NNW

  2. Progress towards a global nuclear liability regime

    As the production and use of nuclear energy for peaceful purposes developed in the 1950s, a specific legal framework for third party nuclear liability was established to ensure adequate compensation for damage to persons and property resulting from a nuclear accident, but also to encourage the industry to develop nuclear technology and assume responsibility without being exposed to an uncertain and potentially ruinous liability burden. Significant attention has been understandably placed at the international and national levels on fostering strong programmes to achieve safety, security and safeguards at a high level. Notwithstanding best efforts to achieve a high level of safety, the possibility remains that accidents may occur within a nuclear installation (i.e. not only nuclear power plants but also any installation in which there are nuclear fuel, nuclear substances, radioactive products or waste) or during the transportation of nuclear substances to or from a nuclear installation. As the experience shows from the accidents that occurred at Three Mile Island (United States) in 1979, Chernobyl (former USSR) in 1986, and Fukushima Daiichi (Japan) in 2011, severe accidents can have varying and potentially far-reaching consequences affecting both people and property. In the wake of the Fukushima Daiichi nuclear power plant accident, the General Conference of the International Atomic Energy Agency (IAEA) endorsed in September 2011 an Action Plan on Nuclear Safety (“IAEA Action Plan”) to strengthen the global nuclear safety framework. The IAEA Action Plan calls upon member states “to work towards establishing a global nuclear liability regime that addresses the concerns of all states that might be affected by a nuclear accident with a view to providing appropriate compensation for nuclear damage”, and “to give due consideration to the possibility of joining the international nuclear liability instruments as a step towards achieving such a global regime

  3. Institutional design and regime effectiveness in transboundary river management – the Elbe water quality regime

    I. Dombrowsky

    2007-06-01

    Full Text Available The literature on transboundary river management suggests that institutions play an important role in bringing cooperation about. However, the knowledge on how they should be designed in order to do so remains limited. One way to learn more about adequate institutional design is to assess the effectiveness of existing regimes, and to trace the causal relationships leading to the respective outcomes. In order to gain further insights into the relationship of institutional design and regime effectiveness, this paper presents a study on the water quality regime of the International Commission for the Protection of the Elbe (ICPE. The analysis is based on a review of pertinent documents and ten qualitative interviews with Czech and German Commission members and NGO representatives. Particular emphasis has been put on determining the ICPE's specific contribution and the no-regime counterfactual as well as on the perceived expedience of the institutional arrangements. The study shows that overall due to external as well as internal institutional factors the ICPE proved relatively successful, and as such it also provides insights into how institutions matter: The commission served as platform for joint problem solving by identifying priorities for action. These international obligations increased the power of national administrations and their access to funds. At the same time, the Commission's reporting to the public served as an enforcement mechanism. However, the ICPE's contribution towards achieving the various goals varied significantly between the different areas of activity. It was high where the main responsibility for action was with the public authorities, such as in the area of wastewater treatment and the establishment of an international alarm plan and model. It was practically non existent in the reduction of non-point pollution from agriculture, where the success depended on the behavior of individual private actors (farmers. From a

  4. Regime shifts in models of dryland vegetation

    Zelnik, Yuval R; Yizhaq, Hezi; Bel, Golan; Meron, Ehud

    2013-01-01

    Drylands are pattern-forming systems showing self-organized vegetation patchiness, multiplicity of stable states and fronts separating domains of alternative stable states. Pattern dynamics, induced by droughts or disturbances, can result in desertification shifts from patterned vegetation to bare soil. Pattern-formation theory suggests various scenarios for such dynamics; an abrupt global shift involving a fast collapse to bare soil, a gradual global shift involving the expansion and coalescence of bare-soil domains, and an incipient shift to a hybrid state consisting of stationary bare-soil domains in an otherwise periodic pattern. Using models of dryland vegetation we address the question which of these scenarios can be realized. We found that the models can be split into two groups: models that exhibit multiplicity of periodic-pattern and bare-soil states, and models that exhibit, in addition, multiplicity of hybrid states. Furthermore, in all models we could not identify parameter regimes in which bare-s...

  5. Two regimes of forced turbulent convection

    Eidelman, A; Kleeorin, N; Rogachevskii, I; Sapir-Katiraie, I

    2009-01-01

    We study experimentally a forced turbulent convection in the Rayleigh-B\\'{e}nard apparatus with an additional source of turbulence produced by the two oscillating grids located nearby the side walls of the chamber. Two different regimes have been observed in the forced turbulent convection. When the frequency of the grid oscillations f>2 Hz, the large-scale circulation (LSC) is totally destroyed, and the destruction of the LSC is accompanied by a strong change of the mean temperature distribution. For the very low frequency the thermal structure inside the LSC is inhomogeneous and anisotropic. The hot thermal plumes accumulate at one side of LSC, and cold plumes concentrate at the opposite side of LSC. The mean temperature gradient in the horizontal direction inside the LSC is significantly larger than in the vertical direction. For the high frequency (f > 10 Hz), LSC has not been observed and the mean temperature gradient in the central flow region in the vertical direction, \

  6. The Great Lakes' regional climate regimes

    Sugiyama, Noriyuki

    For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

  7. Environment Flow Assessment with Flow Regime Transition

    Su, J.; Ho, C. C.; Chang, L. C.

    2015-12-01

    To avoid worsen river and estuarine ecosystems cause by overusing water resources, environmental flows conservation is applied to reduce the impact of river environment. Environmental flows refer to water provided within a river, wetland or coastal zone to sustain ecosystems and benefits to human wellbeing. Environment flow assessment is now widely accepted that a naturally variable flow regime, rather than just a minimum low flow. In this study, we propose four methods, experience method, Tenant method, hydraulic method and habitat method to assess the environmental flow of base flow, flush flow and overbank flow with different discharge, frequency and occurrence period. Dahan River has been chosen as a case to demonstrate the assessment mechanism. The alternatives impact analysis of environment and human water used provides a reference for stakeholders when holding an environmental flow consultative meeting.

  8. Deterministic-random separation in nonstationary regime

    Abboud, D.; Antoni, J.; Sieg-Zieba, S.; Eltabach, M.

    2016-02-01

    In rotating machinery vibration analysis, the synchronous average is perhaps the most widely used technique for extracting periodic components. Periodic components are typically related to gear vibrations, misalignments, unbalances, blade rotations, reciprocating forces, etc. Their separation from other random components is essential in vibration-based diagnosis in order to discriminate useful information from masking noise. However, synchronous averaging theoretically requires the machine to operate under stationary regime (i.e. the related vibration signals are cyclostationary) and is otherwise jeopardized by the presence of amplitude and phase modulations. A first object of this paper is to investigate the nature of the nonstationarity induced by the response of a linear time-invariant system subjected to speed varying excitation. For this purpose, the concept of a cyclo-non-stationary signal is introduced, which extends the class of cyclostationary signals to speed-varying regimes. Next, a "generalized synchronous average'' is designed to extract the deterministic part of a cyclo-non-stationary vibration signal-i.e. the analog of the periodic part of a cyclostationary signal. Two estimators of the GSA have been proposed. The first one returns the synchronous average of the signal at predefined discrete operating speeds. A brief statistical study of it is performed, aiming to provide the user with confidence intervals that reflect the "quality" of the estimator according to the SNR and the estimated speed. The second estimator returns a smoothed version of the former by enforcing continuity over the speed axis. It helps to reconstruct the deterministic component by tracking a specific trajectory dictated by the speed profile (assumed to be known a priori).The proposed method is validated first on synthetic signals and then on actual industrial signals. The usefulness of the approach is demonstrated on envelope-based diagnosis of bearings in variable

  9. The role of the media in establishing international security regimes

    Chanan Naveh

    2005-04-01

    Full Text Available This article focuses primarily on the media's impact on international security regimes. It explores the ways in which the media affect the lifecycles of international regimes, from the time they are first conceived of, through their establishment, consolidation and stabilization, up until their ultimate demise. Although this paper highlights the media's role in the evolution of security regimes, it is clear that, regardless of the regime in question, media play a role throughout the lifecycle of all international regimes, whatever their character. In order to analyze the relationships of the media with security regimes in general, and specifically their contribution to each stage in their development, the article utilizes methodologies from the field of communication studies. It examines the media's agenda, "news values" and various functions, and their ability to mobilize public support for the particular issue of the regime. To date, most studies have explored the interaction between media communication patterns and global developments at the state level, or in relation to the formulation of foreign policy, while largely ignoring the international dimension of the relationship. This article attempts to remedy this situation, and the relevant processes are analysed in a case study of the anti-Iraq international security regime. It should be noted that although the paper focuses on the specific anti-Iraqi regime, it is part of a more general Anti-Rogue actors regime which includes the war against global terrorism. The study of the development of the anti-Iraq press-security regime teaches us that during international crises the media mobilize and unanimously support the regime fighting the "bad guys." But, when the regime develops and enters disputed turfs and begins to lose its legitimacy, media support diminishes, and the media may even develop into an opposing force and may join the actors fighting against this regime. Moreover, the study of

  10. Spacetime-noncommutativity regime of Loop Quantum Gravity

    AMELINO-CAMELIA, Giovanni; da Silva, Malú Maira; Ronco, Michele; Cesarini, Lorenzo; Lecian, Orchidea Maria

    2016-01-01

    A recent study by Bojowald and Paily provided a path toward the identification of an effective quantum-spacetime picture of Loop Quantum Gravity, applicable in the "Minkowski regime", the regime where the large-scale (coarse-grained) spacetime metric is flat. A pivotal role in the analysis is played by Loop-Quantum-Gravity-based modifications to the hypersurface deformation algebra, which leave a trace in the Minkowski regime. We here show that the symmetry-algebra results reported by Bojowal...

  11. Apparel exportism in Kenya: international regimes, chain governance and upgrading

    Kindiki, M. M.

    2011-01-01

    An important question in development is how far can the contemporary global context create industrial development opportunities for the South, particularly for Low Income Countries? In an important sense, this can only be answered in non-abstract terms, since the institutional conditions facing particular industries at particular times are highly specific. In this research, a configuration of four regimes- the structural regime on production and trade in apparel, the labour regime, the neo-st...

  12. Exchange Rate Regime Analysis Using Structural Change Methods

    Zeileis, Achim; Shah, Ajay; Patnaik, Ila

    2007-01-01

    Regression models for de facto currency regime classification are complemented by inferential techniques for tracking the stability of exchange rate regimes. Several structural change methods are adapted to these regressions: tools for assessing the stability of exchange rate regressions in historical data (testing), in incoming data (monitoring) and for determining the breakpoints of shifts in the exchange rate regime (dating). The tools are illustrated by investigating the Chinese exchange ...

  13. Fixed or Floating Exchange Regimes; Does it Matter for Inflation?

    Peter J. Quirk

    1994-01-01

    This paper reviews recent experience with the choice of floating or fixed (“anchor”) exchange regimes in industrial and developing countries. It concludes that desirable differences between the two sets of regimes have narrowed, owing to the useful operational role of exchange rate margins and unavoidable medium-term rate adjustments in the context of fixed regimes. A survey of recent empirical cross-country literature also suggests little unambiguous association of the choice of exchange reg...

  14. Detection and Assessment of Ecosystem Regime Shifts from Fisher Information

    B. Roy Frieden; Christopher W. Pawlowski; Heriberto Cabezas; Arunprakash T. Karunanithi

    2008-01-01

    Ecosystem regime shifts, which are long-term system reorganizations, have profound implications for sustainability. There is a great need for indicators of regime shifts, particularly methods that are applicable to data from real systems. We have developed a form of Fisher information that measures dynamic order in complex systems. Here we propose the use of Fisher information as a means of: (1) detecting dynamic regime shifts in ecosystems, and (2) assessing the quality of the shift in terms...

  15. Scaling regimes in spherical shell rotating convection

    Gastine, T; Aubert, J

    2016-01-01

    Rayleigh-B\\'enard convection in rotating spherical shells can be considered as a simplified analogue of many astrophysical and geophysical fluid flows. Here, we use three-dimensional direct numerical simulations to study this physical process. We construct a dataset of more than 200 numerical models that cover a broad parameter range with Ekman numbers spanning $3\\times 10^{-7} \\leq E \\leq 10^{-1}$, Rayleigh numbers within the range $10^3 < Ra < 2\\times 10^{10}$ and a Prandtl number unity. We investigate the scaling behaviours of both local (length scales, boundary layers) and global (Nusselt and Reynolds numbers) properties across various physical regimes from onset of rotating convection to weakly-rotating convection. Close to critical, the convective flow is dominated by a triple force balance between viscosity, Coriolis force and buoyancy. For larger supercriticalities, a subset of our numerical data approaches the asymptotic diffusivity-free scaling of rotating convection $Nu\\sim Ra^{3/2}E^{2}$ in ...

  16. On the ontological emergence from quantum regime

    Luty, Damian [Adam Mickiewicz University, Poznan (Poland)

    2014-07-01

    There are several views on the relation between quantum physics and theory of relativity (especially General Relativity, GR). A popular perspective is this: GR with its macroscopic gravitational effects will turn out to be a limit of a more fundamental theory which should consider discrete physics and not deal with continuity (like theory of relativity). Thus, GR will emerge from a more basic theory, which should be quantum-like. One could call this an epistemic emergence view towards fundamental theories. The question is, given that scientific realism is valid: should emergence be a fundamental notion in our ontological view about the evolving, physical Universe? Is there an ontological emergence fully compatible with the notion of fundamentality? I argue that if we want to defend ontological emergence (from quantum to macroscopic regime) as something fundamental, we will arrive at the position of metaphysics of dispositions (and I argue, why this is undesirable), or conclude, that we cannot square fully fundamental ontology with the notion of emergence, and that we have to accept an ontological pluralism relativised to a certain scale. I defend the latter proposition, showing, that epistemic emergence doesn't entail (logically) ontological emergence.

  17. On the ontological emergence from quantum regime

    There are several views on the relation between quantum physics and theory of relativity (especially General Relativity, GR). A popular perspective is this: GR with its macroscopic gravitational effects will turn out to be a limit of a more fundamental theory which should consider discrete physics and not deal with continuity (like theory of relativity). Thus, GR will emerge from a more basic theory, which should be quantum-like. One could call this an epistemic emergence view towards fundamental theories. The question is, given that scientific realism is valid: should emergence be a fundamental notion in our ontological view about the evolving, physical Universe? Is there an ontological emergence fully compatible with the notion of fundamentality? I argue that if we want to defend ontological emergence (from quantum to macroscopic regime) as something fundamental, we will arrive at the position of metaphysics of dispositions (and I argue, why this is undesirable), or conclude, that we cannot square fully fundamental ontology with the notion of emergence, and that we have to accept an ontological pluralism relativised to a certain scale. I defend the latter proposition, showing, that epistemic emergence doesn't entail (logically) ontological emergence.

  18. Revamp urged for Norway's offshore regime

    This paper reports that the Norwegian government has come under renewed pressure from offshore operators to fine tune its licensing procedures and tax regime. The need for change was emphasized at the Advanced Petroleum Conference in Stavanger attended by senior personnel from companies active in the Norwegian and British sectors of the North Sea. Companies have had some success in the tax front, winning changes in proposals from Norway's Ministry of Finance for offshore tax reform. The changes were required to offset a general reduction in the corporate tax to 28% from 50.8%. Norsk Shell has told the government that in view of uncertainty about taxes it will not take part in the normal industry-government discussions about what acreage should be included in the 14th licensing round to be announced next year. This action does not bar Shell from participating in the licensing round when it gets under way. Shell has the if the tax package is not changed sharply in its passage through Storting it is unlikely to bid for new licenses

  19. Multimode optomechanical system in the quantum regime

    Nielsen, William H P; Møller, Christoffer B; Polzik, Eugene S; Schliesser, Albert

    2016-01-01

    We realise a simple and robust optomechanical system with a multitude of long-lived ($Q>10^7$) mechanical modes in a phononic-bandgap shielded membrane resonator. An optical mode of a compact Fabry-Perot resonator detects these modes' motion with a measurement rate ($96~\\mathrm{kHz}$) that exceeds the mechanical decoherence rates already at moderate cryogenic temperatures ($10\\,\\mathrm{K}$). Reaching this quantum regime entails, i.~a., quantum measurement backaction exceeding thermal forces, and thus detectable optomechanical quantum correlations. In particular, we observe ponderomotive squeezing of the output light mediated by a multitude of mechanical resonator modes, with quantum noise suppression up to -2.4 dB (-3.6 dB if corrected for detection losses) and bandwidths $\\lesssim 90\\,\\mathrm{ kHz}$. The multi-mode nature of the employed membrane and Fabry-Perot resonators lends itself to hybrid entanglement schemes involving multiple electromagnetic, mechanical, and spin degrees of freedom.

  20. On spinfoam models in large spin regime

    We study the semiclassical behavior of Lorentzian Engle–Pereira–Rovelli–Livine (EPRL) spinfoam model, by taking into account the sum over spins in the large spin regime. We also employ the method of stationary phase analysis with parameters and the so-called, almost analytic machinery, in order to find the asymptotic behavior of the contributions from all possible large spin configurations in the spinfoam model. The spins contributing the sum are written as Jf = λjf, where λ is a large parameter resulting in an asymptotic expansion via stationary phase approximation. The analysis shows that at least for the simplicial Lorentzian geometries (as spinfoam critical configurations), they contribute the leading order approximation of spinfoam amplitude only when their deficit angles satisfy γ Θ-ring f≤λ−1/2 mod 4πZ. Our analysis results in a curvature expansion of the semiclassical low energy effective action from the spinfoam model, where the UV modifications of Einstein gravity appear as subleading high-curvature corrections. (paper)

  1. Global fishery prospects under contrasting management regimes.

    Costello, Christopher; Ovando, Daniel; Clavelle, Tyler; Strauss, C Kent; Hilborn, Ray; Melnychuk, Michael C; Branch, Trevor A; Gaines, Steven D; Szuwalski, Cody S; Cabral, Reniel B; Rader, Douglas N; Leland, Amanda

    2016-05-01

    Data from 4,713 fisheries worldwide, representing 78% of global reported fish catch, are analyzed to estimate the status, trends, and benefits of alternative approaches to recovering depleted fisheries. For each fishery, we estimate current biological status and forecast the impacts of contrasting management regimes on catch, profit, and biomass of fish in the sea. We estimate unique recovery targets and trajectories for each fishery, calculate the year-by-year effects of alternative recovery approaches, and model how alternative institutional reforms affect recovery outcomes. Current status is highly heterogeneous-the median fishery is in poor health (overfished, with further overfishing occurring), although 32% of fisheries are in good biological, although not necessarily economic, condition. Our business-as-usual scenario projects further divergence and continued collapse for many of the world's fisheries. Applying sound management reforms to global fisheries in our dataset could generate annual increases exceeding 16 million metric tons (MMT) in catch, $53 billion in profit, and 619 MMT in biomass relative to business as usual. We also find that, with appropriate reforms, recovery can happen quickly, with the median fishery taking under 10 y to reach recovery targets. Our results show that commonsense reforms to fishery management would dramatically improve overall fish abundance while increasing food security and profits. PMID:27035953

  2. Regime shifts in a social-ecological system

    Lade, Steven J.; Tavoni, Alessandro; Levin, Simon A.; Schlüter, Maja

    2013-01-01

    Ecological regime shifts are rarely purely ecological. Not only is the regime shift frequently triggered by human activity, but the responses of relevant actors to ecological dynamics are often crucial to the development and even existence of the regime shift. Here, we show that the dynamics of human behaviour in response to ecological changes can be crucial in determining the overall dynamics of the system. We find a social-ecological regime shift in a model of harvesters of a common-pool re...

  3. Institutional design and regime effectiveness in transboundary river management – the Elbe water quality regime

    I. Dombrowsky

    2008-02-01

    Full Text Available The literature on transboundary river management suggests that institutions play an important role in bringing about cooperation. However, knowledge about how such institutions should be designed in order to do so remains limited. One way to learn more about adequate institutional design is to assess the effectiveness of existing regimes, and to trace the causal relationships that lead to the respective outcomes. In order to gain further insights into the relationship between institutional design and regime effectiveness, this paper presents a study on the water quality regime of the International Commission for the Protection of the Elbe (ICPE. The analysis is based on a review of pertinent documents and ten qualitative interviews with Czech and German Commission members and NGO representatives. Particular emphasis has been put on determining the ICPE's specific contribution and the no-regime counterfactual as well as on the perceived expediency of the institutional arrangements. The study shows overall that the countries were relatively successful in improving water quality in the Elbe basin. However, this outcome can only partly be attributed to the ICPE itself. Furthermore, the ICPE's contribution towards achieving the various goals varied significantly between the different areas of activity: it was relatively significant where the main responsibility for action lay with the public authorities, such as in the area of wastewater treatment and the establishment of an international alarm plan and model, but was practically non-existent in the reduction of non-point pollution from agriculture, where success depended on the behavior of individual private actors (farmers. The commission contributed towards problem solving by serving as a forum for the joint identification of priorities for action from a basin-wide perspective. The resulting international obligations increased the power of national water administrations and their access to funds

  4. Varieties of Economic Growth Regimes, Types of Macroeconomic Policies, and Policy Regime: A Post-Keynesian Analysis

    Hiroshi Nishi

    2012-01-01

    This study explores the effects of macroeconomic policies on measures of macroeconomic performance such as growth and inflation by setting up a dynamic post-Keynesian model with government and central bank interventions. In doing so, this study reconsiders the arguments in favor of a policy regime. The model in this paper generates several varieties of economic growth regimes and inflation dynamics. The economic growth regimes are defined by the relationship between economic growth, the incom...

  5. Co-evolution of waste and electricity regimes: Multi-regime dynamics in the Netherlands (1969-2003)

    This article explores how the relation between waste and electricity regimes changed in the Netherlands in a long-term perspective. The concept of socio-technical regime is used to investigate institutional, technological and social (network) changes. The conclusion is that the relationship changed from two regimes being separated into a much more symbiotic and integrated relationship through a multi-level and co-evolutionary process. The concept of 'biomass' has become a binding element in the relationship

  6. MRS2_PLOT: MATLAB function to plot calibration results for a Markov regime-switching (MRS) model with 2 regimes.

    Joanna Janczura; Rafal Weron

    2011-01-01

    MRS2_PLOT(KSI_TT,DATA) generates a figure with two panels visualizing calibration results for a Markov regime-switching (MRS) model with 2 regimes fitted to time series DATA. In the bottom panel probabilities KSI_TT that an observation comes from the spike (i.e. second) regime are plotted. In the top panel the time series is displayed with observations identified as belonging to the spike regime (i.e. having KSI_TT>0.5) marked by red dots. MRS2_PLOT(KSI_TT,DATA,YLAB,XLAB,TIT,POS) allows to sp...

  7. The seismology of geothermal regimes. Final report

    Aki, K.

    1997-04-01

    The authors have been developing seismological interpretation theory and methods applicable to complex structures encountered in geothermal areas for a better understanding of the earth`s geothermal regimes. The questions the y have addressed in their research may be summarized as ``What is going on in the earth`s crust under tectonically active regions; what are the structures and processes responsible for such activities as earthquakes and volcanic eruptions; and how can one capture their essence effectively by means of seismological studies?`` First, the authors found clear evidence for localization of scattered seismic energy in the deep magmatic system of the volcano on the island of Reunion in the Indian Ocean. The seismic coda of local earthquakes show concentrated energy in the intrusive zones as late as 30 to 40 seconds after the origin time. This offers a very effective method for defining a zone of strong heterogeneity on a regional scale, complementary to the high resolution study using trapped modes as pursued in the past project. Secondly, the authors identified about 700 long-period events with various frequencies and durations from the data collected during the past 5 years which included three episodes of eruption. They are applying a finite-element method to the simplest event with the longest period and the shortest duration in order to find the location, geometry and physical properties of their source deterministically. The preliminary result described here suggests that their sources may be a horizontally lying magma-filled crack at a shallow depth under the summit area. In addition to the above work on the Reunion data, they have continued the theoretical and observational studies of attenuation and scattering of seismic waves.

  8. Dissipation regimes for short wind waves

    Caulliez, Guillemette

    2013-02-01

    The dissipation processes affecting short wind waves of centimeter and decimeter scales are investigated experimentally in laboratory. The processes include damping due to molecular viscosity, generation of capillary waves, microbreaking, and breaking. The observations were made in a large wind wave tank for a wide range of fetches and winds, using a laser sheet and a high-resolution video camera. The work aims at constructing a comprehensive picture of dissipative processes in the short wind wave field, to find for which scales particular dissipative mechanism may become important. Four distinct regimes have been identified. For capillary-gravity wave fields, i.e., for dominant waves with scales below 4 cm, viscous damping is found to be the main dissipation mechanism. The gravity-capillary wave fields with dominant wavelength less than 10 cm usually exhibit a train of capillary ripples at the crest wavefront, but no wave breaking. For such waves, the main dissipation process is molecular viscosity occurring through nonlinear energy cascade toward high-frequency motions. Microscale breaking takes place for waves longer than 10 cm and manifests itself in a very localized surface disruption on the forward face of the crest. Such events generate turbulent motions in water and thus enhance wave dissipation. Plunging breaking, characterized by formation of a crest bulge, a microjet hitting the water surface and a splash-up, occurs for short gravity waves of wavelength exceeding 20 cm. Macroscale spilling breaking is also observed for longer waves at high winds. In both cases, the direct momentum transfer from breaking waves to the water flow contributes significantly to wave damping.

  9. Antecedents of Teachers Fostering Effort within two different management regimes: An assessment-based accountability regime and regime without external pressure on results

    Knut-Andreas Christophersen; Eyvind Elstad; Are Turmo

    2012-01-01

    This article focuses on the comparison of organizational antecedents of teachers' fostering of students' effort in two quite different accountability regimes: one management regime with an external-accountability system and one with no external accountability devices. The methodology involves cross-sectional surveys from two different management systems: (1) teachers working under assessment-based accountability (N = 236) and (2) folk–high school teachers who work without tests and examinatio...

  10. Antecedents of Teachers Fostering Effort within two different management regimes: An assessment-based accountability regime and regime without external pressure on results

    Knut-Andreas Christophersen

    2012-12-01

    Full Text Available This article focuses on the comparison of organizational antecedents of teachers' fostering of students' effort in two quite different accountability regimes: one management regime with an external-accountability system and one with no external accountability devices. The methodology involves cross-sectional surveys from two different management systems: (1 teachers working under assessment-based accountability (N = 236 and (2 folk–high school teachers who work without tests and examinations and, thereby, without external accountability devices (N = 366. The purpose of the study is to estimate the path coefficients in structural equation modeling in the two regimes and compare the significance of relationships between concepts in the structural models. Through this comparison, inferences are drawn suggesting how accountability repercussions and other leadership organizational antecedents may influence teachers' fostering of students' efforts and how qualitative aspects among school professionals may influence the fostering of effort. Implications for practice and directions for future research are discussed.Christopherson, K, Elstad, E, & Turmo, A. (2012. Antecedents of teachers fostering effort within two different management regimes: an assessment-based accountability regime and regime without external pressure on results. International Journal of Education Policy and Leadership 7(6. Retrieved from www.ijepl.org.

  11. Plasma Physics Regimes in Tokamaks with Li Walls

    Low recycling regimes with a plasma limited by a lithium wall surface suggest enhanced stability and energy confinement, both necessary for tokamak reactors. These regimes could make ignition feasible in compact tokamaks. Ignited Spherical Tokamaks (IST), self-sufficient in the bootstrap current, are introduced as a necessary step for development of the physics and technology of power reactors

  12. Disciplinary Regimes of "Care" and Complementary Alternative Education

    Thomson, Pat; Pennacchia, Jodie

    2016-01-01

    In schools, the notion of "care" is often synonymous with welfare and disciplinary regimes. Drawing on Foucault, and a study of alternative education (AE) across the UK, and looking in depth at two cases of complementary AE, we identify three types of disciplinary regimes at work in schools: (1) dominant performative reward and…

  13. Transition to ballistic regime for heat transport in helium II

    The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter–Mellinck regime of turbulent superfluids, is extended to describe the transition to ballistic regime in narrow channels wherein the radius R is comparable to (or smaller than) the phonon mean-free path ℓ in superfluid helium. To do so, we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to R2 (Landau regime) to another one proportional to Rℓ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates. - Highlights: • Heat transport in counterflow helium in the ballistic regime. • The one-fluid model based on the Extended Thermodynamics is used. • The transition from the Landau regime to the ballistic regime. • The transition from quantum turbulence to ballistic regime

  14. Molecular dynamics of flows in the Knudsen regime

    Cieplak, Marek; Koplik, Joel; Banavar, Jayanth R.

    2000-01-01

    Novel technological applications often involve fluid flows in the Knudsen regime in which the mean free path is comparable to the system size. We use molecular dynamics simulations to study the transition between the dilute gas and the dense fluid regimes as the fluid density is increased.

  15. Extractive Regimes: Toward a Better Understanding of Indonesian Development

    Gellert, Paul K.

    2010-01-01

    This article proposes the concept of an extractive regime to understand Indonesia's developmental trajectory from 1966 to 1998. The concept contributes to world-systems, globalization, and commodity-based approaches to understanding peripheral development. An extractive regime is defined by its reliance on extraction of multiple natural resources…

  16. Transition to ballistic regime for heat transport in helium II

    Sciacca, Michele, E-mail: michele.sciacca@unipa.it [Dipartimento Scienze Agrarie e Forestali, Università degli studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Sellitto, Antonio, E-mail: ant.sellitto@gmail.com [Dipartimento di Matematica, Informatica ed Economia, Università della Basilicata, Campus Macchia Romana, 85100 Potenza (Italy); Jou, David, E-mail: david.jou@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain)

    2014-07-04

    The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter–Mellinck regime of turbulent superfluids, is extended to describe the transition to ballistic regime in narrow channels wherein the radius R is comparable to (or smaller than) the phonon mean-free path ℓ in superfluid helium. To do so, we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to R{sup 2} (Landau regime) to another one proportional to Rℓ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates. - Highlights: • Heat transport in counterflow helium in the ballistic regime. • The one-fluid model based on the Extended Thermodynamics is used. • The transition from the Landau regime to the ballistic regime. • The transition from quantum turbulence to ballistic regime.

  17. Bargaining among Nations: Culture, History, and Perceptions in Regime Formation.

    Lipschutz, Ronnie D.

    1991-01-01

    The formation of regimes (collective international schemes) for managing global problems depends on culture, history, and perceptions. The ways in which these elements affect bargaining among nations over issues of the global commons are discussed. Implications are reviewed for a regime to deal with atmospheric conditions and global warming. (SLD)

  18. Policy Ideas, Knowledge Regimes and Comparative Political Economy

    Campbell, John L.; Pedersen, Ove K.

    2015-01-01

    Despite much attention to how ideas affect policy making, where these ideas come from is a blind spot in comparative political economy. We show that an important source of policy ideas are knowledge regimes—fields of policy research organizations. We show as well that the organization of knowledge...... regimes is heavily influenced by the organization of their surrounding political economies such that knowledge regimes have particular national characters. Furthermore, when people perceive that the utility of their knowledge regime for the rest of the political economy breaks down, they often try to...... restore it by transforming their knowledge regimes, albeit in ways that are still shaped by the surrounding political and economic institutions. The effectiveness of their efforts is not guaranteed. The argument is based on an analysis of the evolution of knowledge regimes since the 1970s in the USA...

  19. Mercury's thermal evolution and core crystallization regime

    Rivoldini, A.; Van Hoolst, T.; Dumberry, M.; Steinle-Neumann, G.

    2015-10-01

    Unlike the Earth, where the liquid core isentrope is shallower than the core liquidus, at the lower pressures inside Mercury's core the isentrope can be steeper than the melting temperature. As a consequence, upon cooling, the isentrope may first enter a solid stability field near the core mantle boundary and produce ironrich snow that sinks under gravity and produces buoyant upwellings of iron depleted fluid. Similar to bottom up crystallization, crystallization initiated near the top might generate sufficient buoyancy flux to drive magnetic field generation by compositional convection.In this study we model Mercury's thermal evolution by taking into account the formation of iron-rich snow to assess when the conditions for an internally magnetic field can be satisfied. We employ a thermodynamic consistent description of the iron high-pressure phase diagram and thermoelastic properties of iron alloys as well as the most recent data about the thermal conductivity of core materials. We use a 1-dimensional parametrized thermal evolution model in the stagnant lid regime for the mantle (e.g. [1]) that is coupled to the core. The model for the mantle takes into account the formation of the crust due to melting at depth. Mantle convection is driven by heat producing radioactive elements, heat loss from secular cooling and from the heat supplied by the core. The heat generated inside the core is mainly provided from secular cooling, from the latent heat released at iron freezing, and from gravitational energy resulting form the release of light elements at the inner core-outer core boundary as well as from the sinking of iron-rich snow and subsequent upwellings of light elements in the snow zone. If the heat flow out of the core is smaller than the heat transported along the core isentrope a thermal boundary will from at the top of the outer core. To determine the extension of the convecting region inside the liquid core we calculate the convective power [2]. Finally, we

  20. States agree on stronger physical protection regime

    Full text: Delegates from 89 countries agreed on 8 July to fundamental changes that will substantially strengthen the Convention on the Physical Protection of Nuclear Material (CPPNM). IAEA Director General Mohamed ElBaradei welcomed the agreement in saying 'This new and stronger treaty is an important step towards greater nuclear security by combating, preventing, and ultimately punishing those who would engage in nuclear theft, sabotage or even terrorism. It demonstrates that there is indeed a global commitment to remedy weaknesses in our nuclear security regime.' The amended CPPNM makes it legally binding for States Parties to protect nuclear facilities and material in peaceful domestic use, storage as well as transport. It will also provide for expanded cooperation between and among States regarding rapid measures to locate and recover stolen or smuggled nuclear material, mitigate any radiological consequences of sabotage, and prevent and combat related offences. The original CPPNM applied only to nuclear material in international transport. Conference President Dr. Alec Baer said 'All 89 delegations demonstrated real unity of purpose. They put aside some very genuine national concerns in favour of the global interest and the result is a much improved convention that is better suited to addressing the nuclear security challenges we currently face.' The new rules will come into effect once they have been ratified by two-thirds of the 112 States Parties of the Convention, expected to take several years. 'But concrete actions are already taking place around the world. For more than 3 years, the IAEA has been implementing a systematic Nuclear Security plan, including physical protection activities designed to prevent, detect and respond to malicious acts,' said Anita Nillson, Director of the IAEA's Office of Nuclear Security. The Agency's Nuclear Security Fund, set up after the events of 9/11, has delivered $19.5 million in practical assistance to 121 countries

  1. Human influence on California fire regimes.

    Syphard, Alexandra D; Radeloff, Volker C; Keeley, Jon E; Hawbaker, Todd J; Clayton, Murray K; Stewart, Susan I; Hammer, Roger B

    2007-07-01

    Periodic wildfire maintains the integrity and species composition of many ecosystems, including the mediterranean-climate shrublands of California. However, human activities alter natural fire regimes, which can lead to cascading ecological effects. Increased human ignitions at the wildland-urban interface (WUI) have recently gained attention, but fire activity and risk are typically estimated using only biophysical variables. Our goal was to determine how humans influence fire in California and to examine whether this influence was linear, by relating contemporary (2000) and historic (1960-2000) fire data to both human and biophysical variables. Data for the human variables included fine-resolution maps of the WUI produced using housing density and land cover data. Interface WUI, where development abuts wildland vegetation, was differentiated from intermix WUI, where development intermingles with wildland vegetation. Additional explanatory variables included distance to WUI, population density, road density, vegetation type, and ecoregion. All data were summarized at the county level and analyzed using bivariate and multiple regression methods. We found highly significant relationships between humans and fire on the contemporary landscape, and our models explained fire frequency (R2 = 0.72) better than area burned (R2 = 0.50). Population density, intermix WUI, and distance to WUI explained the most variability in fire frequency, suggesting that the spatial pattern of development may be an important variable to consider when estimating fire risk. We found nonlinear effects such that fire frequency and area burned were highest at intermediate levels of human activity, but declined beyond certain thresholds. Human activities also explained change in fire frequency and area burned (1960-2000), but our models had greater explanatory power during the years 1960-1980, when there was more dramatic change in fire frequency. Understanding wildfire as a function of the

  2. DEMOCRACIES HEIR OF AUTHORITARIAN REGIMES AS DEMOCRACIAS HERDEIRAS DE REGIMES AUTORITÁRIOS

    Edson Luis de Almeida Teles

    2008-04-01

    Full Text Available the objective of this article, making use of the theory of Hannah
    Arendt, is to show as the disruption with regimes of exception if it effected by means of transistions, of a vision of the politics as confrontation and violence for a model of the consensus and its counterpart was to occult the divergent ways with that the social subjetividades breach with the rational model, overshadowing the interpretations of the memory in the democratic normalizationo objetivo deste artigo, fazendo uso da teoria de Hannah Arendt,
    é mostrar como o rompimento com os regimes de exceção efetuou-se, por meio de transições, de uma visão da política como enfrentamento e violência, para um modelo do consenso, e sua contrapartida foi ocultar os modos divergentes com que as subjetividades sociais rompem com o modelo racional, obscurecendo as interpretações da memória na normalização democrática.

  3. Boundary between Stable and Unstable Regimes of Accretion. Ordered and Chaotic Unstable Regimes

    Blinova, A A; Lovelace, R V E

    2015-01-01

    We search for the boundary between stable and Rayleigh-Taylor unstable regimes of accretion to magnetized stars in a new set of high grid resolution simulations. We found that the boundary between stable and unstable regimes is mainly determined by the ratio of the corotation radius r_cor (where the Keplerian angular velocity in the disc matches the angular velocity of the star) to the magnetospheric radius r_m (where the magnetic stress in the magnetosphere matches the matter stress in the disc). Instability is stronger when r_cor is larger with respect to r_m, that is, when the gravitational force is larger than the centrifugal force at the inner disc. In the cases of a small tilt of the magnetosphere, Theta=5 deg, and a small alpha-parameter of viscosity, alpha=0.02, the boundary is located at r_cor approx. 1.4 r_m. Instability becomes stronger at higher values of viscosity, and occurs at lower values of r_cor/r_m. At higher values of Theta, the variability associated with instability decreases. Simulation...

  4. Modeling Non-robust Verification Regimes: Three Case Studies

    The term verification assumed a prominent role with the Chemical Weapons Convention (CWC) and the Comprehensive Nuclear Test Ban Treaty (CTBT) with the specification of verification regimes in the text of the treaty. In previous treaties, the term was either absent or, as in the case of the Non-Proliferation Treaty (NPT), mentioned in some broader context, such as, a State 'undertakes to accept safeguards, for the exclusive purpose of verification' Following the trend set by the CWC and the CTBT, extensive discussions have been taking place in the Committee on Disarmament for specifying a verification regime for the Biological Weapons Convention (BWC). These discussions have yet to produce any results, because it is becoming apparent that a robust verification system, if it could be specified, would be complex, intrusive and costly. With a heightened concern about proliferation of weapons of mass destruction, return to a regime without some monitoring, evaluation and assessment is very unlikely. Between these two extremes lies the concept of confidence building measures. The data collected using such a concept, whether by declarations, sensing, inspections, or some combination of these monitoring regimes, would lead to ambiguous conclusions about compliance. If one defines as robust a verification regime that provides a high level of confidence (in the vicinity of 100%) that all States Parties to a treaty are in compliance, then, the absence of any monitoring would reduce the confidence level to zero. The question then arises, what would be the level of confidence under a regime of confidence building measures. The question is equally relevant for the regime of safeguards under INFCIRC/540. One then would expect that the confidence of any State Party about compliance of others would range from very low to very high depending on the information collected by the monitoring system. There has been little, if any, effort to develop mechanisms for assessing

  5. An Examination of the Nature of Global MODIS Cloud Regimes

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji; Huffman, George J.

    2014-01-01

    We introduce global cloud regimes (previously also referred to as "weather states") derived from cloud retrievals that use measurements by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua and Terra satellites. The regimes are obtained by applying clustering analysis on joint histograms of retrieved cloud top pressure and cloud optical thickness. By employing a compositing approach on data sets from satellites and other sources, we examine regime structural and thermodynamical characteristics. We establish that the MODIS cloud regimes tend to form in distinct dynamical and thermodynamical environments and have diverse profiles of cloud fraction and water content. When compositing radiative fluxes from the Clouds and the Earth's Radiant Energy System instrument and surface precipitation from the Global Precipitation Climatology Project, we find that regimes with a radiative warming effect on the atmosphere also produce the largest implied latent heat. Taken as a whole, the results of the study corroborate the usefulness of the cloud regime concept, reaffirm the fundamental nature of the regimes as appropriate building blocks for cloud system classification, clarify their association with standard cloud types, and underscore their distinct radiative and hydrological signatures.

  6. Multifractal regime detecting method for financial time series

    Highlights: • A multifractal regime detecting method (MRDM) introduced based on generalized Hurst exponent. • Multifractal regimes in the KOSPI from 1990 through 2012 are identified. • Surrogated tests are performed for the validation of MRDM. - Abstract: We focus on time varying multifractality in time series and introduce a multifractal regime detecting method (MRDM) adopting a nonparametric statistical test for multifractality based on generalized Hurst exponent (GHE). MRDM is a practical method to discriminate multifractal regimes in a time series of any length using a moving time window approach with the adjustable time window size and the moving interval. MRDM is applied to simulations consisting of both multifractal and monofractal regimes, and the results confirm its validity. Using MRDM, we identify multifractal regimes in the time series of Korea composite stock price index (KOSPI) from 1990 through 2012 and observe the distinct stylized facts of the KOSPI return values in multifractal regimes such as the heavy tail distribution, high kurtosis, and the long memory in volatility. Surrogate tests based on improved amplitude adjusted Fourier transformation (IAAFT) algorithm, normal distribution, and generalized student t distribution are performed for the validation of MDRM, and the probable causes of multifractality in the KOSPI series are discussed

  7. Marine regime shifts: drivers and impacts on ecosystems services

    Rocha, J.; Yletyinen, J.; Biggs, R.; Blenckner, T.; Peterson, G.

    2015-01-01

    Marine ecosystems can experience regime shifts, in which they shift from being organized around one set of mutually reinforcing structures and processes to another. Anthropogenic global change has broadly increased a wide variety of processes that can drive regime shifts. To assess the vulnerability of marine ecosystems to such shifts and their potential consequences, we reviewed the scientific literature for 13 types of marine regime shifts and used networks to conduct an analysis of co-occurrence of drivers and ecosystem service impacts. We found that regime shifts are caused by multiple drivers and have multiple consequences that co-occur in a non-random pattern. Drivers related to food production, climate change and coastal development are the most common co-occurring causes of regime shifts, while cultural services, biodiversity and primary production are the most common cluster of ecosystem services affected. These clusters prioritize sets of drivers for management and highlight the need for coordinated actions across multiple drivers and scales to reduce the risk of marine regime shifts. Managerial strategies are likely to fail if they only address well-understood or data-rich variables, and international cooperation and polycentric institutions will be critical to implement and coordinate action across the scales at which different drivers operate. By better understanding these underlying patterns, we hope to inform the development of managerial strategies to reduce the risk of high-impact marine regime shifts, especially for areas of the world where data are not available or monitoring programmes are not in place.

  8. Shearing box simulations in the Rayleigh unstable regime

    Nauman, Farrukh

    2015-01-01

    We study the stability properties of Rayleigh unstable flows both in the purely hydrodynamic and magnetohydrodynamic (MHD) regimes for two different values of the shear $q=2.1, 4.2$ ($q = - d\\ln\\Omega / d\\ln r$) and compare it with the Keplerian case $q=1.5$. The Rayleigh stability criterion states that hydrodynamic shear flows are stable for $q2$ regime as the volume averaged velocities ($k=0$ mode) are unstable in this regime but the advantage of using a pseudospectral code is that the $k=0$ mode is conserved. We find that the $q>2$ regime is unstable to turbulence both in the hydrodynamic and in the MHD limit (with an initially weak magnetic field). In the $q>2$ regime, the velocity fluctuations dominate the magnetic fluctuations whereas in the $q2$ regime the instability produces primarily velocity fluctuations that cause magnetic fluctuations, with the causality reversed for the $q<2$ MRI unstable regime. We also find that the magnetic field correlation is increasingly localized as the shear is increa...

  9. The NPT regime: Progress and promises

    Full text: Thesis. The 'NPT regime' has arrived at a fateful crossroads. Though extended indefinitely in 1995, its future is my no means secure. The future 'progress' of this treaty will depend upon whether the 'promises' of its States parties are fully implemented and, eventually, upon the treaty's success in achieving fully universal membership. Challenges The treaty faces many short-term and longer-term challenges: Short term - The first Preparatory Committee meeting for the 2005 Review Conference will meet next year. NNWS will want to see some evidence of progress on nuclear disarmament (Art. VI), along the lines prescribed in the 13 'practical steps' agreed at the last Review Conference. Yet progress has been set back by: uncertainties over the future of the ABM Treaty; the failure of START II and the CTBT to enter into force; the lack of a FISMAT treaty and a treaty establishing a NWFZ in Central Asia; continued qualitative improvements in nuclear weapons; hints that nuclear testing may one day resume; the persistence of doctrines of first-use, pre-emptive use, and use against states that use CBW. Other compliance-related questions will arise over safeguards (e.g. the inability of the IAEA to conduct inspections in the DPRK; signs of a breakdown of the norm of full-scope IAEA safeguards, e.g. in South Asia). There are also concerns over the implementation of non-proliferation commitments (e.g. persisting allegations about nuclear weapon programmes in existing NNWS). The terrorist attacks in New York and Washington, D.C. on 11 September should also serve as a reminder of the new terrorist dangers relating to the possible use of weapons of mass destruction and unorthodox delivery systems. Longer term - Selectivity in the enforcement of NPT norms; unilateralism; IAEA funding uncertainties and shortfalls; difficulties in reaching universal membership (India, Pakistan, and Israel); continuing compliance problems with respect to both non-proliferation and

  10. Considerations on nonproliferation regime meeting in a changing world

    Kurihara, Hiroyoshi; Kikuchi, Masahiro [Nuclear Material Control Center, Tokyo (Japan)

    1994-12-31

    This paper summarizes the past history of worldwide nonproliferation regime, then proposes the future improvements on the regime. Present worldwide nonproliferation regime have been formulated during the cold war era. Therefore, the structure and measures of the regime were heavily influenced by the features of cold war era. Though the cold war was over, still new international order does not seem to be on the horizon, we need to review the present regime and to improve the regime compatible to new world situation. Generally speaking, the nonproliferation regime have gained moderate success so far. We could point out the following features as a kind of success: (1) No increase of overt Nuclear Weapon State (NWS), (2) All five NWSs have finally participated to the NPT, (3) South Africa has destroyed its nuclear weapons and became Non-Nuclear Weapon State (NNWS), (4) Successful conclusions of some regional arrangements, such as Tlatelolco, Ralotonga, and (5) Strengthening of export control on sensitive items. On the other hand, we recognize the following points as the failures of the regime. (6) India, Pakistan and Israel reject to join the NPT, (7) Existence of some violation against NPT regime, i.e. Iraqi case and DPRK case, (8) Insufficient effective measures against brain drain problem, (9) Risk exists for the long term extension of NPT, and (10) Insufficient flexibility to meet changing boundary conditions. We would propose the various measures for strengthening to meet changing boundary conditions, as follows: (11) Measures to be taken along with future civil use of Plutonium, (12) Strengthening and rationalizing international safeguards, (13) Countermeasures for emerging new types of nuclear proliferation, (14) Strengthening nuclear material control in NWS, (15) Measures to be taken for nuclear material from dismantled nuclear weapons, and (16) Nuclear disarmament. (author).

  11. Considerations on nonproliferation regime meeting in a changing world

    This paper summarizes the past history of worldwide nonproliferation regime, then proposes the future improvements on the regime. Present worldwide nonproliferation regime have been formulated during the cold war era. Therefore, the structure and measures of the regime were heavily influenced by the features of cold war era. Though the cold war was over, still new international order does not seem to be on the horizon, we need to review the present regime and to improve the regime compatible to new world situation. Generally speaking, the nonproliferation regime have gained moderate success so far. We could point out the following features as a kind of success: 1) No increase of overt Nuclear Weapon State (NWS), 2) All five NWSs have finally participated to the NPT, 3) South Africa has destroyed its nuclear weapons and became Non-Nuclear Weapon State (NNWS), 4) Successful conclusions of some regional arrangements, such as Tlatelolco, Ralotonga, and 5) Strengthening of export control on sensitive items. On the other hand, we recognize the following points as the failures of the regime. 6) India, Pakistan and Israel reject to join the NPT, 7) Existence of some violation against NPT regime, i.e. Iraqi case and DPRK case, 8) Insufficient effective measures against brain drain problem, 9) Risk exists for the long term extension of NPT, and 10) Insufficient flexibility to meet changing boundary conditions. We would propose the various measures for strengthening to meet changing boundary conditions, as follows: 11) Measures to be taken along with future civil use of Plutonium, 12) Strengthening and rationalizing international safeguards, 13) Countermeasures for emerging new types of nuclear proliferation, 14) Strengthening nuclear material control in NWS, 15) Measures to be taken for nuclear material from dismantled nuclear weapons, and 16) Nuclear disarmament. (author)

  12. Raman amplification in the broken-wave regime

    Farmer, John P

    2015-01-01

    In regimes far beyond the wavebreaking theshold of Raman amplification, we show that significant amplifcation can occur after the onset of wavebreaking, before phase mixing destroys the coupling between pump and probe. The amplification efficiency in this regime is therefore strongly dependent on the energy-transfer rate when wavebreaking occurs, and is, as such, sensitive to both the probe amplitude and profile. In order to access the higher-efficiency broken-wave regime, a short, intense probe is required. Parameter scans show the marked difference in behaviour compared to below wavebreaking, where longer, more energetic pulses lead to improved efficiencies.

  13. Diversity-Multiplexing Tradeoff in the Low-SNR Regime

    Loyka, Sergey

    2011-01-01

    An extension of the popular diversity-multiplexing tradeoff framework to the low-SNR (or wideband) regime is proposed. The concept of diversity gain is shown to be redundant in this regime since the outage probability is SNR-independent and depends on the multiplexing gain and the channel power gain statistics only. The outage probability under the DMT framework is obtained in an explicit, closed form for a broad class of channels. The low and high-SNR regime boundaries are explicitly determined for the scalar Rayleigh-fading channel, indicating a significant limitation of the SNR-asymptotic DMT when the multiplexing gain is small.

  14. Formations and transformations of language regimes: Turkey, a case study

    Balçık, Mehmet Berk; Balcik, Mehmet Berk

    2009-01-01

    There are two main aims of this dissertation: to present a legal and ideological history of the formation of the language regime in Turkey in the Republican period; and to analyze its transformation in the post-1980 era. A language regime is defined in this dissertation as a de jure or de facto regulation of the linguistic behavior, in its content or in its status, within a space of communicative action, such as that of a nation-state or a speech group. In other words, a language regime is a ...

  15. Laserlike and atomlike regimes in a one-atom laser

    Boozer, A. D.

    2008-01-01

    We consider a three-level model of a one-atom laser, and show that there are two limiting regimes of parameter space, one in which the system behaves like a conventional laser and one in which the system exhibits novel quantum properties. We show that in the first limiting regime, the model can be approximated by semiclassical laser theory, and in the second limiting regime the model can be approximated as an effective two-level atom. We also perform numerical simulations that confirm the lim...

  16. Tidal regimes and salt marshes - the River Hamble analogue

    Construction of estuarine tidal-energy barrages has a potentially major effect on the tidal regime of the estuary, particularly upstream of a barrage. Because tidal regime largely controls the distribution and species composition of intertidal plant and animal communities, it is important to understand how barrages may affect such communities. The main objectives of the research described in this report were to relate recent changes in tidal regime within an embanked area of salt marsh and mudflat to changes in the distribution of plant species. This was to test predictions about tidal control of species' range and to assess the site's suitability as an analogue of post-barrage conditions. (author)

  17. Nonlinear Regime of a Single-mode CSR Instability

    Close to the shielding threshold of synchrotron radiation in a toroidal waveguide the coherent synchrotron radiation (CSR) instability may be driven by a single synchronous mode. The linear analysis of the problem is presented elsewhere. In this paper we study a nonlinear regime of the single-mode CSR instability. We show that in the nonlinear regime the instability is described by a system of equations which, after a proper scaling, coincides with the 1D FEL instability theory. We present numeric and analytic analysis of the non-linear regime for the time interval large compared with the damping time taking into account radiation damping and diffusion due to the quantum fluctuations

  18. Information management in NACD regimes: a comparative analysis

    While all non-proliferation, arms control and disarmament (NACD) regimes must address the issue of information management, this area has remained an under-explored part of the arms control field. This paper compares information management processes across a variety of NACD regimes for the purpose of identifying potential synergies between regimes and suggesting means by which to strengthen future arms control verification efforts. The paper explores the information management systems of the International Atomic Energy Agency (IAEA), the United Nations Special Commission in Iraq (UNSCOM), the Conventional Forces in Europe Agreement (CFE), and the Comprehensive Test Ban Treaty (CTBT). (author)

  19. Raman amplification in the coherent wave-breaking regime.

    Farmer, J P; Pukhov, A

    2015-12-01

    In regimes far beyond the wave-breaking threshold of Raman amplification, we show that significant amplification can occur after the onset of wave breaking, before phase mixing destroys the coherent coupling between pump, probe, and plasma wave. Amplification in this regime is therefore a transient effect, with the higher-efficiency "coherent wave-breaking" (CWB) regime accessed by using a short, intense probe. Parameter scans illustrate the marked difference in behavior between below wave breaking, in which the energy-transfer efficiency is high but total energy transfer is low, wave breaking, in which efficiency is low, and CWB, in which moderate efficiencies allow the highest total energy transfer. PMID:26764840

  20. Regime-Switching Risk: To Price or Not to Price?

    Tak Kuen Siu

    2011-01-01

    “normative” issues to be addressed in pricing contingent claims under a Markovian, regime-switching, Black-Scholes-Merton model. We address this issue using a minimal relative entropy approach. Firstly, we apply a martingale representation for a double martingale to characterize the canonical space of equivalent martingale measures which may be viewed as the largest space of equivalent martingale measures to incorporate both the diffusion risk and the regime-switching risk. Then we show that an optimal equivalent martingale measure over the canonical space selected by minimizing the relative entropy between an equivalent martingale measure and the real-world probability measure does not price the regime-switching risk. The optimal measure also justifies the use of the Esscher transform for option valuation in the regime-switching market.

  1. Optimization of Normal Regimes of Power Transmission Lines

    E. G. Pospelov

    2014-06-01

    Full Text Available In order to optimize normal regimes of the power transmission lines notions of economic, maximum and the largest efficiency of a transmission line are used. Power losses by wire corona transmission losses are considered.

  2. Optimization of Normal Regimes of Power Transmission Lines

    E. G. Pospelov; Pospelov, G. E.(Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany)

    2014-01-01

    In order to optimize normal regimes of the power transmission lines notions of economic, maximum and the largest efficiency of a transmission line are used. Power losses by wire corona transmission losses are considered.

  3. Stochastic regimes in very-low-frequency fluidic oscillator

    Tesař, Václav

    2016-03-01

    Paper discusses interesting unexpected stochastic regimes discovered in a fluidic oscillator designed for operation at very low oscillation frequencies - without the inconvenience of the long feedback loops needed in standard low-frequency oscillator designs. The new oscillator contains a pair of bistable turn-down active valves operating in anti-parallel — essentially analogous to Abraham & Bloch electric "multibrateur" invented in 1919. Three different self-excited oscillation regimes were found. In the order of increasing supplied flow rate, these regimes are characterised by: (A) generation of stochastic-duration multi-pulse packs, (B) generation of individual pulses with a degree of periodicity, and (C) regime with randomly appearing flow pulses separated by intervals of the order of seconds.

  4. Determination of three characteristic regimes of weakly charged polyelectrolytes monolayers

    We have demonstrated that monolayer films of randomly charged polystyrene sulfonated acid (PSSA) can be produced by the Langmuir technique, and observed the micro-domain structures, produced by the phase separation of electrostatically charged moieties and the hydrophobic moieties. Using atomic force microscopy and Langmuir isotherm, we found three specific regimes for the polyelectrolytes with various degrees of sulfonation (4-35%); very low charged PSSA (4-5%) in the hydrophobic regime, moderately charged PSSA (6-16%) which possessed a well-balanced nature between electrostatic and the hydrophobic interactions, and strongly amphiphilic nature of PSSA (6-16%) in the ionomer regime. Finally, we could categorize PSSA 35% in the polyelectrolyte regime, due to the dominance of the electrostatic interactions over the hydrophobic interactions

  5. Nonequilibrium electron transport through quantum dots in the Kondo regime

    Wölfle, Peter; Paaske, Jens; Rosch, Achim; Kroha, Johann

    2005-01-01

    Electron transport at large bias voltage through quantum dots in the Kondo regime is described within the perturbative renormalization group extended to nonequilibrium. The conductance, local magnetization, dynamical spin susceptibility and local spectral function are calculated. We show how the ...

  6. The Hadley and Rossby regimes in a spherical atmosphere

    Feldstein, S. B.; Clark, J. H. E.

    1985-01-01

    The properties of the steady Hadley and Rossby regimes for a thermally forced rotating fluid on a sphere are studied. The two layer modified geostrophic model is employed which allows for thermal advection by the divergent wind and time dependent static stability. Heating processes are parameterized using the Newtonian approximation and Rayleigh friction is accounted for. The equations are transformed to spectral form using spherical harmonics and then truncated retaining a simple axisymmetric state and initial, one wave. A time independent Hadley circulation is obtained which is neutral to axisymmetric disturbances but unstable to wave like perturbations for intermediate values of the meridional temperature gradient, indicating the existence of both an upper and lower symmetric Hadley regime. An analytical solution for the steady Rossby circulation is determined for values of the meridional temperature gradient where the Hadley regime is unstable. Linear perturbation theory is used to show that within the steady Rossby regime two or more waves cannot exist simultaneously.

  7. Evolving International Trade and Monetary Regimes and Related Policy Issues

    Kumiharu Shigehara

    1991-01-01

    This essay focuses on some aspects of policy issues relating to evolving international trade and monetary regimes, and patterns of national saving and investment balances conducive to better global economic performance.

  8. Spacetime-noncommutativity regime of Loop Quantum Gravity

    Amelino-Camelia, Giovanni; Ronco, Michele; Cesarini, Lorenzo; Lecian, Orchidea Maria

    2016-01-01

    A recent study by Bojowald and Paily provided a path toward the identification of an effective quantum-spacetime picture of Loop Quantum Gravity, applicable in the "Minkowski regime", the regime where the large-scale (coarse-grained) spacetime metric is flat. A pivotal role in the analysis is played by Loop-Quantum-Gravity-based modifications to the hypersurface deformation algebra, which leave a trace in the Minkowski regime. We here show that the symmetry-algebra results reported by Bojowald and Paily are consistent with a description of spacetime in the Minkowski regime given in terms of the $\\kappa$-Minkowski noncommutative spacetime, whose relevance for the study of the quantum-gravity problem had already been proposed for independent reasons.

  9. Capillary Breakup of a Liquid Bridge: Identifying Regimes and Transitions

    Li, Yuan

    2016-01-01

    Computations of the breakup of a liquid bridge are used to establish the limits of applicability of similarity solutions derived for different breakup regimes. These regimes are based on particular viscous-inertial balances, that is different limits of the Ohnesorge number $Oh$. To accurately establish the transitions between regimes, the minimum bridge radius is resolved through four orders of magnitude using a purpose-built multiscale finite element method. This allows us to construct a quantitative phase diagram for the breakup phenomenon which includes the appearance of a recently discovered low-$Oh$ viscous regime. The method used to quantify the accuracy of the similarity solutions allows us to identify a number of previously unobserved features of the breakup, most notably an oscillatory convergence towards the viscous-inertial similarity solution. Finally, we discuss how the new findings open up a number of challenges for both theoretical and experimental analysis.

  10. Quantifying flooding regime in floodplain forests to guide river restoration

    Christian O. Marks; Keith H Nislow; Magilligan, Francis J.

    2014-01-01

    Abstract Determining the flooding regime needed to support distinctive floodplain forests is essential for effective river conservation under the ubiquitous human alteration of river flows characteristic of the Anthropocene Era. At over 100 sites throughout the Connecticut River basin, the largest river system in New England, we characterized species composition, valley and channel morphology, and hydrologic regime to define conditions promoting distinct floodplain forest assemblages. Species...

  11. Laboratory experiment on boundaries of upper stage plane bed regime

    Zrostlík, Štěpán; Matoušek, Václav

    2016-04-01

    Results are discussed of laboratory experiments on criteria determining the transition between the regime of dunes and the upper stage plane bed (UPB) regime and the transition between the UPB regime and the regime of wavy flow. The experiments were carried for 3 fractions of plastic material and two fractions of glass beads in a broad range of flow conditions (different discharges of water and solids and longitudinal bed slopes) in a tilting flume. The experiments reveal that, contrary to expectations, a constant value of the Shields parameter is not an appropriate criterion for the transition between the dune regime and the UPB regime. Furthermore, the transition appears to be insensitive to the total discharge of solids and water. Instead, the criterion seems to be well represented by a constant value of the average transport concentration of sediment (the ratio of volumetric discharge of solids and volumetric discharge of mixture). The experimental results exhibit a very tight correlation between the transport concentration and the longitudinal bed slope. Hence, a constant value of the bed slope can be considered an appropriate criterion for the transition. The transition between the UPB regime and the wavy regime (significant waves develop but they are not always standing waves) is found at a constant value of Froude number, which is in agreement with literature, although it is found at a higher value than the literature usually suggests (Fr = 1.2 instead of 1.0). Hence, the transition occurs in the super-critical flow but it is not necessarily associated with the critical flow.

  12. Brownian colloids in underdamped and overdamped regimes with nonhomogeneous temperature

    Sancho, J. M.

    2015-12-01

    The motion of Brownian particles when temperature is spatially dependent is studied by stochastic simulations and theoretical analysis. Nonequilibrium steady probability distributions Ps t(z ,v ) for both underdamped and overdamped regimes are analyzed. The existence of local kinetic energy equipartition theorem is also discussed. The transition between both regimes is characterized by a dimensionless friction parameter. This study is applied to three physical systems of colloidal particles.

  13. Patent regimes, firms and the commodification of knowledge

    Benjamin Coriat; Olivier Weinstein

    2011-01-01

    This paper analyses the evolution of the intellectual property regime (IPR), and more precisely the patent regime, in the USA since the 19-th century. To do so, we consider intellectual property laws within the context of wider changes in capitalism, focusing on two main historical phases: firstly, the period covering the formation and development of 'corporate capitalism' dominated by large corporations and then the new phase, which opened up in the 1980s, marked by the rise to power of fina...

  14. Capital Controls and the Timing of Exchange Regime Collapse

    Daekuen Park; Jeffrey Sachs

    1987-01-01

    This paper investigates the nature of balance of payments crises in regimes with capital controls. It extends earlier work on capital controls by assuming that households manage their consumption and asset portfolios to maximize intertemporal utility. Our main result is that capital controls are effective in delaying, but not preventing, a breakdown of a fixed exchange rate regime in the presence of money-financed fiscal deficits.

  15. Constructing a Transnational Timber Legality Assurance Regime: Architecture, Accomplishments, Challenges

    Overdevest, C.; Zeitlin, J

    2013-01-01

    The emerging transnational timber legality assurance regime comprises a set of interrelated policy instruments, both public and private, aimed at controlling trade in illegally logged wood and wood products. The potentially productive interactions among these instruments in the emerging forestry regime create prospects for engendering learning, stimulating cross-fertilization, and enhancing accountability. In this article, we analyze the EU's Forest Law Enforcement Governance and Trade (FLEGT...

  16. The Limited Viability of Dual Exchange-Rate Regimes

    Jacob A. Frenkel; Assaf Razin

    1986-01-01

    This paper examines the viability of dual exchange-rate regimes. Typically, under such a regime the exchange rates applicable to current-account(commercial) transactions and to capital-account (financial) transactions differ from each other. This difference may be determined in the free market if the authorities peg the commercial exchange rate and set a binding quota on external borrowing, or it may result from direct pegging of both exchange rates. The analysis starts with a specification o...

  17. A Private Property Rights Regime to Replenish a Groundwater Aquifer

    Bill Provencher

    1993-01-01

    Groundwater management is often reactive, and in some cases the groundwater stock (groundwater table) of an aquifer may fall below its optimal steady-state level before any thought is given to management. This paper examines a private property rights regime to restore a groundwater resource to its optimal steady-state. Results from a stochastic dynamic programming model of Madera County, California show that the private property rights regime recovers about 95 percent of the potential gain fr...

  18. Real Output and Prices Adjustments under Different Exchange Rate Regimes

    Rajmund MIRDALA

    2013-01-01

    Exchange rate regimes evolution in the European transition economies refers to one of the most crucial policy decision in the beginning of the 1990s employed during the initial stages of the transition process. During the period of last two decades we may identify some crucial milestones in the exchange rate regimes evolution in the European transition economies. due to existing diversity in exchange rate arrangements in the European transition economies in the pre-ERM2 period there seems to ...

  19. Shock-Induced Flows through Packed Beds: Transient Regimes

    Shtemler, Yuri M; Britan, Alex

    2006-01-01

    The early stage of the transient regimes in the shock-induced flows within solid-packed beds are investigated in the linear longwave and high-frequency approximation. The transient resistance law is refined as the Duhameltime integral that follows from the general concept of dynamic tortuosity and compressibility of the packed beds. A closed-form solution is expected to describe accurately the early stage of the transient regime flow and is in qualitative agreement with available experimental data.

  20. Generating Schemes for Long Memory Processes: Regimes, Aggregation and Linearity

    Davidson, James; Sibbertsen, Philipp

    2002-01-01

    This paper analyses a class of nonlinear time series models exhibiting long memory. These processes exhibit short memory fluctuations around a local mean (regime) which switches randomly such that the durations of the regimes follow a power law. We show that if a large number of independent copies of such a process are aggregated, the resulting processes are Gaussian, have a linear representation, and converge after normalisation to fractional Brownian motion. Two cases arise, a stationary ca...

  1. Were there regime switches in U.S. monetary policy?

    Christopher A. Sims; Zha, Tao

    2004-01-01

    A multivariate model, identifying monetary policy and allowing for simultaneity and regime switching in coefficients and variances, is confronted with U.S. data since 1959. The best fit is with a model that allows time variation in structural disturbance variances only. Among models that also allow for changes in equation coefficients, the best fit is for a model that allows coefficients to change only in the monetary policy rule. That model allows switching among three main regimes and one r...

  2. The market manipulation regime in the European Union

    Li, Xue

    2015-01-01

    Market manipulation is an illegal practice that enables a person can profit from practices that artificially raise or lower the prices of an instrument in the financial markets. Its prohibition is based on the 2003 Market Abuse Directive in the EU. The current market manipulation regime was broadly considered as a big success except for enforcement and supervisory inconsistencies in the Member States at the initial. A review of the market manipulation regime began at the end of 2007, which...

  3. PARTICULARITIES OF PARLIAMENTARY OVERSIGHT IN DIFFERENT POLITICAL REGIMES

    Silvia-Claudia CĂLIN-MIHALCEA

    2015-01-01

    The quality and intensity of the parliamentary oversight performed over the Government are shaped by several major criteria: political regime, electoral system, structure of the Parliament (unicameral/bicameral), parliamentary culture and tradition. This paper emphasizes some distinctive elements and particular mechanisms of the control exercised over the activities of the executive power, from the point of view of the political regime established in states with modern democracies.

  4. A critical review of the Chilean civil nuclear liability regime

    This article reviews the Chilean civil nuclear liability regime. The Nuclear Security Act (Law 18.302), enacted in 1984, and the Vienna Convention on Civil Liability for Nuclear Damage, ratified ed by Chile in 1989, are the fundamental laws of the current regime. Although Chile has no nuclear power plants, it is still important to analyze how the Chilean legislation would protect citizens from nuclear damages. This paper does not consider the policy reasons for and against the promotion of atomic energy. Rather, it critically examines the current status of the Chilean nuclear regime. Undoubtedly, if in the future Chile chooses to include nuclear sources in its energy mix, it will not be enough to introduce some isolated legal amendments, but it will be necessary to build a new Chilean Energy Regime which includes nuclear energy. In that scenario, though, it will be useful to know and understand how the current nuclear liability regime works. From this point of view, the reforms this article proposes to the current nuclear liability regime might be helpful to academics and policy makers alike

  5. Development of Risk Assessment Methodology for State's Nuclear Security Regime

    Threats of nuclear terrorism are increasing after 9/11 terrorist attack. Treats include nuclear explosive device (NED) made by terrorist groups, radiological damage caused by a sabotage aiming nuclear facilities, and radiological dispersion device (RDD), which is also called 'dirty bomb'. In 9/11, Al Qaeda planed to cause radiological consequences by the crash of a nuclear power plant and the captured airplane. The evidence of a dirty bomb experiment was found in Afganistan by the UK intelligence agency. Thus, the international communities including the IAEA work substantial efforts. The leaders of 47 nations attended the 2010 nuclear security summit hosted by President Obama, while the next global nuclear summit will be held in Seoul, 2012. Most states established and are maintaining state's nuclear security regime because of the increasing threat and the international obligations. However, each state's nuclear security regime is different and depends on the state's environment. The methodology for the assessment of state's nuclear security regime is necessary to design and implement an efficient nuclear security regime, and to figure out weak points. The IAEA's INPRO project suggests a checklist method for State's nuclear security regime. The IAEA is now researching more quantitative methods cooperatively with several countries including Korea. In this abstract, methodologies to evaluate state's nuclear security regime by risk assessment are addressed

  6. International regime formation: Ozone depletion and global climate change

    Two theoretical perspectives, neorealism and neoliberal institutionalism, dominate in international relations. An assessment is made of whether these perspectives provide compelling explanations of why a regime with specific targets and timetables was formed for ozone depletion, while a regime with such specificity was not formed for global climate change. In so doing, the assumptions underlying neorealism and neoliberal institutionalism are examined. A preliminary assessment is offered of the policymaking and institutional bargaining process. Patterns of interstate behavior are evolving toward broader forms of cooperation, at least with regard to global environmental issues, although this process is both slow and cautious. State coalitions on specific issues are not yet powerful enough to create a strong community of states in which states are willing to devolve power to international institutions. It is shown that regime analysis is a useful analytic framework, but it should not be mistaken for theory. Regime analysis provides an organizational framework offering a set of questions regarding the principles and norms that govern cooperation and conflict in an issue area, and whether forces independent of states exist which affect the scope of state behavior. An examination of both neorealism and neoliberal institutionalism, embodied by four approaches to regime formation, demonstrates that neither has sufficient scope to account for contextual dynamics in either the ozone depletion or global climate change regime formation processes. 261 refs

  7. Direct numerical simulations of the dense regime of roughness

    MacDonald, Michael; Chan, Leon; Chung, Daniel; Hutchins, Nicholas; Ooi, Andrew

    2015-11-01

    We investigate the sparse and dense regimes of roughness using Direct Numerical Simulations (DNS) of turbulent flow over three-dimensional sinusoidal surfaces in the transitionally rough regime. The sparse regime is known to lead to an increase in the Hama roughness function, ΔU+ , as the roughness density increases, while the dense regime is associated with a decrease in ΔU+ as density increases. In this parametric study, the wavelength of the sinusoidal roughness elements is varied while the roughness height is fixed. The minimal-span channel is used, as the high cost of the grid would otherwise make the dense roughness simulations unattainable. It was found that the dense regime began at solidity values (frontal area divided by wall-parallel projected area) greater than 0.15, in agreement with the literature. An analysis of the mean momentum balance above the roughness reveals that the decrease in ΔU+ in the dense regime is due to a reduction in the Reynolds shear stress. This reduction is located just above the roughness crest in the near-wall region, and the difference in the energy spectra of streamwise velocity between smooth and dense roughness clearly demonstrates that this is at long streamwise length scales.

  8. Do family policy regimes matter for children's well-being?

    Engster, Daniel; Stensöta, Helena Olofsdotter

    2011-01-01

    Researchers have studied the impact of different welfare state regimes, and particularly family policy regimes, on gender equality. Very little research has been conducted, however, on the association between different family policy regimes and children's well-being. This article explores how the different family policy regimes of twenty OECD countries relate to children's well-being in the areas of child poverty, child mortality, and educational attainment and achievement. We focus specifically on three family policies: family cash and tax benefits, paid parenting leaves, and public child care support. Using panel data for the years 1995, 2000, and 2005, we test the association between these policies and child well-being while holding constant for a number of structural and policy variables. Our analysis shows that the dual-earner regimes, combining high levels of support for paid parenting leaves and public child care, are strongly associated with low levels of child poverty and child mortality. We find little long-term effect of family policies on educational achievement, but a significant positive correlation between high family policy support and higher educational attainment. We conclude that family policies have a significant impact on improving children's well-being, and that dual-earner regimes represent the best practice for promoting children's health and development. PMID:21692245

  9. Trends in the hydrologic regime of Alpine rivers

    Bard, Antoine; Renard, Benjamin; Lang, Michel; Giuntoli, Ignazio; Korck, Jane; Koboltschnig, Gernot; Janža, Mitja; d'Amico, Michele; Volken, David

    2015-10-01

    This paper describes a trend analysis performed on 177 streamflow time series collected over the Alps in Central Europe. The analysis covers several facets of the Alpine hydrologic regimes, including winter droughts and spring snowmelt flows, both in terms of severity and timing of occurrence. Statistical trend tests are applied at a local scale (i.e. on a site-by-site basis) and at a regional scale (seeking a common trend for sites within the same hydro-climatic region). The overall results indicate a trend toward less severe winter droughts, and consistent changes in the timing of snowmelt flows. However, a more in-depth analysis at the scale of hydro-climatic regimes reveals more contrasted changes. While most glacial- and snowmelt-dominated regimes show a decreasing trend in the severity of winter droughts, contrasted trends are found for mixed snowmelt-rainfall regimes in the Southeastern Alps. Changes in the timing of snowmelt flows (earlier start and increased duration of the snowmelt season) mostly affect glacial- and snowmelt-dominated regimes. Lastly, glacial regimes show an increase in the volume and the peak of snowmelt flows.

  10. Sensitivity of streamflows to hydroclimatic fluctuations: resilience and regime shifts

    Botter, Gianluca; Basso, Stefano; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2016-04-01

    Landscape and climate alterations foreshadow global-scale shifts of river flow regimes. However, a theory that identifies the range of foreseen impacts on streamflows resulting from inhomogeneous forcings and sensitivity gradients across diverse regimes is lacking. In this contribution, we use a dimensionless index embedding simple climate and landscape attributes (the ratio of the mean interarrival of streamflow-producing rainfall events and the mean catchment response time) to discriminate erratic regimes with enhanced intra-seasonal streamflow variability from persistent regimes endowed with regular flow patterns. The proposed classification is successfully applied to 110 seasonal streamflow distributions observed in 44 catchments of the Alps and the United States, allowing the identification of emerging patterns in space and time. In the same framework, the impact of multi-scale fluctuations of the underlying climatic drivers (temperature, precipitation) on the streamflow distributions can be analyzed. Theoretical and empirical data show that erratic regimes, typical of rivers with low mean discharges, are highly resilient in that they hold a reduced sensitivity to variations in the external forcing. Specific temporal trajectories of streamflow distributions and flow regime shifts driven by land-cover change and rainfall patterns can be also evidenced. The approach developed offers an objective basis for the analysis and prediction of the impact of climate/landscape change on water resources.

  11. Consumption, investment and life insurance under different tax regimes

    Bruun, Kenneth

    2013-01-01

    We study the effects of introducing taxation in classical continuous-time optimization problems with utility from consumption, bequest and retirement savings. Inspired by actual tax favoured retirement savings programs, we formulate and solve the optimization problem for various tax regimes, and ...... analysis of the results based on realistic parameter values and regimes. Based on American and Danish tax regimes we estimate the values of existing retirement saving favouring to be 1 – 2 percent of lifetime income.......We study the effects of introducing taxation in classical continuous-time optimization problems with utility from consumption, bequest and retirement savings. Inspired by actual tax favoured retirement savings programs, we formulate and solve the optimization problem for various tax regimes, and...... compare tax effects on consumption/savings contributions, investment and purchase of life insurance under the regimes. The optimization problems have analytical solutions, which allow for easy comparison of tax effects under the different regimes. To substantiate the results we also present a numerical...

  12. Numerical simulation of transitions between back discharge regimes

    Jánský, Jaroslav; Bessières, Delphine; Paillol, Jean; Lemont, Florent

    2014-11-01

    This paper presents numerical simulations of transitions between back discharge regimes. Back discharge refers to any discharge initiated at or near a dielectric layer covering a passive electrode. In this work, a pinhole in a dielectric layer on a plane anode serves as a model for back discharge activity. We have studied transitions between back discharge regimes by varying the surface charge density on the dielectric layer and the electric field in front of the pinhole. From the variation of these two independent parameters, the back discharge regimes have been depicted as a mode diagram inspired by the experimental study of Masuda and Mizuno. The resulting diagram includes the different discharge regimes that are commonly observed in experiments. The propagation of a positive ionizing wave inside the pinhole toward its edge, and the resulting formation of a plasma zone at its exit constitute the onset stage of back discharge. From this stage, the transitions to volume discharge or surface discharge can occur. The volume discharge regime consists of the propagation of a discharge in space toward the cathode which can be superimposed with the propagation of a discharge above the dielectric layer surface. The diagram reveals the conditions for transitions between back discharge regimes.

  13. EXCHANGE RATE REGIMES AND FISCAL PERFORMANCE. DO FIXED EXCHANGE RATE REGIMES GENERATE MORE DISCIPLINE THAN FLEXIBLE ONES?

    Guillermo J. Vuletin

    2004-01-01

    This paper analyzes the influence of exchange rate regimes on fiscal performance, focusing on the difference between fixed and flexible exchange rates. For these ends, a sample of 83 countries for the 1974-1998 period, the GMM methodology for dynamic proposal panel models proposed by Arellano and Bond (1991) and diverse exchange rate classifications are used. In relation to the latter, this paper discusses recent regime classifications and proposes a new exchange rate classification that perm...

  14. Exchange Rate Regimes – A periodical overview and a critical analysis of exchange rate regimes in Kosovo

    Flamur Bunjaku

    2015-01-01

    Exchange rate regimes and the monetary policy are the key instruments governments use to achieve their economic and financial objectives. Moreover, due to global financial crisis the latter instruments get more importance. Empirical evidences show that exchange rate regimes in Kosovo and its monetary policy throughout their development were mainly influenced by different political and historical developments. In regard of Euroisation of monetary system in Kosovo it was found that this action ...

  15. Regime maintenance in post-Soviet Kazakhstan: the case of the regime and oil industry relationship (1991-2005)

    Ostrowski, Wojciech

    2008-01-01

    The main aim of this thesis is to investigate the ways in which the authoritarian regime in post-Soviet Kazakhstan maintained itself in power from 1991 until 2005. This study endeavours to uncover the palette of the regime’s methods by analysing the ways in which it went about controlling the oil industry – an industry with which the political and economical future of Kazakhstan is inseparably intertwined. The empirical section of this study investigates the interplay between the regime and...

  16. Contribution to the study of {sup 233}U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/{sup 233}U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code; Contribution a l'etude de la production d'{sup 233}U en combustible MOX-ThPu en reacteur a eau sous pression. Scenarios de transition vers des concepts isogenerateurs Th/{sup 233}U en spectre thermique. Developpement du code MURE d'evolution du combustible

    Michel-Sendis, F

    2006-12-15

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  17. History of Uranium-233(233U)Processing at the Rocky Flats Plant. In support of the RFETS Acceptable Knowledge Program

    This report documents the processing of Uranium-233 at the Rocky Flats Plant (Rocky Flats Environmental Technology Site). The information may be used to meet Waste Isolation Pilot Plant (WIPP) Waste Acceptance Criteria (WAC)and for determining potential Uranium-233 content in applicable residue waste streams

  18. Recent Experiments on the Beta Activity of Fission Products from the Thermal-Neutron Fission of U233, U235 and Pu239

    The build-up of beta-activity of fission products from the low-energy fission of U233 and U235 has been measured as a function of the lime t after starting the irradiation of the fissionable material with thermal neutrons. By differentiating the beta-activity divided by the constant fission product rate one obtains the mean beta-decay rate β(t) per fission as a function of the time t after fission. The uranium targets were mounted within a 4π proportional counter, coincident conversion electrons and γ-rays being thereby eliminated. The background of fast neutrons and γ-rays was strongly reduced by using a neutron beam tube with a liquid nitrogen-cooled bismuth single crystal filter. The fission product rate was measured with the same counter. The measurements cover the time interval from 0.01 s to 10 h. The results are compared with other experimental data and existing theories. The total number of beta-decays per fission was found to be 5.25 ± 0.2 and 5.93 ± 0.2 for U233 and U235 respectively compared with theoretical values of 5.27 and 6.10 respectively. (author)

  19. Radiochemical method for the simultaneous determination of 233U, 236U, 237Np, 236Pu, 238Pu, and 239Pu in biological materials

    A radiochemical method has been developed for the determination of multiple isotopes of uranium, neptunium, and plutonium in biological materials. The elements are separated from the other sample constituents and from each other by anion exchange in halide media. Their recoveries are monitored by isotopic diluents. The amounts of the analyte and diluent isotopes of each element are measured alpha spectrometrically. The interelemental separation factors are generally greater than 102, and the recovery of each element ranges from 60% to 90%. 4 references, 1 table

  20. Positron acceleration in doughnut wakefields in the blowout regime

    Vieira, Jorge; Mendonca, Jose; Fonseca, Ricardo; Silva, Luis

    2014-10-01

    Most important plasma acceleration results were reached in the so called bubble or blowout regime. Although ideally suited for electron acceleration, it has been recognized that non-linear regimes are not adequate to accelerate positrons. New configurations enabling positron acceleration in non-linear regimes would therefore open new research paths for future plasma based collider configurations. In this work, we explore, analytically and through 3D OSIRIS simulations, a novel configuration for positron acceleration in strongly non-linear laser wakefield excitation regimes using Laguerre-Gaussian laser drivers to drive doughnut shaped wakefields with positron focusing and accelerating fields. We demonstrate that positron focusing-fields can be up to an order of magnitude larger than electron focusing in the spherical blowout regime. The amplitude of the accelerating fields is similar to the spherical blowout. Simulations demonstrate laser self-guiding and stable positron acceleration until the laser energy has been exhausted to the plasma. Other realisations of the scheme, using two Gaussian laser pulses, will also be explored. FCT Grant No EXPL/FIS-PLA/0834/2012 and European Research Council ERC-2010-AdG Grant No. 267841.

  1. THE IMPACT OF THE GLOBAL NUCLEAR SAFETY REGIME IN BRAZIL

    A turning point of the world nuclear industry with respect to safety occurred due to the accident at Chernobyl, in 1986. A side from the tragic personal losses and the enormous financial damage, the Chernobyl accident has literally demonstrated that ''a nuclear accident anywhere is an accident everywhere''. The impact was felt immediately by the nuclear industry, with plant cancellations (e.g. Austria), elimination of national programs (e.g. Italy) and general construction delays. However, the reaction of the nuclear industry was equally immediate, which led to the proposal and establishment of a Global Nuclear Safety Regime. This regime is composed of biding international safety conventions, globally accepted safety standard, and a voluntary peer review system. In a previous work, the author has presented in detail the components of this Regime, and briefly discussed its impact in the Brazilian nuclear power organizations, including the Regulatory Body. This work, on the opposite, briefly reviews the Global Nuclear Safety Regime, and concentrates in detail in the discussion of its impact in Brazil, showing how it has produced some changes, and where the peer pressure regime has failed to produce real results

  2. Electron velocity shear driven instability in relativistic regime

    The electron magnetohydrodynamics model has been generalized to incorporate relativistic effects. The model is then employed to study the instability associated with sheared electron velocity flow in the relativistic regime. The instability has features similar to the conventional velocity shear driven Kelvin-Helmholtz-like mode [A. Das and P. Kaw, Phys. Plasmas 8, 4518 (2001)] in the weakly relativistic regime. However, in the strongly relativistic regime the instability shows certain distinct characteristics. The threshold value of the wave number is found to be considerably higher than the inverse shear width of the equilibrium velocity profile in this regime. Thus, the unstable domain of the wave-number space is considerably wider in this case. Also the mode does not remain purely growing but acquires a real frequency even for an antisymmetric velocity profile. These features of the mode have been understood by realizing that in the strongly relativistic regime the relativistic mass factor γ0 for the equilibrium has much sharper variations than that of the velocity profile.

  3. Early signatures of regime shifts in complex dynamical systems

    Indrani Bose; Mainak Pal

    2015-02-01

    A large number of studies have recently been carried out on the early signatures of regime shifts in a number of dynamical systems, e.g., ecosystems, the climate, fish and wildlife populations, financial markets, complex diseases and gene circuits. The underlying model in most cases is that of the fold-bifurcation in which a sudden regime shift occurs at a bifurcation point. The shift involves a discontinuous jump from one type of stable steady state to another. The dynamics of natural systems have both deterministic and stochastic components. The early signatures of abrupt regime shifts include the critical slowing down as a transition point is approached, rising variance and the lag-1 autocorrelation function, increased skewness of the steady-state probability distribution and the ratio of two mean first passage times for the exits from the stable steady states as the bifurcation point is approached. Noise-induced regime shifts are also possible for which the vicinity of the bifurcation point is not essential. In this paper, we review examples of regime shifts in natural systems and the associated early signatures. We further discuss how such approaches provide useful insights on a cell biological process involving the fold-bifurcation.

  4. Winter thermal regime of the LG 2 reservoir (James Bay)

    During winter, discharge from the stratified La Grande 2 reservoir affects the thermal regime of the downstream reach of the La Grande River, which in turn has repercussions on the hydraulic and ice regimes. The precision and reliability of modern electronic thermometers now permit automated electronically digitized data collection. Such instruments were installed in the large northern reservoir of the La Grande 2 powerplant and its downstream reach, to measure water temperatures during winter. Temperatures were recorded at depths ranging between 2 and 92 m and indicate a behaviour controlled mainly by the ice cover and the flow regime of the discharge at the LG 2 powerplant. Time series analyses performed in both time and frequency domains, provided information on the thermal regimes of the LG 2 reservoir and on the main layer of the flow drawn off by the powerplant. Field measurements from the 1988-89 and 1989-90 winter surveys are presented, and a description is presented of the water temperature regimes of the LG 2 reservoir and the downstream river. 3 refs., 14 figs

  5. Soil magnetic susceptibility reflects soil moisture regimes and the adaptability of tree species to these regimes

    Wang, J.-S.; Grimley, D.A.; Xu, C.; Dawson, J.O.

    2008-01-01

    Flooded, saturated or poorly drained soils are frequently anaerobic, leading to dissolution of the strongly magnetic minerals, magnetite and maghemite, and a corresponding decrease in soil magnetic susceptibility (MS). In this study of five temperate deciduous forests in east-central Illinois, USA, mean surface soil MS was significantly higher adjacent to upland tree species (31 ?? 10-5 SI) than adjacent to floodplain or lowland tree species (17 ?? 10-5 SI), when comparing regional soils with similar parent material of loessal silt. Although the sites differ in average soil MS for each tree species, the relative order of soil MS means for associated tree species at different locations is similar. Lowland tree species, Celtis occidentalis L., Ulmus americana L., Acer saccharinum L., Carya laciniosa (Michx. f.) Loud., and Fraxinus pennsylvanica Marsh. were associated with the lowest measured soil MS mean values overall and at each site. Tree species' flood tolerance rankings increased significantly, as soil MS values declined, the published rankings having significant correlations with soil MS values for the same species groups. The three published classifications of tree species' flood tolerance were significantly correlated with associated soil MS values at all sites, but most strongly at Allerton Park, the site with the widest range of soil drainage classes and MS values. Using soil MS measurements in forests with soil parent material containing similar initial levels of strongly magnetic minerals can provide a simple, rapid and quantitative method to classify soils according to hydric regimes, including dry conditions, and associated plant composition. Soil MS values thus have the capacity to quantify the continuum of hydric tolerances of tree species and guide tree species selection for reforestation. ?? 2007 Elsevier B.V. All rights reserved.

  6. Quantum SASE Regime for X-Ray FEL

    Avetissian, H K

    2005-01-01

    For the X-ray FEL if the amplifying photon energy is larger or comparable to resonance widths caused by an electron beam spreads or by the finite interaction length then the quantum effects may play a significant role [1] and the generation process shifts from the classical to the quantum regime. The recent advancement of high brightness particle and laser beams technology makes achievable the fulfillment of these conditions in the scheme of X-ray Backscatter Compton laser. In this work we consider in general the SASE X-ray FEL in the quantum regime of amplification arising from the self-consistent set of the Maxwell and relativistic quantum kinetic equations. It is shown a considerable increase in start-up and narrowing of the spectrum of the SASE power for amplifying X-ray frequencies compared with the classical SASE regime.

  7. Dynamo regimes and transitions in the VKS experiment

    Berhanu, M; Boisson, J; Gallet, B; Gissinger, C; Fauve, S; Mordant, N; Pétrélis, F; Bourgoin, M; Odier, P; Pinton, J -F; Plihon, N; Aumaître, S; Chiffaudel, A; Daviaud, F; Dubrulle, B; Pirat, C

    2015-01-01

    The Von K{\\'a}rm{\\'a}n Sodium experiment yields a variety of dynamo regimes, when asymmetry is imparted to the flow by rotating impellers at different speed F1 and F2. We show that as the intensity of forcing, measured as F1 + F2, is increased, the transition to a self-sustained magnetic field is always observed via a supercritical bifurcation to a stationary state. For some values of the asymmetry parameter $\\\\theta$ = (F1--F2)/(F1+F2), time dependent dynamo regimes develop. They are observed either when the forcing is increased for a given value of asymmetry, or when the amount of asymmetry is varied at sufficiently high forcing. Two qualitatively different transitions between oscillatory and stationary regimes are reported, involving or not a strong divergence of the period of oscillations. These transitions can be interpreted using a low dimensional model based on the interactions of two dynamo modes.

  8. Adelie penguin foraging location predicted by tidal regime switching.

    Matthew J Oliver

    Full Text Available Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator.

  9. Supercurrent in the quantum Hall regime, part II

    Amet, Francois; Ke, Chung Ting; Borzenets, Ivan; Wang, Jiyingmei; Watanabe, Kenji; Taniguchi, Takashi; Deacon, Russel; Yamamoto, Michihisa; Bomze, Yuriy; Tarucha, Seigo; Finkelstein, Gleb

    A novel promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall effect. Despite this potential, signatures of superconductivity in the quantum Hall regime remain scarce, and a superconducting current through a Landau-quantized two-dimensional electron gas has so far eluded experimental observation. High-mobility graphene/BN heterostructures exhibit the quantum Hall effect at relatively low field and are therefore particularly suitable to study the fate of the Josephson effect in that regime. Here, we report the observation of a superconducting current through graphene at fields as high as 2 Tesla. In that regime, the normal-state resistance is quantized but pockets of superconductivity still persist at small current bias. We will describe their bias and temperature dependence. Magnetic field interference patterns in the supercurrent inform on possible mechanisms mediating this supercurrent.

  10. A Markov Switching Regime Model of Malaysia Property Cycle

    Abdul M. Beksin

    2011-01-01

    Full Text Available Problem statement: Non-linear models such as the Markov Switching regime (MS method of modelling business cycles, in principle can be used to model property cyle. Approach: The MS model can distinguish property cycle in recession and expansion phases and is sufficiently flexible to allow different relationships to apply over these phases. In this study, the Malaysian property cycle is modelled using a MS model. Results: This technique can be used to simultaneously estimate the data generating process of real GDP growth and classify each observation into one of two regimes (i.e., low-growth and high-growth regimes. Conclusions: This finding has important policy implications, since the yield spread was used to generate the time-varying probabilities of the MS model as well as the recession probabilities of the logit model. In other words, a strong relationship exists between interest rates and the business cycle, where interest rates lead the business cycle.

  11. Dispersive regime of the Jaynes–Cummings and Rabi lattice

    Photon-based strongly correlated lattice models like the Jaynes–Cummings and Rabi lattices differ from their more conventional relatives like the Bose–Hubbard model by the presence of an additional tunable parameter: the frequency detuning between the pseudo-spin degree of freedom and the harmonic mode frequency on each site. Whenever this detuning is large compared to relevant coupling strengths, the system is said to be in the dispersive regime. The physics of this regime is well-understood at the level of a single Jaynes–Cummings or Rabi site. Here, we extend the theoretical description of the dispersive regime to lattices with many sites, for both strong and ultra-strong coupling. We discuss the nature and spatial range of the resulting qubit–qubit and photon–photon coupling, demonstrate the emergence of photon-pairing and squeezing and illustrate our results by exact diagonalization of the Rabi dimer. (paper)

  12. The difficulties of the Chinese and Indian exchange rate regimes

    Ila Patnaik

    2009-06-01

    Full Text Available China and India have both sought control over the exchange rate in order to maintain export competitiveness, manage current account balance, and pursue independent monetary policy. In this paper, we examine structural change in the Chinese and Indian de facto exchange rate regimes, focusing on the period from 1998 to 2007. With increasing capital account openness, exchange rate inflexibility has been associated with significant monetary policy distortions. In both countries, the short-term rate expressed in real terms dropped, and achieved very low values, in the unprecedented business cycle expansion of the early 2000s. In the Indian case, difficulties of sterilisation led to a modification of the exchange rate regime, moving towards greater flexibility. In China, in contrast, the exchange rate regime did not change.

  13. Oil Regime Change in Iraq. Possible Strategic Implications for OPEC

    The potential strategic impact of regime change in Iraq and Iran on OPEC in the long-run is explored. In the first part of the paper short overviews are given of the present international oil market; of US oil import issues and energy policy; of the strategic position of the US in the Persian Gulf and of geopolitical developments in the Persian Gulf at large. Also, attention is paid to the OPEC and the role of a 'new' Iraq. In the second part the game of 'boxed pigs' is used to explore the possible strategic impact of regime change in Iraq and possible regime change in Iran on OPEC. This exploration takes place within four possible futures for the Gulf

  14. Temporal evolution of flow regimes in urbanizing basins

    Mejia, A.; Rossel, F.; Gironas, J. A.; Jovanovic, T.

    2014-12-01

    We characterize the temporal evolution of the flow regime of urbanizing basins. By urbanizing basins, we mean basins that have experienced urban growth during their observation period. To represent the flow regime, we use flow duration curves (FDCs). We compute the FDCs using a stochastic model of daily streamflow for urban basins. In this case, the model aids in discerning the influence of key factors (e.g., climate, land use change, stormwater managenment conditions, and the slow and fast properties of the hydrologic response) on streamflow. To implement the model, we first divide the complete observation period of a given urban basin into intervals of equal duration, e.g. 5 years. Subsequently, we apply the model to each interval and this is how we capture the influence of land use changes and climatic fluctuations on the flow regime. We apply this modeling framework to 14 urbanizing basins in the Baltimore-Washington DC region. Results from this application indicate consistent changes in the temporal evolution of the altered flow regimes, which can largely be explained by the progressive redistribution with urban growth of water from slow subsurface runoff and evapotranspiration to fast urban runoff. We also use the modeling framework to determine indicators of ecohydrological alteration for urbanizing basins. The application of these indicators to our study area suggests that the flow regime is sensitive to alterations up to a certain level of urbanization after which sensitivity seems to level off. The flow regime also seems to be relatively more resistant to alterations for both the smaller and larger levels of urbanization considered. In the future, we would like to extend the application of the proposed modeling framework to other metropolitan areas.

  15. Modeling whistler wave generation regimes in magnetospheric cyclotron maser

    D. L. Pasmanik

    2004-11-01

    Full Text Available Numerical analysis of the model for cyclotron instability in the Earth's magnetosphere is performed. This model, based on the self-consistent set of equations of quasi-linear plasma theory, describes different regimes of wave generation and related energetic particle precipitation. As the source of free energy the injection of energetic electrons with transverse anisotropic distribution function to the interaction region is considered. A parametric study of the model is performed. The main attention is paid to the analysis of generation regimes for different characteristics of energetic electron source, such as the shape of pitch angle distributions and its intensity. Two mechanisms of removal of energetic electrons from a generation region are considered, one is due to the particle precipitation through the loss cone and another one is related to the magnetic drift of energetic particles.

    It was confirmed that two main regimes occur in this system in the presence of a constant particle source, in the case of precipitation losses. At small source intensity relaxation oscillations were found, whose parameters are in good agreement with simplified analytical theory developed earlier. At a larger source intensity, transition to a periodic generation occurs. In the case of drift losses the regime of self-sustained periodic generation regime is realized for source intensity higher than some threshold. The dependencies of repetition period and dynamic spectrum shape on the source parameters were studied in detail. In addition to simple periodic regimes, those with more complex spectral forms were found. In particular, alteration of spikes with different spectral shape can take place. It was also shown that quasi-stationary generation at the low-frequency band can coexist with periodic modulation at higher frequencies.

    On the basis of the results obtained, the model for explanation of

  16. Strong and moderate nonlinear El Niño regimes

    Takahashi, Ken; Dewitte, Boris

    2016-03-01

    It has been previously proposed that two El Niño (EN) regimes, strong and moderate, exist but the historical observational record is too short to establish this conclusively. Here, 1200 years of simulations with the GFDL CM2.1 model allowed us to demonstrate their existence in this model and, by showing that the relevant dynamics are also evident in observations, we present a stronger case for their existence in nature. In CM2.1, the robust bimodal probability distribution of equatorial Pacific sea surface temperature (SST) indices during EN peaks provides evidence for the existence of the regimes, which is also supported by a cluster analysis of these same indices. The observations agree with this distribution, with the EN of 1982-1983 and 1997-1998 corresponding to the strong EN regime and all the other observed EN to the moderate regime. The temporal evolution of various indices during the observed strong EN agrees very well with the events in CM2.1, providing further validation of this model as a proxy for nature. The two regimes differ strongly in the magnitude of the eastern Pacific warming but not much in the central Pacific. Observations and model agree in the existence of a finite positive threshold in the SST anomaly above which the zonal wind response to warming is strongly enhanced. Such nonlinearity in the Bjerknes feedback, which increases the growth rate of EN events if they reach sufficiently large amplitude, is very likely the essential mechanism that gives rise to the existence of the two EN regimes. Oceanic nonlinear advection does not appear essential for the onset of strong EN. The threshold nonlinearity could make the EN regimes very sensitive to stochastic forcing. Observations and model agree that the westerly wind stress anomaly in the central equatorial Pacific in late boreal summer has a substantial role determining the EN regime in the following winter and it is suggested that a stochastic component at this time was key for the

  17. Focal shift of silicon microlens in mid-infrared regime

    Zuo, Haijie; Ying, Leiying; Zhang, Baoping; Hou, Zhijin; Chen, Hongxu; Si, Junjie

    2016-01-01

    In this study, rigorous numerical calculation was utilized to characterize the focal properties of mid-infrared silicon microlens with the size about tens of micrometers. It is found that the focal shift phenomenon also exists in mid-infrared regime, which behaves differently from that of visual and near-infrared wavelength. Focal properties of silicon microlens were also measured experimentally, showing well coherence with simulation results. Our results provide systemic understanding of focal shift in mid-infrared regime, at that wavelength special consideration should be paid in micro-nano optics, especially with the integration between infrared optical system and other devices.

  18. NAZI REGIME IN THE PERIODICAL A NOTÍ­CIA.

    Bruna Luíza Barcellos

    2009-08-01

    Full Text Available The periodical A Notícia, of Joinville, city colonized for Germans, supported the nazi regime since the ascension of Adolf Hitler to the power. Between 1932 and 1944, some editions had printed the figure of Hitler and the nazi symbol, beyond dither messages to that regime. Based in the Análise de conteúdo (BARDIN, 1977, this article searchs to understand the representation made for the periodical A Notícia on this historical landmark, in other words, bring to the light the consequences of a part of occured world-wide history in catarinense territory.

  19. Development and current trends in the international nonproliferation regime

    The IAEA and its safeguards system is placed into a historical perspective. A personal perspective on the nonproliferation regime and on the Agency's role in it is then presented. This is done initially by discussing some of the landmark events in the history of the nonproliferation regime. Subsequently some of the history of arms control agreements and of the role of the IAEA are noted. Then political motivations of state and ways the Agency has an impact in the political nonproliferation sphere are addressed

  20. Using Clustering to Establish Climate Regimes from PCM Output

    Oglesby, Robert; Arnold, James E. (Technical Monitor); Hoffman, Forrest; Hargrove, W. W.; Erickson, D.

    2002-01-01

    A multivariate statistical clustering technique--based on the k-means algorithm of Hartigan has been used to extract patterns of climatological significance from 200 years of general circulation model (GCM) output. Originally developed and implemented on a Beowulf-style parallel computer constructed by Hoffman and Hargrove from surplus commodity desktop PCs, the high performance parallel clustering algorithm was previously applied to the derivation of ecoregions from map stacks of 9 and 25 geophysical conditions or variables for the conterminous U.S. at a resolution of 1 sq km. Now applied both across space and through time, the clustering technique yields temporally-varying climate regimes predicted by transient runs of the Parallel Climate Model (PCM). Using a business-as-usual (BAU) scenario and clustering four fields of significance to the global water cycle (surface temperature, precipitation, soil moisture, and snow depth) from 1871 through 2098, the authors' analysis shows an increase in spatial area occupied by the cluster or climate regime which typifies desert regions (i.e., an increase in desertification) and a decrease in the spatial area occupied by the climate regime typifying winter-time high latitude perma-frost regions. The patterns of cluster changes have been analyzed to understand the predicted variability in the water cycle on global and continental scales. In addition, representative climate regimes were determined by taking three 10-year averages of the fields 100 years apart for northern hemisphere winter (December, January, and February) and summer (June, July, and August). The result is global maps of typical seasonal climate regimes for 100 years in the past, for the present, and for 100 years into the future. Using three-dimensional data or phase space representations of these climate regimes (i.e., the cluster centroids), the authors demonstrate the portion of this phase space occupied by the land surface at all points in space and time

  1. Terahertz Quantum Plasmonics of Nanoslot Antennas in Nonlinear Regime.

    Kim, Joon-Yeon; Kang, Bong Joo; Park, Joohyun; Bahk, Young-Mi; Kim, Won Tae; Rhie, Jiyeah; Jeon, Hyeongtag; Rotermund, Fabian; Kim, Dai-Sik

    2015-10-14

    Quantum tunneling in plasmonic nanostructures has presented an interesting aspect of incorporating quantum mechanics into classical optics. However, the study has been limited to the subnanometer gap regime. Here, we newly extend quantum plasmonics to gap widths well over 1 nm by taking advantage of the low-frequency terahertz regime. Enhanced electric fields of up to 5 V/nm induce tunneling of electrons in different arrays of ring-shaped nanoslot antennas of gap widths from 1.5 to 10 nm, which lead to a significant nonlinear transmission decrease. These observations are consistent with theoretical calculations considering terahertz-funneling-induced electron tunneling across the gap. PMID:26372787

  2. Switching Monetary Policy Regimes and the Nominal Term Structure

    Ferman, Marcelo

    2011-01-01

    In this paper I propose a regime-switching approach to explain why the U.S. nominal yield curve on average has been steeper since the mid-1980s than during the Great Inflation of the 1970s. I show that, once the possibility of regime switches in the short-rate process is incorporated into investors' beliefs, the average slope of the yield curve generally will contain a new component called 'level risk'. Level-risk estimates, based on a Markov-Switching VAR model of the U.S. economy, are then ...

  3. Measurement of flow in supercritical flow regime using cutthroat flumes

    Shrikant A Tekade; Avinash D Vasudeo; Aniruddha D Ghare; Ramesh N Ingle

    2016-02-01

    Cutthroat flume is commonly used for measurement of subcritical flow in open channel because of its simplicity and ease of construction. No experimental data is available in literature for measurement of flow in supercritical regime using cutthroat flume. The present paper finds the feasibility of cutthroat flume as a measurement device for flow in supercritical regime. Experimental data are generated to develop the relation between discharge and observed head at a specified location on upstream of throat section. Regression analysis for discharge and head indicated a good correlation. Based on all the experimental data generated, a relationship between discharge and head is proposed.

  4. Water regime and core state in WWER reactors

    Some features of the ammonia-potassium water regime used in the WWER-reactors are considered. This regime makes it possible to suppress water radiolysis and simultaneously obtain a high pH value of the coolant, which is necessary in operation with boron control of the reactor power. Absence of oxygen and significant deposits on the zirconium alloy claddings of the fuel elements affect favourably the corrosion condition of the core. The thickness of the corrosion film on the fuel cladding at the end of their lifetime is as low as 3μm and the hydrogen content remains at the initial level

  5. Explicit Mapping of Acoustic Regimes For Wind Instruments

    Missoum, Samy; Doc, Jean-Baptiste

    2014-01-01

    This paper proposes a methodology to map the various acoustic regimes of wind instruments. The maps can be generated in a multi-dimensional space consisting of design, control parameters, and initial conditions. The bound- aries of the maps are obtained explicitly in terms of the parameters using a support vector machine (SVM) classifier as well as a dedicated adaptive sam- pling scheme. The approach is demonstrated on a simplified clarinet model for which several maps are generated based on different criteria. Examples of computation of the probability of occurrence of a specific acoustic regime are also provided. In addition, the approach is demonstrated on a design optimization example for optimal intonation.

  6. The French regime of civil liability for nuclear

    As civil liability for nuclear is a matter of discussion and initiatives at the European and international levels, the author proposes an overview of the legal framework of the French regime of civil liability for nuclear which is a combination of two international treaties (Paris and Brussels conventions) and a national arrangement (a 1968 law). He presents and comments the main characteristics of this regime (geographical scope of application, concerned activities, excluded events, covered damages, principles regarding operator's liability) and the improvements brought by Paris and Brussels convention review protocols

  7. Explicit mapping of acoustic regimes for wind instruments

    Missoum, Samy; Vergez, Christophe; Doc, Jean-Baptiste

    2014-09-01

    This paper proposes a methodology to map the various acoustic regimes of wind instruments. The maps can be generated in a multidimensional space consisting of design, control parameters, and initial conditions. The boundaries of the maps are obtained explicitly in terms of the parameters using a Support Vector Machine (SVM) classifier as well as a dedicated adaptive sampling scheme. The approach is demonstrated on a simplified clarinet model for which several maps are generated based on different criteria. Examples of computation of the probability of occurrence of a specific acoustic regime are also provided. In addition, the approach is demonstrated on a design optimization example for optimal intonation.

  8. PREDICTION OF FLOW REGIMES IN SPOUT-FLUIDIZED BEDS

    Jiyu Zhang; Fengxiang Tang

    2006-01-01

    Five main flow regimes in spout-fluidized bed were identified in this study, namely, fixed bed, spout with aeration, spout-fluidization, jet in fluidized bed and slugging, together with their corresponding major frequencies translated from pressure signals. The empirical equation A=aBb, in which A=Fr* /(H/Di) and B=(Fr*/(H/D))/(μg/μmf) are respectively the spout-geometry and spout-geometry-fluidization dimensionless numbers, was proposed to distinguish these flow regimes.

  9. Electron Vacuum Acceleration in a Regime beyond Brunel Absorption

    We describe a new regime of electron acceleration in laser plasmas driven by ultrafast pulses of relativistic intensity, in which space-charge separation leads to strongly enhanced laser absorption and the production of 20 MeV (p/m0c≅40) electrons driven outward in vacuum. 1D PIC simulations show that intense attosecond pulses generated around critical density can sweep electrons outward over many wavelengths in distance. With increasing interaction scale length, absorption generalizes from the Brunel regime to one in which absorption is primarily into electrons of energy >>5 MeV.

  10. Non-linear regimes in resistive MHD equations

    The resistive MHD equations in ''slab'' geometry and helical symmetry are considered in a dissipative dynamical system approach with the aim to elucidate the basic mechanisms for the non-linear regimes in plasmas. One-dimensional equilibria are found to be destabilised via symmetry breaking bifurcation to stationary solutions with ''island-vortex'' structures. Conditions are discussed for which further destabilisation to time-dependent regimes at higher Reynolds number leads to ''sawtooth-like'' oscillations. The ''crash'' in magnetic energy is found to be due to a fast drop for the one-dimensional magnetic field connected with enhancement of ''island-vortex'' activity. (Author)

  11. Process-based humidity control regime for greenhouse crops

    Korner, O.; Challa, H.

    2003-01-01

    Modern greenhouses in The Netherlands are designed for efficient use of energy. Climate control traditionally aims at optimal crop performance. However, energy saving is a major issue for the development of new temperature regimes. Temperature integration (TI) results in fluctuating and often high r

  12. Analysis of the Two-Regime Method on Square Meshes

    Flegg, Mark B.

    2014-01-01

    The two-regime method (TRM) has been recently developed for optimizing stochastic reaction-diffusion simulations [M. Flegg, J. Chapman, and R. Erban, J. Roy. Soc. Interface, 9 (2012), pp. 859-868]. It is a multiscale (hybrid) algorithm which uses stochastic reaction-diffusion models with different levels of detail in different parts of the computational domain. The coupling condition on the interface between different modeling regimes of the TRM was previously derived for onedimensional models. In this paper, the TRM is generalized to higher dimensional reaction-diffusion systems. Coupling Brownian dynamics models with compartment-based models on regular (square) two-dimensional lattices is studied in detail. In this case, the interface between different modeling regimes contains either flat parts or right-angle corners. Both cases are studied in the paper. For flat interfaces, it is shown that the one-dimensional theory can be used along the line perpendicular to the TRM interface. In the direction tangential to the interface, two choices of the TRM parameters are presented. Their applicability depends on the compartment size and the time step used in the molecular-based regime. The two-dimensional generalization of the TRM is also discussed in the case of corners. © 2014 Society for Industrial and Applied Mathematics.

  13. Search Regimes and the Industrial Dynamics of Science

    Bonaccorsi, Andrea

    2008-01-01

    The article addresses the issue of dynamics of science, in particular of new sciences born in twentieth century and developed after the Second World War (information science, materials science, life science). The article develops the notion of search regime as an abstract characterization of dynamic patterns, based on three dimensions: the rate of…

  14. Syria: The Consolidation of the Asad Regime, 1970-1975.

    Olson, Robert W.

    1982-01-01

    Up to 1975-76, Syria's Hafiz al-Asad was successful in consolidating his power, securing the maintenance of his regime, and broadening his base of political power. His system started weakening in 1975 due to increased opposition stemming from Syria's intervention in the Lebanese civil war. (AM)

  15. Just for Fun? The Emotional Regime of Experiential Consumption

    Jantzen, Christian; Fitchett, James; Østergaard, Per;

    2012-01-01

    Experiential consumption emphasizes emotional and hedonic qualities in the marketplace stressing the importance of experiences for ‘the good life’ and positioning consumption as a legitimate way to generate interesting and relevant experiences. The concept of emotional regimes (Reddy, 2001) is us...... the sake of self-actualization....

  16. Understanding shifts in wildfire regimes as emergent threshold phenomena.

    Zinck, Richard D; Pascual, Mercedes; Grimm, Volker

    2011-12-01

    Ecosystems driven by wildfire regimes are characterized by fire size distributions resembling power laws. Existing models produce power laws, but their predicted exponents are too high and fail to capture the exponent's variation with geographic region. Here we present a minimal model of fire dynamics that describes fire spread as a stochastic birth-death process, analogous to stochastic population growth or disease spread and incorporating memory effects from previous fires. The model reproduces multiple regional patterns in fire regimes and allows us to classify different regions in terms of their proximity to a critical threshold. Transitions across this critical threshold imply abrupt and pronounced increases in average fire size. The model predicts that large regions in Canada are currently close to this transition and might be driven beyond the threshold in the future. We illustrate this point by analyzing the time series for large fires (>199 ha) from the Canadian Boreal Plains, found to have shifted from a subcritical regime to a critical regime in the recent past. By contrast to its predecessor, the model also suggests that a critical transition, and not self-organized criticality, underlies forest fire dynamics, with implications for other ecological systems exhibiting power-law-like patterns, in particular for their sensitivity to environmental change and control efforts. PMID:22089877

  17. Regime-switching models to study psychological process

    Hamaker, E.L.; Grasman, R.P.P.P.; Kamphuis, J.H.

    2010-01-01

    Many psychological processes are characterized by recurrent shifts between different states. To model these processes at the level of the individual, regime-switching models may prove useful. In this chapter we discuss two of these models: the threshold autoregressive model and the Markov switching

  18. Influence of vegetation cover on thermal regime of mountainous catchments

    Tesař, Miroslav; Šír, Miloslav; Lichner, Ľ.; Zelenková, E.

    2006-01-01

    Roč. 61, Suppl. 19 (2006), S311-S314. ISSN 1335-6372 R&D Projects: GA ČR GA205/05/2312 Institutional research plan: CEZ:AV0Z20600510 Keywords : climate * plant transpiration * thermal regime Subject RIV: DA - Hydrology ; Limnology

  19. Towards an Orderly Exit Regime in English Higher Education

    Fisher, Andrew

    2016-01-01

    In a competitive market, the exit of those suppliers who cannot offer an attractive product at an attractive price is seen as desirable. However, the consequences for consumers when their own supplier leaves the market in an unplanned or disorderly way may be undesirable. Exit regimes exist in regulated markets to ensure that consumers are not…

  20. Oil and gas fiscal regimes of the western Canadian provinces

    This report compares the fiscal regimes in British Columbia, Alberta, Saskatchewan and Manitoba. During 1985-1988, federal and provincial governments have made numerous fiscal changes, many in response to the drop in world oil prices. The new fiscal policies generally have reflected governments' willingness to forego revenues in an effort to aid the oil and gas industry, with certain exemptions. Since 1988, changes have reflected trends of consolidation and less government willingness to forego revenues. A federal large corporations capital tax has been introduced, the natural gas exploration holiday in Alberta expired, new oil royalties were introduced, and changes were made in fiscal regimes to accomodate horizontal drilling in Saskatchewan and Manitoba. In this document, the existing corporate tax regime is described. A comparison of fiscal regimes must recognize the differing scale and nature of oil and gas operations among the 4 provinces, with Alberta accounting for 80-90% of Canada's oil and gas productions, while British Columbia, Saskatchewan and Manitoba are much smaller producers. The document describes Crown royalties and incentives and freehold taxes for each type of fuel (crude oil, natural gas, natural gas byproducts, nonconventional oil). 8 figs

  1. Learning, competency nomads, and post-signifying regimes

    Krejsler, John

    2007-01-01

    of these changes as a transition from ‘industrial' to ‘knowledge society'; this is done by re-describing this transition from within as a transition from ‘signifying' to ‘post-signifying' regimes. From this conceptual experiment the ‘competency nomad' emerges as a powerful concept that seems useful...

  2. Operating regimes of signaling cycles: statics, dynamics, and noise filtering.

    Carlos Gomez-Uribe

    2007-12-01

    Full Text Available A ubiquitous building block of signaling pathways is a cycle of covalent modification (e.g., phosphorylation and dephosphorylation in MAPK cascades. Our paper explores the kind of information processing and filtering that can be accomplished by this simple biochemical circuit. Signaling cycles are particularly known for exhibiting a highly sigmoidal (ultrasensitive input-output characteristic in a certain steady-state regime. Here, we systematically study the cycle's steady-state behavior and its response to time-varying stimuli. We demonstrate that the cycle can actually operate in four different regimes, each with its specific input-output characteristics. These results are obtained using the total quasi-steady-state approximation, which is more generally valid than the typically used Michaelis-Menten approximation for enzymatic reactions. We invoke experimental data that suggest the possibility of signaling cycles operating in one of the new regimes. We then consider the cycle's dynamic behavior, which has so far been relatively neglected. We demonstrate that the intrinsic architecture of the cycles makes them act--in all four regimes--as tunable low-pass filters, filtering out high-frequency fluctuations or noise in signals and environmental cues. Moreover, the cutoff frequency can be adjusted by the cell. Numerical simulations show that our analytical results hold well even for noise of large amplitude. We suggest that noise filtering and tunability make signaling cycles versatile components of more elaborate cell-signaling pathways.

  3. The Treaty of Lisbon and the European Border Control Regime

    Marianne Takle

    2012-08-01

    Full Text Available The question raised in the article is how the new provisions of the Lisbon Treaty and the Stockholm programme concerning the EU’s asylum and migration policy might consolidate existing trends within the European border control regime. The regime is defined by a combination of three features: (i a harmonisation of categories among the EU/Schengen member states, (ii a growing use of new technology in networked databases and (iii an increasing sorting of individuals based on security concerns. Although none of these features is new, the combination gives a new impetus to the European border control regime. The article concludes that the Lisbon Treaty and the Stockholm programme consolidate and strengthen existing trends. This implies that policies on border control, asylum, immigration, judicial cooperation and police cooperation are consolidated in a broader approach to border control, and that there is a strengthening of EU foreign policy within the European border control regime. The boundaries between previously dispersed policy areas are blurred. The combination of different aspects of security and various levels of authority requires coordination of policies with substantially different goals, and goes beyond mere border control.

  4. Announced regime switch: optimal policy for transition period

    Brázdik, František

    -, č. 402 (2009), s. 1-49. ISSN 1211-3298 Institutional research plan: CEZ:MSM0021620846 Keywords : new Keynesian models * small open economy * monetary regime Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp402.pdf

  5. Exploiting synergies between nonproliferation verification regimes: A pragmatic approach

    This paper considers the potential for expanding interaction and exploiting synergies between different multilateral disarmament and nonproliferation regimes. It concludes that although there are political barriers to high-level and pervasive synergization, there are opportunities for pragmatic, functional steps to be taken as a way of building confidence and experience. (author)

  6. Globalisation, the "Idea of a University" and Its Ethical Regimes

    Marginson, Simon

    2007-01-01

    This paper sketches the impact of globalisation and internationalisation on the terrain of values and ethics in higher education. The first part of the paper discusses values and ethics in higher education in relation to the "Idea of a University", and identifies the ethical regimes essential to the functioning of HEIs as knowledge-forming…

  7. Defocusing regimes of nonlinear waves in media with negative dispersion

    Bergé, L.; Kuznetsov, E.A.; Juul Rasmussen, J.

    1996-01-01

    Defocusing regimes of quasimonochromatic waves governed by a nonlinear Schrodinger equation with mixed-sign dispersion are investigated. For a power-law nonlinearity, we show that localized solutions to this equation defined at the so-called critical dimension cannot collapse in finite time in th...

  8. Characterization of the Tokamak Novillo in cleaning regime

    In this work the obtained results of the investigation about the experimental characterization of those low energy pulsed discharges of the Tokamak Novillo are reported. With this it is possible to fix the one operation point but appropriate of the Tokamak to condition the chamber in the smallest possible time for the cleaning discharges regime before beginning the main discharge. The characterization of the cleaning discharges in those Tokamaks is an unique process and characteristic of each device, since the good points of operation are consequence of those particularities of the design of the machine. In the case of the Tokamak Novillo, besides characterizing it a contribution is made to the cleaning discharges regime which consists on the one product of the current peak to peak of plasma by the duration of the discharge Ipt like reference parameter for the optimization of the operation of the device in the cleaning discharge regime. The maximum value of the parameter I(p)t, under different work conditions, allowed to find the good operation point to condition the discharges chamber of the Tokamak Novillo in short time and to arrive to a regime in which is not necessary the preionization for the obtaining of the cleaning discharges. (Author)

  9. Alternative pricing regimes in Ontario : exploring the impacts

    Legislative goals were recently established in Ontario to promote reliability and quality of electricity service and to ensure that distribution rates for customers remain reasonable. This presentation explored the effect of changing electricity pricing structures on residential customers in Ontario. This study investigated a period between May to December 2005, in the town of Milton, Ontario. Monthly demand was measured for each month, and monthly weighted averages were presented. Residents with electric heating were removed from the sample. Four pricing structure scenarios were examined: (1) flat rates; (2) time-of-use pricing regimes; (3) real time pricing regimes; and (4) critical peak pricing. Average monthly consumption rates for July and August for all 4 scenarios were presented. Results for time-of-use were compared to flat rates, which showed a slight increase in monthly costs. Real time average monthly electricity costs were significantly higher. Time-of-use costs increased by 57 per cent during the periods examined. Real time pricing regimes resulted in a 196 per cent rise in costs. It was concluded that more research must be done to explore the policy implications of pricing regimes and their effect on consumer behaviour. refs., tabs., figs

  10. Multi-fluid modeling of low-recycling divertor regimes

    The low-recycling regimes of divertor operation in a single-null NSTX magnetic configuration are studied using computer simulations with the edge plasma transport code UEDGE. The edge plasma transport properties pertinent to the low-recycling regimes are demonstrated. These include the flux-limited character of the parallel heat transport and the high plasma temperatures with the flattened profiles in the scrape-off-layer. It is shown that to maintain the balance of particle fluxes at the core interface the deuterium gas puffing rate should increase as the divertor recycling coefficient decreases. The radial profiles of the heat load to the outer divertor plate, the upstream radial plasma profiles, and the effects of the cross-field plasma transport in the low-recycling regimes are discussed. It is also shown that recycling of lithium impurities evaporating from the divertor plate at high surface temperatures can reverse the low-recycling divertor operational regime to the high-recycling one and may cause thermal instability of the divertor plate (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Microgravity Flow Regime Data: Buoyancy and Mixing Apparatus Effects

    Shephard, Adam; Best, Frederick

    2010-01-01

    Zero-g two-phase flow data set qualification and flight experiment design have not been standardized and as a result, agreement among researchers has not been reached regarding what experimental conditions adequately approximate those of microgravity. The effects of buoyancy forces and mixing apparatus on the flow regime transitions are presented in this study. The gravity conditions onboard zero-g aircraft are at best 10-3 g which is used to approximate the 10-5 g conditions of microgravity, thus the buoyancy forces present on zero-g aircraft can become significantly large and unrepresentative of microgravity. When buoyancy forces approach those of surface tension forces, buoyancy induced coalescence occurs. When discussing flow regime transitions, these large buoyancy forces lead to flow regime transitions which otherwise would not occur. The buoyancy attributes of the two-phase flow data sets available in the literature are evaluated to determine which data sets exhibit buoyancy induced transitions. Upon comparison of the representative data sets, the affects of different mixing apparatus can be seen in the superficial velocity flow regime maps.

  12. Second regime tokamak operation at large aspect ratio

    The equilibrium, stability, and transport properties of large aspect ratio tokamaks operating at the second stability regime are described theoretically using numerical and analytical techniques. It has been shown that, at large aspect ratio, significant current profile control is possible with relatively modest amounts of neutral beam current drive, and the power needed to access and maintain the second regime operation is calculated to be about 3 MW using the results of an integrated 1.5D transport and stability code. An example second regime experiment has been described and the results are presented of extensive calculations illustrating several possible operating scenarios, external and internal model stability boundaries, and the experimental features needed to evaluate and test the high beta tokamak theories. The theory which describes the stabilizing effect of energetic particles during high beta operation was extended to finite aspect ratio. A key technical problem for application of this technique appears to be caused by ripple transport. Plasma rotation effects are found to be generally destabilizing and several other schemes for improved access to the second stability regime are discussed including ponderomotive stabilization of the plasma edge region and active feedback control

  13. Regular and Chaotic Regimes in Scalar Field Cosmology

    Alexey V. Toporensky

    2006-03-01

    Full Text Available A transient chaos in a closed FRW cosmological model with a scalar field is studied. We describe two different chaotic regimes and show that the type of chaos in this model depends on the scalar field potential. We have found also that for sufficiently steep potentials or for potentials with large cosmological constant the chaotic behavior disappears.

  14. Intergenerational Justice Perceptions and the Role of Welfare Regimes

    Sabbagh, Clara; Vanhuysse, Pieter

    2010-01-01

    , different welfare regimes structure young people's perceptions of the justness of public resources transfers from young to elderly age-groups and (2) the perceived relative contributions and rewards of various age-groups. Thus we inquire about both the perceived support in principle and about the perceived...

  15. Primordial black holes in linear and non-linear regimes

    Allahyari, Alireza; Abolhasani, Ali Akbar

    2016-01-01

    Using the concept of apparent horizon for dynamical black holes, we revisit the formation of primordial black holes (PBH) in the early universe for both linear and non-linear regimes. First, we develop the perturbation theory for spherically symmetric spacetimes to study the formation of spherical PBHs in linear regime and we fix two gauges. We also introduce a well defined gauge invariant quantity for the expansion. Using this quantity, we argue that PBHs do not form in the linear regime. Finally, we study the non-linear regime. We adopt the spherical collapse picture by taking a closed FRW model in the radiation dominated era to investigate PBH formation. Taking the initial condition of the spherical collapse from the linear theory of perturbations, we allow for both density and velocity perturbations. Our model gives a constraint on the velocity perturbation. This model also predicts that the apparent horizon of PBHs forms when $\\delta > 3$. Applying the sound horizon constraint, we have shown the threshol...

  16. Perfect photon absorption in nonlinear regime of cavity quantum electrodynamics

    Agarwal, G S; Wang, Liyong; Zhu, Yifu

    2016-01-01

    It has been shown that perfect photon absorption can occur in the linear excitation regime of cavity quantum electrodynamics (CQED), in which photons from two identical light fields coupled into two ends of the cavity are completely absorbed and result in excitation of the polariton state of the CQED system. The output light from the cavity is totally suppressed by the destructive interference and the polariton state can only decay incoherently back to the ground state. Here we analyze the perfect photon absorption and onset of optical bistability in the nonlinear regime of the CQED and show that the perfect photon absorption persists in the nonlinear regime of the CQED below the threshold of the optical bistability. Therefore the perfect photon absorption is a phenomenon that can be observed in both linear and nonlinear regimes of CQED. Furthermore, our study reveals for the first time that the optical bistability is influenced by the input-light interference and can be manipulated by varying the relative ph...

  17. Institutional Regimes and Induced Dependency in Homes for the Aged.

    Booth, Tim

    1986-01-01

    Reports effects of institutional regimes on levels of dependency among residents of public homes for the elderly in England. Differences in management practices and caring routines did not affect the creation or reduction of dependency among residents. Questions the rationale that informs some current notions of good practice in residential work.…

  18. Accessing Imagined Communities and Reinscribing Regimes of Truth

    Carroll, Sherrie; Motha, Suhanthie; Price, Jeremy N.

    2008-01-01

    In this article, we explore the complex and nebulous terrain between two theoretical concepts, imagined communities (Norton, 2000, 2001), that is, individuals' imagined affiliations with certain groups, and regimes of truth (Foucault, 1980), dominant images inscribed and reinscribed into individual consciousness until they become normative. Using…

  19. Predicting weather regime transitions in Northern Hemisphere datasets

    Kondrashov, D. [University of California, Department of Atmospheric and Oceanic Sciences and Institute of Geophysics and Planetary Physics, Los Angeles, CA (United States); Shen, J. [UCLA, Department of Statistics, Los Angeles, CA (United States); Berk, R. [UCLA, Department of Statistics, Los Angeles, CA (United States); University of Pennsylvania, Department of Criminology, Philadelphia, PA (United States); D' Andrea, F.; Ghil, M. [Ecole Normale Superieure, Departement Terre-Atmosphere-Ocean and Laboratoire de Meteorologie Dynamique (CNRS and IPSL), Paris Cedex 05 (France)

    2007-10-15

    A statistical learning method called random forests is applied to the prediction of transitions between weather regimes of wintertime Northern Hemisphere (NH) atmospheric low-frequency variability. A dataset composed of 55 winters of NH 700-mb geopotential height anomalies is used in the present study. A mixture model finds that the three Gaussian components that were statistically significant in earlier work are robust; they are the Pacific-North American (PNA) regime, its approximate reverse (the reverse PNA, or RNA), and the blocked phase of the North Atlantic Oscillation (BNAO). The most significant and robust transitions in the Markov chain generated by these regimes are PNA {yields} BNAO, PNA {yields} RNA and BNAO {yields} PNA. The break of a regime and subsequent onset of another one is forecast for these three transitions. Taking the relative costs of false positives and false negatives into account, the random-forests method shows useful forecasting skill. The calculations are carried out in the phase space spanned by a few leading empirical orthogonal functions of dataset variability. Plots of estimated response functions to a given predictor confirm the crucial influence of the exit angle on a preferred transition path. This result points to the dynamic origin of the transitions. (orig.)

  20. Regimes of flow induced vibration for tandem, tethered cylinders

    Nave, Gary; Stremler, Mark

    2015-11-01

    In the wake of a bluff body, there are a number of dynamic response regimes that exist for a trailing bluff body depending on spacing, structural restoring forces, and the mass-damping parameter m* ζ . For tandem cylinders with low values of m* ζ , two such regimes of motion are Gap Flow Switching and Wake Induced Vibration. In this study, we consider the dynamics of a single degree-of-freedom rigid cylinder in the wake of another in these regimes for a variety of center-to-center cylinder spacings (3-5 diameters) and Reynolds numbers (4,000-11,000). The system consists of a trailing cylinder constrained to a circular arc around a fixed leading cylinder, which, for small angle displacements, bears a close resemblance to the transversely oscillating cylinders found more commonly in existing literature. From experiments on this system, we compare and contrast the dynamic response within these two regimes. Our results show sustained oscillations in the absence of a structural restoring force in all cases, providing experimental support for the wake stiffness assumption, which is based on the mean lift toward the center line of flow.

  1. Political regime and human capital: A cross-country analysis

    Klomp, J.G.; Haan, de J.

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human ca

  2. Political regime and human capital : A cross-country analysis

    Klomp, J.G.; de Haan, J.

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human ca

  3. Political Regime and Human Capital: A Cross-Country Analysis

    Klomp, Jeroen; de Haan, Jakob

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human capital). In the second step, we estimate the…

  4. Regime shifts, resilience and recovery of a cod stock

    Lindegren, Martin; Diekmann, Rabea; Möllmann, Christian

    2010-01-01

    In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...

  5. Nonlinear regimes in mean-field full-sphere dynamo

    Pipin, V V

    2016-01-01

    The mean-field dynamo model is employed to study the non-linear dynamo regimes in a fully convective star of mass 0.3$M_{\\odot}$ rotating with period of 10 days. The differential rotation law was estimated using the mean-field hydrodynamic and heat transport equations. For the intermediate parameter of the turbulent magnetic Reynolds number, $Pm_{T}=3$ we found the oscillating dynamo regimes with period about 40Yr. The higher $Pm_{T}$ results to longer dynamo periods. The meridional circulation has one cell per hemisphere. It is counter-clockwise in the Northen hemisphere. The amplitude of the flow at the surface around 1 m/s. Tne models with regards for meridional circulation show the anti-symmetric relative to equator magnetic field. If the large-scale flows is fixed we find that the dynamo transits from axisymmetric to non-axisymmetric regimes for the overcritical parameter of the $\\alpha$effect. The change of dynamo regime occurs because of the non-axisymmetric non-linear $\\alpha$-effect. The situation pe...

  6. Welfare Attitudes and Social Expenditure: Do Regimes Shape Public Opinion?

    Jakobsen, Tor Georg

    2011-01-01

    This article examines the link between regime types, social expenditure, and welfare attitudes. By employing data on 19 countries taken from the World Values Survey, the main aim is to see to what degree the institutions of a country affect the attitudes of its citizens. According to Esping-Andersen ("The three worlds of welfare capitalism".…

  7. Detection and Assessment of Ecosystem Regime Shifts from Fisher Information

    B. Roy Frieden

    2008-06-01

    Full Text Available Ecosystem regime shifts, which are long-term system reorganizations, have profound implications for sustainability. There is a great need for indicators of regime shifts, particularly methods that are applicable to data from real systems. We have developed a form of Fisher information that measures dynamic order in complex systems. Here we propose the use of Fisher information as a means of: (1 detecting dynamic regime shifts in ecosystems, and (2 assessing the quality of the shift in terms of intensity and pervasiveness. Intensity is reflected by the degree of change in dynamic order, as determined by Fisher information, and pervasiveness is a reflection of how many observable variables are affected by the change. We present a new robust methodology to calculate Fisher information from time series field data. We demonstrate the use of Fisher information to detect regime shifts on a model for a shallow lake. Next, we use Fisher information to analyze marine ecosystem response to physical changes using real time-series data of a coastal marine ecosystem, the North Pacific Ocean.

  8. Limit Operation Regimes of DC Actuator-Based Linear Drives

    Barglik, J.; Doležel, Ivo; Dvořák, P.; Škopek, M.; Ulrych, B.

    Vol. 2. Poznan: Poznan University of Technology, 2004 - (Nawrowski, R.), s. 600-611 ISBN 83-912306-6-X R&D Projects: GA MŠk LN00B084 Keywords : DC actuators * operation regime * electromagnetic field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  9. Interchannel stability analysis of oscillatory instable parallel channel two phase flow regimes

    Conditions for interchannel hydrodynamic stability of oscillatory unstable parallel channel two-phase flow regimes are being analysed. For experimental determined transfer functions Nyquist diagrams for one-phase and two-phase flow regimes are being considered. The results are presented show interchannel stability oscillatory unstable linear experimental regimes and interchannel instability nonlinear experimental regimes

  10. The human dimension of fire regimes on Earth.

    Bowman, David M J S; Balch, Jennifer; Artaxo, Paulo; Bond, William J; Cochrane, Mark A; D'Antonio, Carla M; Defries, Ruth; Johnston, Fay H; Keeley, Jon E; Krawchuk, Meg A; Kull, Christian A; Mack, Michelle; Moritz, Max A; Pyne, Stephen; Roos, Christopher I; Scott, Andrew C; Sodhi, Navjot S; Swetnam, Thomas W; Whittaker, Robert

    2011-12-01

    Humans and their ancestors are unique in being a fire-making species, but 'natural' (i.e. independent of humans) fires have an ancient, geological history on Earth. Natural fires have influenced biological evolution and global biogeochemical cycles, making fire integral to the functioning of some biomes. Globally, debate rages about the impact on ecosystems of prehistoric human-set fires, with views ranging from catastrophic to negligible. Understanding of the diversity of human fire regimes on Earth in the past, present and future remains rudimentary. It remains uncertain how humans have caused a departure from 'natural' background levels that vary with climate change. Available evidence shows that modern humans can increase or decrease background levels of natural fire activity by clearing forests, promoting grazing, dispersing plants, altering ignition patterns and actively suppressing fires, thereby causing substantial ecosystem changes and loss of biodiversity. Some of these contemporary fire regimes cause substantial economic disruptions owing to the destruction of infrastructure, degradation of ecosystem services, loss of life, and smoke-related health effects. These episodic disasters help frame negative public attitudes towards landscape fires, despite the need for burning to sustain some ecosystems. Greenhouse gas-induced warming and changes in the hydrological cycle may increase the occurrence of large, severe fires, with potentially significant feedbacks to the Earth system. Improved understanding of human fire regimes demands: (1) better data on past and current human influences on fire regimes to enable global comparative analyses, (2) a greater understanding of different cultural traditions of landscape burning and their positive and negative social, economic and ecological effects, and (3) more realistic representations of anthropogenic fire in global vegetation and climate change models. We provide an historical framework to promote understanding

  11. The human dimension of fire regimes on Earth

    Bowman, David M.J.S.; Balch, Jennifer; Artaxo, Paulo; Bond, William J.; Cochrane, Mark A.; D'Antonio, Carla M.; DeFries, Ruth; Johnston, Fay H.; Keeley, Jon E.; Krawchuk, Meg A.; Kull, Christian A.; Michelle, Mack; Moritz, Max A.; Pyne, Stephen; Roos, Christopher I.; Scott, Andrew C.; Sodhi, Navjot S.; Swetnam, Thomas W.

    2011-01-01

    Humans and their ancestors are unique in being a fire-making species, but 'natural' (i.e. independent of humans) fires have an ancient, geological history on Earth. Natural fires have influenced biological evolution and global biogeochemical cycles, making fire integral to the functioning of some biomes. Globally, debate rages about the impact on ecosystems of prehistoric human-set fires, with views ranging from catastrophic to negligible. Understanding of the diversity of human fire regimes on Earth in the past, present and future remains rudimentary. It remains uncertain how humans have caused a departure from 'natural' background levels that vary with climate change. Available evidence shows that modern humans can increase or decrease background levels of natural fire activity by clearing forests, promoting grazing, dispersing plants, altering ignition patterns and actively suppressing fires, thereby causing substantial ecosystem changes and loss of biodiversity. Some of these contemporary fire regimes cause substantial economic disruptions owing to the destruction of infrastructure, degradation of ecosystem services, loss of life, and smoke-related health effects. These episodic disasters help frame negative public attitudes towards landscape fires, despite the need for burning to sustain some ecosystems. Greenhouse gas-induced warming and changes in the hydrological cycle may increase the occurrence of large, severe fires, with potentially significant feedbacks to the Earth system. Improved understanding of human fire regimes demands: (1) better data on past and current human influences on fire regimes to enable global comparative analyses, (2) a greater understanding of different cultural traditions of landscape burning and their positive and negative social, economic and ecological effects, and (3) more realistic representations of anthropogenic fire in global vegetation and climate change models. We provide an historical framework to promote understanding

  12. Early warning of atmospheric regime transitions using transfer operators

    Tantet, Alexis; Dijkstra, Henk

    2015-04-01

    The existence of persistent midlatitude atmospheric regimes, such as blocking events, with time scales larger than 5-10 days and indications of preferred transition paths between them motivates the development of early-warning indicators of regime transitions. Here, we use a barotropic model of the northern midlatitudes winter flow to study such meta-stable regimes. We look at estimates of transfer operators acting on densities evolving on a reduced phase space spanned by the first Empirical Orthogonal Functions of the streamfunction and develop an early-warning indicator of zonal to blocked flow transition. The study of the spectra of transfer operators estimated for different lags reveals a multi-level structure in the flow as well as the effect of memory on the reduced dynamics due to past interactions between the resolved and unresolved variables. The slowest motions in the reduced phase space are thereby found to have time scales larger than 8 days and to behave as Markovian for larger lags. These motions are associated with meta-stable regimes and their transitions and can be detected as almost-invariant sets of the transfer operator. The early-warning indicator is based on the action on an initial density of products of the transfer operators estimated for sufficiently long lags, making use of the semi-group property of these operators and shows relatively good Peirce skill score. From the energy budget of the model, we are able to explain the meta-stability of the regimes and the existence of preferred transition paths as the manifestation of barotropic instability. Finally, even though the model is highly simplified, the skill of the early warning indicator is promising, suggesting that the transfer operator approach can be used in parallel to an operational deterministic model for stochastic prediction or to assess forecast uncertainty.

  13. Detecting regime shifts in the ocean: Data considerations [review article

    deYoung, B.; Harris, R.; Alheit, J.; Beaugrand, G.; Mantua, N.; Shannon, L.

    2004-02-01

    We review observational data sets that have been used to detect regime shifts in the ocean. Through exploration of data time series we develop a definition of a regime shift from a pragmatic perspective, in which a shift is considered as an abrupt change from a quantifiable ecosystem state. We conclude that such changes represent a restructuring of the ecosystem state in some substantial sense that persists for long enough that a new quasi-equilibrium state can be observed. The abruptness of the shift is relative to the life-scale or the reproductive time-scale of the higher predators that are influenced by the shift. In general, the event-forcing is external to the biological ecosystem, usually the physical climate system, but we also identify shifts that can be ascribed to anthropogenic forcing, in our examples fishing. This pragmatic definition allows for several different types of regime shift ranging from simple biogeographic shifts to non-linear state changes. In practice it is quite difficult to determine whether observed changes in an oceanic ecosystem are primarily spatial or temporally regulated. The determination of ecosystem state remains an unresolved, and imprecise, oceanographic problem. We review observations and interpretation from several different oceanic regions as examples to illustrate this pragmatic definition of a regime shift: the Northeast Pacific, the Northwest and Northeast Atlantic, and Eastern Boundary Currents. For each region, different types of data (biological and physical) are available for differing periods of time, and we conclude, with varying degrees of certainty, whether a regime shift is in fact detectable in the data.

  14. Evaluating the Welfare Effects of International Bankruptcy Regimes in a Political Economy Model

    Burcu Eyigungor; Satyajit Chatterjee

    2013-01-01

    We evaluate the welfare benefits of international bankruptcy regimes in a political economy model of debt and default. We show that the socially optimal bankruptcy regime is likely to feature lower restructuring costs than the politically optimal bankruptcy regime. To the extent the current regime reflects the political preferences of borrowing countries, a case can be made for an international bankruptcy regime aimed at reducing (but not eliminating) restructuring costs.

  15. Numerical simulation of flows from free molecular regime to continuum regime by a DVM with streaming and collision processes

    Yang, L. M.; Shu, C.; Wu, J.; Wang, Y.

    2016-02-01

    A discrete velocity method (DVM) with streaming and collision processes is presented in this work for simulation of flows from free molecular regime to continuum regime. The present scheme can be considered as a semi-Lagrangian like scheme. At first, we follow the conventional DVM to discretize the phase velocity space by a number of discrete velocities. Then, for each discrete velocity, the kinetic equation with BGK-Shakhov model is integrated in space and time within one time step. As a result, a simple algebraic formulation can be obtained, and its solution can be marched in time by the streaming and collision processes. However, differently from the conventional semi-Lagrangian scheme, the present scheme uses the MUSCL approach with van Albada limiter in the process of reconstructing the distribution function at the surrounding points of the cell center, and the transport distance is controlled in order to avoid extrapolation. This makes the present scheme be capable of simulating the hypersonic rarefied flows. In addition, as compared to the unified gas kinetic scheme (UGKS), the present scheme is simpler and easier for implementation. Thus, the computational efficiency can be improved accordingly. To validate the proposed numerical scheme, test examples from free molecular regime to continuum regime are simulated. Numerical results showed that the present scheme can predict the flow properties accurately even for hypersonic rarefied flows.

  16. Exchange Rate Regimes – A periodical overview and a critical analysis of exchange rate regimes in Kosovo

    Flamur Bunjaku

    2015-03-01

    Full Text Available Exchange rate regimes and the monetary policy are the key instruments governments use to achieve their economic and financial objectives. Moreover, due to global financial crisis the latter instruments get more importance. Empirical evidences show that exchange rate regimes in Kosovo and its monetary policy throughout their development were mainly influenced by different political and historical developments. In regard of Euroisation of monetary system in Kosovo it was found that this action generated macro - financial stability in terms of inflation and price fluctuation. However, in terms of microeconomic aspects, the unilateral adaptation of Euro as the official currency of Kosovo failed to provide microeconomic advantages such as to export stimulation, and so forth. The main exchange rate regime systems were discussed focusing in their advantages and disadvantages, and it was concluded that there is no commonly accepted theory regarding the optimality of exchange rate regimes. In addition, the global financial crisis impact in the financial system of Kosovo is also discussed and it was found that negative impacts of global financial crisis were moderate and indirect.

  17. Film thickness measurements in liquid–liquid slug flow regimes

    Highlights: • A direct measure of film thickness in liquid–liquid flows was taken. • A region of constant film thickness is presents in slugs where LD⁎⩾1.86. • Experimental data shows the dependency of film thickness on Capillary number. • Expressions are presented to predict the magnitude of the film. -- Abstract: At present there is significant interest in the development of small scale medical diagnostic equipment. These devices offer faster processing times and require smaller sample volumes than equivalent macro scale systems. Although significant attention has been focused upon their outputs, little attention has been devoted to the detailed fluid mechanics that govern the flow mechanisms within these devices. Conventionally, the samples in these small scale devices are segmented into distinct discrete droplets or slugs which are suspended in an organic carrier phase. Separating these slugs from the channel wall is a very thin film of the organic carrier phase. The magnitude of this film is the focus of the present study and the effects of sample slug length and carrier phase fluidic properties on the film are examined over a range of Capillary numbers. A non-intrusive optical technique was used to capture images of the flow from which the magnitude of the film was determined. The experimental results show that the film is not constant along the length of the slug; however above a threshold value for slug length, a region of constant film thickness exists. When compared with existing correlations in the literature, the experimental data showed reasonable agreement with the Bretherton model when the Capillary number was calculated based on the mean two phase flow velocity. However, significant differences were observed when the Capillary number was redefined to account for the mean velocity at the liquid interface, i.e., the mean slug velocity. Analysis of the experimental data revealed that it fell into two distinct flow regimes; a visco

  18. Regime Interpretation of Anomalous Vortex Dynamics in 2D Superconductors

    Low-frequency dynamic impedance [σ-1(ω,T)≡(σ1+iσ2)-1] measurements on Josephson junction arrays found that σ1∼|lnω|, σ2∼const. This implies anomalously sluggish vortex mobilities μV(ω)∼σ-11, and is in conflict with general dynamical scaling expressions. We calculate (a) σ(ω,T) by real-space vortex scaling and (b) μV(ω) using Mori close-quote s formalism for a screened Coulomb gas. We find, in addition to the usual critical (large-ω) and hydrodynamic (low-ω) regimes, a new intermediate-frequency scaling regime into which the experimental data fall. This resolves the above mentioned conflict and makes explicit predictions for the scaling form of σ(ω,T). copyright 1997 The American Physical Society

  19. Quantum Theory as a Critical Regime of Language Dynamics

    Grinbaum, Alexei

    2015-10-01

    Some mathematical theories in physics justify their explanatory superiority over earlier formalisms by the clarity of their postulates. In particular, axiomatic reconstructions drive home the importance of the composition rule and the continuity assumption as two pillars of quantum theory. Our approach sits on these pillars and combines new mathematics with a testable prediction. If the observer is defined by a limit on string complexity, information dynamics leads to an emergent continuous model in the critical regime. Restricting it to a family of binary codes describing `bipartite systems,' we find strong evidence of an upper bound on bipartite correlations equal to 2.82537. This is measurably different from the Tsirelson bound. The Hilbert space formalism emerges from this mathematical investigation as an effective description of a fundamental discrete theory in the critical regime.

  20. Biphoton spectroscopy in a strongly nondegenerate regime of SPDC

    The absorption spectrum of Cr3+ ions in Al2O3 crystal in the range from 691 nm to 697 nm was measured at the room temperature using the biphoton light generated by nondegenerate spontaneous parametric down-conversion of the He-Cd laser radiation (325 nm) in the LiIO3 crystal. The spectrum of the sample was measured by counting the coincidences when signal photons go through the impurity crystal, whilst the wavelength of the idler photons is resolved by a monochromator. A strongly nondegenerate regime of SPDC, when the difference in frequencies of correlated photons exceeds significantly their spectral width, was used in the biphoton spectroscopy for the first time. Such a regime allows one to obtain an absorption spectrum by measuring the wavelength in a completely different spectral range

  1. Biphoton spectroscopy in a strongly nondegenerate regime of SPDC

    Kalachev, A. A.; Kalashnikov, D. A.; Kalinkin, A. A.; Mitrofanova, T. G.; Shkalikov, A. V.; Samartsev, V. V.

    2008-08-01

    The absorption spectrum of Cr3+ ions in Al2O3 crystal in the range from 691 nm to 697 nm was measured at the room temperature using the biphoton light generated by nondegenerate spontaneous parametric down-conversion of the He-Cd laser radiation (325 nm) in the LiIO3 crystal. The spectrum of the sample was measured by counting the coincidences when signal photons go through the impurity crystal, whilst the wavelength of the idler photons is resolved by a monochromator. A strongly nondegenerate regime of SPDC, when the difference in frequencies of correlated photons exceeds significantly their spectral width, was used in the biphoton spectroscopy for the first time. Such a regime allows one to obtain an absorption spectrum by measuring the wavelength in a completely different spectral range.

  2. Heavy ion acceleration in the Breakout Afterburner regime

    Petrov, G M; Thomas, A G R; Krushelnick, K; Beg, F N

    2015-01-01

    Theoretical study of heavy ion acceleration from an ultrathin (20 nm) gold foil irradiated by sub-picosecond lasers is presented. Using two dimensional particle-in-cell simulations we identified two highly efficient ion acceleration schemes. By varying the laser pulse duration we observed a transition from Radiation Pressure Acceleration to the Breakout Afterburner regime akin to light ions. The underlying physics and ion acceleration regimes are similar to that of light ions, however, nuances of the acceleration process make the acceleration of heavy ions more challenging. Two laser systems are studied in detail: the Texas Petawatt Laser and the Trident laser, the former having pulse duration 180 fs, intermediate between very short femtosecond pulses and picosecond pulses. Both laser systems generated directional gold ions beams (~10 degrees half-angle) with fluxes in excess of 1011 ion/sr and normalized energy >10 MeV/nucleon.

  3. Educational differentials in disability vary across and within welfare regimes

    Cambois, Emmanuelle; Solé-Auró, Aïda; Brønnum-Hansen, Henrik;

    2016-01-01

    BACKGROUND: Social differentials in disability prevalence exist in all European countries, but their scale varies markedly. To improve understanding of this variation, the article focuses on each end of the social gradient. It compares the extent of the higher disability prevalence in low social...... groups (referred to as disability disadvantage) and of the lower prevalence in high social groups (disability advantage); country-specific advantages/disadvantages are discussed regarding the possible influence of welfare regimes. METHODS: Cross-sectional disability prevalence is measured by longstanding...... and Germany (youngest age-band). There were notable differences within welfare regime groups. CONCLUSIONS: The country-specific disability advantages/disadvantages across educational groups identified here could help to identify determining factors and the efficiency of national policies implemented to tackle...

  4. The case for regime-based water quality standards

    Poole, Geoffrey C.; Dunham, J.B.; Keenan, D.M.; Sauter, S.T.; McCullough, D.A.; Mebane, Christopher; Lockwood, Jeffrey C.; Essig, Don A.; Hicks, Mark P.; Sturdevant, Debra J.; Materna, E.J.; Spalding, M.; Risley, John; Deppman, Marianne

    2004-01-01

    Conventional water quality standards have been successful in reducing the concentration of toxic substances in US waters. However, conventional standards are based on simple thresholds and are therefore poorly structured to address human-caused imbalances in dynamic, natural water quality parameters, such as nutrients, sediment, and temperature. A more applicable type of water quality standarda??a a??regime standarda??a??would describe desirable distributions of conditions over space and time within a stream network. By mandating the protection and restoration of the aquatic ecosystem dynamics that are required to support beneficial uses in streams, well-designed regime standards would facilitate more effective strategies for management of natural water quality parameters.

  5. A Cold-Strontium Laser in the Superradiant Crossover Regime

    Norcia, Matthew A

    2015-01-01

    Recent proposals suggest that lasers based on narrow dipole-forbidden transitions in cold alkaline earth atoms could achieve linewidths that are orders of magnitude smaller than linewidths of any existing lasers. Here, we demonstrate a laser based on the 7.5 kHz linewidth dipole forbidden $^3 $P$_1$ to $^1 $S$_0$ transition in laser-cooled and tightly confined $^{88}$Sr. We can operate this laser in the bad-cavity regime, where coherence is primarily stored in the atoms, or continuously tune to the more conventional good-cavity regime, where coherence is primarily stored in the light field. We show that the cold-atom gain medium can be repumped to achieve quasi steady-state lasing, and demonstrate up to an order of magnitude suppression in the sensitivity of laser frequency to changes in cavity length, the primary limitation for the most frequency stable lasers today.

  6. A Cold-Strontium Laser in the Superradiant Crossover Regime

    Norcia, Matthew; Thompson, James

    2016-05-01

    We demonstrate and study a laser based on the 7.5 kHz linewidth dipole forbidden 3 P1 to 1 S0 transition in laser-cooled and tightly confined 88 Sr. We can operate this laser in the bad-cavity or superradiant regime, where coherence is primarily stored in the atoms, or continuously tune to the more conventional good-cavity regime, where coherence is primarily stored in the light field. We show that the cold-atom gain medium can be repumped to achieve quasi steady-state lasing. We also demonstrate up to an order of magnitude suppression in the sensitivity of laser frequency to changes in cavity length, verifying a key feature of proposed narrow linewidth lasers based on dipole-forbidden transitions in alkaline earth atoms.

  7. The superradiant instability regime of the spinning Kerr black hole

    Hod, Shahar

    2016-01-01

    Spinning Kerr black holes are known to be superradiantly unstable to massive scalar perturbations. We here prove that the instability regime of the composed Kerr-black-hole-massive-scalar-field system is bounded from above by the dimensionless inequality $M\\mu < m \\cdot \\sqrt{{{2(1+\\gamma) (1-\\sqrt{1-\\gamma^2}) - \\gamma^2} \\over {4\\gamma^2}}}$, where $\\{\\mu,m\\}$ are respectively the proper mass and azimuthal harmonic index of the scalar field and $\\gamma\\equiv r_-/r_+$ is the dimensionless ratio between the horizon radii of the black hole. It is further shown that this {\\it analytically} derived upper bound on the superradiant instability regime of the spinning Kerr black hole agrees with recent {\\it numerical} computations of the instability resonance spectrum.

  8. A new climate regime in northeast pacific ecosystems

    Peterson, William T.; Schwing, Franklin B.

    2003-09-01

    Following a strong El Niño, the climate of the North Pacific underwent a rapid and striking transition in late 1998. Upwelling-favorable winds strengthened over the California Current (CC), and winds weakened in the Gulf of Alaska (GOA). Coastal waters of the CC and GOA cooled by several degrees, and the Pacific Decadal Oscillation (PDO) reversed sign and remained negative through summer 2002. Zooplankton biomass in the northern CC doubled and switched from warm to cold water species dominance, coho and chinook salmon stocks rebounded, and anchovy and osmeriids increased. Persistent changes in atmosphere and upper ocean fields and ecosystem structure suggest a climate regime shift has occurred, similar (opposite) to shifts observed in 1947 (1925 and 1976). If the 1998 regime shift in the northern CC is completely analogous to earlier shifts, then ecosystem structure should have changed in the GOA. Recent surveys indicate this ecosystem has transformed as well.

  9. Onset of the nonlinear regime in unified dark matter models

    We discuss the onset of the nonlinear regime in the context of unified dark matter models involving a generalized Chaplygin gas. We show that the transition from dark-matter-like to dark-energy-like behavior will never be smooth. In some regions of space the transition will never take place while in others it may happen sooner or later than naively expected. As a result the linear theory used in previous studies may break down late in the matter dominated era even on large cosmological scales. We study the importance of this effect showing that its magnitude depends on the exact form of the equation of state in the low density regime. We expect that our results will be relevant for other unified dark matter scenarios, particularly those where the quartessence candidate is a perfect fluid

  10. Regime shifts limit the predictability of land-system change

    Müller, Daniel; Sun, Zhanli; Vongvisouk, Thoumthone;

    2014-01-01

    and abrupt change that invalidate predictions calibrated on past trends. Rapid land-system change can occur when critical thresholds in broad-scale underlying drivers such as commodity prices and climate conditions are crossed or when sudden events such as political change or natural disasters punctuate long...... (China, Laos, Vietnam and Indonesia). The results show how sudden events and gradual changes in underlying drivers caused rapid, surprising and widespread land-system changes, including shifts to different regimes in China, Vietnam and Indonesia, whereas land systems in Laos remained stable in the study...... period but show recent signs of rapid change. The observed regime shifts were difficult to anticipate, which compromises the validity of predictions of future land-system changes and the assessment of their impact on greenhouse gas emissions, hydrological processes, agriculture, biodiversity...

  11. Giant magnetoresistance in the variable-range hopping regime

    Ioffe, L. B.; Spivak, B. Z.

    2013-09-01

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field.

  12. Giant magnetoresistance in the variable-range hopping regime

    Ioffe, L. B., E-mail: ioffe@physics.rutgers.edu [Universite Pierre et Marie Curie, LPTHE (France); Spivak, B. Z. [University of Washington, Department of Physics (United States)

    2013-09-15

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field.

  13. Giant magnetoresistance in the variable-range hopping regime

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field

  14. Multifractal regime transition in a modified minority game model

    The search for more realistic modeling of financial time series reveals several stylized facts of real markets. In this work we focus on the multifractal properties found in price and index signals. Although the usual minority game (MG) models do not exhibit multifractality, we study here one of its variants that does. We show that the nonsynchronous MG models in the nonergodic phase is multifractal and in this sense, together with other stylized facts, constitute a better modeling tool. Using the structure function (SF) approach we detected the stationary and the scaling range of the time series generated by the MG model and, from the linear (non-linear) behavior of the SF we identified the fractal (multifractal) regimes. Finally, using the wavelet transform modulus maxima (WTMM) technique we obtained its multifractal spectrum width for different dynamical regimes.

  15. Adult learning, education, and the labour market inthe employability regime

    Staffan Nilsson

    2013-10-01

    Full Text Available The purpose of this paper is to draw on the research and scholarly literature to explorethe changing discourses and perspectives concerning adult learning, education, and thelabour market in the employability regime. The focus of the nalysis is a Nordic context.The dominant employability regime maintains a technical-rational perspective onlearning and employability. Education is predominantly regarded as an instrumentalpreparation for the labour market. The future demands of the labour market are largelyunknown, however, and vocational and professional training may not provide sufficientpreparation for the increasing complexities of work. Theoretical discussions have beendominated by an alleged mismatch between individual competence and thequalifications that are required in the world of work. There is no consensus regardinghow the gap should be described, explained, or bridged. New demands on educationaldesign have emerged, and ideas related to liberal education and ‘bildung’ have beenreinserted into the political agenda, offering general preparation for a wider array ofchallenges.

  16. Computer Language Choices in Arms Control and Nonproliferation Regimes

    White, G K

    2005-06-10

    The U.S. and Russian Federation continue to make substantive progress in the arms control and nonproliferation transparency regimes. We are moving toward an implementation choice for creating radiation measurement systems that are transparent in both their design and in their implementation. In particular, the choice of a programming language to write software for such regimes can decrease or significantly increase the costs of authentication. In this paper, we compare procedural languages with object-oriented languages. In particular, we examine the C and C++ languages; we compare language features, code generation, implementation details, and executable size and demonstrate how these attributes aid or hinder authentication and backdoor threats. We show that programs in lower level, procedural languages are more easily authenticated than are object-oriented ones. Potential tools and methods for authentication are covered. Possible mitigations are suggested for using object-oriented programming languages.

  17. Dynamic two state stochastic models for ecological regime shifts

    Møller, Jan Kloppenborg; Carstensen, Niels Jacob; Madsen, Henrik; Andersen, Tom

    2009-01-01

    A simple non-linear stochastic two state, discrete-time model is presented. The interaction between benthic and pelagic vegetation in aquatic ecosystems subject to changing external nutrient loading is described by the nonlinear functions. The dynamical behavior of the deterministic part of the...... regimes, depending on how the noise propagates through the system. The dynamical properties of a system should therefore be described through propagation of the state distributions rather than the state means and consequently, stochastic models should be compared in a probabilistic framework....... model illustrates that hysteresis effect and regime shifts can be obtained for a limited range of parameter values only. The effect of multiplicative noise components entering at different levels of the model is presented and discussed. Including noise leads to very different results on the stability of...

  18. Types of runoff regime; 1 : 2 000 000

    Three basic areas with identical runoff regime, i. e. with the same prevailing source supplying the surface streams and distribution of runoff over the year, are defined on the basis of analysis of the mean monthly runoffs, atmospheric precipitation, and air temperature for the period of 1931 - 1980. The runoff regime of the surface streams of the Slovak Republic reveals the altitude zonality, that is, with the increasing sea level altitude the amount of water of the stream increases, the share of the snow precipitation increases, the occurrence of the highest mean monthly discharges moves from March to May - June and that of the lowest from September to January - February. Basic hydrological characteristics as well as distribution of the runoff over the year are presented. (authors)

  19. Onset of the Asymptotic Regime for Finite Orders

    Henson, Joe; Sorkin, Rafael D; Surya, Sumati

    2015-01-01

    We describe a Markov-Chain-Monte-Carlo algorithm which can be used to generate naturally labeled n-element posets at random with a probability distribution of one's choice. Implementing this algorithm for the uniform distribution, we explore the approach to the asymptotic regime in which almost every poset takes on the three-layer structure described by Kleitman and Rothschild (KR). By tracking the n-dependence of several order-invariants, among them the height of the poset, we observe an oscillatory behavior which is very unlike a monotonic approach to the KR regime. Only around n=40 or so does this "finite size dance" appear to give way to a gradual crossover to asymptopia which lasts until n=85, the largest n we have simulated.

  20. Mechanical surface treatment of steel-Optimization parameters of regime

    Laouar, L.; Hamadache, H.; Saad, S.; Bouchelaghem, A.; Mekhilef, S.

    2009-11-01

    Mechanical treatment process by superficial plastic deformation is employed for finished mechanical part surface. It introduces structural modifications that offer to basic material new properties witch give a high quality of physical and geometrical on superficial layers. This study focuses on the application of burnishing treatment (ball burnishing) on XC48 steel and parameters optimisation of treatment regime. Three important parameters were considered: burnishing force ' Py', burnishing feed 'f' and ball radius 'r'. An empirical model has been developed to illustrate the relationship between these parameters and superficial layer characteristics defined by surface roughness ' Ra' and superficial hardness ' Hv'. A program was developed in order to determine the optimum treatment regimes for each characteristic.

  1. Is the Economic Crisis Challenging the Prevailing Gender Regime?

    Leschke, Janine; Jepsen, Maria

    2014-01-01

    This paper addresses the question of whether the current economic and financial crisis is challenging the prevailing gender-equality model in four European countries: Denmark, Germany, Slovakia, and the United Kingdom. After situating the countries in relation to the underlying gender regime and...... analysing the corresponding position of women and men in paid and unpaid work, the paper contains an in-depth discussion of the short- and medium-term policy responses to the crisis. Our analysis shows that independent of the prevailing gender regime, scant public attention has been directed to gender......-sensitive policy responses. These shortcomings are compounded by the observation that the downturn seems to be delaying progress on equality policies....

  2. Accretion to a Magnetized Neutron Star in the "Propeller" Regime

    Toropina, O D; Lovelace, R V E

    2006-01-01

    We investigate spherical accretion to a rotating magnetized star in the "propeller" regime using axisymmetric resistive magnetohydrodynamic simulations. The regime is predicted to occur if the magnetospheric radius is larger than the corotation radius and smaller than the light cylinder radius. The simulations show that accreting matter is expelled from the equatorial region of the magnetosphere and that it moves away from the star in a supersonic, disk-shaped outflow. At larger radial distances the outflow slows down and becomes subsonic. The equatorial matter outflow is initially driven by the centrifugal force, but at larger distances the pressure gradient force becomes significant. We find the fraction of the Bondi accretion rate which accretes to the surface of the star.

  3. Automatic Classification of Offshore Wind Regimes With Weather Radar Observations

    Trombe, Pierre-Julien; Pinson, Pierre; Madsen, Henrik

    2014-01-01

    Weather radar observations are called to play an important role in offshore wind energy. In particular, they can enable the monitoring of weather conditions in the vicinity of large-scale offshore wind farms and thereby notify the arrival of precipitation systems associated with severe wind...... and amplitude) using reflectivity observations from a single weather radar system. A categorical sequence of most likely wind regimes is estimated from a wind speed time series by combining a Markov-Switching model and a global decoding technique, the Viterbi algorithm. In parallel, attributes of precipitation...... systems are extracted from weather radar images. These attributes describe the global intensity, spatial continuity and motion of precipitation echoes on the images. Finally, a CART classification tree is used to find the broad relationships between precipitation attributes and wind regimes...

  4. CHALLENGES FOR ADOPTING INFLATION TARGETING REGIME IN EGYPT

    Awad, Ibrahim

    2013-01-01

    This study intends to investigate challenges facing the CBE for adopting IT regime. Through exploiting the experience of Czech Republic, Poland, and Brazil in the early days of their adopting IT the study underscores the following challenges; (i) A more active role to be played by the CBE is needed to convince decision-making circuits inside the government for the adoption of IT. (ii) The CBE should be factually independent. (iii) Coordination between monetary policy and fiscal policy should ...

  5. The hydrological regime of a forested tropical Andean catchment

    Clark, K. E.; Torres, M. A.; West, A.J.; R. G. Hilton; New, M; Horwath, A. B.; J. B. Fisher; Rapp, J. M.; A. Robles Caceres; Y. Malhi

    2014-01-01

    The hydrology of tropical mountain catchments plays a central role in ecological function, geochemical and biogeochemical cycles, erosion and sediment production, and water supply in globally important environments. There have been few studies quantifying the seasonal and annual water budgets in the montane tropics, particularly in cloud forests. We investigated the water balance and hydrologic regime of the Kosñipata catchment (basin area: 164.4 km2) over the period 2010–20...

  6. Capacity of Fading Channels in the Low Power Regime

    Benkhelifa, Fatma

    2013-01-01

    The low power regime has attracted various researchers in the information theory and communication communities to understand the performance limits of wireless systems. Indeed, the energy consumption is becoming one of the major limiting factors in wireless systems. As such, energy-efficient wireless systems are of major importance to the next generation wireless systems designers. The capacity is a metric that measures the performance limit of a wireless system. The study of the ergodic capacity of some fading channels in the low power regime is the main subject of this thesis. In our study, we consider that the receiver has always a full knowledge of the channel state information. However, we assume that the transmitter has possibly imperfect knowledge of the channel state information, i.e. he knows either perfectly the channel or only an estimated version of the channel. Both radio frequency and free space optical communication channel models are considered. The main contribution of this work is the explicit characterization of how the capacity scales as function of the signal-to-noise ratio in the low power regime. This allows us to characterize the gain due to the perfect knowledge compared to no knowledge of the channel state information at the transmitter. In particular, we show that the gain increases logarithmically for radio frequency communication. However, the gain increases as log2(Pavg) or log4(Pavg) for free-space optical communication, where Pavg is the average power constraint imposed to the input. Furthermore, we characterize the capacity of cascaded fading channels and we applied the result to Rayleigh-product fading channel and to a free-space optical link over gamma-gamma atmospheric turbulence in the presence of pointing errors. Finally, we study the capacity of Nakagami-m fading channel under quality of service constraints, namely the effective capacity. We have shown that the effective capacity converges to Shannon capacity in the very low

  7. Toward a Common Tax Regime for the European Union Countries

    Konstantinos Liapis; Antonios Rovolis; Christos Galanos

    2012-01-01

    The tax burden on wages, profits, property, and goods or services has a serious impact on cross-country competiveness, something that, in turn, impinges strongly on the actual economy of common markets such as the European Union (EU). While the mobility of productive factors is directly related with country tax-regime differences, government budget funding from tax revenues and rates are the main fiscal policy tools. This article analyzes the trends, similarities and differences between the t...

  8. Goods and Services Tax Regime - And Its Challenges.

    I.Bhanu Murthy

    2012-09-01

    Full Text Available In Budget, speech 2010, Finance Minister stated that the country will be moving to the Goods and Services regime by 1st April 2011. The responsibility of preparing the road map for introduction of GST had been entrusted to the Empowered Committee. This paper analyzes the practical problems in implementation of GST. One should consider the various practical difficulties in proper implementation of GST. Some of the important aspects which needs to be considered for effective implementation of GSTin India.

  9. International arbitration and its exclusion from the Brussels regime

    Hamed Alavi

    2016-06-01

    Full Text Available The Brussels regime, which regulates the matters of transnational litigation excludes arbitration from its scope. Upon formation of the Brussels regime the existing instruments concerning arbitration - the United Nations Convention on Recognition and Enforcement of Foreign Arbitral Awards and the 1961 European Convention on International Commercial Arbitration - were believed to be sufficient. The original Brussels Convention 1968 on recognition and enforcement of judgments delivered in the courts of the EU Member States expressly provided for the exclusion of arbitration. The following Brussels I Regulation followed the trend and reinforced the exclusion of arbitration from their material scopes. The rationale for doing so was primarily the prevention of parallel proceedings and irreconcilable judgments. The arbitration exclusion from the Brussels regime has caused a fair amount of confusion, especially regarding the extent and limits of the exclusion. That is, whether the arbitration agreement, the arbitral award and its consequences are covered by the exclusion or they may fall under the scope of the Brussels regulation if they constitute only an incidental question to the main cause of action? The confusion was illustrated in the ECJ judgment West Tankers, which generated negative feedback from the arbitration community and indicated the need for reform. The recently adopted Recast Regulation took it upon itself to clarify the relationship between arbitration and the EU regime of transnational litigation. The exclusion is reinforced ye again and its boundaries are specified in the Preamble. However, whether or not the concerns about the extent and objectives of arbitration exclusion have been at present eliminated, remains to be seen.

  10. Die politische Führung des Milosevic-Regimes

    Hoppe, Hans-Joachim

    1999-01-01

    'Das aus Serbien und Montenegro bestehende 'Restjugoslawien', offiziell die Bundesrepublik Jugoslawien, ist im Balkanraum der einzige Staat, in dem sich seit der Wende von 1989/90 die Kommunisten bis heute an der Macht hielten. Das seit 1987 existierende Milosevic-Regime konzedierte zwar gemäß dem Trend der Zeit einen begrenzten Parlamentarismus und Pluralismus, verstärkte jedoch seinen Repressionsapparat gegen die konkurrierenden Parteien und Organisationen sowie gegen die ethnischen Minderh...

  11. Performance of different tomato cultivars under organic and inorganic regimes

    To study the performance of different tomato cultivars under organic and inorganic regimes an experiment was conducted at New Developmental Farm, The University of Agriculture, Peshawar, Pakistan during the summer 2013-14. The experiment was laid out in RCBD with split plot arrangement having four replications. Organic regimes (FYM, poultry manure and mushroom compost) and inorganic (NPK) regimes were allotted to main plot, while cultivars (Roma VF, Roma, Super Classic, Bambino and Rio Grande) were subjected to sub plots. Organic and Inorganic regimes significantly (P ≤ 0.01) influenced all the studied attributes of tomato cultivars. Among different cultivars, Roma gave maximum plant survival (93.8 percentage), number of leaves plant (84.1), number of flower inflorescence (5.4), number of fruits inflorescence (4.3), number of fruit plant (25.4), fruit size (63.9 cm) fruit weight plant (9.1 kg) and total yield (22.9 t ha). However, it was closely followed by cultivar Rio Grande for number of leaves plant (79.6), number of flower inflorescence (5.1), number of fruits inflorescence (4.0) and number of fruits plant (24.9). Cultivar Super Classic produced minimum number of leaves plant (67.7), flower inflorescence (4.8), fruit size (60.6 cm), fruit weight plant (8.6 kg) and total yield (21.7 t ha). Similarly, highest plant survival (90.0 percentage), number of flower inflorescence (5.1), number of fruits inflorescence (4.0), number of fruit plant (25.4), fruit size (62.4 ml), fruit weight plant (8.90 kg) and total yield (22.9 t ha) were recorded in plants provided with organic conditions Roma cultivar performed better than other cultivars under the agro climatic condition of Peshawar followed by cultivar Rio Grande. Therefore, organic tomato production, and these two cultivars are recommended to be grown in Peshawar area. (author)

  12. Practical stability and instability of regime-switching diffusions

    G.George YIN; Bo ZHANG; Chao ZHU

    2008-01-01

    This work is devoted to practical stability of a class of regime-switching diffusions.First,the notion of practical stability is introduced.Then,sufficient conditions for practical stability and practical instability in probability and in pth mean are provided using a Lyapunov function argument.In addition,easily verifiable conditions on drift and diffusion coefficients are also given.Moreover,examples are supplied for demonstration purposes.

  13. An optimal learning method for developing personalized treatment regimes

    Wang, Yingfei; Powell, Warren

    2016-01-01

    A treatment regime is a function that maps individual patient information to a recommended treatment, hence explicitly incorporating the heterogeneity in need for treatment across individuals. Patient responses are dichotomous and can be predicted through an unknown relationship that depends on the patient information and the selected treatment. The goal is to find the treatments that lead to the best patient responses on average. Each experiment is expensive, forcing us to learn the most fro...

  14. Regime-switching models to study psychological process

    Hamaker, E.L.; Grasman, R.P.P.P.; Kamphuis, J.H.

    2010-01-01

    Many psychological processes are characterized by recurrent shifts between different states. To model these processes at the level of the individual, regime-switching models may prove useful. In this chapter we discuss two of these models: the threshold autoregressive model and the Markov switching autoregressive model. We discuss their main features, and propose estimation methods that can handle missing data. We apply these models to daily affect measurements of an individual diagnosed with...

  15. MATTERS ON THE LEGAL REGIME OF EMPLOYEES’ INDIVIDUAL PERFORMANCE OBJECTIVES

    Radu Stefan Patru

    2012-01-01

    Law 40/2011 brought significant changes to the work relations by the reorientation of certain labour law institutions on the one hand, and by the introduction of legal institutions that have never existed in the Romanian law system until the introduction of this law. Among the significant developments introduced by Law 40/2011, the employees' individual performance objectives will be hereby analysed in terms of the legal regime and of the issues occurring with their applicability for employees.

  16. Brazil, the United States, and the missile technology control regime

    Tollefson, Scott D.

    1990-01-01

    This technical report analyzes Brazil's development of ballistic missiles in light of U.S. pressures to stifle that development. The first section describes and critiques the Missile Technology Control Regime (MTCR); the second analyzes the U.S. application of MTCR guidelines toward Brazil; the third assesses Brazil's ballistic missile capabilities; and the fourth considers Brazil's response. The report concludes that the U.S. policy of restricting space and missile technology to Brazil under...

  17. Customary versus Civil Law within Old Regime France

    Le Bris, David

    2013-01-01

    Law and finance theory emphasizes the negative consequences of civil law on financial and, subsequently, economic development. Before the Revolution, French territory was strictly divided according to the legal regime. Since the Middle-Ages, the southern part of France was under Justinian civil law and the north was under customary laws which, as with common law, gave more flexibility to judges and less right to the state. This dichotomy offers the unique opportunity to test the law and finan...

  18. MCNP/X TRANSPORT IN THE TABULAR REGIME

    HUGHES, H. GRADY [Los Alamos National Laboratory

    2007-01-08

    The authors review the transport capabilities of the MCNP and MCNPX Monte Carlo codes in the energy regimes in which tabular transport data are available. Giving special attention to neutron tables, they emphasize the measures taken to improve the treatment of a variety of difficult aspects of the transport problem, including unresolved resonances, thermal issues, and the availability of suitable cross sections sets. They also briefly touch on the current situation in regard to photon, electron, and proton transport tables.

  19. Conduit flow experiments help constraining the regime of explosive eruptions

    Dellino, P.; Università di Bari; Dioguardi, F.; Università di Bari; Zimanowski, B.; University of Wurzburg; Buttner, R.; University of Wurzburg; Mele, D.; Università di Bari; La Volpe, L.; Università di Bari; Sulpizio, R.; Università di Bari, Centro Interdipartimentale per il Rischio Sismico e Vulcanico, c/o Dip.to Geomineralogico; Doronzo, D. M.; Università di Bari; Sonder, I.; University of Wurzburg; Bonasia, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Calvari, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; Marotta, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia

    2009-01-01

    It is currently impractical to measure what happens in a volcano during an explosive eruption, and up to now much of our knowledge depends on theoretical models. Here we show, by means of large-scale experiments, that the regime of explosive events can be constrained based on the characteristics of magma at the point of fragmentation and conduit geometry. Our model, whose results are consistent with the literature, is a simple tool for defining the conditions at conduit exit th...

  20. Modeling whistler wave generation regimes in magnetospheric cyclotron maser

    D. L. Pasmanik; A. G. Demekhov; V. Y. Trakhtengerts; M. Parrot

    2004-01-01

    Numerical analysis of the model for cyclotron instability in the Earth's magnetosphere is performed. This model, based on the self-consistent set of equations of quasi-linear plasma theory, describes different regimes of wave generation and related energetic particle precipitation. As the source of free energy the injection of energetic electrons with transverse anisotropic distribution function to the interaction region is considered. A parametric study of the model is performed. The ma...