Thermal stratification in sodium. Proceedings of an International Atomic Energy Agency specialists' meeting

Energy Technology Data Exchange (ETDEWEB)

Costa, J [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Grenoble, Grenoble (France)

1983-07-01

The purpose of the meeting was to discuss and exchange views on thermal stratification existing in sodium of the main vessel, secondary circuits and large components of LMFBRs under various operating conditions. The meeting was divided into four sessions: national position presentations; fundamental studies on theory and application of stratification problems, numerical and experimental investigations applied to stratified flow phenomena; computer codes for evaluation of thermal stratification; applied studies covering the computer codes and experimental studies for prediction of temperature velocity field.

Thermal stratification in sodium. Proceedings of an International Atomic Energy Agency specialists' meeting

International Nuclear Information System (INIS)

Costa, J.

1983-07-01

The purpose of the meeting was to discuss and exchange views on thermal stratification existing in sodium of the main vessel, secondary circuits and large components of LMFBRs under various operating conditions. The meeting was divided into four sessions: national position presentations; fundamental studies on theory and application of stratification problems, numerical and experimental investigations applied to stratified flow phenomena; computer codes for evaluation of thermal stratification; applied studies covering the computer codes and experimental studies for prediction of temperature velocity field

Asymptomatic internal carotid artery stenosis and cerebrovascular risk stratification

DEFF Research Database (Denmark)

Nicolaides, Andrew N; Kakkos, Stavros K; Kyriacou, Efthyvoulos

2010-01-01

The purpose of this study was to determine the cerebrovascular risk stratification potential of baseline degree of stenosis, clinical features, and ultrasonic plaque characteristics in patients with asymptomatic internal carotid artery (ICA) stenosis.......The purpose of this study was to determine the cerebrovascular risk stratification potential of baseline degree of stenosis, clinical features, and ultrasonic plaque characteristics in patients with asymptomatic internal carotid artery (ICA) stenosis....

Experimental studies on the thermal stratification and its influence on BLEVEs

Energy Technology Data Exchange (ETDEWEB)

Lin, Wensheng; Gong, Yanwu; Gao, Ting; Gu, Anzhong; Lu, Xuesheng [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200240 (China)

2010-10-15

The thermal stratification of Liquefied Petroleum Gas (LPG) and its effect on the occurrence of the boiling liquid expanding vapor explosion (BLEVE) have been investigated experimentally. Stratifications in liquid and vapor occur when the LPG tank is heated. The degree of the liquid stratification {beta} increases with an increasing heat flux and decreasing filling ratio. The effect of stratification on the BLEVE has been examined with depressurization tests of LPG. The results show that the pressure recovery for the stratified LPG ({beta} = 1.4) upon sudden depressurization is much lower than that for the isothermal LPG ({beta} = 1). It can be concluded that the liquid stratification decreases the liquid energy and the occurrence of the BLEVE. (author)

Cold stratification, but not stratification in salinity, enhances seedling ...

African Journals Online (AJOL)

use

2011-10-26

Oct 26, 2011 ... Cold stratification was reported to release seed dormancy and enhance plant tolerance to salt stress. ... Key words: Cold stratification, salt stress, seedling emergence, ... methods used to cope with salinity, seed pre-sowing.

INLET STRATIFICATION DEVICE

DEFF Research Database (Denmark)

2006-01-01

An inlet stratification device (5) for a circuit circulating a fluid through a tank (1 ) and for providing and maintaining stratification of the fluid in the tank (1 ). The stratification de- vice (5) is arranged vertically in the tank (1) and comprises an inlet pipe (6) being at least partially...... formed of a flexible porous material and having an inlet (19) and outlets formed of the pores of the porous material. The stratification device (5) further comprises at least one outer pipe (7) surrounding the inlet pipe (6) in spaced relationship thereto and being at least partially formed of a porous...

Representing Reservoir Stratification in Land Surface and Earth System Models

Science.gov (United States)

Yigzaw, W.; Li, H. Y.; Leung, L. R.; Hejazi, M. I.; Voisin, N.; Payn, R. A.; Demissie, Y.

2017-12-01

A one-dimensional reservoir stratification modeling has been developed as part of Model for Scale Adaptive River Transport (MOSART), which is the river transport model used in the Accelerated Climate Modeling for Energy (ACME) and Community Earth System Model (CESM). Reservoirs play an important role in modulating the dynamic water, energy and biogeochemical cycles in the riverine system through nutrient sequestration and stratification. However, most earth system models include lake models that assume a simplified geometry featuring a constant depth and a constant surface area. As reservoir geometry has important effects on thermal stratification, we developed a new algorithm for deriving generic, stratified area-elevation-storage relationships that are applicable at regional and global scales using data from Global Reservoir and Dam database (GRanD). This new reservoir geometry dataset is then used to support the development of a reservoir stratification module within MOSART. The mixing of layers (energy and mass) in the reservoir is driven by eddy diffusion, vertical advection, and reservoir inflow and outflow. Upstream inflow into a reservoir is treated as an additional source/sink of energy, while downstream outflow represented a sink. Hourly atmospheric forcing from North American Land Assimilation System (NLDAS) Phase II and simulated daily runoff by ACME land component are used as inputs for the model over the contiguous United States for simulations between 2001-2010. The model is validated using selected observed temperature profile data in a number of reservoirs that are subject to various levels of regulation. The reservoir stratification module completes the representation of riverine mass and heat transfer in earth system models, which is a major step towards quantitative understanding of human influences on the terrestrial hydrological, ecological and biogeochemical cycles.

Manipulation of resonant tunneling by substrate-induced inhomogeneous energy band gaps in graphene with square superlattice potentials

International Nuclear Information System (INIS)

Li, Guanqiang; Chen, Guangde; Peng, Ping; Cao, Zhenzhou; Ye, Honggang

2013-01-01

We investigate the resonant transmission of Dirac electrons through inhomogeneous band gap graphene with square superlattice potentials by transfer matrix method. The effects of the incident angle of the electrons, Fermi energy and substrate-induced Dirac gaps on the transmission are considered. It is found that the Dirac gap of graphene adds another degree of freedom with respect to the incident angle, the Fermi energy and the parameters of periodic superlattice potentials (i.e., the number, width and height of the barriers) for the transmission. In particular, the inhomogeneous Dirac gap induced by staggered substrates can be used to manipulate the transmission. The properties of the conductance and Fano factor at the resonant peaks are found to be affected by the gaps significantly. The results may be helpful for the practical application of graphene-based electronic devices

A new stratification of mourning dove call-count routes

Science.gov (United States)

Blankenship, L.H.; Humphrey, A.B.; MacDonald, D.

1971-01-01

The mourning dove (Zenaidura macroura) call-count survey is a nationwide audio-census of breeding mourning doves. Recent analyses of the call-count routes have utilized a stratification based upon physiographic regions of the United States. An analysis of 5 years of call-count data, based upon stratification using potential natural vegetation, has demonstrated that this uew stratification results in strata with greater homogeneity than the physiographic strata, provides lower error variance, and hence generates greatet precision in the analysis without an increase in call-count routes. Error variance was reduced approximately 30 percent for the contiguous United States. This indicates that future analysis based upon the new stratification will result in an increased ability to detect significant year-to-year changes.

The Effect of Barotropic and Baroclinic Tides on Coastal Stratification and Mixing

Science.gov (United States)

Suanda, S. H.; Feddersen, F.; Kumar, N.

2017-12-01

The effects of barotropic and baroclinic tides on subtidal stratification and vertical mixing are examined with high-resolution, three-dimensional numerical simulations of the Central Californian coastal upwelling region. A base simulation with realistic atmospheric and regional-scale boundary forcing but no tides (NT) is compared to two simulations with the addition of predominantly barotropic local tides (LT) and with combined barotropic and remotely generated, baroclinic tides (WT) with ≈ 100 W m-1 onshore baroclinic energy flux. During a 10 day period of coastal upwelling when the domain volume-averaged temperature is similar in all three simulations, LT has little difference in subtidal temperature and stratification compared to NT. In contrast, the addition of remote baroclinic tides (WT) reduces the subtidal continental shelf stratification up to 50% relative to NT. Idealized simulations to isolate barotropic and baroclinic effects demonstrate that within a parameter space of typical U.S. West Coast continental shelf slopes, barotropic tidal currents, incident energy flux, and subtidal stratification, the dissipating baroclinic tide destroys stratification an order of magnitude faster than barotropic tides. In WT, the modeled vertical temperature diffusivity at the top (base) of the bottom (surface) boundary layer is increased up to 20 times relative to NT. Therefore, the width of the inner-shelf (region of surface and bottom boundary layer overlap) is increased approximately 4 times relative to NT. The change in stratification due to dissipating baroclinic tides is comparable to the magnitude of the observed seasonal cycle of stratification.

Experimental investigation of thermal de-stratification in rock bed TES systems for high temperature applications

International Nuclear Information System (INIS)

Okello, Denis; Nydal, Ole J.; Banda, Eldad J.K.

2014-01-01

Highlights: • High thermal stratifications exists rock bed TES when charge with high temperature heat. • Faster thermal degradation occurs in highly stratified bed irrespective of the bed length. • Average rate of heat loss as a function of storage time increases with increasing average bed temperature. - Abstract: Solar energy fluctuates so much that it cannot promote continuous use. Integration of Thermal Energy Storage (TES) with solar energy collection devices has the potential of making solar energy available on demand. Thermal energy can be stored in a bed of rocks at temperatures suitable for applications like cooking, boiling space heating, etc. During charging, temperature stratification is observed in the bed. In a stratified system, if the heat is used immediately, then it is possible to extract heat at reasonably high temperature from the top. For cases where the system is to be used after sometime (later at night or the following morning), the high temperature heat at the top is observed to degrade as the system tries to establish thermal equilibrium irrespective of the bed height. The average rate of heat loss from the TES unit to the ambient is found to increase with increasing average bed temperatures

Patient characteristics and stratification in medical treatment studies for metastatic colorectal cancer: a proposal for standardization of patient characteristic reporting and stratification.

Science.gov (United States)

Sorbye, H; Köhne, C-H; Sargent, D J; Glimelius, B

2007-10-01

Prognostic factors have the potential to determine the survival of patients to a greater extent than current antineoplastic agents. Despite this knowledge, there is no consensus on, first, what patient characteristics to report and, second, what stratification factors to use in metastatic colorectal cancer trials. Seven leading oncology and medical journals were reviewed for phase II and III publications reporting on medical treatment of metastatic colorectal cancer patients during 2001-2005. One hundred and forty-three studies with 21 214 patients were identified. The reporting of patient characteristics and use of stratification was noted. Age, gender, performance status, metastases location, sites and adjuvant chemotherapy were often reported (99-63%). Laboratory values as alkaline phosphatase, lactate dehydrogenase and white blood cell count, repeatedly found to be of prognostic relevance, were rarely reported (5-9%). Stratification was used in all phase III trials; however, only study centre was used with any consistency. There is considerable inconsistency in the reporting of patient characteristics and use of stratification factors in metastatic colorectal cancer trials. We propose a standardization of patient characteristics reporting and stratification factors. A common set of characteristics and strata will aid in trial reporting, interpretation and future meta-analyses.

Stratification-induced order--disorder phase transitions in molecularly thin confined films

International Nuclear Information System (INIS)

Schoen, M.; Diestler, D.J.; Cushman, J.H.

1994-01-01

By means of grand canonical ensemble Monte Carlo simulations of a monatomic film confined between unstructured (i.e., molecularly smooth) rigidly fixed solid surfaces (i.e., walls), we investigate the mechanism of molecular stratification, i.e., the tendency of atoms to arrange themselves in layers parallel with the walls. Stratification is accompanied by a heretofore unnoticed order--disorder phase transition manifested as a maximum in density fluctuations at the transition point. The transition involves phases with different transverse packing characteristics, although the number of layers accommodated between the walls remains unchanged during the transition, which occurs periodically as the film thickens. However, with increasing thickness, an increasingly smaller proportion of the film is structurally affected by the transition. Thus, the associated maximum in density fluctuations diminishes rapidly with film thickness

Numerical solution of chemically reactive non-Newtonian fluid flow: Dual stratification

Science.gov (United States)

Rehman, Khalil Ur; Malik, M. Y.; Khan, Abid Ali; Zehra, Iffat; Zahri, Mostafa; Tahir, M.

2017-12-01

We have found that only a few attempts are available in the literature relatively to the tangent hyperbolic fluid flow induced by stretching cylindrical surfaces. In particular, temperature and concentration stratification effects have not been investigated until now with respect to the tangent hyperbolic fluid model. Therefore, we have considered the tangent hyperbolic fluid flow induced by an acutely inclined cylindrical surface in the presence of both temperature and concentration stratification effects. To be more specific, the fluid flow is attained with the no slip condition, which implies that the bulk motion of the fluid particles is the same as the stretching velocity of a cylindrical surface. Additionally, the flow field situation is manifested with heat generation, mixed convection and chemical reaction effects. The flow partial differential equations give a complete description of the present problem. Therefore, to trace out the solution, a set of suitable transformations is introduced to convert these equations into ordinary differential equations. In addition, a self-coded computational algorithm is executed to inspect the numerical solution of these reduced equations. The effect logs of the involved parameters are provided graphically. Furthermore, the variations of the physical quantities are examined and given with the aid of tables. It is observed that the fluid temperature is a decreasing function of the thermal stratification parameter and a similar trend is noticed for the concentration via the solutal stratification parameter.

Germination and development of pecan cultivar seedlings by seed stratification

Directory of Open Access Journals (Sweden)

Igor Poletto

2015-12-01

Full Text Available Abstract: The objective of this work was to evaluate the effect of seed stratification on germination rate, germination speed, and initial development of seedlings of six pecan (Carya illinoinensis cultivars under subtropical climatic conditions in southern Brazil. For stratification, the seeds were placed in boxes with moist sand, in a cold chamber at 4°C, for 90 days. In the fourteenth week after sowing, the emergence speed index, total emergence, plant height, stem diameter, and number of leaves were evaluated. Seed stratification significantly improves the germination potential and morphological traits of the evaluated cultivars.

Temperature Stratification in a Cryogenic Fuel Tank

Science.gov (United States)

Daigle, Matthew John; Smelyanskiy, Vadim; Boschee, Jacob; Foygel, Michael Gregory

2013-01-01

A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It accounts for cryogenic propellant loading, storage, and unloading in the conditions of normal, increased, and micro- gravity. The model involves multiple horizontal control volumes in both liquid and ullage spaces. Temperature and velocity boundary layers at the tank walls are taken into account by using correlation relations. Heat exchange involving the tank wall is considered by means of the lumped-parameter method. By employing basic conservation laws, the model takes into consideration the major multi-phase mass and energy exchange processes involved, such as condensation-evaporation of the hydrogen, as well as flows of hydrogen liquid and vapor in the presence of pressurizing helium gas. The model involves a liquid hydrogen feed line and a tank ullage vent valve for pressure control. The temperature stratification effects are investigated, including in the presence of vent valve oscillations. A simulation of temperature stratification effects in a generic cryogenic tank has been implemented in Matlab and results are presented for various tank conditions.

Experiments and numerical simulations of fluctuating thermal stratification in a branch pipe

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Akira; Murase, Michio; Sasaki, Toru [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan); Takenaka, Nobuyuki; Hamatani, Daisuke [Kobe Univ. (Japan)

2002-09-01

Many pipes branch off from the main pipe in plants. When the main flow in the main pipe is hotter than a branch pipe that branches off downward, the hot water penetrates into the branch pipe with the cavity flow that is induced by the main flow and causes thermal stratification. If the interface of the stratification fluctuates in an occluded branch pipe, thermal fatigue may occur in pipe wall. Some experiments and numerical simulations were conducted to elucidate the mechanism of this fluctuating thermal stratification. The vortex structures were observed in the experiments of straight or bent branch pipes. When the main flow was heated and the thermal stratification interface was at the elbow, a ''burst'' phenomenon occurred in the interface in connection with large heat fluctuation. The effects of pipe shape on the length of penetration were investigated in order to modify simulation conditions. The vortex structures and the fluctuating thermal stratification at elbow in the numerical simulation showed good agreement with experiments. (author)

Theoretical potential for low energy consumption phase change memory utilizing electrostatically-induced structural phase transitions in 2D materials

Science.gov (United States)

Rehn, Daniel A.; Li, Yao; Pop, Eric; Reed, Evan J.

2018-01-01

Structural phase-change materials are of great importance for applications in information storage devices. Thermally driven structural phase transitions are employed in phase-change memory to achieve lower programming voltages and potentially lower energy consumption than mainstream nonvolatile memory technologies. However, the waste heat generated by such thermal mechanisms is often not optimized, and could present a limiting factor to widespread use. The potential for electrostatically driven structural phase transitions has recently been predicted and subsequently reported in some two-dimensional materials, providing an athermal mechanism to dynamically control properties of these materials in a nonvolatile fashion while achieving potentially lower energy consumption. In this work, we employ DFT-based calculations to make theoretical comparisons of the energy required to drive electrostatically-induced and thermally-induced phase transitions. Determining theoretical limits in monolayer MoTe2 and thin films of Ge2Sb2Te5, we find that the energy consumption per unit volume of the electrostatically driven phase transition in monolayer MoTe2 at room temperature is 9% of the adiabatic lower limit of the thermally driven phase transition in Ge2Sb2Te5. Furthermore, experimentally reported phase change energy consumption of Ge2Sb2Te5 is 100-10,000 times larger than the adiabatic lower limit due to waste heat flow out of the material, leaving the possibility for energy consumption in monolayer MoTe2-based devices to be orders of magnitude smaller than Ge2Sb2Te5-based devices.

Probing potential energy curves of C2- by translational energy spectrometry

International Nuclear Information System (INIS)

Gupta, A.K.; Aravind, G.; Krishnamurthy, M.

2004-01-01

We present studies on collision induced dissociation of C 2 - with Ar at an impact energy of 15 keV. The C - fragment ion kinetic-energy release (KER) distribution is measured and is used to compute the KER in the center of mass (c.m.) frame (KER c.m. ). We employ the reflection method to deduce an effective repulsive potential-energy curve for the molecular anion that is otherwise difficult to evaluate from quantum computational methods. The nuclear wave packet of the molecular ion in the initial ground state is computed by the semiclassical WKB method using the potential-energy curve of the 2 Σ g + ground electronic state calculated by an ab initio quantum computation method. The ground-state nuclear wave packet is reflected on a parametrized repulsive potential-energy curve where the parameters are determined by fitting the measured KER c.m. with the calculated KER distribution

Cancer Stratification by Molecular Imaging

Directory of Open Access Journals (Sweden)

Justus Weber

2015-03-01

Full Text Available The lack of specificity of traditional cytotoxic drugs has triggered the development of anticancer agents that selectively address specific molecular targets. An intrinsic property of these specialized drugs is their limited applicability for specific patient subgroups. Consequently, the generation of information about tumor characteristics is the key to exploit the potential of these drugs. Currently, cancer stratification relies on three approaches: Gene expression analysis and cancer proteomics, immunohistochemistry and molecular imaging. In order to enable the precise localization of functionally expressed targets, molecular imaging combines highly selective biomarkers and intense signal sources. Thus, cancer stratification and localization are performed simultaneously. Many cancer types are characterized by altered receptor expression, such as somatostatin receptors, folate receptors or Her2 (human epidermal growth factor receptor 2. Similar correlations are also known for a multitude of transporters, such as glucose transporters, amino acid transporters or hNIS (human sodium iodide symporter, as well as cell specific proteins, such as the prostate specific membrane antigen, integrins, and CD20. This review provides a comprehensive description of the methods, targets and agents used in molecular imaging, to outline their application for cancer stratification. Emphasis is placed on radiotracers which are used to identify altered expression patterns of cancer associated markers.

Numerical analysis of stratification and destratification processes in a tidally energetic inlet with an ebb tidal delta

NARCIS (Netherlands)

Purkiani, K.; Becherer, J.; Flöser, G.; Gräwe, U.; Mohrholz, V.; Schuttelaars, H.M.; Burchard, H.

2015-01-01

Stratification and destratification processes in a tidally energetic, weakly stratified inlet in the Wadden Sea (south eastern North Sea) are investigated in this modeling study. Observations of current velocity and vertical density structure show strain-induced periodic stratification for the

Transient thermal stresses and stress intensity factors induced by thermal stratification in feedwater lines

International Nuclear Information System (INIS)

Sanchez Sarmiento, G.; Pardo, E.

1985-01-01

General analytical solutions for the thermal stresses and circumferential crack propagation in piping branches of nuclear power plants, that connect two circuits of the same fluid at different temperatures, are presented in this paper. Under certain conditions, two regions of the fluid possessing both temperatures with a separating layer of small thickness are formed ('flow stratification'). Dimensionless analytical expressions for the steady state temperature distribution in the pipe wall and the corresponding thermal stress are here derived, in terms of the basic geometrical and physical parameters. The position and thickness of the separating layer are considered as data of the model. Stress intensity ranges at any point of the tube wall are then determined. Finally, thermally induced stress intensity factors are calculated for hipothetically inside surface cracks. (orig.)

Vertical Stratification Engineering for Organic Bulk-Heterojunction Devices.

Science.gov (United States)

Huang, Liqiang; Wang, Gang; Zhou, Weihua; Fu, Boyi; Cheng, Xiaofang; Zhang, Lifu; Yuan, Zhibo; Xiong, Sixing; Zhang, Lin; Xie, Yuanpeng; Zhang, Andong; Zhang, Youdi; Ma, Wei; Li, Weiwei; Zhou, Yinhua; Reichmanis, Elsa; Chen, Yiwang

2018-05-22

High-efficiency organic solar cells (OSCs) can be produced through optimization of component molecular design, coupled with interfacial engineering and control of active layer morphology. However, vertical stratification of the bulk-heterojunction (BHJ), a spontaneous activity that occurs during the drying process, remains an intricate problem yet to be solved. Routes toward regulating the vertical separation profile and evaluating the effects on the final device should be explored to further enhance the performance of OSCs. Herein, we establish a connection between the material surface energy, absorption, and vertical stratification, which can then be linked to photovoltaic conversion characteristics. Through assessing the performance of temporary, artificial vertically stratified layers created by the sequential casting of the individual components to form a multilayered structure, optimal vertical stratification can be achieved. Adjusting the surface energy offset between the substrate results in donor and acceptor stabilization of that stratified layer. Further, a trade-off between the photocurrent generated in the visible region and the amount of donor or acceptor in close proximity to the electrode was observed. Modification of the substrate surface energy was achieved using self-assembled small molecules (SASM), which, in turn, directly impacted the polymer donor to acceptor ratio at the interface. Using three different donor polymers in conjunction with two alternative acceptors in an inverted organic solar cell architecture, the concentration of polymer donor molecules at the ITO (indium tin oxide)/BHJ interface could be increased relative to the acceptor. Appropriate selection of SASM facilitated a synchronized enhancement in external quantum efficiency and power conversion efficiencies over 10.5%.

Numerical investigation of potential stratification caused by a cryogenic helium spill inside a tunnel

Science.gov (United States)

Sinclair, Cameron; Malecha, Ziemowit; Jedrusyna, Artur

2018-04-01

The sudden release of cryogenic fluid into an accelerator tunnel can pose a significant health and safety risk. For this reason, it is important to evaluate the consequences of such a spill. Previous publications concentrated on either Oxygen Deficiency Hazard or the evaluation of mathematical models using experimental data. No studies to date have focussed on the influence of cryogen inlet conditions on flow development. In this paper, the stratification behaviour of low-temperature helium released into an air-filled accelerator tunnel is investigated for varying helium inlet diameters. A numerical model was constructed using the OpenFOAM Toolbox of a generalised 3D geometry, with similar hydraulic characteristics to the CERN and SLAC tunnels. This model has been validated against published experimental and numerical data. A dimensionless parameter, based on Bakke number, was then determined for the onset of stratification, taking into account the helium inlet diameter; a dimensionless parameter for the degree of stratification was also employed. The simulated flow behaviour is described in terms of these dimensionless parameters, as well as the temperature and oxygen concentration at various heights throughout the tunnel.

Polar ocean stratification in a cold climate.

Science.gov (United States)

Sigman, Daniel M; Jaccard, Samuel L; Haug, Gerald H

2004-03-04

The low-latitude ocean is strongly stratified by the warmth of its surface water. As a result, the great volume of the deep ocean has easiest access to the atmosphere through the polar surface ocean. In the modern polar ocean during the winter, the vertical distribution of temperature promotes overturning, with colder water over warmer, while the salinity distribution typically promotes stratification, with fresher water over saltier. However, the sensitivity of seawater density to temperature is reduced as temperature approaches the freezing point, with potential consequences for global ocean circulation under cold climates. Here we present deep-sea records of biogenic opal accumulation and sedimentary nitrogen isotopic composition from the Subarctic North Pacific Ocean and the Southern Ocean. These records indicate that vertical stratification increased in both northern and southern high latitudes 2.7 million years ago, when Northern Hemisphere glaciation intensified in association with global cooling during the late Pliocene epoch. We propose that the cooling caused this increased stratification by weakening the role of temperature in polar ocean density structure so as to reduce its opposition to the stratifying effect of the vertical salinity distribution. The shift towards stratification in the polar ocean 2.7 million years ago may have increased the quantity of carbon dioxide trapped in the abyss, amplifying the global cooling.

Dynamic modeling of stratification for chilled water storage tank

International Nuclear Information System (INIS)

Osman, Kahar; Al Khaireed, Syed Muhammad Nasrul; Ariffin, Mohd Kamal; Senawi, Mohd Yusoff

2008-01-01

Air conditioning of buildings can be costly and energy consuming. Application of thermal energy storage (TES) reduces cost and energy consumption. The efficiency of the overall operation is affected by storage tank sizing design, which affects thermal stratification of water during charging and discharging processes in TES system. In this study, numerical simulation is used to determine the relationship between tank size and good thermal stratification. Three dimensional simulations with different tank height-to-diameter ratio (HD) and inlet Reynolds number (Re) are investigated. The effect of the number of diffuser holes is also studied. For shallow tanks (low HD) simulations, no acceptable thermocline thickness can be seen for all Re experimented. Partial mixing is observed throughout the process. Medium HD tanks simulations show good thermocline behavior and clear distinction between warm and cold water can be seen. Finally, deep tanks (high HD) show less acceptable thermocline thickness as compared to that of medium HD tanks. From this study, doubling and halving the number of diffuser holes show no significant effect on the thermocline behavior

On Optimum Stratification

OpenAIRE

M. G. M. Khan; V. D. Prasad; D. K. Rao

2014-01-01

In this manuscript, we discuss the problem of determining the optimum stratification of a study (or main) variable based on the auxiliary variable that follows a uniform distribution. If the stratification of survey variable is made using the auxiliary variable it may lead to substantial gains in precision of the estimates. This problem is formulated as a Nonlinear Programming Problem (NLPP), which turn out to multistage decision problem and is solved using dynamic programming technique.

Principal stratification in causal inference.

Science.gov (United States)

Frangakis, Constantine E; Rubin, Donald B

2002-03-01

Many scientific problems require that treatment comparisons be adjusted for posttreatment variables, but the estimands underlying standard methods are not causal effects. To address this deficiency, we propose a general framework for comparing treatments adjusting for posttreatment variables that yields principal effects based on principal stratification. Principal stratification with respect to a posttreatment variable is a cross-classification of subjects defined by the joint potential values of that posttreatment variable tinder each of the treatments being compared. Principal effects are causal effects within a principal stratum. The key property of principal strata is that they are not affected by treatment assignment and therefore can be used just as any pretreatment covariate. such as age category. As a result, the central property of our principal effects is that they are always causal effects and do not suffer from the complications of standard posttreatment-adjusted estimands. We discuss briefly that such principal causal effects are the link between three recent applications with adjustment for posttreatment variables: (i) treatment noncompliance, (ii) missing outcomes (dropout) following treatment noncompliance. and (iii) censoring by death. We then attack the problem of surrogate or biomarker endpoints, where we show, using principal causal effects, that all current definitions of surrogacy, even when perfectly true, do not generally have the desired interpretation as causal effects of treatment on outcome. We go on to forrmulate estimands based on principal stratification and principal causal effects and show their superiority.

Determining the core stratification in white dwarfs with asteroseismology

Directory of Open Access Journals (Sweden)

Charpinet S.

2017-01-01

Full Text Available Using the forward modeling approach and a new parameterization for the core chemical stratification in ZZ Ceti stars, we test several situations typical of the usually limited constraints available, such as small numbers of observed independent modes, to carry out asteroseismology of these stars. We find that, even with a limited number of modes, the core chemical stratification (in particular, the location of the steep chemical transitions expected in the oxygen profile can be determined quite precisely due to the significant sensitivity of some confined modes to partial reflexion (trapping effects. These effects are similar to the well known trapping induced by the shallower chemical transitions at the edge of the core and at the bottom of the H-rich envelope. We also find that success to unravel the core structure depends on the information content of the available seismic data. In some cases, it may not be possible to isolate a unique, well-defined seismic solution and the problem remains degenerate. Our results establish that constraining the core chemical stratification in white dwarf stars based solely on asteroseismology is possible, an opportunity that we have started to exploit.

Thermal stratification in the pressurizer

International Nuclear Information System (INIS)

Baik, S.J.; Lee, K.W.; Ro, T.S.

2001-01-01

The thermal stratification in the pressurizer due to the insurge from the hot leg to the pressurizer has been studied. The insurge flow of the cold water into the pressurizer takes place during the heatup/cooldown and the normal or abnormal transients during power operation. The pressurizer vessel can undergo significant thermal fatigue usage caused by insurges and outsurges. Two-dimensional axisymmetric transient analysis for the thermal stratification in the pressurizer is performed using the computational fluid dynamics code, FLUENT, to get the velocity and temperature distribution. Parametric study has been carried out to investigate the effect of the inlet velocity and the temperature difference between the hot leg and the pressurizer on the thermal stratification. The results show that the insurge flow of cold water into the pressurizer does not mix well with hot water, and the cold water remains only in the lower portion of the pressurizer, which leads to the thermal stratification in the pressurizer. The thermal load on the pressurizer due to the thermal stratification or the cyclic thermal transient should be examined with respect to the mechanical integrity and this study can serve the design data for the stress analysis. (authors)

Hot-electron-mediated desorption rates calculated from excited-state potential energy surfaces

DEFF Research Database (Denmark)

Olsen, Thomas; Gavnholt, Jeppe; Schiøtz, Jakob

2009-01-01

We present a model for desorption induced by (multiple) electronic transitions [DIET (DIMET)] based on potential energy surfaces calculated with the delta self-consistent field extension of density-functional theory. We calculate potential energy surfaces of CO and NO molecules adsorbed on variou...

Thermal stratification in a scaled-down suppression pool of the Fukushima Daiichi nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Jo, Byeongnam, E-mail: jo@vis.t.u-tokyo.ac.jp [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan); Erkan, Nejdet [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan); Takahashi, Shinji [Department of Nuclear Engineering and Management, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Song, Daehun [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan); Hyundai and Kia Corporate R& D Division, Hyundai Motors, 772-1, Jangduk-dong, Hwaseong-Si, Gyeonggi-Do 445-706 (Korea, Republic of); Sagawa, Wataru; Okamoto, Koji [Nuclear Professional School, The University of Tokyo, 2-22 Shirakata, Tokai-mura, Ibaraki 319-1188 (Japan)

2016-08-15

Highlights: • Thermal stratification was reproduced in a scaled-down suppression pool of the Fukushima Daiichi nuclear power plants. • Horizontal temperature profiles were uniform in the toroidal suppression pool. • Subcooling-steam flow rate map of thermal stratification was obtained. • Steam bubble-induced flow model in suppression pool was suggested. • Bubble frequency strongly depends on the steam flow rate. - Abstract: Thermal stratification in the suppression pool of the Fukushima Daiichi nuclear power plants was experimentally investigated in sub-atmospheric pressure conditions using a 1/20 scale torus shaped setup. The thermal stratification was reproduced in the scaled-down suppression pool and the effect of the steam flow rate on different thermal stratification behaviors was examined for a wide range of steam flow rates. A sparger-type steam injection pipe that emulated Fukushima Daiichi Unit 3 (F1U3) was used. The steam was injected horizontally through 132 holes. The development (formation and disappearance) of thermal stratification was significantly affected by the steam flow rate. Interestingly, the thermal stratification in the suppression pool vanished when subcooling became lower than approximately 5 °C. This occurred because steam bubbles are not well condensed at low subcooling temperatures; therefore, those bubbles generate significant upward momentum, leading to mixing of the water in the suppression pool.

Proceedings of the specialists meeting on experience with thermal fatigue in LWR piping caused by mixing and stratification

International Nuclear Information System (INIS)

1998-01-01

This specialists meeting on experience with thermal fatigue in LWR piping caused by mixing and stratification, was held in June 1998 in Paris. It included five sessions. Session 1: operating experience (7 papers): Historical perspective; EDF experience with local thermohydraulic phenomena in PWRs: impacts and strategies; Thermal fatigue in safety injection lines of French PWRs: technical problems, regulatory requirements, concerns about other areas; US NRC Regulatory perspective on unanticipated thermal fatigue in LWR piping; Failure to the Residual Heat Removal system suction line pipe in Genkai unit 1 caused by thermal stratification cycling; Emergency Core Cooling System pipe crack incident at Tihange unit 1; Two leakages induced by thermal stratification at the Loviisa power plant). Session 2: thermal hydraulic phenomena (5 papers): Thermal stratification in small pipes with respect to fatigue effects and so called 'Banana effect'; Thermal stratification in the surge line of the Korean next generation reactor; Thermal stratification in horizontal pipes investigated in UPTF-TRAM and HDR facilities; Research on thermal stratification in un-isolable piping of reactor pressure boundary; Thermal mixing phenomena in piping systems: 3D numerical simulation and design considerations. Session 3: response of material and structure (5 papers): Fatigue induced by thermal stratification, Results of tests and calculations of the COUFAST model; Laboratory simulation of thermal fatigue cracking as a basis for verifying life models; Thermo-mechanical analysis methods for the conception and the follow up of components submitted to thermal stratification transients; Piping analysis methods of a PWR surge line for stratified flow; The thermal stratification effect on surge lines, The VVER estimation. Session 4: monitoring aspects (4 papers): Determination of the thermal loadings affecting the auxiliary lines of the reactor coolant system in French PWR plants; Expected and

Multilayer fabric stratification pipes for solar tanks

DEFF Research Database (Denmark)

Andersen, Elsa; Furbo, Simon; Fan, Jianhua

2007-01-01

The thermal performance of solar heating systems is strongly influenced by the thermal stratification in the heat storage. The higher the degree of thermal stratification is, the higher the thermal performance of the solar heating systems. Thermal stratification in water storages can for instance...

Stratification in SNR-300 outlet plenum

International Nuclear Information System (INIS)

Reinders, R.

1983-01-01

In the inner outlet plenum of the SNR-300 under steady state conditions a large toroidal vortex is expected. The main flow passes through the gap between dipplate and shield vessel to the outer annular space. Only 3% of the flow pass the 24 emergency cooling holes, situated in the shield vessel. The sodium leaves the reactor tank through the 3 symmetrically arranged outlet nozzles. For a scram flow rates and temperatures are decreased simultaneously, so it is expected, that stratification occurs in the inner outlet plenum. A measure of stratification effects is the Archimedes Number Ar, which is the relation of buoyancy forces (negative) to kinetic energy. (The Archimedes Number is nearly identical with the Richardson Number). For values Ar>1 stratification can occur. Under the assumption of stratification the code TIRE was developed, which is only applicable for the period of time after some 50 sec after scram. This code serves for long term calculations. As the equations are very simple, it is a very fast code which gives the possibility to calculate transients for some hours real time. This code mainly has to take into account the pressure difference between inner plenum and outlet annulus caused by geodatic pressure. That force is in equilibrium with the pressure drop over the gap and holes in the shield vessel. For more detailed calculations of flow pattern and temperature distribution the code MIX and INKO 2T are applied. MIX was developed and validated at ANL, INKO 2T is a development of INTERATOM. INKO 2T is under validation. Mock up experiments were carried out with water to simulate the transient behavior of the SNR-300 outlet plenum. Calculations obtained by INKO 2T for steady state and the transient are shown for the flow pattern. Results of measurements also prove that stratification begins after about 30 sec. Measurements and detailed calculations show that it is admissible to use the code TIRE for the long term calculations. Calculations for a scram

Talent Complementarity and Organizational Stratification

Science.gov (United States)

Abrahamson, Mark

1973-01-01

Stratification within organizations as produced by the distribution of functional importance among positions is investigated. According to Stinchcombe's hypothesis from the functional theory of stratification, the rewards given to various positions are expected to be less equal when talent is complementary rather than additive. Actual differences…

Experimental and numerical study on density stratification erosion phenomena with a vertical buoyant jet in a small vessel

Energy Technology Data Exchange (ETDEWEB)

Abe, Satoshi, E-mail: abe.satoshi@jaea.go.jp; Ishigaki, Masahiro; Sibamoto, Yasuteru; Yonomoto, Taisuke

2016-07-15

Highlights: • This paper shows results of a small scale experiment and CFD analyses on a density stratification erosion with a vertical buoyant jet. • The particle image velocimetry (PIV) and quadrupole mass spectrometer (QMS) with a multiport rotating valve were applied. • Two typical well-used RANS models were applied. • The simulated stratification erosion was in agreement with the experimental result, which suggested that the turbulence mixing occurred only in the jet impinging region. - Abstract: The Japan Atomic Energy Agency (JAEA) has started the ROSA-SA project to investigate thermal hydraulic phenomena in a reactor containment vessel during a severe accident. The hydrogen distribution in the vessel is one of significant safety issues in discussing a potential of hydrogen combustion in the containment. Density stratification and its break-up are important phenomena affecting the hydrogen distribution. This paper focuses on a density stratification erosion and break-up mechanism with a vertical buoyant jet promoting the turbulent helium transport. Small scale experiment and computational fluid dynamics (CFD) analyses were carried out for investigating this phenomena. In the experiment, a rectangular vessel made with acrylic plates with a width of 1.5 m, a length of 1.5 m and a height of 1.8 m was used for visualizing flow field with particle image velocimetry (PIV) system. The quadrupole mass spectrometer (QMS) system with a multiport rotating valve was applied for measuring gaseous concentration at 20 elevation points. In CFD analysis with OpenFOAM, two typical well-used turbulence models were used: low-Reynolds number type k–ε model and SST k–ω model, with a turbulence model modification to consider the buoyant effect in the stratification. As a result, the stratification erosion in the CFD analyses with the modified turbulence model agreed well with the experimental data, indicating importance of the turbulence damping by the buoyant effect.

Experimental and numerical study on density stratification erosion phenomena with a vertical buoyant jet in a small vessel

International Nuclear Information System (INIS)

Abe, Satoshi; Ishigaki, Masahiro; Sibamoto, Yasuteru; Yonomoto, Taisuke

2016-01-01

Highlights: • This paper shows results of a small scale experiment and CFD analyses on a density stratification erosion with a vertical buoyant jet. • The particle image velocimetry (PIV) and quadrupole mass spectrometer (QMS) with a multiport rotating valve were applied. • Two typical well-used RANS models were applied. • The simulated stratification erosion was in agreement with the experimental result, which suggested that the turbulence mixing occurred only in the jet impinging region. - Abstract: The Japan Atomic Energy Agency (JAEA) has started the ROSA-SA project to investigate thermal hydraulic phenomena in a reactor containment vessel during a severe accident. The hydrogen distribution in the vessel is one of significant safety issues in discussing a potential of hydrogen combustion in the containment. Density stratification and its break-up are important phenomena affecting the hydrogen distribution. This paper focuses on a density stratification erosion and break-up mechanism with a vertical buoyant jet promoting the turbulent helium transport. Small scale experiment and computational fluid dynamics (CFD) analyses were carried out for investigating this phenomena. In the experiment, a rectangular vessel made with acrylic plates with a width of 1.5 m, a length of 1.5 m and a height of 1.8 m was used for visualizing flow field with particle image velocimetry (PIV) system. The quadrupole mass spectrometer (QMS) system with a multiport rotating valve was applied for measuring gaseous concentration at 20 elevation points. In CFD analysis with OpenFOAM, two typical well-used turbulence models were used: low-Reynolds number type k–ε model and SST k–ω model, with a turbulence model modification to consider the buoyant effect in the stratification. As a result, the stratification erosion in the CFD analyses with the modified turbulence model agreed well with the experimental data, indicating importance of the turbulence damping by the buoyant effect.

Tunnel-induced Dipolar Resonances in a Double-well Potential.

Science.gov (United States)

Schulz, Bruno; Saenz, Alejandro

2016-11-18

A system of two dipolar particles that are confined in a double-well potential and interact via a realistic isotropic interaction potential is investigated as a protoype for ultracold atoms with a magnetic dipole moment or ultracold dipolar heteronuclear diatomic molecules in double-well traps or in optical lattices. The resulting energy spectrum is discussed as a function of the dipole-dipole interaction strength. The variation of the strength of the dipole-dipole interaction is found to lead to various resonance phenomena. Among those are the previously discussed inelastic confinement-induced resonances as well as the dipole-induced resonances. It is found that the double-well potential gives rise to a new type of resonances, tunnel-induced dipolar ones. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fundamental Interactions in Gasoline Compression Ignition Engines with Fuel Stratification

Science.gov (United States)

Wolk, Benjamin Matthew

Transportation accounted for 28% of the total U.S. energy demand in 2011, with 93% of U.S. transportation energy coming from petroleum. The large impact of the transportation sector on global climate change necessitates more-efficient, cleaner-burning internal combustion engine operating strategies. One such strategy that has received substantial research attention in the last decade is Homogeneous Charge Compression Ignition (HCCI). Although the efficiency and emissions benefits of HCCI are well established, practical limits on the operating range of HCCI engines have inhibited their application in consumer vehicles. One such limit is at high load, where the pressure rise rate in the combustion chamber becomes excessively large. Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. The aim is to introduce reactivity gradients through fuel stratification to promote sequential auto-ignition rather than a bulk-ignition, as in the homogeneous case. A gasoline-fueled compression ignition engine with fuel stratification is termed a Gasoline Compression Ignition (GCI) engine. Although a reasonable amount of experimental research has been performed for fuel stratification in GCI engines, a clear understanding of how the fundamental in-cylinder processes of fuel spray evaporation, mixing, and heat release contribute to the observed phenomena is lacking. Of particular interest is gasoline's pressure sensitive low-temperature chemistry and how it impacts the sequential auto-ignition of the stratified charge. In order to computationally study GCI with fuel stratification using three-dimensional computational fluid dynamics (CFD) and chemical kinetics, two reduced mechanisms have been developed. The reduced mechanisms were developed from a large, detailed mechanism with about 1400 species for a 4-component gasoline surrogate. The two versions of the reduced mechanism developed in this work are: (1) a 96-species version and (2

A probabilistic topic model for clinical risk stratification from electronic health records.

Science.gov (United States)

Huang, Zhengxing; Dong, Wei; Duan, Huilong

2015-12-01

incorporating risk scoring knowledge as prior information can improve the performance in risk stratification. Experimental results reveal that our models achieve competitive performance in risk stratification in comparison with existing supervised approaches. In addition, the unsupervised nature of our models makes them highly portable to the risk stratification tasks of various diseases. Moreover, patient sub-profiles and sub-profile-specific risk tiers generated by our models are coherent and informative, and provide significant potential to be explored for the further tasks, such as patient cohort analysis. We hypothesize that the proposed framework can readily meet the demand for risk stratification from a large volume of EHRs in an open-ended fashion. Copyright © 2015 Elsevier Inc. All rights reserved.

Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

Directory of Open Access Journals (Sweden)

Hu eWang

2015-08-01

Full Text Available This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors’ group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI combustion, stratification controlled premixed charge compression ignition (PCCI combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fuelled with both high cetane number fuels, such as DME and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition (RCCI/highly premixed charge combustion (HPCC mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

Salinity-induced stratification and the onset of hypoxia during the Holocene Thermal Maximum and the Medieval Climate Anomaly

Science.gov (United States)

Papadomanolaki, Nina; Dijkstra, Nikki; van Helmond, Niels; Sangiorgi, Francesca; Hagens, Mathilde; Kotthoff, Ulrich; Slomp, Caroline

2016-04-01

During the past ~8000 years the Baltic Sea has experienced three distinct intervals of hypoxia, of which the last one is still ongoing. These intervals are characterized by enhanced sedimentary organic matter burial and enrichment of redox-sensitive metals, such as molybdenum and iron. The first two of these intervals occurred during the Holocene Thermal Maximum (HTM) and the Medieval Climate Anomaly (MCA), two phases with high temperatures and changed precipitation patterns. Studies focussing on the Holocene sedimentary record of the Baltic Sea aim at clarifying the causes of the initiation, evolution and termination of these hypoxic intervals, as well as their consequences. This information could help to potentially aid in finding solutions for the mitigation of present-day hypoxia in the Baltic Sea. The factors contributing to hypoxia development during the HTM and MCA are still debated. Here we present data from a core retrieved during Integrated Ocean Drilling Program (IODP) Expedition 347 in the Landsort Deep basin, the deepest basin of the Baltic Sea at 463m water depth. Sediments were analysed at a high resolution using inorganic geochemical and (mainly marine) palynological proxies. Dinoflagellate cyst (dinocyst) assemblages and total elemental compositions provide clues on the role of salinity in enhancing stratification, ultimately causing hypoxia. During the onset of the HTM changes in salinity, as indicated by the palynology, closely follow changes in sedimentary organic carbon burial and trace metal concentrations. This suggests that stratification was an important cause of hypoxia during the HTM. In contrast, the palynology suggests that reduced stratification did not contribute to re-oxygenation during the termination of the HTM. We did not observe major changes in the palynology throughout the hypoxic interval of the MCA. Our results thus suggest that changes in salinity did not cause the onset and termination of hypoxia during the MCA.

CFD modelling of hydrogen stratification in enclosures: Model validation and application to PAR performance

Energy Technology Data Exchange (ETDEWEB)

Hoyes, J.R., E-mail: james.hoyes@hsl.gsi.gov.uk; Ivings, M.J.

2016-12-15

Highlights: • The ability of CFD to predict hydrogen stratification phenomena is investigated. • Contrary to expectation, simulations on tetrahedral meshes under-predict mixing. • Simulations on structured meshes give good agreement with experimental data. • CFD model used to investigate the effects of stratification on PAR performance. • Results show stratification can have a significant effect on PAR performance. - Abstract: Computational Fluid Dynamics (CFD) models are maturing into useful tools for supporting safety analyses. This paper investigates the capabilities of CFD models for predicting hydrogen stratification in a containment vessel using data from the NEA/OECD SETH2 MISTRA experiments. Further simulations are then carried out to illustrate the qualitative effects of hydrogen stratification on the performance of Passive Autocatalytic Recombiner (PAR) units. The MISTRA experiments have well-defined initial and boundary conditions which makes them well suited for use in a validation study. Results are presented for the sensitivity to mesh resolution and mesh type. Whilst the predictions are shown to be largely insensitive to the mesh resolution they are surprisingly sensitive to the mesh type. In particular, tetrahedral meshes are found to induce small unphysical convection currents that result in molecular diffusion and turbulent mixing being under-predicted. This behaviour is not unique to the CFD model used here (ANSYS CFX) and furthermore, it may affect simulations run on other non-aligned meshes (meshes that are not aligned perpendicular to gravity), including non-aligned structured meshes. Following existing best practice guidelines can help to identify potential unphysical predictions, but as an additional precaution consideration should be given to using gravity-aligned meshes for modelling stratified flows. CFD simulations of hydrogen recombination in the Becker Technologies THAI facility are presented with high and low PAR positions

Qinshan phase II extension nuclear power project thermal stratification and fatigue stress analysis for pressurizer surge line

International Nuclear Information System (INIS)

Yu Xiaofei; Zhang Yixiong; Ai Honglei

2010-01-01

Thermal stratification of pressurizer surge line induced by the inside fluid brings on global bending moments, local thermal stresses, unexpected displacements and support loadings of the pipe system. In order to avoid a costly three-dimensional computation, a combined 1D/2D technique has been developed and implemented to analyze the thermal stratification and fatigue stress of pressurize surge line of QINSHAN Phase II Extension Nuclear Power Project in this paper, using the computer codes SYSTUS and ROCOCO. According to the mechanical analysis results of stratification, the maximum stress and cumulative usage factor, the loadings at connections of surge line to main pipe and RCP and the displacements of surge line at supports are obtained. (authors)

Time-dependent stratification in the Gauthami-Godavari Estuary

Digital Repository Service at National Institute of Oceanography (India)

Rao, T.V.N.

. National Academy of Sciences, Washington, D.C. CZITROM, S. P. R. 1986. The effect of river discharge in the re- sidual circulation in the eastern Irish Sea. Continental Shelf Research 6:475–485. DRONKERS,J.AND J. VAN DE KREEKE. 1986. Experimental deter.... Springer- Verlag, New York. SIMPSON, J. H., J. SHARPLES, AND T. P. RIPPETH. 1991. A perspec- tive model of stratification induced by freshwater runoff. Es- tuarine, Coastal and Shelf Science 33:23–35. STOMMEL, H. 1953. Computation of pollution in a...

Analysis of stratification effects on mechanical integrity of pressurizer surge line

International Nuclear Information System (INIS)

Thomas-Solgadi, E.; Taupin, P.; Ensel, C.

1992-01-01

Unexpected thermal movements in pressurizer surge lines have been reported by several PWR operating utilities. Sometimes gaps between pipe and pipe whip restraints can become closed and plastic deformations could result. Moreover these movements, which have not been considered at conception, can induce additional stresses, and design limits on fatigue and stresses may be exceeded. These piping movements are caused by thermal stratification phenomenon in the horizontal part of the surge line (difference of temperature between hot leg and pressurizer varying from 30 C to above 160 C). To assess the mechanical consequences of this 3-dimensional phenomenon, FRAMATOME has developed a computer program using simplified models (1 and 2-dimensional). This method integrates past investigations on thermal-hydraulic variation of the stratification based on plant monitoring programs carried out by FRAMATOME since 1981, and based also on thermal-hydraulic tests and thermal-hydraulic computer code results. The methodology developed by FRAMATOME permits the following calculations: movements of the line in the elastic and plastic domains; stresses (Mises criterion -- calculations in compliance with ASME or RCC-M codes); usage factors in different components (elbows, welds, ...); crack propagation taking into account stratification and plastic shakedown

Thermal Stratification in Vertical Mantle Tanks

DEFF Research Database (Denmark)

Knudsen, Søren; Furbo, Simon

2001-01-01

It is well known that it is important to have a high degree of thermal stratification in the hot water storage tank to achieve a high thermal performance of SDHW systems. This study is concentrated on thermal stratification in vertical mantle tanks. Experiments based on typical operation conditions...... are carried out to investigate how the thermal stratification is affected by different placements of the mantle inlet. The heat transfer between the solar collector fluid in the mantle and the domestic water in the inner tank is analysed by CFD-simulations. Furthermore, the flow pattern in the vertical mantle...

A Comparative Review of Stratification Texts and Readers

Science.gov (United States)

Peoples, Clayton D.

2012-01-01

Social stratification is a core substantive area within sociology. There are a number of textbooks and readers available on the market that deal with this central topic. In this article, I conduct a comparative review of (a) four stratification textbooks and (b) four stratification readers. (Contains 2 tables.)

Effect of sample stratification on dairy GWAS results

Directory of Open Access Journals (Sweden)

Ma Li

2012-10-01

Full Text Available Abstract Background Artificial insemination and genetic selection are major factors contributing to population stratification in dairy cattle. In this study, we analyzed the effect of sample stratification and the effect of stratification correction on results of a dairy genome-wide association study (GWAS. Three methods for stratification correction were used: the efficient mixed-model association expedited (EMMAX method accounting for correlation among all individuals, a generalized least squares (GLS method based on half-sib intraclass correlation, and a principal component analysis (PCA approach. Results Historical pedigree data revealed that the 1,654 contemporary cows in the GWAS were all related when traced through approximately 10–15 generations of ancestors. Genome and phenotype stratifications had a striking overlap with the half-sib structure. A large elite half-sib family of cows contributed to the detection of favorable alleles that had low frequencies in the general population and high frequencies in the elite cows and contributed to the detection of X chromosome effects. All three methods for stratification correction reduced the number of significant effects. EMMAX method had the most severe reduction in the number of significant effects, and the PCA method using 20 principal components and GLS had similar significance levels. Removal of the elite cows from the analysis without using stratification correction removed many effects that were also removed by the three methods for stratification correction, indicating that stratification correction could have removed some true effects due to the elite cows. SNP effects with good consensus between different methods and effect size distributions from USDA’s Holstein genomic evaluation included the DGAT1-NIBP region of BTA14 for production traits, a SNP 45kb upstream from PIGY on BTA6 and two SNPs in NIBP on BTA14 for protein percentage. However, most of these consensus effects had

Enhancement of a Turbulence Sub-Model for More Accurate Predictions of Vertical Stratifications in 3D Coastal and Estuarine Modeling

Directory of Open Access Journals (Sweden)

Wenrui Huang

2010-03-01

Full Text Available This paper presents an improvement of the Mellor and Yamada's 2nd order turbulence model in the Princeton Ocean Model (POM for better predictions of vertical stratifications of salinity in estuaries. The model was evaluated in the strongly stratified estuary, Apalachicola River, Florida, USA. The three-dimensional hydrodynamic model was applied to study the stratified flow and salinity intrusion in the estuary in response to tide, wind, and buoyancy forces. Model tests indicate that model predictions over estimate the stratification when using the default turbulent parameters. Analytic studies of density-induced and wind-induced flows indicate that accurate estimation of vertical eddy viscosity plays an important role in describing vertical profiles. Initial model revision experiments show that the traditional approach of modifying empirical constants in the turbulence model leads to numerical instability. In order to improve the performance of the turbulence model while maintaining numerical stability, a stratification factor was introduced to allow adjustment of the vertical turbulent eddy viscosity and diffusivity. Sensitivity studies indicate that the stratification factor, ranging from 1.0 to 1.2, does not cause numerical instability in Apalachicola River. Model simulations show that increasing the turbulent eddy viscosity by a stratification factor of 1.12 results in an optimal agreement between model predictions and observations in the case study presented in this study. Using the proposed stratification factor provides a useful way for coastal modelers to improve the turbulence model performance in predicting vertical turbulent mixing in stratified estuaries and coastal waters.

Level shifts induced by a short-range potential

International Nuclear Information System (INIS)

Karnakov, B.M.; Mur, V.D.

1984-01-01

Formulas are derived which express the shifts of levels with energies Esub(n)sup((0)) << rsub(c)sup(-2) in a field Vsub(f)(r) induced by a short-range potential U(r) of radius rsub(c) in terms of the low energy scattering parameters (scattering length and effective radius) with a moment l in the potential. If the interaction between the particle and center is nonresonant, the method developed is identical to perturbation theory on the scattering length. The theory is extended to systems with random degeneracy (Vsub(f) is the Coulomb potential). Formulas describing quasi-intersection of terms are obtained for the case of resonance interaction with the center in a partial wave with l not equal to 0 when energetically close levels are present in both U and Vsub(f). Some features of the level shift are mentioned for the case when the level possesses an anomalously small coupling energy and its coresponding wave function becomes delocalized with decrease of the coupling energy to zero. The problem is discussed of the level shift when the potential Vsub(f) is a potential well surrounded by a weaklyt penetrable barrier. Some applications of the theory to a particle in the field of two short-range potentials or in the field of a short-range and Coulomb centers are considered. Formulas are also obtained for the shifts and widths of the Landau levels and of the shallow level with an arbitrary moment which perturbs the Landau levels

Stratification devices

DEFF Research Database (Denmark)

Andersen, Elsa; Furbo, Simon

2008-01-01

Thermal stratification in the storage tank is extremely important in order to achieve high thermal performance of a solar heating system. High temperatures in the top of the storage tank and low temperatures in the bottom of the storage tank lead to the best operation conditions for any solar hea...

Control Carbon to Prevent corium Stratification In-Vessel Retention

Energy Technology Data Exchange (ETDEWEB)

Go, A Ra; Hong, Seung Hyun; Kim, Sang Nyung [Kyung Hee Univ., Yongin (Korea, Republic of)

2013-10-15

As a result, the thermal margin decreases, and the nuclear reactor vessel may be destroyed. To control Carbons, which is the major cause of stratification, Ruthenium and Hafnium are inserted inside the lower reactor head which initiates a chemical reaction with Carbon. SPARTAN program is used to confirm a reaction probability which is measured in bond energy and strength etc. To analyze the possibility of bonding with Carbon, the initial property of Ruthenium and Carbon are measured during the calculated absorbing process. After following that theory, the Spartan program is able to determine if it can insert the metal. After verifying the combination of Ruthenium and Carbon, the Spartan program analyzes the impact of the Carbon to prevent the corium stratification. It determines the possibility of the success with the introduction of the IVR concept. Ruthenium is suitable to Carbon bonding process to decrease affect to corium behavior which do not form stratification. The metal which can combine with Carbon should be satisfied with temperature as high as 2800 .deg. C. Therefore, the further research works are determined by using the Spartan program to calculate the Carbon and Ruthenium bonding energy, and to check other bonding results as follows. After check the results, review this theory to insert the Ruthenium in reactor vessel. APR1400 and OPR1000, Korea Hydro and Nuclear power plant core meltdown accident has been evaluated a high level in severe accident. When the reactor core is melted down, it is stratified into the metal layer and the ceramic layer. As the heat conductivity of metal layer is higher than that of the ceramic layer, heat concentration occurs in the upper part of the bottom hemisphere which comes into contact with the metal layer.

Dynamo Tests for Stratification Below the Core-Mantle Boundary

Science.gov (United States)

Olson, P.; Landeau, M.

2017-12-01

Evidence from seismology, mineral physics, and core dynamics points to a layer with an overall stable stratification in the Earth's outer core, possibly thermal in origin, extending below the core-mantle boundary (CMB) for several hundred kilometers. In contrast, energetic deep mantle convection with elevated heat flux implies locally unstable thermal stratification below the CMB in places, consistent with interpretations of non-dipole geomagnetic field behavior that favor upwelling flows below the CMB. Here, we model the structure of convection and magnetic fields in the core using numerical dynamos with laterally heterogeneous boundary heat flux in order to rationalize this conflicting evidence. Strongly heterogeneous boundary heat flux generates localized convection beneath the CMB that coexists with an overall stable stratification there. Partially stratified dynamos have distinctive time average magnetic field structures. Without stratification or with stratification confined to a thin layer, the octupole component is small and the CMB magnetic field structure includes polar intensity minima. With more extensive stratification, the octupole component is large and the magnetic field structure includes intense patches or high intensity lobes in the polar regions. Comparisons with the time-averaged geomagnetic field are generally favorable for partial stratification in a thin layer but unfavorable for stratification in a thick layer beneath the CMB.

Advantages using inlet stratification devices in solar domestic hot water storage tanks

DEFF Research Database (Denmark)

Dragsted, Janne; Furbo, Simon; Bava, Federico

2017-01-01

performances of two solar domestic hot water systems are presented. One system is a traditional high flow system with a heat exchanger spiral in the tank. The other system is a low flow system with an external heat exchanger and a newly developed inlet stratifier from EyeCular Technologies ApS installed......The thermal performance of a domestic hot water system is strongly affected by whether the storage tank is stratified or not. Thermal stratification can be built up in a solar storage tank if the heated water from the solar collectors enters the tank through an inlet stratifier.Measured thermal...... with the stratification device has a higher thermal performance compared to the system with the heat exchanger spiral inside the tank.The relative performance (defined as the ratio between the net utilized solar energy of the low flow system and the net utilized solar energy of the high flow system), is a function...

Effect of Insulation Thickness on Thermal Stratification in Hot Water Tanks

Directory of Open Access Journals (Sweden)

Burak KURŞUN

2018-03-01

Full Text Available One of the important factors to be considered in increasing the efficiency of hot water storage tanks used for thermal energy storage is thermal stratification. Reducing the temperature of the water at the base of the tank provides more utilization of the energy of the heat source during the heating of the water and improves the efficiency of the system. In this study, the effect of the insulation thickness on the outer surface of the tank and the ratio of the tank diameter to the height (D/H on the thermal stratification was investigated numerically. Numerical analyzes were carried out for the condition that the insulation thickness was constant and variable in the range of D/H=0,3-1. Water was used as the heat storage fluid and the analysis results were obtained for eight hours cooling period. Numerical results showed that the temperature difference between the bottom and top surfaces of the tank increased between 7-9 ° C for the range of D / H = 0,3-1 with changing the insulation thickness.

Fatigue flaw growth assessment and inclusion of stratification to the LBB assessment

Energy Technology Data Exchange (ETDEWEB)

Samohyl, P.

1997-04-01

The application of the LBB requires also fatigue flaw growth assessment. This analysis was performed for PWR nuclear power plants types VVER 440/230, VVER 440/213c, VVER 1000/320. Respecting that these NPP`s were designed according to Russian codes that differ from US codes it was needed to compare these approaches. Comparison with our experimental data was accomplished, too. Margins of applicability of the US methods and their modifications for the materials used for construction of Czech and Slovak NPP`s are shown. Computer code accomplishing the analysis according to described method is presented. Some measurement and calculations show that thermal stratifications in horizontal pipelines can lead to additive loads that are not negligible and can be dangerous. An attempt to include these loads induced by steady-state stratification was made.

The potential of renewable energy

International Nuclear Information System (INIS)

Piot, M.

2007-01-01

This article presents and comments on definitions of the potential of renewable forms of energy and, in a second part, takes a look at the potentials mentioned in the energy perspectives published by the Swiss Federal Office of Energy (SFOE). The following potentials are looked at: technical potential, ecological potential, economic potential, exploitable and expected potentials, technical, economic and ecological expansion potentials, potential of particular technologies in Switzerland, exploitable and expected expansion potential. Four scenarios for expansion potential are briefly described

Long time durability tests of fabric inlet stratification pipes

DEFF Research Database (Denmark)

Andersen, Elsa; Furbo, Simon

2008-01-01

and that this destroys the capability of building up thermal stratification for the fabric inlet stratification pipe. The results also show that although dirt, algae etc. are deposited in the fabric pipes in the space heating tank, the capability of the fabric inlet stratifiers to build up thermal stratification...

A reconceptualization of age stratification in China.

Science.gov (United States)

Yin, P; Lai, K H

1983-09-01

Using the concepts of age stratification theory--age effect, cohort effect, and subcohort differences--this paper provides a new perspective on age stratification in China. Currently, the literature suggests that the status of elderly people declined after the Communist Revolution and will further decline with modernization. We discuss the problems with this perspective and argue, instead, that the status of elderly adults did not decline for the majority of the aged during the Maoist years. Rather, the most important change in the age stratification system during the Maoist years was the change in the criterion of age stratification--from age differences to cohort and subcohort differences. Furthermore, the subcohort of elderly adults who suffered the most status decline during the Maoist years--the bourgeoisie--may actually enjoy an increase in status with the recent modernization impetus. Research suggestions from this new perspective are discussed.

Dynamic Potential Intensity: An improved representation of the ocean’s impact on tropical cyclones

Energy Technology Data Exchange (ETDEWEB)

Balaguru, Karthik; Foltz, Gregory R.; Leung, Lai-Yung; D' Asaro, Eric; Emanuel, Kerry A.; Liu, Hailong; Zedler, Sarah E.

2015-08-18

To incorporate the effects of tropical cyclone (TC)-induced upper ocean mixing and sea surface temperature (SST) cooling on TC intensification, a vertical average of temperature down to a fixed depth was proposed as a replacement for SST within the framework of air-sea coupled Potential Intensity (PI). However, the depth to which TC-induced mixing penetrates may vary substantially with ocean stratification and storm state. To account for these effects, here we develop a “Dynamic Potential Intensity” (DPI) based on considerations of stratified fluid turbulence. For the Argo period 2004–2013 and the three major TC basins of the Northern Hemisphere, we show that the DPI explains 11–32% of the variance in TC intensification, compared to 0–16% using previous methods. The improvement obtained using the DPI is particularly large in the eastern Pacific where the thermocline is shallow and ocean stratification effects are strong.

Various manifestations of stratification phenomenon during intravenous cholangiography

Energy Technology Data Exchange (ETDEWEB)

Tada, S; Nanjo, M; Kino, M; Sekiya, T; Harada, J; Kuroda, T; Anno, I [Jikei Univ., Tokyo (Japan). School of Medicine

1979-07-01

A classification has been made of various types of stratification phenomenon during intravenous cholangiography. The stage of gallbladder opacification in the recumbent position has been classified as (I) mottled, (II) dendritic, (III) ring-like, and (IV) homogeneous. 'Dendritic' type of stratification phenomenon has never been reported in the literature to our knowledge. At 20 min following infusion of contrast material homogeneous opacification of the gallbladder was noticed in only 14% of patients. The others fell into types I, II or III of stratification phenomenon. In contrast, 87% of the opacified gallbladders were homogeneous on the after fatty meal film. It is therefore mandatory for diagnosis that either a 24 h film or a fatty meal film be taken to avoid the stratification phenomenon.

Various manifestations of stratification phenomenon during intravenous cholangiography

International Nuclear Information System (INIS)

Tada, S.; Nanjo, M.; Kino, M.; Sekiya, T.; Harada, J.; Kuroda, T.; Anno, I.

1979-01-01

A classification has been made of various types of stratification phenomenon during intravenous cholangiography. The stage of gallbladder opacification in the recumbent position has been classified as (I) mottled, (II) dendritic, (III) ring-like, and (IV) homogeneous. 'Dendritic' type of stratification phenomenon has never been reported in the literature to our knowledge. At 20 min following infusion of contrast material homogeneous opacification of the gallbladder was noticed in only 14% of patients. The others fell into types I, II or III of stratification phenomenon. In contrast, 87% of the opacified gallbladders were homogeneous on the after fatty meal film. It is therefore mandatory for diagnosis that either a 24 h film or a fatty meal film be taken to avoid the stratification phenomenon. (author)

Modeling Multimodal Stratification

DEFF Research Database (Denmark)

Boeriis, Morten

2017-01-01

. The article outlines a theoretical experiment exploring how an alternative way of modeling stratification and instantiation may raise some interesting ideas on the concepts of realization dynamics, system-instance, and the different contexts of the semiotic text. This is elaborated in a discussion of how...

Evaluation charts of thermal stresses in cylindrical vessels induced by thermal stratification of contained fluid

International Nuclear Information System (INIS)

Furuhashi, Ichiro; Kawasaki, Nobuchika; Kasahara, Naoto

2008-01-01

Temperature and thermal stress in cylindrical vessels were analysed for the thermal stratification of contained fluid. Two kinds of temperature analysis results were obtained such as the exact temperature solution of eigenfunction series and the simple approximate one by the temperature profile method. Furthermore, thermal stress shell solutions were obtained for the simple approximate temperatures. Through comparison with FEM analyses, these solutions were proved to be adequate. The simple temperature solution is described by one parameter that is the temperature decay coefficient. The thermal stress shell solutions are described by two parameters. One is the ratio between the temperature decay coefficient and the load decay coefficient. Another is the nondimensional width of stratification. These solutions are so described by few parameters that those are suitable for the simplified thermal stress evaluation charts. These charts enable quick and accurate thermal stress evaluations of cylindrical vessel of this problem compared with conventional methods. (author)

Evaluation charts of thermal stresses in cylindrical vessels induced by thermal stratification of contained fluid

International Nuclear Information System (INIS)

Furuhashi, Ichiro; Kawasaki, Nobuchika; Kasahara, Naoto

2007-01-01

Temperature and thermal stress in cylindrical vessels were analysed for the thermal stratification of contained fluid. Two kinds of temperature analysis results were obtained such as the exact temperature solution of eigen-function series and the simple approximate one by the temperature profile method. Furthermore, shell solutions of thermal stress were obtained for the simple approximate temperatures. Through comparison with FEM analyses, these solutions were proved to be adequate. The simple temperature solution is described by one parameter that is the temperature decay factor. The shell solutions of thermal stress are described by two parameters. One is the ratio between the temperature decay factor and the local decay factor. Another is the non-dimensional width of stratification. These solution are so described by few parameters that those are suitable for the simplified thermal stress evaluation charts. These charts enable quick and accurate thermal stress evaluations of cylindrical vessel of this problem compared with conventional methods. (author)

The Impact of Internal Wave Seasonality on the Continental Shelf Energy Budget

Science.gov (United States)

Wihsgott, Juliane U.; Sharples, Jonathan; Hopkins, Joanne; Palmer, Matthew R.; Mattias Green, J. A.

2017-04-01

Heating-stirring models are widely used to simulate the timing and strength of stratification in continental shelf environments. Such models are based on bulk potential energy (PE) budgets: the loss of PE due to thermal stratification is balanced by wind and tidal mixing. The model often fails to accurately predict the observed vertical structure, as it only considers forces acting on the surface and bottom boundary of the water column. This highlights the need for additional internal energy sources to close this budget, and produce an accurate seasonal cycle of stratification. We present new results that test the impact of boundary layer and internal wave forcing on stratification and vertical density structure in continental shelves. A new series of continuous measurements of full water depth vertical structure, dynamics and meteorological data spanning 17 months (March'14-July'15) provide unprecedented coverage over a full seasonal cycle at a station 120 km north-east from the continental shelf break. We observe a highly variable but energetic internal wave field from the onset of stratification that suggests a continuous supply of internal PE. The heating-stirring model reproduces bulk characteristics of the seasonal cycle. While it accurately predicts the timing of the onset in spring and peak stratification in late summer there is a persistent 20 J m-3 positive offset between the model and observations throughout this period. By including a source of internal energy in the model we improve the prediction for the strength of stratification and the vertical distribution of heat. Yet a constant source of PE seems to result in a seasonal discrepancy resulting in too little mixing during strong stratification and too much mixing during transient periods. The discrepancy seen in the model is consistent with the seasonality observed in the internal wave field. We will establish the role that changing stratification (N2) exerts on the internal wave field and vice

Energy harvesting by means of flow-induced vibrations on aerospace vehicles

Science.gov (United States)

Li, Daochun; Wu, Yining; Da Ronch, Andrea; Xiang, Jinwu

2016-10-01

This paper reviews the design, implementation, and demonstration of energy harvesting devices that exploit flow-induced vibrations as the main source of energy. Starting with a presentation of various concepts of energy harvesters that are designed to benefit from a general class of flow-induced vibrations, specific attention is then given at those technologies that may offer, today or in the near future, a potential benefit to extend the operational capabilities and to monitor critical parameters of unmanned aerial vehicles. Various phenomena characterized by flow-induced vibrations are discussed, including limit cycle oscillations of plates and wing sections, vortex-induced and galloping oscillations of bluff bodies, vortex-induced vibrations of downstream structures, and atmospheric turbulence and gusts. It was found that linear or linearized modeling approaches are commonly employed to support the design phase of energy harvesters. As a result, highly nonlinear and coupled phenomena that characterize flow-induced vibrations are neglected in the design process. The Authors encourage a shift in the current design paradigm: considering coupled nonlinear phenomena, and adequate modeling tools to support their analysis, from a design limitation to a design opportunity. Special emphasis is placed on identifying designs and implementations applicable to aircraft configurations. Application fields of flow-induced vibrations-based energy harvesters are discussed including power supply for wireless sensor networks and simultaneous energy harvest and control. A large body of work on energy harvesters is included in this review journal. Whereas most of the references claim direct applications to unmanned aerial vehicles, it is apparent that, in most of the cases presented, the working principles and characteristics of the energy harvesters are incompatible with any aerospace applications. Finally, the challenges that hold back the integration of energy harvesting

Exactly solvable energy-dependent potentials

International Nuclear Information System (INIS)

Garcia-Martinez, J.; Garcia-Ravelo, J.; Pena, J.J.; Schulze-Halberg, A.

2009-01-01

We introduce a method for constructing exactly-solvable Schroedinger equations with energy-dependent potentials. Our method is based on converting a general linear differential equation of second order into a Schroedinger equation with energy-dependent potential. Particular examples presented here include harmonic oscillator, Coulomb and Morse potentials with various types of energy dependence.

Optimized endogenous post-stratification in forest inventories

Science.gov (United States)

Paul L. Patterson

2012-01-01

An example of endogenous post-stratification is the use of remote sensing data with a sample of ground data to build a logistic regression model to predict the probability that a plot is forested and using the predicted probabilities to form categories for post-stratification. An optimized endogenous post-stratified estimator of the proportion of forest has been...

Fuel and combustion stratification study of Partially Premixed Combustion

OpenAIRE

Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

2016-01-01

Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a clear definition of “fuel and combustion stratifications” is obvious in literature. Hence, it is difficult to compare stratification levels of different PPC strategies or other combustion concepts. T...

Studies of thermal stratification in water pool

International Nuclear Information System (INIS)

Verma, P.K.; Chandraker, D.K.; Nayak, A.K.; Vijayan, P.K.

2015-01-01

Large water pools are used as a heat sink for various cooling systems used in industry. In context of advance nuclear reactors like AHWR, it is used as ultimate heat sink for passive systems for decay heat removal and containment cooling. This system incorporates heat exchangers submerged in the large water pool. However, heat transfer by natural convection in pool poses a problem of thermal stratification. Due to thermal stratification hot layers of water accumulate over the relatively cold one. The heat transfer performance of heat exchanger gets deteriorated as a hot fluid envelops it. In the nuclear reactors, the walls of the pool are made of concrete and it may subject to high temperature due to thermal stratification which is not desirable. In this paper, a concept of employing shrouds around the heat source is studied. These shrouds provide a bulk flow in the water pool, thereby facilitating mixing of hot and cold fluid, which eliminate stratification. The concept has been applied to the a scaled model of Gravity Driven Water Pool (GDWP) of AHWR in which Isolation Condensers (IC) tubes are submerged for decay heat removal of AHWR using ICS and thermal stratification phenomenon was predicted with and without shrouds. To demonstrate the adequacy of the effectiveness of shroud arrangement and to validate the simulation methodology of RELAP5/Mod3.2, experiments has been conducted on a scaled model of the pool with and without shroud. (author)

Social Stratification in the Workplace in Nigeria

Directory of Open Access Journals (Sweden)

Emmanuel Obukovwo Okaka

2017-06-01

Full Text Available Nigerian society in pre-colonial era was stratified according to royalty, military might, wealth and religious hierarchy as the case may be. But with the advent of paid employment, the social stratification shifted from a traditional format to one outlined with Western societies. The argument put forward is that social class in modern time has only been re-defined, thereby giving Nigeria a unique social stratification with a strong traditional/religious influence. This paper examined the social stratification in Nigeria with the backdrop of the introduction of paid employment and the impact of this unique social classification in the workplace. In examining social stratification in the workplace, four hundred and eighty respondents were interviewed using structured questionnaire in a onetime survey. Data collected indicates that seventy-nine percent of the surveyed group preferred to be classified with traditional or religious strata than academic class. Indicating that, royalty takes the front seat in the stratification of the Nigerian society even in the work place. This scenario may account for the emphasis Nigerians place on traditional and religious titles over academic titles in almost all sphere of life including the workplace. This calls for the strengthening of the traditional and religious institutions so that they can assist to impart core social values on members of the society, while giving proper honour to those who are accomplished professionals in their various fields of endeavours.

Revealing the timing of ocean stratification using remotely sensed ocean fronts

Science.gov (United States)

Miller, Peter I.; Loveday, Benjamin R.

2017-10-01

Stratification is of critical importance to the circulation, mixing and productivity of the ocean, and is expected to be modified by climate change. Stratification is also understood to affect the surface aggregation of pelagic fish and hence the foraging behaviour and distribution of their predators such as seabirds and cetaceans. Hence it would be prudent to monitor the stratification of the global ocean, though this is currently only possible using in situ sampling, profiling buoys or underwater autonomous vehicles. Earth observation (EO) sensors cannot directly detect stratification, but can observe surface features related to the presence of stratification, for example shelf-sea fronts that separate tidally-mixed water from seasonally stratified water. This paper describes a novel algorithm that accumulates evidence for stratification from a sequence of oceanic front maps, and discusses preliminary results in comparison with in situ data and simulations from 3D hydrodynamic models. In certain regions, this method can reveal the timing of the seasonal onset and breakdown of stratification.

Influence of the variation potential on photosynthetic flows of light energy and electrons in pea.

Science.gov (United States)

Sukhova, Ekaterina; Mudrilov, Maxim; Vodeneev, Vladimir; Sukhov, Vladimir

2018-05-01

Local damage (mainly burning, heating, and mechanical wounding) induces propagation of electrical signals, namely, variation potentials, which are important signals during the life of plants that regulate different physiological processes, including photosynthesis. It is known that the variation potential decreases the rate of CO 2 assimilation by the Calvin-Benson cycle; however, its influence on light reactions has been poorly investigated. The aim of our work was to investigate the influence of the variation potential on the light energy flow that is absorbed, trapped and dissipated per active reaction centre in photosystem II and on the flow of electrons through the chloroplast electron transport chain. We analysed chlorophyll fluorescence in pea leaves using JIP-test and PAM-fluorometry; we also investigated delayed fluorescence. The electrical signals were registered using extracellular electrodes. We showed that the burning-induced variation potential stimulated a nonphotochemical loss of energy in photosystem II under dark conditions. It was also shown that the variation potential gradually increased the flow of light energy absorbed, trapped and dissipated by photosystem II. These changes were likely caused by an increase in the fraction of absorbed light distributed to photosystem II. In addition, the variation potential induced a transient increase in electron flow through the photosynthetic electron transport chain. Some probable mechanisms for the influence of the variation potential on the light reactions of photosynthesis (including the potential role of intracellular pH decrease) are discussed in the work.

Public perceptions and acceptance of induced earthquakes related to energy development

International Nuclear Information System (INIS)

McComas, Katherine A.; Lu, Hang; Keranen, Katie M.; Furtney, Maria A.; Song, Hwansuck

2016-01-01

Growing awareness of the potential for some energy-related activities to induce earthquakes has created a need to understand how the public evaluates the risks of induced earthquakes versus the benefits of energy development. To address this need, this study presents a web survey that used a between-subjects factorial experimental design to explore the views of 325 U.S. adults, who were asked about their experiences with earthquakes; risk perceptions related to different causes of earthquakes (e.g., natural versus induced); and acceptability of earthquakes depending on the benefits, beneficiaries, and decision making process. The results found that participants had more negative feelings toward induced versus naturally occurring earthquakes. Although they judged no earthquake as “acceptable,” participants rated induced earthquakes significantly less acceptable than naturally occurring ones. Attributing the benefits to the provision of renewable energy or climate change mitigation did not increase induced earthquake acceptability, and no particular beneficiary made earthquakes more acceptable, although private companies as beneficiaries made earthquakes less acceptable. Finally, induced earthquake acceptability was significantly higher when people believed that people like them had a voice in the decision to implement the technology that caused the earthquake, underscoring the importance of public engagement in the development of energy technologies. - Highlights: • Human induced earthquakes were perceived as more negative than natural earthquakes. • Attributing benefits to renewable energy did not increase earthquake acceptability. • Acceptability was highest after a procedurally fair decision making process. • Acceptability was lowest following an expert-driven decision.

Transient stratification modelling of a corium pool in a LWR vessel lower head

International Nuclear Information System (INIS)

Le Tellier, R.; Saas, L.; Bajard, S.

2015-01-01

Highlights: • A kinetic stratification model is proposed for the simulation of the in-vessel corium behaviour during a LWR severe accident. • The different associated “modes” of vessel failure by thermal focusing effect are highlighted and discussed. • A sensitivity study for a 1650 MWe GenIII PWR is presented with this model in order to illustrate the associated R&D issues. - Abstract: In the context of light water reactor severe accidents analysis, this paper is focused on one key parameter of in-vessel corium phenomenology: the immiscible phases stratification and its impact on the heat flux distribution at the corium pool lateral boundary with the so-called focusing effect related to a “thin” top metal phase and the potential vessel failure at that point. More particularly, based on the limited knowledge of the stratification transient phenomenon derived from the MASCA-RCW experiment, a basic model is proposed that can be used for corium in lower head sensitivity analyses. It has been implemented in the PROCOR platform developed at CEA Cadarache. A short parametric study on a simple hypothetical transient is presented in order to highlight the different focusing effect “modes” that can be encountered based on this in-vessel corium pool model. An early mode may occur during the formation of the top metal layer while two other modes may appear later during the thinning of this top metal layer because of thermochemically induced mass transfers. Some associated relevant parameters (model or scenario-dependent) and modelling issues are mentioned and illustrated with some results of a Monte-Carlo based sensitivity calculation on the transient behaviour of the corium in the lower head of a 1650 MWe GenIII PWR. Within the limiting modelling hypotheses, the thermal modelling of the steel layer for small (centimetre) heights and the mass diffusivity (limited in this case to the uranium diffusivity in the oxidic layer) are main sensitive parameters

An efficient modeling method for thermal stratification simulation in a BWR suppression pool

Energy Technology Data Exchange (ETDEWEB)

Haihua Zhao; Ling Zou; Hongbin Zhang; Hua Li; Walter Villanueva; Pavel Kudinov

2012-09-01

The suppression pool in a BWR plant not only is the major heat sink within the containment system, but also provides major emergency cooling water for the reactor core. In several accident scenarios, such as LOCA and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; and the pool temperature distribution also affects the NPSHa (Available Net Positive Suction Head) and therefore the performance of the pump which draws cooling water back to the core. Current safety analysis codes use 0-D lumped parameter methods to calculate the energy and mass balance in the pool and therefore have large uncertainty in prediction of scenarios in which stratification and mixing are important. While 3-D CFD methods can be used to analyze realistic 3D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, therefore long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by 1-D transient partial differential equations and substructures such as free or wall jets are modeled with 1-D integral models. This allows very large reductions in computational effort compared to 3-D CFD modeling. The POOLEX experiments at Finland, which was designed to study phenomena relevant to Nordic design BWR suppression pool including thermal stratification and mixing, are used for validation. GOTHIC lumped parameter models are used to obtain boundary conditions for BMIX++ code and CFD simulations. Comparison between the BMIX++, GOTHIC, and CFD calculations against the POOLEX experimental data is discussed in detail.

Quantifying induced effects of subsurface renewable energy storage

Science.gov (United States)

Bauer, Sebastian; Beyer, Christof; Pfeiffer, Tilmann; Boockmeyer, Anke; Popp, Steffi; Delfs, Jens-Olaf; Wang, Bo; Li, Dedong; Dethlefsen, Frank; Dahmke, Andreas

2015-04-01

New methods and technologies for energy storage are required for the transition to renewable energy sources. Subsurface energy storage systems such as salt caverns or porous formations offer the possibility of hosting large amounts of energy or substance. When employing these systems, an adequate system and process understanding is required in order to assess the feasibility of the individual storage option at the respective site and to predict the complex and interacting effects induced. This understanding is the basis for assessing the potential as well as the risks connected with a sustainable usage of these storage options, especially when considering possible mutual influences. For achieving this aim, in this work synthetic scenarios for the use of the geological underground as an energy storage system are developed and parameterized. The scenarios are designed to represent typical conditions in North Germany. The types of subsurface use investigated here include gas storage and heat storage in porous formations. The scenarios are numerically simulated and interpreted with regard to risk analysis and effect forecasting. For this, the numerical simulators Eclipse and OpenGeoSys are used. The latter is enhanced to include the required coupled hydraulic, thermal, geomechanical and geochemical processes. Using the simulated and interpreted scenarios, the induced effects are quantified individually and monitoring concepts for observing these effects are derived. This presentation will detail the general investigation concept used and analyze the parameter availability for this type of model applications. Then the process implementation and numerical methods required and applied for simulating the induced effects of subsurface storage are detailed and explained. Application examples show the developed methods and quantify induced effects and storage sizes for the typical settings parameterized. This work is part of the ANGUS+ project, funded by the German Ministry

The role stratification on Indian ocean mixing under global warming

Science.gov (United States)

Praveen, V.; Valsala, V.; Ravindran, A. M.

2017-12-01

The impact of changes in Indian ocean stratification on mixing under global warming is examined. Previous studies on global warming and associated weakening of winds reported to increase the stratification of the world ocean leading to a reduction in mixing, increased acidity, reduced oxygen and there by a reduction in productivity. However this processes is not uniform and are also modulated by changes in wind pattern of the future. Our study evaluate the role of stratification and surface fluxes on mixing focusing northern Indian ocean. A dynamical downscaling study using Regional ocean Modelling system (ROMS) forced with stratification and surface fluxes from selected CMIP5 models are presented. Results from an extensive set of historical and Representative Concentration Pathways 8.5 (rcp8.5) scenario simulations are used to quantify the distinctive role of stratification on mixing.

A panel of ancestry informative markers to estimate and correct potential effects of population stratification in Han Chinese.

Science.gov (United States)

Qin, Pengfei; Li, Zhiqiang; Jin, Wenfei; Lu, Dongsheng; Lou, Haiyi; Shen, Jiawei; Jin, Li; Shi, Yongyong; Xu, Shuhua

2014-02-01

Population stratification acts as a confounding factor in genetic association studies and may lead to false-positive or false-negative results. Previous studies have analyzed the genetic substructures in Han Chinese population, the largest ethnic group in the world comprising ∼20% of the global human population. In this study, we examined 5540 Han Chinese individuals with about 1 million single-nucleotide polymorphisms (SNPs) and screened a panel of ancestry informative markers (AIMs) to facilitate the discerning and controlling of population structure in future association studies on Han Chinese. Based on genome-wide data, we first confirmed our previous observation of the north-south differentiation in Han Chinese population. Second, we developed a panel of 150 validated SNP AIMs to determine the northern or southern origin of each Han Chinese individual. We further evaluated the performance of our AIMs panel in association studies in simulation analysis. Our results showed that this AIMs panel had sufficient power to discern and control population stratification in Han Chinese, which could significantly reduce false-positive rates in both genome-wide association studies (GWAS) and candidate gene association studies (CGAS). We suggest this AIMs panel be genotyped and used to control and correct population stratification in the study design or data analysis of future association studies, especially in CGAS which is the most popular approach to validate previous reports on genetic associations of diseases in post-GWAS era.

Risk Stratification in Differentiated Thyroid Cancer: An Ongoing Process

Directory of Open Access Journals (Sweden)

Gal Omry-Orbach

2016-01-01

Full Text Available Thyroid cancer is an increasingly common malignancy, with a rapidly rising prevalence worldwide. The social and economic ramifications of the increase in thyroid cancer are multiple. Though mortality from thyroid cancer is low, and most patients will do well, the risk of recurrence is not insignificant, up to 30%. Therefore, it is important to accurately identify those patients who are more or less likely to be burdened by their disease over years and tailor their treatment plan accordingly. The goal of risk stratification is to do just that. The risk stratification process generally starts postoperatively with histopathologic staging, based on the AJCC/UICC staging system as well as others designed to predict mortality. These do not, however, accurately assess the risk of recurrence/persistence. Patients initially considered to be at high risk may ultimately do very well yet be burdened by frequent unnecessary monitoring. Conversely, patients initially thought to be low risk, may not respond to their initial treatment as expected and, if left unmonitored, may have higher morbidity. The concept of risk-adaptive management has been adopted, with an understanding that risk stratification for differentiated thyroid cancer is dynamic and ongoing. A multitude of variables not included in AJCC/UICC staging are used initially to classify patients as low, intermediate, or high risk for recurrence. Over the course of time, a response-to-therapy variable is incorporated, and patients essentially undergo continuous risk stratification. Additional tools such as biochemical markers, genetic mutations, and molecular markers have been added to this complex risk stratification process such that this is essentially a continuum of risk. In recent years, additional considerations have been discussed with a suggestion of pre-operative risk stratification based on certain clinical and/or biologic characteristics. With the increasing prevalence of thyroid cancer but

Noninvasive risk stratification of lethal ventricular arrhythmias and sudden cardiac death after myocardial infarction

Directory of Open Access Journals (Sweden)

Kenji Yodogawa, MD

2014-08-01

Full Text Available Prediction of lethal ventricular arrhythmias leading to sudden cardiac death is one of the most important and challenging problems after myocardial infarction (MI. Identification of MI patients who are prone to ventricular tachyarrhythmias allows for an indication of implantable cardioverter-defibrillator placement. To date, noninvasive techniques such as microvolt T-wave alternans (MTWA, signal-averaged electrocardiography (SAECG, heart rate variability (HRV, and heart rate turbulence (HRT have been developed for this purpose. MTWA is an indicator of repolarization abnormality and is currently the most promising risk-stratification tool for predicting malignant ventricular arrhythmias. Similarly, late potentials detected by SAECG are indices of depolarization abnormality and are useful in risk stratification. However, the role of SAECG is limited because of its low predictive accuracy. Abnormal HRV and HRT patterns reflect autonomic disturbances, which may increase the risk of lethal ventricular arrhythmias, but the existing evidence is insufficient. Further studies of noninvasive assessment may provide a new insight into risk stratification in post-MI patients.

The impact of social stratification on cultural consumption

Directory of Open Access Journals (Sweden)

Tomić Marta

2016-01-01

Full Text Available This paper examines theoretical perspectives, research approaches and research results about the relationship between social stratification and cultural consumption. Paper presents main representatives of three sociological discourses: those who believe that class divisions still exist and that thay had an influence on the social inequalities, especially in the domain of cultural consumption and tastes; authors and researchers who emphasize the impact of social stratification on the formation of cultural stratification, and the third group which consists of those who are advocates of cultural consumptions theories and individualization and cultural tastes which means that membership of a particular social class are not by any cultural influences.

Optimal energy growth in a stably stratified shear flow

Science.gov (United States)

Jose, Sharath; Roy, Anubhab; Bale, Rahul; Iyer, Krithika; Govindarajan, Rama

2018-02-01

Transient growth of perturbations by a linear non-modal evolution is studied here in a stably stratified bounded Couette flow. The density stratification is linear. Classical inviscid stability theory states that a parallel shear flow is stable to exponentially growing disturbances if the Richardson number (Ri) is greater than 1/4 everywhere in the flow. Experiments and numerical simulations at higher Ri show however that algebraically growing disturbances can lead to transient amplification. The complexity of a stably stratified shear flow stems from its ability to combine this transient amplification with propagating internal gravity waves (IGWs). The optimal perturbations associated with maximum energy amplification are numerically obtained at intermediate Reynolds numbers. It is shown that in this wall-bounded flow, the three-dimensional optimal perturbations are oblique, unlike in unstratified flow. A partitioning of energy into kinetic and potential helps in understanding the exchange of energies and how it modifies the transient growth. We show that the apportionment between potential and kinetic energy depends, in an interesting manner, on the Richardson number, and on time, as the transient growth proceeds from an optimal perturbation. The oft-quoted stabilizing role of stratification is also probed in the non-diffusive limit in the context of disturbance energy amplification.

Laser induced energy transfer

International Nuclear Information System (INIS)

Falcone, R.W.

1979-01-01

Two related methods of rapidly transferring stored energy from one excited chemical species to another are described. The first of these, called a laser induced collision, involves a reaction in which the energy balance is met by photons from an intense laser beam. A collision cross section of ca 10 - 17 cm 2 was induced in an experiment which demonstrated the predicted dependence of the cross section on wavelength and power density of the applied laser. A second type of laser induced energy transfer involves the inelastic scattering of laser radiation from energetically excited atoms, and subsequent absorption of the scattered light by a second species. The technique of producing the light, ''anti-Stokes Raman'' scattering of visible and infrared wavelength laser photons, is shown to be an efficient source of narrow bandwidth, high brightness, tunable radiation at vacuum ultraviolet wavelengths by using it to excite a rare gas transition at 583.7 A. In addition, this light source was used to make the first measurement of the isotopic shift of the helium metastable level at 601 A. Applications in laser controlled chemistry and spectroscopy, and proposals for new types of lasers using these two energy transfer methods are discussed

Impact of chromosome alterations, genetic mutations and clonal hematopoiesis of indeterminate potential (CHIP) on the classification and risk stratification of MDS.

Science.gov (United States)

Ganguly, Bani Bandana; Banerjee, Debasis; Agarwal, Mohan B

2018-03-01

The advent of technological development has undoubtedly advanced biological and molecular inputs for better understanding the heterogeneous hematopoietic pre-malignant disorder of the stem cells known as myelodysplastic syndromes (MDS). Chromosomal rearrangements, including del(3q/5q/7q/11q/12p/20q), loss of 5/7/Y, trisomy 8/19, i(17q), etc. frequently detected in MDS with variable frequencies and combinations, are the integral components of the 5-tier risk-stratification and WHO-2016 classification. Observations on mutations in genes involved in RNA-splicing, DNA methylation, chromatin modification, transcription factor, signal transduction/kinases, RAS pathway, cohesin complex, DNA repair and other pathways have given insights in independent effects and biological interaction of co-occurrence on disease-phenotype and treatment outcome. However, recent concepts of clonal hematopoiesis of indeterminate potential (CHIP) and idiopathic cytopenia of undetermined significance (ICUS) have urged a re-definition of mutational events in non-clonal cytopenia and non-MDS healthy elderly but with a higher risk of overt leukemia. Considering gene mutations, chromosomal alterations, CHIP, ICUS and their significance in classification and risk-scoring certainly presents a comprehensive picture of disease-phenotype towards better understanding of MDS-pathogenesis, its evolution to AML and its response to therapeutic agents. The present review summarizes chromosomal and gene mutations, co-existence of mutational complexity, and WHO-2016 classification and risk-stratifications of MDS to facilitate a better understanding of its pathogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Energy-producing system of the membrane potential generation in γ-irradiated Streptococcus faecalis

International Nuclear Information System (INIS)

Fomenko, B.S.

1976-01-01

γ-irradiated (20-100 krads) Str. faecalis cells exhibited increased glycolytic and ATPase activity whereas the ATP level remained unaffected by radiation. It is concluded that the radiation-induced reduction of the membrane potential in Str. faecalis, that has been earlier described, is not connected with the impairment of the energy-producing system of the potential generation

Awortwi et al.: Mixing and stratification relationship on phytoplankton ...

African Journals Online (AJOL)

Awortwi et al.: Mixing and stratification relationship on phytoplankton of Lake Bosomtwe (Ghana) 43 West African Journal of Applied Ecology, vol. 23(2), 2015: 43–62. The Relationship Between Mixing and Stratification Regime on the Phytoplankton of Lake Bo.

Has climate change disrupted stratification patterns in Lake Victoria ...

African Journals Online (AJOL)

Has climate change disrupted stratification patterns in Lake Victoria, East Africa? ... Climate change may threaten the fisheries of Lake Victoria by increasing density differentials in the water column, thereby strengthening stratification and increasing the ... Keywords: deoxygenation, fisheries, global warming, thermocline

European environmental stratifications and typologies

DEFF Research Database (Denmark)

Hazeu, G.W,; Metzger, M.J.; Mücher, C.A.

2011-01-01

their limitations and challenges. As such, they provide a sound basis for describing the factors affecting the robustness of such datasets. The latter is especially relevant, since there is likely to be further interest in European environmental assessment. In addition, advances in data availability and analysis......A range of new spatial datasets classifying the European environment has been constructed over the last few years. These datasets share the common objective of dividing European environmental gradients into convenient units, within which objects and variables of interest have relatively homogeneous...... scale. This paper provides an overview of five recent European stratifications and typologies, constructed for contrasting objectives, and differing in spatial and thematic detail. These datasets are: the Environmental Stratification (EnS), the European Landscape Classification (LANMAP), the Spatial...

Experiments and MPS analysis of stratification behavior of two immiscible fluids

Energy Technology Data Exchange (ETDEWEB)

Li, Gen, E-mail: ligen@fuji.waseda.jp [Cooperative Major in Nuclear Energy, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Oka, Yoshiaki [Cooperative Major in Nuclear Energy, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Furuya, Masahiro; Kondo, Masahiro [Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwado-kita, Komae, Tokyo 201-8511 (Japan)

2013-12-15

Highlights: • Improving numerical stability of MPS method. • Implicitly calculating viscous term in momentum equation for highly viscous fluids. • Validation of the enhanced MPS method by analyzing dam break problem. • Various stratification behavior analysis by experiments and simulations. • Sensitivity analysis of the effects of the fluid viscosity and density difference. - Abstract: Stratification behavior is of great significance in the late in-vessel stage of core melt severe accident of a nuclear reactor. Conventional numerical methods have difficulties in analyzing stratification process accompanying with free surface without depending on empirical correlations. The Moving Particle Semi-implicit (MPS) method, which calculates free surface and multiphase flow without empirical equations, is applicable for analyzing the stratification behavior of fluids. In the present study, the original MPS method was improved to simulate the stratification behavior of two immiscible fluids. The improved MPS method was validated through simulating classical dam break problem. Then, the stratification processes of two fluid columns and injected fluid were investigated through experiments and simulations, using silicone oil and salt water as the simulant materials. The effects of fluid viscosity and density difference on stratification behavior were also sensitively investigated by simulations. Typical fluid configurations at various parametric and geometrical conditions were observed and well predicted by improved MPS method.

Fuel and combustion stratification study of Partially Premixed Combustion

NARCIS (Netherlands)

Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

2016-01-01

Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a

Relationship between thermal stratification and flow patterns in steam-quenching suppression pool

International Nuclear Information System (INIS)

Song, Daehun; Erkan, Nejdet; Jo, Byeongnam; Okamoto, Koji

2015-01-01

Highlights: • Thermal stratification mechanism by direct contact condensation is investigated. • Thermal stratification condition changes according to the flow pattern. • Thermal stratification depends on the force balance between buoyancy and momentum. • Flow pattern change was observed even in the same regime. • Flow pattern is affected by the sensitive force balance. - Abstract: This study aims to examine the relationship between thermal stratification and flow patterns in a steam-quenching suppression pool using particle image velocimetry. Thermal stratification was experimentally evaluated in a depressurized water pool under different steam mass flux conditions. The time evolution of the temperature profile of the suppression pool was presented with the variation of condensation regimes, and steam condensation processes were visualized using a high-speed camera. The thermal stratification condition was classified into full mixing, gradual thermal stratification, and developed thermal stratification. It was found that the condition was determined by the flow patterns depending on the force balance between buoyancy and momentum. The force balance affected both the condensation regime and the flow pattern, and hence, the flow pattern was changed with the condensation regime. However, the force balance had a sensitive influence on the flow in the pool; therefore, distinct flow patterns were observed even in the same condensation regime.

Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma.

Science.gov (United States)

De Paz, Dante; Kao, Huang-Kai; Huang, Yenlin; Chang, Kai-Ping

2017-08-10

Prognosis of advanced oral squamous cell carcinoma remains a challenge for clinicians despite progress in its diagnosis and treatment over the past decades. In this review, we assessed clinicopathological factors and potential biomarkers along with their prognostic relevance in an attempt to develop optimal treatment strategies for these patients. In addition to several pathologic factors that have been proposed to improve prognostic stratification and treatment planning in the eighth edition of the American Joint Committee staging manual on cancer, we reviewed some other imaging and clinicopathological parameters demonstrated to be closely associated with patient prognosis, along with the biomarkers related to novel target or immune therapy. Evaluation of current literature regarding the prognostic stratification used in contemporary clinicopathological studies and progress in the development of targeted or immune therapy may help these patients benefit from tailored and personalized treatment and obtain better oncological results.

Breakup of last glacial deep stratification in the South Pacific

Science.gov (United States)

Basak, Chandranath; Fröllje, Henning; Lamy, Frank; Gersonde, Rainer; Benz, Verena; Anderson, Robert F.; Molina-Kescher, Mario; Pahnke, Katharina

2018-02-01

Stratification of the deep Southern Ocean during the Last Glacial Maximum is thought to have facilitated carbon storage and subsequent release during the deglaciation as stratification broke down, contributing to atmospheric CO2 rise. Here, we present neodymium isotope evidence from deep to abyssal waters in the South Pacific that confirms stratification of the deepwater column during the Last Glacial Maximum. The results indicate a glacial northward expansion of Ross Sea Bottom Water and a Southern Hemisphere climate trigger for the deglacial breakup of deep stratification. It highlights the important role of abyssal waters in sustaining a deep glacial carbon reservoir and Southern Hemisphere climate change as a prerequisite for the destabilization of the water column and hence the deglacial release of sequestered CO2 through upwelling.

GOTHIC code simulation of thermal stratification in POOLEX facility

International Nuclear Information System (INIS)

Li, H.; Kudinov, P.

2009-07-01

Pressure suppression pool is an important element of BWR containment. It serves as a heat sink and steam condenser to prevent containment pressure buildup during loss of coolant accident or safety relief valve opening during normal operations of a BWR. Insufficient mixing in the pool, in case of low mass flow rate of steam, can cause development of thermal stratification and reduction of pressure suppression pool capacity. For reliable prediction of mixing and stratification phenomena validation of simulation tools has to be performed. Data produced in POOLEX/PPOOLEX facility at Lappeenranta University of Technology about development of thermal stratification in a large scale model of a pressure suppression pool is used for GOTHIC lumped and distributed parameter validation. Sensitivity of GOTHIC solution to different boundary conditions and grid convergence study for 2D simulations of POOLEX STB-20 experiment are performed in the present study. CFD simulation was carried out with FLUENT code in order to get additional insights into physics of stratification phenomena. In order to support development of experimental procedures for new tests in the PPOOLEX facility lumped parameter pre-test GOTHIC simulations were performed. Simulations show that drywell and wetwell pressures can be kept within safety margins during a long transient necessary for development of thermal stratification. (au)

GOTHIC code simulation of thermal stratification in POOLEX facility

Energy Technology Data Exchange (ETDEWEB)

Li, H.; Kudinov, P. (Royal Institute of Technology (KTH) (Sweden))

2009-07-15

Pressure suppression pool is an important element of BWR containment. It serves as a heat sink and steam condenser to prevent containment pressure buildup during loss of coolant accident or safety relief valve opening during normal operations of a BWR. Insufficient mixing in the pool, in case of low mass flow rate of steam, can cause development of thermal stratification and reduction of pressure suppression pool capacity. For reliable prediction of mixing and stratification phenomena validation of simulation tools has to be performed. Data produced in POOLEX/PPOOLEX facility at Lappeenranta University of Technology about development of thermal stratification in a large scale model of a pressure suppression pool is used for GOTHIC lumped and distributed parameter validation. Sensitivity of GOTHIC solution to different boundary conditions and grid convergence study for 2D simulations of POOLEX STB-20 experiment are performed in the present study. CFD simulation was carried out with FLUENT code in order to get additional insights into physics of stratification phenomena. In order to support development of experimental procedures for new tests in the PPOOLEX facility lumped parameter pre-test GOTHIC simulations were performed. Simulations show that drywell and wetwell pressures can be kept within safety margins during a long transient necessary for development of thermal stratification. (au)

Improved single particle potential for transport model simulations of nuclear reactions induced by rare isotope beams

International Nuclear Information System (INIS)

Xu Chang; Li Baoan

2010-01-01

Taking into account more accurately the isospin dependence of nucleon-nucleon interactions in the in-medium many-body force term of the Gogny effective interaction, new expressions for the single-nucleon potential and the symmetry energy are derived. Effects of both the spin (isospin) and the density dependence of nuclear effective interactions on the symmetry potential and the symmetry energy are examined. It is shown that they both play a crucial role in determining the symmetry potential and the symmetry energy at suprasaturation densities. The improved single-nucleon potential will be useful for more accurate simulation of nuclear reactions induced by rare-isotope beams within transport models.

Ion induced high energy electron emission from copper

International Nuclear Information System (INIS)

Ruano, G.; Ferron, J.

2008-01-01

We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He + , Ne + and Ar + ) and Li + ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

Quantitative stratification of diffuse parenchymal lung diseases.

Directory of Open Access Journals (Sweden)

Sushravya Raghunath

Full Text Available Diffuse parenchymal lung diseases (DPLDs are characterized by widespread pathological changes within the pulmonary tissue that impair the elasticity and gas exchange properties of the lungs. Clinical-radiological diagnosis of these diseases remains challenging and their clinical course is characterized by variable disease progression. These challenges have hindered the introduction of robust objective biomarkers for patient-specific prediction based on specific phenotypes in clinical practice for patients with DPLD. Therefore, strategies facilitating individualized clinical management, staging and identification of specific phenotypes linked to clinical disease outcomes or therapeutic responses are urgently needed. A classification schema consistently reflecting the radiological, clinical (lung function and clinical outcomes and pathological features of a disease represents a critical need in modern pulmonary medicine. Herein, we report a quantitative stratification paradigm to identify subsets of DPLD patients with characteristic radiologic patterns in an unsupervised manner and demonstrate significant correlation of these self-organized disease groups with clinically accepted surrogate endpoints. The proposed consistent and reproducible technique could potentially transform diagnostic staging, clinical management and prognostication of DPLD patients as well as facilitate patient selection for clinical trials beyond the ability of current radiological tools. In addition, the sequential quantitative stratification of the type and extent of parenchymal process may allow standardized and objective monitoring of disease, early assessment of treatment response and mortality prediction for DPLD patients.

Quantitative Stratification of Diffuse Parenchymal Lung Diseases

Science.gov (United States)

Raghunath, Sushravya; Rajagopalan, Srinivasan; Karwoski, Ronald A.; Maldonado, Fabien; Peikert, Tobias; Moua, Teng; Ryu, Jay H.; Bartholmai, Brian J.; Robb, Richard A.

2014-01-01

Diffuse parenchymal lung diseases (DPLDs) are characterized by widespread pathological changes within the pulmonary tissue that impair the elasticity and gas exchange properties of the lungs. Clinical-radiological diagnosis of these diseases remains challenging and their clinical course is characterized by variable disease progression. These challenges have hindered the introduction of robust objective biomarkers for patient-specific prediction based on specific phenotypes in clinical practice for patients with DPLD. Therefore, strategies facilitating individualized clinical management, staging and identification of specific phenotypes linked to clinical disease outcomes or therapeutic responses are urgently needed. A classification schema consistently reflecting the radiological, clinical (lung function and clinical outcomes) and pathological features of a disease represents a critical need in modern pulmonary medicine. Herein, we report a quantitative stratification paradigm to identify subsets of DPLD patients with characteristic radiologic patterns in an unsupervised manner and demonstrate significant correlation of these self-organized disease groups with clinically accepted surrogate endpoints. The proposed consistent and reproducible technique could potentially transform diagnostic staging, clinical management and prognostication of DPLD patients as well as facilitate patient selection for clinical trials beyond the ability of current radiological tools. In addition, the sequential quantitative stratification of the type and extent of parenchymal process may allow standardized and objective monitoring of disease, early assessment of treatment response and mortality prediction for DPLD patients. PMID:24676019

Wind energy potential in Bulgaria

International Nuclear Information System (INIS)

Shtrakov, Stanko Vl.

2009-01-01

In this study, wind characteristic and wind energy potential in Bulgaria were analyzed using the wind speed data. The wind energy potential at different sites in Bulgaria has been investigated by compiling data from different sources and analyzing it using a software tool. The wind speed distribution curves were obtained by using the Weibull and Rayleigh probability density functions. The results relating to wind energy potential are given in terms of the monthly average wind speed, wind speed probability density function (PDF), wind speed cumulative density function (CDF), and wind speed duration curve. A technical and economic assessment has been made of electricity generation from three wind turbines having capacity of (60, 200, and 500 kW). The yearly energy output capacity factor and the electrical energy cost of kWh produced by the three different turbines were calculated

Utilizing the energy from induced wind produce by highway vehicle motion

International Nuclear Information System (INIS)

Abas Abd Wahab; Tong, C.W.

2000-01-01

A research work has been conducted at the Faculty of mechanical Engineering, Universiti Teknologi Malaysia to utilize energy from airflow induced by moving vehicles along the highway for advertising and signboard lighting. Series of data collections have been made at Km 20 Johor Bahru - Kuala Lumpur Plus Highway. Wind anemometer equipped with data recorder has been placed at the highway divider to measure the wind speed induced by the vehicles moving from Johor Bahru to Kuala Lumpur and vice versa. From the data analysis it has been found that the to and from Kuala Lumpur motion of the vehicles induced a stable and continuous source of airflow (wind) ranges from 2 to 4 m/s. The energy in this induced wind has been estimated and has the potential to be used for the above said purpose. Five design models have been tested in the Faculty of mechanical Engineering Low Speed Wind Tunnel and the twisted vertical blades with circular end covers has proven to be the most efficient and suitable. The optimum sizing of the vertical axis wind turbine has also been determined. The details of the collection of wind induced data and analysis, estimation of energy content, the vertical axis wind turbine models testing and results are presented in this paper. (Author)

Simulation of Thermal Stratification in BWR Suppression Pools with One Dimensional Modeling Method

Energy Technology Data Exchange (ETDEWEB)

Haihua Zhao; Ling Zou; Hongbin Zhang

2014-01-01

The suppression pool in a boiling water reactor (BWR) plant not only is the major heat sink within the containment system, but also provides the major emergency cooling water for the reactor core. In several accident scenarios, such as a loss-of-coolant accident and extended station blackout, thermal stratification tends to form in the pool after the initial rapid venting stage. Accurately predicting the pool stratification phenomenon is important because it affects the peak containment pressure; the pool temperature distribution also affects the NPSHa (available net positive suction head) and therefore the performance of the Emergency Core Cooling System and Reactor Core Isolation Cooling System pumps that draw cooling water back to the core. Current safety analysis codes use zero dimensional (0-D) lumped parameter models to calculate the energy and mass balance in the pool; therefore, they have large uncertainties in the prediction of scenarios in which stratification and mixing are important. While three-dimensional (3-D) computational fluid dynamics (CFD) methods can be used to analyze realistic 3-D configurations, these methods normally require very fine grid resolution to resolve thin substructures such as jets and wall boundaries, resulting in a long simulation time. For mixing in stably stratified large enclosures, the BMIX++ code (Berkeley mechanistic MIXing code in C++) has been developed to implement a highly efficient analysis method for stratification where the ambient fluid volume is represented by one-dimensional (1-D) transient partial differential equations and substructures (such as free or wall jets) are modeled with 1-D integral models. This allows very large reductions in computational effort compared to multi-dimensional CFD modeling. One heat-up experiment performed at the Finland POOLEX facility, which was designed to study phenomena relevant to Nordic design BWR suppression pool including thermal stratification and mixing, is used for

The potential of biogas energy

International Nuclear Information System (INIS)

Acaroglu, M.; Hepbasli, A.; Kocar, G.

2005-01-01

Biogas technology has been known about for a long time, but in recent years the interest in it has significantly increased, especially due to the higher costs and the rapid depletion of fossil fuels as well as their environmental considerations. The main objective of the present study is to investigate the potential of biogas energy in the 15 European Union (EU) countries and in Turkey, which is seeking admission to the EU and is trying to meet EU environmental standards. Biogas energy potential of the 15 EU countries is estimated to be about 800 PJ. Besides this, Turkey's annual animal waste potential is obtained to be about 11.81 million tons with a biogas energy equivalent of 53.6 PJ. It is expected that this study will be helpful in developing highly applicable and productive planning for energy policies towards the optimum utilization of biogas energy. (author)

Effect of layout on surge line thermal stratification

International Nuclear Information System (INIS)

Lai Jianyong; Huang Wei

2011-01-01

In order to analyze and evaluate the effect of layout on the thermal stratification for PWR Pressurizer surge line, numerical simulation by Computational Fluid Dynamics (CFD) method is taken on 6 kinds of layout improvement with 2 improvement schemes, i.e., increasing the obliquity of quasi horizontal section and adding a vertical pipe between the quasi horizontal section and next elbow, and the maximum temperature differences of quasi horizontal section of surge line of various layouts under different flowrate are obtained. The comparison shows that, the increasing of the obliquity of quasi horizontal section can mitigate the thermal stratification phenomena but can not eliminate this phenomena, while the adding of a vertical pipe between the quasi horizontal section and next elbow can effectively mitigate and eliminate the thermal stratification phenomena. (authors)

Horizontal Stratification in Access to Danish University Programmes

DEFF Research Database (Denmark)

Munk, Martin D.; Thomsen, Jens Peter

2018-01-01

a relatively detailed classification of parents’ occupations to determine how students are endowed with different forms of capital, even when their parents would typically be characterised as belonging to the same social group. Second, we distinguish among disciplines and among university institutions...... to explain the dynamics of horizontal stratification in the Danish university system. Using unique and exhaustive register data, including all higher education institutions and the entire 1984 cohort as of the age of 24, we uncover distinct differences in the magnitude and type of horizontal stratification...... in different fields of study and university institutions. Most importantly, we find distinct patterns of horizontal stratification by field of study and parental occupation that would have remained hidden had we used more aggregated classifications for field of study and social origin....

Effect of a two-dimensional potential on the rate of thermally induced escape over the potential barrier

International Nuclear Information System (INIS)

Han, S.; Lapointe, J.; Lukens, J.E.

1992-01-01

The thermally induced escape rate of a particle trapped in a two-dimensional (2D) potential well has been investigated through experiment and numerical simulations. The measurements were performed on a special type of superconducting quantum interference device (SQUID) which has 2 degrees of freedom. The energies associated with the motion perpendicular to (transverse) and along (longitudinal) the escape direction are quite different: the ratio between the transverse and longitudinal small oscillation frequencies is ω t /ω l ∼7. The SQUID's parameters, which were used to determine the potential shape and energy scales were all independently determined. All data were obtained under conditions for which the 2D thermal activation (TA) model is expected to be valid. The results were found in good agreement with the theoretical prediction. The measured thermal activation energy is found to be the same as the barrier height calculated from the independently determined potential parameters. No evidence of apparent potential barrier enhancement recently reported in a similar system was found. In addition, the results of our numerical simulations suggest that the region in which the 2D thermal activation model is applicable may be extended to barriers as low as ΔU∼k BT

Characteristic and Preferences of Green Consumer Stratification As Bases to Formulating Marketing Strategies of Ecolabel-Certified Furniture

Directory of Open Access Journals (Sweden)

Ririn Wulandari

2012-06-01

question. The components used were: satisfaction, safety, socialization, and sustainability, as well as government policies which could open markets. The respondents were 408 potential consumers in Jakarta and its surroundings. The method used was purposive and convenience sampling, in which the survey was conducted at exhibitions and showrooms. Ward Method, Stepwise Discriminant Analysis and Biplot Analysis were used to generate consumer stratifications. Before that, reliability tests were conducted using Crombach Alpha method. In addition, data was explored and reduced using Component Principle Analysis. Preference analysis was performed using the method proposed by Thurston Case V. This study results four stratifications of green consumers. There were similarities and differences in preference on each of the stratification of the component of green marketing strategy as well as the marketing strategies of furniture-certified ecolabel for the targeted consumers.

Ion induced high energy electron emission from copper

Energy Technology Data Exchange (ETDEWEB)

Ruano, G. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)], E-mail: gdruano@ceride.gov.ar; Ferron, J. [Instituto de Desarrollo Tecnologico para la Industria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina); Departamento de Ingenieria de Materiales, Facultad de Ingenieria Quimica, Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional del Litoral Gueemes 3450 CC 91, 3000 Santa Fe (Argentina)

2008-11-15

We present measurements of secondary electron emission from Cu induced by low energy bombardment (1-5 keV) of noble gas (He{sup +}, Ne{sup +} and Ar{sup +}) and Li{sup +} ions. We identify different potential and kinetic mechanisms and find the presence of high energetic secondary electrons for a couple of ion-target combinations. In order to understand the presence of these fast electrons we need to consider the Fermi shuttle mechanism and the different ion neutralization efficiencies.

Stabilization of mitochondrial membrane potential prevents doxorubicin-induced cardiotoxicity in isolated rat heart

International Nuclear Information System (INIS)

Montaigne, David; Marechal, Xavier; Baccouch, Riadh; Modine, Thomas; Preau, Sebastien; Zannis, Konstantinos; Marchetti, Philippe; Lancel, Steve; Neviere, Remi

2010-01-01

The present study was undertaken to examine the effects of doxorubicin on left ventricular function and cellular energy state in intact isolated hearts, and, to test whether inhibition of mitochondrial membrane potential dissipation would prevent doxorubicin-induced mitochondrial and myocardial dysfunction. Myocardial contractile performance and mitochondrial respiration were evaluated by left ventricular tension and its first derivatives and cardiac fiber respirometry, respectively. NADH levels, mitochondrial membrane potential and glucose uptake were monitored non-invasively via epicardial imaging of the left ventricular wall of Langendorff-perfused rat hearts. Heart performance was reduced in a time-dependent manner in isolated rat hearts perfused with Krebs-Henseleit solution containing 1 μM doxorubicin. Compared with controls, doxorubicin induced acute myocardial dysfunction (dF/dt max of 105 ± 8 mN/s in control hearts vs. 49 ± 7 mN/s in doxorubicin-treated hearts; *p < 0.05). In cardiac fibers prepared from perfused hearts, doxorubicin induced depression of mitochondrial respiration (respiratory control ratio of 4.0 ± 0.2 in control hearts vs. 2.2 ± 0.2 in doxorubicin-treated hearts; *p < 0.05) and cytochrome c oxidase kinetic activity (24 ± 1 μM cytochrome c/min/mg in control hearts vs. 14 ± 3 μM cytochrome c/min/mg in doxorubicin-treated hearts; *p < 0.05). Acute cardiotoxicity induced by doxorubicin was accompanied by NADH redox state, mitochondrial membrane potential, and glucose uptake reduction. Inhibition of mitochondrial permeability transition pore opening by cyclosporine A largely prevented mitochondrial membrane potential dissipation, cardiac energy state and dysfunction. These results suggest that in intact hearts an impairment of mitochondrial metabolism is involved in the development of doxorubicin cardiotoxicity.

Stratification for smoking in case-cohort studies of genetic polymorphisms and lung cancer

DEFF Research Database (Denmark)

Sørensen, Mette; López, Ana García; Andersen, Per Kragh

2009-01-01

and adjustment for smoking on the estimated effect of polymorphisms on lung cancer risk was explored in the case-cohort design. We used an empirical and a statistical simulation approach. The stratification strategies were: no smoking stratification, stratification for smoking status and stratification......The risk estimates obtained in studies of genetic polymorphisms and lung cancer differ markedly between studies, which might be due to chance or differences in study design, in particular the stratification/match of comparison group. The effect of different strategies for stratification...... for smoking duration. The study base was a prospective follow-up study with 57,053 participants. In the simulation approach the glutathione S-transferase T1 null polymorphism, as a model of any polymorphism, was added to simulated data in two different ways, assuming either absence or presence of association...

Predictions of stratification in cold leg components using virtual noding schemes

International Nuclear Information System (INIS)

Piper, R.B.; Hassan, Y.A.; Banerjee, S.S.; Barsamian, H.R.; Cebull, P.P.

1996-01-01

In this investigation, a virtual noding scheme is used with RELAP5/MOD3.2 to capture thermal stratification effects in a small-break loss-of-coolant accident (LOCA) simulation. A three-dimensional code (CFD-ACE) has also been used to observe the stratification effects in a similar situation. Stratification temperature differences of the simulations compare well with that of the experiment. The Froude number was also evaluated

Role and potential of renewable energy and energy efficiency for global energy supply

Energy Technology Data Exchange (ETDEWEB)

Krewitt, Wolfram; Nienhaus, Kristina [German Aerospace Center e.V. (DLR), Stuttgart (Germany); Klessmann, Corinna; Capone, Carolin; Stricker, Eva [Ecofys Germany GmbH, Berlin (Germany); Graus, Wina; Hoogwijk, Monique [Ecofys Netherlands BV, Utrecht (Netherlands); Supersberger, Nikolaus; Winterfeld, Uta von; Samadi, Sascha [Wuppertal Institute for Climate, Environment and Energy GmbH, Wuppertal (Germany)

2009-12-15

The analysis of different global energy scenarios in part I of the report confirms that the exploitation of energy efficiency potentials and the use of renewable energies play a key role in reaching global CO2 reduction targets. An assessment on the basis of a broad literature research in part II shows that the technical potentials of renewable energy technologies are a multiple of today's global final energy consumption. The analysis of cost estimates for renewable electricity generation technologies and even long term cost projections across the key studies in part III demonstrates that assumptions are in reasonable agreement. In part IV it is shown that by implementing technical potentials for energy efficiency improvements in demand and supply sectors by 2050 can be limited to 48% of primary energy supply in IEA's ''Energy Technology Perspectives'' baseline scenario. It was found that a large potential for cost-effective measures exists, equivalent to around 55-60% of energy savings of all included efficiency measures (part V). The results of the analysis on behavioural changes in part VI show that behavioural dimensions are not sufficiently included in energy scenarios. Accordingly major research challenges are revealed. (orig.)

Combustion Stratification for Naphtha from CI Combustion to PPC

KAUST Repository

Vallinayagam, R.

2017-03-28

This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed. At early SOI, combustion phasing depends on both intake air temperature and SOI. In order to match the combustion phasing (CA50) of diesel, the intake air temperature is increased to 90°C for naphtha. The combustion stratification from CI to PPC is also investigated for various level of dilution by displacing oxygen with nitrogen in the intake. The start of combustion (SOC) was delayed with the increase in dilution and to compensate for this, the intake air temperature is increased. The mixture homogeneity is enhanced for higher dilution due to longer ignition delay. The results show that high speed image is initially blue and then turned yellow, indicating soot formation and oxidation. The luminosity of combustion images decreases with early SOI and increased dilution. The images are processed to generate the level of stratification based on the image intensity. The level of stratification is same for diesel and naphtha at various SOI. When O concentration in the intake is decreased to 17.7% and 14

Potential energy savings and thermal comfort

DEFF Research Database (Denmark)

Jensen, Karsten Ingerslev; Rudbeck, Claus Christian; Schultz, Jørgen Munthe

1996-01-01

The simulation results on the energy saving potential and influence on indoor thermal comfort by replacement of common windows with aerogel windows as well as commercial low-energy windows are described and analysed.......The simulation results on the energy saving potential and influence on indoor thermal comfort by replacement of common windows with aerogel windows as well as commercial low-energy windows are described and analysed....

Drainage and Stratification Kinetics of Foam Films

Science.gov (United States)

Zhang, Yiran; Sharma, Vivek

2014-03-01

Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Foam lifetime, drainage kinetics and stability are strongly influenced by surfactant type (ionic vs non-ionic), and added proteins, particles or polymers modify typical responses. The rate at which fluid drains out from a foam film, i.e. drainage kinetics, is determined in the last stages primarily by molecular interactions and capillarity. Interestingly, for certain low molecular weight surfactants, colloids and polyelectrolyte-surfactant mixtures, a layered ordering of molecules, micelles or particles inside the foam films leads to a stepwise thinning phenomena called stratification. Though stratification is observed in many confined systems including foam films containing particles or polyelectrolytes, films containing globular proteins seem not to show this behavior. Using a Scheludko-type cell, we experimentally study the drainage and stratification kinetics of horizontal foam films formed by protein-surfactant mixtures, and carefully determine how the presence of proteins influences the hydrodynamics and thermodynamics of foam films.

Centrifugal potential energy : an astounding renewable energy concept

Energy Technology Data Exchange (ETDEWEB)

Oduniyi, I.A. [Aled Conglomerate Nigeria Ltd., Lagos (Nigeria)

2010-07-01

A new energy concept known as centrifugal potential energy was discussed. This new energy concept is capable of increasing the pressure, temperature and enthalpy of a fluid, without having to apply work or heat transfer to the fluid. It occurs through a change in the centrifugal potential energy of the flowing fluid in a rotating frame of reference or a centrifugal force field, where work is performed internally by the centrifugal weight of the fluid. This energy concept has resulted in new energy equations, such as the Rotational Frame Bernoulli's Equation for liquids and the Rotational Frame Steady-Flow Energy Equation for gases. Applications of these equations have been incorporated into the design of centrifugal field pumps and compressors. Rather than compressing a fluid with a physical load transfer, these devices can compress a fluid via the effect of centrifugal force applied to the object. A large amount of energy is therefore produced when this high pressure compressed working fluid expands in a turbine. When water is used as the working fluid, it could reach renewable energy densities in the range of 25-100 kJ/kg of water. When atmospheric air is used, it could reach energy densities in the range of 500-1,500 kJ/kg of air.

Renewable energy costs, potentials, barriers: Conceptual issues

International Nuclear Information System (INIS)

Verbruggen, Aviel; Fischedick, Manfred; Moomaw, William; Weir, Tony; Nadai, Alain; Nilsson, Lars J.; Nyboer, John; Sathaye, Jayant

2010-01-01

Renewable energy can become the major energy supply option in low-carbon energy economies. Disruptive transformations in all energy systems are necessary for tapping widely available renewable energy resources. Organizing the energy transition from non-sustainable to renewable energy is often described as the major challenge of the first half of the 21st century. Technological innovation, the economy (costs and prices) and policies have to be aligned to achieve full renewable energy potentials, and barriers impeding that growth need to be removed. These issues are also covered by IPCC's special report on renewable energy and climate change to be completed in 2010. This article focuses on the interrelations among the drivers. It clarifies definitions of costs and prices, and of barriers. After reviewing how the third and fourth assessment reports of IPCC cover mitigation potentials and commenting on definitions of renewable energy potentials in the literature, we propose a consistent set of potentials of renewable energy supplies.

Eddy-driven stratification initiates North Atlantic spring phytoplankton blooms.

Science.gov (United States)

Mahadevan, Amala; D'Asaro, Eric; Lee, Craig; Perry, Mary Jane

2012-07-06

Springtime phytoplankton blooms photosynthetically fix carbon and export it from the surface ocean at globally important rates. These blooms are triggered by increased light exposure of the phytoplankton due to both seasonal light increase and the development of a near-surface vertical density gradient (stratification) that inhibits vertical mixing of the phytoplankton. Classically and in current climate models, that stratification is ascribed to a springtime warming of the sea surface. Here, using observations from the subpolar North Atlantic and a three-dimensional biophysical model, we show that the initial stratification and resulting bloom are instead caused by eddy-driven slumping of the basin-scale north-south density gradient, resulting in a patchy bloom beginning 20 to 30 days earlier than would occur by warming.

Short-term versus long-term heart rate variability in ischemic cardiomyopathy risk stratification

Directory of Open Access Journals (Sweden)

Andreas eVoss

2013-12-01

Full Text Available In industrialized countries with aging populations, heart failure affects 0.3%-2% of the general population. The investigation of 24h-ECG recordings revealed the potential of nonlinear indices of heart rate variability (HRV for enhanced risk stratification in patients with ischemic heart failure (IHF. However, long-term analyses are time-consuming, expensive and delay the initial diagnosis. The objective of this study was to investigate whether 30min short-term HRV analysis is sufficient for comparable risk stratification in IHF in comparison to 24h-HRV analysis. From 256 IHF patients (221 at low risk (IHFLR and 35 at high risk (IHFHR a 24h beat-to-beat time series b the first 30min segment c the 30min most stationary day segment and d the 30min most stationary night segment were investigated. We calculated linear (time and frequency domain and nonlinear HRV analysis indices. Optimal parameter sets for risk stratification in IHF were determined for 24 hours and for each 30min segment by applying discriminant analysis on significant clinical and non-clinical indices. Long- and short-term HRV indices from frequency domain and particularly from nonlinear dynamics revealed high univariate significances (p

Near-Surface Effects of Free Atmosphere Stratification in Free Convection

NARCIS (Netherlands)

Mellado, Juan Pedro; Heerwaarden, van C.C.; Garcia, Jade Rachele

2016-01-01

The effect of a linear stratification in the free atmosphere on near-surface properties in a free convective boundary layer (CBL) is investigated by means of direct numerical simulation. We consider two regimes: a neutral stratification regime, which represents a CBL that grows into a residual

Energy potential of agricultural crops in Kosovo

International Nuclear Information System (INIS)

Sahiti, Naser; Sfishta, Avni; Gramatikov, Plamen

2015-01-01

Primary energy mix in Kosovo with 98 % consisting of lignite and only 2 % of water is far from portfolio of primary energy sources which could contribute to a sustainable and environmental friendly energy supply of the country. In order to improve the situation, government is supporting activities in favor of upgrading of electricity production capacities based on Renewable Energy Sources. Corresponding action plans and feed in tariffs are already in place. However, prior to any investment, one needs specific results on available potential. Current study provides results of the analysis of Kosovo potential for energy production by using of agricultural crops. Study is based on national statistics on available agricultural crops in Kosovo and provides results on biomass potential of crops, corresponding energy potential and an assessment of financial cost of energy produced.

Energy potential of region and its quantitative assessment

Directory of Open Access Journals (Sweden)

Tatyana Aleksandrovna Kovalenko

2013-09-01

Full Text Available The purpose of the article is the development of the concept of the energy potential of the region (EPR, the analysis of the existing structure of relationships for the EPR elements in Ukraine and improvement of a quantitative assessment of energy potential of the region (country. The methods of an assessment of the existing condition of energy potential of the territory are the subject matter of the research. As a result of the analysis of concept’s definitions of energy potential of the region, it has further development and included the consumer potential of energy resources and capacity of management. The structure of relationships between elements of energy potential is developed for the Ukraine region. The new economic indicator — the realized energy potential is offered for an EPR assessment. By means of this indicator, the assessment of energy potential for the different countries of the world and a number of Ukraine areas of is performed.

Revealing the timing of ocean stratification using remotely-sensed ocean fronts: links with marine predators

Science.gov (United States)

Miller, P. I.; Loveday, B. R.

2016-02-01

Stratification is of critical importance to the mixing and productivity of the ocean, though currently it can only be measured using in situ sampling, profiling buoys or underwater autonomous vehicles. Stratification is understood to affect the surface aggregation of pelagic fish and hence the foraging behaviour and distribution of their predators such as seabirds and cetaceans. Satellite Earth observation sensors cannot directly detect stratification, but can observe surface features related to the presence of stratification, for example shelf-sea fronts that separate tidally-mixed water from seasonally stratified water. This presentation describes a novel algorithm that accumulates evidence for stratification from a sequence of oceanic front maps, and in certain regions can reveal the timing of the seasonal onset and breakdown of stratification. Initial comparisons will be made with seabird locations acquired through GPS tagging. If successful, a remotely-sensed stratification timing index would augment the ocean front metrics already developed at PML, that have been applied in over 20 journal articles relating marine predators to ocean fronts. The figure below shows a preliminary remotely-sensed 'stratification' index, for 25-31 Jul. 2010, where red indicates water with stronger evidence for stratification.

PPOOLEX experiments on thermal stratification and mixing

Energy Technology Data Exchange (ETDEWEB)

Puustinen, M.; Laine, J.; Raesaenen, A. (Lappeenranta Univ. of Technology, Nuclear Safety Research Unit (Finland))

2009-08-15

The results of the thermal stratification experiments in 2008 with the PPOOLEX test facility are presented. PPOOLEX is a closed vessel divided into two compartments, dry well and wet well. Extra temperature measurements for capturing different aspects of the investigated phenomena were added before the experiments. The main purpose of the experiment series was to generate verification data for evaluating the capability of GOTHIC code to predict stratification and mixing phenomena. Altogether six experiments were carried out. Heat-up periods of several thousand seconds by steam injection into the dry well compartment and from there into the wet well water pool were recorded. The initial water bulk temperature was 20 deg. C. Cooling periods of several days were included in three experiments. A large difference between the pool bottom and top layer temperature was measured when small steam flow rates were used. With higher flow rates the mixing effect of steam discharge delayed the start of stratification until the pool bulk temperature exceeded 50 deg. C. The stratification process was also different in these two cases. With a small flow rate stratification was observed only above and just below the blowdown pipe outlet elevation. With a higher flow rate over a 30 deg. C temperature difference between the pool bottom and pipe outlet elevation was measured. Elevations above the pipe outlet indicated almost linear rise until the end of steam discharge. During the cooling periods the measurements of the bottom third of the pool first had an increasing trend although there was no heat input from outside. This was due to thermal diffusion downwards from the higher elevations. Heat-up in the gas space of the wet well was quite strong, first due to compression by pressure build-up and then by heat conduction from the hot dry well compartment via the intermediate floor and test vessel walls and by convection from the upper layers of the hot pool water. The gas space

PPOOLEX experiments on thermal stratification and mixing

International Nuclear Information System (INIS)

Puustinen, M.; Laine, J.; Raesaenen, A.

2009-08-01

The results of the thermal stratification experiments in 2008 with the PPOOLEX test facility are presented. PPOOLEX is a closed vessel divided into two compartments, dry well and wet well. Extra temperature measurements for capturing different aspects of the investigated phenomena were added before the experiments. The main purpose of the experiment series was to generate verification data for evaluating the capability of GOTHIC code to predict stratification and mixing phenomena. Altogether six experiments were carried out. Heat-up periods of several thousand seconds by steam injection into the dry well compartment and from there into the wet well water pool were recorded. The initial water bulk temperature was 20 deg. C. Cooling periods of several days were included in three experiments. A large difference between the pool bottom and top layer temperature was measured when small steam flow rates were used. With higher flow rates the mixing effect of steam discharge delayed the start of stratification until the pool bulk temperature exceeded 50 deg. C. The stratification process was also different in these two cases. With a small flow rate stratification was observed only above and just below the blowdown pipe outlet elevation. With a higher flow rate over a 30 deg. C temperature difference between the pool bottom and pipe outlet elevation was measured. Elevations above the pipe outlet indicated almost linear rise until the end of steam discharge. During the cooling periods the measurements of the bottom third of the pool first had an increasing trend although there was no heat input from outside. This was due to thermal diffusion downwards from the higher elevations. Heat-up in the gas space of the wet well was quite strong, first due to compression by pressure build-up and then by heat conduction from the hot dry well compartment via the intermediate floor and test vessel walls and by convection from the upper layers of the hot pool water. The gas space

Temperature stratification in a hot water tank with circulation pipe

DEFF Research Database (Denmark)

Andersen, Elsa

1998-01-01

The aim of the project is to investigate the change in temperature stratification due to the operation of a circulation pipe. Further, putting forward rules for design of pipe inlet in order not to disturb the temperature stratification in the hot water tank. A validated computer model based on t...

Future bio-energy potential under various natural constraints

International Nuclear Information System (INIS)

Vuuren, Detlef P. van; Vliet, Jasper van; Stehfest, Elke

2009-01-01

Potentials for bio-energy have been estimated earlier on the basis of estimates of potentially available land, excluding certain types of land use or land cover (land required for food production and forests). In this paper, we explore how such estimates may be influenced by other factors such as land degradation, water scarcity and biodiversity concerns. Our analysis indicates that of the original bio-energy potential estimate of 150, 80 EJ occurs in areas classified as from mild to severe land degradation, water stress, or with high biodiversity value. Yield estimates were also found to have a significant impact on potential estimates. A further 12.5% increase in global yields would lead to an increase in bio-energy potential of about 50%. Changes in bio-energy potential are shown to have a direct impact on bio-energy use in the energy model TIMER, although the relevant factor is the bio-energy potential at different cost levels and not the overall potential.

Induced gravity with Higgs potential. Elementary interactions and quantum processes

International Nuclear Information System (INIS)

Bezares Roder, Nils Manuel

2010-01-01

This work is intended to first serve as introduction in fundamental subjects of physics in order to be then able to review the mechanism of symmetry breakdown and its essential character in physics. It introduces the concept of scalar-tensor theories of gravity based on Bergmann-Wagoner models with a Higgs potential. The main physical context aimed is the problem of Dark Matter and Dark Energy. On the one hand, there is gravitation. Within this context, we have Dark Matter as an especially relevant concept. This work entails the following main contributions: - General features of Einstein's theory are introduced together with generalities of the different elementary interactions of physics from which the concepts of dark sectors and Higgs Mechanism are derived. - The concept of symmetry breaking and especially the Higgs Mechanism of mass generation are discussed in their relevance for the most different subjects of physics, especially in relation to the Standard Model of elementary particle physics with elementary Higgs fields. - Scalar-Tensor Theories are introduced in order to build in them the process of Higgs Mechanism. This is then fulfilled with a theory of induced gravity with a Higgs potential which seems renormalizable according to deWitt's power counting criterion, and with mass-generating Higgs fields which only couple gravitationally as well as with Higgs fields which act analogously to cosmon fields. - Further, the energy density of the gravitational field is derived for the specific model of induced gravity from an analogy to electrodynamics. It is shown that a nonvanishing value of pressure related to the scalar field is necessary in order to reproduce standard linear solar-relativistic dynamics. Within astrophysical considerations for flat rotation curves of galaxies, a possible dark-matter behavior is concluded within spherical symmetry. The scalar field and the dark-matter profile of total energy density are derived. An analogous relation between

Induced gravity with Higgs potential. Elementary interactions and quantum processes

Energy Technology Data Exchange (ETDEWEB)

Bezares Roder, Nils Manuel

2010-07-01

This work is intended to first serve as introduction in fundamental subjects of physics in order to be then able to review the mechanism of symmetry breakdown and its essential character in physics. It introduces the concept of scalar-tensor theories of gravity based on Bergmann-Wagoner models with a Higgs potential. The main physical context aimed is the problem of Dark Matter and Dark Energy. On the one hand, there is gravitation. Within this context, we have Dark Matter as an especially relevant concept. This work entails the following main contributions: - General features of Einstein's theory are introduced together with generalities of the different elementary interactions of physics from which the concepts of dark sectors and Higgs Mechanism are derived. - The concept of symmetry breaking and especially the Higgs Mechanism of mass generation are discussed in their relevance for the most different subjects of physics, especially in relation to the Standard Model of elementary particle physics with elementary Higgs fields. - Scalar-Tensor Theories are introduced in order to build in them the process of Higgs Mechanism. This is then fulfilled with a theory of induced gravity with a Higgs potential which seems renormalizable according to deWitt's power counting criterion, and with mass-generating Higgs fields which only couple gravitationally as well as with Higgs fields which act analogously to cosmon fields. - Further, the energy density of the gravitational field is derived for the specific model of induced gravity from an analogy to electrodynamics. It is shown that a nonvanishing value of pressure related to the scalar field is necessary in order to reproduce standard linear solar-relativistic dynamics. Within astrophysical considerations for flat rotation curves of galaxies, a possible dark-matter behavior is concluded within spherical symmetry. The scalar field and the dark-matter profile of total energy density are derived. An analogous

Experimental study on the thermal stratification in the branch of NPP

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Nyung; Hwang, Seong Hong [Kyunghee Univ., Seoul (Korea, Republic of)

2004-02-15

As more experience is accumulated in the operation of existing nuclear power plants, the long term effects of thermal-hydraulic phenomena, unaccounted in the original designs, have been observed. One such phenomenon is thermal stratification, which has caused through-wall cracks, thermal fatigue, unexpected piping displacements and pipe support damage. Thermal stratification is a phenomenon as temperature layers are formed in the component or piping due to the density difference between hot and cold water. The thermal stratification phenomena in nuclear power plant observed in the pressurizer surge line, and in the piping of feedwater system, Safety Injection System(SIS), residual heat removal system (or shutdown cooling system), and chemical and volume control system during the design transients. A set of experiment has been performed to predict the temperature distribution in the branch piping of nuclear power plant(Ulchin unit 3 and 4) due to the turbulent penetration, the heat transfer through valve disk and valve leakage. The test facility scaled down to 1/10 has been designed and constructed to simulate the thermal stratification in the piping of safety injection system and shutdown cooling system of Ulchin 3 and 4. The experimental results show that the turbulent penetration depth could be : extended to the end of the vertical pipe, and thermal stratification due to the heat transfer through the valve disk to the end of horizontal pipe behind the valve disk. Finally, thermal stratification could effected by the location of valve leakage.

Molecular reclassification of Crohn's disease: a cautionary note on population stratification.

Science.gov (United States)

Maus, Bärbel; Jung, Camille; Mahachie John, Jestinah M; Hugot, Jean-Pierre; Génin, Emmanuelle; Van Steen, Kristel

2013-01-01

Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn's disease (CD) patients are heterogeneous with regard to disease location and disease extent. The genetic susceptibility to Crohn's disease is widely acknowledged and has been demonstrated by identification of over 100 CD associated genetic loci. However, relating CD subphenotypes to disease susceptible loci has proven to be a difficult task. In this paper we discuss the use of cluster analysis on genetic markers to identify genetic-based subgroups while taking into account possible confounding by population stratification. We show that it is highly relevant to consider the confounding nature of population stratification in order to avoid that detected clusters are strongly related to population groups instead of disease-specific groups. Therefore, we explain the use of principal components to correct for population stratification while clustering affected individuals into genetic-based subgroups. The principal components are obtained using 30 ancestry informative markers (AIM), and the first two PCs are determined to discriminate between continental origins of the affected individuals. Genotypes on 51 CD associated single nucleotide polymorphisms (SNPs) are used to perform latent class analysis, hierarchical and Partitioning Around Medoids (PAM) cluster analysis within a sample of affected individuals with and without the use of principal components to adjust for population stratification. It is seen that without correction for population stratification clusters seem to be influenced by population stratification while with correction clusters are unrelated to continental origin of individuals.

Molecular reclassification of Crohn's disease: a cautionary note on population stratification.

Directory of Open Access Journals (Sweden)

Bärbel Maus

Full Text Available Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn's disease (CD patients are heterogeneous with regard to disease location and disease extent. The genetic susceptibility to Crohn's disease is widely acknowledged and has been demonstrated by identification of over 100 CD associated genetic loci. However, relating CD subphenotypes to disease susceptible loci has proven to be a difficult task. In this paper we discuss the use of cluster analysis on genetic markers to identify genetic-based subgroups while taking into account possible confounding by population stratification. We show that it is highly relevant to consider the confounding nature of population stratification in order to avoid that detected clusters are strongly related to population groups instead of disease-specific groups. Therefore, we explain the use of principal components to correct for population stratification while clustering affected individuals into genetic-based subgroups. The principal components are obtained using 30 ancestry informative markers (AIM, and the first two PCs are determined to discriminate between continental origins of the affected individuals. Genotypes on 51 CD associated single nucleotide polymorphisms (SNPs are used to perform latent class analysis, hierarchical and Partitioning Around Medoids (PAM cluster analysis within a sample of affected individuals with and without the use of principal components to adjust for population stratification. It is seen that without correction for population stratification clusters seem to be influenced by population stratification while with correction clusters are unrelated to continental origin of individuals.

Potential of renewable and alternative energy sources

Science.gov (United States)

Konovalov, V.; Pogharnitskaya, O.; Rostovshchikova, A.; Matveenko, I.

2015-11-01

The article deals with application potential of clean alternative renewable energy sources. By means of system analysis the forecast for consumption of electrical energy in Tomsk Oblast as well as main energy sources of existing energy system have been studied up to 2018. Engineering potential of renewable and alternative energy sources is evaluated. Besides, ranking in the order of their efficiency descending is performed. It is concluded that Tomsk Oblast has high potential of alternative and renewable energy sources, among which the most promising development perspective is implementation of gasification stations to save fuel consumed by diesel power stations as well as building wind-power plants.

Phenolic acids potentiate colistin-mediated killing of Acinetobacter baumannii by inducing redox imbalance.

Science.gov (United States)

Ajiboye, Taofeek O; Skiebe, Evelyn; Wilharm, Gottfried

2018-05-01

Phenolic acids with catechol groups are good prooxidants because of their low redox potential. In this study, we provided data showing that phenolic acids, caffeic acid, gallic acid and protocatechuic acid, enhanced colistin-mediated bacterial death by inducing redox imbalance. The minimum inhibitory concentrations of these phenolic acids against Acinetobacter baumannii AB5075 were considerably lowered for ΔsodB and ΔkatG mutants. Checkerboard assay shows synergistic interactions between colistin and phenolic acids. The phenolic acids exacerbated colistin-induced oxidative stress in A. baumannii AB5075 through increased superoxide anion generation, NAD + /NADH and ADP/ATP ratio. In parallel, the level of reduced glutathione was significantly lowered. We conclude that phenolic acids potentiate colistin-induced oxidative stress in A. baumannii AB5075 by increasing ROS generation, energy metabolism and electron transport chain activity with a concomitant decrease in glutathione. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Fossil energy savings potential of sugar cane bio-energy systems

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Thu Lan T. [Department of Agroecology, Aarhus University, Tjele (Denmark); The Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Hermansen, John E. [Department of Agroecology, Aarhus University, Tjele (Denmark); Sagisaka, Masayuki [Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, Tsukuba (Japan)

2009-11-15

One important rationale for bio-energy systems is their potential to save fossil energy. Converting a conventional sugar mill into a bio-energy process plant would contribute to fossil energy savings via the extraction of renewable electricity and ethanol substituting for fossil electricity and gasoline, respectively. This paper takes a closer look at the Thai sugar industry and examines two practical approaches that will enhance fossil energy savings. The first one addresses an efficient extraction of energy in the form of electricity from the excess bagasse and cane trash. The second while proposing to convert molasses or sugar cane to ethanol stresses the use of bagasse as well as distillery spent wash to replace coal in meeting ethanol plants' energy needs. The savings potential achieved with extracting ethanol from surplus sugar versus current practice in sugar industry in Thailand amounts to 15 million barrels of oil a year. Whether the saving benefits could be fully realized, however, depends on how well the potential land use change resulting from an expansion of ethanol production is managed. The results presented serve as a useful guidance to formulate strategies that enable optimum utilization of biomass as an energy source. (author)

Assessment of wind energy potential in China

Institute of Scientific and Technical Information of China (English)

Zhu Rong; Zhang De; Wang Yuedong; Xing Xuhuang; Li Zechun

2009-01-01

China wind atlas was made by numerical simulation and the wind energy potential in China was calculated. The model system for wind energy resource assessment was set up based on Canadian Wind Energy Simulating Toolkit (WEST) and the simulating method was as follows. First, the weather classes were obtained depend on meteorological data of 30 years. Then, driven by the initial meteorological field produced by each weather class, the meso-scale model ran for the distribution of wind energy resources according each weather class condition one by one. Finally, averaging all the modeling output weighted by the occurrence frequency of each weather class, the annual mean distribution of wind energy resources was worked out. Compared the simulated wind energy potential with other results from several ac-tivities and studies for wind energy resource assessment, it is found that the simulated wind energy potential in mainland of China is 3 times that from the second and the third investigations for wind energy resources by CMA, and is similar to the wind energy potential obtained by NREL in Solar and Wind Energy Resource Assessment (SWERA) project. The simulated offshore wind energy potential of China seems smaller than the true value. According to the simulated results of CMA and considering lots of limited factors to wind energy development, the final conclusion can be obtained that the wind energy availability in China is 700～1 200 GW, in which 600～1 000 GW is in mainland and 100～200 GW is on offshore, and wind power will become the important part of energy composition in future.

Gravitational Zero Point Energy induces Physical Observables

OpenAIRE

Garattini, Remo

2010-01-01

We consider the contribution of Zero Point Energy on the induced Cosmological Constant and on the induced Electric/Magnetic charge in absence of matter fields. The method is applicable to every spherically symmetric background. Extensions to a generic $f(R) $ theory are also allowed. Only the graviton appears to be fundamental to the determination of Zero Point Energy.

Energy dependence of nonlocal optical potentials

Science.gov (United States)

Lovell, A. E.; Bacq, P.-L.; Capel, P.; Nunes, F. M.; Titus, L. J.

2017-11-01

Recently, a variety of studies have shown the importance of including nonlocality in the description of reactions. The goal of this work is to revisit the phenomenological approach to determining nonlocal optical potentials from elastic scattering. We perform a χ2 analysis of neutron elastic scattering data off 40Ca, 90Zr, and 208Pb at energies E ≈5 -40 MeV, assuming a Perey and Buck [Nucl. Phys. 32, 353 (1962), 10.1016/0029-5582(62)90345-0] or Tian et al. [Int. J. Mod. Phys. E 24, 1550006 (2015), 10.1142/S0218301315500068] nonlocal form for the optical potential. We introduce energy and asymmetry dependencies in the imaginary part of the potential and refit the data to obtain a global parametrization. Independently of the starting point in the minimization procedure, an energy dependence in the imaginary depth is required for a good description of the data across the included energy range. We present two parametrizations, both of which represent an improvement over the original potentials for the fitted nuclei as well as for other nuclei not included in our fit. Our results show that, even when including the standard Gaussian nonlocality in optical potentials, a significant energy dependence is required to describe elastic-scattering data.

Value of Exercise ECG for Risk Stratification in Suspected or Known CAD in the Era of Advanced Imaging Technologies.

Science.gov (United States)

Bourque, Jamieson M; Beller, George A

2015-11-01

Exercise stress electrocardiography (ExECG) is underutilized as the initial test modality in patients with interpretable electrocardiograms who are able to exercise. Although stress myocardial imaging techniques provide valuable diagnostic and prognostic information, variables derived from ExECG can yield substantial data for risk stratification, either supplementary to imaging variables or without concurrent imaging. In addition to exercise-induced ischemic ST-segment depression, such markers as ST-segment elevation in lead aVR, abnormal heart rate recovery post-exercise, failure to achieve target heart rate, and poor exercise capacity improve risk stratification of ExECG. For example, patients achieving ≥10 metabolic equivalents on ExECG have a very low prevalence of inducible ischemia and an excellent prognosis. In contrast, cardiac imaging techniques add diagnostic and prognostic value in higher-risk populations (e.g., poor functional capacity, diabetes, or chronic kidney disease). Optimal test selection for symptomatic patients with suspected coronary artery disease requires a patient-centered approach factoring in the risk/benefit ratio and cost-effectiveness. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Similarity rules of thermal stratification phenomena for water and sodium

International Nuclear Information System (INIS)

Ohtsuka, M.; Ikeda, T.; Yamakawa, M.; Shibata, Y.; Moriya, S.; Ushijima, S.; Fujimoto, K.

1988-01-01

Similarity rules for thermal stratification phenomena were studied using sodium and water experiments with scaled cylindrical vessels. The vessel dimensions were identical to focus on the effect of differences in fluid properties upon the phenomena. Comparisons of test results between sodium and water elucidated similar and dissimilar characteristics for thermal stratification phenomena which appeared in the scaled vessels. Results were as follows: (1) The dimensionless upward velocity of the thermal stratification interface was proportional to Ri -0.74 for water and sodium during the period when the buoyancy effect was dominant. (2) Dimensionless temperature transient rate at the outlet slit decreased with Ri for sodium and remained constant for water where Ri>0.2. The applicability of the scaled test results to an actual power plant was also studied by using multi-dimensional numerical analysis which was verified by the water and sodium experiments. Water experiments could simulate liquid metal fast breeder reactor flows more accurately than sodium experiments for dimensionless temperature gradient at the thermal stratification interface and dimensionless temperature transient rate at the intermediate heat exchanger inlet

Global potential energy surface of ground state singlet spin O4

Science.gov (United States)

Mankodi, Tapan K.; Bhandarkar, Upendra V.; Puranik, Bhalchandra P.

2018-02-01

A new global potential energy for the singlet spin state O4 system is reported using CASPT2/aug-cc-pVTZ ab initio calculations. The geometries for the six-dimensional surface are constructed using a novel point generation scheme that employs randomly generated configurations based on the beta distribution. The advantage of this scheme is apparent in the reduction of the number of required geometries for a reasonably accurate potential energy surface (PES) and the consequent decrease in the overall computational effort. The reported surface matches well with the recently published singlet surface by Paukku et al. [J. Chem. Phys. 147, 034301 (2017)]. In addition to the O4 PES, the ground state N4 PES is also constructed using the point generation scheme and compared with the existing PES [Y. Paukku et al., J. Chem. Phys. 139, 044309 (2013)]. The singlet surface is constructed with the aim of studying high energy O2-O2 collisions and predicting collision induced dissociation cross section to be used in simulating non-equilibrium aerothermodynamic flows.

Energy intensities: Prospects and potential

International Nuclear Information System (INIS)

Anon.

1992-01-01

In the previous chapter, the author described how rising activity levels and structural change are pushing toward higher energy use in many sectors and regions, especially in the developing countries. The extent to which more activity leads to greater energy use will depend on the energy intensity of end-use activities. In this chapter, the author presents an overview of the potential for intensity reductions in each sector over the next 10-20 years. It is not the author's intent to describe in detail the various technologies that could be employed to improve energy efficiency, which has been done by others (see, for example, Lovins ampersand Lovins, 1991; Goldembert et al., 1987). Rather, he discusses the key factors that will shape future energy intensities in different parts of the world, and gives a sense for the changes that could be attained if greater attention were given to accelerate efficiency improvement. The prospects for energy intensities, and the potential for reduction, vary among sectors and parts of the world. In the majority of cases, intensities are tending to decline as new equipment and facilities come into use and improvements are made on existing stocks. The effect of stock turnover will be especially strong in the developing countries, where stocks are growing at a rapid pace, and the Former East Bloc, where much of the existing industrial plant will eventually be retired and replaced with more modern facilities. While reductions in energy intensity are likely in most areas, there is a large divergence between the technical and economic potential for reducing energy intensities and the direction in which present trends are moving. In the next chapter, the author presents scenarios that illustrate where trends are pointing, and what could be achieved if improving energy efficiency were a focus of public policies. 53 refs., 4 figs., 2 tabs

Transformation between divacancy defects induced by an energy pulse in graphene.

Science.gov (United States)

Xia, Jun; Liu, XiaoYi; Zhou, Wei; Wang, FengChao; Wu, HengAn

2016-07-08

The mutual transformations among the four typical divacancy defects induced by a high-energy pulse were studied via molecular dynamics simulation. Our study revealed all six possible mutual transformations and found that defects transformed by absorbing energy to overcome the energy barrier with bonding, debonding, and bond rotations. The reversibility of defect transformations was also investigated by potential energy analysis. The energy difference was found to greatly influence the transformation reversibility. The direct transformation path was irreversible if the energy difference was too large. We also studied the correlation between the transformation probability and the input energy. It was found that the transformation probability had a local maxima at an optimal input energy. The introduction of defects and their structural evolutions are important for tailoring the exceptional properties and thereby performances of graphene-based devices, such as nanoporous membranes for the filtration and desalination of water.

Ventricular repolarization measures for arrhythmic risk stratification

Institute of Scientific and Technical Information of China (English)

Francesco Monitillo; Marta Leone; Caterina Rizzo; Andrea Passantino; Massimo Iacoviello

2016-01-01

Ventricular repolarization is a complex electrical phenomenon which represents a crucial stage in electrical cardiac activity. It is expressed on the surface electrocardiogram by the interval between the start of the QRS complex and the end of the T wave or U wave(QT). Several physiological, pathological and iatrogenic factors can influence ventricular repolarization. It has been demonstrated that small perturbations in this process can be a potential trigger of malignant arrhythmias, therefore the analysis of ventricular repolarization represents an interesting tool to implement risk stratification of arrhythmic events in different clinical settings. The aim of this review is to critically revise the traditional methods of static analysis of ventricular repolarization as well as those for dynamic evaluation, their prognostic significance and the possible application in daily clinical practice.

Value of planar 201Tl imaging in risk stratification of patients recovering from acute myocardial infarction

International Nuclear Information System (INIS)

Gibson, R.S.; Watson, D.D.

1991-01-01

Although exercise ECG testing has been shown to have important prognostic value after acute myocardial infarction, exercise 201Tl scintigraphy offers several potential advantages, including: (1) increased sensitivity for detecting residual myocardial ischemia; (2) the ability to localize ischemia to a specific area or areas subtended by a specific coronary artery; (3) the ability to identify exercise-induced left ventricular dysfunction, which is manifested by increased lung uptake or transient left ventricular dilation; and (4) more reliable risk stratification of individual patients. The more optimal prognostic efficiency of 201Tl scintigraphy partially results from the fact that the error rate in falsely classifying patients as low risk is significantly smaller with 201Tl scintigraphy than with stress ECG. Because of these substantial advantages, there seems to be adequate rationale for recommending exercise perfusion imaging rather than exercise ECG alone as the preferred method for evaluating mortality and morbidity risks after acute myocardial infarction

The bio-optical properties of CDOM as descriptor of lake stratification.

Science.gov (United States)

Bracchini, Luca; Dattilo, Arduino Massimo; Hull, Vincent; Loiselle, Steven Arthur; Martini, Silvia; Rossi, Claudio; Santinelli, Chiara; Seritti, Alfredo

2006-11-01

Multivariate statistical techniques are used to demonstrate the fundamental role of CDOM optical properties in the description of water masses during the summer stratification of a deep lake. PC1 was linked with dissolved species and PC2 with suspended particles. In the first principal component that the role of CDOM bio-optical properties give a better description of the stratification of the Salto Lake with respect to temperature. The proposed multivariate approach can be used for the analysis of different stratified aquatic ecosystems in relation to interaction between bio-optical properties and stratification of the water body.

Experimental study on the fluid stratification mechanism in the density lock

International Nuclear Information System (INIS)

Gu Haifeng; Yan Changqi; Sun Licheng

2009-01-01

Visualized experiments were conducted on the forming process of stratification between hot and cold fluids in three tubes with different diameters. The results show that the working fluids were divided into three layers from top to bottom: convective, interfacial, and constant temperature layers. The working fluid in the convective layer always retains the property of a high rate of temperature increase. The rate of temperature increase in the interfacial layer gradually decreased from top to bottom and was less than that in the convective layer. The working fluid temperature in the constant-temperature layer remained stable. Based on the experimental study, we built a simplified theoretical model and analyzed the stratification mechanism. The results indicate the following stratification mechanism: because of the existence of the transition points in the heat transfer modes, the differences in the rates of temperature increase appear. These differences result in the appearance of fluid stratification. In addition, research on the process of stratification under different conditions tells us that the structure of the density lock influences the position of the transition point. The density lock with a structure of variable cross-sectional grids can effectively control the position of the transition points of the heat transfer modes. (author)

Integrated collector storage solar water heater: Temperature stratification

International Nuclear Information System (INIS)

Garnier, C.; Currie, J.; Muneer, T.

2009-01-01

An analysis of the temperature stratification inside an Integrated Collector Storage Solar Water Heater (ICS-SWH) was carried out. The system takes the form of a rectangular-shaped box incorporating the solar collector and storage tank into a single unit and was optimised for simulation in Scottish weather conditions. A 3-month experimental study on the ICS-SWH was undertaken in order to provide empirical data for comparison with the computed results. Using a previously developed macro model; a number of improvements were made. The initial macro model was able to generate corresponding water bulk temperature in the collector with a given hourly incident solar radiation, ambient temperature and inlet water temperature and therefore able to predict ICS-SWH performance. The new model was able to compute the bulk water temperature variation in different SWH collectors for a given aspect ratio and the water temperature along the height of the collector (temperature stratification). Computed longitudinal temperature stratification results obtained were found to be in close agreement with the experimental data.

Exploring the Potential Impact of Greenland Meltwater on Stratification, Photosynthetically Active Radiation, and Primary Production in the Labrador Sea

Science.gov (United States)

Oliver, Hilde; Luo, Hao; Castelao, Renato M.; van Dijken, Gert L.; Mattingly, Kyle S.; Rosen, Joshua J.; Mote, Thomas L.; Arrigo, Kevin R.; Rennermalm, Åsa K.; Tedesco, Marco; Yager, Patricia L.

2018-04-01

In July 2012, the surface of the Greenland Ice Sheet (GrIS) melted to an extent unprecedented over the last 100 years; we questioned the potential for such an extreme melt event to impact marine phytoplankton offshore. We hypothesized that stratification from meltwater could reduce light limitation for phytoplankton, and used a suite of numerical models to quantify the impact for 2003-2012. Because much of the 2012 meltwater discharged from southern Greenland, our study focused on the southwestern and southeastern coasts of Greenland, and the Labrador Sea. A 1-D phytoplankton model used output from a Regional Ocean Modeling System (ROMS) coupled with a Regional Climate Model and a hydrological model of meltwater from runoff sources on the ice sheet, peripheral glaciers, and tundra. ROMS was run with and without meltwater to test the sensitivity of phytoplankton photosynthetic rates to the meltwater input. With meltwater, the pycnocline was shallower during late summer and early fall and thus light limitation on photosynthesis was reduced. Averaged over all years, added meltwater had the potential to increase gross primary production by 3-12% in the summer (July-August), and 13-60% in the fall (September-October). This meltwater effect was amplified when light was more limiting, and thus was greatest in the fall, under cloudier conditions, with higher self-shading, and with more light-sensitive phytoplankton groups. As the GrIS melt is projected to increase, late summer primary production in this region has the potential to increase as well, which could constitute an important biosphere response to high-latitude climate change.

Rotating compressible fluids under strong stratification

Czech Academy of Sciences Publication Activity Database

Feireisl, Eduard; Lu, Y.; Novotný, A.

2014-01-01

Roč. 19, October (2014), s. 11-18 ISSN 1468-1218 Keywords : rotating fluid * compressible Navier-Stokes * strong stratification Subject RIV: BA - General Mathematics Impact factor: 2.519, year: 2014 http://www.sciencedirect.com/science/article/pii/S1468121814000212#

Combustion stratification study of partially premixed combustion using Fourier transform analysis of OH* chemiluminescence images

KAUST Repository

Izadi Najafabadi, Mohammad

2017-11-06

A relatively high level of stratification (qualitatively: lack of homogeneity) is one of the main advantages of partially premixed combustion over the homogeneous charge compression ignition concept. Stratification can smooth the heat release rate and improve the controllability of combustion. In order to compare stratification levels of different partially premixed combustion strategies or other combustion concepts, an objective and meaningful definition of “stratification level” is required. Such a definition is currently lacking; qualitative/quantitative definitions in the literature cannot properly distinguish various levels of stratification. The main purpose of this study is to objectively define combustion stratification (not to be confused with fuel stratification) based on high-speed OH* chemiluminescence imaging, which is assumed to provide spatial information regarding heat release. Stratification essentially being equivalent to spatial structure, we base our definition on two-dimensional Fourier transforms of photographs of OH* chemiluminescence. A light-duty optical diesel engine has been used to perform the OH* bandpass imaging on. Four experimental points are evaluated, with injection timings in the homogeneous regime as well as in the stratified partially premixed combustion regime. Two-dimensional Fourier transforms translate these chemiluminescence images into a range of spatial frequencies. The frequency information is used to define combustion stratification, using a novel normalization procedure. The results indicate that this new definition, based on Fourier analysis of OH* bandpass images, overcomes the drawbacks of previous definitions used in the literature and is a promising method to compare the level of combustion stratification between different experiments.

Forecasting of Energy Expenditure of Induced Seismicity with Use of Artificial Neural Network

Science.gov (United States)

Cichy, Tomasz; Banka, Piotr

2017-12-01

Coal mining in many Polish mines in the Upper Silesian Coal Basin is accompanied by high levels of induced seismicity. In mining plants, the methods of shock monitoring are improved, allowing for more accurate localization of the occurring phenomena and determining their seismic energy. Equally important is the development of ways of forecasting seismic hazards that may occur while implementing mine design projects. These methods, depending on the length of time for which the forecasts are made, can be divided into: longterm, medium-term, short-term and so-called alarm. Long-term forecasts are particularly useful for the design of seam exploitations. The paper presents a method of predicting changes in energy expenditure of shock using a properly trained artificial neural network. This method allows to make long-term forecasts at the stage of the mine’s exploitation design, thus enabling the mining work plans to be reviewed to minimize the potential for tremors. The information given at the input of the neural network is indicative of the specific energy changes of the elastic deformation occurring in the selected, thick, resistant rock layers (tremor-prone layers). Energy changes, taking place in one or more tremor-prone layers are considered. These indicators describe only the specific energy changes of the elastic deformation accumulating in the rock as a consequence of the mining operation, but does not determine the amount of energy released during the destruction of a given volume of rock. In this process, the potential energy of elastic strain transforms into other, non-measurable energy types, including the seismic energy of recorded tremors. In this way, potential energy changes affect the observed induced seismicity. The parameters used are characterized by increases (declines) of specific energy with separation to occur before the hypothetical destruction of the rock and after it. Additional input information is an index characterizing the rate of

Fossil energy savings potential of sugar cane bio-energy systems

DEFF Research Database (Denmark)

Nguyen, Thu Lan T; Hermansen, John Erik; Sagisaka, Masayuki

2009-01-01

One important rationale for bio-energy systems is their potential to save fossil energy. Converting a conventional sugar mill into a bio-energy process plant would contribute to fossil energy savings via the extraction of renewable electricity and ethanol substituting for fossil electricity...... and gasoline, respectively. This paper takes a closer look at the Thai sugar industry and examines two practical approaches that will enhance fossil energy savings. The first one addresses an efficient extraction of energy in the form of electricity from the excess bagasse and cane trash. The second while...... proposing to convert molasses or sugar cane to ethanol stresses the use of bagasse as well as distillery spent wash to replace coal in meeting ethanol plants' energy needs. The savings potential achieved with extracting ethanol from surplus sugar versus current practice in sugar industry in Thailand amounts...

Acoustic study of stratification region of melts in In-Se system

International Nuclear Information System (INIS)

Glazov, V.M.; Kim, S.G.; Nurova, K.B.

1989-01-01

Stratification region of melts in In-Se system was studied in detail with the use of the method of measuring ultrasound velocity. The curve, limiting the region of stratification into two liquid solutions was plotted. It is shown that the curve is characterized as symmetrical finodal

Investigation of the Solvis stratification inlet pipe for solar tanks

DEFF Research Database (Denmark)

Andersen, Elsa; Jordan, Ulrike; Shah, Louise Jivan

2004-01-01

Since the 1960’ties the influence of the thermal stratification in hot water tanks on the thermal performance of solar heating systems has been studied intensively. It was found, that the thermal performance of a solar heating system is increasing for increasing thermal stratification in the hot...... water tank. The temperature of the storage water heated by the solar collector loop usually varies strongly during the day. In order to reach a good thermal stratification in the tank, different types of pipes, plates, diffusers and other devices have been investigated in the past (e.g. Loehrke, 1979...... conditions. Temperature measurements were carried out and an optical method called Particle Image Velocimetry (PIV) was used to visualize the flow around the flaps....

Influence of upper-ocean stratification on tropical cyclone-induced surface cooling in the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Neetu, S.; Lengaigne, M.; Vincent, E.M.; Vialard, J.; Madec, G.; Samson, G.; RameshKumar, M.R.; Durand, F.

homeless people and over $10 billion in economic losses [Webster, 2008; McPhaden et al., 2009]. It is therefore of utter practical importance to identify the key factors that control TC intensity in this region. Uncertainties in TC intensity forecasts... stratification on TC intensification has recently been illustrated within the BoB [Ali et al., 2007]. In the case of TC Nargis, Yu and McPhaden [2011] highlighted the apparent connection between a high temperature, a low salinity front, and the TC intensity...

Workshop on induced Seismicity due to fluid injection/production from Energy-Related Applications

Energy Technology Data Exchange (ETDEWEB)

Majer, E.L.; Asanuma, Hiroshi; Rueter, Horst; Stump, Brian; Segall, Paul; Zoback, Mark; Nelson, Jim; Frohlich, Cliff; Rutledge, Jim; Gritto, Roland; Baria, Roy; Hickman, Steve; McGarr, Art; Ellsworth, Bill; Lockner, Dave; Oppenheimer, David; Henning, Peter; Rosca, Anca; Hornby, Brian; Wang, Herb; Beeler, Nick; Ghassemi, Ahmad; Walters, Mark; Robertson-Tait, Ann; Dracos, Peter; Fehler, Mike; Abou-Sayed, Ahmed; Ake, Jon; Vorobiev, Oleg; Julian, Bruce

2011-04-01

Geothermal energy, carbon sequestration, and enhanced oil and gas recovery have a clear role in U.S. energy policy, both in securing cost-effective energy and reducing atmospheric CO{sub 2} accumulations. Recent publicity surrounding induced seismicity at several geothermal and oil and gas sites points out the need to develop improved standards and practices to avoid issues that may unduly inhibit or stop the above technologies from fulfilling their full potential. It is critical that policy makers and the general community be assured that EGS, CO{sub 2} sequestration, enhanced oil/gas recovery, and other technologies relying on fluid injections, will be designed to reduce induced seismicity to an acceptable level, and be developed in a safe and cost-effective manner. Induced seismicity is not new - it has occurred as part of many different energy and industrial applications (reservoir impoundment, mining, oil recovery, construction, waste disposal, conventional geothermal). With proper study/research and engineering controls, induced seismicity should eventually allow safe and cost-effective implementation of any of these technologies. In addition, microseismicity is now being used as a remote sensing tool for understanding and measuring the success of injecting fluid into the subsurface in a variety of applications, including the enhancement of formation permeability through fracture creation/reactivation, tracking fluid migration and storage, and physics associated with stress redistribution. This potential problem was envisaged in 2004 following observed seismicity at several EGS sites, a study was implemented by DOE to produce a white paper and a protocol (Majer et al 2008) to help potential investors. Recently, however, there have been a significant number of adverse comments by the press regarding induced seismicity which could adversely affect the development of the energy sector in the USA. Therefore, in order to identify critical technology and research

Nuclear three-body problem and energy-dependent potentials

International Nuclear Information System (INIS)

Abdurakhmanov, A.; Akhmadkhodzhaev, B.; Zubarev, A.L.; Irgaziev, B.F.

1985-01-01

Energy-dependent potentials in the three-body problem are being considered. Three-particle equations for the case of pairing energy-dependent potentials are generalized and the problems related to this ambiguous generalization are investigated. In terms of the equations obtained the tritium binding energy and vertex coupling constants (Tdn) and (Tdν) are evaluated. The binding energy and, especially, coupling constants are shown to be sensitive to a shape of the energy-dependent potential

Strongly enhanced colorectal cancer risk stratification by combining family history and genetic risk score

Directory of Open Access Journals (Sweden)

Weigl K

2018-01-01

Full Text Available Korbinian Weigl,1,2 Jenny Chang-Claude,3,4 Phillip Knebel,5 Li Hsu,6 Michael Hoffmeister,1 Hermann Brenner1,2,7 1Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ, Heidelberg, 2German Cancer Consortium (DKTK, German Cancer Research Center (DKFZ, Heidelberg, 3Unit of Genetic Epidemiology, German Cancer Research Center (DKFZ, Heidelberg, 4University Cancer Center Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, 5Department for General, Visceral and Transplantation Surgery, University Heidelberg, Heidelberg, Germany; 6Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA; 7Division of Preventive Oncology, German Cancer Research Center (DKFZ and National Center for Tumor Diseases (NCT, Heidelberg, Germany Background and aim: Family history (FH and genetic risk scores (GRSs are increasingly used for risk stratification for colorectal cancer (CRC screening. However, they were mostly considered alternatively rather than jointly. The aim of this study was to assess the potential of individual and joint risk stratification for CRC by FH and GRS.Patients and methods: A GRS was built based on the number of risk alleles in 53 previously identified single-nucleotide polymorphisms among 2,363 patients with a first diagnosis of CRC and 2,198 controls in DACHS [colorectal cancer: chances for prevention through screening], a population-based case-control study in Germany. Associations between GRS and FH with CRC risk were quantified by multiple logistic regression.Results: A total of 316 cases (13.4% and 214 controls (9.7% had a first-degree relative (FDR with CRC (adjusted odds ratio [aOR] 1.86, 95% CI 1.52–2.29. A GRS in the highest decile was associated with a 3.0-fold increased risk of CRC (aOR 3.00, 95% CI 2.24–4.02 compared with the lowest decile. This association was tentatively more pronounced in older age groups. FH and GRS were essentially unrelated, and their

Temperature Stratification in a Cryogenic Fuel Tank

Data.gov (United States)

National Aeronautics and Space Administration — A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It...

Correction of population stratification in large multi-ethnic association studies.

Directory of Open Access Journals (Sweden)

David Serre

2008-01-01

Full Text Available The vast majority of genetic risk factors for complex diseases have, taken individually, a small effect on the end phenotype. Population-based association studies therefore need very large sample sizes to detect significant differences between affected and non-affected individuals. Including thousands of affected individuals in a study requires recruitment in numerous centers, possibly from different geographic regions. Unfortunately such a recruitment strategy is likely to complicate the study design and to generate concerns regarding population stratification.We analyzed 9,751 individuals representing three main ethnic groups - Europeans, Arabs and South Asians - that had been enrolled from 154 centers involving 52 countries for a global case/control study of acute myocardial infarction. All individuals were genotyped at 103 candidate genes using 1,536 SNPs selected with a tagging strategy that captures most of the genetic diversity in different populations. We show that relying solely on self-reported ethnicity is not sufficient to exclude population stratification and we present additional methods to identify and correct for stratification.Our results highlight the importance of carefully addressing population stratification and of carefully "cleaning" the sample prior to analyses to obtain stronger signals of association and to avoid spurious results.

Study of thermal and hydraulic efficiency of supersonic tube of temperature stratification

Science.gov (United States)

Tsynaeva, Anna A.; Nikitin, Maxim N.; Tsynaeva, Ekaterina A.

2017-10-01

Efficiency of supersonic pipe for temperature stratification with finned subsonic surface of heat transfer is the major of this paper. Thermal and hydraulic analyses of this pipe were conducted to asses effects from installation of longitudinal rectangular and parabolic fins as well as studs of cylindrical, rectangular and parabolic profiles. The analysis was performed based on refined empirical equations of similarity, dedicated to heat transfer of high-speed gas flow with plain wall, and Kármán equation with Nikuradze constants. Results revealed cylindrical studs (with height-to-diameter ratio of 5:1) to be 1.5 times more efficient than rectangular fins of the same height. At the same time rectangular fins (with height-to-thickness ratio of 5:1) were tend to enhance heat transfer rate up to 2.67 times compared to bare walls from subsonic side of the pipe. Longitudinal parabolic fins have minuscule effect on combined efficiency of considered pipe since extra head losses void any gain of heat transfer. Obtained results provide perspective of increasing efficiency of supersonic tube for temperature stratification. This significantly broadens device applicability in thermostatting systems for equipment, cooling systems for energy converting machinery, turbine blades and aerotechnics.

On Stratification in Changing Higher Education: The "Analysis of Status" Revisited

Science.gov (United States)

Bloch, Roland; Mitterle, Alexander

2017-01-01

This article seeks to shed light on current dynamics of stratification in changing higher education and proposes an analytical perspective to account for these dynamics based on Martin Trow's work on "the analysis of status." In research on higher education, the term "stratification" is generally understood as a metaphor that…

Steam systems in industry: Energy use and energy efficiency improvement potentials

International Nuclear Information System (INIS)

Einstein, Dan; Worrell, Ernst; Khrushch, Marta

2001-01-01

Steam systems are a part of almost every major industrial process today. Thirty-seven percent of the fossil fuel burned in US industry is burned to produce steam. In this paper we will establish baseline energy consumption for steam systems. Based on a detailed analysis of boiler energy use we estimate current energy use in boilers in U.S. industry at 6.1 Quads (6.4 EJ), emitting almost 66 MtC in CO(sub 2) emissions. We will discuss fuels used and boiler size distribution. We also describe potential savings measures, and estimate the economic energy savings potential in U.S. industry (i.e. having payback period of 3 years or less). We estimate the nationwide economic potential, based on the evaluation of 16 individual measures in steam generation and distribution. The analysis excludes the efficient use of steam and increased heat recovery. Based on the analysis we estimate the economic potential at 18-20% of total boiler energy use, resulting in energy savings approximately 1120-1190 TBtu ( 1180-1260 PJ). This results in a reduction of CO(sub 2) emissions equivalent to 12-13 MtC

Canadian wind energy technical and market potential

International Nuclear Information System (INIS)

Templin, R.J.; Rangli, R.S.

1992-01-01

The current status of wind energy technology in Canada is reviewed, the technical potential of wind energy in Canada is estimated, and the economic market potential is assessed under several scenarios over about the next 25 years. The technical potential is seen to be large, with applications to water pumping on farms, the coupling of wind turbines to diesel-electric systems in remote communities where fuel costs are high, and the supply of electricity to main power grids. The main-grid application has greatest technical potential, but it cannot be economically exploited under the present utility buyback rate structure for intermittent power sources. A change in government policy toward market development of renewable energy sources, such as is already taking place in several European countries, would greatly increase market potential, decrease emissions of CO 2 and SO 2 , and benefit the Canadian wind energy industry. 2 figs., 1 tab

Energy performance contracting - energy saving potential of selected energy conservation measures (ECM)

Energy Technology Data Exchange (ETDEWEB)

Johansson, M. (Dansk Energi Analyse A/S, Frederiksberg (Denmark)); Langkilde, G.; Olesen, Bjarne W. (Technical Univ. of Denmark, ICIEE, Kgs. Lyngby (Denmark)); Moerck, O. (Cenergia Energy Consultants, Herlev (Denmark)); Sundman, O. (DONG Energy, Copenhagen (Denmark)); Engelund Thomsen, K. (Aalborg Univ., SBi, Hoersholm (Denmark))

2008-09-15

This report has been developed under the research project 'Etablering af grundlag for energitjenester i Danmark' (project number: ENS-33031-0185) under the Danish research programme - EFP. The objective of this project has been to contribute to the utilisation of the large potential for energy conservations in the building sector within the public, industry and service sectors through the development of a better basis for decision making for both the Energy Service Companies (ESCOes) and the building owners. The EU directive on Energy Service Contracting points at the buildings as the area where the biggest potential market for energy services and energy efficiency improvements are. The EFP-project has two parts: (1) A Danish part and (2) participation in the international cooperation project 'Holistic Assesment Tool-Kit on Energy Efficient Retrofit Measures for Government Buildings (EnERGo)', Annex 46 under the IEA R and D program 'Energy Conservation In Buildings And Community Systems' (ECBCS). This report describes the Danish contributions to the IEA projects subtask B, which has a primary objective to develop a database of energy conservation measures (ECM) with descriptions and performance characteristics of these. (au)

Energy performance contracting - energy saving potential of selected energy conservation measures (ECM)

Energy Technology Data Exchange (ETDEWEB)

Johansson, M [Dansk Energi Analyse A/S, Frederiksberg (Denmark); Langkilde, G; Olesen, Bjarne W [Technical Univ. of Denmark, ICIEE, Kgs. Lyngby (Denmark); Moerck, O [Cenergia Energy Consultants, Herlev (Denmark); Sundman, O [DONG Energy, Copenhagen (Denmark); Engelund Thomsen, K [Aalborg Univ., SBi, Hoersholm (Denmark)

2008-09-15

This report has been developed under the research project 'Etablering af grundlag for energitjenester i Danmark' (project number: ENS-33031-0185) under the Danish research programme - EFP. The objective of this project has been to contribute to the utilisation of the large potential for energy conservations in the building sector within the public, industry and service sectors through the development of a better basis for decision making for both the Energy Service Companies (ESCOes) and the building owners. The EU directive on Energy Service Contracting points at the buildings as the area where the biggest potential market for energy services and energy efficiency improvements are. The EFP-project has two parts: (1) A Danish part and (2) participation in the international cooperation project 'Holistic Assesment Tool-Kit on Energy Efficient Retrofit Measures for Government Buildings (EnERGo)', Annex 46 under the IEA R and D program 'Energy Conservation In Buildings And Community Systems' (ECBCS). This report describes the Danish contributions to the IEA projects subtask B, which has a primary objective to develop a database of energy conservation measures (ECM) with descriptions and performance characteristics of these. (au)

Spatial mapping of renewable energy potential

Energy Technology Data Exchange (ETDEWEB)

Ramachandra, T.V. [Centre for Sustainable Technologies, Indian Institute of Science, Bangalore (India); Energy Research Group, CES RNO 215, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012 (India); Shruthi, B.V. [Energy Research Group, CES RNO 215, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012 (India)

2007-09-15

An energy resource that is renewed by nature and whose supply is not affected by the rate of consumption is often termed as renewable energy. The need to search for renewable, alternate and non-polluting sources of energy assumes top priority for self-reliance in the regional energy supply. This demands an estimation of available energy resources spatially to evolve better management strategies for ensuring sustainability of resources. The spatial mapping of availability and demand of energy resources would help in the integrated regional energy planning through an appropriate energy supply-demand matching. This paper discusses the application of Geographical Information System (GIS) to map the renewable energy potential talukwise in Karnataka State, India. Taluk is an administrative division in the federal set-up in India to implement developmental programmes like dissemination of biogas, improved stoves, etc. Hence, this paper focuses talukwise mapping of renewable energy (solar, wind, bioenergy and small hydroenergy) potential for Karnataka using GIS. GIS helps in spatial and temporal analyses of the resources and demand and also aids as Decision Support System while implementing location-specific renewable energy technologies. Regions suitable for tapping solar energy are mapped based on global solar radiation data, which provides a picture of the potential. Coastal taluks in Uttara Kannada have higher global solar radiation during summer (6.31 kWh/m{sup 2}), monsoon (4.16 kWh/m{sup 2}) and winter (5.48 kWh/m{sup 2}). Mapping of regions suitable for tapping wind energy has been done based on wind velocity data, and it shows that Chikkodi taluk, Belgaum district, has higher potential during summer (6.06 m/s), monsoon (8.27 m/s) and winter (5.19 m/s). Mysore district has the maximum number of small hydropower plants with a capacity of 36 MW. Talukwise computation of bioenergy availability from agricultural residue, forest, horticulture, plantation and livestock

An assessement of global energy resource economic potentials

International Nuclear Information System (INIS)

Mercure, Jean-François; Salas, Pablo

2012-01-01

This paper presents an assessment of global economic energy potentials for all major natural energy resources. This work is based on both an extensive literature review and calculations using natural resource assessment data. Economic potentials are presented in the form of cost-supply curves, in terms of energy flows for renewable energy sources, or fixed amounts for fossil and nuclear resources, with strong emphasis on uncertainty, using a consistent methodology that allow direct comparisons to be made. In order to interpolate through available resource assessment data and associated uncertainty, a theoretical framework and a computational methodology are given based on statistical properties of different types of resources, justified empirically by the data, and used throughout. This work aims to provide a global database for natural energy resources ready to integrate into models of energy systems, enabling to introduce at the same time uncertainty over natural resource assessments. The supplementary material provides theoretical details and tables of data and parameters that enable this extensive database to be adapted to a variety of energy systems modelling frameworks. -- Highlights: ► Global energy potentials for all major energy resources are reported. ► Theory and methodology for calculating economic energy potentials is given. ► An uncertainty analysis for all energy economic potentials is carried out.

RUSTEC: Greening Europe's energy supply by developing Russia's renewable energy potential

International Nuclear Information System (INIS)

Boute, Anatole; Willems, Patrick

2012-01-01

The North-West of Russia is characterized by a large renewable energy resource base in geographic proximity to the EU. At the same time, EU Member States are bound by mandatory renewable energy targets which could prove to be costly to achieve in the current budgetary context and which often face strong local opposition. Directive 2009/28/EC on Renewable Energy makes it possible for Member States to achieve their targets by importing electricity produced from renewable energy sources from non-EU countries. So far, most attention has been on the Mediterranean Solar Plan or Desertec. An EU–Russia Renewable Energy Plan or RUSTEC – being based on onshore wind/biomass/hydro energy and on-land interconnection, rather than solar power and subsea lines – could present a cost-efficient and short-term complement to Desertec. This article examines the political, geopolitical, economic, social and legal challenges and opportunities of exporting “green” energy from Russia to the EU. It argues that EU–Russian cooperation in the renewable energy field would present a win-win situation: Member States could achieve their targets on the basis of Russia's renewable energy potential, while Russia could begin to develop a national renewable energy industry without risking potential price increases for domestic consumers—a concern of great political sensitivity in Russia. - Highlights: ► Russia has a huge renewable energy potential in geographic proximity to the EU. ► This potential could help the EU decarbonize its electricity supply at least cost.► EU–Russia green energy export is a win-win situation but lacks political attention.► RUSTEC could be a short-term and cost-efficient complement to Desertec. ► RUSTEC would diversify EU energy imports/Russian exports and stimulate innovation.

Validation of Effective Models for Simulation of Thermal Stratification and Mixing Induced by Steam Injection into a Large Pool of Water

Directory of Open Access Journals (Sweden)

Hua Li

2014-01-01

Full Text Available The Effective Heat Source (EHS and Effective Momentum Source (EMS models have been proposed to predict the development of thermal stratification and mixing during a steam injection into a large pool of water. These effective models are implemented in GOTHIC software and validated against the POOLEX STB-20 and STB-21 tests and the PPOOLEX MIX-01 test. First, the EHS model is validated against STB-20 test which shows the development of thermal stratification. Different numerical schemes and grid resolutions have been tested. A 48×114 grid with second order scheme is sufficient to capture the vertical temperature distribution in the pool. Next, the EHS and EMS models are validated against STB-21 test. Effective momentum is estimated based on the water level oscillations in the blowdown pipe. An effective momentum selected within the experimental measurement uncertainty can reproduce the mixing details. Finally, the EHS-EMS models are validated against MIX-01 test which has improved space and time resolution of temperature measurements inside the blowdown pipe. Excellent agreement in averaged pool temperature and water level in the pool between the experiment and simulation has been achieved. The development of thermal stratification in the pool is also well captured in the simulation as well as the thermal behavior of the pool during the mixing phase.

Thermal stratification in storage tanks of integrated collector storage solar water heaters

International Nuclear Information System (INIS)

Oshchepkov, M.Y.; Frid, S.E.

2015-01-01

To determine the influence of the shape of the tank, the installation angle, and the magnitude of the absorbed heat flux on thermal stratification in integrated collector-storage solar water heaters, numerical simulation of thermal convection in tanks of different shapes and same volume was carried out. Idealized two-dimensional models were studied; auto model stratification profiles were obtained at the constant heat flux. The shape of the tank, the pattern of the heat flux dynamics, the adiabatic mixing on the circulation rate and the degree of stratification were shown to have significant influence. (authors)

An Improved Model of Cryogenic Propellant Stratification in a Rotating, Reduced Gravity Environment

Science.gov (United States)

Oliveira, Justin; Kirk, Daniel R.; Schallhorn, Paul A.; Piquero, Jorge L.; Campbell, Mike; Chase, Sukhdeep

2007-01-01

This paper builds on a series of analytical literature models used to predict thermal stratification within rocket propellant tanks. The primary contribution to the literature is to add the effect of tank rotation and to demonstrate the influence of rotation on stratification times and temperatures. This work also looks levels of thermal stratification for generic propellant tanks (cylindrical shapes) over a parametric range of upper-stage coast times, heating levels, rotation rates, and gravity levels.

Study on in-vessel thermohydraulics phenomena of sodium-cooled fast reactors. 3. Numerical investigation for thermal stratification phenomena in the upper plenum

International Nuclear Information System (INIS)

Muramatsu, Toshiharu; Yamaguchi, Akira

2002-06-01

A large-scale sodium-cooled fast breeder reactor in the feasibility studies on commercialized fast reactors has a feature of consideration of thorough simplified and compacted systems and components design to realize drastic economical improvements. Therefore, special attentions should be paid to thermohydraulic designs for gas entrainment behavior from free surface, flow-induced vibration of in-vessel components, thermal stratification in the plenum, thermal shock for various structures due to high-speed coolant flows, nonsymmetrical coolant flows, etc. in the reactor vessel. In-vessel thermohydraulic analyses were carried out using a multi-dimensional code AQUA to understand the thermal stratification characteristics in the upper plenum, and to investigate trade-off relations between gas entrainment and thermal stratification phenomena on in-vessel structures for the elimination of gas entrainment possibility. From the analysis, the following results were obtained. (1) Dummy plug insertion to a slit of the upper core structure is one of the effective measures to stabilize the in-vessel flow patterns and to mitigate in-vessel thermal shocks. (2) Though flow guide device such as a baffle ring attached to reactor vessel wall is an effective measure to eliminate impinging jet to dipped plate, rising characteristics of the thermal stratification interface are affected by the baffle ring devise. (3) Thermal stratification characteristics are not influenced very much by the installation of a partial inner barrel to the dipped plate, which is an effective measure to reduce the horizontal flow velocity components at free surface. (4) Labyrinth structures to the gap between the reactor vessel wall and the outer dipped plate have direct effects upon in-vessel thermal shock characteristics including thermal stratification phenomena due to the closing of flow path between the upper plenum and the free surface plenum. (author)

The potential of (waste)water as energy carrier

International Nuclear Information System (INIS)

Frijns, Jos; Hofman, Jan; Nederlof, Maarten

2013-01-01

Graphical abstract: Energy input and potential output of the Dutch communal water cycle. Highlights: ► Municipal wastewater is a large carrier of chemical and thermal energy. ► The recovery of chemical energy from wastewater can be maximised by digestion. ► The potential of thermal energy recovery from wastewater is huge. ► Underground thermal energy storage is a rapidly developing renewable energy source. - Abstract: Next to energy efficiency improvements in the water sector, there is a need for new concepts in which water is viewed as a carrier of energy. Municipal wastewater is a potential source of chemical energy, i.e. organic carbon that can be recovered as biogas in sludge digestion. The recovery of chemical energy can be maximised by up-concentration of organic carbon and maximised sludge digestion or by source separation and anaerobic treatment. Even more so, domestic wastewater is a source of thermal energy. Through warm water conservation and heat recovery, for example with shower heat exchangers, substantial amounts of energy can be saved and recovered from the water cycle. Water can also be an important renewable energy source, i.e. as underground thermal energy storage. These systems are developing rapidly in the Netherlands and their energy potential is large.

Wave Energy Potential in the Latvian EEZ

Science.gov (United States)

Beriņš, J.; Beriņš, J.; Kalnačs, J.; Kalnačs, A.

2016-06-01

The present article deals with one of the alternative forms of energy - sea wave energy potential in the Latvian Exclusice Economic Zone (EEZ). Results have been achieved using a new method - VEVPP. Calculations have been performed using the data on wave parameters over the past five years (2010-2014). We have also considered wave energy potential in the Gulf of Riga. The conclusions have been drawn on the recommended methodology for the sea wave potential and power calculations for wave-power plant pre-design stage.

Nuclear energy: potentiality and implications

International Nuclear Information System (INIS)

Bahgat, Gawdat

2008-01-01

After a discussion about a broad definition of energy security and about the main challenges facing a potential nuclear renaissance, the article analyses how the European Union and the United States have addressed these challenges. There is no doubt that nuclear power will remain an important component of global energy mix, but it should not be seen as a panacea to the flows in the global energy markets [it

Squamous Cell Carcinoma Antigen-encoding Genes SERPINB3/B4 as Potentially Useful Markers for the Stratification of HNSCC Tumours.

Science.gov (United States)

Saidak, Zuzana; Morisse, Mony Chenda; Chatelain, Denis; Sauzay, Chloé; Houessinon, Aline; Guilain, Nelly; Soyez, Marion; Chauffert, Bruno; Dakpé, Stéphanie; Galmiche, Antoine

2018-03-01

The squamous cell carcinoma antigen (SCCA), encoded by the genes SERPINB3/B4, is a tumour marker produced by head and neck squamous cell carcinoma (HNSCC). We aimed to examine SERPINB3/B4 mRNA levels and its clinical significance in the therapeutic context. We retrieved mRNA expression levels, clinical, pathological and genomic data for 520 HNSCC from The Cancer Genome Atlas (TCGA). HNSCC tumours express high levels of SERPINB3/B4 mRNA. SERPINB3 expression differs depending on Human papillomavirus (HPV) infection status, primary tumour location, grade and differentiation, extension to lymph nodes and extracapsular spread. Interestingly, we observed an association between SERPINB3/B4 and the presence of tumour immune infiltrate as well as the expression of the immune checkpoint regulators PD-L1/PD-L2 that depended on HPV status. Our findings point to potential interest of SERPINB3/B4 for the stratification of HNSCC patients in the therapeutic context. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Characteristics of multiple auroral inverted-V structures and the problem of magnetospheric plasma stratification

International Nuclear Information System (INIS)

Antonova, E.E.; Stepanova, M.V.; Teltzov, M.V.; Tverskoy, B.A.

1993-01-01

The concept of hot stratification of magnetospheric plasma is presented. The stratification mechanism is based on the assumption that in the center of plasma sheet the pressure is approximately isotropic and under steady state conditions the gradient and curvature drift currents play the principal role. The number of formed structures is determined by the parameter of stratification. 7 figs., 2 tabs

Thermal stratification built up in hot water tank with different inlet stratifiers

DEFF Research Database (Denmark)

Dragsted, Janne; Furbo, Simon; Dannemand, Mark

2017-01-01

Thermal stratification in a water storage tank can strongly increase the thermal performance of solar heating systems. Thermal stratification can be built up in a storage tank during charge, if the heated water enters through an inlet stratifier. Experiments with a test tank have been carried out...... in order to elucidate how well thermal stratification is established in the tank with differently designed inlet stratifiers under different controlled laboratory conditions. The investigated inlet stratifiers are from Solvis GmbH & Co KG and EyeCular Technologies ApS. The inlet stratifier from Solvis Gmb...... for Solvis GmbH & Co KG had a better performance at 4 l/min. In the intermediate charge test the stratifier from EyeCular Technologies ApS had a better performance in terms of maintaining the thermal stratification in the storage tank while charging with a relative low temperature. [All rights reserved...

Map of decentralised energy potential based on renewable energy sources in Croatia

International Nuclear Information System (INIS)

Schneider, D. R.; Ban, M.; Duic, N.; Bogdan, Z.

2005-01-01

Although the Republic of Croatia is almost completely electrified there are still regions where electricity network is not in place or network capacity is insufficient. These regions usually include areas of special state care (underdeveloped, war-affected or depopulated areas), islands, and mountainous areas. However, they often have good renewable energy potential. Decentralised energy generation based on renewable energy sources (wind power, hydropower, solar energy, biomass) has potential to ensure energy supply to users in remote and often isolated rural areas (off-grid applications). Such applications will primarily be related to tourism business in mountainous, rural and island/coastal regions. Also, agriculture, wood-processing and food-processing industries will potentially be interested in application of decentralised energy generation systems, most likely those using biomass as fuel (for example cogeneration facilities, connected on-grid).(author)

Glacial ocean circulation and stratification explained by reduced atmospheric temperature.

Science.gov (United States)

Jansen, Malte F

2017-01-03

Earth's climate has undergone dramatic shifts between glacial and interglacial time periods, with high-latitude temperature changes on the order of 5-10 °C. These climatic shifts have been associated with major rearrangements in the deep ocean circulation and stratification, which have likely played an important role in the observed atmospheric carbon dioxide swings by affecting the partitioning of carbon between the atmosphere and the ocean. The mechanisms by which the deep ocean circulation changed, however, are still unclear and represent a major challenge to our understanding of glacial climates. This study shows that various inferred changes in the deep ocean circulation and stratification between glacial and interglacial climates can be interpreted as a direct consequence of atmospheric temperature differences. Colder atmospheric temperatures lead to increased sea ice cover and formation rate around Antarctica. The associated enhanced brine rejection leads to a strongly increased deep ocean stratification, consistent with high abyssal salinities inferred for the last glacial maximum. The increased stratification goes together with a weakening and shoaling of the interhemispheric overturning circulation, again consistent with proxy evidence for the last glacial. The shallower interhemispheric overturning circulation makes room for slowly moving water of Antarctic origin, which explains the observed middepth radiocarbon age maximum and may play an important role in ocean carbon storage.

Electrostatic potential fluctuation induced by charge discreteness in a nanoscale trench

International Nuclear Information System (INIS)

Lee, Taesang; Kim, S. S.; Jho, Y. S.; Park, Gunyoung; Chang, C. S.

2007-01-01

A simplified two-dimensional Monte Carlo simulation is performed to estimate the charging potential fluctuations caused by strong binary Coulomb interactions between discrete charged particles in nanometer scale trenches. It is found that the discrete charge effect can be an important part of the nanoscale trench research, inducing scattering of ion trajectories in a nanoscale trench by a fluctuating electric field. The effect can enhance the ion deposition on the side walls and disperse the material contact energy of the incident ions, among others

Vertical Stratification of Soil Phosphorus as a Concern for Dissolved Phosphorus Runoff in the Lake Erie Basin.

Science.gov (United States)

Baker, David B; Johnson, Laura T; Confesor, Remegio B; Crumrine, John P

2017-11-01

During the re-eutrophication of Lake Erie, dissolved reactive phosphorus (DRP) loading and concentrations to the lake have nearly doubled, while particulate phosphorus (PP) has remained relatively constant. One potential cause of increased DRP concentrations is P stratification, or the buildup of soil-test P (STP) in the upper soil layer (soil samples (0-5 or 0-2.5 cm) alongside their normal agronomic samples (0-20 cm) ( = 1758 fields). The mean STP level in the upper 2.5 cm was 55% higher than the mean of agronomic samples used for fertilizer recommendations. The amounts of stratification were highly variable and did not correlate with agronomic STPs (Spearman's = 0.039, = 0.178). Agronomic STP in 70% of the fields was within the buildup or maintenance ranges for corn ( L.) and soybeans [ (L.) Merr.] (0-46 mg kg Mehlich-3 P). The cumulative risks for DRP runoff from the large number of fields in the buildup and maintenance ranges exceeded the risks from fields above those ranges. Reducing stratification by a one-time soil inversion has the potential for larger and quicker reductions in DRP runoff risk than practices related to drawing down agronomic STP levels. Periodic soil inversion and mixing, targeted by stratified STP data, should be considered a viable practice to reduce DRP loading to Lake Erie. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Economic Stratification Differentiates Home Gardens in the Maya Village of Pomuch, Mexico

NARCIS (Netherlands)

Poot-Pool, W.S.; Wal, van der J.C.; Flores-Guido, S.; Pat-Fernández, J.M.; Esparza-Olguín, L.

2012-01-01

Economic Stratification Differentiates Home Gardens in the Maya Village of Pomuch, Mexico. In this paper, we analyze if economic stratification of peasant families in a Maya village in the Yucatán Peninsula of Mexico influences species composition and structure of home gardens. Our general

Analysis of ABC (D) stratification for screening patients with gastric cancer.

Science.gov (United States)

Kudo, Tomohiro; Kakizaki, Satoru; Sohara, Naondo; Onozato, Yasuhiro; Okamura, Shinichi; Inui, Yoshikatsu; Mori, Masatomo

2011-11-21

To evaluate the value of ABC (D) stratification [combination of serum pepsinogen and Helicobacter pylori (H. pylori) antibody] of patients with gastric cancer. Ninety-five consecutive patients with gastric cancer were enrolled into the study. The serum pepsinogen I (PG I)/pepsinogen II (PG II) and H. pylori antibody levels were measured. Patients were classified into five groups of ABC (D) stratification according to their serological status. Endoscopic findings of atrophic gastritis and histological differentiation were also analyzed in relation to the ABC (D) stratification. The mean patient age was (67.9 ± 8.9) years. Three patients (3.2%) were classified into group A, 7 patients (7.4%) into group A', 27 patients (28.4%) into group B, 54 patients (56.8%) into group C, and 4 patients (4.2%) into group D, respectively. There were only three cases in group A when the patients taking acid proton pump inhibitors and those who had undergone eradication therapy for H. pylori (group A') were excluded. These three cases had mucosal atrophy in the grey zone according to the diagnostic manual of ABC (D) stratification. Histologically, the mean age of the patients with well differentiated adenocarcinoma was significantly higher than that of the patients with poorly differentiated adenocarcinoma (P ABC (D) stratification is a good method for screening patients with gastric cancers. Endoscopy is needed for grey zone cases to check the extent of mucosal atrophy.

RANS analyses on erosion behavior of density stratification consisted of helium–air mixture gas by a low momentum vertical buoyant jet in the PANDA test facility, the third international benchmark exercise (IBE-3)

Energy Technology Data Exchange (ETDEWEB)

Abe, Satoshi, E-mail: abe.satoshi@jaea.go.jp; Ishigaki, Masahiro; Sibamoto, Yasuteru; Yonomoto, Taisuke

2015-08-15

Highlights: . • The third international benchmark exercise (IBE-3) focused on density stratification erosion by a vertical buoyant jet in the reactor containment vessel. • Two types turbulence model modification were applied in order to accurately simulate the turbulence helium transportation in the density stratification. • The analysis result in case with turbulence model modification is good agreement with the experimental data. • There is a major difference of turbulence helium–mass transportation between in case with and without the turbulence model modification. - Abstract: Density stratification in the reactor containment vessel is an important phenomenon on an issue of hydrogen safety. The Japan Atomic Energy Agency (JAEA) has started the ROSA-SA project on containment thermal hydraulics. As a part of the activity, we participated in the third international CFD benchmark exercise (IBE-3) focused on density stratification erosion by a vertical buoyant jet in containment vessel. This paper shows our approach for the IBE-3, focusing on the turbulence transport phenomena in eroding the density stratification and introducing modified turbulence models for improvement of the CFD analyses. For this analysis, we modified the CFD code OpenFOAM by using two turbulence models; the Kato and Launder modification to estimate turbulent kinetic energy production around a stagnation point, and the Katsuki model to consider turbulence damping in density stratification. As a result, the modified code predicted well the experimental data. The importance of turbulence transport modeling is also discussed using the calculation results.

RANS analyses on erosion behavior of density stratification consisted of helium–air mixture gas by a low momentum vertical buoyant jet in the PANDA test facility, the third international benchmark exercise (IBE-3)

International Nuclear Information System (INIS)

Abe, Satoshi; Ishigaki, Masahiro; Sibamoto, Yasuteru; Yonomoto, Taisuke

2015-01-01

Highlights: . • The third international benchmark exercise (IBE-3) focused on density stratification erosion by a vertical buoyant jet in the reactor containment vessel. • Two types turbulence model modification were applied in order to accurately simulate the turbulence helium transportation in the density stratification. • The analysis result in case with turbulence model modification is good agreement with the experimental data. • There is a major difference of turbulence helium–mass transportation between in case with and without the turbulence model modification. - Abstract: Density stratification in the reactor containment vessel is an important phenomenon on an issue of hydrogen safety. The Japan Atomic Energy Agency (JAEA) has started the ROSA-SA project on containment thermal hydraulics. As a part of the activity, we participated in the third international CFD benchmark exercise (IBE-3) focused on density stratification erosion by a vertical buoyant jet in containment vessel. This paper shows our approach for the IBE-3, focusing on the turbulence transport phenomena in eroding the density stratification and introducing modified turbulence models for improvement of the CFD analyses. For this analysis, we modified the CFD code OpenFOAM by using two turbulence models; the Kato and Launder modification to estimate turbulent kinetic energy production around a stagnation point, and the Katsuki model to consider turbulence damping in density stratification. As a result, the modified code predicted well the experimental data. The importance of turbulence transport modeling is also discussed using the calculation results

On the investigation of cracking in safety injection PWR lines due to thermal stratification

International Nuclear Information System (INIS)

Simos, N.; Reich, M.; Philippacopoulos, A.J.; Hartzmann, M.

1990-01-01

Circumferential cracking in injection lines as well as feedwater lines has been observed in a number of PWRs around the world while its exact cause has been continuously sought through a number of independent investigations. The comprehensive conclusion of all studies is that the primary but not the only, cause of pipe failure is the thermal stratification phenomenon that occurs in pipes experiencing temperature differentials across their cross section. This phenomenon becomes more critical when it occurs in a cyclic manner and is associated with a number of transients as well as thermal shocks during each cycle. The resulting fatigue loading mechanism and its impact on the integrity of an auxiliary injection line is the focus of the present analysis. Thermal loadings which can simulate real temperature conditions are imposed on a 3-D finite element model of a portion of an injection line that has already experienced cracking. The induced thermal stress field is utilized to obtain excessive fatigue damage in the vicinity of the observed cracks. Finally, the impact of different levels and types of stratification as well as the geometric configuration of such lines on the pipe integrity is addressed. 12 refs., 12 figs

Improving Clinical Risk Stratification at Diagnosis in Primary Prostate Cancer: A Prognostic Modelling Study.

Directory of Open Access Journals (Sweden)

Vincent J Gnanapragasam

2016-08-01

new five-stratum risk stratification system was produced, and its prognostic power was compared against the current system, with PCSM as the outcome. The results were analysed using a Cox hazards model, the log-rank test, Kaplan-Meier curves, competing-risks regression, and concordance indices. In the training set, the new risk stratification system identified distinct subgroups with different risks of PCSM in pair-wise comparison (p < 0.0001. Specifically, the new classification identified a very low-risk group (Group 1, a subgroup of intermediate-risk cancers with a low PCSM risk (Group 2, hazard ratio [HR] 1.62 [95% CI 0.96-2.75], and a subgroup of intermediate-risk cancers with an increased PCSM risk (Group 3, HR 3.35 [95% CI 2.04-5.49] (p < 0.0001. High-risk cancers were also sub-classified by the new system into subgroups with lower and higher PCSM risk: Group 4 (HR 5.03 [95% CI 3.25-7.80] and Group 5 (HR 17.28 [95% CI 11.2-26.67] (p < 0.0001, respectively. These results were recapitulated in the testing set and remained robust after inclusion of competing risks. In comparison to the current risk stratification system, the new system demonstrated improved prognostic performance, with a concordance index of 0.75 (95% CI 0.72-0.77 versus 0.69 (95% CI 0.66-0.71 (p < 0.0001. In an external cohort, the new system achieved a concordance index of 0.79 (95% CI 0.75-0.84 for predicting PCSM versus 0.66 (95% CI 0.63-0.69 (p < 0.0001 for the current NICE risk stratification system. The main limitations of the study were that it was registry based and that follow-up was relatively short.A novel and simple five-stratum risk stratification system outperforms the standard three-stratum risk stratification system in predicting the risk of PCSM at diagnosis in men with primary non-metastatic prostate cancer, even when accounting for competing risks. This model also allows delineation of new clinically relevant subgroups of men who might potentially receive more appropriate

Prodromal Parkinsonism and Neurodegenerative Risk Stratification in REM Sleep Behavior Disorder.

Science.gov (United States)

Barber, Thomas R; Lawton, Michael; Rolinski, Michal; Evetts, Samuel; Baig, Fahd; Ruffmann, Claudio; Gornall, Aimie; Klein, Johannes C; Lo, Christine; Dennis, Gary; Bandmann, Oliver; Quinnell, Timothy; Zaiwalla, Zenobia; Ben-Shlomo, Yoav; Hu, Michele T M

2017-08-01

Rapid eye movement (REM) sleep behavior disorder (RBD) is the most specific marker of prodromal alpha-synucleinopathies. We sought to delineate the baseline clinical characteristics of RBD and evaluate risk stratification models. Clinical assessments were performed in 171 RBD, 296 control, and 119 untreated Parkinson's (PD) participants. Putative risk measures were assessed as predictors of prodromal neurodegeneration, and Movement Disorders Society (MDS) criteria for prodromal PD were applied. Participants were screened for common leucine-rich repeat kinase 2 (LRRK2)/glucocerebrosidase gene (GBA) gene mutations. Compared to controls, participants with RBD had higher rates of solvent exposure, head injury, smoking, obesity, and antidepressant use. GBA mutations were more common in RBD, but no LRRK2 mutations were found. RBD participants performed significantly worse than controls on Unified Parkinson's Disease Rating Scale (UPDRS)-III, timed "get-up-and-go", Flamingo test, Sniffin Sticks, and cognitive tests and had worse measures of constipation, quality of life (QOL), and orthostatic hypotension. For all these measures except UPDRS-III, RBD and PD participants were equally impaired. Depression, anxiety, and apathy were worse in RBD compared to PD participants. Stratification of people with RBD according to antidepressant use, obesity, and age altered the odds ratio (OR) of hyposmia compared to controls from 3.4 to 45.5. 74% (95% confidence interval [CI] 66%, 80%) of RBD participants met the MDS criteria for probable prodromal Parkinson's compared to 0.3% (95% CI 0.009%, 2%) of controls. RBD are impaired across a range of clinical measures consistent with prodromal PD and suggestive of a more severe nonmotor subtype. Clinical risk stratification has the potential to select higher risk patients for neuroprotective interventions. © Sleep Research Society 2017. Published by Oxford University Press [on behalf of the Sleep Research Society].

Worldwide potential of wind energy

Energy Technology Data Exchange (ETDEWEB)

Flavin, C

1982-01-01

A well-documented discussion is presented dealing with the worldwide potential of wind energy as a source of electrical and mechanical power. It is pointed out that 2% of the solar insolation is converted to wind kinetic energy; it is constantly renewed and nondepletable. Efficiency of windmills are discussed (20 to 40%) and payback periods of less than 5 years are cited. Effects of wind velocity and site location are described. Wind pumps are reviewed and the need for wind pumps, particularly in the developing countries is stressed. The generation of electricity by windmills using small turbines is reviewed and appears promising in areas with wind velocities greater than 12 mi/hr. The development of large windmills and groups of windmills (windfarms) for large scale electrical power is discussed, illustrated, and reviewed (offshore sites included). Environmental and safety problems are considered as well as the role of electrical utilities, government support and research activities. It is concluded that the potential contribution of wind energy is immense and that mechanical windmills may become one of the most important renewable technologies. Electrical generating potential is estimated at 20 to 30% of electrical needs. International programs are discussed briefly. 57 references. (MJJ)

Simulation of atmosphere stratification in the HDR test facility with the CONTAIN code

International Nuclear Information System (INIS)

Skerlavaj, A.; Mavko, B.; Kljenak, I.

2001-01-01

The test E11.2 'Hydrogen distribution in loop flow geometry', which was performed in the Heissdampf Reaktor containment test facility in Germany, was simulated with the CONTAIN computer code. The predicted pressure history and thermal stratification are in relatively good agreement with the measurements. The compositional stratification within the containment was qualitatively well predicted, although the degree of the stratification in the dome area was slightly underestimated. The analysis of simulation results enabled a better understanding of the physical phenomena during the test.(author)

Social Stratification and Cooperative Behavior in Spatial Prisoners' Dilemma Games.

Directory of Open Access Journals (Sweden)

Peng Lu

Full Text Available It has been a long-lasting pursuit to promote cooperation, and this study aims to promote cooperation via the combination of social stratification and the spatial prisoners' dilemma game. It is previously assumed that agents share the identical payoff matrix, but the stratification or diversity exists and exerts influences in real societies. Thus, two additional classes, elites and scoundrels, derive from and coexist with the existing class, commons. Three classes have different payoff matrices. We construct a model where agents play the prisoners' dilemma game with neighbors. It indicates that stratification and temptation jointly influence cooperation. Temptation permanently reduces cooperation; elites play a positive role in promoting cooperation while scoundrels undermine it. As the temptation getting larger and larger, elites play a more and more positive and critical role while scoundrels' negative effect becomes weaker and weaker, and it is more obvious when temptation goes beyond its threshold.

World potential of renewable energies

Energy Technology Data Exchange (ETDEWEB)

Dessus, B; Devin, B; Pharabod, F

1991-07-01

A comprehensive analysis, region by region, of the actually accessible renewable energies at a given horizon, is presented. The same methodology as the one employed to derive ``proven fossil energy reserves`` from ``energy resources`` is adopted, in which resources are defined by quantitative information on physical potential, while reserves take into account technical and economical accessibility. As renewable resources are fluctuating with time and are diluted in space and not readily transportable or storeable, it is necessary to consider the presence of populations or activities near enough to be able to profit by these diluted and volatile energies.

Energy audit: potential of energy - conservation in Jordanian ceramic industry

International Nuclear Information System (INIS)

Adas, H.; Taher, A.

2005-01-01

This paper represents the findings of the preliminary energy-audits performed by the Rational Use of Energy Division at the National Energy Research Center (NERC), as well as the findings of a detailed energy-audit carried out in the largest Ceramic plant in Jordan (Jordan Ceramic industries).These studies were preceded by a survey of the ceramic factories in Jordan. The survey was carried out in 1997. The performed preliminary energy-audits showed that an average saving-potential in most of theses plants is about 25 % of the total energy-bills in these plants, which constitutes a considerable portion of the total production-cost. This fact was verified through the detailed energy-audit performed by NERC team for the largest Ceramic Plant in Jordan in June 2003, which showed an energy-saving potential of about 30 %. This saving can be achieved by some no-cost or low-cost measures, in addition to some measures that need reasonable investments with an average pay-back period of about two years. This detailed energy-audit covered electrical systems, refrigeration systems, compressed-air systems, and kilns. The results of the detailed energy-audit can be disseminated to other Ceramic plant, because of the similarity in the production process between these plants and the plant where the detailed energy-audit was carried out. (author)

Induced gravity and the attractor dynamics of dark energy/dark matter

International Nuclear Information System (INIS)

Cervantes-Cota, Jorge L.; Putter, Roland de; Linder, Eric V.

2010-01-01

Attractor solutions that give dynamical reasons for dark energy to act like the cosmological constant, or behavior close to it, are interesting possibilities to explain cosmic acceleration. Coupling the scalar field to matter or to gravity enlarges the dynamical behavior; we consider both couplings together, which can ameliorate some problems for each individually. Such theories have also been proposed in a Higgs-like fashion to induce gravity and unify dark energy and dark matter origins. We explore restrictions on such theories due to their dynamical behavior compared to observations of the cosmic expansion. Quartic potentials in particular have viable stability properties and asymptotically approach general relativity

Comparing energy levels in isotropic and anisotropic potentials

Energy Technology Data Exchange (ETDEWEB)

Pikovski, Alexander, E-mail: alexander.pikovski@colorado.edu

2015-11-06

Qualitative information about the quantized energy levels of a system can be of great value. We study the relationship between the bound-state energies of an anisotropic potential and those of its spherical average. It is shown that the two ground-state energies satisfy an inequality, and there is a similar inequality for the first excited states. - Highlights: • Quantized energy levels in an arbitrary non-central potential are studied. • We derive inequalities between energies in a potential and its spherical average. • The results hold in three and two dimensions for any ground state and, with additional symmetry requirements for the first excited state.

Comparing energy levels in isotropic and anisotropic potentials

International Nuclear Information System (INIS)

Pikovski, Alexander

2015-01-01

Qualitative information about the quantized energy levels of a system can be of great value. We study the relationship between the bound-state energies of an anisotropic potential and those of its spherical average. It is shown that the two ground-state energies satisfy an inequality, and there is a similar inequality for the first excited states. - Highlights: • Quantized energy levels in an arbitrary non-central potential are studied. • We derive inequalities between energies in a potential and its spherical average. • The results hold in three and two dimensions for any ground state and, with additional symmetry requirements for the first excited state.

Near-surface energy transfers from internal tide beams to smaller vertical scale motions

Science.gov (United States)

Chou, S.; Staquet, C.; Carter, G. S.; Luther, D. S.

2016-02-01

Mechanical energy capable of causing diapycnal mixing in the ocean is transferred to the internal wave field when barotropic tides pass over underwater topography and generate internal tides. The resulting internal tide energy is confined in vertically limited structures, or beams. As internal tide beams (ITBs) propagate through regions of non-uniform stratification in the upper ocean, wave energy can be scattered through multiple reflections and refractions, be vertically trapped, or transferred to non-tidal frequencies through different nonlinear processes. Various observations have shown that ITBs are no longer detectable in horizontal kinetic energy beyond the first surface reflection. Importantly, this implies that some of the internal tide energy no longer propagates in to the abyssal ocean and consequently will not be available to maintain the density stratification. Using the NHM, a nonlinear and nonhydrostatic model based on the MITgcm, simulations of an ITB propagating up to the sea surface are examined in order to quantify the transformation of ITB energy to other motions. We compare and contrast the transformations enabled by idealized, smoothly-varying stratification with transformations enabled by realistic stratification containing a broad-band vertical wavenumber spectrum of variations. Preliminary two-dimensional results show that scattering due to small-scale structure in realistic stratification profiles from Hawaii can lead to energy being vertically trapped near the surface. Idealized simulations of "locally" generated internal solitary waves are analyzed in terms of energy flux transfers from the ITB to solitary waves, higher harmonics, and mean flow. The amount of internal tide energy which propagates back down after near-surface reflection of the ITB in different environments is quantified.

Ion peening and stress relaxation induced by low-energy atom bombardment of covalent solids

International Nuclear Information System (INIS)

Koster, Monika; Urbassek, Herbert M.

2001-01-01

Using molecular-dynamics simulation, we study the buildup and relaxation of stress induced by low-energy (≤150 eV) atom bombardment of a target material. The effect is brought out most clearly by using an initially compressed specimen. As target material, we employ Si, based on the Tersoff potential. By varying the bond strength in the potential, we can specifically study its effect on damage production and stress changes. We find that in general, stress is relaxed by the atom bombardment; only for low bombarding energies and strong bonds, atom bombardment increases stress. We rationalize this behavior by considering the role of energized atoms and of recoil-implanted target atoms

Effects of Mixture Stratification on Combustion and Emissions of Boosted Controlled Auto-Ignition Engines

Directory of Open Access Journals (Sweden)

Jacek Hunicz

2017-12-01

Full Text Available The stratification of in-cylinder mixtures appears to be an effective method for managing the combustion process in controlled auto-ignition (CAI engines. Stratification can be achieved and controlled using various injection strategies such as split fuel injection and the introduction of a portion of fuel directly before the start of combustion. This study investigates the effect of injection timing and the amount of fuel injected for stratification on the combustion and emissions in CAI engine. The experimental research was performed on a single cylinder engine with direct gasoline injection. CAI combustion was achieved using negative valve overlap and exhaust gas trapping. The experiments were performed at constant engine fueling. Intake boost was applied to control the excess air ratio. The results show that the application of the late injection strategy has a significant effect on the heat release process. In general, the later the injection is and the more fuel is injected for stratification, the earlier the auto-ignition occurs. However, the experimental findings reveal that the effect of stratification on combustion duration is much more complex. Changes in combustion are reflected in NOX emissions. The attainable level of stratification is limited by the excessive emission of unburned hydrocarbons, CO and soot.

Zeta-function approach to Casimir energy with singular potentials

International Nuclear Information System (INIS)

Khusnutdinov, Nail R.

2006-01-01

In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed

The potential of renewable energies

International Nuclear Information System (INIS)

Glubrecht, H.

1998-01-01

If one compares the progress in research and development of renewable energy applications with the finding which has been granted to these activities during the 23 years after the first oil shock, one cannot but be very impressed. It is indicated in this paper hoe comprehensive the potential of renewable energy is. One should take into account that the methods described form a broad interdisciplinary field in contrast to fossil and nuclear technologies. From technical point of view the present and future energy demand can be met by the broad spectrum of renewable energies in combination with energy conservation. Many of these techniques are already economically competitive: solar architecture, wind energy, hydropower, low temperature heat production, photovoltaic for remote areas, various types of biomass application, geothermal energy although not exactly renewable. The future of renewable energies will depend on opening markets for these techniques

Inverse and direct transfer functions for the fatigue follow-up of piping systems submitted to stratification

International Nuclear Information System (INIS)

Guyette, M.; De Smet, M.

1995-01-01

In this paper we outline a methodology to assess the fatigue induced in piping systems submitted to thermal stratification. More specifically, the transformation from the measured outer wall temperature time histories to stress time histories in any point of the line is treated.By means of inverse transfer functions, the fluid temperature distribution is calculated from the outside wall temperatures measured in a limited number of temperature sections. Using direct transfer functions, the local stresses due to stratification may be determined as well as the pipe free curvatures and the pipe free axial strains. Using a finite beam element model of the line, the global response of the line (in terms of displacements or stresses) due to the applied curvatures, axial strains, end point displacements, internal pressure and possible contacts with the pipe environment may be determined.The method is illustrated for the surge lines of the Doel 2 and Doel 4 nuclear power plants. An excellent correlation is found between measured and calculated displacements. Typical stress time histories are shown for a plant cool down. ((orig.))

Implementing system-wide risk stratification approaches: A review of critical success and failure factors.

Science.gov (United States)

Huckel Schneider, Carmen; Gillespie, James A; Wilson, Andrew

2017-05-01

Risk stratification has become a widely used tool for linking people identified at risk of health deterioration to the most appropriate evidence-based care. This article systematically reviews recent literature to determine key factors that have been identified as critical enablers and/or barriers to successful implementation of risk stratification tools at a system level. A systematic search found 23 articles and four promising protocols for inclusion in the review, covering the use to 20 different risk stratification tools. These articles reported on only a small fraction of the risk stratification tools used in health systems; suggesting that while the development and statistical validation of risk stratification algorithms is widely reported, there has been little published evaluation of how they are implemented in real-world settings. Controlled studies provided some evidence that the use of risk stratification tools in combination with a care management plan offer patient benefits and that the use of a risk stratification tool to determine components of a care management plan may contribute to reductions in hospital readmissions, patient satisfaction and improved patient outcomes. Studies with the strongest focus on implementation used qualitative and case study methods. Among these, the literature converged on four key areas of implementation that were found to be critical for overcoming barriers to success: the engagement of clinicians and safeguarding equity, both of which address barriers of acceptance; the health system context to address administrative, political and system design barriers; and data management and integration to address logistical barriers.

Potential and barrier study. Energy efficiency in Norwegian vocational buildings; Potensial- og barrierestudie. Energieffektivisering i norske yrkesbygg

Energy Technology Data Exchange (ETDEWEB)

Boehn, Trond Ivar; Palm, Linn Therese; Bakken, Line; Nossum, Aase; Jordell, Hanne

2012-07-01

On behalf of Enova SF, Multiconsult AS and Analyse og Strategi AS conducted an analysis to identify potential and barriers related to commercial buildings energy performance. The aim of this study was to determine what is the potential for energy efficiency for Norwegian vocational buildings that distinguishes between theoretical, technical, financial and real potential. Technical potential is the percentage of the theoretical potential that is technically feasible. Economic potential is the proportion of technical potential that is economically profitable to implement. Economic potential varies with the energy price. Build a small part of the total potential in 2020. In the calculation of the real potential is taken into account induced potential in terms of that, each year, a percentage actually implementing energy conservation measures (energy efficiency ratio 2%), a percentage rehabilitating / upgrading existing buildings (rehab rate 1.5%), and that a proportion of new buildings built better than regulatory requirements (rate 10%). In real potential for energy efficiency is the proportion of the economic potential that is not natural triggered but which is limited by various barriers. In real potential also varies with energy price. Respondents in our study is particularly concerned with the economic barriers, and least concerned the technical barriers. Attitudes and knowledge barriers are also very important. Lack of knowledge the effects and benefits of energy efficiency means that negative attitudes persist and that myths about the lack of profitability continues to exist. Many believe this is due to lack the knowledge and can be the cause of other types of barriers such as economic barriers. It has been analyzed which part of the real potential bounded by the barriers, and which type of institutions in society that can reduce these barriers with various categories of instrument. Main barriers for existing buildings practical barriers, economic barriers and

Natural gas decompression energy recovery: Energy savings potential in Italy

International Nuclear Information System (INIS)

Piatti, A.; Piemonte, C.; Rampini, E.; Vatrano, F.; Techint SpA, Milan; ENEA, Rome

1992-01-01

This paper surveyed the natural gas distribution systems employed in the Italian civil, industrial and thermoelectric sectors to identify those installations which can make use of gas decompression energy recovery systems (consisting of turbo-expanders or alternative expanders) to economically generate electric power. Estimates were then made of the total amount of potential energy savings. The study considered as eligible for energy savings interventions only those plants with a greater than 5,000 standard cubic meter per hour plant capacity. It was evaluated that, with suitable decompression equipment installed at 50 key installations (33 civil, 15 industrial), about 200 GWh of power could be produced annually, representing potential savings of about 22,000 petroleum equivalent tonnes of energy. A comparative analysis was done on three investment alternatives involving inputs of varying amounts of Government financial assistance

Unification of favourable intermediate-, unfavourable intermediate-, and very high-risk stratification criteria for prostate cancer.

Science.gov (United States)

Zumsteg, Zachary S; Zelefsky, Michael J; Woo, Kaitlin M; Spratt, Daniel E; Kollmeier, Marisa A; McBride, Sean; Pei, Xin; Sandler, Howard M; Zhang, Zhigang

2017-11-01

To improve on the existing risk-stratification systems for prostate cancer. This was a retrospective investigation including 2 248 patients undergoing dose-escalated external beam radiotherapy (EBRT) at a single institution. We separated National Comprehensive Cancer Network (NCCN) intermediate-risk prostate cancer into 'favourable' and 'unfavourable' groups based on primary Gleason pattern, percentage of positive biopsy cores (PPBC), and number of NCCN intermediate-risk factors. Similarly, NCCN high-risk prostate cancer was stratified into 'standard' and 'very high-risk' groups based on primary Gleason pattern, PPBC, number of NCCN high-risk factors, and stage T3b-T4 disease. Patients with unfavourable-intermediate-risk (UIR) prostate cancer had significantly inferior prostate-specific antigen relapse-free survival (PSA-RFS, P prostate cancer-specific mortality (PCSM, P prostate cancer. Similarly, patients with very high-risk (VHR) prostate cancer had significantly worse PSA-RFS (P prostate cancer. Moreover, patients with FIR and low-risk prostate cancer had similar outcomes, as did patients with UIR and SHR prostate cancer. Consequently, we propose the following risk-stratification system: Group 1, low risk and FIR; Group 2, UIR and SHR; and Group 3, VHR. These groups have markedly different outcomes, with 8-year distant metastasis rates of 3%, 9%, and 29% (P < 0.001) for Groups 1, 2, and 3, respectively, and 8-year PCSM of 1%, 4%, and 13% (P < 0.001) after EBRT. This modified stratification system was significantly more accurate than the three-tiered NCCN system currently in clinical use for all outcomes. Modifying the NCCN risk-stratification system to group FIR with low-risk patients and UIR with SHR patients, results in modestly improved prediction of outcomes, potentially allowing better personalisation of therapeutic recommendations. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

Effective Momentum and heat flux models for simulation of stratification and mixing in a large pool of water

Energy Technology Data Exchange (ETDEWEB)

Hua Li; Villanueva, W.; Kudinov, P. [Royal Institute of Technology (KTH). Div. of Nuclear Power Safety, Stockholm (Sweden)

2012-06-15

Performance of a boiling water reactor (BWR) containment is mostly determined by reliable operation of pressure suppression pool which serves as a heat sink to cool and condense steam released from the core vessel. Thermal stratification in the pool can significantly impede the pool's pressure suppression capacity. A source of momentum is required in order to break stratification and mix the pool. It is important to have reliable prediction of transient development of stratification and mixing in the pool in different regimes of steam injection. Previously, we have proposed to model the effect of steam injection on the mixing and stratification with the Effective Heat Source (EHS) and the Effective Momentum Source (EMS) models. The EHS model is used to provide thermal effect of steam injection on the pool, preserving heat and mass balance. The EMS model is used to simulate momentum induced by steam injection in different flow regimes. The EMS model is based on the combination of (1) synthetic jet theory, which predicts effective momentum if amplitude and frequency of flow oscillations in the pipe are given, and (2) model proposed by Aya and Nariai for prediction of the amplitude and frequency of oscillations at a given pool temperature and steam mass flux. The complete EHS/EMS models only require the steam mass flux, initial pool bulk temperature, and design-specific parameters, to predict thermal stratification and mixing in a pressure suppression pool. In this work we use EHS/EMS models implemented in containment thermal hydraulic code GOTHIC. The POOLEX/PPOOLEX experiments (Lappeenranta University of Technology, Finland) are utilized, to (a) quantify errors due to GOTHIC's physical models and numerical schemes, (b) propose necessary improvements in GOTHIC sub-grid scale modeling, and (c) validate our proposed models. Specifically the data from POOLEX STB-21 and PPOOLEX STR-03 and STR-04 tests are used for validation of the EHS and EMS models in this

Effective Momentum and heat flux models for simulation of stratification and mixing in a large pool of water

International Nuclear Information System (INIS)

Hua Li; Villanueva, W.; Kudinov, P.

2012-06-01

Performance of a boiling water reactor (BWR) containment is mostly determined by reliable operation of pressure suppression pool which serves as a heat sink to cool and condense steam released from the core vessel. Thermal stratification in the pool can significantly impede the pool's pressure suppression capacity. A source of momentum is required in order to break stratification and mix the pool. It is important to have reliable prediction of transient development of stratification and mixing in the pool in different regimes of steam injection. Previously, we have proposed to model the effect of steam injection on the mixing and stratification with the Effective Heat Source (EHS) and the Effective Momentum Source (EMS) models. The EHS model is used to provide thermal effect of steam injection on the pool, preserving heat and mass balance. The EMS model is used to simulate momentum induced by steam injection in different flow regimes. The EMS model is based on the combination of (1) synthetic jet theory, which predicts effective momentum if amplitude and frequency of flow oscillations in the pipe are given, and (2) model proposed by Aya and Nariai for prediction of the amplitude and frequency of oscillations at a given pool temperature and steam mass flux. The complete EHS/EMS models only require the steam mass flux, initial pool bulk temperature, and design-specific parameters, to predict thermal stratification and mixing in a pressure suppression pool. In this work we use EHS/EMS models implemented in containment thermal hydraulic code GOTHIC. The POOLEX/PPOOLEX experiments (Lappeenranta University of Technology, Finland) are utilized, to (a) quantify errors due to GOTHIC's physical models and numerical schemes, (b) propose necessary improvements in GOTHIC sub-grid scale modeling, and (c) validate our proposed models. Specifically the data from POOLEX STB-21 and PPOOLEX STR-03 and STR-04 tests are used for validation of the EHS and EMS models in this work. We

Modelling piezoelectric energy harvesting potential in an educational building

International Nuclear Information System (INIS)

Li, Xiaofeng; Strezov, Vladimir

2014-01-01

Highlights: • Energy harvesting potential of commercialized piezoelectric tiles is analyzed. • The parameters which will affect the energy harvesting efficiency are determined. • The potential could cover 0.5% of the total energy usage of the library building. • A simplified evaluation indicator is proposed to test the considered paving area. - Abstract: In this paper, potential application of a commercial piezoelectric energy harvester in a central hub building at Macquarie University in Sydney, Australia is examined and discussed. Optimization of the piezoelectric tile deployment is presented according to the frequency of pedestrian mobility and a model is developed where 3.1% of the total floor area with the highest pedestrian mobility is paved with piezoelectric tiles. The modelling results indicate that the total annual energy harvesting potential for the proposed optimized tile pavement model is estimated at 1.1 MW h/year. This potential energy generation may be further increased to 9.9 MW h/year with a possible improvement in piezoelectric energy conversion efficiency integrated into the system. This energy harvesting potential would be sufficient to meet close to 0.5% of the annual energy needs of the building. The study confirms that locating high traffic areas is critical for optimization of the energy harvesting efficiency, as well as the orientation of the tile pavement significantly affects the total amount of the harvested energy. A Density Flow evaluation is recommended in this study to qualitatively evaluate the piezoelectric power harvesting potential of the considered area based on the number of pedestrian crossings per unit time

The formation of low-angle eolian stratification through the migration of protodunes

Science.gov (United States)

Ewing, R. C.; Phillips, J. D.; Weymer, B. A.; Barrineaux, P.; Bowling, R.; Nittrouer, J. A.

2017-12-01

Protodunes are low-relief, slipfaceless migrating bed forms that represent the emergent form of eolian sand dunes. Protodunes develop as cm-scale topography out of a flat bed of sand and evolve spatially and temporally into dunes with angle-of-repose slipfaces. Protodunes at White Sands Dune Field in New Mexico form at the upwind, trailing margin of the field, on dune stoss slopes, and in interdune areas. Here we analyze protodunes at the upwind margin of White Sands by coupling 200 mHz ground penetrating radar (GPR) with time-series high-resolution topography to characterize the origin and evolution of protodune stratification and the stratigraphic transition into fully developed dunes. We surveyed a 780m transect in the resultant transport direction of the dune field from SW to NE from sand patches through protodunes and into the first dune. We used airborne lidar surveys and structure-from-motion photogrammetry from 2007, 2008, 2009, 2010, 2015, and 2016. We find that protodune stratification forms at angles between 0-10 degrees by protodune migration. Dip angles increase as protodune amplitude increases along the transect. Accumulation of low-angle stratification increases across the first 650m and ranges from none to subcritical. Nearly aggradational accumulation of low-angle stratification occurs over the last 100m and is a precursor to angle-of-repose slipface formation. The origins of the aggradation and slipface development appear to be linked to protodune merging, dune interactions, and possibly to the development of a dune field-scale boundary layer. Protodunes and the formation of low-angle stratification at the upwind margin of White Sands are a good analog to the initiation of dune field development from sand sheets and the formation of low-angle stratification found at the base of eolian successions in the stratigraphic record.

External validation of scoring systems in risk stratification of upper gastrointestinal bleeding.

Science.gov (United States)

Anchu, Anna Cherian; Mohsina, Subair; Sureshkumar, Sathasivam; Mahalakshmy, T; Kate, Vikram

2017-03-01

The aim of this study was to externally validate the four commonly used scoring systems in the risk stratification of patients with upper gastrointestinal bleed (UGIB). Patients of UGIB who underwent endoscopy within 24 h of presentation were stratified prospectively using the pre-endoscopy Rockall score (PRS) >0, complete Rockall score (CRS) >2, Glasgow Blatchford bleeding scores (GBS) >3, and modified GBS (m-GBS) >3 scores. Patients were followed up to 30 days. Prognostic accuracy of the scores was done by comparing areas under curve (AUC) in terms of overall risk stratification, re-bleeding, mortality, need for intervention, and length of hospitalization. One hundred and seventy-five patients were studied. All four scores performed better in the overall risk stratification on AUC [PRS = 0.566 (CI: 0.481-0.651; p-0.043)/CRS = 0.712 (CI: 0.634-0.790); p0.001); m-GBS = 0.802 (CI: 0.734-0.871; pbleed [AUC-0.679 (CI: 0.579-0.780; p = 0.003)]. All the scoring systems except PRS were found to be significantly better in detecting 30-day mortality with a high AUC (CRS = 0.798; p-0.042)/GBS = 0.833; p-0.023); m-GBS = 0.816; p-0.031). All four scores demonstrated significant accuracy in the risk stratification of non-variceal patients; however, only GBS and m-GBS were significant in variceal etiology. Higher cutoff scores achieved better sensitivity/specificity [RS > 0 (50/60.8), CRS > 1 (87.5/50.6), GBS > 7 (88.5/63.3), m-GBS > 7(82.3/72.6)] in the risk stratification. GBS and m-GBS appear to be more valid in risk stratification of UGIB patients in this region. Higher cutoff values achieved better predictive accuracy.

Impact of redox-stratification on the diversity and distribution of bacterial communities in sandy reef sediments in a microcosm

Institute of Scientific and Technical Information of China (English)

GAO Zheng; WANG Xin; Angelos K. HANNIDES; Francis J. SANSONE; WANG Guangyi

2011-01-01

Relationships between microbial communities and geochemical environments are important in marine microbial ecology and biogeochemistry.Although biogeochemical redox stratification has been well documented in marine sediments,its impact on microbial communities remains largely unknown.In this study,we applied denaturing gradient gel electrophoresis (DGGE) and clone library construction to investigate the diversity and stratification of bacterial communities in redox-stratified sandy reef sediments in a microcosm.A total of 88 Operational Taxonomic Units (OTU) were identified from 16S rRNA clone libraries constructed from sandy reef sediments in a laboratory microcosm.They were members of nine phyla and three candidate divisions,including Proteobacteria (Alpha-,Beta-,Gamma-,Delta-,and Epsilonproteobacteria),Actinobacteria,Acidobacteria,Bacteroidetes,Chloroflexi,Cyanobacteria,Firmicutes,Verrucomicrobia,Spirochaetes,and the candidate divisions WS3,SO31 and AO19.The vast majority of these phylotypes are related to clone sequences from other marine sediments,but OTUs of Epsilonproteobacteria and WS3 are reported for the first time from permeable marine sediments.Several other OTUs are potential new bacterial phylotypes because of their low similarity with reference sequences.Results from the 16S rRNA,gene clone sequence analyses suggested that bacterial communities exhibit clear stratification across large redox gradients in these sediments,with the highest diversity found in the anoxic layer (15-25 mm) and the least diversity in the suboxic layer (3-5 mm).Analysis of the nosZ,and amoA gene libraries also indicated the stratification of denitrifiers and nitrifiers,with their highest diversity being in the anoxic and oxic sediment layers,respectively.These results indicated that redox-stratification can affect the distribution of bacterial communities in sandy reef sediments.

Fatigue of LMFBR piping due to flow stratification

International Nuclear Information System (INIS)

Woodward, W.S.

1983-01-01

Flow stratification due to reverse flow was simulated in a 1/5-scale water model of a LMFBR primary pipe loop. The stratified flow was observed to have a dynamic interface region which oscillated in a wave pattern. The behavior of the interface was characterized in terms of location, local temperature fluctuation and duration for various reverse flow conditions. A structural assessment was performed to determine the effects of stratified flow on the fatigue life of the pipe. Both the static and dynamic aspects of flow stratification were examined. The dynamic interface produces thermal striping on the inside of the pipe wall which is shown to have the most deleterious effect on the pipe wall and produce significant fatigue damage relative to a static interface

Fatigue of LMFBR piping due to flow stratification

Energy Technology Data Exchange (ETDEWEB)

Woodward, W.S.

1983-01-01

Flow stratification due to reverse flow was simulated in a 1/5-scale water model of a LMFBR primary pipe loop. The stratified flow was observed to have a dynamic interface region which oscillated in a wave pattern. The behavior of the interface was characterized in terms of location, local temperature fluctuation and duration for various reverse flow conditions. A structural assessment was performed to determine the effects of stratified flow on the fatigue life of the pipe. Both the static and dynamic aspects of flow stratification were examined. The dynamic interface produces thermal striping on the inside of the pipe wall which is shown to have the most deleterious effect on the pipe wall and produce significant fatigue damage relative to a static interface.

Formulation parameters influencing self-stratification of coatings

NARCIS (Netherlands)

Vink, P.; Bots, T.L.

1996-01-01

Research was carried out aimed at the development of self-stratifying paints for steel which after application during film formation spontaneously form two well established layers of primer and top coat. The parameters affecting stratification were investigated for combinations of epoxy resins and

Bandwidth Study on Energy Use and Potential Energy Savings Opportunities in U.S. Petroleum Refining

Energy Technology Data Exchange (ETDEWEB)

Sabine Brueske, Caroline Kramer, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. petroleum refining. The study relies on multiple sources to estimate the energy used in nine individual process areas, representing 68% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

Investigating Summer Thermal Stratification in Lake Ontario

Science.gov (United States)

James, S. C.; Arifin, R. R.; Craig, P. M.; Hamlet, A. F.

2017-12-01

Seasonal temperature variations establish strong vertical density gradients (thermoclines) between the epilimnion and hypolimnion. Accurate simulation of vertical mixing and seasonal stratification of large lakes is a crucial element of the thermodynamic coupling between lakes and the atmosphere in integrated models. Time-varying thermal stratification patterns can be accurately simulated with the versatile Environmental Fluid Dynamics Code (EFDC). Lake Ontario bathymetry was interpolated onto a 2-km-resolution curvilinear grid with vertical layering using a new approach in EFDC+, the so-called "sigma-zed" coordinate system which allows the number of vertical layers to be varied based on water depth. Inflow from the Niagara River and outflow to the St. Lawrence River in conjunction with hourly meteorological data from seven local weather stations plus three-hourly data from the North American Regional Reanalysis govern the hydrodynamic and thermodynamic responses of the Lake. EFDC+'s evaporation algorithm was updated to more accurately simulate net surface heat fluxes. A new vertical mixing scheme from Vinçon-Leite that implements different eddy diffusivity formulations above and below the thermocline was compared to results from the original Mellor-Yamada vertical mixing scheme. The model was calibrated by adjusting solar-radiation absorption coefficients in addition to background horizontal and vertical mixing parameters. Model skill was evaluated by comparing measured and simulated vertical temperature profiles at shallow (20 m) and deep (180 m) locations on the Lake. These model improvements, especially the new sigma-zed vertical discretization, accurately capture thermal-stratification patterns with low root-mean-squared errors when using the Vinçon-Leite vertical mixing scheme.

Predicting Induced Radioactivity at High Energy Accelerators

Energy Technology Data Exchange (ETDEWEB)

Fasso, Alberto

1999-08-27

Radioactive nuclides are produced at high-energy electron accelerators by different kinds of particle interactions with accelerator components and shielding structures. Radioactivity can also be induced in air, cooling fluids, soil and groundwater. The physical reactions involved include spallations due to the hadronic component of electromagnetic showers, photonuclear reactions by intermediate energy photons and low-energy neutron capture. Although the amount of induced radioactivity is less important than that of proton accelerators by about two orders of magnitude, reliable methods to predict induced radioactivity distributions are essential in order to assess the environmental impact of a facility and to plan its decommissioning. Conventional techniques used so far are reviewed, and a new integrated approach is presented, based on an extension of methods used at proton accelerators and on the unique capability of the FLUKA Monte Carlo code to handle the whole joint electromagnetic and hadronic cascade, scoring residual nuclei produced by all relevant particles. The radiation aspects related to the operation of superconducting RF cavities are also addressed.

Energy saving potential of energy services - experimentation on the life cycle of energy conversion equipment

International Nuclear Information System (INIS)

Dupont, M.

2006-12-01

Energy efficiency services are growing in Europe but their role is still limited. In order to evaluate the potential, we focused first of all on policy, economical and environmental mechanisms that support their development. European natural gas and electricity markets, that are now almost wholly de-regulated, are analysed and compared to their historical structure. By introducing uncertainty on energy prices, this new deal translates better the real energy costs. Energy performance contracts (EPC) limit the impact of these uncertainties on the customer energy bills by guaranteeing a financial result. As a result of the modelling of these contracts, namely operation and maintenance ones, we prove that they transfer technical and financial risks from building owners to energy service companies (ESCO) making energy saving measures easier and less expensive at the same time. These contracts are relatively widespread for heating or compressed-air processes but remain marginal for air-conditioning systems. So new methods were needed to guarantee on the long terms the efficiency of air-conditioning systems demand (1) to master the process and its performances and (2) to be able to determine precisely the energy saving potential and its realisation costs. A detailed energy audit is thus necessary for which we propose a guidance. Conclusions of audits carried out prove that energy saving potential is mainly located in equipment management and control. These optimizations are not always carried out because of a lack of contractual incentive and due to the weaknesses of audit methods. Through the involvement of an independent expert, the mandatory and regular inspection of air-conditioning systems may allow to verify and guide such practices. A three-step analysis procedure has been developed in order to maximize the inspection potential and to get higher benefits from service contracts. (author)

Energy efficiency potential study for New Brunswick

International Nuclear Information System (INIS)

1992-05-01

The economic and environmental impacts associated with economically attractive energy savings identified in each of four sectors in New Brunswick are analyzed. The results are derived through a comparison of two potential future scenarios. The frozen efficiency scenario projects what future energy expenditures would be if no new energy efficiency initiatives are introduced. The economic potential scenario projects what those expenditures would be if all economically attractive energy efficiency improvements were gradually implemented over the next 20 years. Energy related emissions are estimated under scenarios with and without fuel switching. The results show, for example, that New Brunswick's energy related CO 2 emissions would be reduced by ca 5 million tonnes in the year 2000 under the economic potential scenario. If fuel switching is adopted, an additional 1 million tonnes of CO 2 emissions could be saved in the year 2000 and 1.6 million tonnes in 2010. The economic impact analysis is restricted to efficiency options only and does not consider fuel switching. Results show the effect of the economic potential scenario on employment, government revenues, and intra-industry distribution of employment gains and losses. The employment impact is estimated as the equivalent of the creation of 2,424 jobs annually over 1991-2010. Government revenues would increase by ca $24 million annually. The industries benefitting most from energy efficiency improvements would be those related to construction, retail trade, finance, real estate, and food/beverages. Industries adversely affected would be the electric power, oil, and coal sectors. 2 figs., 37 tabs

Preliminary results of total kinetic energy modelling for neutron-induced fission

International Nuclear Information System (INIS)

Visan, I.; Giubega, G.; Tudora, A.

2015-01-01

The total kinetic energy as a function of fission fragments mass TKE(A) is an important quantity entering in prompt emission calculations. The experimentally distributions of TKE(A) are referring to a limited number of fission systems and incident energies. In the present paper, a preliminary model for TKE calculation in neutron induced fission system is presented. The range of fission fragments is chosen as in the Point by Point treatment. The model needs as input only mass excesses and deformation parameters taken from available nuclear databases being based on the following approximations: total excitation energy of fully accelerated fission fragments TXE is calculated from energy balance of neutron-induced fission systems as sum of the total excitation energy at scission E*sciss and deformation energy Edef. The deformation energy at scission is given by minimizing the potential energy at the scission configuration. At the scission point, the fission system is described by two spheroidal fragments nearly touching by a pre-scission distance or neck caused by the nuclear forces between fragments. Therefore, the Columbian repulsion depending on neck and, consequently, on the fragments deformation at scission, is essentially in TKE determination. An approximation is made based on the fission modes. For the very symmetric fission, the dominant super long channel is characterized by long distance between fragments leading to low TKE values. Due to magic and double-magic shells closure, the dominant S1 fission mode for pairs with heavy fragment mass AH around 130-134 is characterized by spherical heavy fragment shape and easily deformed light fragment. The nearly spherical shape of the complementary fragments are characterized by minimum distance, and consequently to maximum TKE values. The results obtained for TKE(A) are in good agreement with existing experimental data for many neutron induced fission systems, e.g. ''2''3''3&apos

Coolant stratification and its thermohydrodynamic specificity under natural circulation in horizontal steam generator collectors

Energy Technology Data Exchange (ETDEWEB)

Blagovechtchenski, A.; Leontieva, V.; Mitriukhin, A. [Saint-Petersburg Technical Univ. (Russian Federation)

1997-12-31

The experiments and the test facilities for the study of the stratification phenomenon in the hot plenum of reactor and the upper parts of the steam generator collectors in a nuclear power plant are described. The aim of the experiments was to define the conditions of the stratification initiation, to study the temperature field in the upper part, the definition of the characteristics in the stratification layer, and also to study the factors which cause the intensity of the stagnant volume cooling.

Coolant stratification and its thermohydrodynamic specificity under natural circulation in horizontal steam generator collectors

Energy Technology Data Exchange (ETDEWEB)

Blagovechtchenski, A; Leontieva, V; Mitriukhin, A [Saint-Petersburg Technical Univ. (Russian Federation)

1998-12-31

The experiments and the test facilities for the study of the stratification phenomenon in the hot plenum of reactor and the upper parts of the steam generator collectors in a nuclear power plant are described. The aim of the experiments was to define the conditions of the stratification initiation, to study the temperature field in the upper part, the definition of the characteristics in the stratification layer, and also to study the factors which cause the intensity of the stagnant volume cooling.

Risk stratification in emergency patients by copeptin

DEFF Research Database (Denmark)

Iversen, Kasper; Gøtze, Jens P; Dalsgaard, Morten

2014-01-01

BACKGROUND: Rapid risk stratification is a core task in emergency medicine. Identifying patients at high and low risk shortly after admission could help clinical decision-making regarding treatment, level of observation, allocation of resources and post discharge follow-up. The purpose of the pre...

Quantitative risk stratification in Markov chains with limiting conditional distributions.

Science.gov (United States)

Chan, David C; Pollett, Philip K; Weinstein, Milton C

2009-01-01

Many clinical decisions require patient risk stratification. The authors introduce the concept of limiting conditional distributions, which describe the equilibrium proportion of surviving patients occupying each disease state in a Markov chain with death. Such distributions can quantitatively describe risk stratification. The authors first establish conditions for the existence of a positive limiting conditional distribution in a general Markov chain and describe a framework for risk stratification using the limiting conditional distribution. They then apply their framework to a clinical example of a treatment indicated for high-risk patients, first to infer the risk of patients selected for treatment in clinical trials and then to predict the outcomes of expanding treatment to other populations of risk. For the general chain, a positive limiting conditional distribution exists only if patients in the earliest state have the lowest combined risk of progression or death. The authors show that in their general framework, outcomes and population risk are interchangeable. For the clinical example, they estimate that previous clinical trials have selected the upper quintile of patient risk for this treatment, but they also show that expanded treatment would weakly dominate this degree of targeted treatment, and universal treatment may be cost-effective. Limiting conditional distributions exist in most Markov models of progressive diseases and are well suited to represent risk stratification quantitatively. This framework can characterize patient risk in clinical trials and predict outcomes for other populations of risk.

Randomization in clinical trials: stratification or minimization? The HERMES free simulation software.

Science.gov (United States)

Fron Chabouis, Hélène; Chabouis, Francis; Gillaizeau, Florence; Durieux, Pierre; Chatellier, Gilles; Ruse, N Dorin; Attal, Jean-Pierre

2014-01-01

Operative clinical trials are often small and open-label. Randomization is therefore very important. Stratification and minimization are two randomization options in such trials. The first aim of this study was to compare stratification and minimization in terms of predictability and balance in order to help investigators choose the most appropriate allocation method. Our second aim was to evaluate the influence of various parameters on the performance of these techniques. The created software generated patients according to chosen trial parameters (e.g., number of important prognostic factors, number of operators or centers, etc.) and computed predictability and balance indicators for several stratification and minimization methods over a given number of simulations. Block size and proportion of random allocations could be chosen. A reference trial was chosen (50 patients, 1 prognostic factor, and 2 operators) and eight other trials derived from this reference trial were modeled. Predictability and balance indicators were calculated from 10,000 simulations per trial. Minimization performed better with complex trials (e.g., smaller sample size, increasing number of prognostic factors, and operators); stratification imbalance increased when the number of strata increased. An inverse correlation between imbalance and predictability was observed. A compromise between predictability and imbalance still has to be found by the investigator but our software (HERMES) gives concrete reasons for choosing between stratification and minimization; it can be downloaded free of charge. This software will help investigators choose the appropriate randomization method in future two-arm trials.

Review of Turkey's renewable energy potential

International Nuclear Information System (INIS)

Ozgur, M. Arif

2008-01-01

The use of renewable energy has a long history. Biomass, for instance, has been used for heating and cooking, while wind has been used in the irrigation of fields and to drive windmills for centuries. Although Turkey has many energy resources, all of these with the exception of coal and hydropower, cannot meet the total energy demand. Turkey has been importing resources to meet this deficit. These resources have become increasingly expensive and also have undesirably high emissions ratings. Turkey has an extensive shoreline and mountains and is rich in renewable energy potential. The share of renewables on total electricity generation is 29.63% while that of natural gas is 45% for the year 2006. The projection prepared for the period between 2006 and 2020 aims an annual growth of 8% for the total electricity generation. According to this projection, it is expected that renewables will have a share about 23.68% with a decrease of 5.95% while natural gas will have a share about 33.38% for 2020. This paper presents the present state of world renewable energy sources and then looks in detail at the potential resources available in Turkey. Energy politics are also considered. (author)

Wind energy potential analysis in Al-Fattaih-Darnah

Energy Technology Data Exchange (ETDEWEB)

Tjahjana, Dominicus Danardono Dwi Prija, E-mail: danar1405@gmail.com; Salem, Abdelkarim Ali, E-mail: keemsalem@gmail.com; Himawanto, Dwi Aries, E-mail: dwiarieshimawanto@gmail.com [University of Sebelas Maret, Jl. Ir. Sutami No. 36 A, Surakarta, Indonesia 57126 (Indonesia)

2016-03-29

In this paper the wind energy potential in Al-Fattaih-Darnah, Libya, had been studied. Wind energy is very attractive because it can provide a clean and renewable energy. Due mostly to the uncertainty caused by the chaotic characteristics of wind near the earth’s surface, wind energy characteristic need to be investigated carefully in order to get consistent power generation. This investigation was based on one year wind data measured in 2003. As a result of the analysis, wind speed profile and wind energy potential have been developed. The wind energy potential of the location is looked very promising to generate electricity. The annual wind speed of the site is 8.21 m/s and the wind speed carrying maximum energy is 7.97 m/s. The annual power density of the site is classified into class 3. The Polaris P50-500 wind turbine can produce 768.39 M Wh/year and has capacity factor of 17.54%.

Free-energy coarse-grained potential for C60

International Nuclear Information System (INIS)

Edmunds, D. M.; Tangney, P.; Vvedensky, D. D.; Foulkes, W. M. C.

2015-01-01

We propose a new deformable free energy method for generating a free-energy coarse-graining potential for C 60 . Potentials generated from this approach exhibit a strong temperature dependence and produce excellent agreement with benchmark fully atomistic molecular dynamics simulations. Parameter sets for analytical fits to this potential are provided at four different temperatures

Renewable energy potential from biomass residues in Egypt

Energy Technology Data Exchange (ETDEWEB)

Said, N.; Zamorano, M. [Civil Engineering Dept., Univ. of Granada, Campus de Fuentenueva, Granada (Spain); El-Shatoury, S.A. [Botany Dept., Faculty of Sciences, Suez Canal Univ., Ismailia (Egypt)

2012-11-01

Egypt has been one of the developing countries following successful programs for the development of renewable energy resources, with special emphasis on solar, wind and biomass. Utilization of biomass as a source of energy is important from energetic as well as environmental viewpoint. Furthermore, Egypt produces millions of biomass waste every year causing pollution and health problems. So, the incorporation of biomass with other renewable energy will increase the impact of solving energy and environmental problem. There is a good potential for the utilization of biomass energy resources in Egypt. Four main types of biomass energy sources are included in this study: agricultural residues, municipal solid wastes, animal wastes and sewage sludge. Analysis of the potential biomass resource quantity and its theoretical energy content has been computed according to literature review. The agriculture crop residue represents the main source of biomass waste with a high considerable amount of the theoretical potential energy in Egypt. Rice straw is considered one of the most important of such residue due to its high amount and its produced energy through different conversion techniques represent a suitable candidate for crop energy production in Egypt.

Dependence of offshore wind turbine fatigue loads on atmospheric stratification

DEFF Research Database (Denmark)

Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Ott, Søren

2014-01-01

The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representi...... conditions. In general, impact of ABL stratification is clearly seen on wake affected inflow cases for both blade and tower fatigue loads. However, the character of this dependence varies significantly with the type of inflow conditions – e.g. single wake inflow or multiple wake inflow....

Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Chemical Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Sabine Brueske, Caroline Kramer, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. chemical manufacturing. The study relies on multiple sources to estimate the energy used in the production of 74 individual chemicals, representing 57% of sector-wide energy consumption. Energy savings opportunities for individual chemicals and for 15 subsectors of chemicals manufacturing are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

Response of water temperatures and stratification to changing climate in three lakes with different morphometry

Science.gov (United States)

Magee, Madeline R.; Wu, Chin H.

2017-12-01

Water temperatures and stratification are important drivers for ecological and water quality processes within lake systems, and changes in these with increases in air temperature and changes to wind speeds may have significant ecological consequences. To properly manage these systems under changing climate, it is important to understand the effects of increasing air temperatures and wind speed changes in lakes of different depths and surface areas. In this study, we simulate three lakes that vary in depth and surface area to elucidate the effects of the observed increasing air temperatures and decreasing wind speeds on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes) over a century (1911-2014). For all three lakes, simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, stability increased, and longwave and sensible heat fluxes at the surface increased. Overall, lake depth influences the presence of stratification, Schmidt stability, and differences in surface heat flux, while lake surface area influences differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates. Larger surface area lakes have greater wind mixing due to increased surface momentum. Climate perturbations indicate that our larger study lakes have more variability in temperature and stratification variables than the smaller lakes, and this variability increases with larger wind speeds. For all study lakes, Pearson correlations and climate perturbation scenarios indicate that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature, and wind can act to either amplify or mitigate the effect of warmer air temperatures on lake thermal

Calculation of molecular free energies in classical potentials

International Nuclear Information System (INIS)

Farhi, Asaf; Singh, Bipin

2016-01-01

Free energies of molecules can be calculated by quantum chemistry computations or by normal mode classical calculations. However, the first can be computationally impractical for large molecules and the second is based on the assumption of harmonic dynamics. We present a novel, accurate and complete calculation of molecular free energies in standard classical potentials. In this method we transform the molecule by relaxing potential terms which depend on the coordinates of a group of atoms in that molecule and calculate the free energy difference associated with the transformation. Then, since the transformed molecule can be treated as non-interacting systems, the free energy associated with these atoms is analytically or numerically calculated. This two-step calculation can be applied to calculate free energies of molecules or free energy difference between (possibly large) molecules in a general environment. We demonstrate the method in free energy calculations for methanethiol and butane molecules in vacuum and solvent. We suggest the potential application of free energy calculation of chemical reactions in classical molecular simulations. (paper)

Monitoring of coolant temperature stratification on piping components in WWER-440 NPPs

International Nuclear Information System (INIS)

Hudcovsky, S.; Slanina, M.; Badiar, S.

2001-01-01

The presentation deals with the aims of non-standard temperature measurements installed on primary and secondary circuit in WWER-440 NPPs, explains reasons of coolant temperature stratification on the piping components. It describes methods of the measurements on pipings, range of installation of the temperature measurements in EBO and EMO units and illustrates results of measurements of coolant temperature stratification. (Authors)

Woody biomass energy potential in 2050

International Nuclear Information System (INIS)

Lauri, Pekka; Havlík, Petr; Kindermann, Georg; Forsell, Nicklas; Böttcher, Hannes; Obersteiner, Michael

2014-01-01

From a biophysical perspective, woody biomass resources are large enough to cover a substantial share of the world's primary energy consumption in 2050. However, these resources have alternative uses and their accessibility is limited, which tends to decrease their competitiveness with respect to other forms of energy. Hence, the key question of woody biomass use for energy is not the amount of resources, but rather their price. In this study we consider the question from the perspective of energy wood supply curves, which display the available amount of woody biomass for large-scale energy production at various hypothetical energy wood prices. These curves are estimated by the Global Biosphere Management Model (GLOBIOM), which is a global partial equilibrium model of forest and agricultural sectors. The global energy wood supply is estimated to be 0–23 Gm 3 /year (0–165 EJ/year) when energy wood prices vary in a range of 0–30$/GJ (0–216$/m 3 ). If we add household fuelwood to energy wood, then woody biomass could satisfy 2–18% of world primary energy consumption in 2050. If primary forests are excluded from wood supply then the potential decreases up to 25%. - highlights: • We examine woody biomass energy potential by partial equilibrium model of forest and agriculture sectors. • It is possible to satisfy 18% (or 14% if primary forests are excluded) of the world's primary energy consumption in 2050 by woody biomass. • To achieve this would require an extensive subsidy/tax policy and would lead to substantial higher woody biomass prices compared to their current level

Energy changes in massive target-nuclei, induced by high-energy hadronic projectiles

International Nuclear Information System (INIS)

Strugalski, Z.; Strugalska-Gola, E.

1997-01-01

Now it turned out that it is real to estimate by experiments the energy changes in massive target-nuclei, induced by high-energy hadronic projectiles. The subject matter in this work is to present results of the quantitative estimations of the energy changes in intranuclear matter at various stages of hadron-nucleus collision reactions. Appropriate formulas are proposed for the energy balances - as following from the experimentally based mechanism of the hadron-nucleus collision reactions

Drought tolerance associated with vertical stratification of two co-occurring epiphytic bromeliads in a tropical dry forest.

Science.gov (United States)

Graham, Eric A; Andrade, Jose Luis

2004-05-01

Vertical stratification of epiphytes generally has not been reported for dry forests. For two epiphytic Crassulacean acid metabolism bromeliads that segregate vertically, it was hypothesized that different potentials for photoprotection or shade tolerance rather than drought tolerance is responsible for the observed stratification. The light environment, capacity for photoprotection, germination response to light quality, and responses to light and drought were thus examined for Tillandsia brachycaulos and T. elongata. Vertical and light-environment distributions differed for the two species but photoprotection and photodamage did not where they occurred at similar field locations; T. brachycaulos had a higher pigment acclimation to light. Tillandsia brachycaulos had higher acid accumulation under low light as opposed to T. elongata, which responded similarly to all but the highest light treatment. Tillandsia brachycaulos maintained positive total daily net CO(2) uptake through 30 d of drought; T. elongata had a total daily net CO(2) loss after 7 d of drought. The vertical stratification was most likely the result of the sensitivity to drought of T. elongata rather than differences in photoprotection or shade tolerance between the two species. Tillandsia elongata occurs in more exposed locations, which may be advantageous for rainfall interception and dew formation.

Seasonal variations of the upper ocean salinity stratification in the Tropics

Science.gov (United States)

Maes, Christophe; O'Kane, Terence J.

2014-03-01

In comparison to the deep ocean, the upper mixed layer is a region typically characterized by substantial vertical gradients in water properties. Within the Tropics, the rich variability in the vertical shapes and forms that these structures can assume through variation in the atmospheric forcing results in a differential effect in terms of the temperature and salinity stratification. Rather than focusing on the strong halocline above the thermocline, commonly referred to as the salinity barrier layer, the present study takes into account the respective thermal and saline dependencies in the Brunt-Väisälä frequency (N2) in order to isolate the specific role of the salinity stratification in the layers above the main pycnocline. We examine daily vertical profiles of temperature and salinity from an ocean reanalysis over the period 2001-2007. We find significant seasonal variations in the Brunt-Väisälä frequency profiles are limited to the upper 300 m depth. Based on this, we determine the ocean salinity stratification (OSS) to be defined as the stabilizing effect (positive values) due to the haline part of N2 averaged over the upper 300 m. In many regions of the tropics, the OSS contributes 40-50% to N2 as compared to the thermal stratification and, in some specific regions, exceeds it for a few months of the seasonal cycle. Away from the tropics, for example, near the centers of action of the subtropical gyres, there are regions characterized by the permanent absence of OSS. In other regions previously characterized with salinity barrier layers, the OSS obviously shares some common variations; however, we show that where temperature and salinity are mixed over the same depth, the salinity stratification can be significant. In addition, relationships between the OSS and the sea surface salinity are shown to be well defined and quasilinear in the tropics, providing some indication that in the future, analyses that consider both satellite surface salinity

Computed Potential Energy Surfaces and Minimum Energy Pathways for Chemical Reactions

Science.gov (United States)

Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

1994-01-01

Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. For some dynamics methods, global potential energy surfaces are required. In this case, it is necessary to obtain the energy at a complete sampling of all the possible arrangements of the nuclei, which are energetically accessible, and then a fitting function must be obtained to interpolate between the computed points. In other cases, characterization of the stationary points and the reaction pathway connecting them is sufficient. These properties may be readily obtained using analytical derivative methods. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives usefull results for a number of chemically important systems. The talk will focus on a number of applications including global potential energy surfaces, H + O2, H + N2, O(3p) + H2, and reaction pathways for complex reactions, including reactions leading to NO and soot formation in hydrocarbon combustion.

Unused energy sources inducing minimal pollution

Energy Technology Data Exchange (ETDEWEB)

Voss, A [Inst. fur Reaktorentwicklung, Kernforschungsanlage Julich GmbH, German Federal Republic

1974-01-01

The contribution of hydroelectricity to the growing worldwide energy demand is not expected to exceed 6%. As the largest amount of hydroelectric potential is located in developing nations, it will find its greatest development outside the currently industrialized sphere. The potential of 60 GW ascribed to tidal and geothermal energy is a negligible quantity. Solar energy represents an essentially inexhaustible source, but technological problems will preclude any major contribution from it during this century. The environmental problems caused by these 'new' energy sources are different from those engendered by fossil and nuclear power plants, but they are not negligible. It is irresponsible and misleading to describe them as pollution-free.

Dependence of offshore wind turbine fatigue loads on atmospheric stratification

International Nuclear Information System (INIS)

Hansen, K S; Larsen, G C; Ott, S

2014-01-01

The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representing blade-bending and tower bottom bending, are combined with the operational statistics from the instrumented wind turbine as well as with meteorological statistics defining the inflow conditions. Only a part of all possible inflow conditions are covered through the approximately 8200 hours of combined measurements. The fatigue polar has been determined for an (almost) complete 360° inflow sector for both load sensors, representing mean wind speeds below and above rated wind speed, respectively, with the inflow conditions classified into three different stratification regimes: unstable, neutral and stable conditions. In general, impact of ABL stratification is clearly seen on wake affected inflow cases for both blade and tower fatigue loads. However, the character of this dependence varies significantly with the type of inflow conditions – e.g. single wake inflow or multiple wake inflow

Simulation benchmark based on THAI-experiment on dissolution of a steam stratification by natural convection

Energy Technology Data Exchange (ETDEWEB)

Freitag, M., E-mail: freitag@becker-technologies.com; Schmidt, E.; Gupta, S.; Poss, G.

2016-04-01

Highlights: . • We studied the generation and dissolution of steam stratification in natural convection. • We performed a computer code benchmark including blind and open phases. • The dissolution of stratification predicted only qualitatively by LP and CFD models during the blind simulation phase. - Abstract: Locally enriched hydrogen as in stratification may contribute to early containment failure in the course of severe nuclear reactor accidents. During accident sequences steam might accumulate as well to stratifications which can directly influence the distribution and ignitability of hydrogen mixtures in containments. An international code benchmark including Computational Fluid Dynamics (CFD) and Lumped Parameter (LP) codes was conducted in the frame of the German THAI program. Basis for the benchmark was experiment TH24.3 which investigates the dissolution of a steam layer subject to natural convection in the steam-air atmosphere of the THAI vessel. The test provides validation data for the development of CFD and LP models to simulate the atmosphere in the containment of a nuclear reactor installation. In test TH24.3 saturated steam is injected into the upper third of the vessel forming a stratification layer which is then mixed by a superposed thermal convection. In this paper the simulation benchmark will be evaluated in addition to the general discussion about the experimental transient of test TH24.3. Concerning the steam stratification build-up and dilution of the stratification, the numerical programs showed very different results during the blind evaluation phase, but improved noticeable during open simulation phase.

Assessing the Potential for Renewable Energy on Public Lands

Energy Technology Data Exchange (ETDEWEB)

2003-02-01

This report represents an initial activity of the Bureau of Land Managements (BLM) proposed National Energy Policy Implementation Plan: identify and evaluate renewable energy resources on federal lands and any limitations on accessing them. Ultimately, BLM will prioritize land-use planning activities to increase industrys development of renewable energy resources. These resources include solar, biomass, geothermal, water, and wind energy. To accomplish this, BLM and the Department of Energys National Renewable Energy Laboratory (NREL) established a partnership to conduct an assessment of renewable energy resources on BLM lands in the western United States. The objective of this collaboration was to identify BLM planning units in the western states with the highest potential for private-sector development of renewable resources. The assessment resulted in the following findings: (1) 63 BLM planning units in nine western states have high potential for one or more renewable energy technologies; and (2) 20 BLM planning units in seven western states have high potential for power production from three or more renewable energy sources. This assessment report provides BLM with information needed to prioritize land-use planning activities on the basis of potential for the development of energy from renewable resources.

Variability of stratification according to operation of the tidal power plant in Lake Sihwa, South Korea.

Science.gov (United States)

Woo, S. B.; Song, J. I.; Jang, T. H.; Park, C. J.; Kwon, H. K.

2017-12-01

Artificial forcing according to operation of the tidal power plant (TPP) affects the physical environmental changes near the power plant. Strong turbulence by generation is expected to change the stratification structure of the Lake Sihwa inside. In order to examine the stratification changes by the power plant operation, ship bottom mounted observation were performed for 13 hours using an acoustic Doppler current profiler (ADCP) and Conductivity-Temperature-Depth (CTD) in Lake Sihwa at near TPP. The strong stratification in Sihwa Lake is maintained before TPP operation. The absence of external forces and freshwater inflow from the land forms the stratification in the Lake. Strong winds in a stratification statement lead to two-layer circulation. After wind event, multi-layer velocity structure is formed which lasted for approximately 4 h. After TPP operation, the jet flow was observed in entire water column at the beginning of the power generation. Vortex is formed by strong jet flow and maintained throughout during power generation period. Strong turbulence flow is generated by the turbine blades, enhancing vertical mixing. External forces, which dominantly affect Lake Sihwa, have changed from the wind to the turbulent flow. The stratification was extinguished by strong turbulent flow and becomes fully-mixed state. Changes in stratification structure are expected to affect material transport and ecological environment change continuously.

Energy potential of the modified excess sludge

Science.gov (United States)

Zawieja, Iwona

2017-11-01

On the basis of the SCOD value of excess sludge it is possible to estimate an amount of energy potentially obtained during the methane fermentation process. Based on a literature review, it has been estimated that from 1 kg of SCOD it is possible to obtain 3.48 kWh of energy. Taking into account the above methane and energy ratio (i.e. 10 kWh/1Nm3 CH4), it is possible to determine the volume of methane obtained from the tested sludge. Determination of potential energy of sludge is necessary for the use of biogas as a source of power generators as cogeneration and ensure the stability of this type of system. Therefore, the aim of the study was to determine the energy potential of excess sludge subjected to the thermal and chemical disintegration. In the case of thermal disintegration, test was conducted in the low temperature 80°C. The reagent used for the chemical modification was a peracetic acid, which in an aqueous medium having strong oxidizing properties. The time of chemical modification was 6 hours. Applied dose of the reagent was 1.0 ml CH3COOOH/L of sludge. By subjecting the sludge disintegration by the test methods achieved an increase in the SCOD value of modified sludge, indicating the improvement of biodegradability along with a concomitant increase in their energy potential. The obtained experimental production of biogas from disintegrated sludge confirmed that it is possible to estimate potential intensity of its production. The SCOD value of 2576 mg O2/L, in the case of chemical disintegration, was obtained for a dose of 1.0 ml CH3COOH/L. For this dose the pH value was equal 6.85. In the case of thermal disintegration maximum SCOD value was 2246 mg O2/L obtained at 80°C and the time of preparation 6 h. It was estimated that in case of thermal disintegration as well as for the chemical disintegration for selected parameters, the potential energy for model digester of active volume of 5L was, respectively, 0.193 and 0,118 kWh.

Energy potential of the modified excess sludge

Directory of Open Access Journals (Sweden)

Zawieja Iwona

2017-01-01

Full Text Available On the basis of the SCOD value of excess sludge it is possible to estimate an amount of energy potentially obtained during the methane fermentation process. Based on a literature review, it has been estimated that from 1 kg of SCOD it is possible to obtain 3.48 kWh of energy. Taking into account the above methane and energy ratio (i.e. 10 kWh/1Nm3 CH4, it is possible to determine the volume of methane obtained from the tested sludge. Determination of potential energy of sludge is necessary for the use of biogas as a source of power generators as cogeneration and ensure the stability of this type of system. Therefore, the aim of the study was to determine the energy potential of excess sludge subjected to the thermal and chemical disintegration. In the case of thermal disintegration, test was conducted in the low temperature 80°C. The reagent used for the chemical modification was a peracetic acid, which in an aqueous medium having strong oxidizing properties. The time of chemical modification was 6 hours. Applied dose of the reagent was 1.0 ml CH3COOOH/L of sludge. By subjecting the sludge disintegration by the test methods achieved an increase in the SCOD value of modified sludge, indicating the improvement of biodegradability along with a concomitant increase in their energy potential. The obtained experimental production of biogas from disintegrated sludge confirmed that it is possible to estimate potential intensity of its production. The SCOD value of 2576 mg O2/L, in the case of chemical disintegration, was obtained for a dose of 1.0 ml CH3COOH/L. For this dose the pH value was equal 6.85. In the case of thermal disintegration maximum SCOD value was 2246 mg O2/L obtained at 80°C and the time of preparation 6 h. It was estimated that in case of thermal disintegration as well as for the chemical disintegration for selected parameters, the potential energy for model digester of active volume of 5L was, respectively, 0.193 and 0,118 kWh.

Geothermal Energy Potential in Western United States

Science.gov (United States)

Pryde, Philip R.

1977-01-01

Reviews types of geothermal energy sources in the western states, including hot brine systems and dry steam systems. Conversion to electrical energy is a major potential use of geothermal energy, although it creates environmental disruptions such as noise, corrosion, and scaling of equipment. (AV)

A novel kerf-free wafering process combining stress-induced spalling and low energy hydrogen implantation

Energy Technology Data Exchange (ETDEWEB)

Pingault, Timothee; Pokam-Kuisseu, Pauline Sylvia; Ntsoenzok, Esidor [CEMTHI - CNRS, Site Cyclotron, 3 A rue de la Ferollerie, 45071 Orleans (France); Blondeau, Jean-Philippe [CEMTHI - CNRS, Site Cyclotron, 3 A rue de la Ferollerie, 45071 Orleans (France); Universite d' Orleans, Chateau de la Source, 45100 Orleans (France); Ulyashin, Alexander [SINTEF, Forskningsveien 1, 0314 Oslo (Norway); Labrim, Hicham; Belhorma, Bouchra [CNESTEN, B.P. 1382 R.P., 10001 Rabat (Morocco)

2016-12-15

In this work, we studied the potential use of low-energy hydrogen implantation as a guide for the stress-induced cleavage. Low-energy, high fluence hydrogen implantation in silicon leads, in the right stiffening conditions, to the detachment of a thin layer, around a few hundreds nm thick, of monocrystalline silicon. We implanted monocrystalline silicon wafers with low-energy hydrogen, and then glued them on a cheap metal layer. Upon cooling down, the stress induced by the stressor layers (hardened glue and metal) leads to the detachment of a thin silicon layer, which thickness is determined by the implantation energy. We were then able to clearly demonstrate that, as expected, hydrogen oversaturation layer is very efficient to guide the stress. Using such process, thin silicon layers of around 710 nm-thick were successfully detached from low-energy implanted silicon wafers. Such layers can be used for the growth of very good quality monocrystalline silicon of around 50 μm-thick or less. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Defining The Energy Saving Potential of Architectural Design

DEFF Research Database (Denmark)

Naboni, Emanuele; Malcangi, Antonio; Zhang, Yi

2015-01-01

Designers, in response to codes or voluntary " green building " programs, are increasingly concerned with building energy demand reduction, but they are not fully aware of the energy saving potential of architectural design. According to literature, building form, construction and material choices...... on sustainable design: " Design With Climate " by Olgyay (1963), which discussed strategies for climate-adapted architecture, and Lechner´s " Heating, Cooling and Lighting " (1991), on how to reduce building energy needs by as much as 60 – 80 percent with proper architectural design decisions. Both books used...... behaviour. The research shows the best solution for each of the climates and compares them with Olgyay´s findings. Finally, for each climate the energy saving potential is defined and then compared to Lechner's conclusions. Defining The Energy Saving Potential of Architectural Design (PDF Download Available...

The wind energy potential in Argentina

International Nuclear Information System (INIS)

Alvarez, P

2005-01-01

The wind energy are increasing its contribution to large scale electricity generation in many countries.The high technical maturity reached by modern wind turbines returns it viable and competitive in many regions, specially in those where a suitable legal framework stimulates the generation from renewable sources of energy.As this regard, the objective of this report is to demonstrate that, far from being limited to provide energy to remote, dispersed or geographically isolated sites not served by conventional networks, the wind energy has fully potential to supply a pretty relevant part of the electrical consumption of the great urban centers located in those zones of the country favored with this resource.For it, two preliminary estimations has done: the total 'windy' surface area in geographic proximity of the high voltage lines and electrical substations of the Argentine System of Interconnection (SADI) able 'to be seeded' with wind turbines, and the total electrical energy feasible of being generated from them.The paper supposes the exclusion of important non apt areas by virtue of strictly geographic, economic or environmental considerations.Even so, the result of the final calculation is extraordinarily high and promissory: if only 4% of the total surface of the contiguous land areas (in a maximum radius of 62 km) to the high voltage transmission system (in which the annual mean wind speed surpasses the 5.55 m/s) would be filled with power wind turbines, the annual average energy produced by them would be equivalent to 89% of the estimated national electrical consumption for year 2013.The usable wind potential in favorable technical conditions for commercial generation rounds this way around 40,000 MW, that would report an annual average energy of 100,000 GWh, occupying an area near 5000 km 2 .The total wind energy potential is (of course) considerably greater. Anyway, given the random nature of the wind and the consequent characteristics of not firm power

Career on the Move: Geography, Stratification, and Scientific Impact

Science.gov (United States)

Deville, Pierre; Wang, Dashun; Sinatra, Roberta; Song, Chaoming; Blondel, Vincent D.; Barabási, Albert-László

2014-04-01

Changing institutions is an integral part of an academic life. Yet little is known about the mobility patterns of scientists at an institutional level and how these career choices affect scientific outcomes. Here, we examine over 420,000 papers, to track the affiliation information of individual scientists, allowing us to reconstruct their career trajectories over decades. We find that career movements are not only temporally and spatially localized, but also characterized by a high degree of stratification in institutional ranking. When cross-group movement occurs, we find that while going from elite to lower-rank institutions on average associates with modest decrease in scientific performance, transitioning into elite institutions does not result in subsequent performance gain. These results offer empirical evidence on institutional level career choices and movements and have potential implications for science policy.

Observed variations in stratification and currents in the Zuari estuary, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Sundar, D.; Unnikrishnan, A.S.; Michael, G.S.; Kankonkar, A.; Nidheesh, A.G.; Subeesh, M.P.

in stratification at different time scales (daily, spring–neap cycle and seasonal) are described. In the mixed tidal regime with semi-diurnal dominance, stratification at higher low water succeeding lower high water is more intense than that at lower low water...

Macro-Micro Linkages and the Role of Mechanisms in Social Stratification Research

Czech Academy of Sciences Publication Activity Database

Veselý, Arnošt; Smith, Michael

2008-01-01

Roč. 44, č. 3 (2008), s. 491-509 ISSN 0038-0288 R&D Projects: GA ČR GA403/08/0109; GA MPS(CZ) 1J/005/04-DP2 Institutional research plan: CEZ:AV0Z70280505 Keywords : Social stratification research * stratification processes * social mechanisms Subject RIV: AO - Sociology, Demography Impact factor: 0.427, year: 2008 http://dlib.lib.cas.cz/3508/

Economic Energy Savings Potential in Federal Buildings

Energy Technology Data Exchange (ETDEWEB)

Brown, Daryl R.; Dirks, James A.; Hunt, Diane M.

2000-09-04

The primary objective of this study was to estimate the current life-cycle cost-effective (i.e., economic) energy savings potential in Federal buildings and the corresponding capital investment required to achieve these savings, with Federal financing. Estimates were developed for major categories of energy efficiency measures such as building envelope, heating system, cooling system, and lighting. The analysis was based on conditions (building stock and characteristics, retrofit technologies, interest rates, energy prices, etc.) existing in the late 1990s. The potential impact of changes to any of these factors in the future was not considered.

Stratification of zooplankton in the northwestern Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Paulinose, V.T.; Gopalakrishnan, T.C.; Nair, K.K.C.; Aravindakshan, P.N.

Study on stratification of zooplankton in the north western Indian Ocean was carried out with special reference to its relative abundance and distribution. Samples were collected using multiple plankton net, during first cruise of ORV Sagar Kanya...

Microscopic optical potential at medium energies

International Nuclear Information System (INIS)

Malecki, A.

1979-01-01

The problems concerning a microscopic optical model for the elastic nuclear collisions at medium energies are discussed. We describe the method for constructing the optical potential which makes use of the particular properties of quantum scattering in the eikonal limit. The resulting potential is expressed in terms of the nuclear wave functions and the nucleon-nucleon scattering amplitudes. This potential has a dynamic character since by including the effects of multiple scattering it allows for the possibility of intermediate excitations of the projectile and target nuclei. The use of the potential in the exact wave equation accounts for the most important mechanisms present in the collisions between composite particles. The microscopic optical model was successfully applied in the analysis of elastic scattering of protons and α-particles on atomic nuclei in the energy range of 300-1000 MeV/nucleon. The dynamic optical potential in this case represents a considerable improvement over the eikonal Glauber model and the static optical potential of Watson. The possibilities to extend the microscopic description of the proton-nucleus interaction by considering the spin dependence of the elementary amplitude and the Majorana exchange effects were investigated. (author)

Valorization of potentials of wind energy in Montenegro

Directory of Open Access Journals (Sweden)

Vujadinović Radoje V.

2017-01-01

Full Text Available Investments in energy sector are usually long term processes both in construction and exploitation phase, and therefore require many conditions to be satisfied, mostly from legislative and technical sector. While the legislative can change in accordance with economy activities in the country, technical data (on-site measurements which are the main base for energy facility design, need to be reliable as much as possible. Wind energy has a significant global potential which exceeds the world’s electrical energy consumptions. This paper presents the estimation of wind energy potentials in Montenegro, based on all previous available studies in this field. The wind energy potential in Montenegro is based on a combination of 3-D numerical simulations of wind fields on the entire territory, and comprehensive on-site measurements. The preliminary studies show that there is a potential of areas with high and mean values of a capacity factor about 400 MW, and annual production of 900 GWh of electric energy. The share of wind parks in the total installed power in Montenegro is planned to be about 8%, while an adequate ratio of wind parks in an annual production from renewable sources (large hydro power plants are included here is estimated to be 11.4%. The paper presents the current state of art in the field of building of wind parks in Montenegro. A particular attention was paid to the legislation framework and strategic documents in the energy area in Montenegro.

Appropriate bare potentials for studying fusion induced by 6He

International Nuclear Information System (INIS)

Crema, E; Chamon, L.C; Gomes, P.R.S.

2007-01-01

Although there are some recent studies questioning the use of the same optical potential to explain simultaneously fusion and quasi-elastic experimental data [1] or even to explain deep sub-barrier- and above-barrier fusion [2], during the last decades, the bare nuclear interaction between the nuclei at near barrier energies has been widely represented by a frozen potential with a Woods-Saxon shape. Another well established fact is the strong dependence of nuclear reaction calculations on the choice of the primary interaction. Of course, comparison between data and theoretical calculations are strongly potential-dependent. So, the choice of an appropriate nuclear bare interaction between two colliding nuclei, although it is a difficult task, is a crucial step in the data interpretation. As one has not direct access to the true bare potential, some procedures have been developed in order to constrain the choice of the bare potential to be used. The first procedure is the analysis of the elastic scattering data within the context of an optical potential, where an imaginary potential is added to the real potential, in order to take into account the flux deviated from the elastic channel. The optical potential that gives the best fit to the elastic scattering data is then used to describe other reaction channels, even in coupled channel calculations including inelastic and transfer reactions in the coupling matrix. However, this kind of calculation suffers from several inconsistencies. Another procedure that has been widely used to obtain the bare potential is the fit of the high-energy fusion data by a single barrier penetration model (BPM). However this method also has its uncertainties, since there might be channels that hinder the fusion cross section at energies near and above the Coulomb barrier. Hence, the bare potential extracted through this method can be contaminated by different processes. The derivation of experimental barrier distributions probably is the

Intercellular signaling through secreted proteins induces free-energy gradient-directed cell movement.

Science.gov (United States)

Kravchenko-Balasha, Nataly; Shin, Young Shik; Sutherland, Alex; Levine, R D; Heath, James R

2016-05-17

Controlling cell migration is important in tissue engineering and medicine. Cell motility depends on factors such as nutrient concentration gradients and soluble factor signaling. In particular, cell-cell signaling can depend on cell-cell separation distance and can influence cellular arrangements in bulk cultures. Here, we seek a physical-based approach, which identifies a potential governed by cell-cell signaling that induces a directed cell-cell motion. A single-cell barcode chip (SCBC) was used to experimentally interrogate secreted proteins in hundreds of isolated glioblastoma brain cancer cell pairs and to monitor their relative motions over time. We used these trajectories to identify a range of cell-cell separation distances where the signaling was most stable. We then used a thermodynamics-motivated analysis of secreted protein levels to characterize free-energy changes for different cell-cell distances. We show that glioblastoma cell-cell movement can be described as Brownian motion biased by cell-cell potential. To demonstrate that the free-energy potential as determined by the signaling is the driver of motion, we inhibited two proteins most involved in maintaining the free-energy gradient. Following inhibition, cell pairs showed an essentially random Brownian motion, similar to the case for untreated, isolated single cells.

Energy development potential: An analysis of Brazil

International Nuclear Information System (INIS)

Perobelli, Fernando Salgueiro; Oliveira, Caio Cézar Calheiros de

2013-01-01

This paper develops an indicator for the energy development potential (EDP) of 27 Brazilian states. This indicator uses data on a state's infrastructure and its supply of and demand for energy. The indicator measures the data for three periods: the first part of the 1990s, which is a period of low economic growth; the first part of the 2000s, which is a period of high economic growth but with a historical crisis in the Brazilian energy sector; and 2009–2011, which is a period of economic growth after the energy crisis. Using a factor analysis, we are able to identify three factors for EDP. They are the demand for energy, the supply of renewable energy, and the supply of nonrenewable energy. We use these factors to classify the Brazilian states according to their EDP and to perform an exploratory spatial data analysis (ESDA) by using the Moran indicators and the local indicators of spatial association (LISA). - Highlights: • This paper deals with the spatial dimension of the Brazilian energy sector. • We construct an index of the energy development potential for Brazilian states. • Energy issues are defined over time and space, thus have spatial dimensions. • The spatial results show that there are two well-defined spatial patterns

Effects of seed cryopreservation, stratification and scarification on germination for five rare species of pitcher plants.

Science.gov (United States)

Khanna, Sruti; Jenkins, Heather; Bucalo, Kylie; Determann, Ron O; Cruse-Sanders, Jennifer M; Pullman, Gerald S

2014-01-01

Habitat loss and over collection have caused North American pitcher plants to become rare, including U.S. federally endangered Sarracenia alabamensis and S. oreophila, and S. leucophylla, S. psittacina and S. purpurea spp. venosa, endangered in several states. To develop reliable seed cryopreservation protocols for endangered Sarracenia species enabling similar germination percentages before and after storage in liquid nitrogen (LN) either in vivo or using in vitro tools. Seed germination pre- and post-cryopreservation were compared following seed drying with germination in soil, aseptic environment with wet filter paper or enriched medium, and using scarification or stratification for dormancy removal. After cryostorage, germination in vitro (1/6- or 1/3-strength MS medium) increased compared to germination on peat moss. Germination pre- and post-cryopreservation was similar for S. alabamensis and S. oreophila when seeds were stratified and grown in vitro. S. leucophylla and S. psittacina also showed high germination after cryopreservation when germinated on medium following stratification. Rapid liquid nitrogen exposure and rewarming induced seed coat cracking that damaged seeds, likely allowing internal damage during acid scarification and microbial entry during germination in non-sterile environments.

Innovative Basis of Research of Energy-Efficient Potential and Effectiveness of Renewable Energy Sources

OpenAIRE

Hasanov Seymur Latif oglu; Hasanov Elnur Latif oglu

2018-01-01

In recent years, countries of the world have been trying to attract new energy sources (wind, sun, biogas, waves, drainage, non-conventional energy sources such as hydroelectric power of small rivers) in their fuel-energy balance. Azerbaijan has renewable natural resources, favorable for its energy-efficient potential, according to the amount of sunny and windy days. In this article was given total information about renewable energy potential of Azerbaijan Republic. In this article we use inf...

Morse potential, symmetric Morse potential and bracketed bound-state energies

Czech Academy of Sciences Publication Activity Database

Znojil, Miloslav

2016-01-01

Roč. 31, č. 14 (2016), s. 1650088 ISSN 0217-7323 R&D Projects: GA ČR GA16-22945S Institutional support: RVO:61389005 Keywords : quantum bound states * special functions * Morse potential * symmetrized Morse potential * upper and lower energy estimates * computer-assisted symbolic manipulations Subject RIV: BE - Theoretical Physics Impact factor: 1.165, year: 2016

The radial shapes of intermediate energy microscopic optical potentials

International Nuclear Information System (INIS)

Shen Qingbiao; Wang Chang; Tian Ye; Zhuo Yizhong

1984-01-01

The radial shapes of intermediate energy proton microscopic optical potentials of 40 Ca are calculated with nuclear matter approach by Skyrme interactions. The calculated results show that the real central potential in central region of nucleus changes from attractive to repulsive when the energy of incident nucleon is above 150 MeV and appears apparently a 'wine-bottle-bottom' shape in the transition energy region (from 150 MeV to 300 MeV). This tendency is consistent with empirical optical potential obtained through fitting experiments and microscopic optical potential calculated with relativistic mean field theory as well as with the BHF theory. The calculated imaginary part of the microscopic optical potential changes from the dominant surface absorption into the volume absorption and its absolute value become larger as energy increases. The effects of Skyrme force parameters to the radial shape of the calculated microscopic optical potential are analysed in detail

Inducement and responsibility in the energy turnaround

International Nuclear Information System (INIS)

Loewer, Wolfgang

2013-01-01

The book includes several contributions concerning the Bonn discussion on energy legislation (volume 7): inducement and responsibility -in terms of constitutional law; between Europe and re-regulation - what is the regulation framework? Continuity requirement as legislative action directive; the future of the nuclear fuel tax after the nuclear phaseout - problems of the constitutional finance and the European tax legislation, strategy and energy markets; regulatory challenges in the realization of the energy turnaround policy.

Combustion stratification study of partially premixed combustion using Fourier transform analysis of OH* chemiluminescence images

KAUST Repository

Izadi Najafabadi, Mohammad; Somers, Bart; Johansson, Bengt; Dam, Nico

2017-01-01

A relatively high level of stratification (qualitatively: lack of homogeneity) is one of the main advantages of partially premixed combustion over the homogeneous charge compression ignition concept. Stratification can smooth the heat release rate

Predictive features of CT for risk stratifications in patients with primary gastrointestinal stromal tumour

International Nuclear Information System (INIS)

Zhou, Cuiping; Zhang, Xiang; Duan, Xiaohui; Hu, Huijun; Wang, Dongye; Shen, Jun

2016-01-01

To determine the predictive CT imaging features for risk stratifications in patients with primary gastrointestinal stromal tumours (GISTs). One hundred and twenty-nine patients with histologically confirmed primary GISTs (diameter >2 cm) were enrolled. CT imaging features were reviewed. Tumour risk stratifications were determined according to the 2008 NIH criteria where GISTs were classified into four categories according to the tumour size, location, mitosis count, and tumour rupture. The association between risk stratifications and CT features was analyzed using univariate analysis, followed by multinomial logistic regression and receiver operating characteristic (ROC) curve analysis. CT imaging features including tumour margin, size, shape, tumour growth pattern, direct organ invasion, necrosis, enlarged vessels feeding or draining the mass (EVFDM), lymphadenopathy, and contrast enhancement pattern were associated with the risk stratifications, as determined by univariate analysis (P < 0.05). Only lesion size, growth pattern and EVFDM remained independent risk factors in multinomial logistic regression analysis (OR = 3.480-100.384). ROC curve analysis showed that the area under curve of the obtained multinomial logistic regression model was 0.806 (95 % CI: 0.727-0.885). CT features including lesion size, tumour growth pattern, and EVFDM were predictors of the risk stratifications for GIST. (orig.)

A superconductor electromechanical oscillator and its potential application in energy storage

International Nuclear Information System (INIS)

Schilling, Osvaldo F

2004-01-01

We discuss theoretically the properties of an electromechanical oscillating system whose operation is based upon the cyclic conservative conversion between gravitational potential, kinetic and magnetic energies. The system consists of a superconducting coil subjected to a constant external force and to magnetic fields. The coil oscillates and has induced in it a rectified electrical current whose magnitude may reach hundreds of amperes. The design differs from that of most conventional superconductor machines since the motion is linear (and practically unnoticeable depending on frequency) rather than rotatory and it does not involve high speeds. Furthermore, there is no need for an external electrical power source to start up the system. We also show that the losses for such a system can be made extremely small for certain operational conditions, so that by reaching and keeping resonance the system's main application should be in the generation and storage of electromagnetic energy. (rapid communication)

Inducing repetitive action potential firing in neurons via synthesized photoresponsive nanoscale cellular prostheses.

Science.gov (United States)

Lu, Siyuan; Madhukar, Anupam

2013-02-01

Recently we reported an analysis that examined the potential of synthesized photovoltaic functional abiotic nanosystems (PVFANs) to modulate membrane potential and activate action potential firing in neurons. Here we extend the analysis to delineate the requirements on the electronic energy levels and the attendant photophysical properties of the PVFANs to induce repetitive action potential under continuous light, a capability essential for the proposed potential application of PVFANs as retinal cellular prostheses to compensate for loss of photoreceptors. We find that repetitive action potential firing demands two basic characteristics in the electronic response of the PVFANs: an exponential dependence of the PVFAN excited state decay rate on the membrane potential and a three-state system such that, following photon absorption, the electron decay from the excited state to the ground state is via intermediate state(s) whose lifetime is comparable to the refractory time following an action potential. In this study, the potential of synthetic photovoltaic functional abiotic nanosystems (PVFANs) is examined under continuous light to modulate membrane potential and activate action potential firing in neurons with the proposed potential application of PVFANs as retinal cellular prostheses. Copyright © 2013 Elsevier Inc. All rights reserved.

Potential contribution of biomass to the sustainable energy development

International Nuclear Information System (INIS)

Demirbas, M. Fatih; Balat, Mustafa; Balat, Havva

2009-01-01

Biomass is a renewable energy source and its importance will increase as national energy policy and strategy focuses more heavily on renewable sources and conservation. Biomass is considered the renewable energy source with the highest potential to contribute to the energy needs of modern society for both the industrialized and developing countries worldwide. The most important biomass energy sources are wood and wood wastes, agricultural crops and their waste byproducts, municipal solid waste, animal wastes, waste from food processing, and aquatic plants and algae. Biomass is one potential source of renewable energy and the conversion of plant material into a suitable form of energy, usually electricity or as a fuel for an internal combustion engine, can be achieved using a number of different routes, each with specific pros and cons. Currently, much research has been focused on sustainable and environmental friendly energy from biomass to replace conventional fossil fuels. The main objective of the present study is to investigate global potential and use of biomass energy and its contribution to the sustainable energy development by presenting its historical development.

Correlation energy generating potentials for molecular hydrogen

International Nuclear Information System (INIS)

Sharma, B.S.; Thakkar, A.J.

1985-01-01

A variety of local correlation energy functionals are currently in use. All of them depend, to some extent, on modeling the correlation energy of a homogeneous electron fluid. Since atomic and molecular charge densities are neither uniform nor slowly varying, it is important to attempt to use known high accuracy wave functions to learn about correlation energy functionals appropriate to such systems. We have extended the definition of the correlation energy generating potentials V/sub c/ introduced by Ros. A charge density response to correlation has been allowed for by inclusion of an electron--nuclear component V/sup e/n/sub c/ in addition to the electron--electron component V/sup e/e/sub c/. Two different definitions of V/sup e/n/sub c/ are given. We present the first calculations of V/sub c/ for a molecular system: H 2 . The results show that V/sup e/n/sub c/, in either definition, is by no means negligible. Moreover, V/sup e/e/sub c/ and both forms of V/sup e/n/sub c/ show significant nonlocal dependence on the charge density. Calculations with ten different model correlation energy functionals show that none of them is particularly sensitive to the charge density. However, they are quite sensitive to the parametrization of the electron fluid correlation energy. The schemes which include self-interaction corrections (SIC) are found to be superior to those of Kohn--Sham type. The correlation energy generating potentials implied by the SIC type and empirical correlation energy functionals are found to correspond roughly to averages of one of the accurate potentials

Environmental stratification framework and water-quality monitoring design strategy for the Islamic Republic of Mauritania, Africa

Science.gov (United States)

Friedel, Michael J.

2008-01-01

Mauritania anticipates an increase in mining activities throughout the country and into the foreseeable future. Because mining-induced changes in the landscape are likely to affect their limited ground-water resources and sensitive aquatic ecosystems, a water-quality assessment program was designed for Mauritania that is based on a nationally consistent environmental stratification framework. The primary objectives of this program are to ensure that the environmental monitoring systems can quantify near real-time changes in surface-water chemistry at a local scale, and quantify intermediate- to long-term changes in groundwater and aquatic ecosystems over multiple scales.

ASSESSMENT OF STELLAR STRATIFICATION IN THREE YOUNG STAR CLUSTERS IN THE LARGE MAGELLANIC CLOUD

International Nuclear Information System (INIS)

Gouliermis, Dimitrios A.; Rochau, Boyke; Mackey, Dougal; Xin Yu

2010-01-01

We present a comprehensive study of stellar stratification in young star clusters in the Large Magellanic Cloud (LMC). We apply our recently developed effective radius method for the assessment of stellar stratification on imaging data obtained with the Advanced Camera for Surveys of three young LMC clusters to characterize the phenomenon and develop a comparative scheme for its assessment in such clusters. The clusters of our sample, NGC 1983, NGC 2002, and NGC 2010, are selected on the basis of their youthfulness, and their variety in appearance, structure, stellar content, and surrounding stellar ambient. Our photometry is complete for magnitudes down to m 814 ≅ 23 mag, allowing the calculation of the structural parameters of the clusters, the estimation of their ages, and the determination of their stellar content. Our study shows that each cluster in our sample demonstrates stellar stratification in a quite different manner and at different degree from the others. Specifically, NGC 1983 shows partial segregation, with the effective radius increasing with fainter magnitudes only for the faintest stars of the cluster. Our method on NGC 2002 provides evidence of strong stellar stratification for both bright and faint stars; the cluster demonstrates the phenomenon with the highest degree in the sample. Finally, NGC 2010 is not segregated, as its bright stellar content is not centrally concentrated, the relation of effective radius to magnitude for stars of intermediate brightness is rather flat, and we find no evidence of stratification for its faintest stars. For the parameterization of the phenomenon of stellar stratification and its quantitative comparison among these clusters, we propose the slope derived from the change in the effective radius over the corresponding magnitude range as indicative parameter of the degree of stratification in the clusters. A positive value of this slope indicates mass segregation in the cluster, while a negative or zero value

Energy efficiency improvement potentials for the cement industry in Ethiopia

International Nuclear Information System (INIS)

Tesema, Gudise; Worrell, Ernst

2015-01-01

The cement sector is one of the fast growing economic sectors in Ethiopia. In 2010, it consumed 7 PJ of primary energy. We evaluate the potential for energy savings and CO_2 emission reductions. We start by benchmarking the energy performance of 8 operating plants in 2010, and 12 plants under construction. The benchmarking shows that the energy intensity of local cement facilities is high, when compared to the international best practice, indicating a significant potential for energy efficiency improvement. The average electricity intensity and fuel intensity of the operating plants is 34% and 36% higher. For plants under construction, electricity use is 36% and fuel use 27% higher. We identified 26 energy efficiency measures. By constructing energy conservation supply curves, the energy-efficiency improvement potential is assessed. For the 8 operating plants in 2010, the cost-effective energy savings equal 11 GWh electricity and 1.2 PJ fuel, resulting in 0.1 Mt CO_2 emissions reduction. For the 20 cement plants expected to be in operation by 2020, the cost-effective energy saving potentials is 159 GWh for electricity and 7.2 PJ for fuel, reducing CO_2 emissions by about 0.6 Mt. We discuss key barriers and recommendations to realize energy savings. - Highlights: • The cement sector in Ethiopia is growing rapidly, using mainly imported fuels. • Benchmarking demonstrates a significant potential for energy efficiency improvement. • A large part of the energy efficiency potential can be achieved cost-effectively. • Ethiopia should ban the construction of obsolete vertical shaft kilns.

How do policies for efficient energy use in the household sector induce energy-efficiency innovation? An evaluation of European countries

International Nuclear Information System (INIS)

Girod, Bastien; Stucki, Tobias; Woerter, Martin

2017-01-01

Research on innovation induced by climate-mitigation policy has been focused predominantly on the supply side of the energy system. Despite considerable climate-mitigation potential on the demand side, less attention is given to the innovation effect of policies addressing the household sector. Based on a comprehensive data set, including 550 policy measures over 30 years (1980–2009) and covering 21 European countries, we find—based on econometric estimations—that policies targeting efficient energy use in the household sector significantly increase the number of patented energy-efficiency inventions. A comparison of the different policy types reveals a particularly strong influence from financial subsidies and energy labels. The results indicate that policies supporting early market adoption of energy-efficient technologies are effective in fostering innovation. - Highlights: • We evaluate the impact of energy-efficiency policy on energy-efficiency innovation. • The dataset covers patents and policies for 1980–2009 in 21 European countries. • Household policies show a positive influence on innovation activity (patented inventions). • The influence is most pronounced for financial subsidies and energy labels.

U.S. Building-Sector Energy Efficiency Potential

Energy Technology Data Exchange (ETDEWEB)

Brown, Rich; Borgeson, Sam; Koomey, Jon; Biermayer, Peter

2008-09-30

This paper presents an estimate of the potential for energy efficiency improvements in the U.S. building sector by 2030. The analysis uses the Energy Information Administration's AEO 2007 Reference Case as a business-as-usual (BAU) scenario, and applies percentage savings estimates by end use drawn from several prior efficiency potential studies. These prior studies include the U.S. Department of Energy's Scenarios for a Clean Energy Future (CEF) study and a recent study of natural gas savings potential in New York state. For a few end uses for which savings estimates are not readily available, the LBNL study team compiled technical data to estimate savings percentages and costs of conserved energy. The analysis shows that for electricity use in buildings, approximately one-third of the BAU consumption can be saved at a cost of conserved energy of 2.7 cents/kWh (all values in 2007 dollars), while for natural gas approximately the same percentage savings is possible at a cost of between 2.5 and 6.9 $/million Btu. This cost-effective level of savings results in national annual energy bill savings in 2030 of nearly $170 billion. To achieve these savings, the cumulative capital investment needed between 2010 and 2030 is about $440 billion, which translates to a 2-1/2 year simple payback period, or savings over the life of the measures that are nearly 3.5 times larger than the investment required (i.e., a benefit-cost ratio of 3.5).

Schematic Harder–Narasimhan stratification for families of principal ...

Indian Academy of Sciences (India)

Home; Journals; Proceedings – Mathematical Sciences; Volume 124; Issue 3. Schematic Harder–Narasimhan Stratification for Families of Principal Bundles ... Author Affiliations. Sudarshan Gurjar1 Nitin Nitsure1. School of Mathematics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India ...

Wind energy potential in India

International Nuclear Information System (INIS)

Rangarajan, S.

1995-01-01

Though located in the tropics, India is endowed with substantial wind resources because of its unique geographical location which gets fully exposed to both the south-west and north-east monsoon winds. The westerly winds of the south-west monsoons provide bulk of the wind potential. Areas with mean annual wind speed exceeding 18 k mph and areas with mean annual power density greater than 140 W/m 2 have been identified using the wind data collected by the wind monitoring project funded by the Ministry of Non-conventional Energy Sources (MNES). Seasonal variations in wind speed at selected locations are discussed as also the frequency distribution of hourly wind speed. Annual capacity factors for 250 kW wind electric generators have been calculated for several typical locations. A good linear correlation has been found between mean annual wind speed and mean annual capacity factor. A method is described for assessing wind potential over an extended region where adequate data is available. It is shown that the combined wind energy potential over five selected areas of limited extent in Gujarat, Andhra Pradesh and Tamil Nadu alone amounts to 22,000 MW under the assumption of 20 per cent land availability for installing wind farms. For a higher percentage of land availability, the potential will be correspondingly higher. (author). 12 refs., 6 figs., 3 tabs

Research on potential user identification model for electric energy substitution

Science.gov (United States)

Xia, Huaijian; Chen, Meiling; Lin, Haiying; Yang, Shuo; Miao, Bo; Zhu, Xinzhi

2018-01-01

The implementation of energy substitution plays an important role in promoting the development of energy conservation and emission reduction in china. Energy service management platform of alternative energy users based on the data in the enterprise production value, product output, coal and other energy consumption as a potential evaluation index, using principal component analysis model to simplify the formation of characteristic index, comprehensive index contains the original variables, and using fuzzy clustering model for the same industry user’s flexible classification. The comprehensive index number and user clustering classification based on constructed particle optimization neural network classification model based on the user, user can replace electric potential prediction. The results of an example show that the model can effectively predict the potential of users’ energy potential.

Morphine potentiates seizures induced by GABA antagonists and attenuates seizures induced by electroshock in the rat.

Science.gov (United States)

Foote, F; Gale, K

1983-11-25

In a naloxone-reversible, dose-dependent manner, morphine (10-50 mg/kg i.p.) protected against seizures induced by maximal electroshock and increased the incidence and severity of seizures induced by bicuculline, in rats. Morphine also potentiated seizures induced by isoniazid and by picrotoxin. Thus, opiate activity influences the expression of seizures in contrasting ways depending upon the mode of seizure induction. Since morphine consistently potentiated seizures induced by interference with GABA transmission, it appears that GABAergic systems may be of particular significance for the elucidation of the varied effects of morphine on seizure susceptibility.

PPOOLEX experiments on stratification and mixing in the wet well pool

International Nuclear Information System (INIS)

Laine, J.; Puustinen, M.; Raesaenen, A.; Tanskanen, V.

2011-03-01

This report summarizes the results of the thermal stratification and mixing experiments carried out in 2010 with the scaled down, two compartment PPOOLEX test facility designed and constructed at LUT. Steam was blown into the thermally insulated dry well compartment and from there through the DN200 vertical blowdown pipe to the condensation pool filled with sub-cooled water. The main purpose of the experiment series was to generate verification data for evaluating the capability of GOTHIC and APROS codes to predict stratification and mixing phenomena. Another objective was to test the sound velocity measurement system. Altogether five experiments were carried out. The experiments consisted of a small steam flow rate stratification period and of a mixing period with continuously or stepwise increasing flow rate. The dry well structures were heated up to the level of approximately 90 deg. C before the actual experiments. The initial water bulk temperature was 20 deg. C. When the steam flow rate was low enough (typically ∼100-150 g/s) temperatures below the blowdown pipe outlet remained constant while increasing heat-up occurred towards the pool surface layers indicating strong thermal stratification of the wet well pool water. During the stratification period the highest measured temperature difference between pool bottom and surface was approximately 40 deg. C. During the mixing period total mixing of the pool volume was not achieved in any of the experiments. The bottom layers heated up significantly but never reached the same temperature as the topmost layers. The lowest measured temperature difference between the pool bottom and surface was 7-8 deg. C. According to the test results, it seems that a small void fraction doesn't have an effect on the speed of sound in water and that the acquired sound velocity measurement system cannot be used for the estimation of void fraction in the wet well water pool. However, more tests on this issue have to be executed

PPOOLEX experiments on stratification and mixing in the wet well pool

Energy Technology Data Exchange (ETDEWEB)

Laine, J.; Puustinen, M.; Raesaenen, A.; Tanskanen, V. (Lappeenranta Univ. of Technology, Nuclear Safety Research Unit (Finland))

2011-03-15

This report summarizes the results of the thermal stratification and mixing experiments carried out in 2010 with the scaled down, two compartment PPOOLEX test facility designed and constructed at LUT. Steam was blown into the thermally insulated dry well compartment and from there through the DN200 vertical blowdown pipe to the condensation pool filled with sub-cooled water. The main purpose of the experiment series was to generate verification data for evaluating the capability of GOTHIC and APROS codes to predict stratification and mixing phenomena. Another objective was to test the sound velocity measurement system. Altogether five experiments were carried out. The experiments consisted of a small steam flow rate stratification period and of a mixing period with continuously or stepwise increasing flow rate. The dry well structures were heated up to the level of approximately 90 deg. C before the actual experiments. The initial water bulk temperature was 20 deg. C. When the steam flow rate was low enough (typically approx100-150 g/s) temperatures below the blowdown pipe outlet remained constant while increasing heat-up occurred towards the pool surface layers indicating strong thermal stratification of the wet well pool water. During the stratification period the highest measured temperature difference between pool bottom and surface was approximately 40 deg. C. During the mixing period total mixing of the pool volume was not achieved in any of the experiments. The bottom layers heated up significantly but never reached the same temperature as the topmost layers. The lowest measured temperature difference between the pool bottom and surface was 7-8 deg. C. According to the test results, it seems that a small void fraction doesn't have an effect on the speed of sound in water and that the acquired sound velocity measurement system cannot be used for the estimation of void fraction in the wet well water pool. However, more tests on this issue have to be

The influence of viscosity stratification on boundary-layer turbulence

Science.gov (United States)

Lee, Jin; Jung, Seo Yoon; Sung, Hyung Jin; Zaki, Tamer A.

2012-11-01

Direct numerical simulations of turbulent flows over isothermally-heated walls were performed to investigate the influence of viscosity stratification on boundary-layer turbulence and drag. The adopted model for temperature-dependent viscosity was typical of water. The free-stream temperature was set to 30°C, and two wall temperatures, 70°C and 99°C, were simulated. In the heated flows, the mean shear-rate is enhanced near the wall and reduced in the buffer region, which induces a reduction in turbulence production. On the other hand, the turbulence dissipation is enhanced near the wall, despite the the reduction in fluid viscosity. The higher dissipation is attributed to a decrease in the smallest length scales and near-wall fine-scale motions. The combined effect of the reduced production and enhanced dissipation leads to lower Reynolds shear stresses and, as a result, reduction of the skin-friction coefficient. Supported by the Engineering and Physical Sciences Research Council (Grant EP/F034997/1) and partially supported by the Erasmus Mundus Build on Euro-Asian Mobility (EM-BEAM) programme.

Relating sedimentary processes in the Bagnold Dunes to the development of crater basin aeolian stratification

Science.gov (United States)

Ewing, R. C.; Lapotre, M. G. A.; Lewis, K. W.; Day, M. D.; Stein, N.; Rubin, D. M.; Sullivan, R. J., Jr.; Banham, S.; Thomas, N. M.; Lamb, M. P.; Gupta, S.; Fischer, W. W.

2017-12-01

Wind-blown sand dunes are ubiquitous on the surface of Mars and are a recognized component of the martian stratigraphic record. Our current knowledge of the aeolian sedimentary processes that determine dune morphology, drive dune dynamics, and create aeolian cross-stratification are based upon orbital studies of ripple and dune morphodynamics, rover observations of stratification on Mars, Earth analogs, and experimental and theoretical studies of sand movement under martian conditions. Exploration of the Bagnold Dunes by the Curiosity Rover in Gale Crater, Mars provided the first opportunity to make in situ observations of martian dunes from the grain-to-dune scale. We used the suite of cameras on Curiosity, including Navigation Camera, Mast Camera, and Mars Hand Lens Imager. We measured grainsize and identified sedimentary processes similar to processes on terrestrial dunes, such as grainfall, grainflow, and impact ripples. Impact ripple grainsize had a median of 0.103 mm. Measurements of grainflow slopes indicate a relaxation angle of 29° and grainfall slopes indicate critical angles of at least 32°. Dissimilar to terrestrial dunes, large, meter-scale ripples form on all slopes of the dunes. The ripples form both sinuous and linear crestlines, have symmetric and asymmetric profiles, range in height between 12cm and 28cm, and host grainfall, grainflow, and impact ripples. The largest ripples are interpreted to integrate the annual wind cycle within the crater, whereas smaller large ripples and impact ripples form or reorient to shorter term wind cycling. Assessment of sedimentary processes in combination with dune type across the Bagnold Dunes shows that dune-field pattern development in response to a complex crater-basin wind regime dictates the distribution of geomorphic processes. From a stratigraphic perspective, zones of highest potential accumulation correlate with zones of wind convergence, which produce complex winds and dune field patterns thereby

A snapshot of geothermal energy potential and utilization in Turkey

International Nuclear Information System (INIS)

Erdogdu, Erkan

2009-01-01

Turkey is one of the countries with significant potential in geothermal energy. It is estimated that if Turkey utilizes all of her geothermal potential, she can meet 14% of her total energy need (heat and electricity) from geothermal sources. Therefore, today geothermal energy is an attractive option in Turkey to replace fossil fuels. Besides, increase in negative effects of fossil fuels on the environment has forced many countries, including Turkey, to use renewable energy sources. Also, Turkey is an energy importing country; more than two-thirds of her energy requirement is supplied by imports. In this context, geothermal energy appears to be one of the most efficient and effective solutions for sustainable energy development and environmental pollution prevention in Turkey. Since geothermal energy will be used more and more in the future, its current potential, usage, and assessment in Turkey is the focus of the present study. The paper not only presents a review of the potential and utilization of the geothermal energy in Turkey but also provides some guidelines for policy makers. (author)

Modelling of containment atmosphere mixing and stratification experiment using CFD approach

International Nuclear Information System (INIS)

Ivo Kljenak; Miroslav Babic; Borut Mavko; Ivan Bajsic

2005-01-01

An experiment on containment atmosphere mixing and stratification, which was originally performed in the TOSQAN facility in Saclay (France), was simulated with the Computational Fluid Dynamics code CFX. The TOSQAN facility consists of a large cylindrical vessel in which gases are injected. In the considered experiment, steam, air and helium were injected during different phases of the experiment, with steam condensing on vessel walls. Three intermediate steady states, which were obtained with different boundary conditions, were simulated independently. A two-dimensional axisymmetric model of the TOSQAN vessel for the CFX4.4 code was developed. The flow in the simulation domain was modelled as single-phase. Steam condensation on vessel walls was modelled as a sink of mass and energy. Calculated profiles of temperature, steam concentration, and velocity components are compared to experimental results. (authors)

Biomass energy potential in Brazil. Country study

Energy Technology Data Exchange (ETDEWEB)

Moreira, J [Biomass Users Network-Brazil Regional Office, Sao Paulo (Brazil)

1995-12-01

The present paper was prepared as a country study about the biomass potential for energy production in Brazil. Information and analysis of the most relevant biomass energy sources and their potential are presented in six chapters. Ethanol fuel, sugar-cane bagasse, charcoal, vegetable oil, firewood and other biomass-derived fuels are the objects of a historical review, in addition to the presentation of state-of-the-art technologies, economic analysis and discussion of relevant social and environmental issues related to their production and use. Wherever possible, an evaluation, from the available sources of information and based on the author`s knowledge, is performed to access future perspectives of each biomass energy source. Brazil is a country where more than half of the energy consumed is provided from renewable sources of energy, and biomass provides 28% of the primary energy consumption. Its large extension, almost all located in the tropical and rainy region, provides an excellent site for large-scale biomass production, which is a necessity if biomass is to be used to supply a significant part of future energy demand. Even so, deforestation has occurred and is occurring in the country, and the issue is discussed and explained as mainly the result of non-energy causes or the use of old and outdated technologies for energy production. (author) 115 refs, figs, tabs

Biomass energy potential in Brazil. Country study

International Nuclear Information System (INIS)

Moreira, J.

1995-01-01

The present paper was prepared as a country study about the biomass potential for energy production in Brazil. Information and analysis of the most relevant biomass energy sources and their potential are presented in six chapters. Ethanol fuel, sugar-cane bagasse, charcoal, vegetable oil, firewood and other biomass-derived fuels are the objects of a historical review, in addition to the presentation of state-of-the-art technologies, economic analysis and discussion of relevant social and environmental issues related to their production and use. Wherever possible, an evaluation, from the available sources of information and based on the author's knowledge, is performed to access future perspectives of each biomass energy source. Brazil is a country where more than half of the energy consumed is provided from renewable sources of energy, and biomass provides 28% of the primary energy consumption. Its large extension, almost all located in the tropical and rainy region, provides an excellent site for large-scale biomass production, which is a necessity if biomass is to be used to supply a significant part of future energy demand. Even so, deforestation has occurred and is occurring in the country, and the issue is discussed and explained as mainly the result of non-energy causes or the use of old and outdated technologies for energy production. (author)

Renewable energy potential in Southern Africa: conference proceedings

International Nuclear Information System (INIS)

1986-01-01

This conference, held in Cape Town from 8-10 September 1986, consist of many papers discussing the renewalble energy potential in Southern Africa. The papers delivered at the conference include topics such as wind energy, ocean energy, hydroelectric resources, solar resources, wave energy, agroforestry, fuelwood, hydrogen energy and the production of energy from biomass. Several papers were delivered on solar water heating and one on nuclear vs renewable energy

Properties of Augmented Kohn-Sham Potential for Energy as Simple Sum of Orbital Energies.

Science.gov (United States)

Zahariev, Federico; Levy, Mel

2017-01-12

A recent modification to the traditional Kohn-Sham method ( Levy , M. ; Zahariev , F. Phys. Rev. Lett. 2014 , 113 , 113002 ; Levy , M. ; Zahariev , F. Mol. Phys. 2016 , 114 , 1162 - 1164 ), which gives the ground-state energy as a direct sum of the occupied orbital energies, is discussed and its properties are numerically illustrated on representative atoms and ions. It is observed that current approximate density functionals tend to give surprisingly small errors for the highest occupied orbital energies that are obtained with the augmented potential. The appropriately shifted Kohn-Sham potential is the basic object within this direct-energy Kohn-Sham method and needs to be approximated. To facilitate approximations, several constraints to the augmented Kohn-Sham potential are presented.

Effects of stratification and fluctuations on sound propagation in the deep ocean

International Nuclear Information System (INIS)

March, R.H.

1979-01-01

It is noted that even in a homogeneous ocean, the effects of non-thermal noise and sound absorption limit the maximum effective range of detection of acoustic signals from particle cascades to distances of 2 to 10 kilometers, depending on the surface conditions prevailing and the directional characteristics of the detector. In the present paper, the effects of stratification and fluctuations in the sound velocity profile in the deep ocean over distances of this order are examined. Attention is given to two effects of potential significance, refraction and scintillation. It is found that neither effect has any significant consequences at ranges of less than 10 km

Estimation of energy potential of agricultural enterprise biomass

Directory of Open Access Journals (Sweden)

Lypchuk Vasyl

2017-01-01

Full Text Available Bioenergetics (obtaining of energy from biomass is one of innovative directions in energy branch of Ukraine. Correct and reliable estimation of biomass potential is essential for efficient use of it. The article reveals the issue of estimation of potential of biomass, obtained from byproducts of crop production and animal breeding, which can be used for power supply of agricultural enterprises. The given analysis was carried with application of common methodological fundamentals, revealed in the estimation of production structure of agricultural enterprises, structure of land employment, efficiency of crops growing, indicators of output of main and by-products, as well as normative (standard parameters of power output of energy raw material in relation to the chosen technology of its utilization. Results of the research prove high energy potential of byproducts of crop production and animal breeding at all of the studied enterprises, which should force its practical use.

Water Stratification Raster Images for the Gulf of Maine

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This geodatabase contains seasonal water stratification raster images for the Gulf of Maine. They were created by interpolating water density (sigma t) values at 0...

Energy conservation potential in Taiwanese textile industry

International Nuclear Information System (INIS)

Hong, Gui-Bing; Su, Te-Li; Lee, Jenq-Daw; Hsu, Tsung-Chi; Chen, Hua-Wei

2010-01-01

Since Taiwan lacks sufficient self-produced energy, increasing energy efficiency and energy savings are essential aspects of Taiwan's energy policy. This work summarizes the energy savings implemented by 303 firms in Taiwan's textile industry from the on-line Energy Declaration System in 2008. It was found that the total implemented energy savings amounted to 46,074 ton of oil equivalent (TOE). The energy saving was equivalent to 94,614 MWh of electricity, 23,686 kl of fuel oil and 4887 ton of fuel coal. It represented a potential reduction of 143,669 ton in carbon dioxide emissions, equivalent to the annual carbon dioxide absorption capacity of a 3848 ha plantation forest. This study summarizes energy-saving measures for energy users and identifies the areas for making energy saving to provide an energy efficiency baseline.

The potential of renewable energy

Energy Technology Data Exchange (ETDEWEB)

1990-03-01

On June 27 and 28, 1989, the US Department of Energy (DOE) national laboratories were convened to discuss plans for the development of a National Energy Strategy (NES) and, in particular, the analytic needs in support of NES that could be addressed by the laboratories. As a result of that meeting, interlaboratory teams were formed to produce analytic white papers on key topics, and a lead laboratory was designated for each core laboratory team. The broad-ranging renewables assignment is summarized by the following issue statement from the Office of Policy, Planning and Analysis: to what extent can renewable energy technologies contribute to diversifying sources of energy supply What are the major barriers to greater renewable energy use and what is the potential timing of widespread commercialization for various categories of applications This report presents the results of the intensive activity initiated by the June 1989 meeting to produce a white paper on renewable energy. Scores of scientists, analysts, and engineers in the five core laboratories gave generously of their time over the past eight months to produce this document. Their generous, constructive efforts are hereby gratefully acknowledged. 126 refs., 44 figs., 32 tabs.

Assessment of renewable energy potential. Calculation model “AREP-LP”

International Nuclear Information System (INIS)

Penchev, Alexander

2011-01-01

Introduction Bulgaria is a country rich in renewable energy sources. There are all types of RES including: solar, geothermal, biomass, wind energy and hydropower. Per capita it ranks among the top in Europe. Bulgaria's target for 2020 is 16% of final consumption of electricity should be from renewable energy. To achieve this goal, the first and most important task is assessing the potential of renewable energy and its geographical distribution. Creating a database of renewable energy is essential for implementation of investment projects in this area. Key words: Renewable Energy (RES), Renewable Technologies (RET), Theoretical Potential, Technical Potential, Municipalities, Regions, Energy Planning(EP), Emission Reduction (EmR), Market Assessment (MA), Data base(DB)

EPA RE-Powering Mapper: Alternative Energy Potential at Cleanup Sites

Science.gov (United States)

The U.S. Environmental Protection Agency (EPA) Office of Land and Emergency Management??s (OLEM) Office of Communications, Partnerships and Analysis (OCPA) initiated the RE-Powering America's Land Initiative to demonstrate the enormous potential that contaminated lands, landfills, and mine sites provide for developing renewable energy in the United States. EPA developed national level site screening criteria in partnership with the U.S. Department of Energy (DOE) National Renewable Energy Laboratory (NREL) for wind, solar, biomass, and geothermal facilities. While the screening criteria demonstrate the potential to reuse contaminated land for renewable energy facilities, the criteria and data are neither designed to identify the best sites for developing renewable energy nor all-inclusive. Therefore, more detailed, site-specific analysis is necessary to identify or prioritize the best sites for developing renewable energy facilities based on the technical and economic potential. Please note that these sites were only pre-screened for renewable energy potential. The sites were not evaluated for land use constraints or current on the ground conditions. Additional research and site-specific analysis are needed to verify viability for renewable energy potential at a given site.

Statistical Support for Analysis of the Social Stratification and Economic Inequality of the Country’s Population

Directory of Open Access Journals (Sweden)

Aksyonova Irina V.

2017-12-01

Full Text Available The aim of the article is to summarize the theoretical and methodological as well as information and analytical support for statistical research of economic and social stratification in society and conduct an analysis of the differentiation of the population of Ukraine in terms of the economic component of social inequality. The theoretical and methodological level of the research is studied, and criteria for social stratification and inequalities in society, systems, models and theories of social stratification of the population are singled out. The indicators of social and economic statistics regarding the differentiation of the population by income level are considered as the research tools. As a result of the analysis it was concluded that the economic inequality of the population leads to changes in the social structure, which requires formation of a new social stratification of society. The basis of social stratification is indicators of the population well-being, which require a comprehensive study. Prospects for further research in this area are the analysis of the components of economic inequality that determine and influence the social stratification of the population of the country, the formation of the middle class, and the study of the components of the human development index as a cross-currency indicator of the socio-economic inequality of the population.

Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Pulp and Paper Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Sabine Brueske, Caroline Kramer, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. pulp and paper manufacturing. The study relies on multiple sources to estimate the energy used in six individual process areas, representing 52% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; the potential savings are then extrapolated to estimate sector-wide energy savings opportunity

The Dilemmas of Energy: Essential energy services and potentially fatal risks

Science.gov (United States)

Perkins, J. H.

2018-01-01

During their evolution, humans have made three energy transitions, each marked by the adoption of new ways of procuring energy with attendant changes in lifestyle. Modern civilization arose in the Third Energy Transition, and its major sources of energy come from coal, oil, gas, uranium, and hydropower. Unfortunately, despite its incalculable benefits, the Third Transition can’t provide sustainable energy services for the indefinite future. Climate change is the most serious problem. Criteria and standards for each of the currently available, nine primary energy sources indicate the potential feasibility of replacing most or all uses of coal, oil, gas, and uranium with hydropower, solar, wind, biomass, and geothermal. This is the Fourth Energy Transition, promotion of which is strongly supported by considerations of sustainability.

Combustion Stratification for Naphtha from CI Combustion to PPC

KAUST Repository

Vallinayagam, R.; Vedharaj, S.; An, Yanzhao; Dawood, Alaaeldin; Izadi Najafabadi, Mohammad; Somers, Bart; Johansson, Bengt

2017-01-01

This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON

The potential of new renewable energy sources in Switzerland

International Nuclear Information System (INIS)

Dietrich, P.; Kaiser, T.; Wokaun, A.

2010-01-01

This article presents and discusses the results of an evaluation made by the so-called 'Swiss Energy Trialogue' ETS on the potential offered by new renewable energy sources in Switzerland. The evaluation forecasts an important contribution to Swiss energy supply by renewable energy sources by the year 2050. The authors are of the opinion that, in spite of a considerable increase in the offers of renewable energy and the full use of energy saving potential, a discrepancy will exist between estimates of energy needs and the actual energy available from renewable resources if large-scale power generation facilities are not built. Activities proposed by the Swiss government are discussed and analysed. In particular, possible contributions to be made by renewable energy sources are examined. Suggestions made by ETS concerning possible courses of action are discussed

Analysis of agreement between cardiac risk stratification protocols applied to participants of a center for cardiac rehabilitation

Directory of Open Access Journals (Sweden)

Ana A. S. Santos

2016-01-01

Full Text Available ABSTRACT Background Cardiac risk stratification is related to the risk of the occurrence of events induced by exercise. Despite the existence of several protocols to calculate risk stratification, studies indicating that there is similarity between these protocols are still unknown. Objective To evaluate the agreement between the existing protocols on cardiac risk rating in cardiac patients. Method The records of 50 patients from a cardiac rehabilitation program were analyzed, from which the following information was extracted: age, sex, weight, height, clinical diagnosis, medical history, risk factors, associated diseases, and the results from the most recent laboratory and complementary tests performed. This information was used for risk stratification of the patients in the protocols of the American College of Sports Medicine, the Brazilian Society of Cardiology, the American Heart Association, the protocol designed by Frederic J. Pashkow, the American Association of Cardiovascular and Pulmonary Rehabilitation, the Société Française de Cardiologie, and the Sociedad Española de Cardiología. Descriptive statistics were used to characterize the sample and the analysis of agreement between the protocols was calculated using the Kappa coefficient. Differences were considered with a significance level of 5%. Results Of the 21 analyses of agreement, 12 were considered significant between the protocols used for risk classification, with nine classified as moderate and three as low. No agreements were classified as excellent. Different proportions were observed in each risk category, with significant differences between the protocols for all risk categories. Conclusion The agreements between the protocols were considered low and moderate and the risk proportions differed between protocols.

Energy strategy and mitigation potential in energy sector of the Russian federation

Energy Technology Data Exchange (ETDEWEB)

Yakovlev, A.F.; Petrov, V.N.; Chupyatov, V.P.

1996-12-31

This paper describes the mitigation potential in the Russian energy sector and presents CO{sub 2} - emission scenarios. Based on the Russian energy strategy, energy conservation potential has been estimated and three groups of energy conservation measures have been pointed out. Taking into account the economic development scenarios and the scenarios of energy consumption and energy conservation, future CO{sub 2} emission scenarios for 2000 and 2010 have been prepared. Some important characteristics of these scenarios have been presented and discussed. For the period 2000-2010 annual growth rates for CO{sub 2} emission in the Russian energy sector will not exceed 0.9-1.3 %, and emission levels in 2000 make up - 75-78 %, and in 2010 - 81-88 % of the 1990 level. For the probable scenario the CO{sub 2} emission reducing will make up about 6% and 25% (for the optimistic scenario about 16% and 31%) of CO{sub 2} emission for reference scenario in 2000 and 2010 respectively. Additional CO{sub 2} emission reducing (3-5% of domestic CO{sub 2} emission) will result from increasing share of natural gas consumption.

Arrhythmogenic Right Ventricular Cardiomyopathy: Risk Stratification and Indications for Defibrillator Therapy.

Science.gov (United States)

Zorzi, Alessandro; Rigato, Ilaria; Bauce, Barbara; Pilichou, Kalliopi; Basso, Cristina; Thiene, Gaetano; Iliceto, Sabino; Corrado, Domenico

2016-06-01

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically determined disease which predisposes to life-threatening ventricular arrhythmias. The main goal of ARVC therapy is prevention of sudden cardiac death (SCD). Implantable cardioverter defibrillator (ICD) is the most effective therapy for interruption of potentially lethal ventricular tachyarrhythmias. Despite its life-saving potential, ICD implantation is associated with a high rate of complications and significant impact on quality of life. Accurate risk stratification is needed to identify individuals who most benefit from the therapy. While there is general agreement that patients with a history of cardiac arrest or hemodynamically unstable ventricular tachycardia are at high risk of SCD and needs an ICD, indications for primary prevention remain a matter of debate. The article reviews the available scientific evidence and guidelines that may help to stratify the arrhythmic risk of ARVC patients and guide ICD implantation. Other therapeutic strategies, either alternative or additional to ICD, will be also addressed.

Heat-Wave Effects on Oxygen, Nutrients, and Phytoplankton Can Alter Global Warming Potential of Gases Emitted from a Small Shallow Lake.

Science.gov (United States)

Bartosiewicz, Maciej; Laurion, Isabelle; Clayer, François; Maranger, Roxane

2016-06-21

Increasing air temperatures may result in stronger lake stratification, potentially altering nutrient and biogenic gas cycling. We assessed the impact of climate forcing by comparing the influence of stratification on oxygen, nutrients, and global-warming potential (GWP) of greenhouse gases (the sum of CH4, CO2, and N2O in CO2 equivalents) emitted from a shallow productive lake during an average versus a heat-wave year. Strong stratification during the heat wave was accompanied by an algal bloom and chemically enhanced carbon uptake. Solar energy trapped at the surface created a colder, isolated hypolimnion, resulting in lower ebullition and overall lower GWP during the hotter-than-average year. Furthermore, the dominant CH4 emission pathway shifted from ebullition to diffusion, with CH4 being produced at surprisingly high rates from sediments (1.2-4.1 mmol m(-2) d(-1)). Accumulated gases trapped in the hypolimnion during the heat wave resulted in a peak efflux to the atmosphere during fall overturn when 70% of total emissions were released, with littoral zones acting as a hot spot. The impact of climate warming on the GWP of shallow lakes is a more complex interplay of phytoplankton dynamics, emission pathways, thermal structure, and chemical conditions, as well as seasonal and spatial variability, than previously reported.

Ion species stratification within strong shocks in two-ion plasmas

Science.gov (United States)

Keenan, Brett D.; Simakov, Andrei N.; Taitano, William T.; Chacón, Luis

2018-03-01

Strong collisional shocks in multi-ion plasmas are featured in many environments, with Inertial Confinement Fusion (ICF) experiments being one prominent example. Recent work [Keenan et al., Phys. Rev. E 96, 053203 (2017)] answered in detail a number of outstanding questions concerning the kinetic structure of steady-state, planar plasma shocks, e.g., the shock width scaling by the Mach number, M. However, it did not discuss shock-driven ion-species stratification (e.g., relative concentration modification and temperature separation). These are important effects since many recent ICF experiments have evaded explanation by standard, single-fluid, radiation-hydrodynamic (rad-hydro) numerical simulations, and shock-driven fuel stratification likely contributes to this discrepancy. Employing the state-of-the-art Vlasov-Fokker-Planck code, iFP, along with multi-ion hydro simulations and semi-analytics, we quantify the ion stratification by planar shocks with the arbitrary Mach number and the relative species concentration for two-ion plasmas in terms of ion mass and charge ratios. In particular, for strong shocks, we find that the structure of the ion temperature separation has a nearly universal character across ion mass and charge ratios. Additionally, we find that the shock fronts are enriched with the lighter ion species and the enrichment scales as M4 for M ≫ 1.

Effects of momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei

International Nuclear Information System (INIS)

Li Baoan; Das, Champak B.; Das Gupta, Subal; Gale, Charles

2004-01-01

Using an isospin- and momentum-dependent transport model we study effects of the momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei. It is found that symmetry potentials with and without the momentum-dependence but corresponding to the same density-dependent symmetry energy E sym (ρ) lead to significantly different predictions on several E sym (ρ)-sensitive experimental observables especially for energetic nucleons. The momentum- and density-dependence of the symmetry potential have to be determined simultaneously in order to extract the E sym (ρ) accurately. The isospin asymmetry of midrapidity nucleons at high transverse momenta is particularly sensitive to the momentum-dependence of the symmetry potential. It is thus very useful for investigating accurately the equation of state of dense neutron-rich matter

Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Iron and Steel Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Keith Jamison, Caroline Kramer, Sabine Brueske, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. iron and steel manufacturing. The study relies on multiple sources to estimate the energy used in six individual process areas and select subareas, representing 82% of sector-wide energy consumption. Energy savings opportunities for individual processes and subareas are based on technologies currently in use or under development; the potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

Numerical modeling of flows and pollutant dispersion within and above urban street canyons under unstable thermal stratification by large-eddy simulation

Science.gov (United States)

Chan, Ming-Chung; Liu, Chun-Ho

2013-04-01

Recently, with the ever increasing urban areas in developing countries, the problem of air pollution due to vehicular exhaust arouses the concern of different groups of people. Understanding how different factors, such as urban morphology, meteorological conditions and human activities, affect the characteristics of street canyon ventilation, pollutant dispersion above urban areas and pollutant re-entrainment from the shear layer can help us improve air pollution control strategies. Among the factors mentioned above, thermal stratification is a significant one determining the pollutant transport behaviors in certain situation, e.g. when the urban surface is heated by strong solar radiation, which, however, is still not widely explored. The objective of this study is to gain an in-depth understanding of the effects of unstable thermal stratification on the flows and pollutant dispersion within and above urban street canyons through numerical modeling using large-eddy simulation (LES). In this study, LES equipped with one-equation subgrid-scale (SGS) model is employed to model the flows and pollutant dispersion within and above two-dimensional (2D) urban street canyons (flanked by idealized buildings, which are square solid bars in these models) under different intensities of unstable thermal stratifications. Three building-height-to-street-width (aspect) ratios, 0.5, 1 and 2, are included in this study as a representation of different building densities. The prevailing wind flow above the urban canopy is driven by background pressure gradient, which is perpendicular to the street axis, while the condition of unstable thermal stratification is induced by applying a higher uniform temperature on the no-slip urban surface. The relative importance between stratification and background wind is characterized by the Richardson number, with zero value as a neutral case and negative value as an unstable case. The buoyancy force is modeled by Boussinesq approximation and the

Assessment of triton potential energy

International Nuclear Information System (INIS)

Friar, J.L.; Payne, G.L.

1995-01-01

An assessment is made of the dominant features contributing to the triton potential energy, with the objective of understanding qualitatively their origins and sensitivities. Relativistic effects, short-range repulsion, and OPEP dominance are discussed. A determination of the importance of various regions of nucleon-nucleon separation is made numerically. (author)

The prostate cancer risk stratification (ProCaRS) project: Recursive partitioning risk stratification analysis

International Nuclear Information System (INIS)

Rodrigues, George; Lukka, Himu; Warde, Padraig; Brundage, Michael; Souhami, Luis; Crook, Juanita; Cury, Fabio; Catton, Charles; Mok, Gary; Martin, Andre-Guy; Vigneault, Eric; Morris, Jim; Warner, Andrew; Gonzalez Maldonado, Sandra; Pickles, Tom

2013-01-01

Background: The Genitourinary Radiation Oncologists of Canada (GUROC) published a three-group risk stratification (RS) system to assist prostate cancer decision-making in 2001. The objective of this project is to use the ProCaRS database to statistically model the predictive accuracy and clinical utility of a proposed new multi-group RS schema. Methods: The RS analyses utilized the ProCaRS database that consists of 7974 patients from four Canadian institutions. Recursive partitioning analysis (RPA) was utilized to explore the sub-stratification of groups defined by the existing three-group GUROC scheme. 10-fold cross-validated C-indices and the Net Reclassification Index were both used to assess multivariable models and compare the predictive accuracy of existing and proposed RS systems, respectively. Results: The recursive partitioning analysis has suggested that the existing GUROC classification system could be altered to accommodate as many as six separate and statistical unique groups based on differences in BFFS (C-index 0.67 and AUC 0.70). GUROC low-risk patients would be divided into new favorable-low and low-risk groups based on PSA ⩽6 and PSA >6. GUROC intermediate-risk patients can be subclassified into low-intermediate and high-intermediate groups. GUROC high-intermediate-risk is defined as existing GUROC intermediate-risk with PSA >=10 AND either T2b/c disease or T1T2a disease with Gleason 7. GUROC high-risk patients would be subclassified into an additional extreme-risk group (GUROC high-risk AND (positive cores ⩾87.5% OR PSA >30). Conclusions: Proposed RS subcategories have been identified by a RPA of the ProCaRS database

Modeling of condensation, stratification, and mixing phenomena in a pool of water

Energy Technology Data Exchange (ETDEWEB)

Li, H.; Kudinov, P.; Villanueva, W. (Royal Institute of Technology (KTH). Div. of Nuclear Power Safety, Stockholm (Sweden))

2010-12-15

This work pertains to the research program on Containment Thermal-Hydraulics at KTH. The objective is to evaluate and improve performance of methods, which are used to analyze thermal-hydraulics of steam suppression pools in a BWR plant under different abnormal transient and accident conditions. As a passive safety system, the function of steam pressure suppression pools is paramount to the containment performance. In the present work, the focus is on apparently-benign but intricate and potentially risk-significant scenarios in which thermal stratification could significantly impede the pool's pressure suppression capacity. For the case of small flow rates of steam influx, the steam condenses rapidly in the pool and the hot condensate rises in a narrow plume above the steam injection plane and spreads into a thin layer at the pool's free surface. When the steam flow rate increases significantly, momentum introduced by the steam injection and/or periodic expansion and shrink of large steam bubbles due to direct contact condensation can cause breakdown of the stratified layers and lead to mixing of the pool water. Accurate prediction of the pool thermal-hydraulics in such scenarios presents a computational challenge. Lumped-parameter models have no capability to predict temperature distribution of water pool during thermal stratification development. While high-order-accurate CFD (RANS, LES) methods are not practical due to excessive computing power needed to calculate 3D high-Rayleighnumber natural circulation flow in long transients. In the present work, a middleground approach is used, namely CFD-like model of the general purpose thermalhydraulic code GOTHIC. Each cell of 3D GOTHIC grid uses lumped parameter volume type closures for modeling of various heat and mass transfer processes at subgrid scale. We use GOTHIC to simulate POOLEX/PPOOLEX experiment, in order to (a) quantify errors due to GOTHIC's physical models and numerical schemes, and (b

Nuclear reactions induced by high-energy alpha particles

Science.gov (United States)

Shen, B. S. P.

1974-01-01

Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

Cerebral energy metabolism during induced mitochondrial dysfunction

DEFF Research Database (Denmark)

Nielsen, T H; Bindslev, TT; Pedersen, S M

2013-01-01

In patients with traumatic brain injury as well as stroke, impaired cerebral oxidative energy metabolism may be an important factor contributing to the ultimate degree of tissue damage. We hypothesize that mitochondrial dysfunction can be diagnosed bedside by comparing the simultaneous changes...... in brain tissue oxygen tension (PbtO(2)) and cerebral cytoplasmatic redox state. The study describes cerebral energy metabolism during mitochondrial dysfunction induced by sevoflurane in piglets....

Timing of potential and metabolic brain energy

DEFF Research Database (Denmark)

Korf, Jakob; Gramsbergen, Jan Bert

2007-01-01

functions. We introduce the concepts of potential and metabolic brain energy to distinguish trans-membrane gradients of ions or neurotransmitters and the capacity to generate energy from intra- or extra-cerebral substrates, respectively. Higher brain functions, such as memory retrieval, speaking......The temporal relationship between cerebral electro-physiological activities, higher brain functions and brain energy metabolism is reviewed. The duration of action potentials and transmission through glutamate and GABA are most often less than 5 ms. Subjects may perform complex psycho......-physiological tasks within 50 to 200 ms, and perception of conscious experience requires 0.5 to 2 s. Activation of cerebral oxygen consumption starts after at least 100 ms and increases of local blood flow become maximal after about 1 s. Current imaging technologies are unable to detect rapid physiological brain...

Dissociation energies of six NO2 isotopologues by laser induced fluorescence spectroscopy and zero point energy of some triatomic molecules.

Science.gov (United States)

Michalski, G; Jost, R; Sugny, D; Joyeux, M; Thiemens, M

2004-10-15

We have measured the rotationless photodissociation threshold of six isotopologues of NO2 containing 14N, 15N, 16O, and 18O isotopes using laser induced fluorescence detection and jet cooled NO2 (to avoid rotational congestion). For each isotopologue, the spectrum is very dense below the dissociation energy while fluorescence disappears abruptly above it. The six dissociation energies ranged from 25 128.56 cm(-1) for 14N16O2 to 25 171.80 cm(-1) for 15N18O2. The zero point energy for the NO2 isotopologues was determined from experimental vibrational energies, application of the Dunham expansion, and from canonical perturbation theory using several potential energy surfaces. Using the experimentally determined dissociation energies and the calculated zero point energies of the parent NO2 isotopologue and of the NO product(s) we determined that there is a common De = 26 051.17+/-0.70 cm(-1) using the Born-Oppenheimer approximation. The canonical perturbation theory was then used to calculate the zero point energy of all stable isotopologues of SO2, CO2, and O3, which are compared with previous determinations.

Models of the plasma corona formation and stratification of exploding micro-wires

International Nuclear Information System (INIS)

Volkov, N.B.; Sarkisov, G.S.; Struve, K.W.; McDaniel, D.H.

2005-01-01

There are proposed the models pf plasma corona formation and stratification of a gas-plasma core of exploding micro-wire. The opportunity of use for the description of physical processes in a formed plasma corona of an electronic magnetohydrodynamics is generalized in view of change of particle number as a result of evaporation, ionization and a leaving of electrons on a wire surface. Necessity of the account of influence of a hot plasma corona on stratification of a gas-plasma core was grounded [ru

Potential energy surfaces for nucleon exchanging in dinuclear systems

International Nuclear Information System (INIS)

Li Jianfeng; Xu Hushan; Li Wenfei; Zuo Wei; Li Junqing; Wang Nan; Zhao Enguang

2003-01-01

The experimental measurements have provided the evidence that the suppression of fusion cross-section caused by quasi-fission is very important for the synthesis of super-heavy nuclei by heavy ion collisions. The potential energy surface due to the nucleon transfer in the collision process is the driven potential, which governs the nucleon transfer, so that governs the competition between the fusion and quasi-fission. The dinuclear system potential energy surface also gives the information about the optimum projectile-target combination, as well as the optimum excitation energy for the synthesis of super-heavy nuclei by heavy ion collisions

Seed flotation and germination of salt marsh plants: The effects of stratification, salinity, and/or inundation regime

Science.gov (United States)

Elsey-Quirk, T.; Middleton, B.A.; Proffitt, C.E.

2009-01-01

We examined the effects of cold stratification and salinity on seed flotation of eight salt marsh species. Four of the eight species were tested for germination success under different stratification, salinity, and flooding conditions. Species were separated into two groups, four species received wet stratification and four dry stratification and fresh seeds of all species were tested for flotation and germination. Fresh seeds of seven out of eight species had flotation times independent of salinity, six of which had average flotation times of at least 50 d. Seeds of Spartina alterniflora and Spartina patens had the shortest flotation times, averaging 24 and 26 d, respectively. Following wet stratification, the flotation time of S. alterniflora seeds in higher salinity water (15 and 36 ppt) was reduced by over 75% and germination declined by more than 90%. Wet stratification reduced the flotation time of Distichlis spicata seeds in fresh water but increased seed germination from 2 to 16% in a fluctuating inundation regime. Fresh seeds of Iva frutescens and S. alternflora were capable of germination and therefore are non-dormant during dispersal. Fresh seeds of I. frutescens had similar germination to dry stratified seeds ranging 25-30%. Salinity reduced seed germination for all species except for S. alterniflora. A fluctuating inundation regime was important for seed germination of the low marsh species and for germination following cold stratification. The conditions that resulted in seeds sinking faster were similar to the conditions that resulted in higher germination for two of four species. ?? 2009 Elsevier B.V.

Dark energy exponential potential models as curvature quintessence

International Nuclear Information System (INIS)

Capozziello, S; Cardone, V F; Piedipalumbo, E; Rubano, C

2006-01-01

It has been recently shown that, under some general conditions, it is always possible to find a fourth-order gravity theory capable of reproducing the same dynamics as a given dark energy model. Here, we discuss this approach for a dark energy model with a scalar field evolving under the action of an exponential potential. In the absence of matter, such a potential can be recovered from a fourth-order theory via a conformal transformation. Including the matter term, the function f(R) entering the generalized gravity Lagrangian can be reconstructed according to the dark energy model

Numerical simulation of inducing characteristics of high energy electron beam plasma for aerodynamics applications

Science.gov (United States)

Deng, Yongfeng; Jiang, Jian; Han, Xianwei; Tan, Chang; Wei, Jianguo

2017-04-01

The problem of flow active control by low temperature plasma is considered to be one of the most flourishing fields of aerodynamics due to its practical advantages. Compared with other means, the electron beam plasma is a potential flow control method for large scale flow. In this paper, a computational fluid dynamics model coupled with a multi-fluid plasma model is established to investigate the aerodynamic characteristics induced by electron beam plasma. The results demonstrate that the electron beam strongly influences the flow properties, not only in the boundary layers, but also in the main flow. A weak shockwave is induced at the electron beam injection position and develops to the other side of the wind tunnel behind the beam. It brings additional energy into air, and the inducing characteristics are closely related to the beam power and increase nonlinearly with it. The injection angles also influence the flow properties to some extent. Based on this research, we demonstrate that the high energy electron beam air plasma has three attractive advantages in aerodynamic applications, i.e. the high energy density, wide action range and excellent action effect. Due to the rapid development of near space hypersonic vehicles and atmospheric fighters, by optimizing the parameters, the electron beam can be used as an alternative means in aerodynamic steering in these applications.

The potential energy conservation of the Dutch industrial, business and service sector

International Nuclear Information System (INIS)

Van der Werff, R.L.; Opschoor, J.B.

1992-01-01

The database ICARUS has been used as a starting point to estimate the economical potential for energy conservation in different sectors of the Dutch society. ICARUS is based on research on real energy consuming processes and applications in a number of sub-sectors of the Dutch economy. The present energy conservation potential in the Netherlands is based on energy conservation studies in the Netherlands and other countries. For this article the economical efficient energy conservation potentials in 1992 have been investigated for the Dutch sectors, which do not supply energy. The potentials are determined on the basis of the technical energy conservation potentials for the year 2000, according to the database ICARUS. Two methods were used to extract the economic potential from the technical potential: the method of the Net Market Value and the method of the payback period. From the ICARUS analysis it appears that the technical potential for energy conservation is 479 PJ, which is 28.8% of the primary energy consumption of 1664 PJ in 1985. The economic energy conservation potential is 262 PJ for a payback period of less than five years, which is 17% of the 1985 primary energy consumption. Next to the above-mentioned analysis policy-aimed simulations were carried out for three scenarios to determine economical energy conservation potentials. In one scenario doubled energy prices were used in comparison with the 1991 prices. Another scenario uses the Net Market Value method with a 5% discount rate, and the third scenario uses both parameters

Technical and Economic Potential of Distributed Energy Storages for the Integration of Renewable Energy

DEFF Research Database (Denmark)

Sveinbjörnsson, Dadi Þorsteinn; Trier, Daniel; Hansen, Kenneth

Very high penetration of fluctuating renewable energy sources can lead to new challenges in balancing energy supply and demand in future energy systems. This work, carried out as a part of Annex 28 of the IEA ECES programme, addresses this. The aim of the study is to identify which role decentral...... indicate that sector coupling along with an intelligent choice of distributed energy storage technologies can enable the integration of large shares of fluctuating renewable energy in an energy efficient and cost-effective way.......Very high penetration of fluctuating renewable energy sources can lead to new challenges in balancing energy supply and demand in future energy systems. This work, carried out as a part of Annex 28 of the IEA ECES programme, addresses this. The aim of the study is to identify which role...... decentralised energy storages (DES) should play in integrating fluctuating renewable energy sources. The technical and economic potential for DES solutions is quantified using energy system modelling, and it is identified which DES technologies have the largest total (technical and economic) potential. For this...

Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer

Science.gov (United States)

2017-10-01

AWARD NUMBER: W81XWH-16-1-0737 TITLE: Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer PRINCIPAL...AND SUBTITLE 5a. CONTRACT NUMBER Developing a PTEN-ERG Signature to Improve Molecular Risk Stratification in Prostate Cancer 5b. GRANT NUMBER W81XWH...that there exist distinctive molecular correlates of PTEN loss in the context of ETS-negative versus ETS-positive human prostate cancers and that

Methodology for estimating biomass energy potential and its application to Colombia

International Nuclear Information System (INIS)

Gonzalez-Salazar, Miguel Angel; Morini, Mirko; Pinelli, Michele; Spina, Pier Ruggero; Venturini, Mauro; Finkenrath, Matthias; Poganietz, Witold-Roger

2014-01-01

Highlights: • Methodology to estimate the biomass energy potential and its uncertainty at a country level. • Harmonization of approaches and assumptions in existing assessment studies. • The theoretical and technical biomass energy potential in Colombia are estimated in 2010. - Abstract: This paper presents a methodology to estimate the biomass energy potential and its associated uncertainty at a country level when quality and availability of data are limited. The current biomass energy potential in Colombia is assessed following the proposed methodology and results are compared to existing assessment studies. The proposed methodology is a bottom-up resource-focused approach with statistical analysis that uses a Monte Carlo algorithm to stochastically estimate the theoretical and the technical biomass energy potential. The paper also includes a proposed approach to quantify uncertainty combining a probabilistic propagation of uncertainty, a sensitivity analysis and a set of disaggregated sub-models to estimate reliability of predictions and reduce the associated uncertainty. Results predict a theoretical energy potential of 0.744 EJ and a technical potential of 0.059 EJ in 2010, which might account for 1.2% of the annual primary energy production (4.93 EJ)

Mixed convection and stratification phenomena in a heavy liquid metal pool

Energy Technology Data Exchange (ETDEWEB)

Tarantino, Mariano, E-mail: mariano.tarantino@enea.it [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone (Italy); Martelli, Daniele; Barone, Gianluca [Dipartimento di Ingegneria Civile e Industriale, University of Pisa, Largo Lucio Lazzarino, 1-56100 Pisa Italy (Italy); Di Piazza, Ivan [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone (Italy); Forgione, Nicola [Dipartimento di Ingegneria Civile e Industriale, University of Pisa, Largo Lucio Lazzarino, 1-56100 Pisa Italy (Italy)

2015-05-15

Highlights: • Results related to experiments reproducing PLOHS + LOF accident in CIRCE pool facility. • Vertical thermal stratification in large HLM pool. • Transition from forced to natural circulation in HLM pool under DHR conditions. • Heat transfer coefficient measurement in HLM pin bundle. • Nusselt numbers calculations and comparison with correlations. - Abstract: This work deals with an analysis of the first experimental series of tests performed to investigate mixed convection and stratification phenomena in CIRCE HLM large pool. In particular, the tests concern the transition from nominal flow to natural circulation regime, typical of decay heat removal (DHR) regime. To this purpose the CIRCE pool facility has been updated to host a suitable test section in order to reproduce the thermal-hydraulic behaviour of a HLM pool-type reactor. The test section basically consists of an electrical bundle (FPS) made up of 37 pins arranged in a hexagonal wrapped lattice with a pitch diameter ratio of 1.8. Along the FPS active length, three sections were instrumented to monitor the heat transfer coefficient along the bundle as well as the cladding temperatures at different ranks of the sub-channels. This paper reports the experimental data as well as a preliminary analysis and discussion of the results, focusing on the most relevant tests of the campaign, namely Test I (48 h) and Test II (97 h). Temperatures along three sections of the FPS and at inlet and outlet sections of the main components were reported and the Nusselt number in the FPS sub-channels was investigated together with the void fraction in the riser. Concerning the investigation of in-pool thermal stratification phenomena, the temperatures in the whole LBE pool were monitored at different elevations and radial locations. The analysis of experimental data obtained from Tests I and II underline the occurrence of thermal stratification phenomena in the region placed between the outlet sections of

AN INVESTIGATION OF WAVE ENERGY POTENTIAL IN WESTERN BLACK SEA REGION

Directory of Open Access Journals (Sweden)

İlyas UYGUR

2006-01-01

Full Text Available The main energy sources which are natural, clean, environmentally friendly, and renewable are wind power, solar energy, biomass energy, hydro energy, and wave energy. The wave energy has no cost except for the first investment and maintenance. There is also no cost for input energy. Besides these, it has no pollution effect on the environment, it is cheap and there is a huge potential all around the world. Wave energy is a good opportunity to solve the energy problem for Turkey which is surrounded by seas. Concerning all these facts, it has been conducted some studies which included five years of observation in the Western Black Sea Region (Akçakoca. The wave energy potential has also been calculated. From this sutdy results, it can be concluded that the wave energy potential of this region is inefficient. It is believed that by the improvement of the new energy converter devices in future, this low potential can be used more efficiently and as a result this study might be used as a basis for the future researches.

Numerical Investigation on Effects of Assigned EGR Stratification on a Heavy Duty Diesel Engine with Two-Stage Fuel Injection

Directory of Open Access Journals (Sweden)

Zhaojie Shen

2018-02-01

Full Text Available External exhaust gas recirculation (EGR stratification in diesel engines contributes to reduction of toxic emissions. Weak EGR stratification lies in that strong turbulence and mixing between EGR and intake air by current introduction strategies of EGR. For understanding of ideal EGR stratification combustion, EGR was assigned radically at −30 °CA after top dead center (ATDC to organize strong EGR stratification using computational fluid dynamics (CFD. The effects of assigned EGR stratification on diesel performance and emissions are discussed in this paper. Although nitric oxides (NOx and soot emissions are both reduced by means of EGR stratification compared to uniform EGR, the trade-off between NOx and soot still exists under the condition of arranged EGR stratification with different fuel injection strategies. A deterioration of soot emissions was observed when the interval between main and post fuel injection increased, while NO emissions increased first then reduced. The case with a 4 °CA interval between main and post fuel injection is suitable for acceptable NO and soot emissions. Starting the main fuel injection too early and too late is not acceptable, which results in high NO emissions and high soot emissions respectively. The start of the main fuel injection −10 °CA ATDC is suitable.

Impact of Weather and Occupancy on Energy Flexibility Potential of a Low-energy Building

DEFF Research Database (Denmark)

Zilio, Emanuele; Foteinaki, Kyriaki; Gianniou, Panagiota

The introduction of renewable energy sources in the energy market leads to instability of the energy system itself; therefore, new solutions to increase its flexibility will become more common in the coming years. In this context the implementation of energy flexibility in buildings is evaluated...... solar radiation and the outdoor temperature appeared to have the larger impact on the thermal flexibility of the building. Specifically, the energy flexibility potential of the examined apartment can ensure its thermal autonomy up to 200 h in a typical sunny winter day......., using heat storage in the building mass. This study focuses on the influence of weather conditions and internal gains on the energy flexibility potential of a nearly-zero-energy building in Denmark. A specific six hours heating program is used to reach the scope. The main findings showed that the direct...

Tidal deformations of neutron stars: The role of stratification and elasticity

International Nuclear Information System (INIS)

Penner, A. J.; Andersson, N.; Hawke, I.; Jones, D. I.; Samuelsson, L.

2011-01-01

We discuss the response of neutron stars to the tidal interaction in a compact binary system, as encoded in the Love number associated with the induced deformation. This problem is of interest for gravitational-wave astronomy as there may be a detectable imprint on the signal from the late stages of binary coalescence. Previous work has focused on simple barotropic neutron star models, providing an understanding of the role of the stellar compactness and overall density profile. We add realism to the discussion by developing the framework required to model stars with varying composition and an elastic crust. These effects are not expected to be significant for the next generation of detectors, but it is nevertheless useful to be able to quantify them. Our results show that (perhaps surprisingly) internal stratification has no impact whatsoever on the Love number. We also show that crust elasticity provides a (predictably) small correction to existing models.

Effects of cold stratification, sulphuric acid, submersion in hot and ...

African Journals Online (AJOL)

Effects of cold stratification, sulphuric acid, submersion in hot and tap water pretreatments in the greenhouse and open field conditions on germination of bladder-Senna ( Colutea armena Boiss. and Huet.) seeds.

Potential future waste-to-energy systems

OpenAIRE

Thorin, Eva; Guziana, Bozena; Song, Han; Jääskeläinen, Ari; Szpadt, Ryszard; Vasilic, Dejan; Ahrens, Thorsten; Anne, Olga; Lõõnik, Jaan

2012-01-01

This report discusses potential future systems for waste-to-energy production in the Baltic Sea Region, and especially for the project REMOWE partner regions, the County of Västmanland in Sweden, Northern Savo in Finland, Lower Silesia in Poland, western part of Lithuania and Estonia. The waste-to-energy systems planned for in the partner regions are combustion of municipal solid waste (MSW) and solid recovered fuels from household and industry as well as anaerobic digestion of sewage sludge ...

Reevaluation of Turkey's hydropower potential and electric energy demand

International Nuclear Information System (INIS)

Yueksek, Omer

2008-01-01

This paper deals with Turkey's hydropower potential and its long-term electric energy demand predictions. In the paper, at first, Turkey's energy sources are briefly reviewed. Then, hydropower potential is analyzed and it has been concluded that Turkey's annual economically feasible hydropower potential is about 188 TWh, nearly 47% greater than the previous estimation figures of 128 TWh. A review on previous prediction models for Turkey's long-term electric energy demand is presented. In order to predict the future demand, new increment ratio scenarios, which depend on both observed data and future predictions of population, energy consumption per capita and total energy consumption, are developed. The results of 11 prediction models are compared and analyzed. It is concluded that Turkey's annual electric energy demand predictions in 2010, 2015 and 2020 vary between 222 and 242 (average 233) TWh; 302 and 356 (average 334) TWh; and 440 and 514 (average 476) TWh, respectively. A discussion on the role of hydropower in meeting long-term demand is also included in the paper and it has been predicted that hydropower can meet 25-35% of Turkey's electric energy demand in 2020

Chronic lead exposure induces cochlear oxidative stress and potentiates noise-induced hearing loss.

Science.gov (United States)

Jamesdaniel, Samson; Rosati, Rita; Westrick, Judy; Ruden, Douglas M

2018-08-01

Acquired hearing loss is caused by complex interactions of multiple environmental risk factors, such as elevated levels of lead and noise, which are prevalent in urban communities. This study delineates the mechanism underlying lead-induced auditory dysfunction and its potential interaction with noise exposure. Young-adult C57BL/6 mice were exposed to: 1) control conditions; 2) 2 mM lead acetate in drinking water for 28 days; 3) 90 dB broadband noise 2 h/day for two weeks; and 4) both lead and noise. Blood lead levels were measured by inductively coupled plasma mass spectrometry analysis (ICP-MS) lead-induced cochlear oxidative stress signaling was assessed using targeted gene arrays, and the hearing thresholds were assessed by recording auditory brainstem responses. Chronic lead exposure downregulated cochlear Sod1, Gpx1, and Gstk1, which encode critical antioxidant enzymes, and upregulated ApoE, Hspa1a, Ercc2, Prnp, Ccl5, and Sqstm1, which are indicative of cellular apoptosis. Isolated exposure to lead or noise induced 8-12 dB and 11-25 dB shifts in hearing thresholds, respectively. Combined exposure induced 18-30 dB shifts, which was significantly higher than that observed with isolated exposures. This study suggests that chronic exposure to lead induces cochlear oxidative stress and potentiates noise-induced hearing impairment, possibly through parallel pathways. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Integrated inventory-based carbon accounting for energy-induced emissions in Chongming eco-island of Shanghai, China

International Nuclear Information System (INIS)

Li Qingqing; Guo Ru; Li Fengting; Xia Bingbin

2012-01-01

The majority of the total carbon emissions in China are energy induced. A clear understanding of energy-induced carbon emissions is therefore necessary for local communities to develop a better carbon emissions management system. We develop an integrated inventory method for energy-induced carbon emissions accounting in local Chinese communities. The method combines scope and sectoral analyses on the basis of local statistical features. As an outcome four core findings are presented: (1) From 2000 to 2009, the energy-induced carbon emissions of Chongming rapidly increased from 1.75 to 4.90 million tons, with the annual growth rate of 12.12%. (2) Emissions from manufacturing, construction, and household sectors accounted for 84.44%; manufacturing is the biggest emitting sector. (3) Carbon emissions from imported electricity reached a historic high of 22.51% in 2009, indicating the necessity of taking the imported carbon emissions into consideration. (4) In 2008, the per capita carbon emissions of Chongming were lower than that of the United States and Shanghai, but higher than that of the global average. Three strategic approaches are proposed: to optimize industrial structure and improve efficiency, reinforce carbon management for the household sector, and enhance carbon statistics. - Highlights: ► The use of natural gas in the large-sized industrial and commercial sectors is shown. ► This study estimates the market potential and characterizes the energy consumption. ► It makes a selection of technological alternatives for the use of natural gas. ► The residual oil and diesel consumption decline over time by the natural gas use. ► In 2017, the cogeneration could provide 7.7% of total electricity demand in Peru.

Redox stratification of an ancient lake in Gale crater, Mars.

Science.gov (United States)

Hurowitz, J A; Grotzinger, J P; Fischer, W W; McLennan, S M; Milliken, R E; Stein, N; Vasavada, A R; Blake, D F; Dehouck, E; Eigenbrode, J L; Fairén, A G; Frydenvang, J; Gellert, R; Grant, J A; Gupta, S; Herkenhoff, K E; Ming, D W; Rampe, E B; Schmidt, M E; Siebach, K L; Stack-Morgan, K; Sumner, D Y; Wiens, R C

2017-06-02

In 2012, NASA's Curiosity rover landed on Mars to assess its potential as a habitat for past life and investigate the paleoclimate record preserved by sedimentary rocks inside the ~150-kilometer-diameter Gale impact crater. Geological reconstructions from Curiosity rover data have revealed an ancient, habitable lake environment fed by rivers draining into the crater. We synthesize geochemical and mineralogical data from lake-bed mudstones collected during the first 1300 martian solar days of rover operations in Gale. We present evidence for lake redox stratification, established by depth-dependent variations in atmospheric oxidant and dissolved-solute concentrations. Paleoclimate proxy data indicate that a transition from colder to warmer climate conditions is preserved in the stratigraphy. Finally, a late phase of geochemical modification by saline fluids is recognized. Copyright © 2017, American Association for the Advancement of Science.

Understanding the Effect of Stratification on Vertical and Temporal Heterogenieties of Cyanobacteria Blooms in Lakes Using a Long Term in-situ Monitoring Station

Science.gov (United States)

Wilkinson, A.; Guala, M.; Hondzo, M.

2017-12-01

Harmful Algal Blooms (HAB) are made up of potentially toxic freshwater microorganisms called cyanobacteria, because of this they are a ecological and public health hazard. The occurrences of toxic HAB are unpredictable and highly spatially and temporary variable in freshwater ecosystems. To study the abiotic drivers for toxic HAB, a floating research station has been deployed in a hyper-eutrophic lake in Madison Lake, Minnesota, from June-October 2016. This research station provides full depth water quality (hourly) and meteorological monitoring (5 minutes). Water quality monitoring is performed by an autonomously traversed water quality sonde that provides chemical, physical and biological measurements; including phycocyanin, a photosynthetic pigment distinct to cyanobacteria. A bloom of cyanobacteria recorded in the epiliminion in mid-July was driven by prolonged strong thermal stratification in the water column, high surface water temperatures and high phosphate concentrations in the epiliminion. The high biovolume (BV) persisted until late September and was sustained below the surface after stratification weakened, when the thermocline did not confine cyanobacteria-rich layers any more, and cyanobacteria vertical heterogeneities decayed in the water column. High correlations among BV stratification, surface water temperature, and stratification stability informed the development of a quantitative relationship to determine how BV heterogeneities vary with thermal structure in the water column. The BV heterogeneity decreased with thermal stratification stability and surface water temperature, and the dynamic lake stability described by the Lake Number. Finally the location of maximum BV accumulation showed diurnal patterns ie. BV peaks were observed at 1 m depth during the day and deeper layers during the night, which followed patterns in light penetration and thermocline depth. These findings capture cyanobacteria vertical and temporal heterogeneities on a on

Ternary-fragmentation-driving potential energies of 252Cf

Science.gov (United States)

Karthikraj, C.; Ren, Zhongzhou

2017-12-01

Within the framework of a simple macroscopic model, the ternary-fragmentation-driving potential energies of 252Cf are studied. In this work, all possible ternary-fragment combinations of 252Cf are generated by the use of atomic mass evaluation-2016 (AME2016) data and these combinations are minimized by using a two-dimensional minimization approach. This minimization process can be done in two ways: (i) with respect to proton numbers (Z1, Z2, Z3) and (ii) with respect to neutron numbers (N1, N2, N3) of the ternary fragments. In this paper, the driving potential energies for the ternary breakup of 252Cf are presented for both the spherical and deformed as well as the proton-minimized and neutron-minimized ternary fragments. From the proton-minimized spherical ternary fragments, we have obtained different possible ternary configurations with a minimum driving potential, in particular, the experimental expectation of Sn + Ni + Ca ternary fragmentation. However, the neutron-minimized ternary fragments exhibit a driving potential minimum in the true-ternary-fission (TTF) region as well. Further, the Q -value energy systematics of the neutron-minimized ternary fragments show larger values for the TTF fragments. From this, we have concluded that the TTF region fragments with the least driving potential and high Q values have a strong possibility in the ternary fragmentation of 252Cf. Further, the role of ground-state deformations (β2, β3, β4, and β6) in the ternary breakup of 252Cf is also studied. The deformed ternary fragmentation, which involves Z3=12 -19 fragments, possesses the driving potential minimum due to the larger oblate deformations. We also found that the ground-state deformations, particularly β2, strongly influence the driving potential energies and play a major role in determining the most probable fragment combinations in the ternary breakup of 252Cf.

Wave energy potential in Galicia (NW Spain)

Energy Technology Data Exchange (ETDEWEB)

Iglesias, G.; Lopez, M.; Carballo, R.; Castro, A. [University of Santiago de Compostela, Hydraulic Engineering, E.P.S., Campus Universitario s/n, 27002 Lugo (Spain); Fraguela, J.A. [University of A Coruna, E.P.S., Campus de Esteiro s/n, Ferrol (Spain); Frigaard, P. [University of Aalborg, Sohngaardsholmsvej 57, DK 9000 (Denmark)

2009-11-15

Wave power presents significant advantages with regard to other CO{sub 2}-free energy sources, among which the predictability, high load factor and low visual and environmental impact stand out. Galicia, facing the Atlantic on the north-western corner of the Iberian Peninsula, is subjected to a very harsh wave climate; in this work its potential for energy production is assessed based on three-hourly data from a third generation ocean wave model (WAM) covering the period 1996-2005. Taking into account the results of this assessment along with other relevant considerations such as the location of ports, navigation routes, and fishing and aquaculture zones, an area is selected for wave energy exploitation. The transformation of the offshore wave field as it propagates into this area is computed by means of a nearshore wave model (SWAN) in order to select the optimum locations for a wave farm. Two zones emerge as those with the highest potential for wave energy exploitation. The large modifications in the available wave power resulting from relatively small changes of position are made apparent in the process. (author)

Analysis on Potential of Electric Energy Market based on Large Industrial Consumer

Science.gov (United States)

Lin, Jingyi; Zhu, Xinzhi; Yang, Shuo; Xia, Huaijian; Yang, Di; Li, Hao; Lin, Haiying

2018-01-01

The implementation of electric energy substitution by enterprises plays an important role in promoting the development of energy conservation and emission reduction in china. In order to explore alternative energy potential of industrial enterprises, to simulate and analyze the process of industrial enterprises, identify high energy consumption process and equipment, give priority to alternative energy technologies, and determine the enterprise electric energy substitution potential predictive value, this paper constructs the evaluation model of the influence factors of the electric energy substitution potential of industrial enterprises, and uses the combined weight method to determine the weight value of the evaluation factors to calculate the target value of the electric energy substitution potential. Taking the iron and steel industry as an example, this method is used to excavate the potential. The results show that the method can effectively tap the potential of the electric power industry

The Social Stratification of the German VET System

Science.gov (United States)

Protsch, Paula; Solga, Heike

2016-01-01

Germany is widely known for its vocational education and training (VET) system and its dual apprenticeship system in particular. What is often overlooked, however, is the vertical stratification within the German VET system. This is the focus of this study. Our analysis shows that the VET system, like the German school system, is highly…

Eigensolutions, Shannon entropy and information energy for modified Tietz-Hua potential

Science.gov (United States)

Onate, C. A.; Onyeaju, M. C.; Ituen, E. E.; Ikot, A. N.; Ebomwonyi, O.; Okoro, J. O.; Dopamu, K. O.

2018-04-01

The Tietz-Hua potential is modified by the inclusion of De ( {{Ch - 1}/{1 - C_{h e^{{ - bh ( {r - re } )}} }}} )be^{{ - bh ( {r - re } )}} term to the Tietz-Hua potential model since a potential of such type is very good in the description and vibrational energy levels for diatomic molecules. The energy eigenvalues and the corresponding eigenfunctions are explicitly obtained using the methodology of parametric Nikiforov-Uvarov. By putting the potential parameter b = 0, in the modified Tietz-Hua potential quickly reduces to the Tietz-Hua potential. To show more applications of our work, we have computed the Shannon entropy and Information energy under the modified Tietz-Hua potential. However, the computation of the Shannon entropy and Information energy is an extension of the work of Falaye et al., who computed only the Fisher information under Tietz-Hua potential.

Potential energy center site investigations

International Nuclear Information System (INIS)

Savage, W.F.

1977-01-01

Past studies by the AEC, NRC, NSF and others have indicated that energy centers have certain advantages over dispersed siting. There is the need, however, to investigate such areas as possible weather modifications due to major heat releases, possible changes in Federal/state/local laws and institutional arrangements to facilitate implementation of energy centers, and to assess methods of easing social and economic pressures on a surrounding community due to center construction. All of these areas are under study by ERDA, but there remains the major requirement for the study of a potential site to yield a true assessment of the energy center concept. In this regard the Division of Nuclear Research and Applications of ERDA is supporting studies by the Southern and Western Interstate Nuclear Boards to establish state and utility interest in the concept and to carry out screening studies of possible sites. After selection of a final site for center study , an analysis will be made of the center including technical areas such as heat dissipation methods, water resource management, transmission methods, construction methods and schedules, co-located fuel cycle facilities, possible mix of reactor types, etc. Additionally, studies of safeguards, the interaction of all effected entities in the siting, construction, licensing and regulation of a center, labor force considerations in terms of local impact, social and economic changes, and financing of a center will be conducted. It is estimated that the potential site study will require approximately two years

Induced innovation, energy prices, and the environment

Science.gov (United States)

Popp, David Clifford

The process of developing new technologies is a central question for economic theory as well as for public policy in many areas. For example, the development of cleaner, more efficient energy technologies will play an important role in reducing the threat of global warming. To study how technology evolves over time, this dissertation uses patent data on energy innovations from 1970 to 1991 to examine the impact of energy prices on energy-efficient innovations. Before this can be done, however, information on supply-side factors which influence innovation is also needed. In the case of innovation, supply-side factors are the usefulness of the existing base of scientific knowledge. Patent citations are used for this purpose. Subsequent citations to patents granted each year since 1970 are used to show that the returns to research and development (R&D) fall over time for most of the technologies studied. These estimates are then combined with data on demand-side factors, such as energy prices, to estimate a model of induced innovation in energy technologies. Both energy prices and the supply of knowledge are found to have strongly significant positive effects on innovation. Next, the Yale Technology Concordance (YTC), which maps patents to the industries in which they are used, is employed to construct a stock of energy-related knowledge for 14 energy intensive industries. The effect of changes in this stock on energy consumption in these industries is estimated. On average, the present value of energy savings resulting from a new patent is eight million dollars, with the maximum savings coming about five years after the initial patent application. Finally, the results of each regression are combined to simulate the impact of a ten percent energy tax. Initially, simple factor substitution due to the price change has the largest effect. However, because of the cumulative nature of R&D, induced innovation has a much larger effect than factor substitution in the long run

Evaluation and verification of thermal stratification models for was

African Journals Online (AJOL)

USER

prediction of the condition of thermal stratification in WSPs under different hydraulic conditions and ... off coefficient. The models are verified with data collected from the full scale waste .... comparing two mathematical models based ..... 2 Comparison of measured and predicted effluent coliform bacteria (N) againsty depth.

The 1995 Georges Bank Stratification Study and Moored Array Measurements

National Research Council Canada - National Science Library

Alessi, C

2001-01-01

.... GLOBEC Northwest Atlantic/Georges Bank field program. The GBSS was designed to investigate the physical processes which control the seasonal development of stratification along the southern flank of Georges Bank during spring and summer...

Alcohol-Induced Impairment of Balance is Antagonized by Energy Drinks.

Science.gov (United States)

Marczinski, Cecile A; Fillmore, Mark T; Stamates, Amy L; Maloney, Sarah F

2018-01-01

The acute administration of alcohol reliably impairs balance and motor coordination. While it is common for consumers to ingest alcohol with other stimulant drugs (e.g., caffeine, nicotine), little is known whether prototypical alcohol-induced balance impairments are altered by stimulant drugs. The purpose of this study was to examine whether the coadministration of a high-caffeine energy drink with alcohol can antagonize expected alcohol-induced increases in body sway. Sixteen social drinkers (of equal gender) participated in 4 separate double-blind dose administration sessions that involved consumption of alcohol and energy drinks, alone and in combination. Following dose administration, participants completed automated assessments of balance stability (both eyes open and eyes closed) measured using the Biosway Portable Balance System. Participants completed several subjective measures including self-reported ratings of sedation, stimulation, fatigue, and impairment. Blood pressure and pulse rate were recorded repeatedly. The acute administration of alcohol increased body sway, and the coadministration of energy drinks antagonized this impairment. When participants closed their eyes, alcohol-induced body sway was similar whether or not energy drinks were ingested. While alcohol administration increased ratings of sedation and fatigue, energy drink administration increased ratings of stimulation and reduced ratings of fatigue. Modest increases in systolic and diastolic blood pressure following energy drink administration were also observed. Visual assessment of balance impairment is frequently used to indicate that an individual has consumed too much alcohol (e.g., as part of police-standardized field sobriety testing or by a bartender assessing when someone should no longer be served more alcohol). The current findings suggest that energy drinks can antagonize alcohol-induced increases in body sway, indicating that future work is needed to determine whether this

Energy Savings Potential and Research & Development Opportunities for Commercial Refrigeration

Energy Technology Data Exchange (ETDEWEB)

none,

2009-09-01

This study documents the energy consumption of commercial refrigeration equipment (CRE) in the U.S. and evaluated the energy savings potential of various technologies and energy efficiency measures that could be applied to such equipment. The study provided an overview of CRE applications, assessed the energy-savings potential of CRE in the U.S., outline key barriers to adoption of energy-savings technologies, and recommended opportunities for advanced energy saving technology research. The study was modeled after an earlier 1996 report by Arthur D. Little, Inc., and updated key information, examined more equipment types, and outlined long-term research and development opportunities.

Evolution of South Atlantic density and chemical stratification across the last deglaciation.

Science.gov (United States)

Roberts, Jenny; Gottschalk, Julia; Skinner, Luke C; Peck, Victoria L; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; Vázquez Riveiros, Natalia; Hodell, David A

2016-01-19

Explanations of the glacial-interglacial variations in atmospheric pCO2 invoke a significant role for the deep ocean in the storage of CO2. Deep-ocean density stratification has been proposed as a mechanism to promote the storage of CO2 in the deep ocean during glacial times. A wealth of proxy data supports the presence of a "chemical divide" between intermediate and deep water in the glacial Atlantic Ocean, which indirectly points to an increase in deep-ocean density stratification. However, direct observational evidence of changes in the primary controls of ocean density stratification, i.e., temperature and salinity, remain scarce. Here, we use Mg/Ca-derived seawater temperature and salinity estimates determined from temperature-corrected δ(18)O measurements on the benthic foraminifer Uvigerina spp. from deep and intermediate water-depth marine sediment cores to reconstruct the changes in density of sub-Antarctic South Atlantic water masses over the last deglaciation (i.e., 22-2 ka before present). We find that a major breakdown in the physical density stratification significantly lags the breakdown of the deep-intermediate chemical divide, as indicated by the chemical tracers of benthic foraminifer δ(13)C and foraminifer/coral (14)C. Our results indicate that chemical destratification likely resulted in the first rise in atmospheric pCO2, whereas the density destratification of the deep South Atlantic lags the second rise in atmospheric pCO2 during the late deglacial period. Our findings emphasize that the physical and chemical destratification of the ocean are not as tightly coupled as generally assumed.

Numerical analysis on hydrogen stratification and post-inerting of hydrogen risk

International Nuclear Information System (INIS)

Peng, Cheng; Tong, Lili; Cao, Xuewu

2016-01-01

Highlights: • A three-dimensional computational model was built and the applicability was discussed. • The formation of helium stratification was further studied. • Three influencing factors on the post-inerting of hydrogen risk were analyzed. - Abstract: In the case of severe accidents, the risk of hydrogen explosion threatens the integrity of the nuclear reactor containment. According to nuclear regulations, hydrogen control is required to ensure the safe operation of the nuclear reactor. In this study, the method of Computational Fluid Dynamics (CFD) has been applied to analyze process of hydrogen stratification and the post-inerting of hydrogen risk in the Large-Scale Gas Mixing Facility. A three-dimensional computational model was built and the applicability of different turbulence models was discussed. The result shows that the helium concentration calculated by the standard k–ε turbulence model is closest to the experiment data. Through analyzing the formation of helium stratification at different injection velocities, it is found that when the injection mass flow is constant and the injection velocity of helium increases, the mixture of helium and air is enhanced while there is rarely influence on the formation of helium stratification. In addition, the influences of mass flow rate, injection location and direction and inert gas on the post-inerting of hydrogen risk have been analyzed and the results are as follows: with the increasing of mass flow rate, the mitigation effect of nitrogen on hydrogen risk will be further improved; there is an obvious local difference between the mitigation effects of nitrogen on hydrogen risk in different injection directions and locations; when the inert gas is injected at the same mass flow rate, the mitigation effect of steam on hydrogen risk is better than that of nitrogen. This study can provide technical support for the mitigation of hydrogen risk in the small LWR containment.

Warm Body Temperature Facilitates Energy Efficient Cortical Action Potentials

Science.gov (United States)

Yu, Yuguo; Hill, Adam P.; McCormick, David A.

2012-01-01

The energy efficiency of neural signal transmission is important not only as a limiting factor in brain architecture, but it also influences the interpretation of functional brain imaging signals. Action potential generation in mammalian, versus invertebrate, axons is remarkably energy efficient. Here we demonstrate that this increase in energy efficiency is due largely to a warmer body temperature. Increases in temperature result in an exponential increase in energy efficiency for single action potentials by increasing the rate of Na+ channel inactivation, resulting in a marked reduction in overlap of the inward Na+, and outward K+, currents and a shortening of action potential duration. This increase in single spike efficiency is, however, counterbalanced by a temperature-dependent decrease in the amplitude and duration of the spike afterhyperpolarization, resulting in a nonlinear increase in the spike firing rate, particularly at temperatures above approximately 35°C. Interestingly, the total energy cost, as measured by the multiplication of total Na+ entry per spike and average firing rate in response to a constant input, reaches a global minimum between 37–42°C. Our results indicate that increases in temperature result in an unexpected increase in energy efficiency, especially near normal body temperature, thus allowing the brain to utilize an energy efficient neural code. PMID:22511855

Warm body temperature facilitates energy efficient cortical action potentials.

Directory of Open Access Journals (Sweden)

Yuguo Yu

Full Text Available The energy efficiency of neural signal transmission is important not only as a limiting factor in brain architecture, but it also influences the interpretation of functional brain imaging signals. Action potential generation in mammalian, versus invertebrate, axons is remarkably energy efficient. Here we demonstrate that this increase in energy efficiency is due largely to a warmer body temperature. Increases in temperature result in an exponential increase in energy efficiency for single action potentials by increasing the rate of Na(+ channel inactivation, resulting in a marked reduction in overlap of the inward Na(+, and outward K(+, currents and a shortening of action potential duration. This increase in single spike efficiency is, however, counterbalanced by a temperature-dependent decrease in the amplitude and duration of the spike afterhyperpolarization, resulting in a nonlinear increase in the spike firing rate, particularly at temperatures above approximately 35°C. Interestingly, the total energy cost, as measured by the multiplication of total Na(+ entry per spike and average firing rate in response to a constant input, reaches a global minimum between 37-42°C. Our results indicate that increases in temperature result in an unexpected increase in energy efficiency, especially near normal body temperature, thus allowing the brain to utilize an energy efficient neural code.

Theoretical potential and utilization of renewable energy in Afghanistan

Directory of Open Access Journals (Sweden)

Gul Ahmad Ludin

2016-12-01

Full Text Available Nowadays, renewable energy is gaining more attention than other resources for electricity generation in the world. For Afghanistan that has limited domestic production of electric power and is more dependent on the unstable imported power from neighboring countries which pave the way to raise the cost of energy and increased different technical and economic problems. The employment of renewable energy would not only contribute to the independence of energy supply but also can achieve the socio-economic benefits for the country which is trying to rebuild its energy sector with a focus on sustainable energy for its population. From a theoretical point of view, there is a considerable potential of renewable energies such as solar energy, wind power, hydropower, biomass and geothermal energy available in the country. However, despite the presence of widespread non-agricultural and non-residential lands, these resources have not been deployed efficiently. This paper assesses the theoretical potential of the aforementioned types of renewable energies in the country. The study indicates that deployment of renewable energies can not only supplement the power demand but also will create other opportunities and will enable a sustainable energy base in Afghanistan.

Energy input and dissipation in a temperate lake during the spring transition

Science.gov (United States)

Woolway, R. Iestyn; Simpson, John H.

2017-08-01

ADCP and temperature chain measurements have been used to estimate the rate of energy input by wind stress to the water surface in the south basin of Windermere. The energy input from the atmosphere was found to increase markedly as the lake stratified in spring. The efficiency of energy transfer ( Eff), defined as the ratio of the rate of working in near-surface waters ( RW) to that above the lake surface ( P 10), increased from ˜0.0013 in vertically homogenous conditions to ˜0.0064 in the first 40 days of the stratified regime. A maximum value of Eff˜0.01 was observed when, with increasing stratification, the first mode internal seiche period decreased to match the diurnal wind period of 24 h. The increase in energy input, following the onset of stratification was reflected in enhancement of the mean depth-varying kinetic energy without a corresponding increase in wind forcing. Parallel estimates of energy dissipation in the bottom boundary layer, based on determination of the structure function show that it accounts for ˜15% of RW in stratified conditions. The evolution of stratification in the lake conforms to a heating stirring model which indicates that mixing accounts for ˜21% of RW. Taken together, these estimates of key energetic parameters point the way to the development of full energy budgets for lakes and shallow seas.

Segmented Poincaré plot analysis for risk stratification in patients with dilated cardiomyopathy.

Science.gov (United States)

Voss, A; Fischer, C; Schroeder, R; Figulla, H R; Goernig, M

2010-01-01

The prognostic value of heart rate variability in patients with dilated cardiomyopathy (DCM) is limited and does not contribute to risk stratification although the dynamics of ventricular repolarization differs considerably between DCM patients and healthy subjects. Neither linear nor nonlinear methods of heart rate variability analysis could discriminate between patients at high and low risk for sudden cardiac death. The aim of this study was to analyze the suitability of the new developed segmented Poincaré plot analysis (SPPA) to enhance risk stratification in DCM. In contrast to the usual applied Poincaré plot analysis the SPPA retains nonlinear features from investigated beat-to-beat interval time series. Main features of SPPA are the rotation of cloud of points and their succeeded variability depended segmentation. Significant row and column probabilities were calculated from the segments and led to discrimination (up to pplot analysis of heart rate variability was able to contribute to risk stratification in patients suffering from DCM.

Inducing Strong Density Modulation with Small Energy Dispersion in Particle Beams and the Harmonic Amplifier Free Electron Laser

CERN Document Server

McNeil, Brian W J; Robb, Gordon

2005-01-01

We present a possible method of inducing a periodic density modulation in a particle beam with little increase in the energy dispersion of the particles. The flow of particles in phase space does not obey Liouville's Theorem. The method relies upon the Kuramoto-like model of collective synchronism found in free electron generators of radiation, such as Cyclotron Resonance Masers and the Free Electron Laser. For the case of an FEL interaction, electrons initially begin to bunch and emit radiation energy with a correlated energy dispersion which is periodic with the FEL ponderomotive potential. The relative phase between potential and particles is then changed by approximately 180 degrees. The particles continue to bunch, however, there is now a correlated re-absorption of energy from the field. We show that, by repeating this relative phase change many times, a significant density modulation of the particles may be achieved with only relatively small energy dispersion. A similar method of repeated relative ele...

Estimating energy conservation potential in China's commercial sector

International Nuclear Information System (INIS)

Lin, Boqiang; Wang, Ailun

2015-01-01

With low energy intensity and great potential for growth, the commercial sector has become one of the key sectors for energy conservation and emission reduction in the context of China's rapid urbanization process. Based on the EIA (Energy Information Administration) statistical methods, this paper calculates the energy consumption of China's commercial sector from 1981 to 2012, specifies the determinants of commercial energy demand, forecasts future energy consumption and estimates the energy conservation potentials using the Johansen co-integration methodology. The results indicate: (i) GDP (Gross Domestic Product) and urbanization have positive effects on the energy consumption of the commercial sector while labor productivity and energy price contribute to reduction in the sector's energy consumption. (ii) Under the basic scenario, energy consumption of the commercial sector will be 317.34 and 469.84 Mtce (million tons of coal equivalent) in 2015 and 2020 respectively. (iii) Under the moderate and advanced scenario, about 187.00 and 531.45 Mtce respectively of the energy consumption of the commercial sector can be conserved from 2013 to 2020. The findings have important implications for policy-makers to enact energy-saving policies. - Highlights: • Calculation of China's commercial energy consumption and saving potential. • Co-integration model is applied to estimate commercial energy efficiency. • Decomposition of driving forces of energy consumption. • Future policies for commercial energy efficiency are discussed

Multi-Layered Stratification in the Baltic Sea: Insight from a Modeling Study with Reference to Environmental Conditions

Directory of Open Access Journals (Sweden)

Bijan Dargahi

2017-01-01

Full Text Available The hydrodynamic and transport characteristics of the Baltic Sea in the period 2000–2009 were studied using a fully calibrated and validated 3D hydrodynamic model with a horizontal resolution of 4.8 km. This study provided new insight into the type and dynamics of vertical structure in the Baltic Sea, not considered in previous studies. Thermal and salinity stratification are both addressed, with a focus on the structural properties of the layers. The detection of cooler regions (dicothermal within the layer structure is an important finding. The detailed investigation of thermal stratification for a 10-year period (i.e., 2000–2009 revealed some new features. A multilayered structure that contains several thermocline and dicothermal layers was identified from this study. Statistical analysis of the simulation results made it possible to derive the mean thermal stratification properties, expressed as mean temperatures and the normalized layer thicknesses. The three-layered model proposed by previous investigators appears to be valid only during the winter periods; for other periods, a multi-layered structure with more than five layers has been identified during this investigation. This study provides detailed insight into thermal and salinity stratification in the Baltic Sea during a recent decade that can be used as a basis for diverse environmental assessments. It extends previous studies on stratification in the Baltic Sea regarding both the extent and the nature of stratification.

Study of the potential of wave energy in Malaysia

Science.gov (United States)

Tan, Wan Ching; Chan, Keng Wai; Ooi, Heivin

2017-07-01

Renewable energy is generally defined as energy harnessed from resources which are naturally replenished. It is an alternative to the current conventional energy sources such as natural gas, oil and coal, which are nonrenewable. Besides being nonrenewable, the harnessing of these resources generally produce by-products which could be potentially harmful to the environment. On the contrary, the generation from renewable energy does not pose environmental degradation. Some examples of renewable energy sources are sunlight, wind, tides, waves and geothermal heat. Wave energy is considered as one of the most promising marine renewable resources and is becoming commercially viable quicker than other renewable technologies at an astonishing growth rate. This paper illustrates the working principle of wave energy converter (WEC) and the availability of wave energy in Malaysia oceans. A good understanding of the behaviour of ocean waves is important for designing an efficient WEC as the characteristics of the waves in shallow and deep water are different. Consequently, wave energy converters are categorized into three categories on shore, near shore and offshore. Therefore, the objectives of this study is ought to be carried out by focusing on the formation of waves and wave characteristics in shallow as well as in deep water. The potential sites for implementation of wave energy harvesting technology in Malaysia and the wave energy available in the respective area were analysed. The potential of wave energy in Malaysia were tabulated and presented with theoretical data. The interaction between motion of waves and heave buoys for optimum phase condition by using the mass and diameter as the variables were investigated.

Ultrasonically-induced electrical potentials in demineralized bovine cortical bone

Science.gov (United States)

Mori, Shunki; Makino, Taiki; Koyama, Daisuke; Takayanagi, Shinji; Yanagitani, Takahiko; Matsukawa, Mami

2018-04-01

While the low-intensity pulsed ultrasound technique has proved useful for healing of bone fractures, the ultrasound healing mechanism is not yet understood. To understand the initial physical effects of the ultrasound irradiation process on bone, we have studied the anisotropic piezoelectric properties of bone in the MHz range. Bone is known to be composed of collagen and hydroxyapatite (HAp) and shows strong elastic anisotropy. In this study, the effects of HAp on the piezoelectricity were investigated experimentally. To remove the HAp crystallites from the bovine cortical bone, demineralization was performed using ethylene diamine tetra-acetic acid (EDTA) solutions. To investigate the piezoelectricity, we have fabricated ultrasound transducers using the cortical bone or demineralized cortical bone. The induced electrical potentials due to the piezoelectricity were observed as the output of these transducers under pulsed ultrasound irradiation in the MHz range. The cortical bone transducer (before mineralization) showed anisotropic piezoelectric behavior. When the ultrasound irradiation was applied normal to the transducer surface, the observed induced electrical potentials had minimum values. The potential increased under off-axis ultrasound irradiation with changes in polarization. In the demineralized bone transducer case, however, the anisotropic behavior was not observed in the induced electrical potentials. These results therefore indicate that the HAp crystallites affect the piezoelectric characteristics of bone.

Authorial and institutional stratification in open access publishing: the case of global health research.

Science.gov (United States)

Siler, Kyle; Haustein, Stefanie; Smith, Elise; Larivière, Vincent; Alperin, Juan Pablo

2018-01-01

Using a database of recent articles published in the field of Global Health research, we examine institutional sources of stratification in publishing access outcomes. Traditionally, the focus on inequality in scientific publishing has focused on prestige hierarchies in established print journals. This project examines stratification in contemporary publishing with a particular focus on subscription vs. various Open Access (OA) publishing options. Findings show that authors working at lower-ranked universities are more likely to publish in closed/paywalled outlets, and less likely to choose outlets that involve some sort of Article Processing Charge (APCs; gold or hybrid OA). We also analyze institutional differences and stratification in the APC costs paid in various journals. Authors affiliated with higher-ranked institutions, as well as hospitals and non-profit organizations pay relatively higher APCs for gold and hybrid OA publications. Results suggest that authors affiliated with high-ranked universities and well-funded institutions tend to have more resources to choose pay options with publishing. Our research suggests new professional hierarchies developing in contemporary publishing, where various OA publishing options are becoming increasingly prominent. Just as there is stratification in institutional representation between different types of publishing access, there is also inequality within access types.

Optimising preoperative risk stratification tools for prostate cancer using mpMRI

Energy Technology Data Exchange (ETDEWEB)

Reisaeter, Lars A.R.; Losnegaard, Are; Biermann, Martin; Roervik, Jarle [Haukeland University Hospital, Department of Radiology, Bergen (Norway); University of Bergen, Department of Clinical Medicine, Bergen (Norway); Fuetterer, Jurgen J. [Radboud University Nijmegen Medical Centre, Department of Radiology, Nijmegen (Netherlands); Nygaard, Yngve [Haukeland University Hospital, Department of Urology, Bergen (Norway); Monssen, Jan [Haukeland University Hospital, Department of Radiology, Bergen (Norway); Gravdal, Karsten [Haukeland University Hospital, Department of Pathology, Bergen (Norway); Halvorsen, Ole J.; Akslen, Lars A. [Haukeland University Hospital, Department of Pathology, Bergen (Norway); Centre for Cancer Biomarkers CCBIO, Department of Clinical Medicine, University of Bergen (Norway); Haukaas, Svein; Beisland, Christian [University of Bergen, Department of Clinical Medicine, Bergen (Norway); Haukeland University Hospital, Department of Urology, Bergen (Norway)

2018-03-15

To improve preoperative risk stratification for prostate cancer (PCa) by incorporating multiparametric MRI (mpMRI) features into risk stratification tools for PCa, CAPRA and D'Amico. 807 consecutive patients operated on by robot-assisted radical prostatectomy at our institution during the period 2010-2015 were followed to identify biochemical recurrence (BCR). 591 patients were eligible for final analysis. We employed stepwise backward likelihood methodology and penalised Cox cross-validation to identify the most significant predictors of BCR including mpMRI features. mpMRI features were then integrated into image-adjusted (IA) risk prediction models and the two risk prediction tools were then evaluated both with and without image adjustment using receiver operating characteristics, survival and decision curve analyses. 37 patients suffered BCR. Apparent diffusion coefficient (ADC) and radiological extraprostatic extension (rEPE) from mpMRI were both significant predictors of BCR. Both IA prediction models reallocated more than 20% of intermediate-risk patients to the low-risk group, reducing their estimated cumulative BCR risk from approximately 5% to 1.1%. Both IA models showed improved prognostic performance with a better separation of the survival curves. Integrating ADC and rEPE from mpMRI of the prostate into risk stratification tools improves preoperative risk estimation for BCR. (orig.)

Electrophysiologic profile and results of invasive risk stratification in asymptomatic children and adolescents with the Wolff-Parkinson-White electrocardiographic pattern.

Science.gov (United States)

Kubuš, Peter; Vít, Pavel; Gebauer, Roman A; Materna, Ondřej; Janoušek, Jan

2014-04-01

Data on the results and clinical effect of an invasive risk stratification strategy in asymptomatic young patients with the Wolff-Parkinson-White electrocardiographic pattern are scarce. Eighty-five consecutive patients agedWolff-Parkinson-White pattern and persistent preexcitation at maximum exercise undergoing invasive risk stratification were retrospectively studied. Adverse accessory pathway (AP) properties were defined according to currently consented criteria as any of the following: shortest preexcited RR interval during atrial fibrillation/rapid atrial pacing≤250 ms (or antegrade effective refractory period≤250 ms if shortest preexcited RR interval was not available) or inducible atrioventricular re-entrant tachycardia. Age at evaluation was median 14.9 years. Eighty-two patients had a structurally normal heart and 3 had hypertrophic cardiomyopathy. A single manifest AP was present in 80, 1 manifest and 1 concealed AP in 4, and 2 manifest APs in 1 patient. Adverse AP properties were present in 32 of 85 patients (37.6%) at baseline and in additional 16 of 44 (36.4%) after isoproterenol. Ablation was performed in 41 of these 48 patients. Ablation was deferred in the remaining 7 for pathway proximity to the atrioventricular node. In addition, 18 of the low-risk patients were ablated based on patient/parental decision. Adverse AP properties at baseline were exhibited by 37.6% of the evaluated patients with an asymptomatic Wolff-Parkinson-White preexcitation persisting at peak exercise. Isoproterenol challenge yielded additional 36.4% of those tested at higher risk. Ablation was performed in a total of 69.4% of patients subjected to invasive risk stratification.

Access, Resources, and Classes in the History of Capitalism: A Theory of Social Stratification from a Cognitive Materialist Perspective

Directory of Open Access Journals (Sweden)

Mariano Zukerfeld

2016-04-01

Full Text Available This article aims to apply some concepts from cognitive materialism to the sociological problem of social stratification in capitalism, both in theoretical and abstract terms and through concrete historical examples. After discussing the necessity for a theory of social classes, a division is presented between two types of resources: those intensive in material and energy, and those which are knowledge intensive. At the same time three alternative conditions of access to these resources are theorized: exclusive access (applicable to physical or intellectual property, non-exclusive access, and no access. Combining the different types of resource with the different types of access, we obtain a proposal for a theory of classes (reclaiming this theory as the most powerful for the analysis of social stratification which we apply, in a simplified and schematic way, to various periods. Thus, we analyze social strata in the transition from feudalism to mercantile capitalism, the subsequent transition to industrial capitalism (in which we distinguish two clearly differentiated stages, and finally, in the current transformation into informational capitalism.

Potential energy function of CN-

Czech Academy of Sciences Publication Activity Database

Špirko, Vladimír; Polák, Rudolf

2008-01-01

Roč. 248, č. 1 (2008), s. 77-80 ISSN 0022-2852 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550511; GA AV ČR IAA400400504 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : potential energy curve * fundamental transition * spectroscopic constants Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.636, year: 2008

Potential energy landscapes of elemental and heterogeneous chalcogen clusters

International Nuclear Information System (INIS)

Mauro, John C.; Loucks, Roger J.; Balakrishnan, Jitendra; Varshneya, Arun K.

2006-01-01

We describe the potential energy landscapes of elemental S 8 , Se 8 , and Te 8 clusters using disconnectivity graphs. Inherent structures include both ring and chain configurations, with rings especially dominant in Se 8 . We also map the potential energy landscapes of heterogeneous Se n (S,Te) 8-n clusters, which offer insights into the structure of heterogeneous chalcogen glasses

[Risk stratification of patients with diabetes mellitus undergoing coronary artery bypass grafting--a comparison of statistical methods].

Science.gov (United States)

Arnrich, B; Albert, A; Walter, J

2006-01-01

Among the coronary bypass patients from our Datamart database, we found a prevalence of 29.6% of diagnosed diabetics. 5.2% of the patients without a diagnosis of diabetes mellitus and a fasting plasma glucose level > 125 mg/dl were defined as undiagnosed diabetics. The objective of this paper was to compare univariate methods and techniques for risk stratification to determine, whether undiagnosed diabetes is per se a risk factor for increased ventilation time and length of ICU stay, and for increased prevalence of resuscitation, reintubation and 30-d mortality for diabetics in heart surgery. Univariate comparisons reveals that undiagnosed diabetics needed resuscitation significantly more often and had an increased ventilation time, while the length of ICU stay was significantly reduced. The significantly different distribution between the diabetics groups of 11 from 32 attributes examined, demands the use of methods for risk stratification. Both risk adjusted methods regression and matching confirm that undiagnosed diabetics had an increased ventilation time and an increased prevalence of resuscitation, while the length of ICU stay was not significantly reduced. A homogeneous distribution of the patient characteristics in the two diabetics groups could be achieved through a statistical matching method using the propensity score. In contrast to the regression analysis, a significantly increased prevalence of reintubation in undiagnosed diabetics was found. Based on an example of undiagnosed diabetics in heart surgery, the presented study reveals the necessity and the possibilities of techniques for risk stratification in retrospective analysis and shows how the potential of data collection from daily clinical practice can be used in an effective way.

Three-tiered risk stratification model to predict progression in Barrett's esophagus using epigenetic and clinical features.

Directory of Open Access Journals (Sweden)

Fumiaki Sato

2008-04-01

Full Text Available Barrett's esophagus predisposes to esophageal adenocarcinoma. However, the value of endoscopic surveillance in Barrett's esophagus has been debated because of the low incidence of esophageal adenocarcinoma in Barrett's esophagus. Moreover, high inter-observer and sampling-dependent variation in the histologic staging of dysplasia make clinical risk assessment problematic. In this study, we developed a 3-tiered risk stratification strategy, based on systematically selected epigenetic and clinical parameters, to improve Barrett's esophagus surveillance efficiency.We defined high-grade dysplasia as endpoint of progression, and Barrett's esophagus progressor patients as Barrett's esophagus patients with either no dysplasia or low-grade dysplasia who later developed high-grade dysplasia or esophageal adenocarcinoma. We analyzed 4 epigenetic and 3 clinical parameters in 118 Barrett's esophagus tissues obtained from 35 progressor and 27 non-progressor Barrett's esophagus patients from Baltimore Veterans Affairs Maryland Health Care Systems and Mayo Clinic. Based on 2-year and 4-year prediction models using linear discriminant analysis (area under the receiver-operator characteristic (ROC curve: 0.8386 and 0.7910, respectively, Barrett's esophagus specimens were stratified into high-risk (HR, intermediate-risk (IR, or low-risk (LR groups. This 3-tiered stratification method retained both the high specificity of the 2-year model and the high sensitivity of the 4-year model. Progression-free survivals differed significantly among the 3 risk groups, with p = 0.0022 (HR vs. IR and p<0.0001 (HR or IR vs. LR. Incremental value analyses demonstrated that the number of methylated genes contributed most influentially to prediction accuracy.This 3-tiered risk stratification strategy has the potential to exert a profound impact on Barrett's esophagus surveillance accuracy and efficiency.

Induced fermion number, phase-shift flip, and the axial anomaly in the Aharonov-Bohm potential

International Nuclear Information System (INIS)

Moroz, A.

1994-01-01

The spectral properties of the Dirac and the Klein-Gordon equations in the Aharonov-Bohm potential are discussed. The density of states for different self-adjoint extensions is calculated. The presence of the bound state manifests itself by asymmetric differential scattering cross sections. The results are applied to several physical quantities: the total energy, induced fermion-number, and the axial anomaly. The predictions of a persistent current in the presence of a cosmic string and a gravitational vortex are made. (author) 41 refs.; 1 fig

First-principles assessment of potential ultrafast laser-induced structural transition in Ni

Energy Technology Data Exchange (ETDEWEB)

Bévillon, E.; Colombier, J.P., E-mail: jean.philippe.colombier@univ-st-etienne.fr; Stoian, R.

2016-06-30

Highlights: • First-principles theory calculations in nonequilibrium conditions. • Electronic temperatures fully and consistently taken into account. • Evaluation of an ultrafast laser-induced solid-to-solid transition in Ni. • Relative energies, phonon spectra and energy path are evaluated. • Discussion on the generation of non-thermal forces in metals. - Abstract: The possibility to trigger ultrafast solid-to-solid transitions in transition metals under femtosecond laser irradiation is investigated by means of first-principles calculations. Electronic heating can drastically modify screening, charge distribution and atomic binding features, potentially determining new structural relaxation paths in the solid phase, before thermodynamic solid-to-liquid transformations set in. Consequently, we evaluate here the effect of electronic excitation on structural stability and conditions for structural transitions. Ni is chosen as a case study for the probability of a solid transition, and the stability of its FCC phase is compared to the non-standard HCP structure while accounting for the heating of the electronic subsystem. From a phonon spectra analysis, we show that the thermodynamic stability order reverses at an electronic temperature of around 10{sup 4} K. Both structures exhibit a dynamic stability, indicating they present a metastability depending on the heating. However, the general hardening of phonon modes with the increase of the electronic temperature points out that no transformation will occur, as confirmed by the study of a typical FCC to HCP diffusionless transformation path, showing an increasing energy barrier. Finally, based on electronic density of states interpretation, the tendency of different metal categories to undergo or not an ultrafast laser-induced structural transition is discussed.

Surface signature of Mediterranean water eddies in the Northeastern Atlantic: effect of the upper ocean stratification

Directory of Open Access Journals (Sweden)

I. Bashmachnikov

2012-11-01

Full Text Available Meddies, intra-thermocline eddies of Mediterranean water, can often be detected at the sea surface as positive sea-level anomalies. Here we study the surface signature of several meddies tracked with RAFOS floats and AVISO altimetry.

While pushing its way through the water column, a meddy raises isopycnals above. As a consequence of potential vorticity conservation, negative relative vorticity is generated in the upper layer. During the initial period of meddy acceleration after meddy formation or after a stagnation stage, a cyclonic signal is also generated at the sea-surface, but mostly the anticyclonic surface signal follows the meddy.

Based on geostrophy and potential vorticity balance, we present theoretical estimates of the intensity of the surface signature. It appears to be proportional to the meddy core radius and to the Coriolis parameter, and inversely proportional to the core depth and buoyancy frequency. This indicates that surface signature of a meddy may be strongly reduced by the upper ocean stratification. Using climatic distribution of the stratification intensity, we claim that the southernmost limit for detection in altimetry of small meddies (with radii on the order of 10–15 km should lie in the subtropics (35–45° N, while large meddies (with radii of 25–30 km could be detected as far south as the northern tropics (25–35° N. Those results agree with observations.

Energy from waste. Potentials and possibilities for usage; Energie aus Abfall. Potenziale und Nutzungsmoeglichkeiten

Energy Technology Data Exchange (ETDEWEB)

Wallmann, Rainer; Fritz, Thomas [Hochschule fuer Angewandte Wissenschaft und Kunst (HAWK), Goettingen (DE). Fachgebiet Nachhaltige Energie- und Umwelttechnik (NEUTec); Fricke, Klaus [Technische Univ. Braunschweig (Germany). Abt. Abfall- und Ressourcenwirtschaft

2009-05-15

In the present article the results of appraisal for the determination of the theoretical potential of energy and the current secondary energy supply of waste streams, which are relevant for the power production in Germany are represented. To sum up, the following conclusions arise from the balance: The theoretical primary energy supply potential of the examined waste streams amounts from 540 to 650 PJ/a and corresponds from 3.9 to 4.6% of the total primary energy consumption in Germany. In consideration of the system-dependent efficiencies and steering of flow patterns for materials altogether approx. 53 PJ electricity and 104 PJ (used) heat were produced as secondary energy within the regarded ranges in the year 2006 in Germany. This corresponds approx. to 1.7% of the final energy consumption in Germany. The outcome of the evaluated energy data for 2006 is a middle energy efficiency of approx. 26.5% (approx. 8.9% electrically and approx. 17.6% thermally). Under technically optimized conditions the power efficiency can be raised possibly on approx. 37%, whereby the share of the final energy consumption in Germany would increase to 2,3%. (orig.)

Improving risk-stratification of Diabetes complications using temporal data mining.

Science.gov (United States)

Sacchi, Lucia; Dagliati, Arianna; Segagni, Daniele; Leporati, Paola; Chiovato, Luca; Bellazzi, Riccardo

2015-01-01

To understand which factor trigger worsened disease control is a crucial step in Type 2 Diabetes (T2D) patient management. The MOSAIC project, funded by the European Commission under the FP7 program, has been designed to integrate heterogeneous data sources and provide decision support in chronic T2D management through patients' continuous stratification. In this work we show how temporal data mining can be fruitfully exploited to improve risk stratification. In particular, we exploit administrative data on drug purchases to divide patients in meaningful groups. The detection of drug consumption patterns allows stratifying the population on the basis of subjects' purchasing attitude. Merging these findings with clinical values indicates the relevance of the applied methods while showing significant differences in the identified groups. This extensive approach emphasized the exploitation of administrative data to identify patterns able to explain clinical conditions.

Energy from streaming current and potential

NARCIS (Netherlands)

Olthuis, Wouter; Schippers, Bob; Eijkel, Jan C.T.; van den Berg, Albert

2005-01-01

It is investigated how much energy can be delivered by a streaming current source. A streaming current and subsequent streaming potential originate when double layer charge is transported by hydrodynamic flow. Theory and a network model of such a source is presented and initial experimental results

Energy independent optical potentials: construction and limitations

International Nuclear Information System (INIS)

Hussein, M.S.; Moniz, E.J.

1983-11-01

Properties of the energy-independent potential U sup(-) which is wave-function-equivalent to the usual optical potential U(E) are constructed and examined. A simple procedure is presented for constructing U sup(-) in the uniform medium, and physical examples are discussed. The general result for finite systems, a recursive expansion in powers of U(E), is used to investigate the multiple scattering expansion of U sup(-); the energy-independent potential is found to have serious short-comings for direct microscopic construction or phenomenological parametrization. The microscopic theory, as exemplified here by the multiple scattering approach, does not lead to a reliable approximation scheme. Phenomenological approaches to U sup(-) are unattractive because the physics does not guide the parametrization effectively: the structure of the nonlocality is not tied directly to the dynamics; Im U sup(-) changes sign; different elements of the physics, separate in U(E), are completely entangled in U sup(-). (Author) [pt

Estimates of the potential for energy conservation in the Chinese steel industry

International Nuclear Information System (INIS)

Lin Boqiang; Wu Ya; Zhang Li

2011-01-01

The study evaluates the energy saving potential of the Chinese steel industry by studying its potential future energy efficiency gap. In order to predict the future energy efficiency gap, a multivariate regression model combined with risk analysis is developed to estimate future energy intensity of China's steel industry. It is found that R and D intensity, energy saving investment, labor productivity and industry concentration are all important variables that affect energy intensity. We assess the possible measures as to how China's steel industry can narrow the energy efficiency gap with Japan by means of scenario analysis. Using Japan's current energy efficiency level as baseline, the energy saving potential of China's steel industry is more than 200 million ton coal equivalent in 2008, and it would fall to zero in 2020. However, if greater efforts were made to conserve energy, it would be possible to narrow down the energy efficiency gap between China and Japan by around 2015. Finally, using the results of the scenario analysis, future policy priorities for energy conservation in China's steel industry are assessed in this paper. - Highlights: → The energy saving potential of the Chinese steel industry is evaluated. → A multivariate regression model combined with risk analysis is developed. → R and D, energy saving investment, labor, and structure affect energy intensity.→ The energy saving potential of China's steel industry would fall to zero in 2020.→ Future policy for energy conservation in China's steel industry are assessed.

Potential Energy Curve of N2 Revisited

Czech Academy of Sciences Publication Activity Database

Špirko, Vladimír; Xiangzhu, L.; Paldus, J.

2011-01-01

Roč. 76, č. 4 (2011), s. 327-341 ISSN 0010-0765 R&D Projects: GA MŠk LC512; GA ČR GAP208/11/0436 Institutional research plan: CEZ:AV0Z40550506 Keywords : reduced multireference coupled-cluster method * reduced potential curve method * nitrogen molecule potential energy curves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.283, year: 2011

A nonlinear flow-induced energy harvester by considering effects of fictitious springs

Science.gov (United States)

Zhang, Guangcheng; Lin, Yueh-Jaw

2018-01-01

In this paper, a newly proposed energy harvesting approach involving nonlinear coupling effects is demonstrated by utilizing a pair of inducing bluff bodies that are put on both sides of the flag-shaped cantilever beam, and placed in a side-by-side configuration to harvest the energy of the flow. One patch of macro fiber composite is attached to the fixed end of the cantilever beam to facilitate converting the kinetic energy into electric power. It is the first time in recent literature that two fluid dynamic phenomena (i.e. the vortex shedding and the Bernoulli effect) are considered simultaneously in the flow-induced energy harvesting field. The fictitious springs are introduced to explain the nonlinear characteristics of the proposed structure. With the effect of the fictitious springs, the speed range of the flow-induced energy harvester is extended. The proposed structure not only improves the output of the induced-based energy harvester compared to one that has just one cylinder, but can also be utilized in an actual hostile ambient environment. The experimental results for the energy harvester prototype are also investigated. The output power of the energy harvester with two cylinders (D = 25 mm) is measured to be 1.12 μW when the flow speed is 0.325 m s-1 and the center-to-center transverse spacing is 45 mm. This research also delves into the geometric variations of the proposed structure and its optimization.

Assessing the Potential for Renewable Energy on National Forest System Lands

Energy Technology Data Exchange (ETDEWEB)

2005-01-01

This technical report and CD for the U.S. Department of Agriculture, Forest Service (USFS), evaluates the potential for renewable energy resource development on National Forest System (NFS) lands. USFS can use the report findings to consider potential for development of solar and wind energy resources on NFS lands, in land management decisions. The Geographical Information System (GIS) based analysis resulted in the following findings: (1) Ninety-nine National Forest Units have high potential for power production from one or more of these solar and wind energy sources; and (2) Twenty National Forest Units in nine states have high potential for power production from two or more of these solar and wind energy sources.

Exploring the transition potential of renewable energy communities

NARCIS (Netherlands)

Doci, G.; Vasileiadou, E.

Renewable energy communities are grassroots initiatives that invest in ‘clean energy’ in order to meet consumption needs and environmental goals and thereby – often unwittingly – conduce to the spread of renewables. Our aim in the present study is to explore the potential of renewable energy

Noninvasive risk stratification for sudden death in asymptomatic patients with Wolff-Parkinson-White syndrome.

Science.gov (United States)

Novella, John; DeBiasi, Ralph M; Coplan, Neil L; Suri, Ranji; Keller, Seth

2014-01-01

Sudden cardiac death (SCD) as the first clinical manifestation of Wolff-Parkinson-White (WPW) syndrome is a well-documented, although rare occurrence. The incidence of SCD in patients with WPW ranges from 0% to 0.39% annually. Controversy exists regarding risk stratification for patients with preexcitation on surface electrocardiogram (ECG), particularly in those who are asymptomatic. This article focuses on the role of risk stratification using exercise and pharmacologic testing in patients with WPW pattern on ECG.

Thermal stratification in a hot water tank established by heat loss from the tank

DEFF Research Database (Denmark)

Fan, Jianhua; Furbo, Simon

2012-01-01

This paper presents numerical investigations of thermal stratification in a vertical cylindrical hot water tank established by standby heat loss from the tank. The transient fluid flow and heat transfer in the tank during cooling caused by standby heat loss are calculated by means of validated...... computational fluid dynamics (CFD) models. The measured heat loss coefficient for the different parts of the tank is used as input to the CFD model. Parametric studies are carried out using the validated models to investigate the influence on thermal stratification of the tank by the downward flow...... the heat loss from the tank sides will be distributed at different levels of the tank at different thermal conditions. The results show that 20–55% of the side heat loss drops to layers below in the part of the tank without the presence of thermal stratification. A heat loss removal factor is introduced...

Thermal stratification in a hot water tank established by heat loss from the tank

DEFF Research Database (Denmark)

Fan, Jianhua; Furbo, Simon

2009-01-01

Results of experimental and numerical investigations of thermal stratification and natural convection in a vertical cylindrical hot water tank during standby periods are presented. The transient fluid flow and heat transfer in the tank during cooling caused by heat loss are investigated...... on the natural buoyancy resulting in downward flow along the tank side walls due to heat loss of the tank and the influence on thermal stratification of the tank by the downward flow and the corresponding upward flow in the central parts of the tank. Water temperatures at different levels of the tank...... by computational fluid dynamics (CFD) calculations and by thermal measurements. A tank with uniform temperatures and thermal stratification is studied. The distribution of the heat loss coefficient for the different parts of the tank is measured by tests and used as input to the CFD model. The investigations focus...

The Effect of an Isogrid on Cryogenic Propellant Behavior and Thermal Stratification

Science.gov (United States)

Oliveira, Justin; Kirk, Daniel R.; Chintalapati, Sunil; Schallhorn, Paul A.; Piquero, Jorge L.; Campbell, Mike; Chase, Sukhdeep

2007-01-01

All models for thermal stratification available in the presentation are derived using smooth, flat plate laminar and turbulent boundary layer models. This study examines the effect of isogrid (roughness elements) on the surface of internal tank walls to mimic the effects of weight-saving isogrid, which is located on the inside of many rocket propellant tanks. Computational Fluid Dynamics (CFD) is used to study the momentum and thermal boundary layer thickness for free convection flows over a wall with generic roughness elements. This presentation makes no mention of actual isogrid sizes or of any specific tank geometry. The magnitude of thermal stratification is compared for smooth and isogrid-lined walls.

Educational stratification in cultural participation: Cognitive competence or status motivation?

NARCIS (Netherlands)

Notten, N.; Bol, Th.; van de Werfhorst, H.G.; Ganzeboom, H.B.G.

2015-01-01

This article examines educational stratification in highbrow cultural participation. There are two contrasting explanations of why cultural participation is stratified. The status hypothesis predicts that people come to appreciate particular forms of art because it expresses their belonging to a

Educational stratification in cultural participation: cognitive competence or status motivation?

NARCIS (Netherlands)

Notten, N.; Lancee, B.; van de Werfhorst, H.G.; Ganzeboom, H.B.G.

2015-01-01

This article examines educational stratification in highbrow cultural participation. There are two contrasting explanations of why cultural participation is stratified. The status hypothesis predicts that people come to appreciate particular forms of art because it expresses their belonging to a

Surrogacy assessment using principal stratification when surrogate and outcome measures are multivariate normal.

Science.gov (United States)

Conlon, Anna S C; Taylor, Jeremy M G; Elliott, Michael R

2014-04-01

In clinical trials, a surrogate outcome variable (S) can be measured before the outcome of interest (T) and may provide early information regarding the treatment (Z) effect on T. Using the principal surrogacy framework introduced by Frangakis and Rubin (2002. Principal stratification in causal inference. Biometrics 58, 21-29), we consider an approach that has a causal interpretation and develop a Bayesian estimation strategy for surrogate validation when the joint distribution of potential surrogate and outcome measures is multivariate normal. From the joint conditional distribution of the potential outcomes of T, given the potential outcomes of S, we propose surrogacy validation measures from this model. As the model is not fully identifiable from the data, we propose some reasonable prior distributions and assumptions that can be placed on weakly identified parameters to aid in estimation. We explore the relationship between our surrogacy measures and the surrogacy measures proposed by Prentice (1989. Surrogate endpoints in clinical trials: definition and operational criteria. Statistics in Medicine 8, 431-440). The method is applied to data from a macular degeneration study and an ovarian cancer study.

The potential of solar energy in the Netherlands

International Nuclear Information System (INIS)

Sinke, W.C.; De Geus, A.C.

1993-01-01

Solar energy in the Netherlands is not yet a well-known phenomenon. Still, the potential of solar energy to save or generate energy is large. Several forms of solar energy, as well as its possibilities and limitations, are introduced in this article. Attention is paid to active and passive thermal solar energy, and photovoltaic solar energy. Also the involvement of different parties in introducing solar energy is discussed. The next 10-20 years will be characterized by large-scale practical experiments and market introduction. The application of solar energy should be taken into account when planning urban areas. It is expected that ongoing developments in all fields of solar energy will result in a considerable improvement of the price/performance ratio and many new possibilities. 4 figs., 4 ills., 14 refs

High protein diet maintains glucose production during exercise-induced energy deficit: a controlled trial

Science.gov (United States)

Inadequate energy intake induces changes in endogenous glucose production (GP) to preserve muscle mass. Whether addition provision of dietary protein modulates GP response to energy deficit is unclear. The objective was to determine whether exercise-induced energy deficit effects on glucose metaboli...

Li breakup polarization potential at near barrier energies

International Nuclear Information System (INIS)

Lubian, F. J.; Correa, T.; Gomes, P.R.S.; Paes, B; Figueira, J. M.; Abriola, D.; Fernandez, J. O.; Capurro, O. A.; Marti, G.V.; Martinez, D.; Heimann; Negri, A.; Pacheco, A. J.; Padron, I.

2007-01-01

Inelastic and one neutron transfer cross sections at energies around the Coulomb barrier were used to derive dynamic polarization potential (DPP) for the 7 Li + 27 Al system. The DPP due to breakup, obtained in a simple way, indicates that its real part is repulsive at nearbarrier energies. (Author)

Planar density of vacuum charge induced by a supercritical Coulomb potential

Directory of Open Access Journals (Sweden)

V.R. Khalilov

2017-06-01

Full Text Available Analytical expressions for the planar density of an induced vacuum charge are obtained in a strong Coulomb potential in coordinate space. Treatment is based on a self-adjoint extension approach for constructing of the Green's function of a charged fermion in an external electromagnetic field. Induced vacuum charge density is calculated and analyzed in subcritical and supercritical Coulomb potentials for massless and massive fermions. We argue that the virtual and so-called real vacuum polarizations contribute in an induced vacuum charge in a supercritical Coulomb potential. The behavior of the polarization vacuum charge density is investigated at long and short distances from the Coulomb center. The induced vacuum charge has a screening sign. Screening of a Coulomb impurity in graphene is briefly discussed. The real vacuum polarization charge density that acquires the quantum electrodynamics vacuum in a supercritical Coulomb potential due to the real vacuum polarization is calculated. It is shown that the vacuum charge densities essentially differ in massive and massless cases. We expect that our results can, as a matter of principle, be tested in graphene with a supercritical Coulomb impurity.

Planar density of vacuum charge induced by a supercritical Coulomb potential

Energy Technology Data Exchange (ETDEWEB)

Khalilov, V.R., E-mail: khalilov@phys.msu.ru; Mamsurov, I.V.

2017-06-10

Analytical expressions for the planar density of an induced vacuum charge are obtained in a strong Coulomb potential in coordinate space. Treatment is based on a self-adjoint extension approach for constructing of the Green's function of a charged fermion in an external electromagnetic field. Induced vacuum charge density is calculated and analyzed in subcritical and supercritical Coulomb potentials for massless and massive fermions. We argue that the virtual and so-called real vacuum polarizations contribute in an induced vacuum charge in a supercritical Coulomb potential. The behavior of the polarization vacuum charge density is investigated at long and short distances from the Coulomb center. The induced vacuum charge has a screening sign. Screening of a Coulomb impurity in graphene is briefly discussed. The real vacuum polarization charge density that acquires the quantum electrodynamics vacuum in a supercritical Coulomb potential due to the real vacuum polarization is calculated. It is shown that the vacuum charge densities essentially differ in massive and massless cases. We expect that our results can, as a matter of principle, be tested in graphene with a supercritical Coulomb impurity.