The expansion of coal mining in the depression areas – a way to development?

Directory of Open Access Journals (Sweden)

Stanislav Martinát

2014-05-01

Full Text Available The coal has been mined in the Karviná area for more than 150 years. During the course of time mining areas were continuously extended at the expense of the settled areas. At the beginnings the mining was limited, but later, namely under conditions of centrally planned economy in the period between 1950s and 1980s, it was heavily intensified. Then, as a result of economic restructuring of the Czech Republic mining was reduced in the region to be re-developed in the last decade again. The expansion of coal mining has been continuously affecting the socio-economic structure of local population (huge working immigration, industrialisation, construction of mass housing for miners – miners dormitories, later housing estates etc., displacement of settlements, surrounding landscape (subsidence of terrain, undermining, hydrological changes and formation of artificial lakes, occurrence of plenty of post-mining brownfields after the reduction of mining etc., but also contemporary outward, image and socio-spatial structure of cities (dominance housing in housing estates, effects of communists spatial urban planning etc.. Currently, negotiations about expansion of coal mining are in progress in this region, namely the city parts of Karviná (Staré Město and Orlová (Výhoda should be affected. In the introductory parts of this paper social, economical and environmental aspects of coal mining on the development of regions and connected problems are discussed and both cities are shortly presented. The questionnaire survey focused on perceptions of after-mining renewal and potential expansion of mining in the area of cities of Karviná and Orlová was conducted (n=1000. As the most important predictor that influences perception of mining and renewal, employment in mining companies has been identified. The higher education respondents achieved, the higher level of opposition against mining was manifested. The correlation was also found between the level of

A Method for Exploring the Link between Urban Area Expansion over Time and the Opportunity for Crime in Saudi Arabia

Directory of Open Access Journals (Sweden)

Mofza Algahtany

2016-10-01

Full Text Available Urban area expansion is one of the most critical types of worldwide change, and most urban areas are experiencing increased growth in population and infrastructure development. Urban change leads to many changes in the daily activities of people living within an affected area. Many studies have suggested that urbanization and crime are related. However, they focused particularly on land uses, types of land use, and urban forms, such as the physical features of neighbourhoods, roads, shopping centres, and bus stations. Understanding the correlation between urban area expansion and crime is very important for criminologists and urban planning decision-makers. In this study, we have used satellite images to measure urban expansion over a 10-year period and tested the correlations between these expansions and the number of criminal activities within these specific areas. The results show that there is a measurable relationship between urban expansion and criminal activities. Our findings support the crime opportunity theory as one possibility, which suggests that population density and crime are conceptually related. We found the correlations are stronger where there has been greater urban growth. Many other factors that may affect crime rate are not included in this paper, such as information on the spatial details of the population, city planning, economic considerations, the distance from the city centre, neighbourhood quality, and police numbers. However, this study will be of particular interest to those who aim to use remote sensing to study patterns of crime.

Thermodynamics of interacting holographic dark energy with the apparent horizon as an IR cutoff

International Nuclear Information System (INIS)

Sheykhi, Ahmad

2010-01-01

As soon as an interaction between holographic dark energy and dark matter is taken into account, the identification of an IR cutoff with the Hubble radius H -1 , in a flat universe, can simultaneously drive accelerated expansion and solve the coincidence problem. Based on this, we demonstrate that in a non-flat universe the natural choice for the IR cutoff could be the apparent horizon radius, r-tilde A =1/√(H 2 +k/a 2 ). We show that any interaction of dark matter with holographic dark energy, whose infrared cutoff is set by the apparent horizon radius, implies an accelerated expansion and a constant ratio of the energy densities of both components thus solving the coincidence problem. We also verify that for a universe filled with dark energy and dark matter, the Friedmann equation can be written in the form of the modified first law of thermodynamics, dE = T h dS h + WdV, at the apparent horizon. In addition, the generalized second law of thermodynamics is fulfilled in a region enclosed by the apparent horizon. These results hold regardless of the specific form of dark energy and interaction term. Our study might reveal that in an accelerating universe with spatial curvature, the apparent horizon is a physical boundary from the thermodynamical point of view.

Potential areas for the expansion of the sugar cane production; Areas potenciais para a expansao da producao de cana-de-acucar

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-10-15

The evaluation of the potential areas for the expansion of the sugar cane cultivation was based on the estimation of the agricultural productivity aptitude as function of the soil and climate characteristics using maps with geo referred in scales of 1/5,000,000. Areas had been discarded which integrate of three large biomass of the country: Amazonia, Pantanal and Mata Atlantica, and all the areas with some type of restriction, such as environmental reservations, national parks, indigenous, military and urban areas. Were not considered areas with crop mechanization essential for the environmental and social sustainability with declivity more than 12%.

Frequency of hepatitis B surface antigen and anti-hepatitis c antibodies in apparently healthy blood donors in northern areas

International Nuclear Information System (INIS)

Alam, M.; Naeem, M.A.

2007-01-01

To determine the frequency of HBsAg and anti HCV among the potential blood donors belonging to Northern areas.A total of 8949 apparently healthy blood donors, belonging to Northern areas were screened for HBsAg and anti-HCV by rapid method.Overall sero-positivity of HBsAg was 3.66% and anti-HCV 1.35%. The result indicates that frequency of HBsAg is more than anti-HCV in Northern areas. (author)

Correlations between Socioeconomic Drivers and Indicators of Urban Expansion: Evidence from the Heavily Urbanised Shanghai Metropolitan Area, China

Directory of Open Access Journals (Sweden)

Jinghui Li

2017-07-01

Full Text Available Rapid urban expansion resulting in increased impervious surfaces causes a series of urban environmental problems, e.g., the urban heat island and urban forest fragmentation. Urban expansion is a serious threat to human quality of life and living environments. It has been studied from a variety of aspects, but its driving factors and time series expansion characteristics (i.e., expansion intensity, pattern and direction need to be better explained in order to devise more effective management strategies. This study examined how social and economic factors are linked in driving urban expansion. Based on multi-temporal aerial images, a rapid urban expansion period, 2000–2010, in Shanghai was analysed. The urban area expanded from 1770.36 to 2855.44 km2 in the period, with a mean annual expansion rate of 108.51 km2. Urban expansion in 2000–2005 (40.42% was much faster than in 2005–2010 (14.86%, and its direction was southeast, southwest and south. The main pattern was edge expansion in both sub-periods. Social factors, especially population density, significantly affected urban expansion. These findings can help understand the urban expansion process and its driving factors, which has important implications for urban planning and management in Shanghai and similar cities.

A new framework for modeling urban land expansion in peri-urban area by combining multi-source datasets and data assimilation

Science.gov (United States)

Zhang, Z.; Xiao, R.; Li, X.

2015-12-01

Peri-urban area is a new type region under the impacts of both rural Industrialization and the radiation of metropolitan during rapid urbanization. Due to its complex natural and social characteristics and unique development patterns, many problems such as environmental pollution and land use waste emerged, which became an urgent issue to be addressed. Study area in this paper covers three typical peri-urban districts (Pudong, Fengxian and Jinshan), which around the Shanghai inner city. By coupling cellular automata and multi-agent system model as the basic tools, this research focus on modelling the urban land expansion and driving mechanism in peri-urban area. The big data is aslo combined with the Bayesian maximum entropy method (BME) for spatiotemporal prediction of multi-source data, which expand the dataset of urban expansion models. Data assimilation method is used to optimize the parameters of the coupling model and minimize the uncertainty of observations, improving the precision of future simulation in peri-urban area. By setting quantitative parameters, the coupling model can effectively improve the simulation of the process of urban land expansion under different policies and management schemes, in order to provide scientificimplications for new urbanization strategy. In this research, we precise the urban land expansion simulation and prediction for peri-urban area, expand the scopes and selections of data acquisition measurements and methods, develop the new applications of the data assimilation method in geographical science, provide a new idea for understanding the inherent rules of urban land expansion, and give theoretical and practical support for the peri-urban area in urban planning and decision making.

Sound Transmission in a Duct with Sudden Area Expansion, Extended Inlet, and Lined Walls in Overlapping Region

Directory of Open Access Journals (Sweden)

Ahmet Demir

2016-01-01

Full Text Available The transmission of sound in a duct with sudden area expansion and extended inlet is investigated in the case where the walls of the duct lie in the finite overlapping region lined with acoustically absorbent materials. By using the series expansion in the overlap region and using the Fourier transform technique elsewhere we obtain a Wiener-Hopf equation whose solution involves a set of infinitely many unknown expansion coefficients satisfying a system of linear algebraic equations. Numerical solution of this system is obtained for various values of the problem parameters, whereby the effects of these parameters on the sound transmission are studied.

SABRE observations of structured ionospheric flows during substorm expansion phase onset

Directory of Open Access Journals (Sweden)

E. G. Bradshaw

1994-08-01

Full Text Available The irregularity velocity patterns observed by the SABRE coherent radar at substorm expansion phase onset, which is identified by magnetometer observations of Pi2 pulsations, are occasionally highly structured. In all the examples of structured velocity patterns examined, the SABRE viewing area is located at longitudes within the inferred substorm current wedge. Three types of structured velocity regime are apparent depending on the level of magnetic activity and the position of the radar viewing area relative to the substorm enhanced currents and the Pi2 pulsation generation region. Firstly, vortex-like velocity patterns are observed and these may be caused by the field-aligned currents associated with the substorm current wedge. Secondly, regions of equatorward velocity are also observed at times of substorm expansion phase onset moving longitudinally across the SABRE viewing area. The longitudinal movement is usually westward although an example of eastward motion has been observed. The phase velocity of these regions of equatorward flow is typically 1-3 km s-1. The observed equatorward velocities occur at the poleward edge or poleward of the background convection velocities observed by SABRE. These equatorward velocities may be related to the westward travelling surge and to the expansion (eastwards as well as westwards of the brightening arc region at substorm onset. Thirdly, the flow rotates equatorward within the field of view but does not then appear to move longitudinally. These equatorward velocities may relate to the earthward surge of plasma from the magnetotail at substorm onset.

Gravitational pressure, apparent horizon and thermodynamics of FLRW universe in the teleparallel gravity

Science.gov (United States)

da Rocha-Neto, J. F.; Morais, B. R.

2018-04-01

In the context of the teleparallel equivalent of general relativity the concept of gravitational pressure and gravitational energy-momentum arisen in a natural way. In the case of a Friedmann-Lemaitre-Robertson-Walker space FLRW we obtain the total energy contained inside the apparent horizon and the radial pressure over the apparent horizon area. We use these definitions to written a thermodynamics relation TAdSA = dEA+PAdVA at the apparent horizon, where EA is the total energy inside the apparent horizon, VA is the areal volume of the apparent horizon, PA is the radial pressure over the apparent horizon area, SA is the entropy which can be assumed as one quarter of the apparent horizon area only for a non stationary apparent horizon. We identify TA as the temperature at the surface of the apparent horizon. We shown that for all expanding accelerated FLRW model of universe the radial pressure is positive.

Apparent molar volumes and compressibilities of alkaline earth metal ions in methanol and dimethylsulfoxide

International Nuclear Information System (INIS)

Warminska, Dorota; Wawer, Jaroslaw; Grzybkowski, Waclaw

2010-01-01

Temperature dependencies of density of magnesium (II), calcium (II), strontium (II), barium (II) perchlorates as well as beryllium (II), and sodium trifluoromethanesulfonates in methanol and dimethylsulfoxide have been determined over the composition range studied. From density data the apparent molar volumes and partial molar volumes of the salts at infinite dilution as well as the expansibilities have been evaluated. The apparent molar isentropic compressibilities of alkaline earth metal perchlorates and beryllium (II) and sodium triflates in methanol and DMSO have been calculated from sound speed data obtained at T = 298.15 K.

Monitoring urban expansion and land use/land cover changes of Shanghai metropolitan area during the transitional economy (1979-2009) in China.

Science.gov (United States)

Yin, Jie; Yin, Zhane; Zhong, Haidong; Xu, Shiyuan; Hu, Xiaomeng; Wang, Jun; Wu, Jianping

2011-06-01

This study explored the spatio-temporal dynamics and evolution of land use/cover changes and urban expansion in Shanghai metropolitan area, China, during the transitional economy period (1979-2009) using multi-temporal satellite images and geographic information systems (GIS). A maximum likelihood supervised classification algorithm was employed to extract information from four landsat images, with the post-classification change detection technique and GIS-based spatial analysis methods used to detect land-use and land-cover (LULC) changes. The overall Kappa indices of land use/cover change maps ranged from 0.79 to 0.89. Results indicated that urbanization has accelerated at an unprecedented scale and rate during the study period, leading to a considerable reduction in the area of farmland and green land. Findings further revealed that water bodies and bare land increased, obviously due to large-scale coastal development after 2000. The direction of urban expansion was along a north-south axis from 1979 to 2000, but after 2000 this growth changed to spread from both the existing urban area and along transport routes in all directions. Urban expansion and subsequent LULC changes in Shanghai have largely been driven by policy reform, population growth, and economic development. Rapid urban expansion through clearing of vegetation has led to a wide range of eco-environmental degradation.

Construction area expansion in relation to economic-demographic development and land resource in the Pearl River Delta of China

NARCIS (Netherlands)

Liu, Zhijia; Huang, Heqing; Werners, Saskia E.; Yan, Dan

2016-01-01

Since 1979, the Pearl River Delta (PRD) of China has experienced rapid socioeconomic development along with a fast expansion of construction area. Affected by both natural and human factors, a complex interdependency is found among the regional changes in construction area, GDP and population. A

Multimodal method for scattering of sound at a sudden area expansion in a duct with subsonic flow

Science.gov (United States)

Kooijman, G.; Testud, P.; Aurégan, Y.; Hirschberg, A.

2008-03-01

The scattering of sound at a sudden area expansion in a duct with subsonic mean flow has been modelled with a multimodal method. Technological applications are for instance internal combustion engine exhaust silencers and silencers in industrial duct systems. Both two-dimensional (2D) rectangular and 2D cylindrical geometry and uniform mean flow as well as non-uniform mean flow profiles are considered. Model results for the scattering of plane waves in case of uniform flow, in which case an infinitely thin shear layer is formed downstream of the area expansion, are compared to results obtained by other models in literature. Generally good agreement is found. Furthermore, model results for the scattering are compared to experimental data found in literature. Also here fairly good correspondence is observed. When employing a turbulent pipe flow profile in the model, instead of a uniform flow profile, the prediction for the downstream transmission- and upstream reflection coefficient is improved. However, worse agreement is observed for the upstream transmission and downstream reflection coefficient. On the contrary, employing a non-uniform jet flow profile, which represents a typical shear layer flow downstream of the expansion, gives worse agreement for the downstream transmission- and the upstream reflection coefficient, whereas prediction for the upstream transmission and downstream reflection coefficient improves.

Multimodal method for scattering of sound at a sudden area expansion in a duct with subsonic flow

NARCIS (Netherlands)

Kooijman, G.; Testud, P.; Aurégan, Y.; Hirschberg, A.

2008-01-01

The scattering of sound at a sudden area expansion in a duct with subsonic mean flow has been modelled with a multimodal method. Technological applications are for instance internal combustion engine exhaust silencers and silencers in industrial duct systems. Both two-dimensional (2D) rectangular

[Prediction and simulation of urban area expansion in Pearl River Delta Region under the RCPs climate scenarios].

Science.gov (United States)

Jiang, Oun-ou; Deng, Xiang-zheng; Ke, Xin-li; Zhao, Chun-hong; Zhang, Wei

2014-12-01

The sizes and number of cities in China are increasing rapidly and complicated changes of urban land use system have occurred as the social economy develops rapidly. This study took the urban agglomeration of Pearl River Delta Region as the study area to explore the driving mechanism of dynamic changes of urban area in the urbanization process under the joint influence of natural environment and social economic conditions. Then the CA (cellular automata) model was used to predict and simulate the urban area changes until 2030 under the designed scenarios of planning and RCPs (representative concentration pathways). The results indicated that urbanization was mainly driven by the non-agricultural population growth and social-economic development, and the transportation had played a fundamental role in the whole process, while the areas with high elevation or steep slope restricted the urbanization. Besides, the urban area would keep an expanding trend regardless of the scenarios, however, the expanding speed would slow down with different inflection points under different scenarios. The urban expansion speed increased in the sequence of the planning scenario, MESSAGE scenario and AIM scenario, and that under the MESSAGE climate scenario was more consistent with the current urban development trend. In addition, the urban expansion would mainly concentrate in regions with the relatively high urbanization level, e.g., Guangzhou, Dongguan, Foshan, Shenzhen, Zhanjiang and Chaoshan.

Characterizing Factors Associated with Built-Up Land Expansion in Urban and Non-Urban Areas from a Morphological Perspective

Directory of Open Access Journals (Sweden)

Zhonghao Zhang

2017-08-01

Full Text Available In this paper, built-up land expansion patterns and the associated factors were characterized in urban and non-urban areas across the Wen-Tai region of eastern China. Fractal dimension can be used as a reliable indicator of the complexity of built-up land form, and the increasing trend of fractal dimension indicated a more complex, dispersed pattern of built-up land in urban areas. Spatial regression models were quantitatively implemented to identify the indicators influencing the variation of fractal dimensions. Our findings suggested that the fractal dimension of built-up land forms was positively correlated to the patch density and elevation when built-up land expansion was more concentrated. Both landscape shape index and Gross Domestic Product (GDP were positively correlated with fractal dimension in urban areas, and total edge, edge density, and connective index had impacts on fractal dimension in non-urban areas. Slope and agricultural population also showed an influence on fractal dimension. This study provided a new way for urban studies in interpreting the complex interactions between fractal dimension and related factors. The combined approach of fractal dimension and spatial analysis can provide the government planners with valuable information that can be efficiently used to realize the influences of land use policies in urban and non-urban areas.

Nearly extremal apparent horizons in simulations of merging black holes

Science.gov (United States)

Lovelace, Geoffrey; Scheel, Mark; Owen, Robert; Giesler, Matthew; Katebi, Reza; Szilagyi, Bela; Chu, Tony; Demos, Nicholas; Hemberger, Daniel; Kidder, Lawrence; Pfeiffer, Harald; Afshari, Nousha; SXS Collaboration

2015-04-01

The spin S of a Kerr black hole is bounded by the surface area A of its apparent horizon: 8 πS A and e0 > 1 , but these surfaces are always surrounded by apparent horizons with 8 πS < A and e0 < 1 .

Glass transition and thermal expansivity of polystyrene thin films

International Nuclear Information System (INIS)

Inoue, R.; Kanaya, T.; Miyazaki, T.; Nishida, K.; Tsukushi, I.; Shibata, K.

2006-01-01

We have studied glass transition temperature and thermal expansivity of polystyrene thin films supported on silicon substrate using X-ray reflectivity and inelastic neutron scattering techniques. In annealing experiments, we have found that the reported apparent negative expansivity of polymer thin films is caused by unrelaxed structure due to insufficient annealing. Using well-annealed films, we have evaluated glass transition temperature T g and thermal expansivity as a function of film thickness. The glass transition temperature decreases with film thickness and is constant below about 10 nm, suggesting the surface glass transition temperature of 355 K, which is lower than that in bulk. We have also found that the thermal expansivity in the glassy state decreases with film thickness even after annealing. The decrease has been attributed to hardening of harmonic force constant arising from chain confinement in a thin film. This idea has been confirmed in the inelastic neutron scattering measurements

Glass transition and thermal expansivity of polystyrene thin films

Energy Technology Data Exchange (ETDEWEB)

Inoue, R. [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan); Kanaya, T. [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan)]. E-mail: kanaya@scl.kyoto-u.ac.jp; Miyazaki, T. [Nitto Denko Corporation, 1-1-2 Shimohozumi, Ibaraki, Osaka-fu 567-8680 (Japan); Nishida, K. [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan); Tsukushi, I. [Chiba Institute of Technology, Narashino, Chiba-ken 275-0023 (Japan); Shibata, K. [Japan Atomic Energy Research Institute, Tokai, Ibaraki-ken 319-1195 (Japan)

2006-12-20

We have studied glass transition temperature and thermal expansivity of polystyrene thin films supported on silicon substrate using X-ray reflectivity and inelastic neutron scattering techniques. In annealing experiments, we have found that the reported apparent negative expansivity of polymer thin films is caused by unrelaxed structure due to insufficient annealing. Using well-annealed films, we have evaluated glass transition temperature T {sub g} and thermal expansivity as a function of film thickness. The glass transition temperature decreases with film thickness and is constant below about 10 nm, suggesting the surface glass transition temperature of 355 K, which is lower than that in bulk. We have also found that the thermal expansivity in the glassy state decreases with film thickness even after annealing. The decrease has been attributed to hardening of harmonic force constant arising from chain confinement in a thin film. This idea has been confirmed in the inelastic neutron scattering measurements.

Mapping Brazilian Cropland Expansion, 2000-2013

Science.gov (United States)

Zalles, V.; Hansen, M.; Potapov, P.

2016-12-01

Brazil is one of the world's leading producers and exporters of agricultural goods. Despite undergoing significant increases in its cropland area in the last decades, it remains one of the countries with the most potential for further agricultural expansion. Most notably, the expansion in production areas of commodity crops such as soybean, corn, and sugarcane has become the leading cause of land cover conversion in Brazil. Natural land covers, such as the Amazon and Cerrado forests, have been negatively affected by this agricultural expansion, causing carbon emissions, biodiversity loss, altered water cycles, and many other disturbances to ecosystem services. Monitoring of change in cropland area extent can provide relevant information to decision makers seeking to understand and manage land cover change drivers and their impacts. In this study, the freely-available Landsat archive was leveraged to produce a large-scale, methodologically consistent map of cropland cover at 30 m. resolution for the entire Brazilian territory in the year 2000. Additionally, we mapped cropland expansion from 2000 to 2013, and used statistical sampling techniques to accurately estimate cropland area per Brazilian state. Using the Global Forest Change product produced by Hansen et al. (2013), we can disaggregate forest cover loss due to cropland expansion by year, revealing spatiotemporal trends that could advance our understanding of the drivers of forest loss.

Apparent molar volumes and isentropic compressibilities of benzyltrialkylammonium chlorides in water at (293.15, 303.15, 313.15, 323.15, and 333.15) K

International Nuclear Information System (INIS)

Duman, Osman; Ayranci, Erol

2009-01-01

Densities and ultrasound speeds of benzyltrialkylammonium chlorides (BTAACls) were measured accurately in aqueous solutions at five temperatures (293.15, 303.15, 313.15, 323.15, and 333.15) K. The data were utilized in determining apparent molar volumes, V Φ , and apparent molar isentropic compressibilities, K SΦ . Infinite dilution values of these apparent molar quantities, V Φ 0 andK SΦ 0 , were determined by extrapolation procedures. Contribution of CH 2 groups, along the alkyl groups of BTAACls, to V Φ 0 andK SΦ 0 values were derived from plots of these quantities as a function of number of additional CH 2 groups in going from benzyltrimethylammonium chloride to benzyltributylammonium chloride. The temperature dependencies of V Φ 0 andK SΦ 0 values were examined on the basis of isobaric expansivity. Apparent molar isobaric expansivities at infinite dilution, E Φ 0 , were obtained from the slopes of V Φ 0 versus temperature data. Concentration dependencies of V Φ and K SΦ were examined. A fair correlation was observed between V Φ 0 andK SΦ 0 values of the three BTAACls.

Mapping the expansion of galamsey gold mines in the cocoa growing area of Ghana using optical remote sensing

Science.gov (United States)

Snapir, B.; Simms, D. M.; Waine, T. W.

2017-06-01

Artisanal gold mining (galamsey) and cocoa farming are essential sources of income for local populations in Ghana. Unfortunately the former poses serious threats to the environment and human health, and conflicts with cocoa farming and other livelihoods. Timely and spatially referenced information on the extent of galamsey is needed to understand and limit the negative impacts of mining. To address this, we use multi-date UK-DMC2 satellite images to map the extent and expansion of galamsey from 2011 to 2015. We map the total area of galamsey in 2013 over the cocoa growing area, using k-means clustering on a cloud-free 2013 image with strong spectral contrast between galamsey and the surrounding vegetation. We also process a pair of hazy images from 2011 and 2015 with Multivariate Alteration Detection to map the 2011-2015 galamsey expansion in a subset, labelled the change area. We use a set of visually interpreted random sample points to compute bias-corrected area estimates. We also delineate an indicative impact zone of pollution proportional to the density of galamsey, assuming a maximum radius of 10 km. In the cocoa growing area of Ghana, the estimated total area of galamsey in 2013 is 27,839 ha with an impact zone of 551,496 ha. In the change area, galamsey has more than tripled between 2011 and 2015, resulting in 603 ha of direct encroachment into protected forest reserves. Assuming the same growth rate for the rest of the cocoa growing area, the total area of galamsey in 2015 is estimated at 43,879 ha. Galamsey is developing along most of the river network (Offin, Ankobra, Birim, Anum, Tano), with downstream pollution affecting both land and water.

National Training Center Fort Irwin expansion area aquatic resources survey

Energy Technology Data Exchange (ETDEWEB)

Cushing, C.E.; Mueller, R.P.

1996-02-01

Biologists from Pacific Northwest National Laboratory (PNNL) were requested by personnel from Fort Irwin to conduct a biological reconnaissance of the Avawatz Mountains northeast of Fort Irwin, an area for proposed expansion of the Fort. Surveys of vegetation, small mammals, birds, reptiles, amphibians, and aquatic resources were conducted during 1995 to characterize the populations and habitats present with emphasis on determining the presence of any species of special concern. This report presents a description of the sites sampled, a list of the organisms found and identified, and a discussion of relative abundance. Taxonomic identifications were done to the lowest level possible commensurate with determining the status of the taxa relative to its possible listing as a threatened, endangered, or candidate species. Consultation with taxonomic experts was undertaken for the Coleoptera ahd Hemiptera. In addition to listing the macroinvertebrates found, the authors also present a discussion related to the possible presence of any threatened or endangered species or species of concern found in Sheep Creek Springs, Tin Cabin Springs, and the Amargosa River.

Apparent molar volumes and compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates in dimethylsulfoxide

International Nuclear Information System (INIS)

Warmińska, Dorota; Wawer, Jarosław

2012-01-01

Highlights: ► Sequence of volumes and compressibilities of Ln 3+ ions in DMSO is: La 3+ > Gd 3+ 3+ . ► Sequence of the partial molar volumes do not change with temperature. ► These results are the consequence of nature of the ion–solvent bonding. - Abstract: Temperature dependencies of the densities of dimethylsulfoxide solutions of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been determined over a wide range of concentrations. The apparent molar volumes and partial molar volumes of the salts at infinite dilution, as well as the expansibilities of the salts, have been calculated from density data. Additionally, the apparent molar isentropic compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been calculated from sound velocity data at 298.15 K. The data obtained have been interpreted in terms of ion−solvent interactions.

Estimating true instead of apparent survival using spatial Cormack-Jolly-Seber models

Science.gov (United States)

Schaub, Michael; Royle, J. Andrew

2014-01-01

Survival is often estimated from capture–recapture data using Cormack–Jolly–Seber (CJS) models, where mortality and emigration cannot be distinguished, and the estimated apparent survival probability is the product of the probabilities of true survival and of study area fidelity. Consequently, apparent survival is lower than true survival unless study area fidelity equals one. Underestimation of true survival from capture–recapture data is a main limitation of the method.

Expansive cements for the manufacture of the concrete protective bandages

Science.gov (United States)

Yakymechko, Yaroslav; Voloshynets, Vladyslav

2017-12-01

One of the promising directions of the use of expansive cements is making the protective bandages for the maintenance of pipelines. Bandages expansive application of the compositions of the pipeline reinforce the damaged area and reduce stress due to compressive stress in the cylindrical area. Such requirements are best suited for expansive compositions obtained from portland cement and modified quicklime. The article presents the results of expansive cements based on quick lime in order to implement protective bandages pipelines.

Thermodynamics of the Apparent Horizon in FRW Universe with Massive Gravity

International Nuclear Information System (INIS)

Li Hui; Zhang Yi

2013-01-01

Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive gravity model in cosmology proposed lately, the corrected entropic formula of the apparent horizon is obtained with the help of the modified Friedmann equations. This entropy-area relation, together with the identified Misner-Sharp internal energy, verifies the first law of thermodynamics for the apparent horizon with a volume change term for consistency. On the other hand, by means of the corrected entropy-area formula and the Clausius relation δQ = T d S, where the heat Bow δQ is the energy-supply of pure matter projecting on the vector ξ tangent to the apparent horizon and should be looked on as the amount of energy crossing the apparent horizon during the time interval dt and the temperature of the apparent horizon for energy crossing during the same interval is 1/(2πr A ), the modified Friedmann equations governing the dynamical evolution of the universe are reproduced with the known energy density and pressure of massive graviton. The integration constant is found to correspond to a cosmological term which could be absorbed into the energy density of matter. Having established the correspondence of massive cosmology with the unified first law of thermodynamics on the apparent horizon, the validity of the generalized second law of thermodynamics is also discussed by assuming the thermal equilibrium between the apparent horizon and the matter field bounded by the apparent horizon. It is found that, in the limit H c → 0, which recovers the Minkowski reference metric solution in the fiat case, the generalized second law of thermodynamics holds if α 3 + 4α 4 3 = α 4 = 0, the generalized second law of thermodynamics could be violated. (general)

Measurement of Apparent Thermal Conductivity of JSC-1A Under Ambient Pressure

Science.gov (United States)

Yuan, Zeng-Guang; Kleinhenz, Julie E.

2011-01-01

The apparent thermal conductivity of JSC-1A lunar regolith simulant was measured experimentally using a cylindrical apparatus. Eleven thermocouples were embedded in the simulant bed to obtain the steady state temperature distribution at various radial, axial, and azimuthal locations. The high aspect ratio of a cylindrical geometry was proven to provide a one-dimensional, axisymmetric temperature field. A test series was performed at atmospheric pressure with varying heat fluxes. The radial temperature distribution in each test fit a logarithmic function, indicating a constant thermal conductivity throughout the soil bed. However, thermal conductivity was not constant between tests at different heat fluxes. This variation is attributed to stresses created by thermal expansion of the simulant particles against the rigid chamber wall. Under stress-free conditions (20 deg C), the data suggest a temperature independent apparent conductivity of 0.1961 +/- 0.0070 W/m/ deg C

Iron, Oil, and Emeryville: Resource Industrialization and Metropolitan Expansion in the San Francisco Bay Area, 1850-1900

OpenAIRE

Lunine, Seth

2013-01-01

Scholars have largely overlooked the formative role of industry in both California's economic development and the San Francisco Bay Area's metropolitan expansion during the late nineteenth century. Beginning in the early 1880s, leading firms in San Francisco's specialized industries, such as the iron and chemicals sectors, dispersed to the metropolitan periphery. This process of industrial suburbanization created an integrative metropolitan economy, as well as individual suburbs. In this di...

Future urban land expansion and implications for global croplands.

Science.gov (United States)

Bren d'Amour, Christopher; Reitsma, Femke; Baiocchi, Giovanni; Barthel, Stephan; Güneralp, Burak; Erb, Karl-Heinz; Haberl, Helmut; Creutzig, Felix; Seto, Karen C

2017-08-22

Urban expansion often occurs on croplands. However, there is little scientific understanding of how global patterns of future urban expansion will affect the world's cultivated areas. Here, we combine spatially explicit projections of urban expansion with datasets on global croplands and crop yields. Our results show that urban expansion will result in a 1.8-2.4% loss of global croplands by 2030, with substantial regional disparities. About 80% of global cropland loss from urban expansion will take place in Asia and Africa. In both Asia and Africa, much of the cropland that will be lost is more than twice as productive as national averages. Asia will experience the highest absolute loss in cropland, whereas African countries will experience the highest percentage loss of cropland. Globally, the croplands that are likely to be lost were responsible for 3-4% of worldwide crop production in 2000. Urban expansion is expected to take place on cropland that is 1.77 times more productive than the global average. The loss of cropland is likely to be accompanied by other sustainability risks and threatens livelihoods, with diverging characteristics for different megaurban regions. Governance of urban area expansion thus emerges as a key area for securing livelihoods in the agrarian economies of the Global South.

Expansion of Sugarcane area for Ethanol production in Brazil: a Threat to Food Production and Environmental Sustainability?

Science.gov (United States)

Monteiro, J. M.; Coutinho, H. L.; Veiga, L. B.

2012-12-01

The raise in fossil fuels prices and the increase in Greenhouse Gas emissions is leading nations to adopt non-fossil fuels based energy sources. Sugarcane crops for biofuel production are expanding fast in Brazil, mainly through land use change (LUC) processes, in substitution of pasturelands and grain crops plantations. Would these changes affect negatively sustainability assessments of bioethanol production in the future? We estimate the extent of sugarcane cropland needed to produce sufficient ethanol to attend to market demands. This work presents a baseline scenario for sugarcane cropping area in Brazil in 2017, taking into account market forces (supply and demand). We also comment on a policy instrument targetting sustainable sugarcane production in Brazil. The expansion scenarios took into account the demand for ethanol from 2008-2017, produced by the Energy Research Corporation, of Brazil. In order to develop the expansion scenario, we estimated the amount of sugarcane needed to attend the ethanol demand. We then calculated the area needed to generate that amount of sugarcane. The analytical parameters were: 1) one tonne of sugarcane produces an average 81.6 liters of ethanol; 2) the average sugarcane crop productivity varied linearly from 81.4 tons/hectare in 2008 to 86.2 tons/hectare in 2017. We also assumed that sugarcane productivity in 2017 as the current average productivity of sugarcane in the State of São Paulo. The results show that the requirement for 3.5 million ha in 2007 will increase to 9 million ha in 2017. The Sugarcane Agroecologic Zoning (ZAECANA), published by Embrapa (2009), is a tool that not only informs the territory occupation and use policies, but also classifies land as qualified, restricted or non-qualified for the plantation of sugarcane crops. The ZAECANA is based on soil and climate suitability assessments, and is presented in a spatially-explicit format. Adopting the precautionary principle, a national policy was established

Thermal expansion of organic superconductor κ-(D4-BEDT-TTF)2Cu{N(CN)2}Br. Isotopic effect

Science.gov (United States)

Dolbin, A. V.; Khlistuck, M. V.; Eselson, V. B.; Gavrilko, V. G.; Vinnikov, N. A.; Basnukaeva, R. M.; Konstantinov, V. A.; Nakazawa, Y.

2017-12-01

Linear thermal expansion coefficient (LTEC) of single crystal κ-(D4-BEDT-TTF)2Cu[N(CN)2]Br was studied across the crystal layers in the temperature range 2-290 K using the method of precise capacitive dilatometry. Below Tc = 11.6 K the LTEC of the sample had a small negative value, which is apparently due to the transition from the paramagnetic metal in the superconducting state. There was a bend of temperature dependence of the LTEC, which shows broad peak around 40 K and can be attributed to the elastic lattice anomaly around the end-point of Mott boundary. A sharp jump in the LTEC values and hysteresis was observed in the area of Tg ˜ 75-77 K, what is likely explained by the transition in a glass-like state. The isotope effect in the thermal expansion is discusses, which manifested itself in a shift of the phase transitions in comparison with fully deuterated BEDT-TTF sample.

Analysis of simulated ECT signals obtained at tubesheet and tube expansion area

International Nuclear Information System (INIS)

Song, Sung Chul; Lee, Yun Tai; Jung, Hee Sung; Shin, Young Kil

2006-01-01

Steam generator(SG) tubes are expanded inside tubesheet holes by using explosive or hydraulic methods to be fixed in the tubesheet. In the tube expansion process, it is important to minimize the crevice gap between tubesheet and expanded tube. In this paper, absolute and differential signals are predicted by a numerical method for several different locations of tube expansion inside and outside the tubesheet and signal variations due to tubesheet, tube expansion and operating frequency are observed. Results show that low frequency is good for detecting tubesheet location in both types of signals and high frequency is suitable for sizing of tube diameter as well as the detection of transition region. Also learned is that the absolute signal is good for measuring tube diameter, while the differential signal is good for locating the top of tubesheet and both ends of the transition region.

Corrections to the apparent value of the cosmological constant due to local inhomogeneities

International Nuclear Information System (INIS)

Romano, Antonio Enea; Chen, Pisin

2011-01-01

Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the Universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inhomogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and true value of the cosmological constant. We establish the theoretical framework to calculate the corrections to the apparent value of the cosmological constant by modeling the local inhomogeneity with a ΛLTB solution. Our assumption to be at the center of a spherically symmetric inhomogeneous matter distribution correspond to effectively calculate the monopole contribution of the large scale inhomogeneities surrounding us, which we expect to be the dominant one, because of other observations supporting a high level of isotropy of the Universe around us. By performing a local Taylor expansion we analyze the number of independent degrees of freedom which determine the local shape of the inhomogeneity, and consider the issue of central smoothness, showing how the same correction can correspond to different inhomogeneity profiles. Contrary to previous attempts to fit data using large void models our approach is quite general. The correction to the apparent value of the cosmological constant is in fact present for local inhomogeneities of any size, and should always be taken appropriately into account both theoretically and observationally

The Thermal Expansion Of Feldspars

Science.gov (United States)

Hovis, G. L.; Medford, A.; Conlon, M.

2009-12-01

Hovis and others (1) investigated the thermal expansion of natural and synthetic AlSi3 feldspars and demonstrated that the coefficient of thermal expansion (α) decreases significantly, and linearly, with increasing room-temperature volume (VRT). In all such feldspars, therefore, chemical expansion limits thermal expansion. The scope of this work now has been broadened to include plagioclase and Ba-K feldspar crystalline solutions. X-ray powder diffraction data have been collected between room temperature and 925 °C on six plagioclase specimens ranging in composition from anorthite to oligoclase. When combined with thermal expansion data for albite (2,3,4) a steep linear trend of α as a function of VRT emerges, reflecting how small changes in composition dramatically affect expansion behavior. The thermal expansion data for five synthetic Ba-K feldspars ranging in composition from 20 to 100 mole percent celsian, combined with data for pure K-feldspar (3,4), show α-VRT relationships similar in nature to the plagioclase series, but with a slope and intercept different from the latter. Taken as a group all Al2Si2 feldspars, including anorthite and celsian from the present study along with Sr- (5) and Pb-feldspar (6) from other workers, show very limited thermal expansion that, unlike AlSi3 feldspars, has little dependence on the divalent-ion (or M-) site occupant. This apparently is due to the necessitated alternation of Al and Si in the tetrahedral sites of these minerals (7), which in turn locks the tetrahedral framework and makes the M-site occupant nearly irrelevant to expansion behavior. Indeed, in feldspar series with coupled chemical substitution it is the change away from a 1:1 Al:Si ratio that gives feldspars greater freedom to expand. Overall, the relationships among α, chemical composition, and room-temperature volume provide useful predictive tools for estimating feldspar thermal expansion and give insight into the controls of expansion behavior in

Diffusion weighted imaging and estimation of prognosis using apparent diffusion coefficient measurements in ischemic stroke

International Nuclear Information System (INIS)

Gonen, Korcan Aysun; Simsek, Mehmet Masum

2010-01-01

Objective: Estimation of the prognosis of infarction by using diffusion weighted imaging (DWI) and quantitative apparent diffusion coefficient (ADC) measurements. Methods: 23 patients having acute stroke symptoms with verified infarction in magnetic resonance imaging (MRI) were included in this study. Their MRI studies were performed between 6 and 12 h after the onset of their symptoms and were repeated on the fifth day. The infarction volumes were calculated by using DWI and the patients were divided into two groups as the ones having an expansion in the infarction area (group 1, n = 16) and the others having no expansion in the infarction area (group 2, n = 7). Quantitative ADC values were estimated. The groups were compared in terms of the ADC values on ADC maps obtained from DWI, performed during the between 6 and 12 h from the onset of the symptoms, referring to the core of the infarction (ADC IC ), ischemic penumbra (ADC P ) and the nonischemic parenchymal tissue (ADC N ). P values 3 for group 1 patients (ranging from 1.1 to 68.6) and this was found to be 40.3 cm 3 (ranging from 1.8 to 91.5) on the fifth day. For the group 2 patients these values were found to be 42.1 cm 3 (ranging from 1 to 94.7) and 41.9 (ranging from 1 to 94.7) for the same intervals respectively. A significant statistical result was failed to be demonstrated between the mean ADC IC and ADC N values (p = 0.350 and p = 0.229 respectively). However the comparison of the ADC P values between the groups was found to be highly significant (p P and ADC IC and ADC N and ADC P were compared the results proved to be statistically significant (p = 0.038 and p < 0.001 respectively). Conclusions: We believe that ADC results that would be obtained from the core and the penumbra of the infarction area will be beneficial in the estimation of the infarction prognosis and in the planning of a treatment protocol.

Simulation and Analysis of ECT Signals Obtained at Tubesheet and Tube Expansion Area

International Nuclear Information System (INIS)

Song, Sung Chul; Lee, Yun Tai; Jung, Hee Sung; Shin, Young Kil

2006-01-01

Steam generator (SG) tubes are expanded inside tubesheet holes by using explosive or hydraulic methods to be fixed in a tubesheet. In the tube expansion process, it is important to minimize the crevice gap between expanded tube and tube sheet. In this paper, absolute and differential signals are computed by a numerical method for several different locations of tube expansion inside and outside a tubesheet and signal variations due to tubesheet, tube expansion and operating frequencies are observed. Results show that low frequency is good for detecting tubesheet location in both types of signals and high frequency is suitable for sizing of tube diameter as well as the detection of transition region. Also learned is that the absolute signal is good for measuring tube diameter, while the differential signal is good for locating the top of tubesheet and both ends of the transition region. In the case of mingled anomaly with tube expansion and tubesheet, low frequency inspection is found to be useful to analyze the mixed signal

Breaking the Link between Environmental Degradation and Oil Palm Expansion: A Method for Enabling Sustainable Oil Palm Expansion

Science.gov (United States)

Smit, Hans Harmen; Meijaard, Erik; van der Laan, Carina; Mantel, Stephan; Budiman, Arif; Verweij, Pita

2013-01-01

Land degradation is a global concern. In tropical areas it primarily concerns the conversion of forest into non-forest lands and the associated losses of environmental services. Defining such degradation is not straightforward hampering effective reduction in degradation and use of already degraded lands for more productive purposes. To facilitate the processes of avoided degradation and land rehabilitation, we have developed a methodology in which we have used international environmental and social sustainability standards to determine the suitability of lands for sustainable agricultural expansion. The method was developed and tested in one of the frontiers of agricultural expansion, West Kalimantan province in Indonesia. The focus was on oil palm expansion, which is considered as a major driver for deforestation in tropical regions globally. The results suggest that substantial changes in current land-use planning are necessary for most new plantations to comply with international sustainability standards. Through visualizing options for sustainable expansion with our methodology, we demonstrate that the link between oil palm expansion and degradation can be broken. Application of the methodology with criteria and thresholds similar to ours could help the Indonesian government and the industry to achieve its pro-growth, pro-job, pro-poor and pro-environment development goals. For sustainable agricultural production, context specific guidance has to be developed in areas suitable for expansion. Our methodology can serve as a template for designing such commodity and country specific tools and deliver such guidance. PMID:24039700

Event and Apparent Horizon Finders for 3 + 1 Numerical Relativity.

Science.gov (United States)

Thornburg, Jonathan

2007-01-01

Event and apparent horizons are key diagnostics for the presence and properties of black holes. In this article I review numerical algorithms and codes for finding event and apparent horizons in numerically-computed spacetimes, focusing on calculations done using the 3 + 1 ADM formalism. The event horizon of an asymptotically-flat spacetime is the boundary between those events from which a future-pointing null geodesic can reach future null infinity and those events from which no such geodesic exists. The event horizon is a (continuous) null surface in spacetime. The event horizon is defined nonlocally in time : it is a global property of the entire spacetime and must be found in a separate post-processing phase after all (or at least the nonstationary part) of spacetime has been numerically computed. There are three basic algorithms for finding event horizons, based on integrating null geodesics forwards in time, integrating null geodesics backwards in time, and integrating null surfaces backwards in time. The last of these is generally the most efficient and accurate. In contrast to an event horizon, an apparent horizon is defined locally in time in a spacelike slice and depends only on data in that slice, so it can be (and usually is) found during the numerical computation of a spacetime. A marginally outer trapped surface (MOTS) in a slice is a smooth closed 2-surface whose future-pointing outgoing null geodesics have zero expansion Θ. An apparent horizon is then defined as a MOTS not contained in any other MOTS. The MOTS condition is a nonlinear elliptic partial differential equation (PDE) for the surface shape, containing the ADM 3-metric, its spatial derivatives, and the extrinsic curvature as coefficients. Most "apparent horizon" finders actually find MOTSs. There are a large number of apparent horizon finding algorithms, with differing trade-offs between speed, robustness, accuracy, and ease of programming. In axisymmetry, shooting algorithms work well

Radial expansion and multifragmentation

International Nuclear Information System (INIS)

Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Kerambrun, A.; Le Brun, C.; Lecolley, J.F.; Lopez, O.; Louvel, M.; Meslin, C.; Nakagawa, T.; Patry, J.P.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Yuasa-Nakagawa, K.; Wieloch, A.

1998-01-01

The light systems 36 Ar + 27 Al and 64 Zn + nat Ti were measured at several bombarding energies between ∼ 35 and 95 MeV/nucleon. It was found that the predominant part of the cross section is due to binary collisions. In this paper the focus is placed on the properties of the quasi-projectile nuclei. In the central collisions the excitation energies of the quasi-projectile reach values exceeding largely 10 MeV/nucleon. The slope of the high energy part of the distribution can give only an upper limit of the apparent temperature (the average temperature along the decay chain). The highly excited quasi-projectile may get rapidly fragmented rather than sequentially. The heavy fragments are excited and can emit light particles (n, p, d, t, 3 He, α,...) what perturbs additionally the spectrum of these particles. Concerning the expansion energy, one can determine the average kinetic energies of the product (in the quasi-projectile-framework) and compare with simulation values. To fit the experimental data an additional radial expansion energy is to be considered. The average expansion energy depends slightly on the impact parameter but it increases with E * / A, ranging from 0.4 to 1,2 MeV/nucleon for an excitation energy increasing from 7 to 10.5 MeV/nucleon. This collective radial energy seems to be independent of the fragment mass, what is possibly valid for the case of larger quasi-projectile masses. The origin of the expansion is to be determined. It may be due to a compression in the interaction zone at the initial stage of the collision, which propagates in the quasi-projectile and quasi-target, or else, may be due, simply, to the increase of thermal energy leading to a rapid fragment emission. The sequential de-excitation calculation overestimates light particle emission and consequently heavy residues, particularly, at higher excitation energies. This disagreement indicates that a sequential process can not account for the di-excitation of very hot nuclei

Assessing the contribution of binaural cues for apparent source width perception via a functional model

DEFF Research Database (Denmark)

Käsbach, Johannes; Hahmann, Manuel; May, Tobias

2016-01-01

In echoic conditions, sound sources are not perceived as point sources but appear to be expanded. The expansion in the horizontal dimension is referred to as apparent source width (ASW). To elicit this perception, the auditory system has access to fluctuations of binaural cues, the interaural time...... a statistical representation of ITDs and ILDs based on percentiles integrated over time and frequency. The model’s performance was evaluated against psychoacoustic data obtained with noise, speech and music signals in loudspeakerbased experiments. A robust model prediction of ASW was achieved using a cross...

Tetraquarks in the 1/N expansion and meson-meson resonances

Energy Technology Data Exchange (ETDEWEB)

Maiani, L. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy); Polosa, A.D. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy); CERN Theory Department, CH-1211 Geneva 23 (Switzerland); Riquer, V. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy)

2016-06-27

Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.

Tetraquarks in the 1/N expansion and meson-meson resonances

International Nuclear Information System (INIS)

Maiani, L.; Polosa, A.D.; Riquer, V.

2016-01-01

Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.

Reevaluating Suitability Estimates Based on Dynamics of Cropland Expansion in the Brazilian Amazon

Science.gov (United States)

Morton, Douglas C.; Noojipady, Praveen; Macedo, Marcia M.; Victoria, Daniel C.; Bolfe, Edson L.

2016-01-01

Agricultural suitability maps are a key input for land use zoning and projections of cropland expansion. Suitability assessments typically consider edaphic conditions, climate, crop characteristics, and sometimes incorporate accessibility to transportation and market infrastructure. However, correct weighting among these disparate factors is challenging, given rapid development of new crop varieties, irrigation, and road networks, as well as changing global demand for agricultural commodities. Here, we compared three independent assessments of cropland suitability to spatial and temporal dynamics of agricultural expansion in the Brazilian state of Mato Grosso during 2001 2012. We found that areas of recent cropland expansion identified using satellite data were generally designated as low to moderate suitability for rainfed crop production. Our analysis highlighted the abrupt nature of suitability boundaries, rather than smooth gradients of agricultural potential, with little additional cropland expansion beyond the extent of the flattest areas (0-2% slope). Satellite-based estimates of the interannual variability in the use of existing crop areas also provided an alternate means to assess suitability. On average, cropland areas in the Cerrado biome had higher utilization (84%) than croplands in the Amazon region of northern Mato Grosso (74%). Areas of more recent expansion had lower utilization than croplands established before 2002, providing empirical evidence for lower suitability or alternative management strategies (e.g., pasture soya rotations) for lands undergoing more recent land use transitions. This unplanted reserve constitutes a large area of potentially available cropland (PAC)without further expansion, within the management limits imposed for pest management and fallow cycles. Using two key constraints on future cropland expansion, slope and restrictions on further deforestation of Amazon or Cerrado vegetation, we found little available flat land for

Event and Apparent Horizon Finders for 3+1 Numerical Relativity

Directory of Open Access Journals (Sweden)

Thornburg Jonathan

2007-06-01

Full Text Available Event and apparent horizons are key diagnostics for the presence and properties of black holes. In this article I review numerical algorithms and codes for finding event and apparent horizons in numerically-computed spacetimes, focusing on calculations done using the 3+1 ADM formalism. The event horizon of an asymptotically-flat spacetime is the boundary between those events from which a future-pointing null geodesic can reach future null infinity and those events from which no such geodesic exists. The event horizon is a (continuous null surface in spacetime. The event horizon is defined nonlocally in time: it is a global property of the entire spacetime and must be found in a separate post-processing phase after all (or at least the nonstationary part of spacetime has been numerically computed.There are three basic algorithms for finding event horizons, based on integrating null geodesics forwards in time, integrating null geodesics backwards in time, and integrating null surfaces backwards in time. The last of these is generally the most efficient and accurate.In contrast to an event horizon, an apparent horizon is defined locally in time in a spacelike slice and depends only on data in that slice, so it can be (and usually is found during the numerical computation of a spacetime. A marginally outer trapped surface (MOTS in a slice is a smooth closed 2-surface whose future-pointing outgoing null geodesics have zero expansion Theta. An apparent horizon is then defined as a MOTS not contained in any other MOTS. The MOTS condition is a nonlinear elliptic partial differential equation (PDE for the surface shape, containing the ADM 3-metric, its spatial derivatives, and the extrinsic curvature as coefficients. Most “apparent horizon” finders actually find MOTSs.There are a large number of apparent horizon finding algorithms, with differing trade-offs between speed, robustness, accuracy, and ease of programming. In axisymmetry, shooting

Integrating agricultural expansion into conservation biogeography: conflicts and priorities

Directory of Open Access Journals (Sweden)

Ricardo Dobrovolski

2014-06-01

Full Text Available Increasing food production without compromising biodiversity is one of the great challenges for humanity. The aims of my thesis were to define spatial priorities for biodiversity conservation and to evaluate conservation conflicts considering agricultural expansion in the 21st century. I also tested the effect of globalizing conservation efforts on both food production and biodiversity conservation. I found spatial conflicts between biodiversity conservation and agricultural expansion. However, incorporating agricultural expansion data into the spatial prioritization process can significantly alleviate conservation conflicts, by reducing spatial correlation between the areas under high impact of agriculture and the priority areas for conservation. Moreover, developing conservation blueprints at the global scale, instead of the usual approach based on national boundaries, can benefit both food production and biodiversity. Based on these findings I conclude that the incorporation of agricultural expansion as a key component for defining global conservation strategies should be added to the list of solutions for our cultivated planet.

Cognitive and clinical characteristics of patients with amyotrophic lateral sclerosis carrying a C9orf72 repeat expansion: a population-based cohort study.

LENUS (Irish Health Repository)

Byrne, Susan

2012-03-01

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of upper and lower motor neurons, associated with frontotemporal dementia (FTD) in about 14% of incident cases. We assessed the frequency of the recently identified C9orf72 repeat expansion in familial and apparently sporadic cases of ALS and characterised the cognitive and clinical phenotype of patients with this expansion.

Origami structures for tunable thermal expansion

Science.gov (United States)

Boatti, Elisa; Bertoldi, Katia

Materials with engineered thermal expansion, capable of achieving targeted and extreme area/volume changes in response to variations in temperature, are important for a number of aerospace, optical, energy, and microelectronic applications. While most of the proposed structures with tunable coefficient of thermal expansion consist of bi-material 2D or 3D lattices, here we propose a periodic metastructure based on a bilayer Miura-Ori origami fold. We combine experiments and simulations to demonstrate that by tuning the geometrical and mechanical parameters an extremely broad range of thermal expansion coefficients can be obtained, spanning both negative and positive values. Additionally, the thermal properties along different directions can be adjusted independently. Differently from all previously reported systems, the proposed structure is non-porous.

[Spatiotemporal differentiation of construction land expansion in a typical town of south Jiangsu Province].

Science.gov (United States)

Zhou, Rui; Li, Yue-hui; Hu, Yuan-man; Su, Hai-long; Wang, Jin-nian

2011-03-01

Choosing Xinzhuang Town in south Jiangsu Province as study area, and by using 1980, 1991, 2001, and 2009 high-resolution remote sensing images and GIS spatial analysis technology, an integrated expansion degree index model was established based on the existing indicators of construction land expansion, and the general and spatiotemporal differentiation characteristics of construction land expansion in the Town in three time periods of 1980-2009 were quantitatively analyzed. In 1980-2009, with the acceleration of rural urbanization and industrialization, the area of construction land in the Town increased significantly by 19.24 km2, and especially in 2001-2009, the expanded area, expanded contribution rate, and expansion intensity reached the maximum. The construction land expansion had an obvious spatial differentiation characteristic. In 1980-1991, the newly increased construction land mainly concentrated in town area. After 1991, the focus of construction land gradually spread to the villages with developed industries. Most of the increased construction lands were converted from paddy field and dry land, accounting for 88.1% of the total increased area, while the contribution from other land types was relatively small.

Pressure-induced referred pain areas are more expansive in individuals with a recovered fracture

DEFF Research Database (Denmark)

Doménech-García, Víctor; Skuli Palsson, Thorvaldur; Boudreau, Shellie Ann

2018-01-01

the shoulder region was induced by a 60-s pressure stimulation (PPT+20%) at the infraspinatus muscle and recorded on an electronic body chart. Following Day-0 assessments, delayed onset muscle soreness (DOMS) was induced to challenge the pain systems by exercising the external rotators of the recovered...... a shoulder fracture and 20 age/gender matched controls participated in two experimental sessions (Day-0, Day-1) separated by 24 hours. On both days, pressure pain thresholds (PPTs) were measured bilaterally at infraspinatus, supraspinatus, trapezius, and gastrocnemius muscles. Referred pain towards....../dominant shoulder. The size of pressure-induced pain referral on Day-0 did not differ between groups although there was a tendency for a smaller referred pain area in recovered group. PPTs at the infraspinatus muscle on the DOMS side was reduced on Day-1 in both groups (P=0.03). An expansion of pressure...

Cropland expansion in Brazil, 2000 to 2014

Science.gov (United States)

Zalles, V.; Hansen, M.; Potapov, P.; Stehman, S. V.; Tyukavina, A.; Pickens, A. H.; Okpa, C.; Aguilar, R.; John, N.; Chavez, S.

2017-12-01

Brazil has become a global leader in the production of commodity row crops such as soybean, sugarcane, cotton, and corn. Here, we employ 30m spatial resolution Landsat data to estimate cropland extent in the year 2000 and its subsequent expansion through 2014. A probability-based sample of reference data allows us to report unbiased estimates of national, biome, and state-scale area of crop expansion with associated uncertainties. We find an increase in Brazilian cropland extent from 26.0 Mha in 2000 to 46.1 Mha in 2014. The cropland frontier states of Maranhao, Tocantins, Piaui, Bahia (MATOPIBA), Mato Grosso, Mato Grosso do Sul, and Para all more than doubled in cropland extent. The states of Goias, Minas Gerais and Sao Paulo experienced >50% increases. The vast majority of expansion, 79%, occurred on repurposed pasture lands, and 20% from the conversion of natural vegetation. Area of converted Cerrado savannas was nearly 2.5 times that of Amazon forests, and accounted for over half of new cropland in MATOPIBA. Spatio-temporal dynamics of cropland expansion are reflected in market conditions, land use policies, and other factors. Continued extensification of cropland is a viable option across Brazil with attendant benefits for and challenges to development.

Age-related mutations associated with clonal hematopoietic expansion and malignancies.

Science.gov (United States)

Xie, Mingchao; Lu, Charles; Wang, Jiayin; McLellan, Michael D; Johnson, Kimberly J; Wendl, Michael C; McMichael, Joshua F; Schmidt, Heather K; Yellapantula, Venkata; Miller, Christopher A; Ozenberger, Bradley A; Welch, John S; Link, Daniel C; Walter, Matthew J; Mardis, Elaine R; Dipersio, John F; Chen, Feng; Wilson, Richard K; Ley, Timothy J; Ding, Li

2014-12-01

Several genetic alterations characteristic of leukemia and lymphoma have been detected in the blood of individuals without apparent hematological malignancies. The Cancer Genome Atlas (TCGA) provides a unique resource for comprehensive discovery of mutations and genes in blood that may contribute to the clonal expansion of hematopoietic stem/progenitor cells. Here, we analyzed blood-derived sequence data from 2,728 individuals from TCGA and discovered 77 blood-specific mutations in cancer-associated genes, the majority being associated with advanced age. Remarkably, 83% of these mutations were from 19 leukemia and/or lymphoma-associated genes, and nine were recurrently mutated (DNMT3A, TET2, JAK2, ASXL1, TP53, GNAS, PPM1D, BCORL1 and SF3B1). We identified 14 additional mutations in a very small fraction of blood cells, possibly representing the earliest stages of clonal expansion in hematopoietic stem cells. Comparison of these findings to mutations in hematological malignancies identified several recurrently mutated genes that may be disease initiators. Our analyses show that the blood cells of more than 2% of individuals (5-6% of people older than 70 years) contain mutations that may represent premalignant events that cause clonal hematopoietic expansion.

Futures of global urban expansion: uncertainties and implications for biodiversity conservation

Science.gov (United States)

Güneralp, B.; Seto, K. C.

2013-03-01

Urbanization will place significant pressures on biodiversity across the world. However, there are large uncertainties in the amount and location of future urbanization, particularly urban land expansion. Here, we present a global analysis of urban extent circa 2000 and probabilistic forecasts of urban expansion for 2030 near protected areas and in biodiversity hotspots. We estimate that the amount of urban land within 50 km of all protected area boundaries will increase from 450 000 km2 circa 2000 to 1440 000 ± 65 000 km2 in 2030. Our analysis shows that protected areas around the world will experience significant increases in urban land within 50 km of their boundaries. China will experience the largest increase in urban land near protected areas with 304 000 ± 33 000 km2 of new urban land to be developed within 50 km of protected area boundaries. The largest urban expansion in biodiversity hotspots, over 100 000 ± 25 000 km2, is forecasted to occur in South America. Uncertainties in the forecasts of the amount and location of urban land expansion reflect uncertainties in their underlying drivers including urban population and economic growth. The forecasts point to the need to reconcile urban development and biodiversity conservation strategies.

Futures of global urban expansion: uncertainties and implications for biodiversity conservation

International Nuclear Information System (INIS)

Güneralp, B; Seto, K C

2013-01-01

Urbanization will place significant pressures on biodiversity across the world. However, there are large uncertainties in the amount and location of future urbanization, particularly urban land expansion. Here, we present a global analysis of urban extent circa 2000 and probabilistic forecasts of urban expansion for 2030 near protected areas and in biodiversity hotspots. We estimate that the amount of urban land within 50 km of all protected area boundaries will increase from 450 000 km 2 circa 2000 to 1440 000 ± 65 000 km 2 in 2030. Our analysis shows that protected areas around the world will experience significant increases in urban land within 50 km of their boundaries. China will experience the largest increase in urban land near protected areas with 304 000 ± 33 000 km 2 of new urban land to be developed within 50 km of protected area boundaries. The largest urban expansion in biodiversity hotspots, over 100 000 ± 25 000 km 2 , is forecasted to occur in South America. Uncertainties in the forecasts of the amount and location of urban land expansion reflect uncertainties in their underlying drivers including urban population and economic growth. The forecasts point to the need to reconcile urban development and biodiversity conservation strategies. (letter)

Subducted bathymetric features linked to variations in earthquake apparent stress along the northern Japan Trench

Science.gov (United States)

Moyer, P. A.; Bilek, S. L.; Phillips, W. S.

2010-12-01

Ocean floor bathymetric features such as seamounts and ridges are thought to influence the earthquake rupture process when they enter the subduction zone by causing changes in frictional conditions along the megathrust contact between the subducting and overriding plates. Once subducted, these features have been described as localized areas of heterogeneous plate coupling, with some controversy over whether these features cause an increase or decrease in interplate coupling. Along the northern Japan Trench, a number of bathymetric features, such as horst and graben structures and seamounts, enter the subduction zone where they may vary earthquake behavior. Using seismic coda waves, scattered energy following the direct wave arrivals, we compute apparent stress (a measure of stress drop proportional to radiated seismic energy that has been tied to the strength of the fault interface contact) for 329 intermediate magnitude (3.2 earthquake spectra for path and site effects and compute apparent stress using the seismic moment and corner frequency determined from the spectra. Preliminary results indicate apparent stress values between 0.3 - 22.6 MPa for events over a depth range of 2 - 55 km, similar to those found in other studies of the region although within a different depth range, with variations both along-strike and downdip. Off the Sanriku Coast, horst and graben structures enter the Japan Trench in an area where a large number of earthquakes occur at shallow (< 30 km) depth. These shallow events have a mean apparent stress of 1.2 MPa (range 0.3 - 3.8 MPa) which is approximately 2 times lower then the mean apparent stress for other events along the northern portion of this margin in the same shallow depth range. The relatively low apparent stress for events related to subducting horst and graben structures suggests weak interplate coupling between the subducting and overriding plates due to small, irregular contact zones with these features at depth. This is in

Primary visual cortex activity along the apparent-motion trace reflects illusory perception.

Directory of Open Access Journals (Sweden)

Lars Muckli

2005-08-01

Full Text Available The illusion of apparent motion can be induced when visual stimuli are successively presented at different locations. It has been shown in previous studies that motion-sensitive regions in extrastriate cortex are relevant for the processing of apparent motion, but it is unclear whether primary visual cortex (V1 is also involved in the representation of the illusory motion path. We investigated, in human subjects, apparent-motion-related activity in patches of V1 representing locations along the path of illusory stimulus motion using functional magnetic resonance imaging. Here we show that apparent motion caused a blood-oxygenation-level-dependent response along the V1 representations of the apparent-motion path, including regions that were not directly activated by the apparent-motion-inducing stimuli. This response was unaltered when participants had to perform an attention-demanding task that diverted their attention away from the stimulus. With a bistable motion quartet, we confirmed that the activity was related to the conscious perception of movement. Our data suggest that V1 is part of the network that represents the illusory path of apparent motion. The activation in V1 can be explained either by lateral interactions within V1 or by feedback mechanisms from higher visual areas, especially the motion-sensitive human MT/V5 complex.

Expansion of the uranium mines in the Elliot Lake area

International Nuclear Information System (INIS)

1979-11-01

This report forms the response of the government of Ontario to an earlier report issued by an Envrionmental Assessment Board. Specifically, the report deals with the rapid growth of the town of Elliot Lake due to expansion of several uranium mine-mill operations. Rapid growth of small communities presents considerable problems in providing housing, essential services, and educational facilities. Several specific actions taken by the government to help the town cope with rapid growth are presented. (O.T.)

Tissue Expansion Using Hyaluronic Acid Filler for Single-Stage Ear Reconstruction: A Novel Concept for Difficult Areas.

Science.gov (United States)

Inbal, Amir; Lemelman, Benjamin T; Millet, Eran; Greensmith, Andrew

2017-10-16

Auricular reconstruction is one of the most challenging procedures in plastic surgery. An adequate skin envelope is essential for cartilage framework coverage, yet few good options exist without additional surgery. We propose a novel method for minimally invasive tissue expansion, using hyaluronic acid (HA) filler to allow for single-stage ear reconstruction. To introduce the novel concept of HA filler for tissue expansion in ear reconstruction, and as an alternative to traditional expansion techniques. Macrolane is a large particle HA gel developed for large volume restoration. Expansion of the non-hair-bearing mastoid skin was performed in our clinic weekly or every other week. Final expansion was completed one week prior to reconstructive surgery. Tissue from one patient's expanded pocket was sent for histological analysis. Ten patients underwent single-stage auricular reconstruction with preoperative expansion. Injection sessions ranged from 7 to 13 (mean, 9.7). Mean injected volume per session was 2.03 mL per patient, for an average total of 19.8 mL (range, 14.5-30 mL). There were no major complications. One minor complication required removal of exposed wire from the antihelix in the office. Hematoxylin and eosin stain revealed similar histology to that seen with traditional expanders. This novel expansion technique using serial HA injections allowed for optimized skin coverage in single-stage ear reconstruction. The concept of tissue expansion using HA filler is a new frontier for research that may be applicable to other arenas of reconstruction. 4. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

High-yield oil palm expansion spares land at the expense of forests in the Peruvian Amazon

International Nuclear Information System (INIS)

Gutiérrez-Vélez, Víctor H; DeFries, Ruth; Uriarte, María; Lim, Yili; Pinedo-Vásquez, Miguel; Padoch, Christine; Baethgen, Walter; Fernandes, Katia

2011-01-01

High-yield agriculture potentially reduces pressure on forests by requiring less land to increase production. Using satellite and field data, we assessed the area deforested by industrial-scale high-yield oil palm expansion in the Peruvian Amazon from 2000 to 2010, finding that 72% of new plantations expanded into forested areas. In a focus area in the Ucayali region, we assessed deforestation for high- and smallholder low-yield oil palm plantations. Low-yield plantations accounted for most expansion overall (80%), but only 30% of their expansion involved forest conversion, contrasting with 75% for high-yield expansion. High-yield expansion minimized the total area required to achieve production but counter-intuitively at higher expense to forests than low-yield plantations. The results show that high-yield agriculture is an important but insufficient strategy to reduce pressure on forests. We suggest that high-yield agriculture can be effective in sparing forests only if coupled with incentives for agricultural expansion into already cleared lands.

216-B-3 expansion ponds closure plan

International Nuclear Information System (INIS)

1994-10-01

This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA

216-B-3 expansion ponds closure plan

Energy Technology Data Exchange (ETDEWEB)

1994-10-01

This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA.

Principles of Thermal Expansion in Feldspars

Science.gov (United States)

Hovis, Guy; Medford, Aaron; Conlon, Maricate; Tether, Allison; Romanoski, Anthony

2010-05-01

Following the recent thermal expansion work of Hovis et al. (1) on AlSi3 feldspars, we have investigated the thermal expansion of plagioclase, Ba-K, and Ca-K feldspar crystalline solutions. X-ray powder diffraction data were collected between room temperature and 925 °C on six natural plagioclase specimens ranging in composition from anorthite to oligoclase, the K-exchanged equivalents of these plagioclase specimens, and five synthetic Ba-K feldspars with compositions ranging from 25 to 99 mol % BaAl2Si2O8. The resulting thermal expansion coefficients (α) for volume have been combined with earlier results for end-member Na- and K-feldspars (2,3). Unlike AlSi3 feldspars, Al2Si2 feldspars, including anorthite and celsian from the present study plus Sr- and Pb-feldspar from other workers (4,5), show essentially constant and very limited thermal expansion, regardless of divalent cation size. In the context of structures where the Lowenstein rule (6) requires Al and Si to alternate among tetrahedra, the proximity of bridging Al-O-Si oxygen ions to divalent neighbors (ranging from 0 to 2) produces short Ca-O (or Ba-O) bonds (7,8) that apparently are the result of local charge-balance requirements (9). Gibbs et al. (10) suggest that short bonds such as these have a partially covalent character. This in turn stiffens the structure. Thus, for feldspar series with coupled substitution the change away from a purely divalent M-site occupant gives the substituting (less strongly bonded) monovalent cations increasingly greater influence on thermal expansion. Overall, then, thermal expansion in the feldspar system is well represented on a plot of α against room-temperature volume, where one sees a quadrilateral bounded by data for (A) AlSi3 feldspars whose expansion behavior is controlled largely by the size of the monovalent alkali-site occupant, (B) Al2Si2 feldspars whose expansion is uniformly limited by partially-covalent bonds between divalent M-site occupants and

Expansion of Tubular with Elastomers in Multilateral Wells

Directory of Open Access Journals (Sweden)

Md Velden

2013-06-01

Full Text Available The use of solid expandable tubular technology during the last decade has focused on solving many challenges in well drilling and delivery including zonal isolation, deep drilling, conservation of hole sizes, etc. not only as pioneered solution but also providing cost effective and long lasting solutions. Concurrently, the technology was extended for construction of multilateral in typical wells. The process of horizontal tubular expansion is similar to the vertical expansion of expandable tubular in down-hole environment with the addition of uniformly distributed force due to its weight. The expansion is targeted to increase its diameter such that post expansion characteristics remain within allowable limits. In this study a typical expandable tubular of 57.15 mm outer diameter and 6.35 mm wall thickness was used with two different elastomer seals of 5 and 7 mm thickness placed at equal spacing of 200 mm. The developed stress contours during expansion process clearly showed the high stress areas in the vicinity of expansion region which lies around the mandrel. These high stresses may result in excessive wear of the mandrel. It was also found out that the drawing force increases as the mandrel angle, expansion ratio, and friction coefficient increases. A mandrel angle of 20o  requires minimum expansion force and can be considered as an optimum geometrical parameter to lower the power required for expansion.

NICER Detection of Strong Photospheric Expansion during a Thermonuclear X-Ray Burst from 4U 1820–30

DEFF Research Database (Denmark)

Keek, L.; Arzoumanian, Z.; Chakrabarty, D.

2018-01-01

. Radiation pressure pushed the photosphere out to ∼200 km, while the blackbody temperature dropped to 0.45 keV. Previous observations of similar bursts were performed with instruments that are sensitive only above 3 keV, and the burst signal was weak at low temperatures. NICER's 0.2–12 keV passband enables...... the first complete detailed observation of strong expansion bursts. The strong expansion lasted only 0.6 s, and was followed by moderate expansion with a 20 km apparent radius, before the photosphere finally settled back down at 3 s after the burst onset. In addition to thermal emission from the neutron...

Territorial expansion and primary state formation.

Science.gov (United States)

Spencer, Charles S

2010-04-20

A major research problem in anthropology is the origin of the state and its bureaucratic form of governance. Of particular importance for evaluating theories of state origins are cases of primary state formation, whereby a first-generation state evolves without contact with any preexisting states. A general model of this process, the territorial-expansion model, is presented and assessed with archaeological data from six areas where primary states emerged in antiquity: Mesoamerica, Peru, Egypt, Mesopotamia, the Indus Valley, and China. In each case, the evidence shows a close correspondence in time between the first appearance of state institutions and the earliest expansion of the state's political-economic control to regions lying more than a day's round-trip from the capital. Although additional research will add detail and clarity to the empirical record, the results to date are consistent with the territorial-expansion model, which argues that the success of such long-distance expansion not only demanded the bureaucratization of central authority but also helped provide the resources necessary to underwrite this administrative transformation.

Avian influenza virus infection in apparently healthy domestic birds in Sokoto, Nigeria

Directory of Open Access Journals (Sweden)

Innocent Okwundu Nwankwo

2012-09-01

Full Text Available The study was conducted among apparently healthy birds brought from different local government areas, neighbouring states and across international boundaries to the Sokoto central live bird market between October 2008 and March 2009. Tracheal and cloacal swabs were collected from 221 apparently healthy birds comprising 182 chickens, 3 turkeys, 11 guineafowl, 17 ducks and 8 pigeons. These samples were analysed using nested polymerase chain reaction (nPCR to check for the presence of avian influenza virus. An overall prevalence of 1.4% (3 positive cases was detected with two cases observed in chickens and one in a pigeon. The findings indicate the circulation of avian influenza in the study area. This raises concern for human and animal health due to zoonotic and economic implications of this virus.

Stability Evaluation of Buildings in Urban Area Using Persistent Scatterer Interfometry -Focused on Thermal Expansion Effect

Science.gov (United States)

Choi, J. H.; Kim, S. W.; Won, J. S.

2017-12-01

The objective of this study is monitoring and evaluating the stability of buildings in Seoul, Korea. This study includes both algorithm development and application to a case study. The development focuses on improving the PSI approach for discriminating various geophysical phase components and separating them from the target displacement phase. A thermal expansion is one of the key components that make it difficult for precise displacement measurement. The core idea is to optimize the thermal expansion factor using air temperature data and to model the corresponding phase by fitting the residual phase. We used TerraSAR-X SAR data acquired over two years from 2011 to 2013 in Seoul, Korea. The temperature fluctuation according to seasons is considerably high in Seoul, Korea. Other problem is the highly-developed skyscrapers in Seoul, which seriously contribute to DEM errors. To avoid a high computational burden and unstable solution of the nonlinear equation due to unknown parameters (a thermal expansion parameter as well as two conventional parameters: linear velocity and DEM errors), we separate a phase model into two main steps as follows. First, multi-baseline pairs with very short time interval in which deformation components and thermal expansion can be negligible were used to estimate DEM errors first. Second, single-baseline pairs were used to estimate two remaining parameters, linear deformation rate and thermal expansion. The thermal expansion of buildings closely correlate with the seasonal temperature fluctuation. Figure 1 shows deformation patterns of two selected buildings in Seoul. In the figures of left column (Figure 1), it is difficult to observe the true ground subsidence due to a large cyclic pattern caused by thermal dilation of the buildings. The thermal dilation often mis-leads the results into wrong conclusions. After the correction by the proposed method, true ground subsidence was able to be precisely measured as in the bottom right figure

Higher US crop prices trigger little area expansion so marginal land for biofuel crops is limited

International Nuclear Information System (INIS)

Swinton, Scott M.; Babcock, Bruce A.; James, Laura K.; Bandaru, Varaprasad

2011-01-01

By expanding energy biomass production on marginal lands that are not currently used for crops, food prices increase and indirect climate change effects can be mitigated. Studies of the availability of marginal lands for dedicated bioenergy crops have focused on biophysical land traits, ignoring the human role in decisions to convert marginal land to bioenergy crops. Recent history offers insights about farmer willingness to put non-crop land into crop production. The 2006-09 leap in field crop prices and the attendant 64% gain in typical profitability led to only a 2% increase in crop planted area, mostly in the prairie states. At this rate, a doubling of expected profitability from biomass crops would expand cropland supply by only 3.2%. Yet targets for cellulosic ethanol production in the US Energy Independence and Security Act imply boosting US planted area by 10% or more with perennial biomass crops. Given landowner reluctance to expand crop area with familiar crops in the short run, large scale expansion of the area in dedicated bioenergy crops will likely be difficult and costly to achieve. - Highlights: → Biofuel crops on cropland can displace food crops, reducing food supply and triggering indirect land use. → Growing biofuel crops on non-crop marginal land avoids these problems. → But US farmers expanded cropland by only 2% when crop profitability jumped 64% during 2006-09. → So medium-term availability of marginal lands for biofuel crops is limited and costly.

Urban expansion simulation and the spatio-temporal changes of ecosystem services, a case study in Atlanta Metropolitan area, USA.

Science.gov (United States)

Sun, Xiao; Crittenden, John C; Li, Feng; Lu, Zhongming; Dou, Xiaolin

2018-05-01

Urban expansion can lead to land use changes and, hence, threatens the ecosystems. Understanding the effects of urbanization on ecosystem services (ESs) can provide scientific guidance for land use planning and the protection of ESs. We established a framework to assess the spatial distributions of ESs based on land use changes in the Atlanta Metropolitan area (AMA) from 1985 to 2012. A new comprehensive ecosystem service (CES) index was developed to reflect the comprehensive level of ESs. Associated with the influential factors, we simulated the business as usual scenario in 2030. Four alternative scenarios, including more compact growth (MCG), riparian vegetation buffer (RVB), soil conservation (SC), and combined development (CD) scenarios were developed to explore the optimal land use strategies which can enhance the ESs. The results showed that forest and wetland had the greatest decreases, while low and high intensity built-up lands had the greatest increases. The values of CES and most of ESs decreased significantly due to the sprawling expansion of built-up land. The scenario analysis revealed that the CD scenario performs best in CES value, while it performs the worst in food supply. Compared with the RVB and SC scenarios, MCG scenario is a more optimal land use strategy to enhance the ESs without at the expense of food supply. To integrate multiple ESs into land use planning and decision making, corresponding land management policies and ecological engineering measures should be implemented to enhance: (1) the water yield and water purification in urban core counties, (2) the carbon storage, habitat quality, and recreational opportunity in counties around the core area, and (3) the soil conservation and food supply in surrounding suburban counties. The land use strategies and ecological engineering measures in this study can provide references for enhancing the ESs in the AMA and other metropolitan areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Abandonment and expansion of arable land in Europe

NARCIS (Netherlands)

Hatna, E.; Bakker, M.M.

2011-01-01

Abandonment of arable land is often assumed to happen mostly in marginal areas where the conditions for arable cultivation are relatively unfavorable, whereas arable expansion is expected to occur mostly in areas with favorable conditions. This assumption, used in many land-use change forecasts, was

[Ecological suitability assessment and optimization of urban land expansion space in Guiyang City].

Science.gov (United States)

Qiu, Cong-hao; Li, Yang-bing; Feng, Yuan-song

2015-09-01

Based on the case study of Guiyang City, the minimum cumulative resistance model integrating construction land source, ecological rigid constraints and ecological function type resistance factor, was built by use of cost-distance analysis of urban spatial expansion resistance value through ArcGIS 9.3 software in this paper. Then, the ecological resistance of city spatial expansion of Guiyang from 2010 was simulated dynamically and the ecological suitability classification of city spatial expansion was assessed. According to the conflict between the newly increased city construction land in 2014 and its ecological suitability, the unreasonable city land spatial allocation was discussed also. The results showed that the ecological suitability zonation and the city expansion in the study area were basically consistent during 2010-2014, but the conflict between the new city construction and its land ecological suitability was more serious. The ecological conflict area accounted for 58.2% of the new city construction sites, 35.4% of which happened in the ecological control area, 13.9% in the limited development area and 8.9% in the prohibition development area. The intensification of ecological land use conflict would impair the ecological service function and ecological safety, so this paper put forward the city spatial expansion optimal path to preserve the ecological land and improve the construction land space pattern of Guiyang City so as to ensure its ecological safety.

Irreversible thermodynamics of dark energy on the entropy-corrected apparent horizon

Energy Technology Data Exchange (ETDEWEB)

Karami, K; Sahraei, N [Department of Physics, University of Kurdistan, Pasdaran Street, Sanandaj (Iran, Islamic Republic of); Jamil, M, E-mail: KKarami@uok.ac.i, E-mail: mjamil@camp.nust.edu.p [Center for Advanced Mathematics and Physics (CAMP), National University of Sciences and Technology (NUST), Islamabad (Pakistan)

2010-10-15

We study the irreversible (non-equilibrium) thermodynamics of the Friedmann-Robertson-Walker (FRW) universe containing only dark energy. Using the modified entropy-area relation that is motivated by loop quantum gravity, we calculate the entropy-corrected form of the apparent horizon of the FRW universe.

Assessing the MODIS crop detection algorithm for soybean crop area mapping and expansion in the Mato Grosso state, Brazil.

Science.gov (United States)

Gusso, Anibal; Arvor, Damien; Ducati, Jorge Ricardo; Veronez, Mauricio Roberto; da Silveira, Luiz Gonzaga

2014-01-01

Estimations of crop area were made based on the temporal profiles of the Enhanced Vegetation Index (EVI) obtained from moderate resolution imaging spectroradiometer (MODIS) images. Evaluation of the ability of the MODIS crop detection algorithm (MCDA) to estimate soybean crop areas was performed for fields in the Mato Grosso state, Brazil. Using the MCDA approach, soybean crop area estimations can be provided for December (first forecast) using images from the sowing period and for February (second forecast) using images from the sowing period and the maximum crop development period. The area estimates were compared to official agricultural statistics from the Brazilian Institute of Geography and Statistics (IBGE) and from the National Company of Food Supply (CONAB) at different crop levels from 2000/2001 to 2010/2011. At the municipality level, the estimates were highly correlated, with R (2) = 0.97 and RMSD = 13,142 ha. The MCDA was validated using field campaign data from the 2006/2007 crop year. The overall map accuracy was 88.25%, and the Kappa Index of Agreement was 0.765. By using pre-defined parameters, MCDA is able to provide the evolution of annual soybean maps, forecast of soybean cropping areas, and the crop area expansion in the Mato Grosso state.

Apparent clusters of childhood lymphoid malignancy in Northern England

International Nuclear Information System (INIS)

Craft, A.W.; Openshaw, S.; Birch, J.

1984-01-01

The authors have reanalysed their previous data on the incidence of childhood malignancy in the North of England by very small geographical areas. Seascale, which ranks first by Poisson probability for all lymphoid malignancies is the village closest to the Sellafield plant. However, it is not unique in the region; nor are wards of apparent excess confined to coastal areas of Cumbria. The highest rate of lymphoid malignancies is in Whittingham, a village in north Northumberland. For other varieties of childhood cancer, there is a similar spread of 'Highly ranked', but different, wards throughout the region. (U.K.)

Biodiversity at risk under future cropland expansion and intensification.

Science.gov (United States)

Kehoe, Laura; Romero-Muñoz, Alfredo; Polaina, Ester; Estes, Lyndon; Kreft, Holger; Kuemmerle, Tobias

2017-08-01

Agriculture is the leading driver of biodiversity loss. However, its future impact on biodiversity remains unclear, especially because agricultural intensification is often neglected, and high path-dependency is assumed when forecasting agricultural development-although the past suggests that shock events leading to considerable agricultural change occur frequently. Here, we investigate the possible impacts on biodiversity of pathways of expansion and intensification. Our pathways are not built to reach equivalent production targets, and therefore they should not be directly compared; they instead highlight areas at risk of high biodiversity loss across the entire option space of possible agricultural change. Based on an extensive database of biodiversity responses to agriculture, we find 30% of species richness and 31% of species abundances potentially lost because of agricultural expansion across the Amazon and Afrotropics. Only 21% of high-risk expansion areas in the Afrotropics overlap with protected areas (compared with 43% of the Neotropics). Areas at risk of biodiversity loss from intensification are found in India, Eastern Europe and the Afromontane region (7% species richness, 13% abundance loss). Many high-risk regions are not adequately covered by conservation prioritization schemes, and have low national conservation spending and high agricultural growth. Considering rising agricultural demand, we highlight areas where timely land-use planning may proactively mitigate biodiversity loss.

Development of complex simulation suite 'VEB' and application area expansion - 15326

International Nuclear Information System (INIS)

Obraztsov, E.; Kapista, D.; Kremnev, I.; Korokhov, T.; Kukhtevich, V.; Bezlepkin, V.

2015-01-01

Complex simulation suite 'Virtual Unit of NPP' (CSS 'VEB') is a set of connected software tools and computer codes that allow the simulation of various physical processes occurring in a power nuclear reactor (initially VVER - pressurized water reactor). A coupled computational model developed by means of CSS 'VEB' is based on a specific design and called an NPP Virtual Power Unit (VPU). And in November 2012 a pilot version of the Leningrad NPP-2 VPU (NPP-2006 design with water-cooled power reactor) successfully passed acceptance tests. The paper presents further development of CSS 'VEB' and application area expansion both on new tasks such as VPU calculations for the Probability Safety Analysis (PSA) and all modeling of other NPP types, like sodium-cooled reactor (that means a possibility to create a VPU not only for NPP with PWR). In the first part of this paper we will recall the basic idea and concept of CSS 'VEB' and VPU. Then we will describe the main components of CSS 'VEB' and their improvements. In the last part we will briefly describe the broadening of VPU uses

Winter fidelity and apparent survival of lesser snow goose populations in the Pacific flyway

Science.gov (United States)

Williams, C.K.; Samuel, M.D.; Baranyuk, Vasily V.; Cooch, E.G.; Kraege, Donald K.

2008-01-01

The Beringia region of the Arctic contains 2 colonies of lesser snow geese (Chen caerulescens caerulescens) breeding on Wrangel Island, Russia, and Banks Island, Canada, and wintering in North America. The Wrangel Island population is composed of 2 subpopulations from a sympatric breeding colony but separate wintering areas, whereas the Banks Island population shares a sympatric wintering area in California, USA, with one of the Wrangel Island subpopulations. The Wrangel Island colony represents the last major snow goose population in Russia and has fluctuated considerably since 1970, whereas the Banks Island population has more than doubled. The reasons for these changes are unclear, but hypotheses include independent population demographics (survival and recruitment) and immigration and emigration among breeding or wintering populations. These demographic and movement patterns have important ecological and management implications for understanding goose population structure, harvest of admixed populations, and gene flow among populations with separate breeding or wintering areas. From 1993 to 1996, we neckbanded molting birds at their breeding colonies and resighted birds on the wintering grounds. We used multistate mark-recapture models to evaluate apparent survival rates, resighting rates, winter fidelity, and potential exchange among these populations. We also compared the utility of face stain in Wrangel Island breeding geese as a predictor of their wintering area. Our results showed similar apparent survival rates between subpopulations of Wrangel Island snow geese and lower apparent survival, but higher emigration, for the Banks Island birds. Males had lower apparent survival than females, most likely due to differences in neckband loss. Transition between wintering areas was low (exchange between the Banks and northern Wrangel Island populations. Face staining was an unreliable indicator of wintering area. Our findings suggest that northern and southern

Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography

International Nuclear Information System (INIS)

Hirsch, J.E.

2013-01-01

We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. - Highlights: • A new property of superconducting particles is predicted. • Electron holography will show an apparent increase in thickness at low temperatures. • This will result from a predicted increase in the mean inner potential. • This will originate in expulsion of electrons from the interior to the surface. • This is not predicted by the conventional BCS theory of superconductivity

Diffusion weighted imaging and estimation of prognosis using apparent diffusion coefficient measurements in ischemic stroke

Energy Technology Data Exchange (ETDEWEB)

Gonen, Korcan Aysun, E-mail: aysunbalc@yahoo.com [Department of Radiology, State Hospital, Eski Cami district, Hastane street, N:1, 59300, Tekirdag (Turkey); Simsek, Mehmet Masum, E-mail: radyoloji@haydapasanumune.gov.tr [Department of Radiology, Haydarpasa Numune Training and Research Hospital, Tibbiye street, Uskudar 34200, Istanbul (Turkey)

2010-11-15

Objective: Estimation of the prognosis of infarction by using diffusion weighted imaging (DWI) and quantitative apparent diffusion coefficient (ADC) measurements. Methods: 23 patients having acute stroke symptoms with verified infarction in magnetic resonance imaging (MRI) were included in this study. Their MRI studies were performed between 6 and 12 h after the onset of their symptoms and were repeated on the fifth day. The infarction volumes were calculated by using DWI and the patients were divided into two groups as the ones having an expansion in the infarction area (group 1, n = 16) and the others having no expansion in the infarction area (group 2, n = 7). Quantitative ADC values were estimated. The groups were compared in terms of the ADC values on ADC maps obtained from DWI, performed during the between 6 and 12 h from the onset of the symptoms, referring to the core of the infarction (ADC{sub IC}), ischemic penumbra (ADC{sub P}) and the nonischemic parenchymal tissue (ADC{sub N}). P values < 0.05 were accepted to be statistically significant. Results: During the between 6 and 12 h mean infarction volume calculated by DWI was 23.3 cm{sup 3} for group 1 patients (ranging from 1.1 to 68.6) and this was found to be 40.3 cm{sup 3} (ranging from 1.8 to 91.5) on the fifth day. For the group 2 patients these values were found to be 42.1 cm{sup 3} (ranging from 1 to 94.7) and 41.9 (ranging from 1 to 94.7) for the same intervals respectively. A significant statistical result was failed to be demonstrated between the mean ADC{sub IC} and ADC{sub N} values (p = 0.350 and p = 0.229 respectively). However the comparison of the ADC{sub P} values between the groups was found to be highly significant (p < 0.001). When the differences between the ADC{sub P} and ADC{sub IC} and ADC{sub N} and ADC{sub P} were compared the results proved to be statistically significant (p = 0.038 and p < 0.001 respectively). Conclusions: We believe that ADC results that would be obtained from

Age-related cancer mutations associated with clonal hematopoietic expansion

Science.gov (United States)

Xie, Mingchao; Lu, Charles; Wang, Jiayin; McLellan, Michael D.; Johnson, Kimberly J.; Wendl, Michael C.; McMichael, Joshua F.; Schmidt, Heather K.; Yellapantula, Venkata; Miller, Christopher A.; Ozenberger, Bradley A.; Welch, John S.; Link, Daniel C.; Walter, Matthew J.; Mardis, Elaine R.; Dipersio, John F.; Chen, Feng; Wilson, Richard K.; Ley, Timothy J.; Ding, Li

2015-01-01

Several genetic alterations characteristic of leukemia and lymphoma have been detected in the blood of individuals without apparent hematological malignancies. We analyzed blood-derived sequence data from 2,728 individuals within The Cancer Genome Atlas, and discovered 77 blood-specific mutations in cancer-associated genes, the majority being associated with advanced age. Remarkably, 83% of these mutations were from 19 leukemia/lymphoma-associated genes, and nine were recurrently mutated (DNMT3A, TET2, JAK2, ASXL1, TP53, GNAS, PPM1D, BCORL1 and SF3B1). We identified 14 additional mutations in a very small fraction of blood cells, possibly representing the earliest stages of clonal expansion in hematopoietic stem cells. Comparison of these findings to mutations in hematological malignancies identified several recurrently mutated genes that may be disease initiators. Our analyses show that the blood cells of more than 2% of individuals (5–6% of people older than 70 years) contain mutations that may represent premalignant, initiating events that cause clonal hematopoietic expansion. PMID:25326804

Apparent molar volumes, isobaric expansion coefficients, and isentropic compressibilities, and their H/D isotope effects for some aqueous carbohydrate solutions

International Nuclear Information System (INIS)

Bernal, P.J.; Van Hook, W.A.

1986-01-01

The molar volumes, isobaric expansion coefficients, and isentropic compressibilities of solutions of a number of carbohydrates and their deuterated isomers were determined in H 2 O and D 2 O between 288.15 and 328.15 K and over a wide range of solute-to-solvent mole ratios. The results are discussed in terms of the specific hydration model. (author)

Long-term agricultural land-cover change and potential for cropland expansion in the former Virgin Lands area of Kazakhstan

DEFF Research Database (Denmark)

Kraemer, Roland; Prishchepov, Alexander; Müller, Daniel

2015-01-01

of Northern Kazakhstan. Further, we assessed the potential of currently idle cropland for re-cultivation. We reconstructed the cropland extent before and after the Virgin Lands Campaign using archival maps, and we mapped the agricultural land cover in the late Soviet and post-Soviet period using multi...... until 1990, as well as cropland contraction after 1990, occurred mainly in areas that were less favorable for agriculture. Cropland re-cultivation after 2000 was occurring on lands with relatively favorable agro-environmental conditions in comparison to remaining idle croplands, albeit with much lower...... agro-environmental endowment compared to stable croplands from 1990 to 2010. In sum, we found that cropland production potentials of the currently uncultivated areas are much lower than commonly believed, and further cropland expansion is only possible at the expense of marginal lands. Our results...

Indo-Pacific Warm Pool Area Expansion, Modoki Activity, and Tropical Cold-Point Tropopause Temperature Variations

Science.gov (United States)

Xie, Fei; Li, Jianping; Tian, Wenshou; Li, Yanjie; Feng, Juan

2014-01-01

The tropical cold-point tropopause temperature (CPTT), a potentially important indicator of global climate change, is of particular importance for understanding changes in stratospheric water vapor levels. Since the 1980s, the tropical CPTT has shown not only interannual variations, but also a decreasing trend. However, the factors controlling the variations in the tropical CPTT since the 1980s remain elusive. The present study reveals that the continuous expansion of the area of the Indo-Pacific warm pool (IPWP) since the 1980s represents an increase in the total heat energy of the IPWP available to heat the tropospheric air, which is likely to expand as a result. This process lifts the tropical cold-point tropopause height (CPTH) and leads to the observed long-term cooling trend of the tropical CPTT. In addition, our analysis shows that Modoki activity is an important factor in modulating the interannual variations of the tropical CPTT through significant effects on overshooting convection. PMID:24686481

Adsorption of ionic surfactants at microscopic air-water interfaces using the micropipette interfacial area-expansion method

DEFF Research Database (Denmark)

Kinoshita, Koji; Parra, Elisa; Needham, David

2017-01-01

The dynamic adsorption of ionic surfactants at air-water interfaces have been less-well studied than that of the simpler non-ionics since experimental limitations on dynamic surface tension (DST) measurements create inconsistencies in their kinetic analysis. Using our newly designed "Micropipette...... interfacial area-expansion method", we have measured and evaluated both equilibrium and dynamic adsorption of a well-known anionic surfactant, sodium dodecyl sulphate (SDS), in the absence or presence of 100mM NaCl. Our focus was to determine if and to what extent the inclusion of a new correction parameter...... for the "ideal ionic activity", A±i, can renormalize both equilibrium and dynamic surface tension measurements and provide better estimates of the diffusion coefficient of ionic surfactants in aqueous media obtained from electroneutral models, namely extended Frumkin isotherm and Ward-Tordai adsorption models...

[Multi-scenario simulation and prediction of ecosystem services as affected by urban expansion: A case study in coastal area of Tianjin, North China].

Science.gov (United States)

Huang, Huan-Chun; Yun, Ying-Xia; Miao, Zhan-Tang; Hao, Cui; Li, Hong-yuan

2013-03-01

Based on the modified Logistic-CA model, and taking the coastal area of Tianjin as a case, this paper simulated the spatial evolution patterns of ecosystem services as affected by the urban expansion in 2011-2020 under the scenarios of historical extrapolation, endogenous development, and exogenous development. Overall, the total ecosystem services of the study area under the three scenarios were generally the same, and the functional region with the lowest level ecosystem services had the identical spatial pattern. However, the spatial evolution patterns of the ecosystem services of the study area under the three scenarios had a great difference. The functional regions with lower-level ecosystem services grew in a cross-shaped pattern, with the Tanggu downtown as a center, and finally formed a full connectivity area along the Haihe River and coastal zone.

Expansion of passive safety function

International Nuclear Information System (INIS)

Inai, Nobuhiko; Nei, Hiromichi; Kumada, Toshiaki.

1995-01-01

Expansion of the use of passive safety functions is proposed. Two notions are presented. One is that, in the design of passive safety nuclear reactors where aversion of active components is stressed, some active components are purposely introduced, by which a system is built in such a way that it behaves in an apparently passive manner. The second notion is that, instead of using a passive safety function alone, a passive safety function is combined with some active components, relating the passivity in the safety function with enhanced controllability in normal operation. The nondormant system which the authors propose is one example of the first notion. This is a system in which a standby safety system is a portion of the normal operation system. An interpretation of the nondormant system via synergetics is made. As an example of the second notion, a PIUS density lock aided with active components is proposed and is discussed

Isentropic expansion and related thermodynamic properties of non-ionic amphiphile-water mixtures.

Science.gov (United States)

Reis, João Carlos R; Douhéret, Gérard; Davis, Michael I; Fjellanger, Inger Johanne; Høiland, Harald

2008-01-28

A concise thermodynamic formalism is developed for the molar isentropic thermal expansion, ES,m = ( partial differential Vm/ partial differential T)(Sm,x), and the ideal and excess quantities for the molar, apparent molar and partial molar isentropic expansions of binary liquid mixtures. Ultrasound speeds were determined by means of the pulse-echo-overlap method in aqueous mixtures of 2-methylpropan-2-ol at 298.15 K over the entire composition range. These data complement selected extensive literature data on density, isobaric heat capacity and ultrasound speed for 9 amphiphile (methanol, ethanol, propan-1-ol, propan-2-ol, 2-methylpropan-2-ol, ethane-1,2-diol, 2-methoxyethanol, 2-ethoxyethanol or 2-butoxyethanol)-water binary systems, which form the basis of tables listing molar and excess molar isobaric expansions and heat capacities, and molar and excess molar isentropic compressions and expansions at 298.15 K and at 65 fixed mole fractions spanning the entire composition range and fine-grained in the water-rich region. The dependence on composition of these 9 systems is graphically depicted for the excess molar isobaric and isentropic expansions and for the excess partial molar isobaric and isentropic expansions of the amphiphile. The analysis shows that isentropic thermal expansion properties give a much stronger response to amphiphile-water molecular interactions than do their isobaric counterparts. Depending on the pair property-system, the maximum excess molar isentropic value is generally twenty- to a hundred-fold greater than the corresponding maximum isobaric value, and occurs at a lower mole fraction of the amphiphile. Values at infinite dilution of the 9 amphiphiles in water are given for the excess partial molar isobaric heat capacity, isentropic compression, isobaric expansion and isentropic expansion. These values are interpreted in terms of the changes occurring when amphiphile molecules cluster into an oligomeric form. Present results are discussed

Negative thermal expansion up to 1000 C of ZrTiO4-Al2TiO5 ceramics for high-temperature applications

International Nuclear Information System (INIS)

Kim, I.J.; Kim, H.C.; Han, I.S.; Aneziris, C.G.

2005-01-01

High temperature structural ceramics based on Al 2 TiO 5 -ZrTiO 4 (ZAT) having excellent thermal-shock-resistance were synthesized by a reaction sintering. The ZAT ceramics sintered at 1600 C had a negative thermal expansions up to 1000 C and a much lower thermal expansion coefficient (0.3 ∝ 1.3 x 10 -6 /K) than that of polycrystalline Al 2 TiO 5 (1.5 x 10 -6 /K). These low thermal expansion are apparently due to a combination of microcracking caused by the large thermal expansion anisotropy of the crystal axes of the Al 2 TiO 5 phase. The microstructural degradation of the composites after various thermal treatment for high temperature applications were analyzed by scanning electron microscopy, X-ray diffraction, ultrasonic and dilatometer. (orig.)

Assessment on the Expansion of Basic Sanitation Infrastructure. In the Metropolitan Area of Belo Horizonte - 2000/2010

Directory of Open Access Journals (Sweden)

Grazielle Anjos Carvalho

2014-05-01

Full Text Available The Metropolitan Area of Belo Horizonte is consisted of 34 municipalities, however approximately 79,68% of its population is concentrated at the conurbation zone with 19 municipalities. This zone presented different expansion axis (North, South, West throughout the time. This article intends to assess the investments made in basic sanitation infrastructure (access to water supply, sewage collection network and garbage collection service within the period from the years 2000 to 2010. For this purpose, land cover maps for these years were created to identify the new urban expansion axis. Maps of the census sectors of both years were also made with the percentage of households attended by the basic sanitation services infrastructure, as well as the population density and average income of the householder. Considering the results, we have observed that the investments in basic sanitation infrastructure in the last ten years were not sufficient, given the fact that the region with the largest population of Minas Gerais still has precarious conditions regarding the access to water supply and sewage networks. The least of the problems, but still a problem, is the garbage collection services, given the fact that to collect, the investment is low but it is important to highlight that the data do not bring information about the treatment and disposal of the garbage or sewage, they only inform us were those types of residue are collected.

A meta-analysis of global urban land expansion.

Science.gov (United States)

Seto, Karen C; Fragkias, Michail; Güneralp, Burak; Reilly, Michael K

2011-01-01

The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km(2) from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km(2) and 12,568,000 km(2), with an estimate of 1,527,000 km(2) more likely.

Cathode plasma expansion in diode with explosive emission

International Nuclear Information System (INIS)

Zuo Yinghong; Fan Ruyu; Wang Jianguo; Zhu Jinhui

2012-01-01

The evolution characteristics of the cathode plasma in a planar diode with explosive emission were analyzed. Be- sides the axial expansion which can reduce the effective anode-cathode gap, the radial expansion of the cathode plasma which can affect the effective emitting area was also taken into account. According to the Child-Langmuir law and the experimental data of current and voltage with a electron vacuum diode under four-pulse mode, the dynamics of the cathode plasma was investigated, on the assumption that the radial speeds of the cathode plasma was approximately equal to the axial speed. The results show that the radial and axial expansion speeds of the cathode plasma are 0.9-2.8 cm/μs. (authors)

Modeling a space-variant cortical representation for apparent motion.

Science.gov (United States)

Wurbs, Jeremy; Mingolla, Ennio; Yazdanbakhsh, Arash

2013-08-06

Receptive field sizes of neurons in early primate visual areas increase with eccentricity, as does temporal processing speed. The fovea is evidently specialized for slow, fine movements while the periphery is suited for fast, coarse movements. In either the fovea or periphery discrete flashes can produce motion percepts. Grossberg and Rudd (1989) used traveling Gaussian activity profiles to model long-range apparent motion percepts. We propose a neural model constrained by physiological data to explain how signals from retinal ganglion cells to V1 affect the perception of motion as a function of eccentricity. Our model incorporates cortical magnification, receptive field overlap and scatter, and spatial and temporal response characteristics of retinal ganglion cells for cortical processing of motion. Consistent with the finding of Baker and Braddick (1985), in our model the maximum flash distance that is perceived as an apparent motion (Dmax) increases linearly as a function of eccentricity. Baker and Braddick (1985) made qualitative predictions about the functional significance of both stimulus and visual system parameters that constrain motion perception, such as an increase in the range of detectable motions as a function of eccentricity and the likely role of higher visual processes in determining Dmax. We generate corresponding quantitative predictions for those functional dependencies for individual aspects of motion processing. Simulation results indicate that the early visual pathway can explain the qualitative linear increase of Dmax data without reliance on extrastriate areas, but that those higher visual areas may serve as a modulatory influence on the exact Dmax increase.

The future of Arctic benthos: Expansion, invasion, and biodiversity

Science.gov (United States)

Renaud, Paul E.; Sejr, Mikael K.; Bluhm, Bodil A.; Sirenko, Boris; Ellingsen, Ingrid H.

2015-12-01

One of the logical predictions for a future Arctic characterized by warmer waters and reduced sea-ice is that new taxa will expand or invade Arctic seafloor habitats. Specific predictions regarding where this will occur and which taxa are most likely to become established or excluded are lacking, however. We synthesize recent studies and conduct new analyses in the context of climate forecasts and a paleontological perspective to make concrete predictions as to relevant mechanisms, regions, and functional traits contributing to future biodiversity changes. Historically, a warmer Arctic is more readily invaded or transited by boreal taxa than it is during cold periods. Oceanography of an ice-free Arctic Ocean, combined with life-history traits of invading taxa and availability of suitable habitat, determine expansion success. It is difficult to generalize as to which taxonomic groups or locations are likely to experience expansion, however, since species-specific, and perhaps population-specific autecologies, will determine success or failure. Several examples of expansion into the Arctic have been noted, and along with the results from the relatively few Arctic biological time-series suggest inflow shelves (Barents and Chukchi Seas), as well as West Greenland and the western Kara Sea, are most likely locations for expansion. Apparent temperature thresholds were identified for characteristic Arctic and boreal benthic fauna suggesting strong potential for range constrictions of Arctic, and expansions of boreal, fauna in the near future. Increasing human activities in the region could speed introductions of boreal fauna and reduce the value of a planktonic dispersal stage. Finally, shelf regions are likely to experience a greater impact, and also one with greater potential consequences, than the deep Arctic basin. Future research strategies should focus on monitoring as well as compiling basic physiological and life-history information of Arctic and boreal taxa, and

The volume of fluid injected into the tissue expander and the tissue expansion

Directory of Open Access Journals (Sweden)

Mahmood Omranifard

2014-01-01

Full Text Available Background: Replacement of the lost tissue is the major concerns of the plastic surgeons. Expanded area should be coherent with the surrounding tissue. Tissue expansion technique is the reforming methods the skin tissue scarcities. Several methods for tissue expansion are available; including usage of silicon balloon and injecting fluid into the tissue expander. Materials and Methods: In a clinical trial study, 35 patients, with burn scars, in the face, skull and neck area were studied. We provided a tissue expander device with capacities of 125, 250 and 350cc. Fluid was injected inside the device, 3 consecutive weeks with 1-week interval. After 3 months the device was set out and the tissue expansion was measured using a transparent board and the results were analyzed. Multiple regression was done by SPSS 20 to analyze the data. Results: Regression model showed Skin expansion was positively correlated with the volume of the injected fluid. For each centimeter square of skin expansion, about 6-8 ml of fluid must be injected. Conclusion: Correction of skin defects resulting from burning scar is possible using tissue expanders. The tissue expansion is correlated with the amount of the injected fluid.

Seasonal hydroclimatic impacts of Sun Corridor expansion

International Nuclear Information System (INIS)

Georgescu, M; Mahalov, A; Moustaoui, M

2012-01-01

Conversion of natural to urban land forms imparts influence on local and regional hydroclimate via modification of the surface energy and water balance, and consideration of such effects due to rapidly expanding megapolitan areas is necessary in light of the growing global share of urban inhabitants. Based on a suite of ensemble-based, multi-year simulations using the Weather Research and Forecasting (WRF) model, we quantify seasonally varying hydroclimatic impacts of the most rapidly expanding megapolitan area in the US: Arizona’s Sun Corridor, centered upon the Greater Phoenix metropolitan area. Using a scenario-based urban expansion approach that accounts for the full range of Sun Corridor growth uncertainty through 2050, we show that built environment induced warming for the maximum development scenario is greatest during the summer season (regionally averaged warming over AZ exceeds 1 °C). Warming remains significant during the spring and fall seasons (regionally averaged warming over AZ approaches 0.9 °C during both seasons), and is least during the winter season (regionally averaged warming over AZ of 0.5 °C). Impacts from a minimum expansion scenario are reduced, with regionally averaged warming ranging between 0.1 and 0.3 °C for all seasons except winter, when no warming impacts are diagnosed. Integration of highly reflective cool roofs within the built environment, increasingly recognized as a cost-effective option intended to offset the warming influence of urban complexes, reduces urban-induced warming considerably. However, impacts on the hydrologic cycle are aggravated via enhanced evapotranspiration reduction, leading to a 4% total accumulated precipitation decrease relative to the non-adaptive maximum expansion scenario. Our results highlight potentially unintended consequences of this adaptation approach within rapidly expanding megapolitan areas, and emphasize the need for undeniably sustainable development paths that account for

Measurement of thermal expansion for a Li2TiO3 pebble bed

International Nuclear Information System (INIS)

Hisashi Tanigawa; Mikio Enoeda; Masato Akiba

2006-01-01

were loaded before the measurements, expansion coefficients were the largest in the first heating process. When the pre-loaded beds were heated, deformation caused by the pre-loading was relaxed. Hence, apparent expansion coefficient increased. The result suggests that residual stress in the bed cased by a compressive load can be annealed when the bed is heated without load. Based on the observed expansion behaviour, preferable initial packing state and its variation during the operation were discussed. (author)

On the Convergence of the Virial Expansion

NARCIS (Netherlands)

Ramawadh, S.D.

2015-01-01

The virial expansion appears in statistical mechanics, an area where physics and mathematics intersect. Throughout this thesis we will mostly ignore the physics and mainly focus on the mathematical aspects. This is a deliberate choice, made for two reasons. Firstly, there are several books that

Quantitative analysis of urban sprawl in Tripoli using Pearson's Chi-Square statistics and urban expansion intensity index

International Nuclear Information System (INIS)

Al-sharif, Abubakr A A; Pradhan, Biswajeet; Shafri, Helmi Zulhaidi Mohd; Mansor, Shattri

2014-01-01

Urban expansion is a spatial phenomenon that reflects the increased level of importance of metropolises. The remotely sensed data and GIS have been widely used to study and analyze the process of urban expansions and their patterns. The capital of Libya (Tripoli) was selected to perform this study and to examine its urban growth patterns. Four satellite imageries of the study area in different dates (1984, 1996, 2002 and 2010) were used to conduct this research. The main goal of this work is identification and analyzes the urban sprawl of Tripoli metropolitan area. Urban expansion intensity index (UEII) and degree of freedom test were used to analyze and assess urban expansions in the area of study. The results show that Tripoli has sprawled urban expansion patterns; high urban expansion intensity index; and its urban development had high degree of freedom according to its urban expansion history during the time period (1984-2010). However, the novel proposed hypothesis used for zones division resulted in very good insight understanding of urban expansion direction and the effect of the distance from central business of district (CBD)

Thermal expansion

International Nuclear Information System (INIS)

Yun, Y.

2015-01-01

Thermal expansion of fuel pellet is an important property which limits the lifetime of the fuels in reactors, because it affects both the pellet and cladding mechanical interaction and the gap conductivity. By fitting a number of available measured data, recommended equations have been presented and successfully used to estimate thermal expansion coefficient of the nuclear fuel pellet. However, due to large scatter of the measured data, non-consensus data have been omitted in formulating the equations. Also, the equation is strongly governed by the lack of appropriate experimental data. For those reasons, it is important to develop theoretical methodologies to better describe thermal expansion behaviour of nuclear fuel. In particular, first-principles and molecular dynamics simulations have been certainly contributed to predict reliable thermal expansion without fitting the measured data. Furthermore, the two theoretical techniques have improved on understanding the change of fuel dimension by describing the atomic-scale processes associated with lattice expansion in the fuels. (author)

Low-temperature thermal expansion

International Nuclear Information System (INIS)

Collings, E.W.

1986-01-01

This chapter discusses the thermal expansion of insulators and metals. Harmonicity and anharmonicity in thermal expansion are examined. The electronic, magnetic, an other contributions to low temperature thermal expansion are analyzed. The thermodynamics of the Debye isotropic continuum, the lattice-dynamical approach, and the thermal expansion of metals are discussed. Relative linear expansion at low temperatures is reviewed and further calculations of the electronic thermal expansion coefficient are given. Thermal expansions are given for Cu, Al and Ti. Phenomenologic thermodynamic relationships are also discussed

Spatio-temporal evolution of apparent resistivity during coal-seam hydraulic flushing

Science.gov (United States)

Li, Dexing; Wang, Enyuan; Song, Dazhao; Qiu, Liming; Kong, Xiangguo

2018-06-01

Hydraulic flushing in gas predrainage is widely used, but the hydraulic-flushing effect is evaluated in a traditional way, by determining the desorption volume, moisture content, gas drainage rate and other conventional indices. To verify the rationality and feasibility of the multielectrode resistivity method in the evaluation of coal-seam hydraulic flushing and to research the spatio-temporal evolution of apparent resistivity during hydraulic flushing, a field test was conducted in 17# coal seam at Nuodong Mine, Guizhou. During hydraulic flushing, four stages were defined according to the variation in coal rock resistivity with time, namely, the preparation stage, the sharply decreasing stage, the rapidly increasing stage and the steady stage. The apparent resistivity of the coal rock mass is affected mainly by its own degree of fragmentation and flushing volume. A more serious rupture and a greater flushing volume yield a smaller apparent resistivity during the sharply decreasing stage and a higher resistivity during the stable stage. After three months of gas predrainage, the residual gas content and the gas pressure at different points in the expected affected area decrease below the critical value. Changes in the residual gas content and gas pressure at these points are consistent with the apparent resistivity, which validates the rationality and feasibility of the multielectrode resistivity method in evaluating coal-seam hydraulic flushing.

Theoretical and experimental studies of the orbit expansion effect

International Nuclear Information System (INIS)

Glazov, A.A.; Denisov, Yu.N.; Dmitrievskij, V.P.

1985-01-01

Calculation and experiment results of investigations on the orbit expansion effect in the periodic magnetic structures are considered. Experiments, conducted with the use of ring cyclotron electron model, have shown, that the orbit expansion effect leads to the beam cross section radial size increase. This phenomenon was eliminated through the introduction of correction coils, which provide for the required low harmonic phase and value change in the whole acceleration area. Energy spread leads to the spreading of beam in the expansion area. Numeric calculations show, that for the electron model used the relative energy spread must be less than 10 -3 . The conclusion is drawn, that the only real possibility to obtain an accelerated beam with such an energy spread is to perform the ''flat-top'' regime. Equipment for cyclotron electron model RF supply is developed and produced to realise this regime. Particle dinamics calculation in the ''flat-top'' regime and the first experiments have shown, that acceleration asymmetry leads to the rapid coherent oscillation swing in the centre up to the amplitude of 6-7 sm

Urban Land Expansion and Spatial Dynamics in Globalizing Shanghai

Directory of Open Access Journals (Sweden)

Han Li

2014-12-01

Full Text Available Urban land expansion in China has attracted considerable scholarly attention. However, more work is needed to apply spatial modeling to understanding the mechanisms of urban growth from both institutional and physical perspectives. This paper analyzes urban expansion in Shanghai and its development zones (DZs. We find that, as nodes of global-local interface, the DZs are the most significant components of urban growth in Shanghai, and major spatial patterns of urban expansion in Shanghai are infilling and edge expansion. We apply logistic regression, geographically weighted logistic regression (GWLR and spatial regime regression to investigate the determinants of urban land expansion including physical conditions, state policy and land development. Regressions reveal that, though the market has been an important driving force in urban growth, the state has played a predominant role through the implementation of urban planning and the establishment of DZs to fully capitalize on globalization. We also find that differences in urban growth dynamics exist between the areas inside and outside of the DZs. Finally, this paper discusses policies to promote sustainable development in Shanghai.

Relict or colonizer? Extinction and range expansion of penguins in southern New Zealand

Science.gov (United States)

Boessenkool, Sanne; Austin, Jeremy J.; Worthy, Trevor H.; Scofield, Paul; Cooper, Alan; Seddon, Philip J.; Waters, Jonathan M.

2008-01-01

Recent human expansion into the Pacific initiated a dramatic avian extinction crisis, and surviving taxa are typically interpreted as declining remnants of previously abundant populations. As a case in point, New Zealand's endangered yellow-eyed penguin (Megadyptes antipodes) is widely considered to have been more abundant and widespread in the past. By contrast, our genetic and morphological analyses of prehistoric, historic and modern penguin samples reveal that this species expanded its range to the New Zealand mainland only in the last few hundred years. This range expansion was apparently facilitated by the extinction of M. antipodes' previously unrecognized sister species following Polynesian settlement in New Zealand. Based on combined genetic and morphological data, we describe this new penguin species, the first known to have suffered human-mediated extinction. The range expansion of M. antipodes so soon after the extinction of its sister species supports a historic paradigmatic shift in New Zealand Polynesian culture. Additionally, such a dynamic biological response to human predation reveals a surprising and less recognized potential for species to have benefited from the extinction of their ecologically similar sister taxa and highlights the complexity of large-scale extinction events. PMID:19019791

Shrub expansion in SW Greenland

DEFF Research Database (Denmark)

Jørgensen, Rasmus Halfdan

Arctic regions have experienced higher temperatures in recent decades, and the warming trend is projected to continue in the coming years. Arctic ecosystems are considered to be particularly vulnerable to climate change. Expansion of shrubs has been observed widely in tundra areas across the Arctic......, and has a range of ecosystem effects where it occurs. Shrub expansion has to a large extend been attributed to increasing temperatures over the past century, while grazing and human disturbance have received less attention. Alnus viridis ssp. crispa is a common arctic species that contributes...... to increasing shrub cover. Despite this, there is only limited experimental evidence that growth of the species responds to warming. Plant populations in fragmented and isolated locations could face problems adapting to a warming climate due to limited genetic variation and restricted migration from southern...

Spatial patterns of agricultural expansion determine impacts on biodiversity and carbon storage.

Science.gov (United States)

Chaplin-Kramer, Rebecca; Sharp, Richard P; Mandle, Lisa; Sim, Sarah; Johnson, Justin; Butnar, Isabela; Milà I Canals, Llorenç; Eichelberger, Bradley A; Ramler, Ivan; Mueller, Carina; McLachlan, Nikolaus; Yousefi, Anahita; King, Henry; Kareiva, Peter M

2015-06-16

The agricultural expansion and intensification required to meet growing food and agri-based product demand present important challenges to future levels and management of biodiversity and ecosystem services. Influential actors such as corporations, governments, and multilateral organizations have made commitments to meeting future agricultural demand sustainably and preserving critical ecosystems. Current approaches to predicting the impacts of agricultural expansion involve calculation of total land conversion and assessment of the impacts on biodiversity or ecosystem services on a per-area basis, generally assuming a linear relationship between impact and land area. However, the impacts of continuing land development are often not linear and can vary considerably with spatial configuration. We demonstrate what could be gained by spatially explicit analysis of agricultural expansion at a large scale compared with the simple measure of total area converted, with a focus on the impacts on biodiversity and carbon storage. Using simple modeling approaches for two regions of Brazil, we find that for the same amount of land conversion, the declines in biodiversity and carbon storage can vary two- to fourfold depending on the spatial pattern of conversion. Impacts increase most rapidly in the earliest stages of agricultural expansion and are more pronounced in scenarios where conversion occurs in forest interiors compared with expansion into forests from their edges. This study reveals the importance of spatially explicit information in the assessment of land-use change impacts and for future land management and conservation.

Evaluating population expansion of black bears using spatial capture-recapture

Science.gov (United States)

Sun, Catherine C.; Fuller, Angela K.; Hare, Matthew P.; Hurst, Jeremy E.

2017-01-01

The population of American black bears (Ursus americanus) in southern New York, USA has been growing and expanding in range since the 1990s. This has motivated a need to anticipate future patterns of range expansion. We conducted a non-invasive, genetic, spatial capture-recapture (SCR) study to estimate black bear density and identify spatial patterns of population density that are potentially associated with range expansion. We collected hair samples in a 2,519-km2 study area in southern New York with barbed-wire hair snares and identified individuals and measured genetic diversity using 7 microsatellite loci and 1 sex-linked marker. We estimated a mean density of black bears in the region of 13.7 bears/100 km2, and detected a slight latitudinal gradient in density consistent with the documented range expansion. However, elevation and the amounts of forest, crop, and developed landcover types did not influence density, suggesting that bears are using a diversity of resources in this heterogeneous landscape outside their previously described distribution. These results provide the first robust baseline estimates for population density and distribution associated with different landcover types in the expanded bear range. Further, genetic diversity was comparable to that of non-expanding black bear populations in the eastern United States, and in combination with the latitudinal density gradient, suggest that the study area is not at the colonizing front of the range expansion. In addition, the diversity of landcover types used by bears in the study area implies a possible lack of constraints for further northern expansion of the black bear range. Our non-invasive, genetic, spatial capture-recapture approach has utility for studying populations of other species that may be expanding in range because SCR allows for the testing of explicit, spatial ecological hypotheses. 

Reduction Expansion Synthesis as Strategy to Control Nitrogen Doping Level and Surface Area in Graphene

Directory of Open Access Journals (Sweden)

Russell Canty

2015-10-01

Full Text Available Graphene sheets doped with nitrogen were produced by the reduction-expansion (RES method utilizing graphite oxide (GO and urea as precursor materials. The simultaneous graphene generation and nitrogen insertion reactions are based on the fact that urea decomposes upon heating to release reducing gases. The volatile byproducts perform two primary functions: (i promoting the reduction of the GO and (ii providing the nitrogen to be inserted in situ as the graphene structure is created. Samples with diverse urea/GO mass ratios were treated at 800 °C in inert atmosphere to generate graphene with diverse microstructural characteristics and levels of nitrogen doping. Scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to study the microstructural features of the products. The effects of doping on the samples structure and surface area were studied by X-ray diffraction (XRD, Raman Spectroscopy, and Brunauer Emmet Teller (BET. The GO and urea decomposition-reduction process as well as nitrogen-doped graphene stability were studied by thermogravimetric analysis (TGA coupled with mass spectroscopy (MS analysis of the evolved gases. Results show that the proposed method offers a high level of control over the amount of nitrogen inserted in the graphene and may be used alternatively to control its surface area. To demonstrate the practical relevance of these findings, as-produced samples were used as electrodes in supercapacitor and battery devices and compared with conventional, thermally exfoliated graphene.

Remembering apparent behavior

DEFF Research Database (Denmark)

Wagoner, Brady

2011-01-01

The present experiment systematically investigates the role of narrative templates (Wertsch, 2002) in remembering. To stimulate the construction of a diversity of narratives I used Heider and Simmel’s (1944) celebrated “apparent behavior” film, in which geometric shapes moving around a screen...

Functional differential equation approach to the large N expansion and mean field perturbation theory

International Nuclear Information System (INIS)

Bender, C.M.; Cooper, F.

1985-01-01

An apparent difference between formulating mean field perturbation theory for lambdaphi 4 field theory via path integrals or via functional differential equations when there are external sources present is shown not to exist when mean field theory is considered as the N = 1 limit of the 0(N)lambdaphi 4 field theory. A simply method is given for determining the 1/N expansion for the Green's functions in the presence of external sources by directly solving the functional differential equations order by order in 1/N. The 1/N expansion for the effective action GAMMA(phi,chi) is obtained by directly integrating the functional differential equations for the fields phi and chi (equivalent1/2lambda/Nphi/sub α/phi/sup α/-μ 2 ) in the presence of two external sources j = -deltaGAMMA/deltaphi, S = -deltaGAMMA/deltachi

Apparent target strength in long-rod penetration

Energy Technology Data Exchange (ETDEWEB)

Godwin, R.P.; Chapyak, E.J. [Los Alamos National Lab., NM (United States). Applied Theoretical and Computational Physics Div.

1996-03-01

The authors investigate the apparent enhancement of target strength in the steady-state Tate model of long-rod penetration. They show that computing the effective area over which the target behaves as a fluid provides an explanation of the effective 1-D target strength measured empirically. Expressing the effective target strength as R{sub t} = a {times} Y{sub t}, they postulate that a = A{sub e}/A{sub p}, where Y{sub t} is the nominal strength; A{sub e} is the effective target fluid cross-sectional area and A{sub p} the projectile cross-sectional area. For the case of a rod and projectile of the same material, they use the Tate model together with the jet model of Birkhoff et al. to show a {approx} 4 is likely. Simultaneously satisfying Newton`s Second Law and the Tate model yields a very general derivation of a = 4. By explicitly including strength terms in both the Tate equation and Newton`s Second Law, an even more general a = f(v,{rho}{sub p},{rho}{sub t},Y{sub p},Y{sub t}) can be derived.

Cryo-electron microscopy and single molecule fluorescent microscopy detect CD4 receptor induced HIV size expansion prior to cell entry

International Nuclear Information System (INIS)

Pham, Son; Tabarin, Thibault; Garvey, Megan; Pade, Corinna; Rossy, Jérémie; Monaghan, Paul; Hyatt, Alex; Böcking, Till; Leis, Andrew; Gaus, Katharina; Mak, Johnson

2015-01-01

Viruses are often thought to have static structure, and they only remodel after the viruses have entered target cells. Here, we detected a size expansion of virus particles prior to viral entry using cryo-electron microscopy (cryo-EM) and single molecule fluorescence imaging. HIV expanded both under cell-free conditions with soluble receptor CD4 (sCD4) targeting the CD4 binding site on the HIV-1 envelope protein (Env) and when HIV binds to receptor on cellular membrane. We have shown that the HIV Env is needed to facilitate receptor induced virus size expansions, showing that the ‘lynchpin’ for size expansion is highly specific. We demonstrate that the size expansion required maturation of HIV and an internal capsid core with wild type stability, suggesting that different HIV compartments are linked and are involved in remodelling. Our work reveals a previously unknown event in HIV entry, and we propose that this pre-entry priming process enables HIV particles to facilitate the subsequent steps in infection. - Highlights: • Cell free viruses are able to receive external trigger that leads to apparent size expansion. • Virus envelope and CD4 receptor engagement is the lynchpin of virus size expansion. • Internal capsid organisation can influence receptor mediated virus size expansion. • Pre-existing virus-associated lipid membrane in cell free virus can accommodate the receptor mediated virus size expansion.

Cryo-electron microscopy and single molecule fluorescent microscopy detect CD4 receptor induced HIV size expansion prior to cell entry

Energy Technology Data Exchange (ETDEWEB)

Pham, Son [Deakin University, Victoria 3216 (Australia); CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Tabarin, Thibault [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Garvey, Megan; Pade, Corinna [Deakin University, Victoria 3216 (Australia); CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Rossy, Jérémie [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Monaghan, Paul; Hyatt, Alex [CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Böcking, Till [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Leis, Andrew [CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia); Gaus, Katharina, E-mail: k.gaus@unsw.edu.au [ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, New South Wales 3220 (Australia); Mak, Johnson, E-mail: j.mak@deakin.edu.au [Deakin University, Victoria 3216 (Australia); CSIRO Australian Animal Health Laboratory, Victoria 3220 (Australia)

2015-12-15

Viruses are often thought to have static structure, and they only remodel after the viruses have entered target cells. Here, we detected a size expansion of virus particles prior to viral entry using cryo-electron microscopy (cryo-EM) and single molecule fluorescence imaging. HIV expanded both under cell-free conditions with soluble receptor CD4 (sCD4) targeting the CD4 binding site on the HIV-1 envelope protein (Env) and when HIV binds to receptor on cellular membrane. We have shown that the HIV Env is needed to facilitate receptor induced virus size expansions, showing that the ‘lynchpin’ for size expansion is highly specific. We demonstrate that the size expansion required maturation of HIV and an internal capsid core with wild type stability, suggesting that different HIV compartments are linked and are involved in remodelling. Our work reveals a previously unknown event in HIV entry, and we propose that this pre-entry priming process enables HIV particles to facilitate the subsequent steps in infection. - Highlights: • Cell free viruses are able to receive external trigger that leads to apparent size expansion. • Virus envelope and CD4 receptor engagement is the lynchpin of virus size expansion. • Internal capsid organisation can influence receptor mediated virus size expansion. • Pre-existing virus-associated lipid membrane in cell free virus can accommodate the receptor mediated virus size expansion.

Expansion design for a Laboratory of Radioactive Sources Handling type II, class B

International Nuclear Information System (INIS)

Sanchez S, P. S.

2014-01-01

This work presents the expansion design of the Radioactive Wastes Research Laboratory (RWRL) installation authorized by the Comision Nacional de Seguridad Nuclear y Salvaguardias (Mexico) as type II class C, to manage 40 different radionuclides, approximately. The RWRL has 4 areas at the present time: a laboratory of instrumental analysis, one of radioactive material processes, other of counting and a chemical reagents stock, which is not integrated to the operation license of the RWRL. With the purpose of expanding the operation license of the RWRL to an installation type II class B, to manage until 370 MBq of high radio toxicity radionuclides, is presented in this work an expansion proposal of the RWRL. The expansion proposal is based in: (1) the Mexican Nuclear Standard NOM-027-Nucl-1996 for installations type II class B, (2) the current distribution of water, light, electricity, extraction, gas, air and vacuum services of RWRL, and (3) the available areas inside the building that the RWRL occupies. The proposal contemplates the creation of additional new areas for RWRL: 3 laboratories, 2 dressing rooms, 2 bathrooms and 2 warehouses, one for radioactive materials and another for reagents chemical radiologically inactive. Architectural, electric, hydraulic, extraction and gas planes corresponding to the expansion of RWRL were realized. Inside the proposal the budget required to carry out the mentioned expansion is also presented. (Author)

Landscape structure in the expansion area of deforestation of the Brazilian Cerrado in Minas Gerais

Science.gov (United States)

Brito, A. D.; Streher, A. S.

2013-05-01

The Cerrado is the second largest Brazilian biome and is listed as one of the hotspots for biodiversity conservation priority. The biome provides important ecosystem services such as maintenance of the biodiversity, water cycle and carbon storage, and your preservation is essential to protecting the Amazon Rainforest. Although its importance, it was heavily affected by deforestation, with a loss of about 49% of its original native cover by the year of 2010. In Minas Gerais state, the remaining Cerrado original cover is very expressive, shaped by a mosaic of phytophysionomies, comprising grassland, savanna and forest. The great species diversity and endemism in these landscapes, associated with changes imposed by man over time, caused major environmental damage in this biome. Recently, new deforestation fronts have been identified throughout the Brazilian Cerrado, including Minas Gerais State. This study aimed to analyze the landscape structure in front of expansion in this state, as a subsidy for the establishment of guidelines for future biodiversity conservation and landscape planning. The study site comprised the sub basins of the Paracatú River (SF7) and Middle São Francisco (SF9). The analyses were performed based on land use, mapped through remote sensing techniques, resulting in 18 classes of land use. The most important results of the calculated indices showed that the study area is highly fragmented, with most of the remaining patches small, with large perimeter and strong edge effect, favoring biodiversity loss. Moreover, the biological flow in the study area is hindered by the presence of few fragments into a predetermined radius of 10 km. It has been found that less than 30% of the native vegetation remnant in the area, making all existing fragments relevant to conservation. Finally, the landscape metrics analyzed showed that there is a high level of environmental risk determining low support existing biodiversity in the landscape.

Apparent molar volumes and compressibilities of lanthanum, gadolinium, lutetium and sodium trifluoromethanesulfonates in N,N-dimethylformamide and N,N-dimethylacetamide

International Nuclear Information System (INIS)

Warmińska, Dorota; Fuchs, Anna; Lundberg, Daniel

2013-01-01

Highlights: ► In DMF the sequence values of both volumes and compressibilities of Ln 3+ ions are: La 3+ ≈ Gd 3+ > Lu 3+ . ► In DMA the ionic volumes of lanthanoid(III) metal ions are, within error limits, identical. ► Obtained results are the consequence of an ion–solvent bonding nature. -- Abstract: The concentration and temperature dependencies of density of lanthanum, gadolinium, lutetium and sodium trifluoromethanesulfonates in N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) have been determined. From density data the apparent molar volumes and partial molar volumes of the salts at infinite dilution as well as the expansibilities have been evaluated. The apparent molar isentropic compressibilities of lanthanum, gadolinium, lutetium and sodium trifluoromethanesulfonates in DMF and DMA have been calculated from sound velocity data obtained at 298.15 K. The results have been discussed in terms of ion–solvent interactions

EXPANSION OF HYDROGEN-POOR KNOTS IN THE BORN-AGAIN PLANETARY NEBULAE A30 AND A78

Energy Technology Data Exchange (ETDEWEB)

Fang, X.; Guerrero, M. A.; Marquez-Lugo, R. A.; Toalá, J. A. [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Arthur, S. J. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Campus Morelia, 58090 Morelia (Mexico); Chu, Y.-H.; Gruendl, R. A. [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Blair, W. P. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Hamann, W.-R.; Oskinova, L. M.; Todt, H., E-mail: fangx@iaa.es [Institute for Physics and Astronomy, Universität Potsdam, D-14476 Potsdam (Germany)

2014-12-20

We analyze the expansion of hydrogen-poor knots and filaments in the born-again planetary nebulae A30 and A78 based on Hubble Space Telescope (HST) images obtained almost 20 yr apart. The proper motion of these features generally increases with distance to the central star, but the fractional expansion decreases, i.e., the expansion is not homologous. As a result, there is not a unique expansion age, which is estimated to be 610-950 yr for A30 and 600-1140 yr for A78. The knots and filaments have experienced complex dynamical processes: the current fast stellar wind is mass loaded by the material ablated from the inner knots; the ablated material is then swept up until it shocks the inner edges of the outer, hydrogen-rich nebula. The angular expansion of the outer filaments shows a clear dependence on position angle, indicating that the interaction of the stellar wind with the innermost knots channels the wind along preferred directions. The apparent angular expansion of the innermost knots seems to be dominated by the rocket effect of evaporating gas and by the propagation of the ionization front inside them. Radiation-hydrodynamical simulations show that a single ejection of material followed by a rapid onset of the stellar wind and ionizing flux can reproduce the variety of clumps and filaments at different distances from the central star found in A30 and A78.

Assessing the intersection/remagnetization puzzle with synthetic apparent polar wander paths

Science.gov (United States)

Pivarunas, Anthony F.; Meert, Joseph G.; Miller, Scott R.

2018-05-01

Paleomagnetic data are of variable quality. To assist in a systematic assessment of data, a set of seven quality criteria (VQ1 - VQ7) were introduced by Van der Voo (1990). The last of those criteria `VQ7' concerns the possibility of remagnetization when a particular paleomagnetic pole resembles a younger paleopole from the same stable region. While remagnetizations are often the culprit, the mere resemblance of an older pole to a younger pole does not a priori require that the rocks under investigation are remagnetized. Given that the Earth has a finite surface area; that apparent polar wander paths are represented as wide swathes rather than points, and that continental motion has taken place over several billion years, we ask the question `How likely is it for an apparent polar wander path to loop back on itself?' To answer this question, we constructed synthetic apparent polar wander paths (APWPs) in an effort to evaluate the likelihood of self-intersection. We find that given 500 Myr of apparent polar wander, ˜60 per cent of the synthetic APWPs show self-intersection. Given 1000 Myr of apparent polar wander, ˜95 per cent of the synthetic APWPs show self-intersection. These results show that resemblance to younger paleopoles, over the long term, may be governed by simple probability rather than only remagnetization. We recognize that remagnetization does occur, sometimes pervasively, and must be reckoned with in the assessment of paleomagnetic data. Perhaps VQ7 should be amended to the first sentence in the original discussion (Van der Voo, 1990), and focus on satisfying `No suspicion of remagnetization' via other means rather than solely a resemblance to younger poles.

THE EXPANSION OF THE RITZ-CARLTON® ON FOREIGN MARKETS

OpenAIRE

Mihai-Răzvan DOBAI

2016-01-01

The spreading of globalization drives the companies’ pursuit to expand on foreign markets for various reasons. In this paper it will be analysed the expansion on non-US markets of the Ritz-Carlton®, a hotel company with tradition, being known for its services quality. The analysis takes into consideration the opening year of the hotels in the Latin American, European, Middle Eastern, Central and South Asian and AsiaPacific market, trying to correlate the expansion on certain areas and l...

Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas.

Science.gov (United States)

Tsui, C K; Boedo, J A; Stangeby, P C

2018-01-01

A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter l p , and the model is thus referred to as the "perimeter sheath expansion method." l p is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ∼ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ∼ 0 and for V = V f .

Assessment of Mining Extent and Expansion in Myanmar Based on Freely-Available Satellite Imagery

Directory of Open Access Journals (Sweden)

Katherine J. LaJeunesse Connette

2016-11-01

Full Text Available Using freely-available data and open-source software, we developed a remote sensing methodology to identify mining areas and assess recent mining expansion in Myanmar. Our country-wide analysis used Landsat 8 satellite data from a select number of mining areas to create a raster layer of potential mining areas. We used this layer to guide a systematic scan of freely-available fine-resolution imagery, such as Google Earth, in order to digitize likely mining areas. During this process, each mining area was assigned a ranking indicating our certainty in correct identification of the mining land use. Finally, we identified areas of recent mining expansion based on the change in albedo, or brightness, between Landsat images from 2002 and 2015. We identified 90,041 ha of potential mining areas in Myanmar, of which 58% (52,312 ha was assigned high certainty, 29% (26,251 ha medium certainty, and 13% (11,478 ha low certainty. Of the high-certainty mining areas, 62% of bare ground was disturbed (had a large increase in albedo since 2002. This four-month project provides the first publicly-available database of mining areas in Myanmar, and it demonstrates an approach for large-scale assessment of mining extent and expansion based on freely-available data.

HISTORICAL FLOOD RISK MANAGEMENT: SPATIAL EXPANSION OF GHERGHIȚA VILLAGE (LOWER PRAHOVA RIVER

Directory of Open Access Journals (Sweden)

IOANA-TOROIMAC GABRIELA

2015-03-01

Full Text Available This paper analyses settlements expansion in flood zones during historical time. We focused on the example of Gherghiţa village on Lower Prahova River by using a diachronic study in GIS. It revealed three major periods of extension of Gherghița village and flood risk management: (1 from Middle Age to the end of the 19th century – prevention against floods by expansion outside the flood-prone area; (2 during the major part of the 20th – flood negligence by expansion inside the flood-prone area; (3 at the end of the 20th century and at the beginning of the 21th century – protection against floods by extension inside the flood-prone area with structural measures (i.e. levees. As a consequence, human pressure on Lower Prahova River grew since the beginning of the 20th century, especially for agricultural purposes.

Negative thermal expansion materials: technological key for control of thermal expansion

OpenAIRE

Koshi Takenaka

2012-01-01

Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K−1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining pra...

14 CFR 139.309 - Safety areas.

Science.gov (United States)

2010-01-01

... construction, reconstruction, or expansion began if construction, reconstruction, or significant expansion of... grading or storm sewers to prevent water accumulation. (3) Each safety area must be capable under dry...

Following Surgically Assisted Rapid Palatal Expansion, Do Tooth-Borne or Bone-Borne Appliances Provide More Skeletal Expansion and Dental Expansion?

Science.gov (United States)

Hamedi-Sangsari, Adrien; Chinipardaz, Zahra; Carrasco, Lee

2017-10-01

The aim of this study was to compare outcome measurements of skeletal and dental expansion with bone-borne (BB) versus tooth-borne (TB) appliances after surgically assisted rapid palatal expansion (SARPE). This study was performed to provide quantitative measurements that will help the oral surgeon and orthodontist in selecting the appliance with, on average, the greatest amount of skeletal expansion and the least amount of dental expansion. A computerized database search was performed using PubMed, EBSCO, Cochrane, Scopus, Web of Science, and Google Scholar on publications in reputable oral surgery and orthodontic journals. A systematic review and meta-analysis was completed with the predictor variable of expansion appliance (TB vs BB) and outcome measurement of expansion (in millimeters). Of 487 articles retrieved from the 6 databases, 5 articles were included, 4 with cone-beam computed tomographic (CBCT) data and 1 with non-CBCT 3-dimensional cast data. There was a significant difference in skeletal expansion (standardized mean difference [SMD], 0.92; 95% confidence interval [CI], 0.54-1.30; P appliances. However, there was no significant difference in dental expansion (SMD, 0.05; 95% CI, -0.24 to 0.34; P = .03). According to the literature, to achieve more effective skeletal expansion and minimize dental expansion after SARPE, a BB appliance should be favored. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography.

Science.gov (United States)

Hirsch, J E

2013-10-01

We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. Copyright © 2013 Elsevier B.V. All rights reserved.

'Thermal ghosts': apparent decay of fixed surfaces caused by heat diffusion

International Nuclear Information System (INIS)

Livadiotis, George

2007-01-01

The behaviour concerning classical heat diffusion on fixed thermal surfaces, studied by observations, still holds surprises. As soon as convective and radiative processes are negligible within the medium, this is considered to be free from energy sources and sinks. Then, the heat diffusion equation is conveniently solved using standard Fourier methods. Some considerations about the contrast effect suggest that the surface boundary would rather be observed to follow specific area decay dynamics than remaining fixed and static. Here it is shown that the apparent boundary lies on a specific isothermal spatiotemporal curve, which depends on the observing device. This is characterized by a slight, though determinative, difference between its radiance and that of the ambient background. Thereafter, the heat diffusion yields apparent boundary shrinkage with the passing of time. This phenomenon is particularly notable for two reasons: its lifetime and final decay rate depend only on the medium thermal properties, while being independent of the apparent boundary spatiotemporal curve. Thus, the former provides a suitable method for measuring the medium thermal properties via the observational data. The latter strongly reveal a kind of universality of some characteristic properties of the phenomenon, common to all observers

Modeling urban expansion in Yangon, Myanmar using Landsat time-series and stereo GeoEye Images

Science.gov (United States)

Sritarapipat, Tanakorn; Takeuchi, Wataru

2016-06-01

This research proposed a methodology to model the urban expansion based dynamic statistical model using Landsat and GeoEye Images. Landsat Time-Series from 1978 to 2010 have been applied to extract land covers from the past to the present. Stereo GeoEye Images have been employed to obtain the height of the building. The class translation was obtained by observing land cover from the past to the present. The height of the building can be used to detect the center of the urban area (mainly commercial area). It was assumed that the class translation and the distance of multi-centers of the urban area also the distance of the roads affect the urban growth. The urban expansion model based on the dynamic statistical model was defined to refer to three factors; (1) the class translation, (2) the distance of the multicenters of the urban areas, and (3) the distance from the roads. Estimation and prediction of urban expansion by using our model were formulated and expressed in this research. The experimental area was set up in Yangon, Myanmar. Since it is the major of country's economic with more than five million population and the urban areas have rapidly increased. The experimental results indicated that our model of urban expansion estimated urban growth in both estimation and prediction steps in efficiency.

Tall shrub expansion facilitated by patterned ground in the northwest Siberian Low Arctic

Science.gov (United States)

Frost, G. V.; Epstein, H. E.; Walker, D. A.; Matyshak, G.; Ermokhina, K.

2011-12-01

We integrated field observations with a time-series of satellite imagery to identify key biophysical attributes associated with tall shrub expansion and increased vegetation productivity within a forest-tundra ecotone near Kharp, northwest Siberia. Comparison of high-resolution Corona and QuickBird satellite photography indicates that alder (Alnus fruticosa) cover increased by ~10% since 1968. Additionally, areas of sharply increasing productivity detected using a Landsat TM/ETM+ time-series for 1985-2009 are consistently co-located with expanding shrub stands. Field observations made in 2011 revealed that most of the shrub expansion has occurred in areas of patterned ground in which abundant mineral-dominated microsites ("circles") have been maintained by cryogenic disturbance. In order to test whether shrub expansion was facilitated by circles, we established a series of transects according to categories of alder stand age and circle density. Along the transects, we mapped the location of alders and circles, measured soil organic depth and leaf area index (LAI), and characterized plant communities. In recent expansion areas, young alders occur almost exclusively on silt-rich circles that lack vegetation and surface organic matter. Alder abundance and LAI increased with the total area occupied by exposed circles. Analyses using spatial statistics indicate that young alders tend to occur in evenly-spaced groups that mirror the spacing of circles. This distribution pattern persists in older alder stands, especially where circles are large and widely-spaced. Stands on closely-spaced circles quickly develop dense canopies and low species-diversity. Based on ground- and satellite-based observations, we conclude that the abundance of mineral-dominated circles at Kharp has facilitated rapid alder expansion and associated alterations in plant community structure, composition, and productivity. Physical processes in areas of patterned ground promote continuous, rather than

Energy-dependent expansion of .177 caliber hollow-point air gun projectiles.

Science.gov (United States)

Werner, Ronald; Schultz, Benno; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias

2017-05-01

Amongst hundreds of different projectiles for air guns available on the market, hollow-point air gun pellets are of special interest. These pellets are characterized by a tip or a hollowed-out shape in their tip which, when fired, makes the projectiles expand to an increased diameter upon entering the target medium. This results in an increase in release of energy which, in turn, has the potential to cause more serious injuries than non-hollow-point projectiles. To the best of the authors' knowledge, reliable data on the terminal ballistic features of hollow-point air gun projectiles compared to standard diabolo pellets have not yet been published in the forensic literature. The terminal ballistic performance (energy-dependent expansion and penetration) of four different types of .177 caliber hollow-point pellets discharged at kinetic energy levels from approximately 3 J up to 30 J into water, ordnance gelatin, and ordnance gelatin covered with natural chamois as a skin simulant was the subject of this investigation. Energy-dependent expansion of the tested hollow-point pellets was observed after being shot into all investigated target media. While some hollow-point pellets require a minimum kinetic energy of approximately 10 J for sufficient expansion, there are also hollow-point pellets which expand at kinetic energy levels of less than 5 J. The ratio of expansion (RE, calculated by the cross-sectional area (A) after impact divided by the cross-sectional area (A 0 ) of the undeformed pellet) of hollow-point air gun pellets reached values up of to 2.2. The extent of expansion relates to the kinetic energy of the projectile with a peak for pellet expansion at the 15 to 20 J range. To conclude, this work demonstrates that the hollow-point principle, i.e., the design-related enlargement of the projectiles' frontal area upon impact into a medium, does work in air guns as claimed by the manufacturers.

Annual cropped area expansion and agricultural production ...

African Journals Online (AJOL)

Ethiopian Journal of Environmental Studies and Management ... considerable annual increase of varying extent over time and space for both annual output and area ... The study suggests improving productivity through sustainable agricultural ...

Expansion of Chiari I-associated syringomyelia after posterior-fossa decompression.

Science.gov (United States)

Gil, Z; Rao, S; Constantini, S

2000-09-01

Chiari I malformation (CMI) is an abnormality that involves caudal herniation of the cerebellar tonsils into the foramen magnum. CMI has been shown to be closely associated with the development of syringomyelia (SM). Several theories have emerged to explain the apparent correlation between the existence of CMI with subsequent development of SM. However, the exact mechanism of the evolution of SM is still subject to controversy. We report here the case of a 12-year-old girl admitted to hospital with headache, vomiting, ataxia, and moderate pyramidal signs. Radiological evaluation revealed the presence of CMI, accompanied by a small SM. The patient underwent posterior fossa decompression and improved significantly. She was re-admitted 6 months later with clinical evidence of progressive spinal cord dysfunction. MR revealed gross expansion of the syrinx. This case raises questions regarding the pathophysiology of CMI and its association with SM. The case indicates the need for neurological and radiological follow-up for patients undergoing posterior fossa decompression due to CMI, even for those without an initial syrinx. This is the first report known to us of expansion of a syrinx following decompression of an associated CMI.

Northward expansion of paddy rice in northeastern Asia during 2000-2014

Science.gov (United States)

Dong, J.; Xiao, X.; Zhang, G.; Menarguez, M. A.; Choi, C. Y.; Qin, Y.; Luo, P.; Zhang, Y.; Moore, B.

2016-04-01

Paddy rice in monsoon Asia plays an important role in global food security and climate change. Here we documented annual dynamics of paddy rice areas in the northern frontier of Asia, including northeastern (NE) China, North Korea, South Korea, and Japan, from 2000 to 2014 through analysis of satellite images. The paddy rice area has increased by 120% (2.5 to 5.5 million ha) in NE China, in comparison to a decrease in South Korea and Japan, and the paddy rice centroid shifted northward from 41.16°N to 43.70°N (~310 km) in this period. Market, technology, policy, and climate together drove the rice expansion in NE China. The increased use of greenhouse nurseries, improved rice cultivars, agricultural subsidy policy, and a rising rice price generally promoted northward paddy rice expansion. The potential effects of large rice expansion on climate change and ecosystem services should be paid more attention to in the future.

Impact of agricultural expansion on water footprint in the Amazon under climate change scenarios

NARCIS (Netherlands)

Miguel Ayala, Laura; Eupen, van Michiel; Zhang, Guoping; Pérez-Soba, Marta; Martorano, Lucieta G.; Lisboa, Leila S.; Beltrao, Norma E.

2016-01-01

Agricultural expansion and intensification are main drivers of land-use change in Brazil. Soybean is the major crop under expansion in the area. Soybean production involves large amounts of water and fertiliser that act as sources of contamination with potentially negative impacts on adjacent

Negative thermal expansion materials

International Nuclear Information System (INIS)

Evans, J.S.O.

1997-01-01

The recent discovery of negative thermal expansion over an unprecedented temperature range in ZrW 2 O 8 (which contracts continuously on warming from below 2 K to above 1000 K) has stimulated considerable interest in this unusual phenomenon. Negative and low thermal expansion materials have a number of important potential uses in ceramic, optical and electronic applications. We have now found negative thermal expansion in a large new family of materials with the general formula A 2 (MO 4 ) 3 . Chemical substitution dramatically influences the thermal expansion properties of these materials allowing the production of ceramics with negative, positive or zero coefficients of thermal expansion, with the potential to control other important materials properties such as refractive index and dielectric constant. The mechanism of negative thermal expansion and the phase transitions exhibited by this important new class of low-expansion materials will be discussed. (orig.)

Negative thermal expansion materials: technological key for control of thermal expansion.

Science.gov (United States)

Takenaka, Koshi

2012-02-01

Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over -30 ppm K -1 . Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade.

Negative thermal expansion materials: technological key for control of thermal expansion

Directory of Open Access Journals (Sweden)

Koshi Takenaka

2012-01-01

Full Text Available Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K−1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade.

Negative thermal expansion materials: technological key for control of thermal expansion

International Nuclear Information System (INIS)

Takenaka, Koshi

2012-01-01

Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K −1 . Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade. (topical review)

Evidence for expansion of the precuneus in human evolution.

Science.gov (United States)

Bruner, Emiliano; Preuss, Todd M; Chen, Xu; Rilling, James K

2017-03-01

The evolution of neurocranial morphology in Homo sapiens is characterized by bulging of the parietal region, a feature unique to our species. In modern humans, expansion of the parietal surface occurs during the first year of life, in a morphogenetic stage which is absent in chimpanzees and Neandertals. A similar variation in brain shape among living adult humans is associated with expansion of the precuneus. Using MRI-derived structural brain templates, we compare medial brain morphology between humans and chimpanzees through shape analysis and geometrical modeling. We find that the main spatial difference is a prominent expansion of the precuneus in our species, providing further evidence of evolutionary changes associated with this area. The precuneus is a major hub of brain organization, a central node of the default-mode network, and plays an essential role in visuospatial integration. Together, the comparative neuroanatomical and paleontological evidence suggest that precuneus expansion is a neurological specialization of H. sapiens that evolved in the last 150,000 years that may be associated with recent human cognitive specializations.

Thermal expansion of coking coals

Energy Technology Data Exchange (ETDEWEB)

Orlik, M.; Klimek, J. (Vyzkumny a Zkusebni Ustav Nova Hut, Ostrava (Czechoslovakia))

1992-12-01

Analyzes expansion of coal mixtures in coke ovens during coking. Methods for measuring coal expansion on both a laboratory and pilot plant scale are comparatively evaluated. The method, developed, tested and patented in Poland by the Institute for Chemical Coal Processing in Zabrze (Polish standard PN-73/G-04522), is discussed. A laboratory device developed by the Institute for measuring coal expansion is characterized. Expansion of black coal from 10 underground mines in the Ostrava-Karvina coal district and from 9 coal mines in the Upper Silesia basin in Poland is comparatively evaluated. Investigations show that coal expansion reaches a maximum for coal types with a volatile matter ranging from 20 to 25%. With increasing volatile matter in coal, its expansion decreases. Coal expansion increases with increasing swelling index. Coal expansion corresponds with coal dilatation. With increasing coal density its expansion increases. Coal mixtures should be selected in such a way that their expansion does not cause a pressure exceeding 40 MPa. 11 refs.

Output Tracking Control of Switched Hybrid Systems: A Fliess Functional Expansion Approach

Directory of Open Access Journals (Sweden)

Fenghua He

2013-01-01

Full Text Available The output tracking problem is investigated for a nonlinear affine system with multiple modes of continuous control inputs. We convert the family of nonlinear affine systems under consideration into a switched hybrid system by introducing a multiple-valued logic variable. The Fliess functional expansion is adopted to express the input and output relationship of the switched hybrid system. The optimal switching control is determined for a multiple-step output tracking performance index. The proposed approach is applied to a multitarget tracking problem for a flight vehicle aiming for one real target with several decoys flying around it in the terminal guidance course. These decoys appear as apparent targets and have to be distinguished with the approaching of the flight vehicle. The guidance problem of one flight vehicle versus multiple apparent targets should be considered if no large miss distance might be caused due to the limitation of the flight vehicle maneuverability. The target orientation at each time interval is determined. Simulation results show the effectiveness of the proposed method.

The frequency-domain approach for apparent density mapping

Science.gov (United States)

Tong, T.; Guo, L.

2017-12-01

Apparent density mapping is a technique to estimate density distribution in the subsurface layer from the observed gravity data. It has been widely applied for geologic mapping, tectonic study and mineral exploration for decades. Apparent density mapping usually models the density layer as a collection of vertical, juxtaposed prisms in both horizontal directions, whose top and bottom surfaces are assumed to be horizontal or variable-depth, and then inverts or deconvolves the gravity anomalies to determine the density of each prism. Conventionally, the frequency-domain approach, which assumes that both top and bottom surfaces of the layer are horizontal, is usually utilized for fast density mapping. However, such assumption is not always valid in the real world, since either the top surface or the bottom surface may be variable-depth. Here, we presented a frequency-domain approach for apparent density mapping, which permits both the top and bottom surfaces of the layer to be variable-depth. We first derived the formula for forward calculation of gravity anomalies caused by the density layer, whose top and bottom surfaces are variable-depth, and the formula for inversion of gravity anomalies for the density distribution. Then we proposed the procedure for density mapping based on both the formulas of inversion and forward calculation. We tested the approach on the synthetic data, which verified its effectiveness. We also tested the approach on the real Bouguer gravity anomalies data from the central South China. The top surface was assumed to be flat and was on the sea level, and the bottom surface was considered as the Moho surface. The result presented the crustal density distribution, which was coinciding well with the basic tectonic features in the study area.

Virial Expansion Bounds

Science.gov (United States)

Tate, Stephen James

2013-10-01

In the 1960s, the technique of using cluster expansion bounds in order to achieve bounds on the virial expansion was developed by Lebowitz and Penrose (J. Math. Phys. 5:841, 1964) and Ruelle (Statistical Mechanics: Rigorous Results. Benjamin, Elmsford, 1969). This technique is generalised to more recent cluster expansion bounds by Poghosyan and Ueltschi (J. Math. Phys. 50:053509, 2009), which are related to the work of Procacci (J. Stat. Phys. 129:171, 2007) and the tree-graph identity, detailed by Brydges (Phénomènes Critiques, Systèmes Aléatoires, Théories de Jauge. Les Houches 1984, pp. 129-183, 1986). The bounds achieved by Lebowitz and Penrose can also be sharpened by doing the actual optimisation and achieving expressions in terms of the Lambert W-function. The different bound from the cluster expansion shows some improvements for bounds on the convergence of the virial expansion in the case of positive potentials, which are allowed to have a hard core.

The relative contributions of forest growth and areal expansion to forest biomass carbon

Science.gov (United States)

P. Li; J. Zhu; H. Hu; Z. Guo; Y. Pan; R. Birdsey; J. Fang

2016-01-01

Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms...

The contribution of mangrove expansion to salt marsh loss on the Texas Gulf Coast.

Science.gov (United States)

Armitage, Anna R; Highfield, Wesley E; Brody, Samuel D; Louchouarn, Patrick

2015-01-01

Landscape-level shifts in plant species distribution and abundance can fundamentally change the ecology of an ecosystem. Such shifts are occurring within mangrove-marsh ecotones, where over the last few decades, relatively mild winters have led to mangrove expansion into areas previously occupied by salt marsh plants. On the Texas (USA) coast of the western Gulf of Mexico, most cases of mangrove expansion have been documented within specific bays or watersheds. Based on this body of relatively small-scale work and broader global patterns of mangrove expansion, we hypothesized that there has been a recent regional-level displacement of salt marshes by mangroves. We classified Landsat-5 Thematic Mapper images using artificial neural networks to quantify black mangrove (Avicennia germinans) expansion and salt marsh (Spartina alterniflora and other grass and forb species) loss over 20 years across the entire Texas coast. Between 1990 and 2010, mangrove area grew by 16.1 km(2), a 74% increase. Concurrently, salt marsh area decreased by 77.8 km(2), a 24% net loss. Only 6% of that loss was attributable to mangrove expansion; most salt marsh was lost due to conversion to tidal flats or water, likely a result of relative sea level rise. Our research confirmed that mangroves are expanding and, in some instances, displacing salt marshes at certain locations. However, this shift is not widespread when analyzed at a larger, regional level. Rather, local, relative sea level rise was indirectly implicated as another important driver causing regional-level salt marsh loss. Climate change is expected to accelerate both sea level rise and mangrove expansion; these mechanisms are likely to interact synergistically and contribute to salt marsh loss.

Parallel search for conjunctions with stimuli in apparent motion.

Science.gov (United States)

Casco, C; Ganis, G

1999-01-01

A series of experiments was conducted to determine whether apparent motion tends to follow the similarity rule (i.e. is attribute-specific) and to investigate the underlying mechanism. Stimulus duration thresholds were measured during a two-alternative forced-choice task in which observers detected either the location or the motion direction of target groups defined by the conjunction of size and orientation. Target element positions were randomly chosen within a nominally defined rectangular subregion of the display (target region). The target region was presented either statically (followed by a 250 ms duration mask) or dynamically, displaced by a small distance (18 min of arc) from frame to frame. In the motion display, the position of both target and background elements was changed randomly from frame to frame within the respective areas to abolish spatial correspondence over time. Stimulus duration thresholds were lower in the motion than in the static task, indicating that target detection in the dynamic condition does not rely on the explicit identification of target elements in each static frame. Increasing the distractor-to-target ratio was found to reduce detectability in the static, but not in the motion task. This indicates that the perceptual segregation of the target is effortless and parallel with motion but not with static displays. The pattern of results holds regardless of the task or search paradigm employed. The detectability in the motion condition can be improved by increasing the number of frames and/or by reducing the width of the target area. Furthermore, parallel search in the dynamic condition can be conducted with both short-range and long-range motion stimuli. Finally, apparent motion of conjunctions is insufficient on its own to support location decision and is disrupted by random visual noise. Overall, these findings show that (i) the mechanism underlying apparent motion is attribute-specific; (ii) the motion system mediates temporal

Attention and apparent motion.

Science.gov (United States)

Horowitz, T; Treisman, A

1994-01-01

Two dissociations between short- and long-range motion in visual search are reported. Previous research has shown parallel processing for short-range motion and apparently serial processing for long-range motion. This finding has been replicated and it has also been found that search for short-range targets can be impaired both by using bicontrast stimuli, and by prior adaptation to the target direction of motion. Neither factor impaired search in long-range motion displays. Adaptation actually facilitated search with long-range displays, which is attributed to response-level effects. A feature-integration account of apparent motion is proposed. In this theory, short-range motion depends on specialized motion feature detectors operating in parallel across the display, but subject to selective adaptation, whereas attention is needed to link successive elements when they appear at greater separations, or across opposite contrasts.

ANALYSIS IMPACT OF THE EXPANSION OF THE REGION AGAINST LOCAL COMMUNITY SOCIAL CONFLICT

Directory of Open Access Journals (Sweden)

Baso Madiong

2016-11-01

Full Text Available Research entitled the influence of the expansion Area of the cultural values of society of West Sulawesi province aims to study the formation mechanism of the new autonomous region, as well as more healt not neglecting the terms that have been determined. and that is not less important is the readiness of the region concerned, both in aspects of the financing, human Resources and the credibility of the bureaucracy in the management of good governance and better. the other thing is to do the capacity of the public to control the performance of the Executive and the legislature which is especially representative of the people who tend to exploit the people. so that the spirit of the sea area bottom line is improving public services and rich people and does not pose a conflict of cultures really manifested in a more benevolent and wise. The method used is the guidance to the Government and society in General about the real purpose of the expansion area as well as coaching the community who are in conflict due to the expansion region.

Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

Science.gov (United States)

Shen, Fei-Ran; Kuang, Hao; Hu, Feng-Xia; Wu, Hui; Huang, Qing-Zhen; Liang, Fei-Xiang; Qiao, Kai-Ming; Li, Jia; Wang, Jing; Liu, Yao; Zhang, Lei; He, Min; Zhang, Ying; Zuo, Wen-Liang; Sun, Ji-Rong; Shen, Bao-Gen

2017-10-01

Materials with zero thermal expansion (ZTE) or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE) materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn-Co-Ge-In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE owing to a martensitic magnetostructural transition. The major finding is that the thermal expansion behavior can be totally controlled by modulating the crystallinity degree and phase transition from atomic scale. Self-compensation effect leads to ultra-low thermal expansion with a linear expansion coefficient as small as +0.68 × 10-6/K over a wide temperature range around room temperature. The present study opens an avenue to reach ZTE particularly from the large class of giant NTE materials based on phase transition.

Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

Directory of Open Access Journals (Sweden)

Fei-Ran Shen

2017-10-01

Full Text Available Materials with zero thermal expansion (ZTE or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn–Co–Ge–In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE owing to a martensitic magnetostructural transition. The major finding is that the thermal expansion behavior can be totally controlled by modulating the crystallinity degree and phase transition from atomic scale. Self-compensation effect leads to ultra-low thermal expansion with a linear expansion coefficient as small as +0.68 × 10−6/K over a wide temperature range around room temperature. The present study opens an avenue to reach ZTE particularly from the large class of giant NTE materials based on phase transition.

THE DEVELOPMENT OF REGIONAL EXPANSION APPARATUS RESOURCE PLACEMENT IN INDONESIA

Directory of Open Access Journals (Sweden)

Suraji

2018-02-01

Full Text Available This study aimed to describe, analyze and deeply assess the implementation of regional apparatus resource development into new areas of regional expansion in Indonesia. The research was conducted by using qualitative approach, specifically, case study by analyzing descriptive data in the form of interviews, as well as analyzing valid data documentation to support the research problem. This research was conducted in the new area of Pangandaran Regency of West Java, Indonesia. The results of the research could map that there were still very few development programs of regional and apparatus expansion and it had not become the priority program after the expansion; the target of improving the quality of the apparatus resource appeared not to be the main measure, but rather, the main measure was the structuring of the apparatus and the issue of the regional office infrastructure; the instruments used in the development and training process were also less supportive, it caused many stagnant employees did not understand about new issues in the dynamics of work; apparatus development through training activities and scientific forums (seminars, scientific discussions, workshops and improvements was obstructed due to budget constraints.

Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

OpenAIRE

Fei-Ran Shen; Hao Kuang; Feng-Xia Hu; Hui Wu; Qing-Zhen Huang; Fei-Xiang Liang; Kai-Ming Qiao; Jia Li; Jing Wang; Yao Liu; Lei Zhang; Min He; Ying Zhang; Wen-Liang Zuo; Ji-Rong Sun

2017-01-01

Materials with zero thermal expansion (ZTE) or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE) materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn–Co–Ge–In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE o...

Two Decades of Negative Thermal Expansion Research: Where Do We Stand?

Science.gov (United States)

Lind, Cora

2012-01-01

Negative thermal expansion (NTE) materials have become a rapidly growing area of research over the past two decades. The initial discovery of materials displaying NTE over a large temperature range, combined with elucidation of the mechanism behind this unusual property, was followed by predictions that these materials will find use in various applications through controlled thermal expansion composites. While some patents have been filed and devices built, a number of obstacles have prevented the widespread implementation of NTE materials to date. This paper reviews NTE materials that contract due to transverse atomic vibrations, their potential for use in controlled thermal expansion composites, and known problems that could interfere with such applications. PMID:28817027

Contrasting patterns of urban expansion in Colombia, Ecuador, Peru, and Bolivia between 1992 and 2009.

Science.gov (United States)

Alvarez-Berríos, Nora L; Parés-Ramos, Isabel K; Aide, T Mitchell

2013-02-01

The global urban population is increasing rapidly, but patterns of urban expansion differ greatly among countries. Urban transition theory predicts that the shift from low to high urbanization depends on a country's history and level of economic development. This study describes urban expansion in Colombia, Ecuador, Peru, and Bolivia between 1992 and 2009. Urban dynamics were analyzed by combining nighttime lights and census data from 4032 municipalities. High-lit areas (>52-63 pixel values) were correlated with urban populations across municipalities and years (R (2) > 0.90). Analyses showed that between 1992 and 2009 Bolivia and Ecuador had rapid population growth and rapidly increasing high-lit areas, while Peru and Colombia had lower rates of population growth and urbanization (i.e., expansion of high-lit areas). We demonstrate how nighttime lights can be a useful tool, providing a homogeneous platform for multi-scale analyses of urban growth.

Thermal expansion of granite rocks

International Nuclear Information System (INIS)

Stephansson, O.

1978-04-01

The thermal expansion of rocks is strongly controlled by the thermal expansion of the minerals. The theoretical thermal expansion of the Stripa Granite is gound to be 21 . 10 -6 [deg C] -1 at 25 deg C and 38 . 10 -6 [deg C] -1 at 400 deg C. The difference in expansion for the rock forming minerals causes micro cracking at heating. The expansion due to micro cracks is found to be of the same order as the mineral expansion. Most of the micro cracks will close at pressures of the order of 10 - 20 MPa. The thermal expansion of a rock mass including the effect of joints is determined in the pilot heater test in the Stripa Mine

Radioprotection considerations on the expansion project of an interim storage facility for radioactive waste

International Nuclear Information System (INIS)

Boni-Mitake, Malvina; Suzuki, Fabio F.; Dellamano, Jose C.

2009-01-01

The Radioactive Waste Management (GRR) of the Nuclear and Energy Research Institute (IPEN/CNEN-SP) receives, treats, packs, characterizes and stores institutional radioactive wastes generated at IPEN-CNEN/SP and also those received from several radiological facilities in the country. The current storage areas have been used to store the treated radioactive waste since the early 1980's and their occupation is close to their full capacity, so a storage area expansion is needed. The expansion project includes the rebuilding of two sheds and the enlargement of the third one in the area currently occupied by the GRR and in a small adjacent area. The civil works will be in controlled area, where the waste management operations will be maintained, so all the steps of this project should be planned and optimized, from the radioprotection point of view. The civil construction will be made in steps. During the project implementation there will be transfer operations of radioactive waste packages to the rebuilt area. After these transfer operations, the civil works will proceed in the vacant areas. This project implies on radiological monitoring, dose control of the involved workers, decontamination and clearance of areas and it is also envisaged the need for repacking of some radioactive waste. The objective this paper is to describe the radioprotection study developed to this expansion project, taking into account the national radioprotection and civil construction regulations. (author)

2015 Plan. Project 1: methodology and planning process of the Brazilian electric sector expansion

International Nuclear Information System (INIS)

1993-10-01

The Planning Process of Brazilian Electric Sector Expansion, their normative aspects, instruments, main agents and the planning cycles are described. The methodology of expansion planning is shown, with the interactions of several study areas, electric power market and the used computer models. The forecasts of methodology evolution is also presented. (C.G.C.)

Ultimate load capacities of expansion anchor bolts

International Nuclear Information System (INIS)

Czarnecki, R.M.; Manrique, M.A.; Samaddar, S.K.

1993-01-01

A summary of available experimental expansion anchor bolt test data is presented. These data were collected as part of programs by the nuclear industry to address generic issues related to verification of seismic adequacy of equipment in nuclear power plants. Some of the data presented are suitable for use in seismic probabilistic risk assessments. For example, mean values of ultimate strength, along with their standard deviation and coefficients of variation, for a range of most typical expansion anchor bolt sizes are presented. Effects of interaction between shear and tension, edge distance, spacing, and cracking of the concrete are presented in a manner that is more suitable for use in deterministic evaluations. Related industry programs to derive anchor bolt capacities are briefly discussed. Recommendations for areas of further investigation are also presented

Current expansion of the Elliot Lake mines

International Nuclear Information System (INIS)

Stenning, G.

1982-06-01

The Elliot Lake mines are located in northern Ontario, on the north shore of Lake Huron. Mining operations in this area started in the mid-1950's and were curtailed during the 1960's. Starting in 1973 Rio Algom's Quirke mine and Denison, the only producers remaining in the area, started to make plans to expand. Increasing production to 30,000 tpd (milled) requires the reopening of the Panel and Stanleigh Mines of the Rio Algom group and the Stanrock-CanMet area at Denison. The first phase of the expansion was preceded by extensive public hearings. Mine production increases, improvement to the facilities at the reopened mines, and the effects on community facilities are described in this paper

Rapid maxillary expansion in contemporary orthodontic literature

Directory of Open Access Journals (Sweden)

Sabrina Mutinelli

2016-01-01

Full Text Available We have reviewed our retrospective research about rapid maxillary expansion performed in the early mixed dentition to summarize the results of different studies regarding maxillary dental arch width variation and crowding improvement in light of contemporary literature. The aim is to define the effects of treatments followed until the end of dental arch growth. In all studies, a Haas expander anchored to the deciduous dentition was used. The samples consisted of treated patients with and without a lateral crossbite and homogeneous untreated individuals as controls. Two additional control groups of adolescents and adults in dental Class 1 were also compared. As a result of the analysis, rapid maxillary expansion with anchorage to the deciduous dentition was found to be effective in increasing transverse width in intermolar and intercanine areas, and the change was preserved until the full permanent dentition stage. When performed before maxillary lateral incisors have fully erupted, this procedure allows for a rapid increase in the arch length in the anterior area and consequently, in the space available for permanent incisors with a stable reduction in crowding over time.

Identification of biomes affected by marginal expansion of agricultural land use induced by increased crop consumption

DEFF Research Database (Denmark)

Kløverpris, Jesper Hedal

2009-01-01

to characterise these areas. The present study ascribes so-called biomes (natural potential vegetation) to the areas affected by agricultural expansion in order to provide a basis for assessing the environmental impacts from land use in the life cycle impact assessment (LCIA). The methodology builds...... on agricultural statistics and maps of global agricultural areas and the global distribution of biomes. The application of the method is illustrated with four examples. The results indicate that agricultural expansion on land suited for crop cultivation (cultivable land) typically affects forest biomes...... or potential grassland/steppe, whereas expansion on land suited for grazing but not for crop cultivation (grazable land) typically occurs on potential shrubland or a few other biomes depending on the region. Some uncertainty applies to the results but it is concluded that it is feasible to identify biomes...

The Role of the Process and Design Variables in Improving the Performance of Heat Exchanger Tube Expansion

Directory of Open Access Journals (Sweden)

Changwan Han

2018-05-01

Full Text Available In the expansion process of a fin-tube heat exchanger, the process variables and shape of the expansion ball affect the deformation of the tube’s inner grooves, the adhesion, and the expansion force. These factors influence the efficiency of heat transfer and the lifetime of the expansion equipment. Therefore, this study analyzed the influential variables of the tube expansion process as well as the expansion ball design through experiments and simulations. A new method was proposed to determine the severity of adhesion in the tube’s inner grooves using the expansion force rate. Expansion experiments with Al tubes show that the expansion force decreases when using a lubricant with high viscosity and when the lubricant remains on the expansion ball for a longer duration. Finite element analysis was also performed to examine the expansion of Cu tubes, which showed that the expansion force was higher when using expansion ball shapes that have higher contact area between the ball and tube surface. The radius of curvature of the expansion ball also influenced the expansion force. However, increasing the ratio of the radial force to the expansion force increased the deformation of the tube’s inner grooves.

Range expansion by Passer montanus in North America

Science.gov (United States)

Burnett, J.L.; Roberts, C.P.; Allen, Craig R.; Brown, M.B.; Moulton, M.P.

2017-01-01

Passer montanus became established in a small area of central North America following its introduction in 1870. P. montanus underwent minimal range expansion in the first 100 years following introduction. However, the North American population of P. montanus is now growing in size and expanding in geographic distribution, having expanded approximately 125 km to the north by 1970. We quantify the distance of spread by P. montanus from its introduction site in the greater St. Louis, Missouri-Illinois, USA area, using distributional (presence) data from the National Audubon Society Christmas Bird Count surveys for the period of 1951 to 2014. Linear regressions of the average annual range center of P. montanus confirmed significant shifts to the north at a rate of 3.3 km/year (P Linear regressions of the linear and angular distance of range center indicates significant northern movement (change in angle of mean range center; P < 0.001) since 1951. Our results quantify the extent of a northward range expansion, and suggesting a probable spread of this species northward.

Effects of emergency department expansion on emergency department patient flow.

Science.gov (United States)

Mumma, Bryn E; McCue, James Y; Li, Chin-Shang; Holmes, James F

2014-05-01

Emergency department (ED) crowding is an increasing problem associated with adverse patient outcomes. ED expansion is one method advocated to reduce ED crowding. The objective of this analysis was to determine the effect of ED expansion on measures of ED crowding. This was a retrospective study using administrative data from two 11-month periods before and after the expansion of an ED from 33 to 53 adult beds in an academic medical center. ED volume, staffing, and hospital admission and occupancy data were obtained either from the electronic health record (EHR) or from administrative records. The primary outcome was the rate of patients who left without being treated (LWBT), and the secondary outcome was total ED boarding time for admitted patients. A multivariable robust linear regression model was used to determine whether ED expansion was associated with the outcome measures. The mean (±SD) daily adult volume was 128 (±14) patients before expansion and 145 (±17) patients after. The percentage of patients who LWBT was unchanged: 9.0% before expansion versus 8.3% after expansion (difference = 0.6%, 95% confidence interval [CI] = -0.16% to 1.4%). Total ED boarding time increased from 160 to 180 hours/day (difference = 20 hours, 95% CI = 8 to 32 hours). After daily ED volume, low-acuity area volume, daily wait time, daily boarding hours, and nurse staffing were adjusted for, the percentage of patients who LWBT was not independently associated with ED expansion (p = 0.053). After ED admissions, ED intensive care unit (ICU) admissions, elective surgical admissions, hospital occupancy rate, ICU occupancy rate, and number of operational ICU beds were adjusted for, the increase in ED boarding hours was independently associated with the ED expansion (p = 0.005). An increase in ED bed capacity was associated with no significant change in the percentage of patients who LWBT, but had an unintended consequence of an increase in ED boarding hours. ED expansion alone does

NICER Detection of Strong Photospheric Expansion during a Thermonuclear X-Ray Burst from 4U 1820–30

Science.gov (United States)

Keek, L.; Arzoumanian, Z.; Chakrabarty, D.; Chenevez, J.; Gendreau, K. C.; Guillot, S.; Güver, T.; Homan, J.; Jaisawal, G. K.; LaMarr, B.; Lamb, F. K.; Mahmoodifar, S.; Markwardt, C. B.; Okajima, T.; Strohmayer, T. E.; in ’t Zand, J. J. M.

2018-04-01

The Neutron Star Interior Composition Explorer (NICER) on the International Space Station (ISS) observed strong photospheric expansion of the neutron star in 4U 1820–30 during a Type I X-ray burst. A thermonuclear helium flash in the star’s envelope powered a burst that reached the Eddington limit. Radiation pressure pushed the photosphere out to ∼200 km, while the blackbody temperature dropped to 0.45 keV. Previous observations of similar bursts were performed with instruments that are sensitive only above 3 keV, and the burst signal was weak at low temperatures. NICER's 0.2–12 keV passband enables the first complete detailed observation of strong expansion bursts. The strong expansion lasted only 0.6 s, and was followed by moderate expansion with a 20 km apparent radius, before the photosphere finally settled back down at 3 s after the burst onset. In addition to thermal emission from the neutron star, the NICER spectra reveal a second component that is well fit by optically thick Comptonization. During the strong expansion, this component is six times brighter than prior to the burst, and it accounts for 71% of the flux. In the moderate expansion phase, the Comptonization flux drops, while the thermal component brightens, and the total flux remains constant at the Eddington limit. We speculate that the thermal emission is reprocessed in the accretion environment to form the Comptonization component, and that changes in the covering fraction of the star explain the evolution of the relative contributions to the total flux.

Resonant state expansions

International Nuclear Information System (INIS)

Lind, P.

1993-02-01

The completeness properties of the discrete set of bound state, virtual states and resonances characterizing the system of a single nonrelativistic particle moving in a central cutoff potential is investigated. From a completeness relation in terms of these discrete states and complex scattering states one can derive several Resonant State Expansions (RSE). It is interesting to obtain purely discrete expansion which, if valid, would significantly simplify the treatment of the continuum. Such expansions can be derived using Mittag-Leffler (ML) theory for a cutoff potential and it would be nice to see if one can obtain the same expansions starting from an eigenfunction theory that is not restricted to a finite sphere. The RSE of Greens functions is especially important, e.g. in the continuum RPA (CRPA) method of treating giant resonances in nuclear physics. The convergence of RSE is studied in simple cases using square well wavefunctions in order to achieve high numerical accuracy. Several expansions can be derived from each other by using the theory of analytic functions and one can the see how to obtain a natural discretization of the continuum. Since the resonance wavefunctions are oscillating with an exponentially increasing amplitude, and therefore have to be interpreted through some regularization procedure, every statement made about quantities involving such states is checked by numerical calculations.Realistic nuclear wavefunctions, generated by a Wood-Saxon potential, are used to test also the usefulness of RSE in a realistic nuclear calculation. There are some fundamental differences between different symmetries of the integral contour that defines the continuum in RSE. One kind of symmetry is necessary to have an expansion of the unity operator that is idempotent. Another symmetry must be used if we want purely discrete expansions. These are found to be of the same form as given by ML. (29 refs.)

Tanshinon IIA injection accelerates tissue expansion by reducing the formation of the fibrous capsule.

Science.gov (United States)

Yu, Qingxiong; Sheng, Lingling; Yang, Mei; Zhu, Ming; Huang, Xiaolu; Li, Qingfeng

2014-01-01

The tissue expansion technique has been applied to obtain new skin tissue to repair large defects in clinical practice. The implantation of tissue expander could initiate a host response to foreign body (FBR), which leads to fibrotic encapsulation around the expander and prolongs the period of tissue expansion. Tanshinon IIA (Tan IIA) has been shown to have anti-inflammation and immunoregulation effect. The rat tissue expansion model was used in this study to observe whether Tan IIA injection systematically could inhibit the FBR to reduce fibrous capsule formation and accelerate the process of tissue expansion. Forty-eight rats were randomly divided into the Tan IIA group and control group with 24 rats in each group. The expansion was conducted twice a week to maintain a capsule pressure of 60 mmHg. The expansion volume and expanded area were measured. The expanded tissue in the two groups was harvested, and histological staining was performed; proinflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) and transforming growth factor-β (TGF-β) were examined. The expansion volume and the expanded area in the Tan IIA group were greater than that of the control group. The thickness of the fibrous capsule in the Tan IIA group was reduced with no influence on the normal skin regeneration. Decreased infiltration of macrophages, lower level of TNF-α, IL-6, IL-1β and TGF-β, less proliferating myofibroblasts and enhanced neovascularization were observed in the Tan IIA group. Our findings indicated that the Tan IIA injection reduced the formation of the fibrous capsule and accelerated the process of tissue expansion by inhibiting the FBR.

Tanshinon IIA injection accelerates tissue expansion by reducing the formation of the fibrous capsule.

Directory of Open Access Journals (Sweden)

Qingxiong Yu

Full Text Available The tissue expansion technique has been applied to obtain new skin tissue to repair large defects in clinical practice. The implantation of tissue expander could initiate a host response to foreign body (FBR, which leads to fibrotic encapsulation around the expander and prolongs the period of tissue expansion. Tanshinon IIA (Tan IIA has been shown to have anti-inflammation and immunoregulation effect. The rat tissue expansion model was used in this study to observe whether Tan IIA injection systematically could inhibit the FBR to reduce fibrous capsule formation and accelerate the process of tissue expansion. Forty-eight rats were randomly divided into the Tan IIA group and control group with 24 rats in each group. The expansion was conducted twice a week to maintain a capsule pressure of 60 mmHg. The expansion volume and expanded area were measured. The expanded tissue in the two groups was harvested, and histological staining was performed; proinflammatory cytokines such as tumor necrosis factor-α (TNF-α, interleukin-6 (IL-6 and interleukin-1β (IL-1β and transforming growth factor-β (TGF-β were examined. The expansion volume and the expanded area in the Tan IIA group were greater than that of the control group. The thickness of the fibrous capsule in the Tan IIA group was reduced with no influence on the normal skin regeneration. Decreased infiltration of macrophages, lower level of TNF-α, IL-6, IL-1β and TGF-β, less proliferating myofibroblasts and enhanced neovascularization were observed in the Tan IIA group. Our findings indicated that the Tan IIA injection reduced the formation of the fibrous capsule and accelerated the process of tissue expansion by inhibiting the FBR.

Deforestation risk due to commodity crop expansion in sub-Saharan Africa

Science.gov (United States)

Ordway, Elsa M.; Asner, Gregory P.; Lambin, Eric F.

2017-04-01

Rapid integration of global agricultural markets and subsequent cropland displacement in recent decades increased large-scale tropical deforestation in South America and Southeast Asia. Growing land scarcity and more stringent land use regulations in these regions could incentivize the offshoring of export-oriented commodity crops to sub-Saharan Africa (SSA). We assess the effects of domestic- and export-oriented agricultural expansion on deforestation in SSA in recent decades. Analyses were conducted at the global, regional and local scales. We found that commodity crops are expanding in SSA, increasing pressure on tropical forests. Four Congo Basin countries, Sierra Leone, Liberia, and Côte d’Ivoire were most at risk in terms of exposure, vulnerability and pressures from agricultural expansion. These countries averaged the highest percent forest cover (58% ± 17.93) and lowest proportions of potentially available cropland outside forest areas (1% ± 0.89). Foreign investment in these countries was concentrated in oil palm production (81%), with a median investment area of 41 582 thousand ha. Cocoa, the fastest expanding export-oriented crop across SSA, accounted for 57% of global expansion in 2000-2013 at a rate of 132 thousand ha yr-1. However, cocoa only amounted to 0.89% of foreign land investment. Commodity crop expansion in SSA appears largely driven by small- and medium-scale farmers rather than industrial plantations. Land-use changes associated with large-scale investments remain to be observed in many countries. Although domestic demand for commodity crops was associated with most agricultural expansion, we provide evidence of a growing influence of distant markets on land-use change in SSA.

Fermions tunneling from apparent horizon of FRW universe

International Nuclear Information System (INIS)

Li Ran; Ren Jirong; Shi Dunfu

2009-01-01

In the paper [R.-G. Cai, L.-M. Cao, Y.-P. Hu, (arXiv: 0809.1554)], the scalar particles' Hawking radiation from the apparent horizon of Friedmann-Robertson-Walker (FRW) universe was investigated by using the tunneling formalism. They obtained the Hawking temperature associated with the apparent horizon, which was extensively applied in investigating the relationship between the first law of thermodynamics and Friedmann equations. In this Letter, we calculate fermions' Hawking radiation from the apparent horizon of FRW universe via tunneling formalism. Applying WKB approximation to the general covariant Dirac equation in FRW spacetime background, the radiation spectrum and Hawking temperature of apparent horizon are correctly recovered, which supports the arguments presented in the paper [R.-G. Cai, L.-M. Cao, Y.-P. Hu, (arXiv: 0809.1554)

A quantitative analysis of craniopharyngioma cyst expansion during and after radiation therapy and surgical implications.

Science.gov (United States)

Lamiman, Kelly; Wong, Kenneth K; Tamrazi, Benita; Nosrati, Jason D; Olch, Arthur; Chang, Eric L; Kiehna, Erin N

2016-12-01

placement of an intracystic catheter for aspiration and delivery of intracystic interferon within 12 months of completing IMRT. All 3 patients now have stable disease. CONCLUSIONS Craniopharyngioma cyst expansion occurred in approximately 40% of the patients during or after radiotherapy. In the majority of patients, cyst expansion was a self-limiting process and did not confer a worse outcome. During radiotherapy, cyst expansion may be apparent on image-guided radiation therapy. Adaptive IMRT planning may be required to ensure that the intended IMRT dose covers the entire tumor and cyst volume. The sequelae of cyst expansion include progressive hydrocephalus, which may be treated with a shunt. For patients with solitary cyst expansion, cyst aspiration and/or intracystic interferon may result in disease control.

Figure-ground segregation modulates apparent motion.

Science.gov (United States)

Ramachandran, V S; Anstis, S

1986-01-01

We explored the relationship between figure-ground segmentation and apparent motion. Results suggest that: static elements in the surround can eliminate apparent motion of a cluster of dots in the centre, but only if the cluster and surround have similar "grain" or texture; outlines that define occluding surfaces are taken into account by the motion mechanism; the brain uses a hierarchy of precedence rules in attributing motion to different segments of the visual scene. Being designated as "figure" confers a high rank in this scheme of priorities.

Isotropic Negative Thermal Expansion Metamaterials.

Science.gov (United States)

Wu, Lingling; Li, Bo; Zhou, Ji

2016-07-13

Negative thermal expansion materials are important and desirable in science and engineering applications. However, natural materials with isotropic negative thermal expansion are rare and usually unsatisfied in performance. Here, we propose a novel method to achieve two- and three-dimensional negative thermal expansion metamaterials via antichiral structures. The two-dimensional metamaterial is constructed with unit cells that combine bimaterial strips and antichiral structures, while the three-dimensional metamaterial is fabricated by a multimaterial 3D printing process. Both experimental and simulation results display isotropic negative thermal expansion property of the samples. The effective coefficient of negative thermal expansion of the proposed models is demonstrated to be dependent on the difference between the thermal expansion coefficient of the component materials, as well as on the circular node radius and the ligament length in the antichiral structures. The measured value of the linear negative thermal expansion coefficient of the three-dimensional sample is among the largest achieved in experiments to date. Our findings provide an easy and practical approach to obtaining materials with tunable negative thermal expansion on any scale.

Urban Expansion and Agricultural Land Loss in China: A Multiscale Perspective

Directory of Open Access Journals (Sweden)

Kaifang Shi

2016-08-01

Full Text Available China’s rapid urbanization has contributed to a massive agricultural land loss that could threaten its food security. Timely and accurate mapping of urban expansion and urbanization-related agricultural land loss can provide viable measures to be taken for urban planning and agricultural land protection. In this study, urban expansion in China from 2001 to 2013 was mapped using the nighttime stable light (NSL, normalized difference vegetation index (NDVI, and water body data. Urbanization-related agricultural land loss during this time period was then evaluated at national, regional, and metropolitan scales by integrating multiple sources of geographic data. The results revealed that China’s total urban area increased from 31,076 km2 in 2001 to 80,887 km2 in 2013, with an average annual growth rate of 13.36%. This widespread urban expansion consumed 33,080 km2 of agricultural land during this period. At a regional scale, the eastern region lost 18,542 km2 or 1.2% of its total agricultural land area. At a metropolitan scale, the Shanghai–Nanjing–Hangzhou (SNH and Pearl River Delta (PRD areas underwent high levels of agricultural land loss with a decrease of 6.12% (4728 km2 and 6.05% (2702 km2 of their total agricultural land areas, respectively. Special attention should be paid to the PRD, with a decline of 13.30% (1843 km2 of its cropland. Effective policies and strategies should be implemented to mitigate urbanization-related agricultural land loss in the context of China’s rapid urbanization.

Cumulus Cell Expansion, Its Role in Oocyte Biology and Perspectives of Measurement: A Review

Directory of Open Access Journals (Sweden)

Nevoral J.

2015-01-01

Full Text Available Cumulus expansion of the cumulus-oocyte complex is necessary for meiotic maturation and acquiring developmental competence. Cumulus expansion is based on extracellular matrix synthesis by cumulus cells. Hyaluronic acid is the most abundant component of this extracellular matrix. Cumulus expansion takes place during meiotic oocyte maturation under in vivo and in vitro conditions. Quantification and measurement of cumulus expansion intensity is one possible method of determining oocyte quality and optimizing conditions for in vitro cultivation. Currently, subjective methods of expanded area and more exact cumulus expansion measurement by hyaluronic acid assessment are available. Among the methods of hyaluronic acid measurement is the use of radioactively labelled synthesis precursors. Alternatively, immunological and analytical methods, including enzyme-linked immunosorbent assay (ELISA, spectrophotometry, and high-performance liquid chromatography (HPLC in UV light, could be utilized. The high sensitivity of these methods could provide a precise analysis of cumulus expansion without the use of radioisotopes. Therefore, the aim of this review is to summarize and compare available approaches of cumulus expansion measurement, respecting special biological features of expanded cumuli, and to suggest possible solutions for exact cumulus expansion analysis.

Annular Internal-External-Expansion Rocket Nozzles for Large Booster Applications

Science.gov (United States)

Connors, James F.; Cubbison, Robert W.; Mitchell, Glenn A.

1961-01-01

For large-thrust booster applications, annular rocket nozzles employing both internal and external expansion are investigated. In these nozzles, free-stream air flows through the center as well as around the outside of the exiting jet. Flaps for deflecting the rocket exhaust are incorporated on the external-expansion surface for thrust-vector control. In order to define nozzle off-design performance, thrust vectoring effectiveness, and external stream effects, an experimental investigation was conducted on two annular nozzles with area ratios of 15 and 25 at Mach 0, 2, and 3 in the Lewis 10- by 10-foot wind tunnel. Air, pressurized to 600 pounds per square inch absolute, was used to simulate the exhaust flow. For a nozzle-pressure-ratio range of 40 to 1000, the ratio of actual to ideal thrust was essentially constant at 0.98 for both nozzles. Compared with conventional convergent-divergent configurations on hypothetical boost missions, the performance gains of the annular nozzle could yield significant orbital payload increases (possibly 8 to 17 percent). A single flap on the external-expansion surface of the area-ratio-25 annular nozzle produced a side force equal to 4 percent of the axial force with no measurable loss in axial thrust.

Does query expansion limit our learning? A comparison of social-based expansion to content-based expansion for medical queries on the internet.

Science.gov (United States)

Pentoney, Christopher; Harwell, Jeff; Leroy, Gondy

2014-01-01

Searching for medical information online is a common activity. While it has been shown that forming good queries is difficult, Google's query suggestion tool, a type of query expansion, aims to facilitate query formation. However, it is unknown how this expansion, which is based on what others searched for, affects the information gathering of the online community. To measure the impact of social-based query expansion, this study compared it with content-based expansion, i.e., what is really in the text. We used 138,906 medical queries from the AOL User Session Collection and expanded them using Google's Autocomplete method (social-based) and the content of the Google Web Corpus (content-based). We evaluated the specificity and ambiguity of the expansion terms for trigram queries. We also looked at the impact on the actual results using domain diversity and expansion edit distance. Results showed that the social-based method provided more precise expansion terms as well as terms that were less ambiguous. Expanded queries do not differ significantly in diversity when expanded using the social-based method (6.72 different domains returned in the first ten results, on average) vs. content-based method (6.73 different domains, on average).

Symmetry in the polarization expansion for intermolecular forces

International Nuclear Information System (INIS)

Chipman, D.M.; Hirschfelder, J.O.

1980-01-01

In the usual polarization expansion for intermolecular forces, exchange effects that determine the separations of energy levels within the manifold of interacting states are ignored. Previous low order calculations on simple physical systems have indicated that these exchange terms can be described reasonably well by an appropriate ad hoc symmetrization of the polarization wave function (the SYM-P method). But theoretical considerations suggest that the SYM-P method should be good for only one of the interacting states and not for the others in the manifold. Here this long standing apparent conflict between theoretical expectations and actual results is explained by consideration of a simple model system in which the relevant equations can be solved exactly. It is concluded that while the SYM-P method is potentially exact for only one of the interacting states, it may provide good approximations to the other states of the manifold in the case of large separations of the interacting subsystems

Apparent directional selection by biased pleiotropic mutation.

Science.gov (United States)

Tanaka, Yoshinari

2010-07-01

Pleiotropic effects of deleterious mutations are considered to be among the factors responsible for genetic constraints on evolution by long-term directional selection acting on a quantitative trait. If pleiotropic phenotypic effects are biased in a particular direction, mutations generate apparent directional selection, which refers to the covariance between fitness and the trait owing to a linear association between the number of mutations possessed by individuals and the genotypic values of the trait. The present analysis has shown how the equilibrium mean value of the trait is determined by a balance between directional selection and biased pleiotropic mutations. Assuming that genes act additively both on the trait and on fitness, the total variance-standardized directional selection gradient was decomposed into apparent and true components. Experimental data on mutation bias from the bristle traits of Drosophila and life history traits of Daphnia suggest that apparent selection explains a small but significant fraction of directional selection pressure that is observed in nature; the data suggest that changes induced in a trait by biased pleiotropic mutation (i.e., by apparent directional selection) are easily compensated for by (true) directional selection.

Multiple pathways of commodity crop expansion in tropical forest landscapes

Science.gov (United States)

Meyfroidt, Patrick; Carlson, Kimberly M.; Fagan, Matthew E.; Gutiérrez-Vélez, Victor H.; Macedo, Marcia N.; Curran, Lisa M.; DeFries, Ruth S.; Dyer, George A.; Gibbs, Holly K.; Lambin, Eric F.; Morton, Douglas C.; Robiglio, Valentina

2014-07-01

Commodity crop expansion, for both global and domestic urban markets, follows multiple land change pathways entailing direct and indirect deforestation, and results in various social and environmental impacts. Here we compare six published case studies of rapid commodity crop expansion within forested tropical regions. Across cases, between 1.7% and 89.5% of new commodity cropland was sourced from forestlands. Four main factors controlled pathways of commodity crop expansion: (i) the availability of suitable forestland, which is determined by forest area, agroecological or accessibility constraints, and land use policies, (ii) economic and technical characteristics of agricultural systems, (iii) differences in constraints and strategies between small-scale and large-scale actors, and (iv) variable costs and benefits of forest clearing. When remaining forests were unsuitable for agriculture and/or policies restricted forest encroachment, a larger share of commodity crop expansion occurred by conversion of existing agricultural lands, and land use displacement was smaller. Expansion strategies of large-scale actors emerge from context-specific balances between the search for suitable lands; transaction costs or conflicts associated with expanding into forests or other state-owned lands versus smallholder lands; net benefits of forest clearing; and greater access to infrastructure in already-cleared lands. We propose five hypotheses to be tested in further studies: (i) land availability mediates expansion pathways and the likelihood that land use is displaced to distant, rather than to local places; (ii) use of already-cleared lands is favored when commodity crops require access to infrastructure; (iii) in proportion to total agricultural expansion, large-scale actors generate more clearing of mature forests than smallholders; (iv) property rights and land tenure security influence the actors participating in commodity crop expansion, the form of land use displacement

Multiple pathways of commodity crop expansion in tropical forest landscapes

International Nuclear Information System (INIS)

Meyfroidt, Patrick; Lambin, Eric F; Carlson, Kimberly M; Fagan, Matthew E; DeFries, Ruth S; Gutiérrez-Vélez, Victor H; Macedo, Marcia N; Curran, Lisa M; Dyer, George A; Gibbs, Holly K; Morton, Douglas C; Robiglio, Valentina

2014-01-01

Commodity crop expansion, for both global and domestic urban markets, follows multiple land change pathways entailing direct and indirect deforestation, and results in various social and environmental impacts. Here we compare six published case studies of rapid commodity crop expansion within forested tropical regions. Across cases, between 1.7% and 89.5% of new commodity cropland was sourced from forestlands. Four main factors controlled pathways of commodity crop expansion: (i) the availability of suitable forestland, which is determined by forest area, agroecological or accessibility constraints, and land use policies, (ii) economic and technical characteristics of agricultural systems, (iii) differences in constraints and strategies between small-scale and large-scale actors, and (iv) variable costs and benefits of forest clearing. When remaining forests were unsuitable for agriculture and/or policies restricted forest encroachment, a larger share of commodity crop expansion occurred by conversion of existing agricultural lands, and land use displacement was smaller. Expansion strategies of large-scale actors emerge from context-specific balances between the search for suitable lands; transaction costs or conflicts associated with expanding into forests or other state-owned lands versus smallholder lands; net benefits of forest clearing; and greater access to infrastructure in already-cleared lands. We propose five hypotheses to be tested in further studies: (i) land availability mediates expansion pathways and the likelihood that land use is displaced to distant, rather than to local places; (ii) use of already-cleared lands is favored when commodity crops require access to infrastructure; (iii) in proportion to total agricultural expansion, large-scale actors generate more clearing of mature forests than smallholders; (iv) property rights and land tenure security influence the actors participating in commodity crop expansion, the form of land use displacement

Analyzing suitability for urban expansion under rapid coastal urbanization with remote sensing and GIS techniques: a case study of Lianyungang, China

Science.gov (United States)

Zhao, Wenjun; Zhu, Xiaodong; Reenberg, Anette; Sun, Xiang

2010-10-01

Beginning in 2000, Lianyungang's urbanization entered a period of rapid growth, spatially as well as economically. Rapid and intensive expansion of "construction land" imposed increasing pressures on regional environment. With the support of remote sensing data and GIS tools, this paper reports a "present-capacity-potential" integrated suitability analysis framework, in order to characterize and evaluate the suitability of urban expansion in Lianyungang. We found that during the rapid coastal urbanization process from 2000 to 2008, the characteristics of physical expansion in the study area were characterized by a combination of high-density expansion and sprawling development. The land use conversion driven by urbanization and industrialization has not occurred only in city districts, but also the surrounding areas that were spatially absorbed by urban growth, while closely associated and greatly influenced by the explosive growth of industrial establishment. The over-consumption of land resources in the areas with low environmental carrying capacity, particularly in the eastern coastal area, should be strictly controlled. Compared to conventional land suitability analysis methods, the proposed integrated approach could better review the potential environmental impacts of urban expansion and provide guidance for decision makers.

Applying the expansion method in hierarchical functions to the solution of Navier-Stokes equations for incompressible fluids

International Nuclear Information System (INIS)

Sabundjian, Gaiane

1999-01-01

This work presents a novel numeric method, based on the finite element method, applied for the solution of the Navier-Stokes equations for incompressible fluids in two dimensions in laminar flow. The method is based on the expansion of the variables in almost hierarchical functions. The used expansion functions are based on Legendre polynomials, adjusted in the rectangular elements in a such a way that corner, side and area functions are defined. The order of the expansion functions associated with the sides and with the area of the elements can be adjusted to the necessary or desired degree. This novel numeric method is denominated by Hierarchical Expansion Method. In order to validate the proposed numeric method three well-known problems of the literature in two dimensions are analyzed. The results show the method capacity in supplying precise results. From the results obtained in this thesis it is possible to conclude that the hierarchical expansion method can be applied successfully for the solution of fluid dynamic problems that involve incompressible fluids. (author)

Urban Expansion and Its Impact on the Land Use Pattern in Xishuangbanna since the Reform and Opening up of China

Directory of Open Access Journals (Sweden)

Hui Cao

2017-02-01

Full Text Available Since the Chinese government carried out the reform and opening up policy, Xishuangbanna Dai Autonomous Prefecture has experienced rapid urbanization and dramatic land use change. This research aims at analyzing urban expansion in Xishuangbanna and its impact on the land use pattern using combined methods, including radar graph, the gradient-direction method and landscape metrics. Seven land use maps from 1976 to 2015 were generated and analyzed, respectively. The results showed that urban and rubber expanded rapidly, while forest decreased during the last 40 years. The city proper, the county town of Menghai and the county town of Mengla showed the most significant and fastest urban expansion rates. In response to rapid urban expansion, land use types outside urban areas changed dramatically. In Jinghong and Mengla, urban areas were usually surrounded by paddy, shrub, rubber and forest in 1976, while most areas were dominated by rubber by 2015. With the development of Xishuangbanna, landscape diversity increased along urban-rural gradients, but decreased in some key urban areas. Urban expansion slightly reduced the connectivity of forest and increased agglomeration of rubber at the same time. Based on the analyses above, we moved forward to discuss the consequences of urban expansion, rubber plantations and land fragmentation.

Standard Test Method for Water Absorption, Bulk Density, Apparent Porosity, and Apparent Specific Gravity of Fired Whiteware Products

CERN Document Server

American Society for Testing and Materials. Philadelphia

2006-01-01

1.1 This test method covers procedures for determining water absorption, bulk density, apparent porosity, and apparent specific gravity of fired unglazed whiteware products. 1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Expansion and Brightness Changes in the Pulsar-wind Nebula in the Composite Supernova Remnant Kes 75

Science.gov (United States)

Reynolds, Stephen P.; Borkowski, Kazimierz J.; Gwynne, Peter H.

2018-04-01

We report new Chandra X-ray observations of the shell supernova remnant Kes 75 (G29.7‑0.3) containing a pulsar and pulsar-wind nebula (PWN). Expansion of the PWN is apparent across four epochs—2000, 2006, 2009, and 2016. We find an expansion rate between 2000 and 2016 of the northwest edge of the PWN of 0.249% ± 0.023% yr‑1, for an expansion age R/(dR/dt) of 400 ± 40 yr and an expansion velocity of about 1000 km s‑1. We suggest that the PWN is expanding into an asymmetric nickel bubble in a conventional Type IIP supernova. Some acceleration of the PWN expansion is likely, giving a true age of 480 ± 50 yr. The pulsar’s birth luminosity was larger than the current value by a factor of 3–8, while the initial period was within a factor of 2 of its current value. We confirm directly that Kes 75 contains the youngest known PWN, and hence the youngest known pulsar. The pulsar PSR J1846‑0258 has a spindown-inferred magnetic field of 5 × 1013 G; in 2006, it emitted five magnetar-like short X-ray bursts, but its spindown luminosity has not changed significantly. However, the flux of the PWN has decreased by about 10% between 2009 and 2016, almost entirely in the northern half. A bright knot has declined by 30% since 2006. During this time, the photon indices of the power-law models did not change. This flux change is too rapid to be due to normal PWN evolution in one-zone models.

Multiple Weather Factors Affect Apparent Survival of European Passerine Birds

Science.gov (United States)

Salewski, Volker; Hochachka, Wesley M.; Fiedler, Wolfgang

2013-01-01

Weather affects the demography of animals and thus climate change will cause local changes in demographic rates. In birds numerous studies have correlated demographic factors with weather but few of those examined variation in the impacts of weather in different seasons and, in the case of migrants, in different regions. Using capture-recapture models we correlated weather with apparent survival of seven passerine bird species with different migration strategies to assess the importance of selected facets of weather throughout the year on apparent survival. Contrary to our expectations weather experienced during the breeding season did not affect apparent survival of the target species. However, measures for winter severity were associated with apparent survival of a resident species, two short-distance/partial migrants and a long-distance migrant. Apparent survival of two short distance migrants as well as two long-distance migrants was further correlated with conditions experienced during the non-breeding season in Spain. Conditions in Africa had statistically significant but relatively minor effects on the apparent survival of the two long-distance migrants but also of a presumably short-distance migrant and a short-distance/partial migrant. In general several weather effects independently explained similar amounts of variation in apparent survival for the majority of species and single factors explained only relatively low amounts of temporal variation of apparent survival. Although the directions of the effects on apparent survival mostly met our expectations and there are clear predictions for effects of future climate we caution against simple extrapolations of present conditions to predict future population dynamics. Not only did weather explains limited amounts of variation in apparent survival, but future demographics will likely be affected by changing interspecific interactions, opposing effects of weather in different seasons, and the potential for

APPLING REMOTE SENSING TECHNIQUE TO MONITORING SPATIAL EXPANSION OF IMPORTANT CITIES IN CHINA-INDOCHINA PENINSULA ECONOMIC CORRIDOR

Directory of Open Access Journals (Sweden)

J. Li

2017-09-01

Full Text Available Since twentieth Century, the process of economic globalization has made great progress, and Southeast Asia has developed rapidly under the background of international industrial transferring. In this paper, the 6 important nodes cities in China - Indochina Peninsula along the economic corridor are took as study area. The main data is time series Landsat data. The method of object-oriented random forest classification was used to extract the classification results of study area from 2000 to 2015. The urban expansion of the node cities was evaluated by calculating the expansion speed of the impervious surface and the landscape pattern metrics. The results indicated that the method of object oriented random forest classification can effectively extract the urban impervious surface. the overall accuracy is over 81 %, and the Kappa coefficient is over 0.82. In the past 15 years, the expansion speed of Vientiane city was fastest in 6 countries. The area of urban impervious surface expanded 8 times than that of 2000.The pattern of expansion is summarized as “gather first-diffuse then”, “diffuse first-gather then” and “gather”. Overall, the process of urbanization of these cities are still in the rising period.

Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion

Directory of Open Access Journals (Sweden)

Marquardt C

2009-11-01

Full Text Available Abstract Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present.

The sugarcane-biofuel expansion and dairy farmers' responses in Brazil

NARCIS (Netherlands)

Monteiro Novo, A.L.; Jansen, K.; Slingerland, M.A.

2012-01-01

The expansion of sugarcane for biofuels is a highly contentious issue. The growth of sugarcane area has occurred simultaneously with a reduction of dairy production in São Paulo state, the primary production region for sugar and ethanol in Brazil. This paper analyses different dairy farm rationales

Energy expansion planning by considering electrical and thermal expansion simultaneously

International Nuclear Information System (INIS)

Abbasi, Ali Reza; Seifi, Ali Reza

2014-01-01

Highlights: • This paper focused on the expansion planning optimization of energy systems. • Employing two form of energy: the expansion of electrical and thermal energies. • The main objective is to minimize the costs. • A new Modified Honey Bee Mating Optimization (MHBMO) algorithm is applied. - Abstract: This study focused on the expansion planning optimization of energy systems employing two forms of energy: the expansion of electrical and thermal energies simultaneously. The main objective of this investigation is confirming network adequacy by adding new equipment to the network, over a given planning horizon. The main objective of the energy expansion planning (EEP) is to minimize the real energy loss, voltage deviation and the total cost of installation equipments. Since the objectives are different and incommensurable, it is difficult to solve the problem by the conventional approaches that may optimize a single objective. So, the meta-heuristic algorithm is applied to this problem. Here, Honey Bee Mating Optimization algorithm (HBMO) as a new evolutionary optimization algorithm is utilized. In order to improve the total ability of HBMO for the global search and exploration, a new modification process is suggested such a way that the algorithm will search the total search space globally. Also, regarding the uncertainties of the new complicated energy systems, in this paper for the first time, the EEP problem is investigated in a stochastic environment by the use of probabilistic load flow technique based on Point Estimate Method (PEM). In order to evaluate the feasibility and effectiveness of the proposed algorithm, two modified test systems are used as case studies

An incentive mechanism for electricity transmission expansion in Mexico

International Nuclear Information System (INIS)

Rosellon, Juan

2007-01-01

This study proposes an incentive regulatory framework for expanding electricity transmission in Mexico. A two-part pricing model is implemented within a combined merchant-regulatory structure. Three cases are considered. In the first, a monopolist with 'postage stamp tariffs' serves the whole country using uniform prices. In the second case, one firm holds a regional monopoly in each of the five electricity areas. In the third, a monopolist operates in all areas of the national electricity system and discriminates in the prices it charges in each of the regions. This approach is described and then applied to the Mexican electricity transmission network. Using real data, the study compares all three cases in terms of profits, capacity increases, and network expansion. The results are found to depend on two effects: the 'economies-of-scale effect', in which the maximum level is reached with a single network; and the 'discriminatory effect' that results when a firm can discriminate among types of consumers. The economies-of-scale effect produces greater capacity and network expansion, whereas the discriminatory effect increases profits

Apparent Solar Tornado-Like Prominences

Science.gov (United States)

Panasenco, Olga; Martin, Sara F.; Velli, Marco

2014-02-01

Recent high-resolution observations from the Solar Dynamics Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado-like prominences. This class of prominences was first introduced by Pettit ( Astrophys. J. 76, 9, 1932), who studied them over many years. Observations of tornado prominences similar to the ones seen by SDO had already been documented by Secchi ( Le Soleil, 1877). High-resolution and high-cadence multiwavelength data obtained by SDO reveal that the tornado-like appearance of these prominences is mainly an illusion due to projection effects. We discuss two different cases where prominences on the limb might appear to have a tornado-like behavior. One case of apparent vortical motions in prominence spines and barbs arises from the (mostly) 2D counterstreaming plasma motion along the prominence spine and barbs together with oscillations along individual threads. The other case of apparent rotational motion is observed in a prominence cavity and results from the 3D plasma motion along the writhed magnetic fields inside and along the prominence cavity as seen projected on the limb. Thus, the "tornado" impression results either from counterstreaming and oscillations or from the projection on the plane of the sky of plasma motion along magnetic-field lines, rather than from a true vortical motion around an (apparent) vertical or horizontal axis. We discuss the link between tornado-like prominences, filament barbs, and photospheric vortices at their base.

Paddy Field Expansion and Aggregation Since the Mid-1950s in a Cold Region and Its Possible Causes

Directory of Open Access Journals (Sweden)

Fengqin Yan

2018-03-01

Full Text Available Over the last six decades, paddy fields on the Sanjiang Plain have experienced rapid expansion and aggregation. In our study, land use and land cover changes related to paddy fields were studied based on information acquired from topographic maps and remote-sensing images. Paddy field expansion and aggregation were investigated through landscape indices and trajectory codes. Furthermore, the possible causes of paddy field expansion and aggregation were explored. Results indicated that such fields have increased by approximately 42,704 ha·y−1 over the past six decades. Approximately 98% of paddy fields in 2015 were converted from other land use types. In general, the gravity center moved 254.51 km toward the northeast, at a rate of approximately 4.17 km·y−1. The cohesion index increased from 96.8208 in 1954 to 99.5656 in 2015, and the aggregation index grew from 91.3533 in 1954 to 93.4448 in 2015, indicating the apparent aggregation of paddy fields on the Sanjiang Plain. Trajectory analyses showed that the transformations from marsh as well as from grassland to dry farmland and then into paddy fields were predominant. Climate warming provided a favorable environment for rice planting. Meanwhile, population growth, technological progress, and government policies drove paddy field expansion and aggregation during the study period.

The Role of Remote Sensing for Understanding Large-Scale Rubber Concession Expansion in Southern Laos

Directory of Open Access Journals (Sweden)

Mutlu Özdoğan

2018-04-01

Full Text Available Increasing global demand for natural rubber began in the mid-2000s and led to large-scale expansion of plantations in Laos until rubber latex prices declined greatly beginning in 2011. The expansion of rubber did not, however, occur uniformly across the country. While the north and central Laos experienced mostly local and smallholder plantations, rubber expansion in the south was dominated by transnational companies from Vietnam, China and Thailand through large-scale land concessions, often causing conflicts with local communities. In this study we use satellite remote sensing to identify and map the expansion of large-scale rubber plantations in Champasak Province—the first area in southern Laos to host large-scale rubber development—and document the biophysical impacts on the local landscape, which of course is linked to social impacts on local people. Our study demonstrates that the expansion of rubber in the province was rapid and did not always conform to approved concession area locations. The mono-culture nature of rubber plantations also had the effect of homogenizing the landscape, eclipsing the changes caused by local populations. We argue that by providing a relatively inexpensive way to track the expansion of rubber plantations over space and time, remote sensing has the potential to provide advocates and other civil society groups with data that might otherwise remain limited to the restricted domains of state regulation and private sector reporting. However, we also caution that while remote sensing has the potential to provide strong public evidence about plantation expansion, access to and control of this information ultimately determines its value.

FRACTAL DIMENSION OF URBAN EXPANSION BASED ON REMOTE SENSING IMAGES

Directory of Open Access Journals (Sweden)

IACOB I. CIPRIAN

2012-11-01

Full Text Available Fractal Dimension of Urban Expansion Based on Remote Sensing Images: In Cluj-Napoca city the process of urbanization has been accelerated during the years and implication of local authorities reflects a relevant planning policy. A good urban planning framework should take into account the society demands and also it should satisfy the natural conditions of local environment. The expansion of antropic areas it can be approached by implication of 5D variables (time as a sequence of stages, space: with x, y, z and magnitude of phenomena into the process, which will allow us to analyse and extract the roughness of city shape. Thus, to improve the decision factor we take a different approach in this paper, looking at geometry and scale composition. Using the remote sensing (RS and GIS techniques we manage to extract a sequence of built-up areas (from 1980 to 2012 and used the result as an input for modelling the spatialtemporal changes of urban expansion and fractal theory to analysed the geometric features. Taking the time as a parameter we can observe behaviour and changes in urban landscape, this condition have been known as self-organized – a condition which in first stage the system was without any turbulence (before the antropic factor and during the time tend to approach chaotic behaviour (entropy state without causing an disequilibrium in the main system.

Expansion joints for LMFBR

International Nuclear Information System (INIS)

Dzenus, M.; Hundhausen, W.; Jansing, W.

1980-01-01

This discourse recounts efforts put into the SNR-2 project; specifically the development of compensation devices. The various prototypes of these compensation devices are described and the state of the development reviewed. Large Na (sodium)-heat transfer systems require a lot of valuable space if the component lay-out does not include compensation devices. So, in order to condense the spatial requirement as much as possible, expansion joints must be integrated into the pipe system. There are two basic types to suit the purpose: axial expansion joints and angular expansion joints. The expansion joints were developed on the basis of specific design criteria whereby differentiation is made between expansion joints of small and large nominal diameter. Expansion joints for installation in the sodium-filled primary piping are equipped with safety bellows in addition to the actual working bellows. Expansion joints must be designed and mounted in a manner to completely withstand seismic forces. The design must exclude any damage to the bellows during intermittent operations, that is, when sodium is drained the bellows' folds must be completely empty; otherwise residual solidified sodium could destroy the bellows when restarting. The expansion joints must be engineered on the basis of the following design data for the secondary system of the SNR project: working pressure: 16 bar; failure mode pressure: 5 events; failure mode: 5 sec., 28.5 bar, 520 deg. C; working temperature: 520 deg. C; temperature transients: 30 deg. C/sec.; service life: 200,000 h; number of load cycles: 10 4 ; material: 1.4948 or 1.4919; layer thickness of folds: 0.5 mm; angular deflection (DN 800): +3 deg. C or; axial expansion absorption (DN 600): ±80 mm; calculation: ASME class. The bellows' development work is not handled within this scope. The bellows are supplied by leading manufacturers, and warrant highest quality. Multiple bellows were selected on the basis of maximum elasticity - a property

Multi area and multistage expansion-planning of electricity supply with sustainable energy development criteria: a multi objective model

Energy Technology Data Exchange (ETDEWEB)

Unsihuay-Vila, Clodomiro; Marangon-Lima, J.W.; Souza, A.C Zambroni de [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)], emails: clodomirounsihuayvila @gmail.com, marangon@unifei.edu.br, zambroni@unifei.edu.br; Perez-Arriaga, I.J. [Universidad Pontificia Comillas, Madrid (Spain)], email: ipa@mit.edu

2010-07-01

A novel multi objective, multi area and multistage model to long-term expansion-planning of integrated generation and transmission corridors incorporating sustainable energy developing is presented in this paper. The proposed MESEDES model is a multi-regional multi-objective and 'bottom-up' energy model which considers the electricity generation/transmission value-chain, i.e., power generation alternatives including renewable, nuclear and traditional thermal generation along with transmission corridors. The model decides the optimal location and timing of the electricity generation/transmission abroad the multistage planning horizon. The MESEDES model considers three objectives belonging to sustainable energy development criteria such as: a) the minimization of investments and operation costs of : power generation, transmission corridors, energy efficiency (demand side management (DSM) programs) considering CO2 capture technologies; b) minimization of Life Cycle Greenhouse Gas Emissions (LC GHG); c) maximization of the diversification of electricity generation mix. The proposed model consider aspects of the carbon abatement policy under the CDM - Clean Development Mechanism or European Union Greenhouse Gas Emission Trading Scheme. A case study is used to illustrate the proposed framework. (author)

Expansion joints for LMFBR

Energy Technology Data Exchange (ETDEWEB)

Dzenus, M.; Hundhausen, W.; Jansing, W.

1979-10-15

This discourse recounts efforts put into the SNR-2 project; specifically the development of compensation devices. The various prototypes of these compensation devices are described and the state of development reviewed. The expansion joints were developed on the basis of specific design criteria whereby differentiation is made between expansion joints of small and large nominal diameter. Expansion joints for installation in the sodium-filled primary piping are equipped with safety bellows in addition to the actual working bellows.

Occurance and expansion: if it was not so?

Directory of Open Access Journals (Sweden)

Ratnikov Viatcheslav Yurievich

2013-10-01

Full Text Available The author criticizes some hypotheses of amphibians and reptiles occurrence and expansion, including those on the basis of data phylogeography interpretation,suggested by herpetologists. Using molecular data, it is impossible to define, where subspecies has appeared and how its area varied. The method of definition of species appearance time requires very serious correlation by means of paleontological data. It is also impossible to identify approximate time of the subspecies occurrence, defined by molecular data, with the time of its modern area occupation. We can assume it, analyzing paleontological findings and paleogeographical conditions at that time, but not vice versa.

Improved vertical displacements induced by a refined thermal expansion model and its quantitative analysis in GPS height time series

Science.gov (United States)

Wang, Kaihua; Chen, Hua; Jiang, Weiping; Li, Zhao; Ma, Yifang; Deng, Liansheng

2018-04-01

There are apparent seasonal variations in GPS height time series, and thermal expansion is considered to be one of the potential geophysical contributors. The displacements introduced by thermal expansion are usually derived without considering the annex height and underground part of the monument (e.g. located on roof or top of the buildings), which may bias the geophysical explanation of the seasonal oscillation. In this paper, the improved vertical displacements are derived by a refined thermal expansion model where the annex height and underground depth of the monument are taken into account, and then 560 IGS stations are adopted to validate the modeled thermal expansion (MTE) displacements. In order to evaluate the impact of thermal expansion on GPS heights, the MTE displacements of 80 IGS stations with less data discontinuities are selected to compare with their observed GPS vertical (OGV) displacements with the modeled surface loading (MSL) displacements removed in advance. Quantitative analysis results show the maximum annual and semiannual amplitudes of the MTE are 6.65 mm (NOVJ) and 0.51 mm (IISC), respectively, and the maximum peak-to-peak oscillation of the MTE displacements can be 19.4 mm. The average annual amplitude reductions are 0.75 mm and 1.05 mm respectively after removing the MTE and MSL displacements from the OGV, indicating the seasonal oscillation induced by thermal expansion is equivalent to >75% of the impact of surface loadings. However, there are rarely significant reductions for the semiannual amplitude. Given the result in this study that thermal expansion can explain 17.3% of the annual amplitude in GPS heights on average, it must be precisely modeled both in GPS precise data processing and GPS time series analysis, especially for those stations located in the middle and high latitudes with larger annual temperature oscillation, or stations with higher monument.

Influences of Urban Expansion on Cultivated Lands in China Since 1970S

Science.gov (United States)

Liu, F.; Zhang, Z.; Zhao, X.; Yu, S.; Wang, X.; Zuo, L.

2018-04-01

Urban expansion has far-reaching influences on cultivated lands, and has a serious effect on grain output and safety. However, relatively little attention has been paid to monitor cultivated land losses through urban expansion over a long timeframe and multi-frequency, especially its differences on national scale systematically. In this work, the characteristics of Chinese cultivated land dynamics were described using annual occupied area per city, contribution rate of cultivated lands to urban expansion and the classification method of basic trend of cultivated land losses. Results indicate that: (1) in the past four decades, large amount of cultivated lands have been occupied during the urban expansion process, and have become the first land source for Chinese urban expansion. (2) Cultivated land loss among municipalities, provincial capitals and other cities was obviously different. The higher of cities' administrative level was, the more obvious of cultivated land loss in these cities appeared, and the earlier of acceleration loss stage of cultivated lands occurred. (3) Cultivated land loss in five population-size cities was unbalanced, representing obviously different loss process and contribution on urban expansion. The bigger of cities' population size was, the more obvious of cultivated land loss in these cities appeared, and the earlier of acceleration loss stage of cultivated lands occurred. (4) Cultivated land losses during urban expansion process were imbalanced in China, and were classified into seven trends. (5) Chinese cultivated land protection has been carried out from the awakening stage to the deep implementation stage.

Inhibitory Effect of Waste Glass Powder on ASR Expansion Induced by Waste Glass Aggregate

Directory of Open Access Journals (Sweden)

Shuhua Liu

2015-10-01

Full Text Available Detailed research is carried out to ascertain the inhibitory effect of waste glass powder (WGP on alkali-silica reaction (ASR expansion induced by waste glass aggregate in this paper. The alkali reactivity of waste glass aggregate is examined by two methods in accordance with the China Test Code SL352-2006. The potential of WGP to control the ASR expansion is determined in terms of mean diameter, specific surface area, content of WGP and curing temperature. Two mathematical models are developed to estimate the inhibitory efficiency of WGP. These studies show that there is ASR risk with an ASR expansion rate over 0.2% when the sand contains more than 30% glass aggregate. However, WGP can effectively control the ASR expansion and inhibit the expansion rate induced by the glass aggregate to be under 0.1%. The two mathematical models have good simulation results, which can be used to evaluate the inhibitory effect of WGP on ASR risk.

Expansions for Coulomb wave functions

NARCIS (Netherlands)

Boersma, J.

1969-01-01

In this paper we derive a number of expansions for Whittaker functions, regular and irregular Coulomb wave functions. The main result consists of a new expansion for the irregular Coulomb wave functions of orders zero and one in terms of regular Coulomb wave functions. The latter expansions are

6th International Symposium on Thermal Expansion

CERN Document Server

1978-01-01

This 6th International Symposium on Thermal Expansion, the first outside the USA, was held on August 29-31, 1977 at the Gull Harbour Resort on Hecla Island, Manitoba, Canada. Symposium Chairman was Ian D. Peggs, Atomic Energy of Canada Limited, and our continuing sponsor was CINDAS/Purdue University. We made considerable efforts to broaden the base this year to include more users of expansion data but with little success. We were successful, however, in establishing a session on liquids, an area which is receiving more attention as a logical extension to the high-speed thermophysical property measurements on materials at temperatures close to their melting points. The Symposium had good international representation but the overall attendance was, disappointingly, relatively low. Neverthe­ less, this enhanced the informal atmosphere throughout the meeting with a resultant frank exchange of information and ideas which all attendees appreciated. A totally new item this year was the presentation of a bursary to ...

LAND USE EVOLUTION AND GEOMORPHOLOGICAL UNIT RELATIONSHIP IN RIACHÃO DAS NEVES COUNTY (BA: EFFECTS IN PROTECTED AREAS

Directory of Open Access Journals (Sweden)

Rosana Sumiya Gurgel

2013-07-01

Full Text Available The appropriation of the natural environment by man establishes strategies of spatial production and organization. This work aims to perform a multitemporal analysis of land use and land cover in the last two decades in Riachão das Neves County, considering the terrain attributes and the adequacy of environmental laws. The methodology adopts remote sensing and GIS techniques and field work. The data processing can be subdivided into the following steps: (a multitemporal analysis of agricultural expansion, (b protected areas mapping, and (c identification of inappropriate use of protected areas. Multitemporal analysis using ALOS-PRISM sensor with high spatial resolution for 2008 and the Landsat imagery from 1988, 1992, 1996, 2000, 2004 and 2008. The classification process was done by visual interpretation and checking of field work. Riachão das Neves has approximately 67% of the natural vegetation. There is an apparent geomorphological control on the production system. In the Depression and Valley areas, the land use is concentrated around the rivers by small farmers, mostly livestock farming, while in the Plateau areas the land use is dominated by large scale mechanized agriculture.

Nuclear deformation and expression change of cartilaginous genes during in vitro expansion of chondrocytes

International Nuclear Information System (INIS)

Hoshiba, Takashi; Yamada, Tomoe; Lu, Hongxu; Kawazoe, Naoki; Tateishi, Tetsuya; Chen, Guoping

2008-01-01

Cartilaginous gene expression decreased when chondrocytes were expanded on cell-culture plates. Understanding the dedifferentiation mechanism may provide valuable insight into cartilage tissue engineering. Here, we demonstrated the relationship between the nuclear shape and gene expression during in vitro expansion culture of chondrocytes. Specifically, the projected nuclear area increased and cartilaginous gene expressions decreased during in vitro expansion culture. When the nuclear deformation was recovered by cytochalasin D treatment, aggrecan expression was up-regulated and type I collagen (Col1a2) expression was down-regulated. These results suggest that nuclear deformation may be one of the mechanisms for chondrocyte dedifferentiation during in vitro expansion culture

Multistage and multiobjective formulations of globally optimal upgradable expansions for electric power distribution systems

Science.gov (United States)

Vaziri Yazdi Pin, Mohammad

Electric power distribution systems are the last high voltage link in the chain of production, transport, and delivery of the electric energy, the fundamental goals of which are to supply the users' demand safely, reliably, and economically. The number circuit miles traversed by distribution feeders in the form of visible overhead or imbedded underground lines, far exceed those of all other bulk transport circuitry in the transmission system. Development and expansion of the distribution systems, similar to other systems, is directly proportional to the growth in demand and requires careful planning. While growth of electric demand has recently slowed through efforts in the area of energy management, the need for a continued expansion seems inevitable for the near future. Distribution system and expansions are also independent of current issues facing both the suppliers and the consumers of electrical energy. For example, deregulation, as an attempt to promote competition by giving more choices to the consumers, while it will impact the suppliers' planning strategies, it cannot limit the demand growth or the system expansion in the global sense. Curiously, despite presence of technological advancements and a 40-year history of contributions in the area, many of the major utilities still relay on experience and resort to rudimentary techniques when planning expansions. A comprehensive literature review of the contributions and careful analyses of the proposed algorithms for distribution expansion, confirmed that the problem is a complex, multistage and multiobjective problem for which a practical solution remains to be developed. In this research, based on the 15-year experience of a utility engineer, the practical expansion problem has been clearly defined and the existing deficiencies in the previous work identified and analyzed. The expansion problem has been formulated as a multistage planning problem in line with a natural course of development and industry

Conformal expansions and renormalons

Energy Technology Data Exchange (ETDEWEB)

Rathsman, J.

2000-02-07

The coefficients in perturbative expansions in gauge theories are factorially increasing, predominantly due to renormalons. This type of factorial increase is not expected in conformal theories. In QCD conformal relations between observables can be defined in the presence of a perturbative infrared fixed-point. Using the Banks-Zaks expansion the authors study the effect of the large-order behavior of the perturbative series on the conformal coefficients. The authors find that in general these coefficients become factorially increasing. However, when the factorial behavior genuinely originates in a renormalon integral, as implied by a postulated skeleton expansion, it does not affect the conformal coefficients. As a consequence, the conformal coefficients will indeed be free of renormalon divergence, in accordance with previous observations concerning the smallness of these coefficients for specific observables. The authors further show that the correspondence of the BLM method with the skeleton expansion implies a unique scale-setting procedure. The BLM coefficients can be interpreted as the conformal coefficients in the series relating the fixed-point value of the observable with that of the skeleton effective charge. Through the skeleton expansion the relevance of renormalon-free conformal coefficients extends to real-world QCD.

Bearing-Mounting Concept Accommodates Thermal Expansion

Science.gov (United States)

Nespodzany, Robert; Davis, Toren S.

1995-01-01

Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools.

Science.gov (United States)

Seto, Karen C; Güneralp, Burak; Hutyra, Lucy R

2012-10-02

Urban land-cover change threatens biodiversity and affects ecosystem productivity through loss of habitat, biomass, and carbon storage. However, despite projections that world urban populations will increase to nearly 5 billion by 2030, little is known about future locations, magnitudes, and rates of urban expansion. Here we develop spatially explicit probabilistic forecasts of global urban land-cover change and explore the direct impacts on biodiversity hotspots and tropical carbon biomass. If current trends in population density continue and all areas with high probabilities of urban expansion undergo change, then by 2030, urban land cover will increase by 1.2 million km(2), nearly tripling the global urban land area circa 2000. This increase would result in considerable loss of habitats in key biodiversity hotspots, with the highest rates of forecasted urban growth to take place in regions that were relatively undisturbed by urban development in 2000: the Eastern Afromontane, the Guinean Forests of West Africa, and the Western Ghats and Sri Lanka hotspots. Within the pan-tropics, loss in vegetation biomass from areas with high probability of urban expansion is estimated to be 1.38 PgC (0.05 PgC yr(-1)), equal to ∼5% of emissions from tropical deforestation and land-use change. Although urbanization is often considered a local issue, the aggregate global impacts of projected urban expansion will require significant policy changes to affect future growth trajectories to minimize global biodiversity and vegetation carbon losses.

7 CFR 1940.959 - Area plan.

Science.gov (United States)

2010-01-01

..., and time lines based on a realistic assessment of the area, including, but not limited to, the... possibilities for industrial recruitment in the area; (5) The potential for development of tourism in the area... expansion of existing businesses; and (7) The potential to produce value-added agricultural products in the...

Integrated thermal infrared imaging and Structure-from-Motion photogrametry to map apparent temperature and radiant hydrothermal heat flux at Mammoth Mountain, CA USA

Science.gov (United States)

Lewis, Aaron; George Hilley,; Lewicki, Jennifer L.

2015-01-01

This work presents a method to create high-resolution (cm-scale) orthorectified and georeferenced maps of apparent surface temperature and radiant hydrothermal heat flux and estimate the radiant hydrothermal heat emission rate from a study area. A ground-based thermal infrared (TIR) camera was used to collect (1) a set of overlapping and offset visible imagery around the study area during the daytime and (2) time series of co-located visible and TIR imagery at one or more sites within the study area from pre-dawn to daytime. Daytime visible imagery was processed using the Structure-from-Motion photogrammetric method to create a digital elevation model onto which pre-dawn TIR imagery was orthorectified and georeferenced. Three-dimensional maps of apparent surface temperature and radiant hydrothermal heat flux were then visualized and analyzed from various computer platforms (e.g., Google Earth, ArcGIS). We demonstrate this method at the Mammoth Mountain fumarole area on Mammoth Mountain, CA. Time-averaged apparent surface temperatures and radiant hydrothermal heat fluxes were observed up to 73.7 oC and 450 W m-2, respectively, while the estimated radiant hydrothermal heat emission rate from the area was 1.54 kW. Results should provide a basis for monitoring potential volcanic unrest and mitigating hydrothermal heat-related hazards on the volcano.

δ expansion applied to quantum electrodynamics

International Nuclear Information System (INIS)

Bender, C.M.; Boettcher, S.; Milton, K.A.

1992-01-01

A recently proposed technique known as the δ expansion provides a nonperturbative treatment of a quantum field theory. The δ-expansion approach can be applied to electrodynamics in such a way that local gauge invariance is preserved. In this paper it is shown that for electrodynamic processes involving only external photon lines and no external electron lines the δ expansion is equivalent to a fermion loop expansion. That is, the coefficient of δ n in the δ expansion is precisely the sum of all n-electron-loop Feynman diagrams in a conventional weak-coupling approximation. This equivalence does not extend to processes having external electron lines. When external electron lines are present, the δ expansion is truly nonperturbative and does not have a simple interpretation as a resummation of conventional Feynman diagrams. To illustrate the nonperturbative character of the δ expansion we perform a speculative calculation of the fermion condensate in the massive Schwinger model in the limit of large coupling constant

75 FR 11511 - Rogue River-Siskiyou National Forest; Mt. Ashland Ski Area Expansion, Jackson County, OR

Science.gov (United States)

2010-03-11

... Court of Appeals found it necessary to understand the type of habitat the Pacific fisher requires for... Appeals for the Ninth Circuit in CV-05-03004-PA, to conditionally authorize expansion of the Mt. Ashland... Alternative 6. The Forest Service received twenty-eight notices of appeal to the ROD. In December 2004, the...

High temperature expansions for the free energy of vortices respectively the string tension in lattice gauge theories

International Nuclear Information System (INIS)

Muenster, G.

1980-05-01

We derive high temperature cluster expansions for the free energy of vortices in SU(2) and Z 2 lattice gauge theories in 3 and 4 dimensions. The expected behaviour of the vortex free energy is verified. It obeys an area law behaviour. The coefficient of the area is shown to be equal to the string tension between static quarks. We calculate its expansion up to 12th order. For SU(2) in 4 dimensions the result is compared with Monte Carlo calculations of Creutz and is in good agreement at strong and intermediate coupling. (orig.)

The Role of Public and Private Insurance Expansions and Premiums for Low-income Parents: Lessons From State Experiences.

Science.gov (United States)

Guy, Gery P; M Johnston, Emily; Ketsche, Patricia; Joski, Peter; Adams, E Kathleen

2017-03-01

Numerous states have implemented policies expanding public insurance eligibility or subsidizing private insurance for parents. To assess the impact of parental health insurance expansions from 1999 to 2012 on the likelihood that parents are insured; their children are insured; both the parent and child within a family unit are insured; and the type of insurance. Cross-sectional analysis of the 2000-2013 March supplements to the Current Population Survey, with data from the Medical Expenditure Panel Survey-Insurance Component and the Area Resource File. Cross-state and within-state multivariable regression models estimated the effects of health insurance expansions targeting parents using 2-way fixed effect modeling and difference-in-difference modeling. All analyses controlled for household, parent, child, and local area characteristics that could affect insurance status. Expansions increased parental coverage by 2.5 percentage points, and increased the likelihood of both parent and child being insured by 2.1 percentage points. Substantial variation was observed by type of expansion. Public expansions without premiums and special subsidized plan expansions had the largest effects on parental coverage and increased the likelihood of jointly insuring both the parent and child. Higher premiums were a substantial deterrent to parents' insurance. Our findings suggest that premiums and the type of insurance expansion can have a substantial impact on the insurance status of the family. These findings can help inform states as they continue to make decisions about expanding Medicaid under the Affordable Care Act to cover all family members.

X-RAY FADING AND EXPANSION IN THE “MINIATURE SUPERNOVA REMNANT” OF GK PERSEI

Energy Technology Data Exchange (ETDEWEB)

Takei, D. [Institute of Physical and Chemical Research (RIKEN), RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Drake, J. J.; Slane, P. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Yamaguchi, H. [NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Uchiyama, Y. [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); Katsuda, S., E-mail: takei@spring8.or.jp [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

2015-03-10

We report on a second epoch of Chandra X-ray imaging spectroscopy of the spatially resolved old nova remnant GK Persei. An ACIS-S3 observation of 97.4 ks was conducted in 2013 November after a lapse of 13.8 yr from the last visit in 2000. The X-ray emitting nebula appeared more faint and patchy compared with the first epoch. The flux decline was particularly evident in fainter regions and the mean decline was 30%–40% in the 0.5–1.2 keV energy band. A typical expansion of the brightest part of the remnant was 1.″9, which corresponds to an expansion rate of 0.″14 yr{sup −1}. The soft X-ray spectra extracted from both the 2000 and 2013 data can be explained by a non-equilibrium ionization collisional plasma model convolved with interstellar absorption, though do not allow us to constrain the origin of the flux evolution. The plasma temperature has not significantly evolved since the 2000 epoch and we conclude that the fading of the X-ray emission is due largely to expansion. This implies that recent expansion has been into a lower density medium, a scenario that is qualitatively consistent with the structure of the circumstellar environment photographed soon after the initial explosion more than a century ago. Fainter areas are fading more quickly than brighter areas, indicating that they are fainter because of a lower ambient medium density and consequently more rapid expansion.

An incentive mechanism for electricity transmission expansion in Mexico

Energy Technology Data Exchange (ETDEWEB)

Rosellon, Juan [Division de Economia, Centro de Investigacion y Docencia Economicas (CIDE), Carret. Mexico-Toluca 3655, Lomas de Santa Fe, C.P. 01210, Mexico DF (Mexico)

2007-05-15

This study proposes an incentive regulatory framework for expanding electricity transmission in Mexico. A two-part pricing model is implemented within a combined merchant-regulatory structure. Three cases are considered. In the first, a monopolist with ''postage stamp tariffs'' serves the whole country using uniform prices. In the second case, one firm holds a regional monopoly in each of the five electricity areas. In the third, a monopolist operates in all areas of the national electricity system and discriminates in the prices it charges in each of the regions. This approach is described and then applied to the Mexican electricity transmission network. Using real data, the study compares all three cases in terms of profits, capacity increases, and network expansion. The results are found to depend on two effects: the ''economies-of-scale effect'', in which the maximum level is reached with a single network; and the ''discriminatory effect'' that results when a firm can discriminate among types of consumers. The economies-of-scale effect produces greater capacity and network expansion, whereas the discriminatory effect increases profits. (author)

Accelerating the loop expansion

International Nuclear Information System (INIS)

Ingermanson, R.

1986-01-01

This thesis introduces a new non-perturbative technique into quantum field theory. To illustrate the method, I analyze the much-studied phi 4 theory in two dimensions. As a prelude, I first show that the Hartree approximation is easy to obtain from the calculation of the one-loop effective potential by a simple modification of the propagator that does not affect the perturbative renormalization procedure. A further modification then susggests itself, which has the same nice property, and which automatically yields a convex effective potential. I then show that both of these modifications extend naturally to higher orders in the derivative expansion of the effective action and to higher orders in the loop-expansion. The net effect is to re-sum the perturbation series for the effective action as a systematic ''accelerated'' non-perturbative expansion. Each term in the accelerated expansion corresponds to an infinite number of terms in the original series. Each term can be computed explicitly, albeit numerically. Many numerical graphs of the various approximations to the first two terms in the derivative expansion are given. I discuss the reliability of the results and the problem of spontaneous symmetry-breaking, as well as some potential applications to more interesting field theories. 40 refs

Thermal expansion data

International Nuclear Information System (INIS)

Taylor, D.

1984-01-01

This paper gives regression data for a modified second order polynomial fitted to the expansion data of, and percentage expansions for dioxides with (a) the fluorite and antifluorite structure: AmO 2 , BkO 2 , CeO 2 , CmO 2 , HfO 2 , Li 2 O, NpO 2 , PrO 2 , PuO 2 , ThO 2 , UO 2 , ZrO 2 , and (b) the rutile structure: CrO 2 , GeO 2 , IrO 2 , MnO 2 , NbO 2 , PbO 2 , SiO 2 , SnO 2 , TeO 2 , TiO 2 and VO 2 . Reduced expansion curves for the dioxides showed only partial grouping into iso-electronic series for the fluorite structures and showed that the 'law of corresponding states' did not apply to the rutile structures. (author)

Alterations of apparent diffusion coefficient (ADC) in the brain of rats chronically exposed to lead acetate.

Science.gov (United States)

López-Larrubia, Pilar; Cauli, Omar

2011-03-15

Diffusion-weighted imaging (DWI) allows the assessment of the water apparent diffusion coefficient (ADC), a measure of tissue water diffusivity which is altered during different pathological conditions such as cerebral oedema. By means of DWI, we repeatedly measured in the same rats apparent diffusion coefficient ADC in different brain areas (motor cortex (MCx), somato-sensory cortex (SCx), caudate-putamen (CPu), hippocampus (Hip), mesencephalic reticular formation (RF), corpus callosum (CC) and cerebellum (Cb)) after 1 week, 4 and 12 weeks of lead acetate exposure via drinking water (50 or 500 ppm). After 12 weeks of lead exposure rats received albumin-Evans blue complex administration and were sacrificed 1h later. Blood-brain barrier permeability and water tissue content were determined in order to evaluate their relationship with ADC changes. Chronic exposure to lead acetate (500 ppm) for 4 weeks increased ADC values in Hip, RF and Cb but no in other brain areas. After 12 weeks of lead acetate exposure at 500 ppm ADC is significantly increased also in CPu and CC. Brain areas displaying high ADC values after lead exposure showed also an increased water content and increased BBB permeability to Evans blue-albumin complex. Exposure to 50 ppm for 12 weeks increased ADC values and BBB permeability in the RF and Cb. In summary, chronic lead exposure induces cerebral oedema in the adult brain depending on the brain area and the dose of exposure. RF and Cb appeared the most sensitive brain areas whereas cerebral cortex appears resistant to lead-induced cerebral oedema. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Thermal expansion of beryllium oxide

International Nuclear Information System (INIS)

Solodukhin, A.V.; Kruzhalov, A.V.; Mazurenko, V.G.; Maslov, V.A.; Medvedev, V.A.; Polupanova, T.I.

1987-01-01

Precise measurements of temperature dependence of the coefficient of linear expansion in the 22-320 K temperature range on beryllium oxide monocrystals are conducted. A model of thermal expansion is suggested; the range of temperature dependence minimum of the coefficient of thermal expansion is well described within the frames of this model. The results of the experiment may be used for investigation of thermal stresses in crystals

Convergence of mayer expansions

International Nuclear Information System (INIS)

Brydges, D.C.

1986-01-01

The tree graph bound of Battle and Federbush is extended and used to provide a simple criterion for the convergence of (iterated) Mayer expansions. As an application estimates on the radius of convergence of the Mayer expansion for the two-dimensional Yukawa gas (nonstable interaction) are obtained

Observations of apparent superslow wave propagation in solar prominences

Science.gov (United States)

Raes, J. O.; Van Doorsselaere, T.; Baes, M.; Wright, A. N.

2017-06-01

Context. Phase mixing of standing continuum Alfvén waves and/or continuum slow waves in atmospheric magnetic structures such as coronal arcades can create the apparent effect of a wave propagating across the magnetic field. Aims: We observe a prominence with SDO/AIA on 2015 March 15 and find the presence of oscillatory motion. We aim to demonstrate that interpreting this motion as a magneto hydrodynamic (MHD) wave is faulty. We also connect the decrease of the apparent velocity over time with the phase mixing process, which depends on the curvature of the magnetic field lines. Methods: By measuring the displacement of the prominence at different heights to calculate the apparent velocity, we show that the propagation slows down over time, in accordance with the theoretical work of Kaneko et al. We also show that this propagation speed drops below what is to be expected for even slow MHD waves for those circumstances. We use a modified Kippenhahn-Schlüter prominence model to calculate the curvature of the magnetic field and fit our observations accordingly. Results: Measuring three of the apparent waves, we get apparent velocities of 14, 8, and 4 km s-1. Fitting a simple model for the magnetic field configuration, we obtain that the filament is located 103 Mm below the magnetic centre. We also obtain that the scale of the magnetic field strength in the vertical direction plays no role in the concept of apparent superslow waves and that the moment of excitation of the waves happened roughly one oscillation period before the end of the eruption that excited the oscillation. Conclusions: Some of the observed phase velocities are lower than expected for slow modes for the circumstances, showing that they rather fit with the concept of apparent superslow propagation. A fit with our magnetic field model allows for inferring the magnetic geometry of the prominence. The movie attached to Fig. 1 is available at http://www.aanda.org

Fertility and apparent genetic anticipation in Lynch syndrome.

Science.gov (United States)

Stupart, Douglas; Win, Aung Ko; Jenkins, Mark; Winship, Ingrid M; Goldberg, Paul; Ramesar, Rajkumar

2014-09-01

Genetic anticipation is the phenomenon in which age of onset of an inherited disorder decreases in successive generations. Inconsistent evidence suggests that this occurs in Lynch syndrome. A possible cause for apparent anticipation is fecundity bias, which occurs if the disease adversely affects fertility. The purpose of this study was to determine the effect of age of diagnosis of colorectal cancer (CRC) on lifetime fertility in Lynch syndrome, and whether this can falsely create the appearance of genetic anticipation. A computer model simulated age of diagnosis of CRC in hypothetical Lynch syndrome carriers and their offspring. The model assumed similar age distribution of CRC across generations (i.e. that there was no true anticipation). Age distribution of CRC diagnosis, and lifetime fertility rates (grouped by age of diagnosis of CRC) were determined from the Australasian Colorectal Cancer Family Registry (ACCFR). Apparent anticipation was calculated by comparing ages of diagnosis of CRC in affected parent-child pairs. A total of 1,088 patients with CRC were identified from the ACCFR. Total lifetime (cohort) fertility was related to age of diagnosis of CRC (correlation coefficient 0.13, P = 0.0001). In the simulation, apparent anticipation was 1.8 ± 0.54 years (P = 0.0044). Observed apparent anticipation in the ACCFR cohort was 4.8 ± 1.73 years (P = 0.0064). There was no difference in apparent anticipation between the simulate d and observed parent-child pairs (P = 0.89). The appearance of genetic anticipation in Lynch syndrome can be falsely created due to changes in fertility.

Overview of the environmental impact assessment for the proposed expansion of the Elliot Lake Ontario uranium mines

International Nuclear Information System (INIS)

Gorber, D.M.; Graham, R.G.; Ibbotson, B.G.

1978-01-01

As a result of the resurgence in the demand for uranium, Denison Mines Limited and Rio Algom Limited began preparations, in 1973 and 1974 respectively, for expansion of their facilities at Elliot Lake, Ontario. These programmes involved not only the expansion of facilities currently in operation in the area, but also the rehabilitation of non-operating properties that were previously used during the 1960's. This paper reviews the methodology employed during the environmental assessment study of the proposed expansion and highlights the long and short-term strategies recommended

Shape reconstruction from apparent contours theory and algorithms

CERN Document Server

Bellettini, Giovanni; Paolini, Maurizio

2015-01-01

Motivated by a variational model concerning the depth of the objects in a picture and the problem of hidden and illusory contours, this book investigates one of the central problems of computer vision: the topological and algorithmic reconstruction of a smooth three dimensional scene starting from the visible part of an apparent contour. The authors focus their attention on the manipulation of apparent contours using a finite set of elementary moves, which correspond to diffeomorphic deformations of three dimensional scenes. A large part of the book is devoted to the algorithmic part, with implementations, experiments, and computed examples. The book is intended also as a user's guide to the software code appcontour, written for the manipulation of apparent contours and their invariants. This book is addressed to theoretical and applied scientists working in the field of mathematical models of image segmentation.

Spatial Pattern and the Process of Settlement Expansion in Jiangsu Province from 1980 to 2010, Eastern China

Directory of Open Access Journals (Sweden)

Yan Xu

2014-11-01

Full Text Available Human settlement expansion has very important effects on regional population migration, economic balance and ecosystem services. Understanding the evolution of settlement expansion and regional differences is significant for regional sustainability. The results showed that in the past 30 years, the urbanization rate in Jiangsu province was lower. From 1980 to 2010, the expansion area of urban settlement was larger than that of rural settlement. Urban settlement expanded slowly from 1980 to 2005 and strongly from 2005 to 2010. Rural settlement expanded greatly from 1980 to 1995, and 37.14% of settlement was mostly on cropland. The type of urban settlement expansion from 1980 to 1995 and from 2000 to 2005 was compact expansion. Settlement expansion in the south of Jiangsu province was greater than that in the north of Jiangsu province. The spatial pattern of settlement in most cities was a cluster. In the past 30 years, urban and rural settlement expansion had significantly different impacts on the soil and water environment. Urban settlement expansion was great in the south of Jiangsu province and widened the economic and social gap between the south and north of Jiangsu province.

Modeling apparent color for visual evaluation of camouflage fabrics

Science.gov (United States)

Ramsey, S.; Mayo, T.; Shabaev, A.; Lambrakos, S. G.

2017-08-01

As the U.S. Navy, Army, and Special Operations Forces progress towards fielding more advanced uniforms with multi-colored and highly detailed camouflage patterning, additional test methodologies are necessary in evaluating color in these types of camouflage textiles. The apparent color is the combination of all visible wavelengths (380-760 nm) of light reflected from large (>=1m2 ) fabric sample sizes for a given standoff distance (10-25ft). Camouflage patterns lose resolution with increasing standoff distance, and eventually all colors within the pattern appear monotone (the "apparent color" of the pattern). This paper presents an apparent color prediction model that can be used for evaluation of camouflage fabrics.

Is China ready for its nuclear expansion?

International Nuclear Information System (INIS)

Zhou, Yun; Rengifo, Christhian; Hinze, Jonathan; Chen, Peipei

2011-01-01

China's rapid pace of nuclear energy growth is unique, and its impact on the global nuclear market as both a customer and potential future supplier is already tremendous and will continue to expand. It is crucial to understand this energy policy development and its impact on various global areas. Unfortunately, there is relatively limited English-language information available about China's nuclear power industry and its current development. This paper aims to provide a comprehensive assessment of the Chinese nuclear energy program and policy, reviewing its past, present, likely future developments, as well as to consider potential challenges that deserve further attention. This paper will explore reasons that have caused the existing industry, describe China's nuclear bureaucracy and decision making process to understand how different stakeholders play a role in China's nuclear energy development. This study concludes that China's existing nuclear program and industry, in combination with its current stable economic and political environment, provides a sound foundation for the planned nuclear expansion. However, challenges which are crucial to the success of the nuclear expansion will need to be addressed. (author)

Simulation and Experimental Study of Arc Column Expansion After Ignition in Low-Voltage Circuit Breakers

Institute of Scientific and Technical Information of China (English)

MA Qiang; RONG Mingzhe; WU Yi; XU Tiejun; SUN Zhiqiang

2008-01-01

The dynamicprocess of arc pressure and corresponding arc column expansion, which is the main feature after arc ignition and has a significant effect on the breaking behaviour of low -voltage circuit breakers, is studied. By constructing a three dimensional mathematical model of air arc plasma and adopting the Control Volume Method, the parameters of arc plasma including temperature and pressure axe obtained. The variations of pressure field and temperature field with time are simulated. The result indicates that there are six stages for the process of arc column expansion according to the variation of pressure in arc chamber. In the first stage, the maximal pressure locates in the region close to cathode, and in the second stage the maximal pressure shifts to the region close to the anode. In the third stage, the pressure difference between the middle of arc column and the ambient gas is very large, so the arc column begins to expand apparently. In the fourth stage, the pressure wave propagates towards both ends and the maximal pressure appears at the two ends when the pressure wave reaches both sidewalls. In the fifth stage, the pressure wave is reflected and collides in the middle of the arc chamber. In the last stage, the propagation and reflection of pressure wave will repeat several times until a steady burning state is reached. In addition, the experimental results of arc column expansion, corresponding to the arc pressure variation, are presented to verify the simulation results.

Pushing the Limits: The Pattern and Dynamics of Rubber Monoculture Expansion in Xishuangbanna, SW China.

Directory of Open Access Journals (Sweden)

Huafang Chen

Full Text Available The rapidly growing car industry in China has led to an equally rapid expansion of monoculture rubber in many regions of South East Asia. Xishuangbanna, the second largest rubber planting area in China, located in the Indo-Burma biodiversity hotspot, supplies about 37% of the domestic natural rubber production. There, high income possibilities from rubber drive a dramatic expansion of monoculture plantations which poses a threat to natural forests. For the first time we mapped rubber plantations in and outside protected areas and their net present value for the years 1988, 2002 (Landsat, 30 m resolution and 2010 (RapidEye, 5 m resolution. The purpose of our study was to better understand the pattern and dynamics of the expansion of rubber plantations in Xishuangbanna, as well as its economic prospects and conservation impacts. We found that 1 the area of rubber plantations was 4.5% of the total area of Xishuangbanna in 1988, 9.9% in 2002, and 22.2% in 2010; 2 rubber monoculture expanded to higher elevations and onto steeper slopes between 1988 and 2010; 3 the proportion of rubber plantations with medium economic potential dropped from 57% between 1988 and 2002 to 47% in 2010, while the proportion of plantations with lower economic potential had increased from 30% to 40%; and 4 nearly 10% of the total area of nature reserves within Xishuangbanna has been converted to rubber monoculture by 2010. On the basis of our findings, we conclude that the rapid expansion of rubber plantations into higher elevations, steeper terrain, and into nature reserves (where most of the remaining forests of Xishuangbanna are located poses a serious threat to biodiversity and environmental services while not producing the expected economic returns. Therefore, it is essential that local governments develop long-term land use strategies for balancing economic benefits with environmental sustainability, as well as for assisting farmers with the selection of land suitable

Climate change drives expansion of Antarctic ice-free habitat

Science.gov (United States)

Lee, Jasmine R.; Raymond, Ben; Bracegirdle, Thomas J.; Chadès, Iadine; Fuller, Richard A.; Shaw, Justine D.; Terauds, Aleks

2017-07-01

Antarctic terrestrial biodiversity occurs almost exclusively in ice-free areas that cover less than 1% of the continent. Climate change will alter the extent and configuration of ice-free areas, yet the distribution and severity of these effects remain unclear. Here we quantify the impact of twenty-first century climate change on ice-free areas under two Intergovernmental Panel on Climate Change (IPCC) climate forcing scenarios using temperature-index melt modelling. Under the strongest forcing scenario, ice-free areas could expand by over 17,000 km2 by the end of the century, close to a 25% increase. Most of this expansion will occur in the Antarctic Peninsula, where a threefold increase in ice-free area could drastically change the availability and connectivity of biodiversity habitat. Isolated ice-free areas will coalesce, and while the effects on biodiversity are uncertain, we hypothesize that they could eventually lead to increasing regional-scale biotic homogenization, the extinction of less-competitive species and the spread of invasive species.

Prevalence of dyslipidaemia amongst apparently healthy staff of a ...

African Journals Online (AJOL)

The aim of this study is to determine the serum lipid profile of apparently healthy staff of University of Benin Teaching Hospital (UBTH), Benin City. Consenting staff of UBTH who were apparently healthy were recruited for the study. Data extracted included the patient's age, sex, body mass index, weight, height, waist ...

$\\delta$-Expansion at Finite Temperature

OpenAIRE

Ramos, Rudnei O.

1996-01-01

We apply the $\\delta$-expansion perturbation scheme to the $\\lambda \\phi^{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $\\delta$-expansion the interaction term is written as $\\lambda (\\phi^{2})^{ 1 + \\delta}$ and $\\delta$ is considered as the perturbation parameter. We compute within this perturbative approach the renormalized mass at finite temperature at a finite order in $\\delta$. The results are compared with the usual loop-expansion at finite temperature.

Electrical Resistance Alloys and Low-Expansion Alloys

DEFF Research Database (Denmark)

Kjer, Torben

1996-01-01

The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...... thermoelastic coefficients and age hardenable low expansion alloys....

Disjoint sum expansion method in FTA

International Nuclear Information System (INIS)

Ruan Keqiang

1987-01-01

An expansion formula for transforming boolean algebraic expressions into disjoint form was proved. Based on this expansion formula, a method for transforming system failure function into disjoint form was devised. The fact that the expansion can be done for several elements simulatneously makes the method flexible and fast. Some examples from fault tree analysis (FTA) and network analysis were examined by the new method to show its algorithm and its merit. Besides, by means of the proved expansion formula some boolean algebraic relations can proved very easily

Maxwell superalgebras and Abelian semigroup expansion

Directory of Open Access Journals (Sweden)

P.K. Concha

2014-09-01

Full Text Available The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2 leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM(N recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N. Moreover, we show that new minimal Maxwell superalgebras type sMm+2 and their N-extended generalization can be obtained using the S-expansion procedure.

Maxwell superalgebras and Abelian semigroup expansion

Energy Technology Data Exchange (ETDEWEB)

Concha, P.K.; Rodríguez, E.K. [Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Dipartimento di Scienza Applicata e Tecnologia (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Torino, Via Pietro Giuria, 1, 10125 Torino (Italy)

2014-09-15

The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2) leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM{sup (N)} recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N). Moreover, we show that new minimal Maxwell superalgebras type sM{sub m+2} and their N-extended generalization can be obtained using the S-expansion procedure.

Inhibition of apparent photosynthesis by nitrogen oxides

Energy Technology Data Exchange (ETDEWEB)

Hill, A C; Bennett, J H

1970-01-01

The nitrogen oxides (NO/sub 2/ and NO) inhibited apparent photosynthesis of oats and alfalfa at concentrations below those required to cause visible injury. There appeared to be a threshold concentration of about 0.6 ppm for each pollutant. An additive effect in depressing apparent photosynthesis occurred when the plants were exposed to a mixture of NO and NO/sub 2/. Although NO produced a more rapid effect on the plants, lower concentrations of NO/sub 2/ were required to cause a given inhibition after 2 hour of exposure. Inhibition by nitric oxide was more closely related to its partial pressure than was inhibition by NO/sub 2/.

The effects of boreal forest expansion on the summer Arctic frontal zone

Energy Technology Data Exchange (ETDEWEB)

Liess, Stefan; Snyder, Peter K.; Harding, Keith J. [University of Minnesota, Department of Soil, Water, and Climate, Saint Paul, MN (United States)

2012-05-15

Over the last 100 years, Arctic warming has resulted in a longer growing season in boreal and tundra ecosystems. This has contributed to a slow northward expansion of the boreal forest and a decrease in the surface albedo. Corresponding changes to the surface and atmospheric energy budgets have contributed to a broad region of warming over areas of boreal forest expansion. In addition, mesoscale and synoptic scale patterns have changed as a result of the excess energy at and near the surface. Previous studies have identified a relationship between the positioning of the boreal forest-tundra ecotone and the Arctic frontal zone in summer. This study examines the climate response to hypothetical boreal forest expansion and its influence on the summer Arctic frontal zone. Using the Weather Research and Forecasting model over the Northern Hemisphere, an experiment was performed to evaluate the atmospheric response to expansion of evergreen and deciduous boreal needleleaf forests into open shrubland along the northern boundary of the existing forest. Results show that the lower surface albedo with forest expansion leads to a local increase in net radiation and an average hemispheric warming of 0.6 C at and near the surface during June with some locations warming by 1-2 C. This warming contributes to changes in the meridional temperature gradient that enhances the Arctic frontal zone and strengthens the summertime jet. This experiment suggests that continued Northern Hemisphere high-latitude warming and boreal forest expansion might contribute to additional climate changes during the summer. (orig.)

Uniform gradient expansions

CERN Document Server

Giovannini, Massimo

2015-01-01

Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

The inertial properties of pulsing interflow area of counterflow hydrodynamic radiator

Directory of Open Access Journals (Sweden)

Тetyana V. Makarova

2015-12-01

Full Text Available The jet hydrodynamic radiators (HDR are the devices where part of kinetic energy of flooded jet is transformed to pulsations of internal interflow area and flow shell fluctuations. The sound generation process in HDR is involved with its constructional features. Aim: The aim of this work is to study the inertial properties of the HDR pulsating interflow area taking into account its geometric singularities. Materials and Methods: It was proposed to study the pulsating area using the simplified sphere model of pulsating cavitating area of the counterflow type jet hydrodynamic radiator. This radiator can be implemented in two modifications: taking into account the volume that occupies by jet from the nozzle with and without accounting of it. Results: The characteristic dimensions and spatial restrictions are determined for the mentioned modifications based on the research results. The own mass, apparent mass and total mass of pulsating area (pulsator were determined. The dependencies of the corresponding mass relations versus pulsator radius were obtained. Conclusions: It was shown that specifically apparent mass has dominance in total one and it is almost 6 times greater than pulsator own mass. The consideration of the central axial passage occupied by jet out of muzzle increases the contribution of apparent mass to total mass. The influence of apparent mass intensifies under increase of the gas content of dual-phase environment, i.e. under cavitation propagation. The total masses of pulsating area are nearest one to another in various models modifications due to cancellation effect of two factors - increase of pulsator apparent mass and decrease of its own mass under comparatively low sphere volume.

The rate of thermal expansion of a thin metallic slab of arbitrary shape.

Science.gov (United States)

Lee, Y C

2009-08-12

In a previous paper the rate of thermal expansion of a long, slender insulating bar has been worked out. Our present aim is to extend that work to the thermal expansion rate of not only a long metallic bar, but to further generalize it to a thin metallic slab of arbitrary shape. Assuming that the thickness of the slab is small compared to the linear dimension of its area we again take advantage of the two distinct, disparate timescales to turn the familiar problem of thermal expansion into a time-dependent problem of the rate of the expansion. Based on the previously established finite physical momentum of an acoustic phonon when translational invariance is broken, we show that the combined pressure of the phonons and the free electrons due to their outward momenta would suffer a Doppler reduction as the specimen expands upon heating. This Doppler reduction gives rise to damping of the expanding motion, thus yielding as a first result the time of thermal expansion of a long slender metal bar. The generalization to the important case of a thin metallic slab of any shape is then worked out in detail before a concluding section containing a long physical discussion and summary.

Ultraintense laser interaction with nanoscale targets: a simple model for layer expansion and ion acceleration

International Nuclear Information System (INIS)

Albright, B J; Yin, L; Hegelich, B M; Bowers, K J; Huang, C; Fernandez, J C; Flippo, K A; Gaillard, S A; Kwan, T J T; Henig, A; Tajima, T; Habs, D; Yan, X Q

2010-01-01

A simple model has been derived for expansion of a thin (up to 100s of nm thickness) target initially of solid density irradiated by an ultraintense laser. In this regime, ion acceleration mechanisms, such as the Break-Out Afterburner (BOA) [1], emerge with the potential for dramatically improved energy, efficiency, and energy spread. Ion beams have been proposed [2] as drivers for fast ignition inertial confinement fusion [3]. Analysis of kinetic simulations of the BOA shows the period of enhanced acceleration occurs between times t 1 , when the target becomes relativistically transparent to the laser, and t 2 , when the target becomes classically underdense and the enhanced acceleration terminates. A simple model for target expansion has been derived that contains early, one-dimensional (1D) expansion of the target and three-dimensional (3D) expansion at late times. The model assumes expansion is slab-like at the instantaneous ion sound speed and requires as input target composition, laser intensity, laser spot area, and the efficiency of laser absorption into electron thermal energy.

Key Biodiversity Areas in the Indo-Burma Hotspot: Process, Progress and Future Directions

Directory of Open Access Journals (Sweden)

A.W. Tordoff

2012-08-01

Full Text Available Key Biodiversity Areas (KBAs provide geographic targets for the expansion of protected area coverage, and identify sites for urgent conservation action. Identification of KBAs in the Indo-Burma Hotspot was undertaken during 2003, for a region of analysis comprising Cambodia, Lao PDR, Myanmar (Burma, Thailand and Vietnam, plus parts of southern China. The starting point was information on 282 Important Bird Areas identified by BirdLife International and collaborators. These data were then overlaid with point locality data on globally threatened mammals, reptiles, amphibians, freshwater fish and plants, with additional KBAs identified as required. Through this process, a total of 438 KBAs were identified, covering 258,085km2 or 11.5 percent of the region of analysis. Only 58 percent of the KBAs are wholly or partly included within protected areas, suggesting that there may be a need for further expansion of protected area networks, particularly in Myanmar and Vietnam. The criteria for KBA identification are triggered by 812 species, of which 23 are believed only to occur at a single KBA globally. The KBAs have proven to be a useful conservation priority setting tool in Indo-Burma, helping to guide investments by various donors and application of environmental safeguard policies by international financial institutions. There are fewer examples of KBAs being used to guide expansion of protected area systems in Indo-Burma. In large part, this is because the period of rapid expansion of protected areas in most hotspot countries predated the KBA identification process, and political support for further significant expansion is currently limited.

Thin foil expansion into a vacuum

International Nuclear Information System (INIS)

Mora, P.

2005-01-01

Plasma expansion into a vacuum is an old problem which has been renewed recently in various contexts: expansion of ultra-cold plasmas, cluster expansion, of dust grains, expansion of thin foils. In this presentation I will first discuss the physics of the expansion of a thin foil irradiated by an ultra-short ultra-intense laser pulse. The expansion results in the formation of high energy ions. For an infinitely steep plasma-vacuum interface the fastest ions are located in the outer part of the expansion and their velocity is given by ν m ax∼ 2 C s (In ω p it) where c s (Zk B T e /m i )''1/2 is the ion-acoustic velocity ω p i=(n e 0Ze''2/m i e 0 )''1/2 is the ion plasma frequency, n e 0 is the electron density in the unperturbed plasma, Z is the ion charge number. In the above expression, t is either the pulse duration or the effective acceleration time (in particular t∼L/2c s , where L is the width of the foil, when the electron cooling is taken into account). A salient characteristic of the expansion is the occurrence of a double layer structure and a peak of the accelerating electric field at the ion front. I will explain the origin of the peak and predict its temporal behavior. This peak has been diagnosed in recent experiments. I will also discuss the effect of a 2-temperatures electron distribution function on the expansion, showing the dominant role of the hot electron component. Finally I will discuss the occurrence of ion spikes in the expansion when the initial density profile is smooth. The ion spike is due to a wave breaking which cannot be handled in a satisfactory way by a fluid code and requires a kinetic description. A. simple collisionless particle code has been used to treat the evolution of the spike after the wave breaking and the results will be shown. (Author)

Hawking radiation of an apparent horizon in a FRW universe

International Nuclear Information System (INIS)

Cai Ronggen; Cao Liming; Hu Yapeng

2009-01-01

Hawking radiation is an important quantum phenomenon of a black hole, which is closely related to the existence of an event horizon of a black hole. The cosmological event horizon of de Sitter space is also of Hawking radiation with a thermal spectrum. By use of the tunneling approach, we show that there is indeed a Hawking radiation with temperature, T=1/(2πr-tilde A , for a locally defined apparent horizon of a Friedmann-Robertson-Walker universe with any spatial curvature, where r-tilde A is the apparent horizon radius. Thus we fill in the gap existing in the literature investigating the relation between the first law of thermodynamics and Friedmann equations; there the apparent horizon is assumed to have such a temperature without any proof. In addition, we stress the implication of the Hawking temperature associated with the apparent horizon.

Series solutions to partial differential equations. A study of the singularities, expansions, and solutions of Schroedinger's equation for the helium atom

International Nuclear Information System (INIS)

Mahlab, M.S.

1975-01-01

All the presently available techniques for solving Schroedinger's differential equation for helium-like atoms display poor convergence of the wave function in the neighborhood of the singularities of the Hamiltonian operator. In general most of the methods of solving this equation will converge in the appropriate limit to the exact wave function; however, convergence is slow, especially near the singularities of this differential equation. These difficulties become readily apparent from local energy studies. A technique is presented that avoids these difficulties. The wave function it produces is specifically most accurate at the singularities of the Hamiltonian. The novel aspect of this treatment is the subdivision of the space spanned by the wave function. Different expansions are picked such that they converge rapidly in each of the different subdivisions. These expansions may be constructed in such a way that they obey the boundary conditions in their respective subdivision. Most importantly, all the information available from the recursion relations associated with the differential equation may be incorporated into these expansions. A systematic procedure is presented such that these expansions may be brought together to form a wave function that satisfies all the continuity requirements. An S-state helium wave function was constructed to demonstrate that this method of treatment is feasible, and capable of indefinite systematic improvement. A discussion of several new asymptotic expansions that were constructed for the helium wave function, as well as an improved functional form for the small electron-nucleus wave function, is included in this presentation

Shrub expansion in SW Greenland under modest regional warming

DEFF Research Database (Denmark)

Jørgensen, Rasmus Halfdan; Meilby, Henrik; Kollmann, Johannes

2013-01-01

Shrub expansion has been observed widely in tundra areas across the Arctic. This phenomenon has been partially attributed to increasing temperatures over the past century. However, relationships among shrub expansion, grazing, and human disturbance have been studied little. SW Greenland...... is a subarctic to low-arctic region with a long and complex land-use history and only modest temperature increases over the past 50 years (0.2 °C decade-1), but changes in shrub cover have not previously been studied in this region. We compiled historical photographs of vegetation in SW Greenland (1898......–1974) and repeated the photos in 2010 and 2011. Sixty-four photo pairs were cropped into 133 smaller units and classified by aspect, substrate stability, muskoxen grazing, and human disturbance. The photo material was evaluated by 22 experts with respect to changes in shrub cover, revealing a general increase across...

Expansive soil stabilization with coir waste and lime for flexible pavement subgrade

Science.gov (United States)

Narendra Goud, G.; Hyma, A.; Shiva Chandra, V.; Sandhya Rani, R.

2018-03-01

Expansive soil properties can be improved by various methods to make it suitable for construction of flexible pavement. The coir pith is the by-product (bio-waste) generated from coir industry during extraction of coir fiber from coconut husk. Openly disposed coir pith can make the surrounding areas unhygienic. This bio-waste can be one of the potential materials to stabilize the expansive soils. In the present study coir pith and lime are used as stabilizers. Different combinations of coir pith contents (1%, 2% and 3%) and lime contents (2%, 3% and 4%)are used to study the behavior of expansive soil. Unconfined compressive strength (UCS) of unstabilized and stabilized soils was determined. Optimum content of coir pith and lime are determined based on UCS of the soil. California bearing ratio of soil determined at optimum contents of coir pith and lime. Flexible pavement layer compositions for two levels of traffic using stabilized soil subgrade.

Temperature-monitored optical treatment for radial tissue expansion.

Science.gov (United States)

Bak, Jinoh; Kang, Hyun Wook

2017-07-01

Esophageal stricture occurs in 7-23% of patients with gastroesophageal reflux disease. However, the current treatments including stent therapy, balloon dilation, and bougienage involve limitations such as stent migration, formation of the new strictures, and snowplow effect. The purpose of the current study was to investigate the feasibility of structural expansion in tubular tissue ex vivo during temperature-monitored photothermal treatment with a diffusing applicator for esophageal stricture. Porcine liver was used as an ex vivo tissue sample for the current study. A glass tube was used to maintain a constant distance between the diffuser and tissue surface and to evaluate any variations in the luminal area after 10-W 1470-nm laser irradiation for potential stricture treatment. The 3D goniometer measurements confirmed roughly isotropic distribution with less than 10% deviation from the average angular intensity over 2π (i.e., 0.86 ± 0.09 in arbitrary unit) from the diffusing applicator. The 30-s irradiation increased the tissue temperature up to 72.5 °C, but due to temperature feedback, the interstitial tissue temperature became saturated at 70 °C (i.e., steady-state error = ±0.4 °C). The irradiation times longer than 5 s presented area expansion index of 1.00 ± 0.04, signifying that irreversible tissue denaturation permanently deformed the lumen in a circular shape and secured the equivalent luminal area to that of the glass tube. Application of a temperature feedback controller for photothermal treatment with the diffusing applicator can regulate the degree of thermal denaturation to feasibly treat esophageal stricture in a tubular tissue.

Rapid maxillary expansion effects: An alternative assessment method by means of cone-beam tomography

Directory of Open Access Journals (Sweden)

Camilo Aquino Melgaço

2014-10-01

Full Text Available INTRODUCTION: This study aims to develop a method to assess the changes in palatal and lingual cross-sectional areas in patients submitted to rapid maxillary expansion (RME. METHODS: The sample comprised 31 Class I malocclusion individuals submitted to RME and divided into two groups treated with Haas (17 patients and Hyrax (14 patients expanders. Cone-beam computed tomography scans were acquired at T0 (before expansion and T1 (six months after screw stabilization. Maxillary and mandibular cross-sectional areas were assessed at first permanent molars and first premolars regions and compared at T0 and T1. Mandibular occlusal area was also analyzed. RESULTS: Maxillary cross-sectional areas increased in 56.18 mm2 and 44.32 mm2 for the posterior and anterior regions. These values were smaller for the mandible, representing augmentation of 40.32 mm2 and 39.91 mm2 for posterior and anterior sections. No differences were found when comparing both expanders. Mandibular occlusal area increased 43.99mm2 and mandibular incisors proclined. Increments of 1.74 mm and 1.7 mm occurred in mandibular intermolar and interpremolar distances. These same distances presented increments of 5.5 mm and 5.57 mm for the maxillary arch. CONCLUSION: Occlusal and cross-sectional areas increased significantly after RME. The method described seems to be reliable and precise to assess intraoral area changes.

Thermal expansion of L-ascorbic acid

Science.gov (United States)

Nicolaï, B.; Barrio, M.; Tamarit, J.-Ll.; Céolin, R.; Rietveld, I. B.

2017-04-01

The specific volume of vitamin C has been investigated by X-ray powder diffraction as a function of temperature from 110 K up to complete degradation around 440 K. Its thermal expansion is relatively small in comparison with other organic compounds with an expansivity α v of 1.2(3) × 10-4 K-1. The structure consists of strongly bound molecules in the ac plane through a dense network of hydrogen bonds. The thermal expansion is anisotropic. Along the b axis, the expansion has most leeway and is about 10 times larger than in the other directions.

Chemical graph-theoretic cluster expansions

International Nuclear Information System (INIS)

Klein, D.J.

1986-01-01

A general computationally amenable chemico-graph-theoretic cluster expansion method is suggested as a paradigm for incorporation of chemical structure concepts in a systematic manner. The cluster expansion approach is presented in a formalism general enough to cover a variety of empirical, semiempirical, and even ab initio applications. Formally such approaches for the utilization of chemical structure-related concepts may be viewed as discrete analogues of Taylor series expansions. The efficacy of the chemical structure concepts then is simply bound up in the rate of convergence of the cluster expansions. In many empirical applications, e.g., boiling points, chromatographic separation coefficients, and biological activities, this rate of convergence has been observed to be quite rapid. More note will be made here of quantum chemical applications. Relations to questions concerning size extensivity of energies and size consistency of wave functions are addressed

Defining chemical expansion: the choice of units for the stoichiometric expansion coefficient

DEFF Research Database (Denmark)

Marrocchelli, Dario; Chatzichristodoulou, Christodoulos; Bishop, Sean R.

2014-01-01

Chemical expansion refers to the spatial dilation of a material that occurs upon changes in its composition. When this dilation is caused by a gradual, iso-structural increase in the lattice parameter with composition, it is related to the composition change by the stoichiometric expansion coeffi...... are provided for changes in oxygen content in fluorite, perovskite, and Ruddlesden-Popper (K2NiF4) phase materials used in solid oxide fuel cells....

The Role of Governance in Agricultural Expansion and Intensification: a Global Study of Arable Agriculture

Directory of Open Access Journals (Sweden)

Menno Mandemaker

2011-06-01

Full Text Available In this research we studied empirical relationships between agricultural production dynamics and six quantitative World Bank governance indicators for 173 countries between 1975 and 2007. It is hypothesized that in countries with lower quality of governance, agricultural production increases are more likely to be achieved by area expansions than by increases in yields. We distinguished four groups of countries: those with both area and yield increases; those with increasing yields but decreasing area; those with decreasing yields but a growing area; and those with both declines in yields and area. We analyzed differences between these four groups, and also analyzed governance-production relationships within these groups. On average, quality of governance is low in countries with both area and yield increases and high in countries with increasing yields but decreasing area. Countries with declining yields were too few in number to allow for quantitative analyses. The analysis of governance-production relationships within the four groups suggests that countries with a lower quality of governance are more inclined to achieve production increases by expanding agricultural area rather than increasing yields. Additional explanatory value of governance indicators to agricultural production dynamics is generally small, but nevertheless significant in most cases. Our results suggest that, in order for agricultural production to increase without excessive expansions of agricultural area, governance issues should be resolved.

Edgeworth expansion for functionals of continuous diffusion processes

DEFF Research Database (Denmark)

Podolskij, Mark; Yoshida, Nakahiro

This paper presents new results on the Edgeworth expansion for high frequency functionals of continuous diffusion processes. We derive asymptotic expansions for weighted functionals of the Brownian motion and apply them to provide the Edgeworth expansion for power variation of diffusion processes....... Our methodology relies on martingale embedding, Malliavin calculus and stable central limit theorems for semimartingales. Finally, we demonstrate the density expansion for studentized statistics of power variations.......This paper presents new results on the Edgeworth expansion for high frequency functionals of continuous diffusion processes. We derive asymptotic expansions for weighted functionals of the Brownian motion and apply them to provide the Edgeworth expansion for power variation of diffusion processes...

Series expansion of two-dimensional fields produced by iron-core magnets

International Nuclear Information System (INIS)

Satoh, Kotaro.

1997-02-01

This paper discusses the validity of a series expansion of two-dimensional magnetic fields with harmonic functions, and suggests that the series may not converge outside of the pole gap. It also points out that this difficulty may appear due to a slow convergence of the series near to the pole edge, even within the convergent area. (author)

Expansion lyre-shaped tube

International Nuclear Information System (INIS)

Andro, Jean.

1973-01-01

The invention relates the expansion lyre-shaped tube portions formed in dudgeoned tubular bundles between two bottom plates. An expansion lyre comprises at least two sets of tubes of unequal lengths coplanar and symmetrical with respect to the main tube axis, with connecting portions between the tubes forming said sets. The invention applies to apparatus such as heat exchangers, heaters, superheaters or breeders [fr

Functional Apparent Moduli (FAMs) as Predictors of Oral Implant Osseointegration Dynamics

OpenAIRE

Chang, Po-Chun; Seol, Yang-Jo; Kikuchi, Noboru; Goldstein, Steven A.; Giannobile, William V.

2010-01-01

At present, limited functional data exists regarding the application and use of biomechanical and imaging technologies for oral implant osseointegration assessment. The objective of this investigation was to determine the functional apparent moduli (FAMs) that could predict the dynamics of oral implant osseointegration. Using an in vivo dental implant osseous healing model, two FAMs, functional bone apparent modulus (FBAM) and composite tissue apparent modulus (FCAM), of the selected peri-imp...

SRS K-area material storage. Expanding capabilities

International Nuclear Information System (INIS)

Koenig, R.

2013-01-01

In support of the Department of Energy’s continued plans to de-inventory and reduce the footprint of Cold War era weapons’ material production sites, the K-Area Material Storage (KAMS) facility, located in the K-Area Complex (KAC) at the Savannah River Site reservation, has expanded since its startup authorization in 2000 to accommodate DOE’s material consolidation mission. During the facility’s growth and expansion, KAMS will have expanded its authorization capability of material types and storage containers to allow up to 8200 total shipping containers once the current expansion effort completes in 2014. Recognizing the need to safely and cost effectively manage other surplus material across the DOE Complex, KAC is constantly evaluating the storage of different material types within K area. When modifying storage areas in KAC, the Documented Safety Analysis (DSA) must undergo extensive calculations and reviews; however, without an extensive and proven security posture the possibility for expansion would not be possible. The KAC maintains the strictest adherence to safety and security requirements for all the SNM it handles. Disciplined Conduct of Operations and Conduct of Projects are demonstrated throughout this historical overview highlighting various improvements in capability, capacity, demonstrated cost effectiveness and utilization of the KAC as the DOE Center of Excellence for safe and secure storage of surplus SNM.

On the Equisummability of Hermite and Fourier Expansions

Indian Academy of Sciences (India)

We prove an equisummability result for the Fourier expansions and Hermite expansions as well as special Hermite expansions. We also prove the uniform boundedness of the Bochner-Riesz means associated to the Hermite expansions for polyradial functions.

Agricultural land change in the Carpathian ecoregion after the breakdown of socialism and expansion of the European Union

Science.gov (United States)

Griffiths, Patrick; Müller, Daniel; Kuemmerle, Tobias; Hostert, Patrick

2013-12-01

Widespread changes of agricultural land use occurred in Eastern Europe since the collapse of socialism and the European Union’s eastward expansion, but the rates and patterns of recent land changes remain unclear. Here we assess agricultural land change for the entire Carpathian ecoregion in Eastern Europe at 30 m spatial resolution with Landsat data and for two change periods, between 1985-2000 and 2000-2010. The early period is characterized by post-socialist transition processes, the late period by an increasing influence of EU politics in the region. For mapping and change detection, we use a machine learning approach (random forests) on image composites and variance metrics which were derived from the full decadal archive of Landsat imagery. Our results suggest that cropland abandonment was the most prevalent change process, but we also detected considerable areas of grassland conversion and forest expansion on non-forest land. Cropland abandonment was most extensive during the transition period and predominantly occurred in marginal areas with low suitability for agriculture. Conversely, we observed substantial recultivation of formerly abandoned cropland in high-value agricultural areas since 2000. Hence, market forces increasingly adjust socialist legacies of land expansive production and agricultural land use clusters in favorable areas while marginal lands revert to forest.

Integrating future scenario‐based crop expansion and crop conditions to map switchgrass biofuel potential in eastern Nebraska, USA

Science.gov (United States)

Gu, Yingxin; Wylie, Bruce K.

2018-01-01

Switchgrass (Panicum virgatum) has been evaluated as one potential source for cellulosic biofuel feedstocks. Planting switchgrass in marginal croplands and waterway buffers can reduce soil erosion, improve water quality, and improve regional ecosystem services (i.e. it serves as a potential carbon sink). In previous studies, we mapped high risk marginal croplands and highly erodible cropland buffers that are potentially suitable for switchgrass development, which would improve ecosystem services and minimally impact food production. In this study, we advance our previous study results and integrate future crop expansion information to develop a switchgrass biofuel potential ensemble map for current and future croplands in eastern Nebraska. The switchgrass biomass productivity and carbon benefits (i.e. NEP: net ecosystem production) for the identified biofuel potential ensemble areas were quantified. The future scenario‐based (‘A1B’) land use and land cover map for 2050, the US Geological Survey crop type and Compound Topographic Index (CTI) maps, and long‐term (1981–2010) averaged annual precipitation data were used to identify future crop expansion regions that are suitable for switchgrass development. Results show that 2528 km2 of future crop expansion regions (~3.6% of the study area) are potentially suitable for switchgrass development. The total estimated biofuel potential ensemble area (including cropland buffers, marginal croplands, and future crop expansion regions) is 4232 km2 (~6% of the study area), potentially producing 3.52 million metric tons of switchgrass biomass per year. Converting biofuel ensemble regions to switchgrass leads to potential carbon sinks (the total NEP for biofuel potential areas is 0.45 million metric tons C) and is environmentally sustainable. Results from this study improve our understanding of environmental conditions and ecosystem services of current and future cropland systems in eastern Nebraska and provide

Apparent luminosity function of galaxies to the twenty-first magnitude

International Nuclear Information System (INIS)

Brown, G.S.

1979-01-01

Galaxy counts to limiting magnitudes B=17.7 to 21.0 in 13 selected areas in the north galactic polar cap are presented. The photographs were taken with a reducing camera at the Cassegrain focus of the 91 cm and 205 cm reflectors of McDonald Observatory. Both galaxy and star images were counted and recorded. On each plate a few stars and galaxies were marked as representative of the plate limit. Selected brighter galaxies and stars were measured photoelectrically to fix the zero points. The B magnitude limits of each plate for stars and galaxies are obtained by a combination of photoelectric and photographic photometry. The resulting apparent luminosity functions of galaxies and stars are compared with earlier data. Sources of error in the counts are discussed in detail

Energy flow in a bound electromagnetic field: resolution of apparent paradoxes

International Nuclear Information System (INIS)

Kholmetskii, A L; Yarman, T

2008-01-01

In this paper, we present a resolution of apparent paradoxes formulated in (Kholmetskii A L 2006 Apparent paradoxes in classical electrodynamics: the energy-momentum conservation law for a bound electromagnetic field Eur. J. Phys. 27 825-38; Kholmetskii A L and Yarman T 2008 Apparent paradoxes in classical electrodynamics: a fluid medium in an electromagnetic field Eur. J. Phys. 29 1127) and dealing with the energy flux in a bound electromagnetic field

Assessment for salinized wasteland expansion and land use change using GIS and remote sensing in the west part of northeast China.

Science.gov (United States)

Li, Xiaoyan; Wang, Zongming; Song, Kaishan; Zhang, Bai; Liu, Dianwei; Guo, Zhixing

2007-08-01

Due to human impact under climatic variations, western part of Northeast China has suffered substantial land degradation during past decades. This paper presents an integrated study of expansion process of salinized wasteland in Da'an County, a typical salt-affected area in Northeast China, by using Geographic Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of salinized wasteland expansion from 1954 to 2004, and land use/cover changes during this period. During the past 50 years, the salinized wasteland in study area have increased by 135,995 ha, and in 2004 covers 32.31% of the total area, in the meantime grassland has decreased by 104,697 ha and in 2004 covers only 13.15% of the study area. Grasslands, croplands and swamplands were found the three main land use types converted into salinized wasteland. Land use/cover changes shows that between 1954 and 2004, 48.6% of grasslands, 42.5% of swamplands, and 14.1% of croplands were transformed into salinized wasteland, respectively. Lastly, the major factors influencing salinized wasteland expansion and land use/cover changes were also explored. In general, climatic factors supplied a potential environment for soil salinization. Human-related factors, such as policy, population, overgrazing, and intensified and unreasonable utilization of land and water resources are the main causes of salinized wasteland expansion.

Plasma expansion: fundamentals and applications

International Nuclear Information System (INIS)

Engeln, R; Mazouffre, S; Vankan, P; Bakker, I; Schram, D C

2002-01-01

The study of plasma expansion is interesting from a fundamental point of view as well as from a more applied point of view. We here give a short overview of the way properties like density, velocity and temperature behave in an expanding thermal plasma. Experimental data show that the basic phenomena of plasma expansion are to some extent similar to those of the expansion of a hot neutral gas. From the application point of view, we present first results on the use of an expanding thermal plasma in the plasma-activated catalysis of ammonia, from N 2 -H 2 mixtures

40 CFR 258.13 - Fault areas.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Fault areas. 258.13 Section 258.13... SOLID WASTE LANDFILLS Location Restrictions § 258.13 Fault areas. (a) New MSWLF units and lateral expansions shall not be located within 200 feet (60 meters) of a fault that has had displacement in Holocene...

On genus expansion of superpolynomials

Energy Technology Data Exchange (ETDEWEB)

Mironov, Andrei, E-mail: mironov@itep.ru [Lebedev Physics Institute, Moscow 119991 (Russian Federation); ITEP, Moscow 117218 (Russian Federation); National Research Nuclear University MEPhI, Moscow 115409 (Russian Federation); Morozov, Alexei, E-mail: morozov@itep.ru [ITEP, Moscow 117218 (Russian Federation); National Research Nuclear University MEPhI, Moscow 115409 (Russian Federation); Sleptsov, Alexei, E-mail: sleptsov@itep.ru [ITEP, Moscow 117218 (Russian Federation); Laboratory of Quantum Topology, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); KdVI, University of Amsterdam (Netherlands); Smirnov, Andrey, E-mail: asmirnov@math.columbia.edu [ITEP, Moscow 117218 (Russian Federation); Columbia University, Department of Mathematics, New York (United States)

2014-12-15

Recently it was shown that the (Ooguri–Vafa) generating function of HOMFLY polynomials is the Hurwitz partition function, i.e. that the dependence of the HOMFLY polynomials on representation R is naturally captured by symmetric group characters (cut-and-join eigenvalues). The genus expansion and expansion through Vassiliev invariants explicitly demonstrate this phenomenon. In the present paper we claim that the superpolynomials are not functions of such a type: symmetric group characters do not provide an adequate linear basis for their expansions. Deformation to superpolynomials is, however, straightforward in the multiplicative basis: the Casimir operators are β-deformed to Hamiltonians of the Calogero–Moser–Sutherland system. Applying this trick to the genus and Vassiliev expansions, we observe that the deformation is fully straightforward only for the thin knots. Beyond the family of thin knots additional algebraically independent terms appear in the Vassiliev and genus expansions. This can suggest that the superpolynomials do in fact contain more information about knots than the colored HOMFLY and Kauffman polynomials. However, even for the thin knots the beta-deformation is non-innocent: already in the simplest examples it seems inconsistent with the positivity of colored superpolynomials in non-(anti)symmetric representations, which also happens in I. Cherednik's (DAHA-based) approach to the torus knots.

Chemical and mechanical changes during leaf expansion of four woody species of dry Restinga woodland.

Science.gov (United States)

Schlindwein, C C D; Fett-Neto, A G; Dillenburg, L R

2006-07-01

Young leaves are preferential targets for herbivores, and plants have developed different strategies to protect them. This study aimed to evaluate different leaf attributes of presumed relevance in protection against herbivory in four woody species (Erythroxylum argentinum, Lithrea brasiliensis, Myrciaria cuspidata, and Myrsine umbellata), growing in a dry restinga woodland in southern Brazil. Evaluation of leaf parameters was made through single-point sampling of leaves (leaf mass per area and leaf contents of nitrogen, carbon, and pigments) at three developmental stages and through time-course sampling of expanding leaves (area and strength). Leaves of M. umbellata showed the highest leaf mass per area (LMA), the largest area, and the longest expansion period. On the other extreme, Myrc. cuspidata had the smallest LMA and leaf size, and the shortest expansion period. Similarly to L. brasiliensis, it displayed red young leaves. None of the species showed delayed-greening, which might be related to the high-irradiance growth conditions. Nitrogen contents reduced with leaf maturity and reached the highest values in the young leaves of E. argentinum and Myrc. cuspidata and the lowest in M. umbellata. Each species seems to present a different set of protective attributes during leaf expansion. Myrciaria cuspidata appears to rely mostly on chemical defences to protect its soft leaves, and anthocyanins might play this role at leaf youth, while M. umbellata seems to invest more on mechanical defences, even at early stages of leaf growth, as well as on a low allocation of nitrogen to the leaves. The other species display intermediate characteristics.

Analysis of Urban Expansion of the Resort City of Al Ain Using Remote Sensing and GIS

Science.gov (United States)

Issa, S.; Al Shuwaihi, A.

2009-12-01

The urban growth of AL Ain city has been investigated using remote sensing data for three different dates, 1972, 1990 and 2000. We used three Landsat images together with socio-economic data in a post-classification analysis to map the spatial dynamics of land use/cover changes and identify the urbanization process in Al Ain resort city, United Arab Emirates. Land use/cover statistics, extracted from Landsat Multi-spectral Scanner (MSS). Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM +) images for 1972. 1990 and 2000 respectively, revealed that the built-up area has expanded by about 170.53km2. The city was found to have a tendency for major expansion in four different directions: along the Abu Dhabi highway, along Dubai highway, Myziad direction and Hafeet recreational area. Expansion in any direction was found to be governed by the availability of road network, suitability for construction, utilities, economic activities, geographical constraints, and legal factors (boundary with Sultanate of Oman). The road network in particular has influenced the spatial patterns and structure of urban development, so that the expansion of the built-up areas has assumed an accretive as well as linear growth along the major roads. The research concludes that the development is based on conservation of agricultural areas (oases) and reclamation of the desert for farming and agricultural activities. The integration of remote sensing and GIS was found to be effective in monitoring LULC changes and providing valuable information necessary for planning and research.

On summation of perturbation expansions

International Nuclear Information System (INIS)

Horzela, A.

1985-04-01

The problem of the restoration of physical quantities defined by divergent perturbation expansions is analysed. The Pad'e and Borel summability is proved for alternating perturbation expansions with factorially growing coefficients. The proof is based on the methods of the classical moments theory. 17 refs. (author)

Ultraintense laser interaction with nanoscale target: a simple model for layer expansion and ion acceleration

International Nuclear Information System (INIS)

Albright, Brian J.; Yin, Lin; Hegelich, Bjoorn M.; Bowers, Kevin J.; Huang, Chengkun; Fernandez, Juan C.; Flippo, Kirk A.; Gaillard, Sandrine; Kwan, Thomas J.T.; Henig, Andreas; Habs, Dieter

2009-01-01

A simple model has been derived for the expansion of a thin (up to 100s of nm thickness), solid-density target driven by an u.ltraintense laser. In this regime, new ion acceleration mechanisms, such as the Break-Out Afterburner (BOA) (1), emerge with the potential to dramatically improve energy, efficiency, and energy spread of laser-driven ion beams. Such beams have been proposed (2) as drivers for fast ignition inertial confinement fusion (3). Analysis of kinetic simulations of the BOA shows two dislinct times that bound the period of enhanced acceleration: t 1 , when the target becomes relativistically transparent to the laser, and t 2 , when the target becomes classically underdense and the enhanced acceleration terminates. A silllple dynamical model for target expansion has been derived that contains both the early, one-dimensional (lD) expansion of the target as well as three-dimensional (3D) expansion of the plasma at late times, The model assumes that expansion is slab-like at the instantaneous ion sound speed and requires as input target composition, laser intensity, laser spot area, and the efficiency of laser absorption into electron thermal energy.

OPEC future capacity expansions

International Nuclear Information System (INIS)

Sandrea, I.

2005-01-01

This conference presentation examined OPEC future capacity expansions including highlights from 2000-2004 from the supply perspective and actions by OPEC; OPEC spare capacity in 2005/2006; medium-term capacity expansion and investments; long-term scenarios, challenges and opportunities; and upstream policies in member countries. Highlights from the supply perspective included worst than expected non-OPEC supply response; non-OPEC supply affected by a number of accidents and strikes; geopolitical tensions; and higher than expected demand for OPEC crude. OPEC's actions included closer relationship with other producers and consumers; capacity expansions in 2004 and 2005/2006; and OPEC kept the market well supplied with crude in 2004. The presentation also provided data using graphical charts on OPEC net capacity additions until 2005/2006; OPEC production versus spare capacity from 2003 to 2005; OPEC production and capacity to 2010; and change in required OPEC production from 2005-2020. Medium term expansion to 2010 includes over 60 projects. Medium-term risks such as project execution, financing, costs, demand, reserves, depletion, integration of Iraq, and geopolitical tensions were also discussed. The presentation concluded that in the long term, large uncertainties remain; the peak of world supply is not imminent; and continued and enhanced cooperation is essential to market stability. tabs., figs

Identifying the driving forces of urban expansion and its environmental impact in Jakarta-Bandung mega urban region

Science.gov (United States)

Pravitasari, A. E.; Rustiadi, E.; Mulya, S. P.; Setiawan, Y.; Fuadina, L. N.; Murtadho, A.

2018-05-01

The socio-economic development in Jakarta-Bandung Mega Urban Region (JBMUR) caused the increasing of urban expansion and led to a variety of environmental damage such as uncontrolled land use conversion and raising anthropogenic disaster. The objectives of this study are: (1) to identify the driving forces of urban expansion that occurs on JBMUR and (2) to analyze the environmental quality decline on JBMUR by producing time series spatial distribution map and spatial autocorrelation of floods and landslide as the proxy of anthropogenic disaster. The driving forces of urban expansion in this study were identified by employing Geographically Weighted Regression (GWR) model using 6 (six) independent variables, namely: population density, percentage of agricultural land, distance to the center of capital city/municipality, percentage of household who works in agricultural sector, distance to the provincial road, and distance to the local road. The GWR results showed that local demographic, social and economic factors including distance to the road spatially affect urban expansion in JBMUR. The time series spatial distribution map of floods and landslide event showed the spatial cluster of anthropogenic disaster in some areas. Through Local Moran Index, we found that environmental damage in one location has a significant impact on the condition of its surrounding area.

On Learning Ring-Sum-Expansions

DEFF Research Database (Denmark)

Fischer, Paul; Simon, H. -U.

1992-01-01

The problem of learning ring-sum-expansions from examples is studied. Ring-sum-expansions (RSE) are representations of Boolean functions over the base {#123;small infinum, (+), 1}#125;, which reflect arithmetic operations in GF(2). k-RSE is the class of ring-sum-expansions containing only monomials...... of length at most k:. term-RSE is the class of ring-sum-expansions having at most I: monomials. It is shown that k-RSE, k>or=1, is learnable while k-term-RSE, k>2, is not learnable if RPnot=NP. Without using a complexity-theoretical hypothesis, it is proven that k-RSE, k>or=1, and k-term-RSE, k>or=2 cannot...... be learned from positive (negative) examples alone. However, if the restriction that the hypothesis which is output by the learning algorithm is also a k-RSE is suspended, then k-RSE is learnable from positive (negative) examples only. Moreover, it is proved that 2-term-RSE is learnable by a conjunction...

The bootstrap and edgeworth expansion

CERN Document Server

Hall, Peter

1992-01-01

This monograph addresses two quite different topics, in the belief that each can shed light on the other. Firstly, it lays the foundation for a particular view of the bootstrap. Secondly, it gives an account of Edgeworth expansion. Chapter 1 is about the bootstrap, witih almost no mention of Edgeworth expansion; Chapter 2 is about Edgeworth expansion, with scarcely a word about the bootstrap; and Chapters 3 and 4 bring these two themes together, using Edgeworth expansion to explore and develop the properites of the bootstrap. The book is aimed a a graduate level audience who has some exposure to the methods of theoretical statistics. However, technical details are delayed until the last chapter (entitled "Details of Mathematical Rogour"), and so a mathematically able reader without knowledge of the rigorous theory of probability will have no trouble understanding the first four-fifths of the book. The book simultaneously fills two gaps in the literature; it provides a very readable graduate level account of t...

Asymptotic freedom, confinement, and the convergence of the perturbation expansion in quantum chromodynamics

International Nuclear Information System (INIS)

Muzinich, I.J.

1980-01-01

The quark model of hadrons, when all constituents and gluons are included, has the possibility of accommodating not only what are conventionally accepted quark model states but also exotics of various kinds and eventually nuclei themselves. Recently, a considerable theoretical framework has evolved around quarks and gluons known as quantum chromodynamics. This theory is still at a primitive level as far as our ability to perform calculations. However, it is the only possible field theory that contains any hope of understanding both quark freedom at high energies and their strong binding within hadrons. I present a possible viewpoint on how both features could be true without apparent conflict. I also make some speculation on the nature of the perturbation expansion in such a world. What these speculations lack in originally I hope is compensated for by clarity

76 FR 40688 - Foreign-Trade Zone 71-Windsor Locks, CT Application for Expansion

Science.gov (United States)

2011-07-11

... Locks, CT Application for Expansion An application has been submitted to the Foreign-Trade Zones Board... 2 (390 acres)--within the 600-acre New England Tradeport business park located at the intersection... distribution services to area businesses. No specific manufacturing authority is being requested at this time...

Fuel Thermal Expansion (FTHEXP)

International Nuclear Information System (INIS)

Reymann, G.A.

1978-07-01

A model is presented which deals with dimensional changes in LWR fuel pellets caused by changes in temperature. It is capable of dealing with any combination of UO 2 and PuO 2 in solid, liquid or mixed phase states, and includes expansion due to the solid-liquid phase change. The function FTHEXP models fuel thermal expansion as a function of temperature, fraction of PuO 2 , and the fraction of fuel which is molten

Status of the expansion of the CYGNUS array at Los Alamos

International Nuclear Information System (INIS)

Berley, D.; Chang, C.Y.; Dingus, B.L.

1989-01-01

The CYGNUS air shower array, located in Los Alamos, New Mexico, has been operating since April, 1986. The expansion of the array from 108 to 200 counters is described along with the increase in muon detection area. The new array, to be fully operational by the end of 1989, will have three times the sensitivity to UHE sources. 5 refs., 2 figs

Node-Expansion Operators for the UCT Algorithm

Science.gov (United States)

Yajima, Takayuki; Hashimoto, Tsuyoshi; Matsui, Toshiki; Hashimoto, Junichi; Spoerer, Kristian

Recent works on the MCTS and UCT framework in the domain of Go focused on introducing knowledge to the playout and on pruning variations from the tree, but so far node expansion has not been investigated. In this paper we show that delaying expansion according to the number of the siblings delivers a gain of more than 92% when compared to normal expansion. We propose three improvements; one that uses domain knowledge and two that are domain-independent methods. Experimental results show that all advanced operators significantly improve the UCT performance when compared to the basic delaying expansion. From the results we may conclude that the new expansion operators are an appropriate means to improve the UCT algorithm.

One Stage Reconstruction of Skull Exposed by Burn Injury Using a Tissue Expansion Technique

Directory of Open Access Journals (Sweden)

Jae Young Cho

2012-03-01

Full Text Available BackgroundAn area of the skull exposed by burn injury has been covered by various methods including local flap, skin graft, or free flap surgery. Each method has disadvantages, such as postoperative alopecia or donor site morbidities. Due to the risk of osteomyelitis in the injured skull during the expansion period, tissue expansion was excluded from primary reconstruction. However, successful primary reconstruction was possible in burned skull by tissue expansion.MethodsFrom January 2000 to 2011, tissue expansion surgery was performed on 10 patients who had sustained electrical burn injuries. In the 3 initial cases, removal of the injured part of the skull and a bone graft was performed. In the latter 7 cases, the injured skull tissue was preserved and covered with a scalp flap directly to obtain natural bone healing and bone remodeling.ResultsThe mean age of patients was 49.9±12.2 years, with 8 male and 2 female. The size of the burn wound was an average of 119.6±36.7 cm2. The mean expansion duration was 65.5±5.6 days, and the inflation volume was an average of 615±197.6 mL. Mean defect size was 122.2±34.9 cm2. The complications including infection, hematoma, and the exposure of the expander were observed in 4 cases. Nonetheless, only 1 case required revision.ConclusionsSuccessful coverage was performed by tissue expansion surgery in burned skull primarily and no secondary reconstruction was needed. Although the risks of osteomyelitis during the expansion period were present, constant coverage of the injured skull and active wound treatment helped successful primary reconstruction of burned skull by tissue expansion.

Thermal expansion behavior of fluor-chlorapatite crystalline solutions

Science.gov (United States)

Hovis, G.; Harlov, D.; Gottschalk, M.; Hudacek, W.; Wildermuth, S.

2009-04-01

the fluor-chlorapatite series is little affected by composition. This contrasts with relationships in alkali feldspars (Hovis and coworkers, 1997, 1999), which show that K-rich feldspars expand less than Na-rich feldspars. It contrasts also with the behavior of additional AlSi3 feldspars (Hovis and others, 2008), in which room-temperature chemical expansion limits the degree to which the structure can expand thermally. It also differs from expansion in kalsilite crystalline solutions (Hovis and coworkers, 2003, 2006), which depends on K:Na ratio. Among the minerals we have studied previously, only nepheline displays expansion behavior similar to that of fluor-chlorapatite crystalline solutions in that thermal expansion shows little sensitivity to composition. In AlSi3 feldspars and kalsilite one observes a single crystallographically distinct alkali site and a dominating SiO4 tetrahedral framework that limits the vibrational characteristics of the alkali-site occupant(s). Fluor-chlorapatite crystalline solutions have no such structural framework. Moreover, the anion site in the latter changes structural character in the transition from fluorapatite to chlorapatite. This flexibility apparently allows anion vibrational characteristics, coupled with those of Ca polyhedral components, to change continuously and in a compensating manner across the series. The thermal expansion data also imply that volumes of F-Cl mixing in fluor-chlorapatite are constant from room temperature to 1000 °C. References: Cherniak, D.J. (2000) Rare earth element diffusion in apatite. Geochimica et Cosmochimica Acta 64, 3871-3885. Harlov, D.E. and Förster, H-J. (2002) High grade fluid metasomatism on both a local and regional Scale: the Seward Peninsula, Alaska and the Ivrea-Verbano Zone, Northern Italy Part II: phosphate mineral chemistry. Journal of Petrology 43, 801-824. Holland, T.J.B. and Redfern, S.A.T. (1997) Unit-cell refinement: Changing the dependent variable, and use of regression

Thermal expansion in small metallic particles

International Nuclear Information System (INIS)

Ivanov, A.S.

1985-01-01

An anomalously low thermal expansion observable in small particles is attributed to extending effect of the shell. It is shown that the coefficient of thermal expansion of the oxide-film-coated aluminium particles calculated using elastic constants and coefficients of thermal expansion of massive materials agres well with those measured experimentally. The linear dilatation of the shell, its stress to rupture and the values of the structural tension are estimated vs the temperature

Strategic environmental assessment for sustainable expansion of palm oil biofuels in Brazilian north region

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Carolina

2010-09-15

Biofuels development in Brazil is a key factor for the environment and sustainable development of the country. Brazil has great potential of available areas and has favourable climate and geography for biofuel production, such as palm oil, soy, sugar cane, etc. This research aims to evaluate palm oil production and expansion in Para state, in the north of Brazil and also Amazonian territory. Degraded land will be evaluated through remote sensing, because palm oil crops should be placed in these lands, and secondly, expansion scenarios would be created. This PhD research will be a decision support tool for public policies.

Expansion and growth in Chinese cities, 1978–2010

International Nuclear Information System (INIS)

Schneider, A; Mertes, C M

2014-01-01

It has long been recognized that compact versus more sprawling urban forms can have very different environmental impacts. As the Chinese population continues to rapidly urbanize, the size, shape, and configuration of cities in China will undoubtedly change to accommodate expansion of housing, industry, and commerce, causing direct and indirect environmental impacts at multiple scales. It is therefore imperative to understand how urban areas are evolving as socio-economic reforms in China are implemented across different regions. This paper compares trends in 142 Chinese cities (including 17 agglomerations) to understand urban expansion and population growth following reforms, 1978–2010. The results show that cities tripled in size, while doubling in population over the same period. In coastal areas targeted by early policies, urban land increased 4–5 times since 1978, for all city sizes. Large agglomerations are the primary consumers of land in coastal and western regions, each adding an average of 450 km 2 during the study period, while small-medium cities consumed an average 20 km 2 . Although populations in these agglomerations increased an average 1.3 million, 2000–2010, cities within 100 km of each agglomeration grew >1.8 million collectively. Proximity to large agglomerations contributed to the growth of small-medium cities, especially in western regions. (paper)

[Tissular expansion in giant congenital nevi treatment].

Science.gov (United States)

Nguyen Van Nuoi, V; Francois-Fiquet, C; Diner, P; Sergent, B; Zazurca, F; Franchi, G; Buis, J; Vazquez, M-P; Picard, A; Kadlub, N

2014-08-01

Surgical management of giant melanotic naevi remains a surgical challenge. Tissue expansion provides tissue of the same quality for the repair of defects. The aim of this study is to review tissular expansion for giant melanotic naevi. We conducted a retrospective study from 2000 to 2012. All children patients who underwent a tissular expansion for giant congenital naevi had been included. Epidemiological data, surgical procedure, complication rate and results had been analysed. Thirty-tree patients had been included; they underwent 61 procedures with 79 tissular-expansion prosthesis. Previous surgery, mostly simple excision had been performed before tissular expansion. Complete naevus excision had been performed in 63.3% of the cases. Complications occurred in 45% of the cases, however in 50% of them were minor. Iterative surgery increased the complication rate. Tissular expansion is a valuable option for giant congenital naevus. However, complication rate remained high, especially when iterative surgery is needed. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Truncal anaesthesia of the maxillary nerve for outpatient surgically assisted rapid maxillary expansion.

Science.gov (United States)

Robiony, M; Demitri, V; Costa, F; Politi, M; Cugini, U

1998-10-01

We present our experience of transcutaneous truncal anaesthesia of the maxillary nerve in association with transmucosal anaesthesia of the sphenopalatine ganglion in surgically assisted rapid maxillary expansion. Twelve patients with a skeletal transverse discrepancy of the maxilla were treated in our department from 1994 to 1995. Maxillary transcutaneous nerve block was done with a Quincke 8 cm spinal needle together with transmucosal anaesthesia of the sphenopalatine ganglion. Mepivacaine without adrenaline and sodium bicarbonate 1/10 was used for truncal anaesthesia and lidocaine-prilocaine cream for transmucosal anaesthesia. A Le Fort I osteotomy, lateral nasal wall osteotomy, pterygomaxillary osteotomy, and a palatal osteotomy were done for all patients before the maxillary expansion. Total anaesthesia of the maxillary area facilitated the operations and appreciably reduced the amount of postoperative pain. The ease of achieving effective anaesthesia before and after operation and the absence of side-effects make this form of anaesthetic particularly useful in surgically assisted rapid maxillary expansion.

Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications.

Science.gov (United States)

Chen, Jun; Hu, Lei; Deng, Jinxia; Xing, Xianran

2015-06-07

Negative thermal expansion (NTE) is an intriguing physical property of solids, which is a consequence of a complex interplay among the lattice, phonons, and electrons. Interestingly, a large number of NTE materials have been found in various types of functional materials. In the last two decades good progress has been achieved to discover new phenomena and mechanisms of NTE. In the present review article, NTE is reviewed in functional materials of ferroelectrics, magnetics, multiferroics, superconductors, temperature-induced electron configuration change and so on. Zero thermal expansion (ZTE) of functional materials is emphasized due to the importance for practical applications. The NTE functional materials present a general physical picture to reveal a strong coupling role between physical properties and NTE. There is a general nature of NTE for both ferroelectrics and magnetics, in which NTE is determined by either ferroelectric order or magnetic one. In NTE functional materials, a multi-way to control thermal expansion can be established through the coupling roles of ferroelectricity-NTE, magnetism-NTE, change of electron configuration-NTE, open-framework-NTE, and so on. Chemical modification has been proved to be an effective method to control thermal expansion. Finally, challenges and questions are discussed for the development of NTE materials. There remains a challenge to discover a "perfect" NTE material for each specific application for chemists. The future studies on NTE functional materials will definitely promote the development of NTE materials.

Meta-Analysis of Predictive Significance of the Black Hole Sign for Hematoma Expansion in Intracerebral Hemorrhage.

Science.gov (United States)

Zheng, Jun; Yu, Zhiyuan; Guo, Rui; Li, Hao; You, Chao; Ma, Lu

2018-04-27

Hematoma expansion is related to unfavorable prognosis in intracerebral hemorrhage (ICH). The black hole sign is a novel marker on non-contrast computed tomography for predicting hematoma expansion. However, its predictive values are different in previous studies. Thus, this meta-analysis was conducted to evaluate the predictive significance of the black hole sign for hematoma expansion in ICH. A systematic literature search was performed. Original researches on the association between the black hole sign and hematoma expansion in ICH were included. Sensitivity and specificity were pooled to assess the predictive accuracy. Summary receiver operating characteristics curve (SROC) was developed. Deeks' funnel plot asymmetry test was used to assess the publication bias. Five studies with a total of 1495 patients were included in this study. The pooled sensitivity and specificity of the black hole sign for predicting hematoma expansion were 0.30 and 0.91, respectively. The area under the curve was 0.78 in SROC curve. There was no significant publication bias. This meta-analysis shows that the black hole sign is a helpful imaging marker for predicting hematoma expansion in ICH. Although the black hole sign has a relatively low sensitivity, its specificity is relatively high. Copyright © 2018 Elsevier Inc. All rights reserved.

Agricultural land change in the Carpathian ecoregion after the breakdown of socialism and expansion of the European Union

International Nuclear Information System (INIS)

Griffiths, Patrick; Müller, Daniel; Kuemmerle, Tobias; Hostert, Patrick

2013-01-01

Widespread changes of agricultural land use occurred in Eastern Europe since the collapse of socialism and the European Union’s eastward expansion, but the rates and patterns of recent land changes remain unclear. Here we assess agricultural land change for the entire Carpathian ecoregion in Eastern Europe at 30 m spatial resolution with Landsat data and for two change periods, between 1985–2000 and 2000–2010. The early period is characterized by post-socialist transition processes, the late period by an increasing influence of EU politics in the region. For mapping and change detection, we use a machine learning approach (random forests) on image composites and variance metrics which were derived from the full decadal archive of Landsat imagery. Our results suggest that cropland abandonment was the most prevalent change process, but we also detected considerable areas of grassland conversion and forest expansion on non-forest land. Cropland abandonment was most extensive during the transition period and predominantly occurred in marginal areas with low suitability for agriculture. Conversely, we observed substantial recultivation of formerly abandoned cropland in high-value agricultural areas since 2000. Hence, market forces increasingly adjust socialist legacies of land expansive production and agricultural land use clusters in favorable areas while marginal lands revert to forest. (letter)

Applications of the large mass expansion

International Nuclear Information System (INIS)

Fleischer, J.; Kotikov, A.V.; ); Veretin, O.L.

1998-01-01

The method of the large mass expansion (LME) is investigated for selfenergy and vertex functions in two-loop order. It has the technical advantage that in many cases the expansion coefficients can be expressed analytically. As long as only one non-zero external momentum squared, q 2 , is involved also the Taylor expansion (TE) w.r.t. small q 2 yields high precision results in a domain sufficient for most applications. In the case of only one non-zero mass M and only one external momentum squared, the expansion w.r.t. q 2 /M 2 is identical for the TE and the LME. In this case the combined techniques yield analytic expressions for many diagrams, which are quite easy to handle numerically. (author)

Foraminiferal Range Expansions: The Mediterranean Sea as a natural laboratory for climate induced invasions

Science.gov (United States)

Hortense Mouanga, Gloria; Langer, Martin R.

2015-04-01

Climate change and biological invasions are key processes that modify biodiversity. One of the most severely affected areas of global change is the Mediterranean Sea, where global warming and the opening of the Suez Canal triggered a mass invasion of tropical Red Sea taxa into Mediterranean territories. Climate models prognosticate that the Mediterranean Sea will be one of the most affected ocean regions and may thus serve as a natural laboratory of future global changes. Among the key taxa that are rapidly expanding their latitudinal range in the Mediterranean Sea are symbiont-bearing foraminifera of the genus Amphistegina. Their range expansion strongly correlates with rising sea surface temperatures and mirrors processes of global change. Amphisteginid foraminifera are among the most prolific foraminiferal species and contribute significantly to shallow-water carbonate sediments. Given their prominent environmental role, rapid biogeographic range expansion, and impact on native ecosystems, amphisteginid range expansion and invasion into new territory are likely to trigger changes in ecosystem functioning. Among the uncertainties, it is not known whether all parts of the Mediterranean will be affected equally and to what extent amphisteginid invasions will impact native biotas. We have initiated a new baseline study to explore the effects of invasive amphisteginids on native foraminiferal biotas and to monitor expansion rates and effects on ecosystem functioning along the current range expansion front. We will present new data on recent shift along the range expansion front and discuss cascading effects on community structures and species richness of native foraminiferal biotas. The magnitude and effects that climate change will have on the Mediterranean foraminiferal faunas may ultimately serve as an example of what would happen along expansion fronts in global oceans.

Hematoma Expansion Following Acute Intracerebral Hemorrhage

Science.gov (United States)

Brouwers, H. Bart; Greenberg, Steven M.

2013-01-01

Intracerebral hemorrhage, the most devastating form of stroke, has no specific therapy proven to improve outcome by randomized controlled trial. Location and baseline hematoma volume are strong predictors of mortality, but are non-modifiable by the time of diagnosis. Expansion of the initial hematoma is a further marker of poor prognosis that may be at least partly preventable. Several risk factors for hematoma expansion have been identified, including baseline ICH volume, early presentation after symptom onset, anticoagulation, and the CT angiography spot sign. Although the biological mechanisms of hematoma expansion remain unclear, accumulating evidence supports a model of ongoing secondary bleeding from ruptured adjacent vessels surrounding the initial bleeding site. Several large clinical trials testing therapies aimed at preventing hematoma expansion are in progress, including aggressive blood pressure reduction, treatment with recombinant factor VIIa guided by CT angiography findings, and surgical intervention for superficial hematomas without intraventricular extension. Hematoma expansion is so far the only marker of outcome that is amenable to treatment and thus a potentially important therapeutic target. PMID:23466430

The Riddle of the Apparently Hollow Himalaya

Indian Academy of Sciences (India)

The Riddle of the Apparently Hollow Himalaya. Ramesh .... It was as if the Himalayas were hollow inside. ... block would be consistent with the ground elevation in such a ... Alternative models and possible preference: Many refinements of.

Renormalization group and mayer expansions

International Nuclear Information System (INIS)

Mack, G.

1984-01-01

Mayer expansions promise to become a powerful tool in exact renormalization group calculations. Iterated Mayer expansions were sucessfully used in the rigorous analysis of 3-dimensional U (1) lattice gauge theory by Gopfert and the author, and it is hoped that they will also be useful in the 2-dimensional nonlinear σ-model, and elsewhere

Asymptotic expansions for high-contrast elliptic equations

KAUST Repository

Calo, Victor M.; Efendiev, Yalchin R.; Galvis, Juan

2014-01-01

In this paper, we present a high-order expansion for elliptic equations in high-contrast media. The background conductivity is taken to be one and we assume the medium contains high (or low) conductivity inclusions. We derive an asymptotic expansion with respect to the contrast and provide a procedure to compute the terms in the expansion. The computation of the expansion does not depend on the contrast which is important for simulations. The latter allows avoiding increased mesh resolution around high conductivity features. This work is partly motivated by our earlier work in [Domain decomposition preconditioners for multiscale flows in high-contrast media, Multiscale Model Simul. 8 (2010) 1461-1483] where we design efficient numerical procedures for solving high-contrast problems. These multiscale approaches require local solutions and our proposed high-order expansion can be used to approximate these local solutions inexpensively. In the case of a large-number of inclusions, the proposed analysis can help to design localization techniques for computing the terms in the expansion. In the paper, we present a rigorous analysis of the proposed high-order expansion and estimate the remainder of it. We consider both high-and low-conductivity inclusions. © 2014 World Scientific Publishing Company.

Asymptotic expansions for high-contrast elliptic equations

KAUST Repository

Calo, Victor M.

2014-03-01

In this paper, we present a high-order expansion for elliptic equations in high-contrast media. The background conductivity is taken to be one and we assume the medium contains high (or low) conductivity inclusions. We derive an asymptotic expansion with respect to the contrast and provide a procedure to compute the terms in the expansion. The computation of the expansion does not depend on the contrast which is important for simulations. The latter allows avoiding increased mesh resolution around high conductivity features. This work is partly motivated by our earlier work in [Domain decomposition preconditioners for multiscale flows in high-contrast media, Multiscale Model Simul. 8 (2010) 1461-1483] where we design efficient numerical procedures for solving high-contrast problems. These multiscale approaches require local solutions and our proposed high-order expansion can be used to approximate these local solutions inexpensively. In the case of a large-number of inclusions, the proposed analysis can help to design localization techniques for computing the terms in the expansion. In the paper, we present a rigorous analysis of the proposed high-order expansion and estimate the remainder of it. We consider both high-and low-conductivity inclusions. © 2014 World Scientific Publishing Company.

Crude oil pipeline expansion summary

International Nuclear Information System (INIS)

2005-02-01

The Canadian Association of Petroleum Producers has been working with producers to address issues associated with the development of new pipeline capacity from western Canada. This document presents an assessment of the need for additional oil pipeline capacity given the changing mix of crude oil types and forecasted supply growth. It is of particular interest to crude oil producers and contributes to current available information for market participants. While detailed, the underlying analysis does not account for all the factors that may come into play when individual market participants make choices about which expansions they may support. The key focus is on the importance of timely expansion. It was emphasized that if pipeline expansions lags the crude supply growth, then the consequences would be both significant and unacceptable. Obstacles to timely expansion are also discussed. The report reviews the production and supply forecasts, the existing crude oil pipeline infrastructure, opportunities for new market development, requirements for new pipeline capacity and tolling options for pipeline development. tabs., figs., 1 appendix

Expansion dynamics

International Nuclear Information System (INIS)

Knoll, J.

1985-10-01

A quantum dynamical model is suggested which describes the expansion and disassembly phase of highly excited compounds formed in energetic heavy-ion collisions. First applications in two space and one time dimensional model world are discussed and qualitatively compared to standard freeze-out concepts. (orig.)

Effects of city expansion on heat stress under climate change conditions.

Directory of Open Access Journals (Sweden)

Daniel Argüeso

Full Text Available We examine the joint contribution of urban expansion and climate change on heat stress over the Sydney region. A Regional Climate Model was used to downscale present (1990-2009 and future (2040-2059 simulations from a Global Climate Model. The effects of urban surfaces on local temperature and vapor pressure were included. The role of urban expansion in modulating the climate change signal at local scales was investigated using a human heat-stress index combining temperature and vapor pressure. Urban expansion and climate change leads to increased risk of heat-stress conditions in the Sydney region, with substantially more frequent adverse conditions in urban areas. Impacts are particularly obvious in extreme values; daytime heat-stress impacts are more noticeable in the higher percentiles than in the mean values and the impact at night is more obvious in the lower percentiles than in the mean. Urban expansion enhances heat-stress increases due to climate change at night, but partly compensates its effects during the day. These differences are due to a stronger contribution from vapor pressure deficit during the day and from temperature increases during the night induced by urban surfaces. Our results highlight the inappropriateness of assessing human comfort determined using temperature changes alone and point to the likelihood that impacts of climate change assessed using models that lack urban surfaces probably underestimate future changes in terms of human comfort.

Spatial Linkage and Urban Expansion: AN Urban Agglomeration View

Science.gov (United States)

Jiao, L. M.; Tang, X.; Liu, X. P.

2017-09-01

Urban expansion displays different characteristics in each period. From the perspective of the urban agglomeration, studying the spatial and temporal characteristics of urban expansion plays an important role in understanding the complex relationship between urban expansion and network structure of urban agglomeration. We analyze urban expansion in the Yangtze River Delta Urban Agglomeration (YRD) through accessibility to and spatial interaction intensity from core cities as well as accessibility of road network. Results show that: (1) Correlation between urban expansion intensity and spatial indicators such as location and space syntax variables is remarkable and positive, while it decreases after rapid expansion. (2) Urban expansion velocity displays a positive correlation with spatial indicators mentioned above in the first (1980-1990) and second (1990-2000) period. However, it exhibits a negative relationship in the third period (2000-2010), i.e., cities located in the periphery of urban agglomeration developing more quickly. Consequently, the hypothesis of convergence of urban expansion in rapid expansion stage is put forward. (3) Results of Zipf's law and Gibrat's law show urban expansion in YRD displays a convergent trend in rapid expansion stage, small and medium-sized cities growing faster. This study shows that spatial linkage plays an important but evolving role in urban expansion within the urban agglomeration. In addition, it serves as a reference to the planning of Yangtze River Delta Urban Agglomeration and regulation of urban expansion of other urban agglomerations.

Use of pressure manifestations following the water plasma expansion for phytomass disintegration.

Science.gov (United States)

Maroušek, Josef; Kwan, Jason Tai Hong

2013-01-01

A prototype capable of generating underwater high-voltage discharges (3.5 kV) coupled with water plasma expansion was constructed. The level of phytomass disintegration caused by transmission of the pressure shockwaves (50-60 MPa) followed by this expansion was analyzed using gas adsorption techniques. The dynamics of the external surface area and the micropore volume on multiple pretreatment stages of maize silage and sunflower seeds was approximated with robust analytical techniques. The multiple increases on the reaction surface were manifest in up to a 15% increase in cumulative methane production, which was itself manifest in the overall acceleration of the anaerobic fermentation process. Disintegration of the sunflower seeds allowed up to 45% higher oil yields using the same operating pressure.

Can lemmings control the expansion of woody plants on tundra?

Science.gov (United States)

Oksanen, Lauri; Oksanen, Tarja; Olofsson, Johan; Virtanen, Risto; Hoset, Katrine; Tuomi, Maria; Kyrö, Kukka

2013-04-01

The ongoing expansion of woody vegetation in the arctic, due to global warming, creates a positive feed back loop. Increasing abundance of woody plants reduces surface albedo both directly and via speeding up snow melt. Thus a successively greater fraction of incoming solar radiation is absorbed and converted to heat. Browsing mammals - both big and small - can prevent this by consuming woody plants. However, the grazer/browser community of many tundra areas is dominated by brown/Norwegian lemmings (Lemmus spp.) which eat graminoids and mosses and cannot use woody plants as forage. It would seem a priori likely that in such areas, mammalian herbivores speed up the expansion of woody plants by improving the chances of their seedlings to get established. We studied the impact of lemmings on woody plants by constructing lemming proof exclosures within piece high-altitude tundra at Joatkanjávri, northernmost Norway. The exclosures were constructed in 1998, during a period of low lemming densities, in snow-beds, where Norwegian lemmings (L. lemmus) were the only ecologically significant herbivorous mammals. (Reindeer migrate through the area in May, when snow-beds are inaccessible for them; during the fall migration, the area represents a dead end and is therefore avoided.) We chose pairs of maximally similar vegetation patches of 0.5 by 0.5 m and randomly assigned one of each pair to become an exclosure while the other plot was left open. The initial state of the vegetation was documented by the point frequency method. In 2008, after the 2007 lemming outbreak, the same documentation was repeated; thereafter the plots were harvested, the vegetation was sorted to species, oven dried and weighed. Exclusion of lemmings resulted to pronounced increase in community level plant biomass. Evergreen woody plants were especially favored by the exclusion of lemming: their above-ground biomass in exclosures was 14 times as great as their biomass on open reference plots. The

Significance of satellite sign and spot sign in predicting hematoma expansion in spontaneous intracerebral hemorrhage.

Science.gov (United States)

Yu, Zhiyuan; Zheng, Jun; Ali, Hasan; Guo, Rui; Li, Mou; Wang, Xiaoze; Ma, Lu; Li, Hao; You, Chao

2017-11-01

Hematoma expansion is related to poor outcome in spontaneous intracerebral hemorrhage (ICH). Recently, a non-enhanced computed tomography (CT) based finding, termed the 'satellite sign', was reported to be a novel predictor for poor outcome in spontaneous ICH. However, it is still unclear whether the presence of the satellite sign is related to hematoma expansion. Initial computed tomography angiography (CTA) was conducted within 6h after ictus. Satellite sign on non-enhanced CT and spot sign on CTA were detected by two independent reviewers. The sensitivity and specificity of both satellite sign and spot sign were calculated. Receiver-operator analysis was conducted to evaluate their predictive accuracy for hematoma expansion. This study included 153 patients. Satellite sign was detected in 58 (37.91%) patients and spot sign was detected in 38 (24.84%) patients. Among 37 patients with hematoma expansion, 22 (59.46%) had satellite sign and 23 (62.16%) had spot sign. The sensitivity and specificity of satellite sign for prediction of hematoma expansion were 59.46% and 68.97%, respectively. The sensitivity and specificity of spot sign were 62.16% and 87.07%, respectively. The area under the curve (AUC) of satellite sign was 0.642 and the AUC of spot sign was 0.746. (P=0.157) CONCLUSION: Our results suggest that the satellite sign is an independent predictor for hematoma expansion in spontaneous ICH. Although spot sign has the higher predictive accuracy, satellite sign is still an acceptable predictor for hematoma expansion when CTA is unavailable. Copyright © 2017 Elsevier B.V. All rights reserved.

The apparent and effective chloride migration coefficients obtained in migration tests

NARCIS (Netherlands)

Spiesz, P.R.; Brouwers, H.J.H.

2013-01-01

The apparent (Dapp) and effective (Deff) migration coefficients obtained in chloride migration tests are investigated in this study. The presented Dapp profiles in concrete show that the apparent migration coefficient is strongly concentration-dependent. As demonstrated, the binding of chlorides is

Magnetized relativistic electron-ion plasma expansion

Science.gov (United States)

Benkhelifa, El-Amine; Djebli, Mourad

2016-03-01

The dynamics of relativistic laser-produced plasma expansion across a transverse magnetic field is investigated. Based on a one dimensional two-fluid model that includes pressure, enthalpy, and rest mass energy, the expansion is studied in the limit of λD (Debye length) ≤RL (Larmor radius) for magnetized electrons and ions. Numerical investigation conducted for a quasi-neutral plasma showed that the σ parameter describing the initial plasma magnetization, and the plasma β parameter, which is the ratio of kinetic to magnetic pressure are the key parameters governing the expansion dynamics. For σ ≪ 1, ion's front shows oscillations associated to the break-down of quasi-neutrality. This is due to the strong constraining effect and confinement of the magnetic field, which acts as a retarding medium slowing the plasma expansion.

Renormalization group and Mayer expansions

International Nuclear Information System (INIS)

Mack, G.

1984-02-01

Mayer expansions promise to become a powerful tool in exact renormalization group calculations. Iterated Mayer expansions were sucessfully used in the rigorous analysis of 3-dimensional U(1) lattice gauge theory by Goepfert and the author, and it is hoped that they will also be useful in the 2-dimensional nonlinear sigma-model, and elsewhere. (orig.)

Effect of pyloroplasty and fundectomy on the delay of gastric emptying and gastrointestinal transit of liquid elicited by acute blood volume expansion in awake rats

Directory of Open Access Journals (Sweden)

M.C.V. Rêgo

1998-03-01

Full Text Available We evaluated the effects of fundectomy and pyloroplasty on the delay of gastric emptying (GE and gastrointestinal (GI transit of liquid due to blood volume (BV expansion in awake rats. Male Wistar rats (N = 76, 180-250 g were first submitted to fundectomy (N = 26, Heinecke-Mikulicz pyloroplasty (N = 25 or SHAM laparotomy (N = 25. After 6 days, the left external jugular vein was cannulated and the animals were fasted for 24 h with water ad libitum. The test meal was administered intragastrically (1.5 ml of a phenol red solution, 0.5 mg/ml in 5% glucose to normovolemic control animals and to animals submitted to BV expansion (Ringer-bicarbonate, iv infusion, 1 ml/min, volume up to 5% body weight. BV expansion decreased GE and GI transit rates in SHAM laparotomized animals by 52 and 35.9% (P<0.05. Fundectomy increased GE and GI transit rates by 61.1 and 67.7% (P<0.05 and prevented the effect of expansion on GE but not on GI transit (13.9% reduction, P<0.05. Pyloroplasty also increased GE and GI transit rates by 33.9 and 44.8% (P<0.05 but did not prevent the effect of expansion on GE or GI transit (50.7 and 21.1% reduction, P<0.05. Subdiaphragmatic vagotomy blocked the effect of expansion on GE and GI transit in both SHAM laparotomized animals and animals submitted to pyloroplasty. In conclusion 1 the proximal stomach is involved in the GE delay due to BV expansion but is not essential for the establishment of a delay in GI transit, which suggests the activation of intestinal resistances, 2 pyloric modulation was not apparent, and 3 vagal pathways are involved

Primary central nervous system lymphoma and atypical glioblastoma: differentiation using the initial area under the curve derived from dynamic contrast-enhanced MR and the apparent diffusion coefficient

International Nuclear Information System (INIS)

Choi, Yoon Seong; Lee, Ho-Joon; Ahn, Sung Soo; Lee, Seung-Koo; Chang, Jong Hee; Kang, Seok-Gu; Kim, Eui Hyun; Kim, Se Hoon

2017-01-01

To evaluate the ability of the initial area under the curve (IAUC) derived from dynamic contrast-enhanced MR imaging (DCE-MRI) and apparent diffusion coefficient (ADC) in differentiating between primary central nervous system lymphoma (PCNSL) and atypical glioblastoma (GBM). We retrospectively identified 19 patients with atypical GBM (less than 13 % necrosis of the enhancing tumour), and 23 patients with PCNSL. The histogram parameters of IAUC at 30, 60, 90 s (IAUC30, IAUC60, and IAUC90), and ADC were compared between PCNSL and GBM. The diagnostic performances and added values of the IAUC and ADC for differentiating between PCNSL and GBM were evaluated. Interobserver agreement was assessed via intraclass correlation coefficient (ICC). The IAUC and ADC parameters were higher in GBM than in PCNSL. The 90th percentile (p90) of IAUC30 and 10th percentile (p10) of ADC showed the best diagnostic performance. Adding p90 of IAUC30 to p10 of ADC improved the differentiation between PCNSL and GBM (area under the ROC curve [AUC] = 0.886), compared to IAUC30 or ADC alone (AUC = 0.789 and 0.744; P < 0.05 for all). The ICC was 0.96 for p90 of IAUC30. The IAUC may be a useful parameter together with ADC for differentiating between PCNSL and atypical GBM. (orig.)

Primary central nervous system lymphoma and atypical glioblastoma: differentiation using the initial area under the curve derived from dynamic contrast-enhanced MR and the apparent diffusion coefficient

Energy Technology Data Exchange (ETDEWEB)

Choi, Yoon Seong; Lee, Ho-Joon; Ahn, Sung Soo; Lee, Seung-Koo [Yonsei University College of Medicine, Department of Radiology and Research Institute of Radiological Science, Seodaemun-gu, Seoul (Korea, Republic of); Chang, Jong Hee; Kang, Seok-Gu; Kim, Eui Hyun [Yonsei University College of Medicine, Department of Neurosurgery, Seoul (Korea, Republic of); Kim, Se Hoon [Yonsei University College of Medicine, Department of Pathology, Seoul (Korea, Republic of)

2017-04-15

To evaluate the ability of the initial area under the curve (IAUC) derived from dynamic contrast-enhanced MR imaging (DCE-MRI) and apparent diffusion coefficient (ADC) in differentiating between primary central nervous system lymphoma (PCNSL) and atypical glioblastoma (GBM). We retrospectively identified 19 patients with atypical GBM (less than 13 % necrosis of the enhancing tumour), and 23 patients with PCNSL. The histogram parameters of IAUC at 30, 60, 90 s (IAUC30, IAUC60, and IAUC90), and ADC were compared between PCNSL and GBM. The diagnostic performances and added values of the IAUC and ADC for differentiating between PCNSL and GBM were evaluated. Interobserver agreement was assessed via intraclass correlation coefficient (ICC). The IAUC and ADC parameters were higher in GBM than in PCNSL. The 90th percentile (p90) of IAUC30 and 10th percentile (p10) of ADC showed the best diagnostic performance. Adding p90 of IAUC30 to p10 of ADC improved the differentiation between PCNSL and GBM (area under the ROC curve [AUC] = 0.886), compared to IAUC30 or ADC alone (AUC = 0.789 and 0.744; P < 0.05 for all). The ICC was 0.96 for p90 of IAUC30. The IAUC may be a useful parameter together with ADC for differentiating between PCNSL and atypical GBM. (orig.)

expansion method

Indian Academy of Sciences (India)

of a system under investigation is to model the system in terms of some ... The organization of the paper is as follows: In §2, a brief account of the (G /G)- expansion ...... It is interesting to note that from the general results, one can easily recover.

Forest carbon emissions from cropland expansion in the Brazilian Cerrado biome

Science.gov (United States)

Noojipady, Praveen; Morton, C. Douglas; Macedo, N. Marcia; Victoria, C. Daniel; Huang, Chengquan; Gibbs, K. Holly; Edson Bolfe, L.

2017-02-01

Land use, land use change, and forestry accounted for two-thirds of Brazil’s greenhouse gas emissions profile in 2005. Amazon deforestation has declined by more than 80% over the past decade, yet Brazil’s forests extend beyond the Amazon biome. Rapid expansion of cropland in the neighboring Cerrado biome has the potential to undermine climate mitigation efforts if emissions from dry forest and woodland conversion negate some of the benefits of avoided Amazon deforestation. Here, we used satellite data on cropland expansion, forest cover, and vegetation carbon stocks to estimate annual gross forest carbon emissions from cropland expansion in the Cerrado biome. Nearly half of the Cerrado met Brazil’s definition of forest cover in 2000 (≥0.5 ha with ≥10% canopy cover). In areas of established crop production, conversion of both forest and non-forest Cerrado formations for cropland declined during 2003-2013. However, forest carbon emissions from cropland expansion increased over the past decade in Matopiba, a new frontier of agricultural production that includes portions of Maranhão, Tocantins, Piauí, and Bahia states. Gross carbon emissions from cropland expansion in the Cerrado averaged 16.28 Tg C yr-1 between 2003 and 2013, with forest-to-cropland conversion accounting for 29% of emissions. The fraction of forest carbon emissions from Matopiba was much higher; between 2010-2013, large-scale cropland conversion in Matopiba contributed 45% of total Cerrado forest carbon emissions. Carbon emissions from Cerrado-to-cropland transitions offset 5%-7% of the avoided emissions from reduced Amazon deforestation rates during 2011-2013. Comprehensive national estimates of forest carbon fluxes, including all biomes, are critical to detect cross-biome leakage within countries and achieve climate mitigation targets to reduce emissions from land use, land use change, and forestry.

Adiabatic supernova expansion into the circumstellar medium

International Nuclear Information System (INIS)

Band, D.L.; Liang, E.P.

1987-01-01

We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs

Producing a satellite-derived map and modelling Spartina alterniflora expansion for Willapa Bay in Washington State

Science.gov (United States)

Berlin, Cynthia Jane

1998-12-01

This research addresses the identification of the areal extent of the intertidal wetlands of Willapa Bay, Washington, and the evaluation of the potential for exotic Spartina alterniflora (smooth cordgrass) expansion in the bay using a spatial geographic approach. It is hoped that the results will address not only the management needs of the study area but provide a research design that may be applied to studies of other coastal wetlands. Four satellite images, three Landsat Multi-Spectral (MSS) and one Thematic Mapper (TM), are used to derive a map showing areas of water, low, middle and high intertidal, and upland. Two multi-date remote sensing mapping techniques are assessed: a supervised classification using density-slicing and an unsupervised classification using an ISODATA algorithm. Statistical comparisons are made between the resultant derived maps and the U.S.G.S. topographic maps for the Willapa Bay area. The potential for Spartina expansion in the bay is assessed using a sigmoidal (logistic) growth model and a spatial modelling procedure for four possible growth scenarios: without management controls (Business-as-Usual), with moderate management controls (e.g. harvesting to eliminate seed setting), under a hypothetical increase in the growth rate that may reflect favorable environmental changes, and under a hypothetical decrease in the growth rate that may reflect aggressive management controls. Comparisons for the statistics of the two mapping techniques suggest that although the unsupervised classification method performed satisfactorily, the supervised classification (density-slicing) method provided more satisfactory results. Results from the modelling of potential Spartina expansion suggest that Spartina expansion will proceed rapidly for the Business-as-Usual and hypothetical increase in the growth rate scenario, and at a slower rate for the elimination of seed setting and hypothetical decrease in the growth rate scenarios, until all potential

Isobaric Expansion Engines: New Opportunities in Energy Conversion for Heat Engines, Pumps and Compressors

Directory of Open Access Journals (Sweden)

Maxim Glushenkov

2018-01-01

Full Text Available Isobaric expansion (IE engines are a very uncommon type of heat-to-mechanical-power converters, radically different from all well-known heat engines. Useful work is extracted during an isobaric expansion process, i.e., without a polytropic gas/vapour expansion accompanied by a pressure decrease typical of state-of-the-art piston engines, turbines, etc. This distinctive feature permits isobaric expansion machines to serve as very simple and inexpensive heat-driven pumps and compressors as well as heat-to-shaft-power converters with desired speed/torque. Commercial application of such machines, however, is scarce, mainly due to a low efficiency. This article aims to revive the long-known concept by proposing important modifications to make IE machines competitive and cost-effective alternatives to state-of-the-art heat conversion technologies. Experimental and theoretical results supporting the isobaric expansion technology are presented and promising potential applications, including emerging power generation methods, are discussed. It is shown that dense working fluids with high thermal expansion at high process temperature and low compressibility at low temperature make it possible to operate with reasonable thermal efficiencies at ultra-low heat source temperatures (70–100 °C. Regeneration/recuperation of heat can increase the efficiency notably and extend the area of application of these machines to higher heat source temperatures. For heat source temperatures of 200–600 °C, the efficiency of these machines can reach 20–50% thus making them a flexible, economical and energy efficient alternative to many today’s power generation technologies, first of all organic Rankine cycle (ORC.

Decennial plan of expansion 1994-2003

International Nuclear Information System (INIS)

1993-12-01

The Decennial Plan of Expansion 1994-2003 of Electric sector reproduces the results of the studies occurred during the planning cycle of 1992/93 from the Coordinator Groups of the Electric System Planning. Based in the market forecasting, economic-financier and time for finishing the the works, the Decennial Plan of Expansion presents the schedule of the main generation and transmission works for the next ten years, the annual spend in generation, transmission and distribution, the costs of expansion and the evaluation of attending conditions in electric system in Brazil. (C.G.C.)

In vitro evaluation of force-expansion characteristics in a newly designed orthodontic expansion screw compared to conventional screws

Directory of Open Access Journals (Sweden)

Oshagh Morteza

2009-01-01

Full Text Available Objective : Expansion screws like Hyrax, Haas and other types, produce heavy interrupted forces which are unfavorable for dental movement and could be harmful to the tooth and periodontium. The other disadvantage of these screws is the need for patient cooperation for their regular activation. The purpose of this study was to design a screw and compare its force- expansion curve with other types. Materials and Methods : A new screw was designed and fabricated in the same dimension, with conventional types, with the ability of 8 mm expansion (Free wire length: 12 mm, initial compression: 4.5 mm, spring wire diameter: 0.4 mm, spring diameter: 3 mm, number of the coils: n0 ine, material: s0 tainless steel. In this in vitro study, the new screw was placed in an acrylic orthodontic appliance, and after mounting on a stone cast, the force-expansion curve was evaluated by a compression test machine and compared to other screws. Results : Force-expansion curve of designed screw had a flatter inclination compared to other screws. Generally it produced a light continuous force (two to 3.5 pounds for every 4 mm of expansion. Conclusion : In comparison with heavy and interrupted forces of other screws, the newly designed screw created light and continuous forces.

Diurnal productivity and apparent 14C-calcification in the staghorn coral, Acropora acuminata

International Nuclear Information System (INIS)

Barnes, D.J.; Crossland, C.J.

1978-01-01

The rate of 14 C-fixation by Acropora acuminata tissues showed a marked increase after dawn. However, maximum 14 C-fixation was not achieved until early afternoon. The apparent 14 C-incorporation rate into the skeleton of whole branches reached a peak around noon. However, the major period of 14 C-deposition occurred from noon to mid-afternoon. The broad peak of 14 C-incorporation into skeleton of whole branches reflects two rate maxima; a late-morning maximum of zooxanthellae-free terminal calices, probably related to translocation of fixed carbon from basal tissues; and an early afternoon maximum for the zooxanthellae-containing basal areas of branches. (author)

With respect to coefficient of linear thermal expansion, bacterial vegetative cells and spores resemble plastics and metals, respectively.

Science.gov (United States)

Nakanishi, Koichi; Kogure, Akinori; Fujii, Takenao; Kokawa, Ryohei; Deuchi, Keiji; Kuwana, Ritsuko; Takamatsu, Hiromu

2013-10-09

If a fixed stress is applied to the three-dimensional z-axis of a solid material, followed by heating, the amount of thermal expansion increases according to a fixed coefficient of thermal expansion. When expansion is plotted against temperature, the transition temperature at which the physical properties of the material change is at the apex of the curve. The composition of a microbial cell depends on the species and condition of the cell; consequently, the rate of thermal expansion and the transition temperature also depend on the species and condition of the cell. We have developed a method for measuring the coefficient of thermal expansion and the transition temperature of cells using a nano thermal analysis system in order to study the physical nature of the cells. The tendency was seen that among vegetative cells, the Gram-negative Escherichia coli and Pseudomonas aeruginosa have higher coefficients of linear expansion and lower transition temperatures than the Gram-positive Staphylococcus aureus and Bacillus subtilis. On the other hand, spores, which have low water content, overall showed lower coefficients of linear expansion and higher transition temperatures than vegetative cells. Comparing these trends to non-microbial materials, vegetative cells showed phenomenon similar to plastics and spores showed behaviour similar to metals with regards to the coefficient of liner thermal expansion. We show that vegetative cells occur phenomenon of similar to plastics and spores to metals with regard to the coefficient of liner thermal expansion. Cells may be characterized by the coefficient of linear expansion as a physical index; the coefficient of linear expansion may also characterize cells structurally since it relates to volumetric changes, surface area changes, the degree of expansion of water contained within the cell, and the intensity of the internal stress on the cellular membrane. The coefficient of linear expansion holds promise as a new index for

Financing electricity expansion

International Nuclear Information System (INIS)

Hyman, L.S.

1994-01-01

Expansion of electricity supply is associated with economic development. The installation and enlargement of power systems in developing countries entails a huge financial burden, however. Energy consumers in such countries must pay not only for supplies but for the cost of raising the capital for expansion on the international markets. Estimates are presented for the capital expenditure for electricity supply over the period 1990 to 2020 for the major world regions, using approximations for the cost of plant and capital and for the returns earned. These data lead to the conclusion that the five regions with the lowest per capita incomes are those which will need the major part of the capital expenditure and the highest percentage of external finance. (6 tables) (UK)

Apparent Coefficient of Friction of Wheat on Denim.

Science.gov (United States)

Schwab, Charles V

2017-07-31

Calculation of the extraction force for a grain entrapment victim requires a coefficient of friction between the grain and the surface of the victim. Because denim is a common fabric for the work clothes that cover entrapment victims, the coefficient of friction between grain and denim becomes necessary. The purpose of this research was to calculate the apparent coefficient of friction of wheat on denim fabric using a proven procedure. The expectation is to improve the current understanding of conditions that influence extraction forces for victims buried in wheat. The apparent coefficient of friction of wheat on denim fabric was calculated to be 0.167 with a standard deviation of ±0.013. The wheat had a moisture content of 10.7% (w.b.) and bulk density of 778.5 kg m-3. The apparent coefficient of friction of wheat on denim was not significantly affected by pull speeds of 0.004, 0.008, and 0.021 mm s-1 nor normal grain pressures of 3.2, 4.8, 6.3, 7.9, and 11.1 kPa. This is a beginning of understanding the conditions that influence the extraction forces for grain entrapment victims. Copyright© by the American Society of Agricultural Engineers.

Preparation of Shrinkage Compensating Concrete with HCSA Expansive Agent

Science.gov (United States)

Li, Changcheng; Jia, Fujia

2017-10-01

Shrinkage compensating concrete (SCC) has become one of the best effective methods of preventing and reducing concrete cracking. SCC is prepared by HCSA high performance expansive agent for concrete which restrained expansion rate is optimized by 0.057%. Slump, compressive strength, restrained expansion rate and cracking resistance test were carried out on SCC. The results show that the initial slump of fresh SCC was about 220mm-230mm, while slump after 2 hours was 180mm-200mm. The restrained expansion rate of SCC increased with the mixing amount of expansive agent. After cured in water for 14 days, the restrained expansion rate of C35 and C40 SCC were 0.020%-0.032%. With the dosage of expansive agent increasing, restrained expansion rate of SCC increased, maximum compressive stress and cracking stress improved, cracking temperature fell, thus cracking resistance got effectively improvement.

Use of expansion joints in power stations

International Nuclear Information System (INIS)

Birker; Rommerswinkel.

1976-01-01

The paper discusses the mode of action of different systems of expansion joints. Special regard is given to the problems of expansion of pipelines of high rated diameter as employed in today's large power plant turbines. Due to the limited space available, the important role of the spring rate of the bellows for the reaction forces and moments acting on the connection points is pointed out. Apart from this details are given on the fabrication and materials selection of expansion joint bellows, and problems are discussed which arise in connection with the mechanical or hydraulic deformation of bellows with one or more walls. The non-destructive methods now in use for the testing of expansion pipe joints are mentioned along with experiments to test their behaviour under changing loads. The paper concludes on some remarks concerning proper transport, storage and installation of expansion pipe joints. (orig./AK) [de

Apparent resistivity for transient electromagnetic induction logging and its correction in radial layer identification

Science.gov (United States)

Meng, Qingxin; Hu, Xiangyun; Pan, Heping; Xi, Yufei

2018-04-01

We propose an algorithm for calculating all-time apparent resistivity from transient electromagnetic induction logging. The algorithm is based on the whole-space transient electric field expression of the uniform model and Halley's optimisation. In trial calculations for uniform models, the all-time algorithm is shown to have high accuracy. We use the finite-difference time-domain method to simulate the transient electromagnetic field in radial two-layer models without wall rock and convert the simulation results to apparent resistivity using the all-time algorithm. The time-varying apparent resistivity reflects the radially layered geoelectrical structure of the models and the apparent resistivity of the earliest time channel follows the true resistivity of the inner layer; however, the apparent resistivity at larger times reflects the comprehensive electrical characteristics of the inner and outer layers. To accurately identify the outer layer resistivity based on the series relationship model of the layered resistance, the apparent resistivity and diffusion depth of the different time channels are approximately replaced by related model parameters; that is, we propose an apparent resistivity correction algorithm. By correcting the time-varying apparent resistivity of radial two-layer models, we show that the correction results reflect the radially layered electrical structure and the corrected resistivities of the larger time channels follow the outer layer resistivity. The transient electromagnetic fields of radially layered models with wall rock are simulated to obtain the 2D time-varying profiles of the apparent resistivity and corrections. The results suggest that the time-varying apparent resistivity and correction results reflect the vertical and radial geoelectrical structures. For models with small wall-rock effect, the correction removes the effect of the low-resistance inner layer on the apparent resistivity of the larger time channels.

Expansion of the agricultural frontier on riparian vegetation of Santa Cruz River, Cuba

Directory of Open Access Journals (Sweden)

Felipe Carricarte Rodríguez

2016-12-01

Full Text Available The work was developed in the Los Amaros, the Santa Cruz river, Artemisa, Cuba. The objective was to evaluate how it influences the expansion of the agricultural frontier on riparian vegetation where the semi-deciduous mesophytic forest (BsdMe predominates. A floristic characterization was performed, identifying the effects of disturbances on the structure and composition of these forests and their relation to human disturbance. A semi-structured interview was applied to all landowners in the study area. Species richness, dominance, basal area, total number of individuals, width of the strip covered by trees and shrubs, and area without vegetation on both banks of the river, respectively were considered as variables. There are differences in the structure and patterns of diversity of the studied forest, as a result of disturbances, with the consequent reduction of species; also anthropogenic disturbances, are the main factors that explain changes in the structure of these forests. They are identified as major species: Cupania macrophylla A. Rich., Roystonea regia HBK O. F. Cook., Guarea guidonia L. Sleumer and Trichilia hirta  L. It is proposed to deepen the effect of the expansion of agriculture into other sectors of the river in interaction with local communities.

THE EXPANSION OF THE RITZ-CARLTON® ON FOREIGN MARKETS

Directory of Open Access Journals (Sweden)

Mihai-Răzvan DOBAI

2016-12-01

Full Text Available The spreading of globalization drives the companies’ pursuit to expand on foreign markets for various reasons. In this paper it will be analysed the expansion on non-US markets of the Ritz-Carlton®, a hotel company with tradition, being known for its services quality. The analysis takes into consideration the opening year of the hotels in the Latin American, European, Middle Eastern, Central and South Asian and AsiaPacific market, trying to correlate the expansion on certain areas and locations with the American foreign policy regarding those regions, one of the essential factors being the improvement and development of economic ties which led to an interdependence between the main actors of the current international affairs arena. Under these circumstances, there were created favourable environments for the hotel to expand on foreign markets. Last but not least, by serving international business people conducting their affairs worldwide and contributing in tightening the economic relations among countries, such a hotel chain is indirectly part of the economic and soft power of a country.

Chromatic Derivatives, Chromatic Expansions and Associated Spaces

OpenAIRE

Ignjatovic, Aleksandar

2009-01-01

This paper presents the basic properties of chromatic derivatives and chromatic expansions and provides an appropriate motivation for introducing these notions. Chromatic derivatives are special, numerically robust linear differential operators which correspond to certain families of orthogonal polynomials. Chromatic expansions are series of the corresponding special functions, which possess the best features of both the Taylor and the Shannon expansions. This makes chromatic derivatives and ...

Warp drive with zero expansion

Energy Technology Data Exchange (ETDEWEB)

Natario, Jose [Department of Mathematics, Instituto Superior Tecnico (Portugal)

2002-03-21

It is commonly believed that Alcubierre's warp drive works by contracting space in front of the warp bubble and expanding the space behind it. We show that this contraction/expansion is but a marginal consequence of the choice made by Alcubierre and explicitly construct a similar spacetime where no contraction/expansion occurs. Global and optical properties of warp-drive spacetimes are also discussed.

Nurse prescribing as an aspect of future role expansion: the views of Irish clinical nurse specialists.

Science.gov (United States)

Lockwood, Emily B; Fealy, Gerard M

2008-10-01

Nurses and midwives are expanding the scope of their professional practice, assuming additional responsibilities including the management and prescribing of medications. The aim of the study was to discover the attitudes of clinical nurse specialists (CNSs) in Ireland to nurse prescribing and to examine perceived barriers to engaging in this aspect of future role expansion. The expansion of the nursing role in relation to nurse prescribing is an ongoing process and is subject to incremental iterations of legislation and professional policy. Nurse prescribing as an expanded role function has become a reality in many countries. Ireland has addressed the matter in a formal and systematic way through legislation. A questionnaire was administered to a sample of 283 CNSs practising in a variety of care settings in Ireland. Attitudes were measured using Likert-type attitudinal scales, designed specifically for the study. Findings indicate that the majority of clinical nurse specialists were positively disposed toward nurse prescribing as a future role expansion. The fear of litigation was identified as the most significant barrier to nurse prescribing. The majority of respondents equated nurse prescribing with increased autonomy and holistic care. The findings indicate that there is a need for further examination of the educational requirements of the CNS in relation to nurse prescribing. The legislative implications for nurse prescribing and fear of legal consequences need to be considered prior to any implementation of nurse prescribing. While senior clinicians are willing to embrace future role expansion in the area of nurse prescribing, their Nurse Managers should recognize that facilitation of nurse prescribing needs to address the legal and educational requirements for such activity. Failure to address these requirements can represent a barrier to role expansion. This paper offers new understandings on the views of senior clinicians concerning nurse prescribing at a

Estimation of apparent kinetic parameters of polymer pyrolysis with complex thermal degradation behavior

International Nuclear Information System (INIS)

Srimachai, Taranee; Anantawaraskul, Siripon

2010-01-01

Full text: Thermal degradation behavior during polymer pyrolysis can typically be described using three apparent kinetic parameters (i.e., pre-exponential factor, activation energy, and reaction order). Several efficient techniques have been developed to estimate these apparent kinetic parameters for simple thermal degradation behavior (i.e., single apparent pyrolysis reaction). Unfortunately, these techniques cannot be directly extended to the case of polymer pyrolysis with complex thermal degradation behavior (i.e., multiple concurrent reactions forming single or multiple DTG peaks). In this work, we proposed a deconvolution method to determine the number of apparent reactions and estimate three apparent kinetic parameters and contribution of each reaction for polymer pyrolysis with complex thermal degradation behavior. The proposed technique was validated with the model and experimental pyrolysis data of several polymer blends with known compositions. The results showed that (1) the number of reaction and (2) three apparent kinetic parameters and contribution of each reaction can be estimated reasonably. The simulated DTG curves with estimated parameters also agree well with experimental DTG curves. (author)

Evidence that a Highway Reduces Apparent Survival Rates of Squirrel Gliders

Directory of Open Access Journals (Sweden)

Sarah C. McCall

2010-09-01

Full Text Available Roads and traffic are prominent components of most landscapes throughout the world, and their negative effects on the natural environment can extend for hundreds or thousands of meters beyond the road. These effects include mortality of wildlife due to collisions with vehicles, pollution of soil and air, modification of wildlife behavior in response to noise, creation of barriers to wildlife movement, and establishment of dispersal conduits for some plant and animal species. In southeast Australia, much of the remaining habitat for the squirrel glider, Petaurus norfolcensis, is located in narrow strips of Eucalyptus woodland that is adjacent to roads and streams, as well as in small patches of woodland vegetation that is farther from roads. We evaluated the effect of traffic volume on squirrel gliders by estimating apparent annual survival rates of adults along the Hume Freeway and nearby low-traffic-volume roads. We surveyed populations of squirrel gliders by trapping them over 2.5 years, and combined these data with prior information on apparent survival rates in populations located away from freeways to model the ratio of apparent annual survival rates in both site types. The apparent annual survival rate of adult squirrel gliders living along the Hume Freeway was estimated to be approximately 60% lower than for squirrel gliders living near local roads. The cause of the reduced apparent survival rate may be due to higher rates of mortality and/or higher emigration rates adjacent to the Hume Freeway compared with populations near smaller country roads. Management options for population persistence will be influenced by which of these factors is the primary cause of a reduced apparent survival rate.

Apparent nutrient digestibility and performance of Heterobranchus ...

African Journals Online (AJOL)

Apparent digestibility coefficients (ADCs) of nutrients is a useful tool for fish diet formulation, which gives the right estimation of growth, thereby reducing waste products. The ADCs of crude protein, energy and dry matter of processed earthworm, Libyodrilus violaceus meal by Heterobranchus longifilis fingerlings ...

Polar cap contraction and expansion during a period of substorms

Science.gov (United States)

Aikio, Anita; Pitkänen, Timo; Honkonen, Ilja; Palmroth, Minna; Amm, Olaf

We have studied the variations in the polar cap area and related parameters during a period of four substorms on February 18, 2004, following an extended quiet period. The measurements were obtained by the EISCAT incoherent scatter radars, MIRACLE magnetometers, Geotail and solar wind satellites. In addition, the event is modeled by the GUMICS-4 MHD simulation. By using the measured and modeled data, the dayside and nightside reconnection voltages are calculated. The results show a good general agreement in the polar cap boundary (PCB) location as estimated by the EISCAT radars and the GUMICS simulation. Deviations are found, too, like shorter durations of expansion phases in the simulation. Geotail measurements of the inclination angle of the magnetic field in the tail (Xgsm= -22 Re) agree with the PCB latitude variations measured by EISCAT at a different MLT. We conclude that a large polar cap corresponds to a stretched tail configuration in the near-Earth tail and a small polar cap to a more dipolar configuration. The substorm onsets took place during southward IMF. A specific feature is that the substorm expansion phases were not associated with significant contractions of the polar cap. Even though nightside reconnection voltages started to increase during expansion phases, maximum closure of open flux took place in the recovery phases. We shortly discuss implications of the observation to the definition of the recovery phase.

Blood pressure and pulse rate of apparently healthy adults on land ...

African Journals Online (AJOL)

Blood pressure and pulse rate of apparently healthy adults on land and in water: A comparative study. AI Bello, BOA Adegoke, OA Abass, O Addo. Abstract. Objective: The study compared cardiovascular parameters of apparently healthy adults in erect standing posture on land and whilst immersed in water at rest. Methods: ...

The δ expansion for stochastic quantization

International Nuclear Information System (INIS)

Bender, C.M.; Cooper, F.; Milton, K.A.; Department of Physics, Brown University, Providence, Rhode Island 02912; Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexic o 87545; Department of Physics, The Ohio State University, Columbus, Ohio 43210; Department of Physics and Astronomy, University of Oklahoma, Norman, Oklaho ma 73019)

1989-01-01

Using a recently proposed perturbation expansion called the δ expansion, we show how to solve the Langevin equation associated with a gphi 4 field theory. We illustrate the technique in zero- and one-dimensional space-time, and then generalize this approach to d dimensions

Considering FACTS in Optimal Transmission Expansion Planning

Directory of Open Access Journals (Sweden)

K. Soleimani

2017-10-01

Full Text Available The expansion of power transmission systems is an important part of the expansion of power systems that requires enormous investment costs. Since the construction of new transmission lines is very expensive, it is necessary to choose the most efficient expansion plan that ensures system security with a minimal number of new lines. In this paper, the role of Flexible AC Transmission System (FACTS devices in the effective operation and expansion planning of transmission systems is examined. Effort was taken to implement a method based on sensitivity analysis to select the optimal number and location of FACTS devices, lines and other elements of the transmission system. Using this method, the transmission expansion plan for a 9 and a 39 bus power system was performed with and without the presence of FACTS with the use of DPL environment in Digsilent software 15.1. Results show that the use of these devices reduces the need for new transmission lines and minimizes the investment cost.

Urban expansion dynamics and natural habitat loss in China: a multiscale landscape perspective.

Science.gov (United States)

He, Chunyang; Liu, Zhifeng; Tian, Jie; Ma, Qun

2014-09-01

China's extensive urbanization has resulted in a massive loss of natural habitat, which is threatening the nation's biodiversity and socioeconomic sustainability. A timely and accurate understanding of natural habitat loss caused by urban expansion will allow more informed and effective measures to be taken for the conservation of biodiversity. However, the impact of urban expansion on natural habitats is not well-understood, primarily due to the lack of accurate spatial information regarding urban expansion across China. In this study, we proposed an approach that can be used to accurately summarize the dynamics of urban expansion in China over two recent decades (1992-2012), by integrating data on nighttime light levels, a vegetation index, and land surface temperature. The natural habitat loss during the time period was evaluated at the national, ecoregional, and local scales. The results revealed that China had experienced extremely rapid urban growth from 1992 to 2012 with an average annual growth rate of 8.74%, in contrast with the global average of 3.20%. The massive urban expansion has resulted in significant natural habitat loss in some areas in China. Special attention needs to be paid to the Pearl River Delta, where 25.79% or 1518 km(2) of the natural habitat and 41.99% or 760 km(2) of the local wetlands were lost during 1992-2012. This raises serious concerns about species viability and biodiversity. Effective policies and regulations must be implemented and enforced to sustain regional and national development in the context of rapid urbanization. © 2014 John Wiley & Sons Ltd.

Simulation program for multiple expansion Stirling machines

International Nuclear Information System (INIS)

Walker, G.; Weiss, M.; Fauvel, R.; Reader, G.; Bingham, E.R.

1992-01-01

Multiple expansion Stirling machines have been a topic of interest at the University of Calgary for some years. Recently a second-order computer simulation program with integral graphics package for Stirling cryocoolers with up to four stages of expansion were developed and made available to the Stirling community. Adaptation of the program to multiple expansion Stirling power systems is anticipated. This paper briefly introduces the program and presents a specimen result

ASSESSING THE IMPACT OF THE HIGHWAY 25 EXPANSION PROJECT ON AIR QUALITY IN MONTREAL USING GIS

Directory of Open Access Journals (Sweden)

Mioara CHIABURU

2010-06-01

Full Text Available Assessing the impact of the highway 25 expansion project on air quality in montreal using gis. The aim of the paper is to assess local air pollution implications of the Highway 25 expansion project from Montreal. The basic concept of the roadway air dispersion model consists in calculating air pollutant levels in the vicinity of a highway by considering it as a line source. To fulfill this assessment, GIS software was used in order to determine pollutant distribution around the study area based on data collected by existing air monitoring stations located in the City of Montreal. GIS interpolation methods, notably Kriging and Inverse Distance Weighted (IDW, was used to generate maps of pollutant concentrations across the study area. From the results, recommendations will be made in regards to the project and appropriate mitigatory alternatives suggested.

Impacts of climate change on range expansion by the mountain pine beetle

Energy Technology Data Exchange (ETDEWEB)

Carroll, A.L.; Taylor, S.W. [Canadian Forest Service, Victoria, BC (Canada). Pacific Forestry Centre; Regniere, J. [Canadian Forest Service, Quebec, PQ (Canada). Laurentian Forestry Centre; Logan, J.A.; Bentz, B.J. [United States Dept. of Agriculture, Logan, UT (United States). Logan Forestry Sciences Laboratory; Powell, J.A. [Utah State Univ., Logan, UT (United States). Dept. of Mathematics and Statistics

2006-07-01

The elevational and latitudinal range of mountain pine beetle (MPB) has been limited by climatic conditions that are currently unfavorable for brood development. This study examined the impact of climatic conditions on the establishment and persistence of MPB using a spatially explicit, climate-driven simulation tool. Historic weather records were also used to create maps of past habitats for MPB in British Columbia. Map overlays were then created to determine if MPB has expanded its range due to changes in the province's climate. The distribution of climatically suitable habitats was examined in 10-year increments. Results of the study showed an increase in benign habitats. MPB populations have expanded into new areas as a result of changes in climate. Additional range expansion for MPB was then assessed using a global circulation model along with a conservative forcing scenario that forecast a doubling of carbon dioxide (CO{sub 2}) by 2050. Weather conditions were then combined with a climatic suitability model in order to examine areas of climatically suitable habitats. It was concluded that continued eastward expansion by MPB is probable. 44 refs., 4 tabs., 7 figs.

Geographic Expansion of Lyme Disease in the Southeastern United States, 2000-2014.

Science.gov (United States)

Lantos, Paul M; Nigrovic, Lise E; Auwaerter, Paul G; Fowler, Vance G; Ruffin, Felicia; Brinkerhoff, R Jory; Reber, Jodi; Williams, Carl; Broyhill, James; Pan, William K; Gaines, David N

2015-12-01

Background.  The majority of Lyme disease cases in the United States are acquired on the east coast between northern Virginia and New England. In recent years the geographic extent of Lyme disease has been expanding, raising the prospect of Lyme disease becoming endemic in the southeast. Methods.  We collected confirmed and probable cases of Lyme disease from 2000 through 2014 from the Virginia Department of Health and North Carolina Department of Public Health and entered them in a geographic information system. We performed spatial and spatiotemporal cluster analyses to characterize Lyme disease expansion. Results.  There was a marked increase in Lyme disease cases in Virginia, particularly from 2007 onwards. Northern Virginia experienced intensification and geographic expansion of Lyme disease cases. The most notable area of expansion was to the southwest along the Appalachian Mountains with development of a new disease cluster in the southern Virginia mountain region. Conclusions.  The geographic distribution of Lyme disease cases significantly expanded in Virginia between 2000 and 2014, particularly southward in the Virginia mountain ranges. If these trends continue, North Carolina can expect autochthonous Lyme disease transmission in its mountain region in the coming years.

Global protected area expansion is compromised by projected land-use and parochialism

NARCIS (Netherlands)

Pouzols, F.M.; Toivonen, T.; Di Minin, E.; Kukkala, A.; Kullberg, P.; Kuustera, J.; Lehtomaki, J.; Tenkanen, H.; Verburg, P.H.; Moilanan, A.

2014-01-01

Protected areas are one of the main tools for halting the continuing global biodiversity crisis caused by habitat loss, fragmentation and other anthropogenic pressures. According to the Aichi Biodiversity Target 11 adopted by the Convention on Biological Diversity, the protected area network should

Controlling Thermal Expansion: A Metal-Organic Frameworks Route.

Science.gov (United States)

Balestra, Salvador R G; Bueno-Perez, Rocio; Hamad, Said; Dubbeldam, David; Ruiz-Salvador, A Rabdel; Calero, Sofia

2016-11-22

Controlling thermal expansion is an important, not yet resolved, and challenging problem in materials research. A conceptual design is introduced here, for the first time, for the use of metal-organic frameworks (MOFs) as platforms for controlling thermal expansion devices that can operate in the negative, zero, and positive expansion regimes. A detailed computer simulation study, based on molecular dynamics, is presented to support the targeted application. MOF-5 has been selected as model material, along with three molecules of similar size and known differences in terms of the nature of host-guest interactions. It has been shown that adsorbate molecules can control, in a colligative way, the thermal expansion of the solid, so that changing the adsorbate molecules induces the solid to display positive, zero, or negative thermal expansion. We analyze in depth the distortion mechanisms, beyond the ligand metal junction, to cover the ligand distortions, and the energetic and entropic effect on the thermo-structural behavior. We provide an unprecedented atomistic insight on the effect of adsorbates on the thermal expansion of MOFs as a basic tool toward controlling the thermal expansion.

The Economic Impact of Medicaid Expansion on Pennsylvania.

Science.gov (United States)

Price, Carter C; Donohue, Julie M; Saltzman, Evan; Woods, Dulani; Eibner, Christine

2013-01-01

The Affordable Care Act is a substantial reform of the U.S. health care insurance system. Using the RAND COMPARE model, researchers assessed the act's potential economic effects on Pennsylvania, factoring in an optional expansion of Medicaid, and found the state would enjoy significant net benefits. With or without the expansion of Medicaid, the act will increase insurance coverage to hundreds of thousands of Pennsylvanians, but the COMPARE model estimates that the expansion of Medicaid eligibility would cover an additional 350,000 people and bring more than $2 billion in federal spending into the state annually than if the state did not expand. Should the state expand Medicaid, the additional spending will add more than $3 billion a year to the state's GDP and support 35,000 jobs. But Medicaid expansion is not without cost for the state; the estimated cumulative effect on Pennsylvania's Medicaid spending will be $180 million higher with the expansion than without between 2014 and 2020. Substantial reductions in uncompensated care costs for hospitals are possible even without expansion, but savings to hospitals for uncompensated care funding are even larger with the Medicaid expansion, amounting to $550 million or more each year.

Controlling Thermal Expansion: A Metal–Organic Frameworks Route

Science.gov (United States)

2016-01-01

Controlling thermal expansion is an important, not yet resolved, and challenging problem in materials research. A conceptual design is introduced here, for the first time, for the use of metal–organic frameworks (MOFs) as platforms for controlling thermal expansion devices that can operate in the negative, zero, and positive expansion regimes. A detailed computer simulation study, based on molecular dynamics, is presented to support the targeted application. MOF-5 has been selected as model material, along with three molecules of similar size and known differences in terms of the nature of host–guest interactions. It has been shown that adsorbate molecules can control, in a colligative way, the thermal expansion of the solid, so that changing the adsorbate molecules induces the solid to display positive, zero, or negative thermal expansion. We analyze in depth the distortion mechanisms, beyond the ligand metal junction, to cover the ligand distortions, and the energetic and entropic effect on the thermo-structural behavior. We provide an unprecedented atomistic insight on the effect of adsorbates on the thermal expansion of MOFs as a basic tool toward controlling the thermal expansion. PMID:28190918

Platform Expansion Design as Strategic Choice

DEFF Research Database (Denmark)

Staykova, Kalina S.; Damsgaard, Jan

2016-01-01

In this paper, we address how the strategic choice of platform expansion design impacts the subse-quent platform strategy. We identify two distinct approaches to platform expansion – platform bun-dling and platform constellations, which currently co-exist. The purpose of this paper is to outline...

Thermal expansion behavior in fabricated cellular structures

International Nuclear Information System (INIS)

Oruganti, R.K.; Ghosh, A.K.; Mazumder, J.

2004-01-01

Thermal expansion behavior of cellular structures is of interest in applications where undesirable deformation and failure are caused by thermal expansion mismatch. This report describes the role of processing-induced effects and metallurgical aspects of melt-processed cellular structures, such as a bi-material structure designed to contract on heating, as well as uni-material structures of regular and stochastic topology. This bi-material structure utilized the principle of internal geometric constraints to alter the expansion behavior of the internal ligaments to create overall contraction of the structure. Homogenization design method was used to design the structure, and fabrication was by direct metal deposition by laser melting of powder in another part of a joint effort. The degree of porosity and grain size in the fabricated structure are characterized and related to the laser deposition parameters. The structure was found to contract upon heating over a short range of temperature subsequent to which normal expansion ensued. Also examined in this report are uni-material cellular structures, in which internal constraints arise from residual stress variations caused by the fabrication process, and thereby alter their expansion characteristics. A simple analysis of thermal strain of this material supports the observed thermal expansion behavior

Secret-key expansion from covert communication

Science.gov (United States)

Arrazola, Juan Miguel; Amiri, Ryan

2018-02-01

Covert communication allows the transmission of messages in such a way that it is not possible for adversaries to detect that the communication is occurring. This provides protection in situations where knowledge that two parties are talking to each other may be incriminating to them. In this work, we study how covert communication can be used for a different purpose: secret key expansion. First, we show that any message transmitted in a secure covert protocol is also secret and therefore unknown to an adversary. We then propose a covert communication protocol where the amount of key consumed in the protocol is smaller than the transmitted key, thus leading to secure secret key expansion. We derive precise conditions for secret key expansion to occur, showing that it is possible when there are sufficiently low levels of noise for a given security level. We conclude by examining how secret key expansion from covert communication can be performed in a computational security model.

From greedy to lazy expansions and their driving dynamics

NARCIS (Netherlands)

Dajani, K.; Kraaikamp, C.

2001-01-01

In this paper we study the ergodic properties of non-greedy series expansions to non-integer bases β > 1. It is shown that the so-called 'lazy' expansion is isomorphic to the 'greedy' expansion. Furthermore, a class of expansions to base β > 1, β =2 Z, 'in between' the lazy and the greedy

RTEL1 Inhibits Trinucleotide Repeat Expansions and Fragility

Directory of Open Access Journals (Sweden)

Aisling Frizzell

2014-03-01

Full Text Available Human RTEL1 is an essential, multifunctional helicase that maintains telomeres, regulates homologous recombination, and helps prevent bone marrow failure. Here, we show that RTEL1 also blocks trinucleotide repeat expansions, the causal mutation for 17 neurological diseases. Increased expansion frequencies of (CTG⋅CAG repeats occurred in human cells following knockdown of RTEL1, but not the alternative helicase Fbh1, and purified RTEL1 efficiently unwound triplet repeat hairpins in vitro. The expansion-blocking activity of RTEL1 also required Rad18 and HLTF, homologs of yeast Rad18 and Rad5. These findings are reminiscent of budding yeast Srs2, which inhibits expansions, unwinds hairpins, and prevents triplet-repeat-induced chromosome fragility. Accordingly, we found expansions and fragility were suppressed in yeast srs2 mutants expressing RTEL1, but not Fbh1. We propose that RTEL1 serves as a human analog of Srs2 to inhibit (CTG⋅CAG repeat expansions and fragility, likely by unwinding problematic hairpins.

Thermal expansion studies on Hafnium titanate (HfTiO4)

International Nuclear Information System (INIS)

Panneerselvam, G.; Subramanian, G.G.S.; Antony, M.P.

2006-01-01

The lattice thermal expansion characteristics of hafnium titanate (HfTiO 4 ) have been studied by measuring the lattice parameter as a function of temperature by high temperature X-ray diffraction technique (HT-XRD) in the temperature range 298-1973K. Percentage linear thermal expansion and mean linear thermal expansion coefficients were computed from the lattice parameter data. The thermal expansion of HfTiO 4 is highly anisotropic. The expansivity along 'a' axis is large; as compared to the expansivity along 'b' axis which is negative below 1073 K. The percentage linear thermal expansion in the temperature range 298-1973 K along a, b and c axis are 2.74, 0.901 and 1.49 respectively. Thermal expansion values obtained in the present study are in reasonable agreement with the existing thermal expansion data. (author)

Fuel conversion efficiency improvements in a highly boosted spark-ignition engine with ultra-expansion cycle

International Nuclear Information System (INIS)

Li, Tie; Zheng, Bin; Yin, Tao

2015-01-01

Highlights: • Ultra-expansion cycle SI engine is investigated. • An improvement of 9–26% in BSFC at most frequently operated conditions is obtained. • At high and medium loads, BSFC improvement is attributed to the increased combustion efficiency and reduced exhaust energy. • At low loads, reduction in pumping loss and exhaust energy is the primary contributors to BSFC improvement. • Technical challenge in practical application of this type of engine is discussed. - Abstract: A four-cylinder, intake boosted, port fuel injection (PFI), spark-ignition (SI) engine is modified to a three-cylinder engine with the outer two cylinders working in the conventional four stroke cycle and with the inner cylinder working only with the expansion and exhausting strokes. After calibration and validation of the engine cycle simulation models using the experimental data in the original engine, the performance of the three-cylinder engine with the ultra-expansion cycle is numerically studied. Compared to the original engine, the fuel consumptions under the most-frequently operated conditions are improved by 9–26% and the low fuel consumption area on the operating map are drastically enlarged for the ultra-expansion cycle engine with the proper design. Nonetheless, a higher intake boosting is needed for the ultra-expansion cycle engine to circumvent the significant drop in the wide-open-throttle (WOT) performance, and compression ratio of the combustion cylinder must be reduced to avoid knocking combustion. Despite of the reduced compression ratio, however, the total expansion ratio is increased to 13.8 with the extra expansion of the working gas in the inner cylinder. Compared to the conventional engine, the theoretical thermal efficiency is therefore increased by up to above 4.0% with the ultra-expansion cycle over the most load range. The energy balance analysis shows that the increased combustion efficiency, reduced exhaust energy and the extra expansion work in the

Hypersonic expansion of the Fokker--Planck equation

International Nuclear Information System (INIS)

Fernandez-Feria, R.

1989-01-01

A systematic study of the hypersonic limit of a heavy species diluted in a much lighter gas is made via the Fokker--Planck equation governing its velocity distribution function. In particular, two different hypersonic expansions of the Fokker--Planck equation are considered, differing from each other in the momentum equation of the heavy gas used as the basis of the expansion: in the first of them, the pressure tensor is neglected in that equation while, in the second expansion, the pressure tensor term is retained. The expansions are valid when the light gas Mach number is O(1) or larger and the difference between the mean velocities of light and heavy components is small compared to the light gas thermal speed. They can be applied away from regions where the spatial gradient of the distribution function is very large, but it is not restricted with respect to the temporal derivative of the distribution function. The hydrodynamic equations corresponding to the lowest order of both expansions constitute two different hypersonic closures of the moment equations. For the subsequent orders in the expansions, closed sets of moment equations (hydrodynamic equations) are given. Special emphasis is made on the order of magnitude of the errors of the lowest-order hydrodynamic quantities. It is shown that if the heat flux vanishes initially, these errors are smaller than one might have expected from the ordinary scaling of the hypersonic closure. Also it is found that the normal solution of both expansions is a Gaussian distribution at the lowest order

Oral temperature and cardiovascular responses of apparently ...

African Journals Online (AJOL)

Oral temperature and cardiovascular responses of apparently healthy subjects to passive and active warm-up. BOA Adegoke, OO Ogwumike, FA Maruf. Abstract. This study investigated and compared the effects of active and passive warm-up on oral temperature and cardiovascular parameters of forty (20 males and 20 ...

14 CFR 23.969 - Fuel tank expansion space.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel tank expansion space. 23.969 Section 23.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT....969 Fuel tank expansion space. Each fuel tank must have an expansion space of not less than two...

Research progress on expansive soil cracks under changing environment.

Science.gov (United States)

Shi, Bei-xiao; Zheng, Cheng-feng; Wu, Jin-kun

2014-01-01

Engineering problems shunned previously rise to the surface gradually with the activities of reforming the natural world in depth, the problem of expansive soil crack under the changing environment becoming a control factor of expansive soil slope stability. The problem of expansive soil crack has gradually become a research hotspot, elaborates the occurrence and development of cracks from the basic properties of expansive soil, and points out the role of controlling the crack of expansive soil strength. We summarize the existing research methods and results of expansive soil crack characteristics. Improving crack measurement and calculation method and researching the crack depth measurement, statistical analysis method, crack depth and surface feature relationship will be the future direction.

Identification of invasive and expansive plant species based on airborne hyperspectral and ALS data

Science.gov (United States)

Szporak-Wasilewska, Sylwia; Kuc, Gabriela; Jóźwiak, Jacek; Demarchi, Luca; Chormański, Jarosław; Marcinkowska-Ochtyra, Adriana; Ochtyra, Adrian; Jarocińska, Anna; Sabat, Anita; Zagajewski, Bogdan; Tokarska-Guzik, Barbara; Bzdęga, Katarzyna; Pasierbiński, Andrzej; Fojcik, Barbara; Jędrzejczyk-Korycińska, Monika; Kopeć, Dominik; Wylazłowska, Justyna; Woziwoda, Beata; Michalska-Hejduk, Dorota; Halladin-Dąbrowska, Anna

2017-04-01

The aim of Natura 2000 network is to ensure the long term survival of most valuable and threatened species and habitats in Europe. The encroachment of invasive alien and expansive native plant species is among the most essential threat that can cause significant damage to protected habitats and their biodiversity. The phenomenon requires comprehensive and efficient repeatable solutions that can be applied to various areas in order to assess the impact on habitats. The aim of this study is to investigate of the issue of invasive and expansive plant species as they affect protected areas at a larger scale of Natura 2000 network in Poland. In order to determine the scale of the problem we have been developing methods of identification of invasive and expansive species and then detecting their occurrence and mapping their distribution in selected protected areas within Natura 2000 network using airborne hyperspectral and airborne laser scanning data. The aerial platform used consists of hyperspectral HySpex scanner (451 bands in VNIR and SWIR), Airborne Laser Scanner (FWF) Riegl Lite Mapper and RGB camera. It allowed to obtain simultaneous 1 meter resolution hyperspectral image, 0.1 m resolution orthophotomaps and point cloud data acquired with 7 points/m2. Airborne images were acquired three times per year during growing season to account for plant seasonal change (in May/June, July/August and September/October 2016). The hyperspectral images were radiometrically, geometrically and atmospherically corrected. Atmospheric correction was performed and validated using ASD FieldSpec 4 measurements. ALS point cloud data were used to generate several different topographic, vegetation and intensity products with 1 m spatial resolution. Acquired data (both hyperspectral and ALS) were used to test different classification methods including Mixture Tuned Matched Filtering (MTMF), Spectral Angle Mapper (SAM), Random Forest (RF), Support Vector Machines (SVM), among others

Apparent molar volumes and compressibilities of electrolytes and ions in γ-butyrolactone

International Nuclear Information System (INIS)

Krakowiak, Joanna; Wawer, Jarosław; Farmas, Aleksander

2012-01-01

Highlights: ► Density and speed of sound for salts solutions in γ-butyrolactone were measured. ► The apparent molar volumes and compressibilities have been determined. ► The limiting molar quantities are split into independent ionic contributions. ► These data are used to describe ion–solvent interactions. - Abstract: The densities of tetraphenylphosphonium bromide, sodium tetraphenylborate, lithium perchlorate, sodium perchlorate and lithium bromide in γ-butyrolactone at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and speed of sound at 298.15 K have been measured. From these data apparent molar volumes V Φ at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and the apparent molar isentropic compressibility K S,Φ , at T = 298.15 K of the salts have been determined. The apparent molar volumes and the apparent molar isentropic compressibilities were fitted to the Redlich, Rosenfeld and Mayer equation as well as to the Pitzer and Masson equations yielding infinite dilution data. The obtained limiting values have been used to estimate the ionic data of the standard partial molar volume and the standard partial isentropic compressibility in γ-butyrolactone solutions.

Numerical stress analysis of the iris tissue induced by pupil expansion: Comparison of commercial devices

Science.gov (United States)

Wang, Xiaofei; Perera, Shamira A.; Girard, Michaël J. A.

2018-01-01

Purpose (1) To use finite element (FE) modelling to estimate local iris stresses (i.e. internal forces) as a result of mechanical pupil expansion; and to (2) compare such stresses as generated from several commercially available expanders (Iris hooks, APX dilator and Malyugin ring) to determine which design and deployment method are most likely to cause iris damage. Methods We used a biofidelic 3-part iris FE model that consisted of the stroma, sphincter and dilator muscles. Our FE model simulated expansion of the pupil from 3 mm to a maximum of 6 mm using the aforementioned pupil expanders, with uniform circular expansion used for baseline comparison. FE-derived stresses, resultant forces and area of final pupil opening were compared across devices for analysis. Results Our FE models demonstrated that the APX dilator generated the highest stresses on the sphincter muscles, (max: 6.446 MPa; average: 5.112 MPa), followed by the iris hooks (max: 5.680 MPa; average: 5.219 MPa), and the Malyugin ring (max: 2.144 MPa; average: 1.575 MPa). Uniform expansion generated the lowest stresses (max: 0.435MPa; average: 0.377 MPa). For pupil expansion, the APX dilator required the highest force (41.22 mN), followed by iris hooks (40.82 mN) and the Malyugin ring (18.56 mN). Conclusion Our study predicted that current pupil expanders exert significantly higher amount of stresses and forces than required during pupil expansion. Our work may serve as a guide for the development and design of next-generation pupil expanders. PMID:29538452

Exploring the institutional perspective on international business expansion: Towards a more detailed conceptual framework

Directory of Open Access Journals (Sweden)

Richard Lynch

2016-05-01

Full Text Available While the general principles of the Institutional Perspective have been widely accepted, there has been only limited consideration to the present time of their in-depth application to the strategies of individual firms engaged in international business. The paper argues that companies engaged in such activities will find that there is a significant gap in precisely what aspects of the formal and informal institutional perspectives need to be identified and assessed for international expansion. The purpose of this paper is to develop a theoretical paradigm that allows organizations not only to compare different countries with regard to their potential for international business expansion from the perspective of Institutional Theory but also drawing on theories of International Business Strategy where relevant. The theoretical framework assumes that such organizations are engaged in analyzing the institutional arrangements and resources of their home and possible host countries. The paper then develops a conceptual framework that identifies five major components, namely people, power, performance, pathways to international expansion, and productivity, the latter being defined in terms of knowledge and innovation. It explores each of these areas in more depth with the aim of adding a more detailed structure to elements of Institutional Theory relevant to international business expansion.

Zirconium titanate: stability and thermal expansion; Titanato de circonio: estabilidad termodinamica y expansion termica

Energy Technology Data Exchange (ETDEWEB)

Lopez-Lopez, E.; Moreno, R.; Baudin, C.

2011-07-01

Zirconium titanate is a well known compound in the field of electro ceramics, although it has also been used in catalyst and sensors applications. The crystallographic thermal expansion anisotropy of this compound makes it a potential candidate as constituent of structural components. In general, to assure the structural integrity and microstructural homogeneity of a ceramic piece, relatively low cooling rates from the fabrication temperature are required. This requirement is essential for zirconium titanate because thermal expansion as well as phase distribution is affected by small variations in the composition and cooling rate. This work reviews the available data on the phase equilibrium relationships in the systems ZrO{sub 2}-TiO{sub 2} and ZrO{sub 2}-TiO{sub 2}-Y{sub 2}O{sub 3}. The main discrepancies as well as the possible origins of them are discussed. Additionally, the crystallographic thermal expansion data in the current literature are reviewed. (Author) 56 refs.

Multi-epoch VLBA Imaging of 20 New TeV Blazars: Apparent Jet Speeds

Science.gov (United States)

Piner, B. Glenn; Edwards, Philip G.

2018-01-01

We present 88 multi-epoch Very Long Baseline Array (VLBA) images (most at an observing frequency of 8 GHz) of 20 TeV blazars, all of the high-frequency-peaked BL Lac (HBL) class, that have not been previously studied at multiple epochs on the parsec scale. From these 20 sources, we analyze the apparent speeds of 43 jet components that are all detected at four or more epochs. As has been found for other TeV HBLs, the apparent speeds of these components are relatively slow. About two-thirds of the components have an apparent speed that is consistent (within 2σ) with no motion, and some of these components may be stationary patterns whose apparent speed does not relate to the underlying bulk flow speed. In addition, a superluminal tail to the apparent speed distribution of the TeV HBLs is detected for the first time, with eight components in seven sources having a 2σ lower limit on the apparent speed exceeding 1c. We combine the data from these 20 sources with an additional 18 sources from the literature to analyze the complete apparent speed distribution of all 38 TeV HBLs that have been studied with very long baseline interferometry at multiple epochs. The highest 2σ apparent speed lower limit considering all sources is 3.6c. This suggests that bulk Lorentz factors of up to about 4, but probably not much higher, exist in the parsec-scale radio-emitting regions of these sources, consistent with estimates obtained in the radio by other means such as brightness temperatures. This can be reconciled with the high Lorentz factors estimated from the high-energy data if the jet has velocity structures consisting of different emission regions with different Lorentz factors. In particular, we analyze the current apparent speed data for the TeV HBLs in the context of a model with a fast central spine and a slower outer layer.

Semiclassical expansions on and near caustics

International Nuclear Information System (INIS)

Meetz, K.

1984-09-01

We show that the standard WKB expansion can be generalized so that it reproduces the behavior of the wave function on and near a caustic in two-dimensional space time. The expansion is related to the unfolding polynomials of the elementary catastrophes occurring in two dimensions: the fold and the cusp catastrophe. The method determines control parameters and transport coefficients in a self-consistent way from differential equations and does not refer to the asymptotic expansion of Feynman path integrals. The lowest order equations are solved explicitly in terms of the multivalued classical action. The result is a generalized semiclassical approximation on and beyond a caustic. (orig.)

Interbasis expansions for isotropic harmonic oscillator

Energy Technology Data Exchange (ETDEWEB)

Dong, Shi-Hai, E-mail: dongsh2@yahoo.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, Mexico D.F. 07738 (Mexico)

2012-03-12

The exact solutions of the isotropic harmonic oscillator are reviewed in Cartesian, cylindrical polar and spherical coordinates. The problem of interbasis expansions of the eigenfunctions is solved completely. The explicit expansion coefficients of the basis for given coordinates in terms of other two coordinates are presented for lower excited states. Such a property is occurred only for those degenerated states for given principal quantum number n. -- Highlights: ► Exact solutions of harmonic oscillator are reviewed in three coordinates. ► Interbasis expansions of the eigenfunctions is solved completely. ► This is occurred only for those degenerated states for given quantum number n.

Cosmic growth history and expansion history

International Nuclear Information System (INIS)

Linder, Eric V.

2005-01-01

The cosmic expansion history tests the dynamics of the global evolution of the universe and its energy density contents, while the cosmic growth history tests the evolution of the inhomogeneous part of the energy density. Precision comparison of the two histories can distinguish the nature of the physics responsible for the accelerating cosmic expansion: an additional smooth component--dark energy--or a modification of the gravitational field equations. With the aid of a new fitting formula for linear perturbation growth accurate to 0.05%-0.2%, we separate out the growth dependence on the expansion history and introduce a new growth index parameter γ that quantifies the gravitational modification

Correlation expansion: a powerful alternative multiple scattering calculation method

International Nuclear Information System (INIS)

Zhao Haifeng; Wu Ziyu; Sebilleau, Didier

2008-01-01

We introduce a powerful alternative expansion method to perform multiple scattering calculations. In contrast to standard MS series expansion, where the scattering contributions are grouped in terms of scattering order and may diverge in the low energy region, this expansion, called correlation expansion, partitions the scattering process into contributions from different small atom groups and converges at all energies. It converges faster than MS series expansion when the latter is convergent. Furthermore, it takes less memory than the full MS method so it can be used in the near edge region without any divergence problem, even for large clusters. The correlation expansion framework we derive here is very general and can serve to calculate all the elements of the scattering path operator matrix. Photoelectron diffraction calculations in a cluster containing 23 atoms are presented to test the method and compare it to full MS and standard MS series expansion

Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

Directory of Open Access Journals (Sweden)

Xingjun Lv

2011-11-01

Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

Science.gov (United States)

Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

2011-01-01

In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Treatment of divergent expansions in scattering theory

International Nuclear Information System (INIS)

Gersten, A.; Malin, S.

1978-01-01

One of the biggest obstacles in applying quantum field theory to realistic scattering problems are the divergencies of pertubation expansions for large coupling constants and the divergencies of partial wave expansions for massless particles exchanges. There exist, however, methods of summation of the divergent expansions which can lead to significant application in physics. In this paper we treat the problem of summing such expansions using three methods: (i) a generalization of the Pade approximation to the multivariable case. The suggested definition is unique and preserves unitarity. (ii) The summation of divergent partial waves for arbitrary spins. (iii) A successful application of a series inversion to the 3 P 1 nucleon-nucleon phase shift up to 200 MeV. (orig./WL) [de

The loop expansion as a divergent-power-series expansion

International Nuclear Information System (INIS)

Murai, N.

1981-01-01

The loop expansion should be divergent, possibly an asymptotic one, in the Euclidean path integral formulation. This consideration is important in applications of the symmetric and mass-independent renormalization. The [1,1] Pade approximant is calculated in a PHI 4 model. Its classical vacua may be not truely stable for nonzero coupling constant. (author)

The heavy quark expansion of QCD

Energy Technology Data Exchange (ETDEWEB)

Falk, A.F. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy

1997-06-01

These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs.

The heavy quark expansion of QCD

International Nuclear Information System (INIS)

Falk, A.F.

1997-01-01

These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs

Thermal expansion of doped lanthanum gallates

Indian Academy of Sciences (India)

Administrator

Since the components are in intimate mechanical contact, any stress generated due to their thermal expansion mis- match during thermal cycling could lead to catastrophic failure of the cell. The functional materials must have similar thermal expansions to avoid mechanical stresses. Hence it is useful to study the thermal ...

Does assimilate supply limit expansion in wheat grown in the field under low phosphorus availability

NARCIS (Netherlands)

Rodriguez, D.; Andrade, F.H.; Goudriaan, J.

2000-01-01

Under conditions of phosphorus deficiency, reductions in plant leaf area have been attributed to both direct effects of phosphorus (P) on the individual leaf expansion rate and a reduced availability of assimilates for leaf growth. Simulation techniques have been used to test the hypothesis of a

Thermal and hygroscopic expansion characteristics of bamboo

OpenAIRE

Huang, Puxi; Chang, Wen-shao; Ansell, Martin P.; Bowen, Chris R.; Chew, John Y. M.; Adamak, Vana i

2017-01-01

The expansion and contraction of bamboo caused by temperature and moisture variations must be evaluated\\ud if bamboo is to be utilised as a building material. However, detailed expansion data, especially data in the ascent and\\ud descent processes of temperature and moisture are unexplored. The aim of this study is to investigate the expansion\\ud characteristics of Phyllostachys edulis (Moso bamboo) in ascent and descent processes of temperature and moisture.\\ud The measurement of linear ther...

Semiclassical expansions for confined N fermion systems

International Nuclear Information System (INIS)

Krivine, H.; Martorell, J.; Casas, M.

1989-01-01

A new derivation of the Wigner Kirkwood expansion for N-fermion systems is presented, showing explicitly the connection to the WKB approximation for a single level. This allows to study separately the two ansatz required to obtain the semiclassical expansions: the asymptotic expansions in powers of ℎ and the smoothing of quantal effects. We discuss the one dimensional and three dimensional, with spherical symmetry, cases. Applications for standard potentials used in nuclear physics are described in detail

Explaining the apparent paradox of persistent selection for early flowering.

Science.gov (United States)

Austen, Emily J; Rowe, Locke; Stinchcombe, John R; Forrest, Jessica R K

2017-08-01

Decades of observation in natural plant populations have revealed pervasive phenotypic selection for early flowering onset. This consistent pattern seems at odds with life-history theory, which predicts stabilizing selection on age and size at reproduction. Why is selection for later flowering rare? Moreover, extensive evidence demonstrates that flowering time can and does evolve. What maintains ongoing directional selection for early flowering? Several non-mutually exclusive processes can help to reconcile the apparent paradox of selection for early flowering. We outline four: selection through other fitness components may counter observed fecundity selection for early flowering; asymmetry in the flowering-time-fitness function may make selection for later flowering hard to detect; flowering time and fitness may be condition-dependent; and selection on flowering duration is largely unaccounted for. In this Viewpoint, we develop these four mechanisms, and highlight areas where further study will improve our understanding of flowering-time evolution. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Mechanism of actuation in conducting polymers: Osmotic expansion

DEFF Research Database (Denmark)

Bay, Lasse; Jacobsen, Torben; West, Keld

2001-01-01

Conducting polymers expand or contract when their redox state is changed. This expansion/contraction effect can be separated in an intrinsic part because of changes of the polymer backbone on reduction/oxidation and a part depending on the surrounding electrolyte phase, because of osmotic expansion...... is compared with measurements on PPy(DBS) films. The experiments show that the expansion decreases as the electrolyte concentration is increased. This means that a considerable part of the total expansion is due to the osmotic effect. The osmotic effect should be taken into account when interpreting...

Thermal expansion of fibre-reinforced composites

International Nuclear Information System (INIS)

Schneider, B.

1991-07-01

The integral thermal expansion and the coefficient of thermal expansion (CTE) of carbon and Kevlar fibre-reinforced composites were measured with high accuracy from 5 K to room temperature. For this, a laser dilatometer and a sophisticated measuring procedure were used. CTE dependence on the orientation angle ω of angle-ply laminates was determined for samples with 5 different fibre alignments (UD 0deg, +/-30deg, +/-45deg, +/-60deg and UD 90deg). A high variability of the CTE with the orientation angle was shown. At angles of approximately +/-30deg even negative CTEs were found. With suitable reinforcing fibres being selected, their absolute values rose up to 30-100% of the positive CTEs of metals. Hence, composites of this type would be suitable as compensating materials in metal constructions where little thermal expansion is desired. To check the lamination theory, theoretical computations of the CTE- ω -dependence were compared with the measured values. An excellent agreement was found. Using the lamination theory, predictions about the expansion behaviour of angle-ply laminates can be made now, if the thermal and mechanical properties of the unidirectional (UD) laminate are known. Furthermore, it is possible to carry out simulation computations aimed at investigating the influence of a single parameter of the UD-laminate (e.g. shear modulus) on the expansion of the angle-ply laminate. (orig.) [de

On equivalence of high temperature series expansion and coupling parameter series expansion in thermodynamic perturbation theory of fluids

International Nuclear Information System (INIS)

Sai Venkata Ramana, A.

2014-01-01

The coupling parameter series expansion and the high temperature series expansion in the thermodynamic perturbation theory of fluids are shown to be equivalent if the interaction potential is pairwise additive. As a consequence, for the class of fluids with the potential having a hardcore repulsion, if the hard-sphere fluid is chosen as reference system, the terms of coupling parameter series expansion for radial distribution function, direct correlation function, and Helmholtz free energy follow a scaling law with temperature. The scaling law is confirmed by application to square-well fluids

Strategic Complexity and Global Expansion

DEFF Research Database (Denmark)

Oladottir, Asta Dis; Hobdari, Bersant; Papanastassiou, Marina

2012-01-01

The purpose of this paper is to analyse the determinants of global expansion strategies of newcomer Multinational Corporations (MNCs) by focusing on Iceland, Israel and Ireland. We argue that newcomer MNCs from small open economies pursue complex global expansion strategies (CGES). We distinguish....... The empirical evidence suggests that newcomer MNCs move away from simplistic dualities in the formulation of their strategic choices towards more complex options as a means of maintaining and enhancing their global competitiveness....

Range expansion of heterogeneous populations.

Science.gov (United States)

Reiter, Matthias; Rulands, Steffen; Frey, Erwin

2014-04-11

Risk spreading in bacterial populations is generally regarded as a strategy to maximize survival. Here, we study its role during range expansion of a genetically diverse population where growth and motility are two alternative traits. We find that during the initial expansion phase fast-growing cells do have a selective advantage. By contrast, asymptotically, generalists balancing motility and reproduction are evolutionarily most successful. These findings are rationalized by a set of coupled Fisher equations complemented by stochastic simulations.

Low Thermal Expansion Glass Ceramics

CERN Document Server

Bach, Hans

2005-01-01

This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

Low thermal expansion glass ceramics

CERN Document Server

1995-01-01

This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

Regulation of gas infrastructure expansion

International Nuclear Information System (INIS)

De Joode, J.

2012-01-01

The topic of this dissertation is the regulation of gas infrastructure expansion in the European Union (EU). While the gas market has been liberalised, the gas infrastructure has largely remained in the regulated domain. However, not necessarily all gas infrastructure facilities - such as gas storage facilities, LNG import terminals and certain gas transmission pipelines - need to be regulated, as there may be scope for competition. In practice, the choice of regulation of gas infrastructure expansion varies among different types of gas infrastructure facilities and across EU Member States. Based on a review of economic literature and on a series of in-depth case studies, this study explains these differences in choices of regulation from differences in policy objectives, differences in local circumstances and differences in the intrinsic characteristics of the infrastructure projects. An important conclusion is that there is potential for a larger role for competition in gas infrastructure expansion.

RTEL1 inhibits trinucleotide repeat expansions and fragility.

Science.gov (United States)

Frizzell, Aisling; Nguyen, Jennifer H G; Petalcorin, Mark I R; Turner, Katherine D; Boulton, Simon J; Freudenreich, Catherine H; Lahue, Robert S

2014-03-13

Human RTEL1 is an essential, multifunctional helicase that maintains telomeres, regulates homologous recombination, and helps prevent bone marrow failure. Here, we show that RTEL1 also blocks trinucleotide repeat expansions, the causal mutation for 17 neurological diseases. Increased expansion frequencies of (CTG⋅CAG) repeats occurred in human cells following knockdown of RTEL1, but not the alternative helicase Fbh1, and purified RTEL1 efficiently unwound triplet repeat hairpins in vitro. The expansion-blocking activity of RTEL1 also required Rad18 and HLTF, homologs of yeast Rad18 and Rad5. These findings are reminiscent of budding yeast Srs2, which inhibits expansions, unwinds hairpins, and prevents triplet-repeat-induced chromosome fragility. Accordingly, we found expansions and fragility were suppressed in yeast srs2 mutants expressing RTEL1, but not Fbh1. We propose that RTEL1 serves as a human analog of Srs2 to inhibit (CTG⋅CAG) repeat expansions and fragility, likely by unwinding problematic hairpins. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Phylogenetic relationships, diversification and expansion of chili peppers (Capsicum, Solanaceae).

Science.gov (United States)

Carrizo García, Carolina; Barfuss, Michael H J; Sehr, Eva M; Barboza, Gloria E; Samuel, Rosabelle; Moscone, Eduardo A; Ehrendorfer, Friedrich

2016-07-01

Capsicum (Solanaceae), native to the tropical and temperate Americas, comprises the well-known sweet and hot chili peppers and several wild species. So far, only partial taxonomic and phylogenetic analyses have been done for the genus. Here, the phylogenetic relationships between nearly all taxa of Capsicum were explored to test the monophyly of the genus and to obtain a better knowledge of species relationships, diversification and expansion. Thirty-four of approximately 35 Capsicum species were sampled. Maximum parsimony and Bayesian inference analyses were performed using two plastid markers (matK and psbA-trnH) and one single-copy nuclear gene (waxy). The evolutionary changes of nine key features were reconstructed following the parsimony ancestral states method. Ancestral areas were reconstructed through a Bayesian Markov chain Monte Carlo analysis. Capsicum forms a monophyletic clade, with Lycianthes as a sister group, following both phylogenetic approaches. Eleven well-supported clades (four of them monotypic) can be recognized within Capsicum, although some interspecific relationships need further analysis. A few features are useful to characterize different clades (e.g. fruit anatomy, chromosome base number), whereas some others are highly homoplastic (e.g. seed colour). The origin of Capsicum is postulated in an area along the Andes of western to north-western South America. The expansion of the genus has followed a clockwise direction around the Amazon basin, towards central and south-eastern Brazil, then back to western South America, and finally northwards to Central America. New insights are provided regarding interspecific relationships, character evolution, and geographical origin and expansion of Capsicum A clearly distinct early-diverging clade can be distinguished, centred in western-north-western South America. Subsequent rapid speciation has led to the origin of the remaining clades. The diversification of Capsicum has culminated in the origin

Phylogenetic relationships, diversification and expansion of chili peppers (Capsicum, Solanaceae)

Science.gov (United States)

Carrizo García, Carolina; Barfuss, Michael H. J.; Sehr, Eva M.; Barboza, Gloria E.; Samuel, Rosabelle; Moscone, Eduardo A.; Ehrendorfer, Friedrich

2016-01-01

Background and Aims Capsicum (Solanaceae), native to the tropical and temperate Americas, comprises the well-known sweet and hot chili peppers and several wild species. So far, only partial taxonomic and phylogenetic analyses have been done for the genus. Here, the phylogenetic relationships between nearly all taxa of Capsicum were explored to test the monophyly of the genus and to obtain a better knowledge of species relationships, diversification and expansion. Methods Thirty-four of approximately 35 Capsicum species were sampled. Maximum parsimony and Bayesian inference analyses were performed using two plastid markers (matK and psbA-trnH) and one single-copy nuclear gene (waxy). The evolutionary changes of nine key features were reconstructed following the parsimony ancestral states method. Ancestral areas were reconstructed through a Bayesian Markov chain Monte Carlo analysis. Key Results Capsicum forms a monophyletic clade, with Lycianthes as a sister group, following both phylogenetic approaches. Eleven well-supported clades (four of them monotypic) can be recognized within Capsicum, although some interspecific relationships need further analysis. A few features are useful to characterize different clades (e.g. fruit anatomy, chromosome base number), whereas some others are highly homoplastic (e.g. seed colour). The origin of Capsicum is postulated in an area along the Andes of western to north-western South America. The expansion of the genus has followed a clockwise direction around the Amazon basin, towards central and south-eastern Brazil, then back to western South America, and finally northwards to Central America. Conclusions New insights are provided regarding interspecific relationships, character evolution, and geographical origin and expansion of Capsicum. A clearly distinct early-diverging clade can be distinguished, centred in western–north-western South America. Subsequent rapid speciation has led to the origin of the remaining clades. The

Longitudinal expansion of field line dipolarization

Science.gov (United States)

Saka, O.; Hayashi, K.

2017-11-01

We examine the substorm expansions that started at 1155 UT 10 August 1994 in the midnight sector focusing on the longitudinal (eastward) expansion of field line dipolarization in the auroral zone. Eastward expansion of the dipolarization region was observed in all of the H, D, and Z components. The dipolarization that started at 1155 UT (0027 MLT) from 260° of geomagnetic longitude (CMO) expanded to 351°(PBQ) in about 48 min. The expansion velocity was 0.03-0.04°/s, or 1.9 km/s at 62°N of geomagnetic latitude. The dipolarization region expanding to the east was accompanied by a bipolar event at the leading edge of the expansion in latitudes equatorward of the westward electrojet (WEJ). In the midnight sector at the onset meridian, the Magnetospheric Plasma Analyzer (MAP) on board geosynchronous satellite L9 measured electrons and ions between 10 eV and 40 keV. We conclude from the satellite observations that this dipolarization was characterized by the evolution of temperature anisotropies, an increase of the electron and ion temperatures, and a rapid change in the symmetry axis of the temperature tensor. The field line dipolarization and its longitudinal expansion were interpreted in terms of the slow MHD mode triggered by the current disruption. We propose a new magnetosphere-ionosphere coupling (MI-coupling) mechanism based on the scenario that transmitted westward electric fields from the magnetosphere in association with expanding dipolarization produced electrostatic potential (negative) in the ionosphere through differences in the mobility of collisional ions and collisionless electrons. The field-aligned currents that emerged from the negative potential region are arranged in a concentric pattern around the negative potential region, upward toward the center and downward on the peripheral.

Wilson expansion in the minimal subtraction scheme

International Nuclear Information System (INIS)

Smirnov, V.A.

1989-01-01

The small distance expansion of the product of composite fields is constructed for an arbitrary renormalization procedure of the type of minimal subtraction scheme. Coefficient functions of the expansion are expressed explicitly through the Green functions of composite fields. The expansion has the explicity finite form: the ultraviolet (UV) divergences of the coefficient functions and composite fields are removed by the initial renormalization procedure while the infrared (IR) divergences in massless diagrams with nonvanishing contribution into the coefficient functions are removed by the R-operation which is the IR part of the R-operation. The latter is the generalization of the dimensional renormalization in the case when both UV and IR divergences are present. To derive the expansion, a ''pre-subtracting operator'' is introduced and formulas of the counter-term technique are exploited

77 FR 65815 - Expansion of Fagatele Bay National Marine Sanctuary, Regulatory Changes, and Sanctuary Name...

Science.gov (United States)

2012-10-31

.... 070726412-1300-02] RIN 0648-BA24 Expansion of Fagatele Bay National Marine Sanctuary, Regulatory Changes, and Sanctuary Name Change; Notice of Effective Date AGENCY: Office of National Marine Sanctuaries... geographical areas to the sanctuary and change the name of the Fagatele Bay National Marine Sanctuary (FBNMS or...

Thermal Expansion Anomaly Regulated by Entropy

Science.gov (United States)

Liu, Zi-Kui; Wang, Yi; Shang, Shunli

2014-11-01

Thermal expansion, defined as the temperature dependence of volume under constant pressure, is a common phenomenon in nature and originates from anharmonic lattice dynamics. However, it has been poorly understood how thermal expansion can show anomalies such as colossal positive, zero, or negative thermal expansion (CPTE, ZTE, or NTE), especially in quantitative terms. Here we show that changes in configurational entropy due to metastable micro(scopic)states can lead to quantitative prediction of these anomalies. We integrate the Maxwell relation, statistic mechanics, and first-principles calculations to demonstrate that when the entropy is increased by pressure, NTE occurs such as in Invar alloy (Fe3Pt, for example), silicon, ice, and water, and when the entropy is decreased dramatically by pressure, CPTE is expected such as in anti-Invar cerium, ice and water. Our findings provide a theoretic framework to understand and predict a broad range of anomalies in nature in addition to thermal expansion, which may include gigantic electrocaloric and electromechanical responses, anomalously reduced thermal conductivity, and spin distributions.

Natural range expansion and local extirpation of an exotic psittacine--an unsuccessful colonization attempt

Science.gov (United States)

Wiley, J.W.

1993-01-01

The Brown-throated Parakeet Aratinga pertinax is native to Panama, northern South America, and the islands off the northern coast of Venezuela. It is widely believed that the parakeet was introduced to St. Thomas, Virgin Islands, from Curacao before the mid-19th century, although no records exist as to when and how this may have occurred. The parakeet was not recorded from Vieques or Culebra islands or mainland Puerto Rico before 1975. However, in that year A. pertinax underwent an apparent natural range expansion from St. Thomas into each of these sites. The 5 birds in the eastern Puerto Rico population made 5 breeding attempts and fledged 11 young since their discovery in April1975. That population grew to a maximum size of 10 birds in June 1979. However there was only 1 bird left by July 1980, and the population no longer existed at the beginning of what would have been the 1982 breeding season. The populations on Culebra and Vieques islands were apparently extirpated by 1976. Losses in the eastern Puerto Rico population were low during the first four years of colonization, when reproduction was adequate and the mortality was low. However, between 1978 and the time of population disappearance in 1982, the expected extirpation was 0.999. Habitat use, general behavior, breeding biology, competitors and predators of the colonizing population in eastern Puerto Rico are described. Biogeographic, evolutionary, and conservation implications of these observations are discussed.

Thermal expansion of quaternary nitride coatings

Science.gov (United States)

Tasnádi, Ferenc; Wang, Fei; Odén, Magnus; Abrikosov, Igor A.

2018-04-01

The thermal expansion coefficient of technologically relevant multicomponent cubic nitride alloys are predicted using the Debye model with ab initio elastic constants calculated at 0 K and an isotropic approximation for the Grüneisen parameter. Our method is benchmarked against measured thermal expansion of TiN and Ti(1-x)Al x N as well as against results of molecular dynamics simulations. We show that the thermal expansion coefficients of Ti(1-x-y)X y Al x N (X  =  Zr, Hf, Nb, V, Ta) solid solutions monotonously increase with the amount of alloying element X at all temperatures except for Zr and Hf, for which they instead decrease for y≳ 0.5 .

Thermal and Hygric Expansion of High Performance Concrete

Directory of Open Access Journals (Sweden)

J. Toman

2001-01-01

Full Text Available The linear thermal expansion coefficient of two types of high performance concrete was measured in the temperature range from 20 °C to 1000 °C, and the linear hygric expansion coefficient was determined in the moisture range from dry material to saturation water content. Comparative methods were applied for measurements of both coefficients. The experimental results show that both the effect of temperature on the values of linear thermal expansion coefficients and the effect of moisture on the values of linear hygric expansion coefficients are very significant and cannot be neglected in practical applications.

Parametric analysis of diffuser requirements for high expansion ratio space engine

Science.gov (United States)

Wojciechowski, C. J.; Anderson, P. G.

1981-01-01

A supersonic diffuser ejector design computer program was developed. Using empirically modified one dimensional flow methods the diffuser ejector geometry is specified by the code. The design code results for calculations up to the end of the diffuser second throat were verified. Diffuser requirements for sea level testing of high expansion ratio space engines were defined. The feasibility of an ejector system using two commonly available turbojet engines feeding two variable area ratio ejectors was demonstrated.

The effect of particle structure on apparent density of electrolytic copper powder

Directory of Open Access Journals (Sweden)

K. I. POPOV

2001-12-01

Full Text Available The quantitative microstructural analysis and the sieve analysis of copper powder as well as the scanning electron microscopy analysis of the copper powders particles were performed. It was found that the structure of the copper powder particles determines the apparent density of copper powder. The powder particles from the same fractions of different powders occupy approximately the same volume, but the structure of metallic copper is very different. This causes the difference in apparent densities of copper powder obtained under different conditions. The more dendritic is the structure of powder particles the smaller is the apparent density of copper powder.

Parabolic cyclinder functions : examples of error bounds for asymptotic expansions

NARCIS (Netherlands)

R. Vidunas; N.M. Temme (Nico)

2002-01-01

textabstractSeveral asymptotic expansions of parabolic cylinder functions are discussedand error bounds for remainders in the expansions are presented. Inparticular Poincaré-type expansions for large values of the argument$z$ and uniform expansions for large values of the parameter areconsidered.

13 CFR 120.835 - Application to expand an Area of Operations.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Application to expand an Area of Operations. 120.835 Section 120.835 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS... program responsibilities in the proposed area. (b) Local Economic Area Expansion. A CDC seeking to expand...

A unification of boson expansion theories. (III) Applications

International Nuclear Information System (INIS)

Dobaczewski, J.

1981-10-01

A general scheme of constructing boson expansions that was proposed in earlier work is applied to a number or examples. The Fukutome expansion is obtained by considering the spinor representation of the SO(2N+1) group. Its hermitian, Holstein-Primakofr-type version is also derived. The generalized Dyson expansions for even and odd fermion systems are given in terms of two spinor representations of the SO(2N) group. For fixed fermion number systems the relevant boson expansions are obtained by considering the fundamental representations of SU(N) while for fixed seniority those of Sp(N) are concerned. The collective boson expansions corresponding to the Ginocchio model, the interacting boson model of Arima and Iachello and the Elliot model are given for the symmetric representations of SO(8) and SU(1+1) and any representation of SU(3)

Discrete expansions of continuum functions. General concepts

International Nuclear Information System (INIS)

Bang, J.; Ershov, S.N.; Gareev, F.A.; Kazacha, G.S.

1979-01-01

Different discrete expansions of the continuum wave functions are considered: pole expansion (according to the Mittag-Lefler theorem), Weinberg states. The general property of these groups of states is their completeness in the finite region of space. They satisfy the Schroedinger type equations and are matched with free solutions of the Schroedinger equation at the boundary. Convergence of expansions for the S matrix, the Green functions and the continuous-spectrum wave functions is studied. A new group of states possessing the best convergence is introduced

Edgeworth expansion for the pre-averaging estimator

DEFF Research Database (Denmark)

Podolskij, Mark; Veliyev, Bezirgen; Yoshida, Nakahiro

In this paper, we study the Edgeworth expansion for a pre-averaging estimator of quadratic variation in the framework of continuous diffusion models observed with noise. More specifically, we obtain a second order expansion for the joint density of the estimators of quadratic variation and its...... asymptotic variance. Our approach is based on martingale embedding, Malliavin calculus and stable central limit theorems for continuous diffusions. Moreover, we derive the density expansion for the studentized statistic, which might be applied to construct asymptotic confidence regions....

Oblique photon expansion of QED structure functions

International Nuclear Information System (INIS)

Chahine, C.

1986-01-01

In the oblique photon expansion, the collinear part of photon emission is summed up to all orders in perturbation theory. The number of oblique or non-collinear photons is the expansion order. Unlike in perturbation theory, every term of the expansion is both infrared finite and gauge invariant. The zero oblique photon contribution to the electromagnetic structure tensor in QED is computed in detail. The behaviors of the structure functions F1 and F2 are discussed in the soft and ultra-soft limits

Multiscale analysis of deforestation risk due to commodity crop expansion in sub-Saharan Africa and the role of non-industrial producers

Science.gov (United States)

Ordway, E.; Asner, G. P.; Naylor, R. L.; Nkongho, R.; Lambin, E.

2017-12-01

Rapid integration of global agricultural markets and subsequent cropland displacement in recent decades increased large-scale tropical deforestation in South America and Southeast Asia. Growing land scarcity and more stringent land use regulations in these regions could incentivize the offshoring of export-oriented commodity crop production to sub-Saharan Africa (SSA). We assess the effects of domestic- and export-oriented agricultural expansion on deforestation in SSA in recent decades at the global, regional and local scales. Using Cameroon as a case-study, we explore the influence of emerging oil palm expansion on deforestation in greater depth. We found that commodity crops are expanding in SSA, increasing pressure on tropical forests. Four Congo Basin countries, Sierra Leone, Liberia, and Cote d'Ivoire were most at risk in terms of exposure, vulnerability and pressures from agricultural expansion. These countries averaged the highest percent forest cover (58% ±17.9) and lowest proportions of potentially available cropland outside forest areas (1% ±0.9). Foreign investment in these countries was concentrated in oil palm production (81%), with a median investment area of 41,582 thousand ha. Based on remote sensing and field survey results, however, medium- and large-scale non-industrial producers are driving a substantial fraction of the oil palm expansion leading to deforestation in Cameroon. Additionally, unlike Southeast Asia, oil palm expansion in sub-Saharan Africa is associated primarily with domestic market demands. In contrast, cocoa, the fastest expanding export-oriented crop across SSA, accounted for 57% of global expansion in 2000-2013 at a rate of 132 thousand ha yr-1, yet only amounted to 0.9% of foreign land investment. Commodity crop expansion in SSA appears largely driven by small- and medium-scale farmers rather than industrial plantations. Findings highlight that, although most agricultural expansion was associated with domestic demand, there

Prediction of vertical expansion pressure stresses in coke oven heating walls

Energy Technology Data Exchange (ETDEWEB)

Duerselen, H; Janicka, J

1987-08-01

The paper describes an accurate method developed by Krupp Koppers for calculating stresses in the central areas of coke oven heating walls. The results of this calculation model have provided the following conclusions for the design of coke ovens: 1) a rising pre-stressing of the heating walls caused by the weight of the top deck of the coke oven leads - compared with the stress limits of W. Ahlers - to lower permissible expansion pressures. 2) A given heating wall width has its corresponding maximum feasible oven height. Heating wall width and top deck weight are not interchangeable parameters. 3) The dependence of the permissible expansion pressure on the stretcher brick thickness should not be overlooked. Stretcher brick thicknesses of under 90 mm are not recomended for tall ovens and heavily swelling coal. 4) The capacity of mortar to absorb tensile stresses is ultimately an undesirable property, because the stresses at the points where the mortar is not holding are higher than in a straightforward stretch of brickwork.

Tertiary work-up of apparent treatment-resistant hypertension.

Science.gov (United States)

Heimark, Sondre; Eskås, Per Anders; Mariampillai, Julian Eek; Larstorp, Anne Cecilie K; Høieggen, Aud; Fadl Elmula, Fadl Elmula M

2016-10-01

Treatment-resistant hypertension (TRH) has regained attention with development of new methods for treatment. However, the prevalence of TRH varies considerably from primary to secondary and tertiary care. We aimed to assess the prevalence of true TRH in a population of patients with apparent TRH in a university hospital setting of tertiary work-up and also investigate reasons for poor BP control and evaluate how work-up can be performed in general practice and secondary care. In this cohort study, we characterize a study population from Oslo Renal Denervation (RDN) Study. Patients (n = 83) were referred for RDN from secondary care. All patients underwent thorough medical investigation and 24-h ambulatory blood pressure measurements (24ABPM) after directly observed therapy (DOT). We then assessed reasons for lack of BP control. Fifty-three of 83 patients did not have true TRH. Main reasons for non-TRH were poor drug adherence (32%), secondary hypertension (30%) and white coat hypertension (15%). Forty-seven percent achieved blood pressure control after DOT with subsequent 24ABPM. There were otherwise no statistically significant differences in patient characteristics between the true TRH and the non-TRH group. Despite being a highly selected cohort referred for tertiary work-up of apparent TRH, BP control was achieved or secondary causes were identified in almost two thirds of the patients. Thorough investigation according to guidelines and DOT with subsequent 24ABPM is needed in work-up of apparent TRH.

AUTO-EXPANSIVE FLOW

Science.gov (United States)

Physics suggests that the interplay of momentum, continuity, and geometry in outward radial flow must produce density and concomitant pressure reductions. In other words, this flow is intrinsically auto-expansive. It has been proposed that this process is the key to understanding...

Thermal expansion behaviour of high performance PEEK matrix composites

International Nuclear Information System (INIS)

Goyal, R K; Mulik, U P; Tiwari, A N; Negi, Y S

2008-01-01

The thermal expansion behaviour of high performance poly(ether-ether-ketone) (PEEK) composites reinforced with micro- (8 μm) and nano- (39 nm) sized Al 2 O 3 particles was studied. The distribution of Al 2 O 3 in the PEEK matrix was studied by scanning electron microscopy and transmission electron microscopy. The coefficient of thermal expansion (CTE) was reduced from 58 x 10 -6 deg. C -1 for pure PEEK to 22 x 10 -6 deg. C -1 at 43 vol% micro-Al 2 O 3 and to 23 x 10 -6 deg. C -1 at 12 vol% nano-Al 2 O 3 composites. For a given volume fraction, nano-Al 2 O 3 particles are more effective in reducing the CTE of composites than that of micro-Al 2 O 3 particles. This may be attributed to the much higher interfacial area or volume of nanocomposites than that of microcomposites. The upper limit and lower limit of the Schapery model separately fit closely the CTE of the micro- and nano-composites, respectively. Other models such as the rule of mixture and Kerner and Turner models were also correlated with the data

Studies of Expansive Learning: Foundations, Findings and Future Challenges

Directory of Open Access Journals (Sweden)

Yrjö Engeström

2013-07-01

Full Text Available The paper examines studies based on the theory of expansive learning, formulated in 1987. In recent years the theory has been used in a wide variety of studies and interventions. The theory builds on foundational ideas put forward by Vygotsky, Leont’ev, Il’enkov, and Davydov, key figures in the Russian school of cultural-historical activity theory. Studies based on the theory are reviewed in six sections: expansive learning as transformation of the object, expansive learning as movement in the zone of proximal development, expansive learning as cycles of learning actions, expansive learning as boundary crossing and network building, expansive learning as distributed and discontinuous movement, and formative interventions.A separate section is devoted to critiques of expansive learning. It is concluded that the ultimate test of learning theories is how they help practitioners to generate learning that grasps pressing issues the humankind is facing. The theory of expansive learning currently expands its analyses both up and down, outward and inward. Moving up and outward, it tackles learning in fields or networks of interconnected activity systems with their partially shared and often contested objects. Moving down and inward, it tackles issues of subjectivity, experiencing, personal sense, emotion, embodiment, identity, and moral commitment.

A Power Series Expansion and Its Applications

Science.gov (United States)

Chen, Hongwei

2006-01-01

Using the power series solution of a differential equation and the computation of a parametric integral, two elementary proofs are given for the power series expansion of (arcsin x)[squared], as well as some applications of this expansion.

Expansion Under Climate Change: The Genetic Consequences.

Science.gov (United States)

Garnier, Jimmy; Lewis, Mark A

2016-11-01

Range expansion and range shifts are crucial population responses to climate change. Genetic consequences are not well understood but are clearly coupled to ecological dynamics that, in turn, are driven by shifting climate conditions. We model a population with a deterministic reaction-diffusion model coupled to a heterogeneous environment that develops in time due to climate change. We decompose the resulting travelling wave solution into neutral genetic components to analyse the spatio-temporal dynamics of its genetic structure. Our analysis shows that range expansions and range shifts under slow climate change preserve genetic diversity. This is because slow climate change creates range boundaries that promote spatial mixing of genetic components. Mathematically, the mixing leads to so-called pushed travelling wave solutions. This mixing phenomenon is not seen in spatially homogeneous environments, where range expansion reduces genetic diversity through gene surfing arising from pulled travelling wave solutions. However, the preservation of diversity is diminished when climate change occurs too quickly. Using diversity indices, we show that fast expansions and range shifts erode genetic diversity more than slow range expansions and range shifts. Our study provides analytical insight into the dynamics of travelling wave solutions in heterogeneous environments.

Improvement of Expansive Soils Using Chemical Stabilizers

Science.gov (United States)

Ikizler, S. B.; Senol, A.; Khosrowshahi, S. K.; Hatipoğlu, M.

2014-12-01

The aim of this study is to investigate the effect of two chemical stabilizers on the swelling potential of expansive soil. A high plasticity sodium bentonite was used as the expansive soil. The additive materials including fly ash (FA) and lime (L) were evaluated as potential stabilizers to decrease the swelling pressure of bentonite. Depending on the type of additive materials, they were blended with bentonite in different percentages to assess the optimum state and approch the maximum swell pressure reduction. According to the results of swell pressure test, both fly ash and lime reduce the swelling potential of bentonite but the maximum improvement occurs using bentonite-lime mixture while the swelling pressure reduction approaches to 49%. The results reveal a significant reduction of swelling potential of expansive soil using chemical stabilizers. Keywords: Expansive soil; swell pressure; chemical stabilization; fly ash; lime

Strong-coupling expansion for the ground-state energy in the Vertical BarxVertical Bar/sup α/ potential

International Nuclear Information System (INIS)

Bender, C.M.; Mead, L.R.; Simmons, L.M. Jr.

1981-01-01

Using lattice techniques we examine the strong-coupling expansion for the ground-state energy of a gVertical BarxVertical Bar/sup α/ (α>0) potential in quantum mechanics. We are particularly interested in studying the effectiveness of various Pade-type methods for extrapolating the lattice series back to the continuum. We have computed the lattice series out to 12th order for all α and we identify three regions. When α or =2 the lattice series has a finite radius of convergence; here, completely-off-diagonal Pade extrapolants work best. As α increases beyond 2 it becomes more difficult to obtain good continuum results, apparently because the sign pattern of the lattice series seems to fluctuate randomly. The onset of randomness occurs earlier in the lattice series as α→infinity

A Non-Mainstream Viewpoint on Apparent Superluminal ...

Indian Academy of Sciences (India)

Abstract. The group velocity of light in material around the AGN jet is acquiescently one (c as a unit), but this is only a hypothesis. Here, we re-derive apparent superluminal and Doppler formulas for the general case (it is assumed that the group velocity of light in the uniform and isotropic medium around a jet (a beaming ...

Thermal expansion: Metallic elements and alloys. [Handbook

Science.gov (United States)

Touloukian, Y. S.; Kirby, R. K.; Taylor, R. E.; Desai, P. D.

1975-01-01

The introductory sections of the work are devoted to the theory of thermal expansion of solids and to methods for the measurement of the linear thermal expansion of solids (X-ray methods, high speed methods, interferometry, push-rod dilatometry, etc.). The bulk of the work is devoted to numerical data on the thermal linear expansion of all the metallic elements, a large number of intermetallics, and a large number of binary alloy systems and multiple alloy systems. A comprehensive bibliography is provided along with an index to the materials examined.

Some Improved Nonperturbative Bounds for Fermionic Expansions

Energy Technology Data Exchange (ETDEWEB)

Lohmann, Martin, E-mail: marlohmann@gmail.com [Universita di Roma Tre, Dipartimento di Matematica (Italy)

2016-06-15

We reconsider the Gram-Hadamard bound as it is used in constructive quantum field theory and many body physics to prove convergence of Fermionic perturbative expansions. Our approach uses a recursion for the amplitudes of the expansion, discovered in a model problem by Djokic (2013). It explains the standard way to bound the expansion from a new point of view, and for some of the amplitudes provides new bounds, which avoid the use of Fourier transform, and are therefore superior to the standard bounds for models like the cold interacting Fermi gas.

Expansive focal cemento-osseous dysplasia.

Science.gov (United States)

Bulut, Emel Uzun; Acikgoz, Aydan; Ozan, Bora; Zengin, Ayse Zeynep; Gunhan, Omer

2012-01-01

To present a case of expansive focal cemento-osseous dysplasia and emphasize the importance of differential diagnosis. Cemento-osseous dysplasia is categorized into three subtypes on the basis of the clinical and radiographic features: Periapical, focal and florid. The focal type exhibits a single site of involvement in any tooth-bearing or edentulous area of the jaws. These lesions are usually asymptomatic; therefore, they are frequently diagnosed incidentally during routine radiographic examinations. Lesions are usually benign, show limited growth, and do not require further surgical intervention, but periodic follow-up is recommended because occasionally, this type of dysplasia progresses into florid osseous dysplasia and simple bone cysts are formed. A 24-year-old female patient was referred to our clinic for swelling in the left edentulous mandibular premolarmolar region and felt discomfort when she wore her prosthetics. She had no pain, tenderness or paresthesia. Clinical examination showed that the swelling in the posterior mandible that was firm, nonfluctuant and covered by normal mucosa. On panoramic radiography and computed tomography, a well defined lesion of approximately 1.5 cm in diameter of mixed density was observed. The swelling increased slightly in size over 2 years making it difficult to use prosthetics and, therefore, the lesion was totally excised under local anesthesia, and surgical specimens were submitted for histopathological examination. The histopathological diagnosis was focal cemento-osseous dysplasia. In the present case, because of the increasing size of the swelling making it difficult to use prosthetics, young age of the patient and localization of the lesion, in the initial examination, cemento-ossifying fibroma was suspected, and the lesion was excised surgically; the histopathological diagnosis confirmed it as focal cemento-osseous dysplasia. We present a case of expansive focal cemento-osseous dysplasia. Differential diagnosis

On the Fer expansion: Applications in solid-state nuclear magnetic resonance and physics

Energy Technology Data Exchange (ETDEWEB)

Mananga, Eugene Stephane, E-mail: esm041@mail.harvard.edu

2016-01-18

Theoretical approaches are useful and powerful tools for more accurate and efficient spin dynamics simulation to understand experiments and devising new RF pulse sequence in nuclear magnetic resonance. Solid-state NMR is definitely a timely topic or area of research, and not many papers on the respective theories are available in the literature of nuclear magnetic resonance or physics reports. This report presents the power and the salient features of the promising theoretical approach called Fer expansion that is helpful to describe the evolution of the spin system in nuclear magnetic resonance. The report presents a broad view of algorithms of spin dynamics based on the Fer expansion which provides procedures to control and describe the spin dynamics in solid-state NMR. Significant applications of the Fer expansion are illustrated in NMR and in physics such as classical physics, nonlinear dynamics systems, celestial mechanics and dynamical astronomy, hydrodynamics, nuclear, atomic, molecular physics, and quantum mechanics, quantum field theory, high energy physics, electromagnetism. The aim of this report is to bring to the attention of the spin dynamics community, the bridge that exists between solid-state NMR and other related fields of physics and applied mathematics.

On the Fer expansion: Applications in solid-state nuclear magnetic resonance and physics

International Nuclear Information System (INIS)

Mananga, Eugene Stephane

2016-01-01

Theoretical approaches are useful and powerful tools for more accurate and efficient spin dynamics simulation to understand experiments and devising new RF pulse sequence in nuclear magnetic resonance. Solid-state NMR is definitely a timely topic or area of research, and not many papers on the respective theories are available in the literature of nuclear magnetic resonance or physics reports. This report presents the power and the salient features of the promising theoretical approach called Fer expansion that is helpful to describe the evolution of the spin system in nuclear magnetic resonance. The report presents a broad view of algorithms of spin dynamics based on the Fer expansion which provides procedures to control and describe the spin dynamics in solid-state NMR. Significant applications of the Fer expansion are illustrated in NMR and in physics such as classical physics, nonlinear dynamics systems, celestial mechanics and dynamical astronomy, hydrodynamics, nuclear, atomic, molecular physics, and quantum mechanics, quantum field theory, high energy physics, electromagnetism. The aim of this report is to bring to the attention of the spin dynamics community, the bridge that exists between solid-state NMR and other related fields of physics and applied mathematics.

A non-uniform expansion mechanical safety model of the stent.

Science.gov (United States)

Yang, J; Huang, N; Du, Q

2009-01-01

Stents have a serial unstable structure that readily leads to non-uniform expansion. Non-uniform expansion in turn creates a stent safety problem. We explain how a stent may be simplified to a serial unstable structure, and present a method to calculate the non-uniform expansion of the stent on the basis of the serial unstable structure. We propose a safety criterion based on the expansion displacement instead of the strain, and explain that the parameter Rd, the ratio of the maximum displacement of the elements to normal displacement, is meaningful to assess the safety level of the stent. We also examine how laser cutting influences non-uniform expansion. The examples illustrate how to calculate the parameter Rd to assess non-uniform expansion of the stent, and demonstrate how the laser cutting offset and strengthening coefficient of the material influence the stent expansion behaviour. The methods are valuable for assessing stent safety due to non-uniform expansion.

The economics of renewable energy expansion in rural Sub-Saharan Africa

International Nuclear Information System (INIS)

Deichmann, Uwe; Meisner, Craig; Murray, Siobhan; Wheeler, David

2011-01-01

Accelerating development in Sub-Saharan Africa will require massive expansion of access to electricity-currently reaching only about one third of households. This paper explores how essential economic development might be reconciled with the need to keep carbon emissions in check. We develop a geographically explicit framework and use spatial modeling and cost estimates from recent engineering studies to determine where stand-alone renewable energy generation is a cost effective alternative to centralized grid supply. Our results suggest that decentralized renewable energy will likely play an important role in expanding rural energy access. However, it will be the lowest cost option for a minority of households in Africa, even when likely cost reductions over the next 20 years are considered. Decentralized renewables are competitive mostly in remote and rural areas, while grid connected supply dominates denser areas where the majority of households reside. These findings underscore the need to decarbonize the fuel mix for centralized power generation as it expands in Africa. - Research highlights: → Expansion of electricity access in Sub-Saharan Africa remains a development priority. → Low carbon options are important to reduce GHG emissions growth and avoid lock-ins. → Spatially explicit cost modeling guides choice of supply options. → Decentralized renewables are lowest cost for a significant minority of households. → Grid supply remains attractive, suggesting focus on decarbonizing centralized supply.

Synthesis, microstructure and thermal expansion studies

Indian Academy of Sciences (India)

Abstract. We report on the synthesis, microstructure and thermal expansion studies on Ca0.5+/2Sr0.5+/2Zr4P6−2Si2O24 ( = 0.00 to 1.00) system which belongs to NZP family of low thermal expansion ceramics. The ceramics synthesized by co-precipitation method at lower calcination and the sintering temperatures ...

Operator expansion in quantum chromodynamics beyond perturbation theory

International Nuclear Information System (INIS)

Novikov, V.A.; Shifman, M.A.; Vainshtejn, A.I.; Zakharov, V.I.

1980-01-01

The status of operator expansion at short distances is descussed within the frameworks of nonperturbatue QCD. The question of instanton effects is investigated in various aspects. Two-point functions induced by the gluonic currents are considered. It is shown that certain gluonic correlations vanish in the field of definite duality. It is proved that there does exist a very special relation between the expansion coefficients required by consistancy between instanton calculations and the general operator expansion. At last a certain modification of the naive version of operator expansion is proposed, which allows one to go beyond the critical power and construct, if necessary, an infinite series

Studying medium effects with the optimized δ expansion

International Nuclear Information System (INIS)

Krein, G.; Menezes, D.P.; Nielsen, M.; Pinto, M.B.

1995-04-01

The possibility of using the optimized δ expansion for studying medium effects on hadronic properties in quark or nuclear matter is investigated. The δ expansion is employed to study density effects with two commonly used models in hadron and nuclear physics, the Nambu-Jona-Lasinio model for the dynamical chiral symmetry breaking and the Walecka model for the equation of state of nuclear matter. The results obtained with the δ expansion are compared to those obtained with the traditional Hartree-Fock approximation. Perspectives for using the δ expansion in other field theoretic models in hadron and nuclear physics are discussed. (author). 17 refs, 9 figs

Studying medium effects with the optimized {delta} expansion

Energy Technology Data Exchange (ETDEWEB)

Krein, G [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Menezes, D P [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Fisica; Nielsen, M [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Pinto, M B [Montpellier-2 Univ., 34 (France). Lab. de Physique Mathematique

1995-04-01

The possibility of using the optimized {delta} expansion for studying medium effects on hadronic properties in quark or nuclear matter is investigated. The {delta} expansion is employed to study density effects with two commonly used models in hadron and nuclear physics, the Nambu-Jona-Lasinio model for the dynamical chiral symmetry breaking and the Walecka model for the equation of state of nuclear matter. The results obtained with the {delta} expansion are compared to those obtained with the traditional Hartree-Fock approximation. Perspectives for using the {delta} expansion in other field theoretic models in hadron and nuclear physics are discussed. (author). 17 refs, 9 figs.

Sprawl and mega-events: Economic growth and recent urban expansion in a city losing its competitive edge (Athens, Greece

Directory of Open Access Journals (Sweden)

Luca Salvati

2017-12-01

Full Text Available In the new context of contemporary cities, local competitiveness for financial resources has grown more than ever, resulting in cities characterised by important socioeconomic transformations. Earlier studies addressed the relation between urban expansion, socioeconomic development and mega-events only for specific areas and types of urban growth, often overlooking the role of mega-events in fuelling urban sprawl. As the host of the 2004 Olympic Games, Athens, Greece is a paradigmatic example for emerging cities hosting mega-events due to the close interconnection between the Olympics, infrastructure development and urban sprawl. This article connects the latent relationship between economic expansion driven by the Olympic Games and laissez-faire urbanism to the long-term unregulated urban expansion characterising Athens’s development. By providing room for the original wave of sprawl, the resulting socioeconomic context is interpreted as a signal of the weakness of the “competitive city” framework in poorly planned and long-deregulated urban contexts such as Athens. A comprehensive analysis of recent phases of economic growth and discontinuous urban expansion thus provides further insight into understanding sprawl processes in today’s cities, and helps distinguish the morphological patterns and socioeconomic dynamics that characterise urban expansion during sequential cycles of economic expansion and recession.

Anisotropic thermal expansion in flexible materials

Science.gov (United States)

Romao, Carl P.

2017-10-01

A definition of the Grüneisen parameters for anisotropic materials is derived based on the response of phonon frequencies to uniaxial stress perturbations. This Grüneisen model relates the thermal expansion in a given direction (αi i) to one element of the elastic compliance tensor, which corresponds to the Young's modulus in that direction (Yi i). The model is tested through ab initio prediction of thermal expansion in zinc, graphite, and calcite using density functional perturbation theory, indicating that it could lead to increased accuracy for structurally complex systems. The direct dependence of αi i on Yi i suggests that materials which are flexible along their principal axes but rigid in other directions will generally display both positive and negative thermal expansion.

Zebrafish usp39 mutation leads to rb1 mRNA splicing defect and pituitary lineage expansion.

Directory of Open Access Journals (Sweden)

Yesenia Ríos

2011-01-01

Full Text Available Loss of retinoblastoma (Rb tumor suppressor function is associated with human malignancies. Molecular and genetic mechanisms responsible for tumorigenic Rb downregulation are not fully defined. Through a forward genetic screen and positional cloning, we identified and characterized a zebrafish ubiquitin specific peptidase 39 (usp39 mutation, the yeast and human homolog of which encodes a component of RNA splicing machinery. Zebrafish usp39 mutants exhibit microcephaly and adenohypophyseal cell lineage expansion without apparent changes in major hypothalamic hormonal and regulatory signals. Gene expression profiling of usp39 mutants revealed decreased rb1 and increased e2f4, rbl2 (p130, and cdkn1a (p21 expression. Rb1 mRNA overexpression, or antisense morpholino knockdown of e2f4, partially reversed embryonic pituitary expansion in usp39 mutants. Analysis of pre-mRNA splicing status of critical cell cycle regulators showed misspliced Rb1 pre-mRNA resulting in a premature stop codon. These studies unravel a novel mechanism for rb1 regulation by a neuronal mRNA splicing factor, usp39. Zebrafish usp39 regulates embryonic pituitary homeostasis by targeting rb1 and e2f4 expression, respectively, contributing to increased adenohypophyseal sensitivity to these altered cell cycle regulators. These results provide a mechanism for dysregulated rb1 and e2f4 pathways that may result in pituitary tumorigenesis.

Accelerated Urban Expansion in Lhasa City and the Implications for Sustainable Development in a Plateau City

Directory of Open Access Journals (Sweden)

Wei Tang

2017-08-01

Full Text Available Urbanization challenges regional sustainable development, but a slight expansion mechanism was revealed in a plateau city. We have integrated the urban expansion process and analyzed its determinants in Lhasa (Tibet, and we provide insightful suggestions for urban management and planning for Lhasa. The full continuum of the urban expansion process has been captured using time-series of high-resolution remote sensing data (1990–2015. Four categories of potential determinants involved in economic, demographic, social, and government policy factors were selected, and redundancy analysis was employed to define the contribution rates of these determinants. The results illustrate that considerable urban expansion occurred from 1990 to 2015 in Lhasa, with the area of construction land and transportation land increasing at rates of 117.2% and 564.7%, respectively. The urban expansion in the center of Lhasa can be characterized as temperate sprawl from 1990 through 2008, primarily explained by governmental policies and investment, economic development, tourist growth, and increased governmental investment resulting in faster urban expansion from 2008 to 2015, mainly occurring in the east, south, and west of Lhasa. In contrast with other cities of China, central government investment and “pairing-up support” projects have played an important role in infrastructure construction in Lhasa. The miraculous development of the tourism industry had prominent effects on this economic development and urbanization after 2006, due to the running of the Tibetan Railway. An integrative and proactive policy framework, the “Lhasa development model”, having important theoretical, methodological, and management implications for urban planning and development, has been proposed.

Cluster expansion of the wavefunction. Symmetry-adapted-cluster expansion, its variational determination, and extension of open-shell orbital theory

International Nuclear Information System (INIS)

Nakatsuji, H.; Hirao, K.

1978-01-01

The symmetry-adapted-cluster (SAC) expansion of an exact wavefunction is given. It is constructed from the generators of the symmetry-adapted excited configurations having the symmetry under consideration, and includes their higher-order effect and self-consistency effect. It is different from the conventional cluster expansions in several important points, and is suitable for applications to open-shell systems as well as closed-shell systems. The variational equation for the SAC wavefunction has a form similar to the generalized Brillouin theorem in accordance with the inclusion of the higher-order effect and the self-consistency effect. We have expressed some existing open-shell orbital theories equivalently in the conventional cluster expansion formulas, and on this basis, we have given the pseudo-orbital theory which is an extension of open-shell orbital theory in the SAC expansion formula

Nurse prescribing as an aspect of future role expansion: the views of Irish clinical nurse specialists.

LENUS (Irish Health Repository)

Lockwood, Emily B

2008-10-01

AIM: Nurses and midwives are expanding the scope of their professional practice, assuming additional responsibilities including the management and prescribing of medications. The aim of the study was to discover the attitudes of clinical nurse specialists (CNSs) in Ireland to nurse prescribing and to examine perceived barriers to engaging in this aspect of future role expansion. BACKGROUND: The expansion of the nursing role in relation to nurse prescribing is an ongoing process and is subject to incremental iterations of legislation and professional policy. Nurse prescribing as an expanded role function has become a reality in many countries. Ireland has addressed the matter in a formal and systematic way through legislation. METHOD: A questionnaire was administered to a sample of 283 CNSs practising in a variety of care settings in Ireland. Attitudes were measured using Likert-type attitudinal scales, designed specifically for the study. RESULTS AND CONCLUSIONS: Findings indicate that the majority of clinical nurse specialists were positively disposed toward nurse prescribing as a future role expansion. The fear of litigation was identified as the most significant barrier to nurse prescribing. The majority of respondents equated nurse prescribing with increased autonomy and holistic care. The findings indicate that there is a need for further examination of the educational requirements of the CNS in relation to nurse prescribing. The legislative implications for nurse prescribing and fear of legal consequences need to be considered prior to any implementation of nurse prescribing. IMPLICATIONS FOR NURSING MANAGEMENT: While senior clinicians are willing to embrace future role expansion in the area of nurse prescribing, their Nurse Managers should recognize that facilitation of nurse prescribing needs to address the legal and educational requirements for such activity. Failure to address these requirements can represent a barrier to role expansion. This paper offers

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Directory of Open Access Journals (Sweden)

Mishra Shubham

2016-12-01

Full Text Available Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%, which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle. Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Science.gov (United States)

Mishra, Shubham; Sarkar, Jahar

2016-12-01

Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene) is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP) for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%), which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle). Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.